Dynamic demodulation signal resource allocation

Abstract

Systems, apparatus and methods for dynamic demodulation signal resource allocation are described. PDSCH / PUSCH DMRS enhancements are provided. Dynamic indication of reference signal functionality in slots for additional DM-RS can be provided. Configured CSI-RS / SRS can be dynamically indicated for use as additional DM-RS in a slot. Frequency shifting / frequency hopping of DM-RS as a function of order of OFDM symbols and / or OFDM symbols containing DM-RS can increase frequency density within a slot. DM-RS antenna port aggregation can increase DM-RS frequency density. One or more DM-RS antenna ports can be used for demodulation of the same layer. PDCCH DMRS enhancements are provided. Frequency shifting / frequency hopping of PDCCH DMRS can be provided as a function of REG index within a REG bundle, OFDM symbol index, etc. Usage of multiple types of REGs (e.g., low DM-RS and high DM-RS) and REG types can be determined based on subcarrier spacing, operating band, etc.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 985,994, filed March 6, 2020, and U.S. Provisional Patent Application Serial No. 63 / 134,859, filed January 7, 2021, the contents of which are incorporated herein by reference as if fully set forth herein. Technical Field

[0003] The embodiments disclosed herein relate to communications in general, and, for example, to methods, apparatus, and systems for dynamic demodulation reference signal (DM-RS) resource allocation and / or DM-RS enhancement. Background Technology

[0004] Mobile communication using wireless communication continues to evolve. The fifth generation can be called 5G, and the sixth generation can be called 6G. Previous generations (traditional) mobile communication can be, for example, fourth generation (4G) Long Term Evolution (LTE). Summary of the Invention

[0005] This document describes systems and methods for dynamic demodulation signal resource allocation. PDSCH / PUSCH DMRS enhancements are provided. Dynamic indication of reference signal functionality can be provided in time slots used for additional DM-RS. For example, configured CSI-RS / SRS can be dynamically indicated as additional DM-RS in a time slot. Frequency shifting / hopping of DM-RS as a function of the order of OFDM symbols and / or OFDM symbols containing DM-RS can increase the frequency density within a time slot or bundled time slot. DM-RS antenna port aggregation can increase DM-RS frequency density. One or more DM-RS antenna ports can be used to demodulate the same layer. DM-RS pattern determination can be performed for normal scheduling and / or time slot bundling. PDCCH DMRS enhancements are also provided. Frequency shifting / hopping of PDCCH DM-RS can be provided as a function of REG indexes, OFDM symbol indexes, etc., within a REG bundle. The use of various REG types (e.g., low DM-RS density and high DM-RS density) and REG types can be determined, for example, based on subcarrier spacing, operating frequency band, etc. Enhancements to PUCCH DM-RS are provided. Frequency shifting / hopping of PUCCH DM-RS can be provided based on any of the following: PUCCH format, symbol length, number of PRBs, etc. Multiple types of PUCCH DM-RS can be used (e.g., low DM-RS density and high DM-RS density), and multiple types of PUCCH DM-RS can be determined based on any of the following: subcarrier spacing, operating frequency band, etc.

[0006] In some representative implementations, a method may be implemented by a Wireless Transmit / Receive Unit (WTRU) to receive information indicating the configuration of a Control Resource Set (CORESET). The CORESET configuration includes indications of symbol duration and / or Physical Downlink Control Channel (PDCCH) demodulation reference signal (DM-RS) frequency hopping or density changes. The WTRU may receive information indicating the search space configuration of a search space associated with the CORESET. The search space configuration may include one or more Downlink Control Information (DCI) formats to be monitored and / or one or more aggregation levels associated with each of the one or more DCI formats. The WTRU may determine one or more DM-RS locations in one or more Resource Element Groups (REGs) of the CORESET and / or the search space associated with the CORESET. The WTRU may receive Physical Downlink Control Channel (PDCCH) transmissions in the search space associated with the CORESET. The WTRU may use one or more PDCCH DM-RS locations from the determined one or more DM-RS locations to decode the received PDCCH transmissions. The WTRU can receive Physical Downlink Shared Channel (PDSCH) transmissions or send Physical Uplink Shared Channel (PUSCH) transmissions based on one or more DCI fields of the decoded PDCCH transmission.

[0007] In some representative embodiments, the WTRU may include circuitry comprising a processor, a transmit / receive unit, and / or a storage unit. The transmit / receive unit may be configured to receive information indicating the configuration of a CORESET (Control Resource Set), the CORESET configuration including indications of symbol duration and / or physical downlink control channel (PDCCH) demodulation reference signal (DM-RS) frequency hopping or density changes. The transmit / receive unit may be configured to receive information indicating the search space configuration of a search space associated with the CORESET, the search space configuration including one or more downlink control information (DCI) formats to be monitored and / or one or more aggregation levels associated with each of the one or more DCI formats. The processor may be configured to determine one or more DM-RS locations in one or more resource element groups (REGs) of the CORESET and / or the search space associated with the CORESET. The transmit / receive unit may be configured to receive PDCCH transmissions in the search space associated with the CORESET. The processor may be configured to decode the received PDCCH transmissions using one or more PDCCH DM-RS locations determined from the one or more DM-RS locations. The processor and transmit / receive unit may be further configured to receive physical downlink shared channel (PDSCH) transmissions or transmit physical uplink shared channel (PUSCH) transmissions based on one or more DCI fields of the decoded PDCCH transmissions.

[0008] In some representative implementations, WTRU may determine the location of one or more DM-RS in one or more REGs of the CORESET and / or the search space associated with the CORESET in time and / or frequency based on: (1) any of the indication, symbol duration, one or more DCI formats and / or one or more aggregation levels; and (2) the corresponding REG index of each REG in one or more REGs.

[0009] In some representative implementations, the resource element group (REG) of the CORESET and / or the search space associated with the CORESET may include a first REG and a second REG. One or more DM-RS locations of the first REG may differ in the frequency domain from one or more DM-RS locations of the second REG.

[0010] In some representative implementations, the first REG and the second REG may belong to the same REG bundle.

[0011] In some representative implementations, the CORESET configuration may include an indication of symbol duration and / or PDCCH DM-RS density variation.

[0012] In some representative implementations, the resource element group (REG) of the CORESET and / or the search space associated with the CORESET may include a first REG and a second REG. One or more DM-RS locations may each appear in the first REG in the time domain, and one or more DM-RS locations may not appear in the second REG.

[0013] In some representative implementations, the first REG and the second REG may be associated with the same REG bundle.

[0014] In some representative implementations, the first REG may correspond to the first symbol of the same REG bundle in the time domain.

[0015] In some representative implementations, the CORESET configuration may include indications of symbol duration and / or PDCCH DM-RS frequency hopping.

[0016] In some representative implementations, one or more REGs may be associated with the same control channel element (CCE). Attached Figure Description

[0017] Figure 1A This is a system diagram illustrating an exemplary communication system that can be implemented in one or more of the disclosed embodiments;

[0018] Figure 1B This illustrates that, according to one implementation scheme, it is possible to Figure 1A A system diagram of an exemplary wireless transmit / receive unit (WTRU) used within the communication system shown;

[0019] Figure 1C This illustrates that, according to one implementation scheme, it is possible to Figure 1A A system diagram of an exemplary radio access network (RAN) and an exemplary core network (CN) used within the communication system shown;

[0020] Figure 1D This illustrates that, according to one implementation scheme, it is possible to Figure 1A A system diagram of another exemplary RAN and another exemplary CN used in the communication system shown;

[0021] Figure 2 The frequencies available in various countries range between 52.6 GHz and 71 GHz.

[0022] Figure 3 The frequencies available in various countries are shown, ranging from 71 GHz to 100 GHz.

[0023] Figure 4Examples of phase noise are shown by comparing the curves of the common power spectral density as a function of frequency offset at 4 GHz, 30 GHz, and 70 GHz, and on the right is an example of a group of received symbols with phase noise for the received signal at high frequencies (e.g., above 52.6 GHz).

[0024] Figure 5 An exemplary set of parameters in NR is shown.

[0025] Figure 6 Examples of front-end DM-RS and additional DM-RS are shown.

[0026] Figure 7 Examples of the preceding DM-RS for Type 1 and Type 2 single-symbol DM-RS are shown.

[0027] Figure 8 An example of a type 1 double-symbol DM-RS with a preceding DM-RS is shown.

[0028] Figure 9 An example of a type 2 double-symbol DM-RS with a preceding DM-RS is shown.

[0029] Figure 10 An example of the NR PDCCH structure is shown.

[0030] Figure 11 An example comparing RS densities in the time and frequency domains is shown when SCS is twice as large.

[0031] Figure 12 An example of an additional DM-RS configuration based on the CSI-RS resource set is shown.

[0032] Figure 13 An example of an additional DM-RS with an AP CSI-RS for PDSCH decoding is shown.

[0033] Figure 14 An example of an additional DM-RS with an AP CSI-RS for PUSCH decoding is shown.

[0034] Figure 15 An example of an additional DM-RS with SP CSI-RS is shown.

[0035] Figure 16 An example of CSI reporting configuration for an additional DM-RS based on CSI-RS is shown.

[0036] Figure 17 An exemplary configuration for an additional DM-RS based on an SRS resource set is shown.

[0037] Figure 18An example of an additional DM-RS with an AP SRS for PUSCH is shown.

[0038] Figure 19 This is an example of an additional DM-RS with SP SRS for PDSCH decoding.

[0039] Figure 20 An example of an additional DM-RS with DCI is shown.

[0040] Figure 21 An example of an additional DM-RS with a MAC CE is shown.

[0041] Figure 22 An example of a defined antenna port indication table for higher density DM-RS is shown.

[0042] Figure 23 This is an example of an antenna port indicator table used for normal density and higher density DM-RS based on the antenna port indicator table.

[0043] Figure 24 An example of higher DM-RS density with single-symbol type 1DM-RS is shown.

[0044] Figure 25 An example of DM-RS sequence mapping with single symbol type 1DM-RS is shown.

[0045] Figure 26 An exemplary pattern #1 with a higher DM-RS density and dual-symbol type 1DM-RS is shown.

[0046] Figure 27 An exemplary pattern #2 with a higher DM-RS density and dual-symbol type 1DM-RS is shown.

[0047] Figure 28 An example of DM-RS sequence mapping with dual symbol type 1DM-RS is shown.

[0048] Figure 29 An example of higher DM-RS density with single-symbol type 2DM-RS is shown.

[0049] Figure 30 An example of DM-RS sequence mapping with single symbol type 2DM-RS is shown.

[0050] Figure 31 An example of higher DM-RS density with dual-symbol type 2DM-RS is shown.

[0051] Figure 32 An example of DM-RS sequence mapping with dual symbol type 2DM-RS is shown.

[0052] Figure 33 An example of a higher-density DM-RS with a single-symbol type 1DM-RS employing adjacent symbols is shown.

[0053] Figure 34 An example of a higher-density DM-RS with a single-symbol type 1DM-RS employing non-adjacent symbols is shown.

[0054] Figure 35 An example of a higher-density DM-RS with a single-symbol type 2DM-RS employing adjacent symbols is shown.

[0055] Figure 36 An example of a higher-density DM-RS with a single-symbol type 2DM-RS employing non-adjacent symbols is shown.

[0056] Figure 37 This is an example of frequency hopping with an additional DM-RS having a single-symbol type 1DM-RS.

[0057] Figure 38 This is an example of frequency hopping with an additional DM-RS having a single-symbol type 2DM-RS.

[0058] Figure 39 This is an example of DM-RS port aggregation for single-symbol type 1DM-RS.

[0059] Figure 40 An example of a PT-RS above 52.6 GHz is shown to provide enhanced channel estimation performance in the frequency domain.

[0060] Figure 41 An example of frequency hopping for PDCCH DM-RS is shown.

[0061] Figure 42 An example of a REG used to enhance PDCCH DM-RS is shown.

[0062] Figure 43 This is an example of PDCCH DM-RS skipping utilizing enhanced PDCCH DM-RS.

[0063] Figure 44 Examples of PUCCH DM-RS with enhanced DM-RS frequency density and another example of PUCCH DM-RS without enhancement are shown.

[0064] Figure 45 This is an example of frequency hopping in PUCCH DM-RS.

[0065] Figure 46This is an example of PUCCH DM-RS skipping and PUCCH DM-RS with enhanced DM-RS frequency density.

[0066] Figure 47 This is an exemplary process that can be implemented by WTRU for decoding PDDCH transmissions with DM-RS using frequency hopping or density variation.

[0067] Figure 48 This is an exemplary process that can be implemented by a RAN entity for transmitting PDDCH transmissions with DM-RS using frequency hopping or density variation.

[0068] Figure 49 This is an exemplary procedure that can be implemented by WTRU to trigger DM-RS enhancements for PDSCH and / or PUSCH transmissions.

[0069] Figure 50 This is an exemplary procedure that can be implemented by a RAN entity to trigger DM-RS enhancements at the WTRU for PDSCH and / or PUSCH transmissions.

[0070] Figure 51 This is an exemplary process that can be implemented by a WTRU for receiving PDSCH transmissions using modulation and coding scheme (MCS) thresholds and DM-RS frequency hopping.

[0071] Figure 52 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using MCS thresholds and DM-RS frequency hopping.

[0072] Figure 53 This is an exemplary process that can be implemented by WTRU for sending PUSCH transmissions using MCS thresholds and DM-RS frequency hopping.

[0073] Figure 54 This is an exemplary process that can be implemented by a RAN entity for receiving PUSCH transmissions using MCS thresholds and DM-RS frequency hopping.

[0074] Figure 55 This is an exemplary procedure that can be implemented by a WTRU for receiving PDSCH transmissions using a subcarrier spacing (SCS) threshold and DM-RS frequency hopping.

[0075] Figure 56 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using SCS thresholds and DM-RS frequency hopping.

[0076] Figure 57 This is an exemplary process that can be implemented by a WTRU for sending PUSCH transmissions using SCS thresholds and DM-RS frequency hopping.

[0077] Figure 58 This is an exemplary process that can be implemented by a RAN entity for receiving PUSCH transmissions using SCS thresholds and DM-RS frequency hopping.

[0078] Figure 59 This is an exemplary process that can be implemented by a WTRU for receiving PDSCH transmissions aggregated using DM-RS ports.

[0079] Figure 60 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using DM-RS port aggregation.

[0080] Figure 61 This is an exemplary process that can be implemented by WTRU for sending PUSCH transmissions using DM-RS port aggregation.

[0081] Figure 62 This is an exemplary process that can be implemented by a RAN entity for receiving PUSCH transmissions aggregated using DM-RS ports.

[0082] Figure 63 This is an exemplary process that can be implemented by a WTRU for receiving PDSCH transmissions using a higher density DM-RS.

[0083] Figure 64 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using higher density DM-RS.

[0084] Figure 65 This is an exemplary process that can be implemented by WTRU for sending PUSCH transmissions using higher density DM-RS.

[0085] Figure 66 This is an exemplary process that can be implemented by a RAN entity for receiving PDSCH transmissions using higher density DM-RS.

[0086] Figure 67 This is an exemplary process that can be implemented by WTRU for decoding PDDCH transmissions with DM-RS using frequency hopping or density variation.

[0087] Figure 68 This is an exemplary process that can be implemented by a RAN entity for transmitting PDDCH transmissions with DM-RS using frequency hopping or density variation. Detailed Implementation

[0088] Exemplary network for implementing the implementation scheme

[0089] Figure 1AThis is a schematic diagram illustrating an exemplary communication system 100 that can be implemented in one or more of the disclosed embodiments. Communication system 100 can be a multiple access system providing content such as voice, data, video, messaging, and broadcasting to multiple wireless users. Communication system 100 enables multiple wireless users to access such content through the sharing of system resources (including wireless bandwidth). For example, 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 Extended OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), etc.

[0090] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, Public Switched Telephone Network (PSTN) 108, Internet 110, and other networks 112. However, 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, and 102d may be any type of device configured to operate and / or communicate in a wireless environment. As examples, WTRUs 102a, 102b, 102c, and 102d (any 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 (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of UEs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs.

[0091] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106 / 115, Internet 110, and / or other networks 112. As an example, base stations 114a and 114b may be base transceiver stations (BTS), Node Bs, evolved Node Bs, home Node Bs, home evolved Node Bs, gNBs, NR Node Bs, site controllers, access points (APs), wireless routers, etc. Although base stations 114a and 114b are each depicted as a single element, it should be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0092] 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 radio 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 radio services to a specific geographic area, which may be relatively fixed or changeable over time. A cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in an 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 desired spatial directions.

[0093] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0094] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 / 113 may implement radio technologies 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).

[0095] In the implementation scheme, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which can use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish air interface 116.

[0096] In the implementation scheme, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can use New Radio (NR) to establish air interface 116.

[0097] In the implementation scheme, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can, for example, use a dual connectivity (DC) principle to implement both LTE and NR radio access together. Therefore, the air interface utilized by WTRUs 102a, 102b, and 102c can be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0098] In other implementations, base station 114a and WTRUs 102a, 102b, and 102c can implement radio technologies such as IEEE 802.11 (i.e., WiFi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Enhanced Data Rate Evolution (EDGE), and GSM EDGE (GERAN).

[0099] Figure 1A Base station 114b can be, for example, a wireless router, a home node B, a home evolution node B, or an access point, and can utilize any suitable RAT to facilitate wireless connectivity in localized areas such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for use by drones), roads, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0100] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although not explicitly stated... Figure 1AAs shown, but it should be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT as RAN 104 / 113 or a different RAT. For example, in addition to being connected to RAN 104 / 113 which can utilize NR radio technology, CN 106 / 115 can also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0101] CN 106 / 115 may also act as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 113 or a different RAT.

[0102] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, Figure 1A The WTRU 102c shown can be configured to communicate with a base station 114a that can employ cellular-based radio technology and with a base station 114b that can employ IEEE 802 radio technology.

[0103] Figure 1B This is a system diagram illustrating an exemplary WTRU 102. (See diagram below.) Figure 1B As shown, WTRU 102 may include a processor 118, a transceiver 120, a transmitting / receiving element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, etc. It should be understood that, while remaining consistent with the implementation, WTRU 102 may include any sub-combination of the foregoing elements.

[0104] Processor 118 can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 can be coupled to transceiver 120, which can be coupled to transmitting / receiving element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it should be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0105] Transmitting / receiving element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, transmitting / receiving element 122 may be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 may be configured to transmit and / or receive RF and optical signals. It should be understood that transmitting / receiving element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0106] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmitting / receiving elements 122. More specifically, WTRU 102 may employ MIMO technology. Therefore, in one embodiment, WTRU 102 may include two or more transmitting / receiving elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via air interface 116.

[0107] Transceiver 120 can be configured to modulate signals transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As noted above, WTRU 102 may have multi-mode capability. For example, transceiver 120 may therefore include multiple transceivers to enable WTRU 102 to communicate via various RATs (such as NR and IEEE 802.11).

[0108] The processor 118 of 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) 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, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 may access information from any type of suitable memory (such as non-removable memory 130 and / or removable memory 132) and store data in any type of suitable memory. 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. Removable memory 132 may include a user identity module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 may access information from memory that is not physically located on WTRU 102 (such as on a server or home computer (not shown)) and store data in that memory.

[0109] The processor 118 may receive power from the 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, fuel cells, etc.

[0110] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to or instead of the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via 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, while remaining consistent with the implementation, the WTRU 102 may acquire location information using any suitable location determination method.

[0111] The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral device 138 may include an accelerometer, electronic compass, satellite transceiver, digital camera (for photos and / or video), Universal Serial Bus (USB) port, vibration device, television transceiver, hands-free headset, etc. Modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral devices 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0112] WTRU 102 may include a full-duplex radio for which the transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference through signal processing via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include a half-duplex radio for which the transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0113] Figure 1C This is a system diagram illustrating RAN 104 and CN 106 according to one embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0114] RAN 104 may include evolved Nodes B 160a, 160b, and 160c; however, it should be understood that RAN 104 may include any number of evolved Nodes B while remaining consistent with the implementation scheme. Evolved Nodes B 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In the implementation scheme, evolved Nodes B 160a, 160b, and 160c may implement MIMO technology. Therefore, evolved Node B 160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a.

[0115] Each of the evolved nodes B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, and user scheduling in the UL and / or DL, etc. Figure 1C As shown, evolution nodes B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0116] 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.

[0117] The MME 162 can connect to each of the evolved nodes B 162a, 162b, and 162c in RAN 104 via the S1 interface and can be used as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0118] The SGW 164 can connect to each of the evolved Nodes B 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 typically routes and forwards user data packets to and from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during inter-evolved Node B handovers, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c.

[0119] SGW 164 can be connected to PGW 166, which provides WTRU 102a, 102b, 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0120] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRUs 102a, 102b, and 102c with access to a circuit-switched network (such as PSTN 108) to facilitate communication between WTRUs 102a, 102b, and 102c and conventional landline communication equipment. For example, CN 106 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and PSTN 108, or be able to communicate with such an IP gateway. Additionally, CN 106 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0121] Despite WTRU in Figures 1A to 1D While described as a wireless terminal, it is conceivable that in some representative implementations, such a terminal may (e.g., temporarily or permanently) use a wired communication interface with a communication network.

[0122] In a representative implementation, the other network 112 may be a WLAN.

[0123] A WLAN in Basic Services Set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic out of the BSS. Traffic originating outside the BSS and destined for a STA can reach and be delivered to the STA via the AP. Traffic originating from a STA and destined for a destination outside the BSS can be sent to the AP for delivery to the appropriate destination. Traffic between STAs within the BSS can be sent via the AP, for example, where a source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as point-to-point traffic. Point-to-point traffic can be sent between source and destination STAs (e.g., directly between them) using Direct Link Establishment (DLS). In some representative implementations, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). WLANs using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as the "ad-hoc" communication mode in this document.

[0124] When operating in 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of fixed width (e.g., a 20 MHz wide bandwidth) or 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 implementations, such as in an 802.11 system, Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) can be implemented. For CSMA / CA, 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 STA can back off. A single STA (e.g., only one station) can transmit at any given time within a given BSS.

[0125] High-throughput (HT) STAs can communicate using a 40MHz wide channel, for example, by combining a primary 20MHz channel with adjacent or non-adjacent 20MHz channels to form a 40MHz wide channel.

[0126] The Very High Throughput (VHT) STA supports channels with widths of 20MHz, 40MHz, 80MHz, and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining consecutive 20MHz channels. A 160MHz channel can be formed by combining eight consecutive 20MHz channels, or by combining two non-consecutive 80MHz channels (this can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, data can be processed by a segment parser that can split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed separately on each stream. These streams can be mapped to two 80MHz channels, and data can be transmitted via the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration can be reversed, and the combined data can be sent to Media Access Control (MAC).

[0127] 802.11af and 802.11ah support operating modes below 1 GHz. Compared to those used in 802.11n and 802.11ac, 802.11af and 802.11ah reduce channel operating bandwidth and carrier. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative implementations, 802.11ah may support instrument-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support (e.g., only support) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain a very long battery life).

[0128] WLAN systems supporting multiple channels, as well as channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include channels that can be designated as primary channels. A primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by STAs operating in the BSS (each supporting a minimum bandwidth operating mode). In the 802.11ah example, for STAs supporting (e.g., only supporting) a 1MHz mode (e.g., MTC type devices), the primary channel can be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier Sense and / or Network Allocation Vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy, for example, because an STA (supporting only the 1MHz operating mode) is transmitting to the AP, the entire available band can be considered busy even if most of the band remains idle and potentially available.

[0129] In the United States, the available frequency bands for 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total available bandwidth for 802.11ah ranges from 6MHz to 26MHz, depending on the country code.

[0130] Figure 1D This is a system diagram illustrating RAN 113 and CN 115 according to one implementation scheme. As noted above, RAN 113 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0131] RAN 113 may include gNBs 180a, 180b, and 180c; however, it should be understood that RAN 113 may include any number of gNBs while remaining consistent with the implementation scheme. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communication with WTRUs 102a, 102b, and 102c via air interface 116. In the implementation scheme, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, gNB 180a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In the implementation scheme, gNBs 180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In the implementation scheme, gNBs 180a, 180b, and 180c can implement Cooperative Multipoint (CoMP) technology. For example, WTRU 102a can receive cooperative transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0132] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with an scalable set of parameters. For example, OFDM symbol spacing and / or OFDM subcarrier spacing can vary depending on different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing different numbers of OFDM symbols and / or continuously varying absolute time lengths).

[0133] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., evolved Node Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate or connect to gNBs 180a, 180b, and 180c, and also communicate or connect to other RANs (such as evolved Node Bs 160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more evolved Node Bs 160a, 160b, and 160c. In a non-standalone configuration, evolved Node Bs 160a, 160b, and 160c can be used as mobility anchors 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.

[0134] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing of user plane data to User Plane Functions (UPF) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0135] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0136] AMF 182a and 182b can connect to one or more of the gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can be used as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF 183a and 183b, managing registration areas, terminating NAS signaling, mobility management, etc. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the type of service used by WTRU 102a, 102b, and 102c. For example, different network slices can 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 services for Machine Type Communication (MTC) access. The AMF162 can provide control plane functions for handover between 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.

[0137] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure traffic routing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0138] UPF 184a and 184b can connect via the N3 interface to one or more of the gNBs 180a, 180b, and 180c in RAN 113. These gNBs can provide WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0139] CN 115 may facilitate communication with other networks. For example, CN 115 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 115 and PSTN 108, or may communicate with such an IP gateway. Additionally, CN 115 may provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In an embodiment, WTRUs 102a, 102b, and 102c may be connected to DNs 185a and 185b via UPFs 184a and 184b through their N3 interfaces and their N6 interfaces with local data networks (DNs) 185a and 185b.

[0140] Given Figures 1A to 1D as well as Figures 1A to 1D The corresponding descriptions herein refer to one or more of the functions described below, which may be performed by one or more emulation devices (not shown): WTRU102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device described herein. An emulation device may be one or more devices configured to mimic one or more of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0141] Simulation devices can be designed to perform one or more tests on other devices in laboratory and / or carrier network environments. For example, the one or more simulation devices may perform one or more 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. The one or more simulation devices may perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. Simulation devices may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communication to perform tests.

[0142] The one or more simulation devices may 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 devices may be used in test scenarios within a test laboratory and / or non-deployed (e.g., testing) wired and / or wireless communication networks to perform testing of one or more components. The one or more simulation devices may be test equipment. Direct RF coupling and / or wireless communication via an RF circuit system (e.g., which may include one or more antennas) may be used by the simulation devices to transmit and / or receive data.

[0143] New radio (NR) may exceed 52.6 GHz. For unlicensed operation, at least 5 GHz of globally available spectrum may exist (e.g., between 57 GHz and 64 GHz). For unlicensed operation, a maximum of 14 GHz of available spectrum may exist (e.g., between 57 GHz and 71 GHz in some countries). For licensed operation, at least 10 GHz of globally available spectrum may exist, for example, between 71 GHz and 76 GHz and between 81 GHz and 86 GHz. For licensed operation, a maximum of 18 GHz of available spectrum may exist (e.g., between 71 GHz and 114.25 GHz in some countries). Frequency ranges above 52.6 GHz may include larger spectrum allocations and larger bandwidths that are unavailable for bands below 52.6 GHz. The physical layer channels of NR can be optimized for use below 52.6 GHz.

[0144] Figure 2 Table 200 shows the frequencies available in various countries between 52.6 GHz and 71 GHz.

[0145] Figure 3 Table 300 shows the frequencies available in various countries between 71 GHz and 100 GHz.

[0146] For example, frequencies above 52.6 GHz may have higher phase noise, greater propagation loss due to high atmospheric absorptivity, lower power amplifier efficiency, and stronger power spectral density tuning requirements compared to lower frequency bands. Phase noise can increase with carrier frequency.

[0147] Figure 4 On the left, curves showing the common power spectral density as a function of frequency offset at 4 GHz, 30 GHz, and 70 GHz illustrate examples of phase noise, while on the right, examples of received symbol groups with phase noise for received signals at high frequencies (e.g., above 52.6 GHz) are shown.

[0148] NR can use scalable subcarrier spacing (SCS) to mitigate phase noise in frequency range 2 (FR2). FR2 can represent a frequency range from 24.25 GHz to 52.6 GHz. The scalable SCS can be represented as f c =15·2 n [kHz], where f c It can be an SCS and n can be a non-negative integer. Scalable SCS allows the cyclic prefix (CP) length to be inversely proportional to the symbol length and allows symbol boundary alignment between different SCSs. FR2 supports 120 / 240kHz SCS values. Frequency Range 1 (FR1) supports 15 / 30 / 60kHz SCS values. FR1 can represent a frequency range from 450MHz to 6000MHz (e.g., ...). Figure 5 (As shown).

[0149] Figure 5 Table 500 shows an exemplary set of parameters in NR.

[0150] Phase noise can be a random process that directly affects the up / down switching between baseband and RF signals, for example, due to the time instability of the local oscillator. Phase noise in the frequency domain can cause signal jitter in the time domain. Phase noise can be modeled as a constant and can be compensated for, for example, by estimation when the phase change rate is slow (e.g., relative to the OFDM symbol duration). Estimation and correction of phase noise can become difficult, for example, when the phase change rate is fast (e.g., relative to the OFDM symbol duration). The larger the SCS (Sequence of Controlled Components), the easier it is to compensate for phase noise. The effect of phase noise can increase with increasing modulation. For example, as modulation increases, the phase difference between each modulation point can become smaller. A smaller phase difference increases the probability of incorrectly decoding the modulation with the same amount of phase noise.

[0151] As the carrier frequency increases, signal propagation exhibits less multipath delay spread, for example, due to the sharp beamforming via MIMO antennas and due to the signal propagation characteristics at higher frequencies. Longer CP becomes less significant at higher carrier frequencies. FR2 may (e.g., therefore only) support 60 / 120kHz SCS options.

[0152] NR can be adapted (e.g., using NR waveforms) to support operation between 52.6 GHz and 71 GHz, as well as channel access mechanisms for, for example, beam-based operation of unlicensed spectrum between 52.6 GHz and 71 GHz.

[0153] NR can support a variety of reference signals (RS).

[0154] Demodulation Reference Signal (DM-RS) can be supported in NR. DM-RS can be a special type of physical layer signal. DM-RS can be used as an RS for decoding the Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH). DM-RS can be WTRU-specific. DM-RS can be used to estimate precoded radio channels for PDSCH (e.g., by WTRU 102a-d) and PUSCH (e.g., by gNB 180a-c).

[0155] Channel State Information-Reference Signal (CSI-RS) is supported in NR. WTRU can use CSI-RS to measure radio channel quality (e.g., Channel State Information (CSI)) and report the measurement results (e.g., to gNB 180a-c).

[0156] Detection Reference Signal (SRS) is supported in NR. gNB 180a-c can use SRS to identify the channel / beam information of the UL.

[0157] Synchronization Signal Blocks (SSBs) are supported in NR. WTRU 102a-d can perform cell search and coarse synchronization based on SSBs. SSBs may include the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH).

[0158] Tracking RS (TRS) is supported in NR. WTRU 102a-d can (e.g., in LTE and NR) be coarsely synchronized to the base station based on synchronization signals (e.g., PSS and SSS). For example, coarse synchronization may not be sufficient for high modulation (e.g., 64QAM or 256QAM) because high modulation can be very sensitive to time / frequency offsets. WTRU can (e.g., in LTE) perform fine time / frequency synchronization for gNB 180a-c, for example, based on normally open RS (e.g., common RS (CRS)). NR (e.g., in contrast to LTE) may not provide normally open RS such as CRS to offer more flexibility. NR can support flexible RS (e.g., TRS) to provide fine synchronization for time / frequency.

[0159] PT-RS is supported in NR. Phase noise can increase with carrier frequency. FR2 may experience more phase noise than FR1. NR can support PT-RS with configurable time density, frequency density, and resource element (RE) offset, for example, to mitigate phase noise in FR2.

[0160] Location RS (PRS) can be supported in NR.

[0161] Remote interference measurement (RS) is supported in NR.

[0162] The DM-RS can be used for channel sharing. As described above, the DM-RS can be a special type of physical layer signal used as the RS for decoding PDSCH and PUSCH. The DM-RS can be WTRU-specific. The DM-RS can be used to estimate the precoded radio channels of PDSCH (e.g., by WTRU102a-d, or referred to herein as WTRU 102) and PUSCH (e.g., by gNB 180a-c, or referred to herein as gNB 180). The gNB 180 can (e.g., for PDSCH) beamform the DM-RS, keeping it within the scheduled resources, and can transmit it, for example, if necessary. The gNB 180 can (e.g., for PUSCH) indicate the precoded channel information via SRI (Probe Reference Signal Resource Indicator). The WTRU 102 can (e.g., based on the indication) beamform the DM-RS within the scheduled resources.

[0163] Multiple orthogonal DM-RS ports can be allocated to support single-user (SU) / multi-user (MU) MIMO transmissions. In one example, multiple orthogonal DM-RS ports (e.g., one of them) can be used for the transport layer of transmitting / decoding PDSCH or PUSCH. The WTRU102 and / or gNB 180 can (e.g., in NR) support, for example, up to 12 DM-RS ports for MU MIMO transmissions, while the WTRU102 and / or gNB 180 can support up to 8 DM-RS ports for DL ​​SU MIMO transmissions and 4 DM-RS ports for UL SU MIMO transmissions, respectively.

[0164] DM-RS may include a front DM-RS and an additional DM-RS. Figure 6 An example of a time slot 600 with a pre-dial DM-RS 602 and an additional DM-RS 604 is shown. The pre-dial DM-RS 602 can be located before the scheduled time slot, such as the first OFDM symbol of the scheduled time slot (e.g., PDSCH mapping type B) or the first OFDM symbol after PDCCH 606 ​​(e.g., PDSCH type mapping A). The pre-dial DM-RS 602 enables early channel estimation for low-latency applications. The pre-dial DM-RS 602 may be insufficient to obtain accurate channel state information, especially in high-mobility scenarios. For example, by increasing the transmission rate of the DM-RS signal (e.g., by configuring an additional DM-RS), the gNB 180 can track rapid changes in the wireless channel in high-mobility scenarios.

[0165] Multiple types of DM-RS can exist. In one example, one or two symbols can be used to support two types of front DM-RS, for example, Figure 7 , Figure 8 and Figure 9As shown. In one example (e.g., type 1 DM-RS), a DM-RS port can be mapped to (e.g., one) subcarrier of each second subcarrier in a DM-RS symbol, which can form a comb pattern (e.g., comb #0 or comb #1). (e.g., one) subcarrier can be referred to as a resource element (RE). (e.g., each) comb pattern can support (e.g., up to) two DM-RS ports (e.g., using one symbol) and / or four DM-RS ports (e.g., using two symbols) for example by utilizing code division multiplexing (CDM). Type 2 DM-RS (e.g., the opposite of type 1 DM-RS) can be based on frequency domain code division multiplexing (FD-CDM). One or two symbols can be allocated (e.g., for type 2 DM-RS) for three CDM groups (e.g., CDM group #0, CDM group #1, CDM group #2). In one example, each of the three CDM groups can include two pairs of two consecutive REs in the frequency domain. In one example, each of the three CDM groups can support (e.g., at most) two DM-RS ports with one symbol and four DM-RS ports with two symbols (e.g., by utilizing CDM).

[0166] Compared to Type 2 DM-RS (e.g., four REs), Type 1 DM-RS can allocate more REs per DM-RS port (e.g., six REs). Type 1 DM-RS can provide better channel estimation accuracy. For example, due to the larger number of RE allocations (e.g., for Type 1 DM-RS), a limited number of orthogonal multiplexing operations can be supported (e.g., four ports per OFDM symbol and up to eight ports with two OFDM symbols). Type 2 DM-RS (e.g., the opposite of Type 1 DM-RS) can provide poorer channel estimation accuracy (e.g., due to lower RS ​​density). Type 2 DM-RS can (e.g., the opposite of Type 1 DM-RS) provide greater utilization of orthogonal DM-RS ports (e.g., six ports per symbol and up to 12 ports with two symbols).

[0167] Figure 7 Examples of pre-DM-RS for Type 1 700 and Type 2 single-symbol DM-RS 702 are shown.

[0168] Figure 8 An example of a front DM-RS for a Type 1 dual-symbol DM-RS 800 is shown.

[0169] Figure 9 An example of a pre-DM-RS for a Type 2 dual-symbol DM-RS 900 is shown.

[0170] For example, by increasing the transmission rate of the DM-RS signal (e.g., by utilizing an additional DM-RS), the gNB 180 can (e.g., in high-mobility scenarios) track rapid changes in the channel. The number of symbols used for the additional DM-RS can be, for example, three symbols (e.g., four symbols including both the pre-DM-RS and the additional DM-RS) for a single-symbol DM-RS and two symbols (e.g., three symbols including both the pre-DM-RS and the additional DM-RS) for a dual-symbol DM-RS.

[0171] Figure 10 Example 1000 of NR PDCCH structure 1000 is shown.

[0172] The Physical Downlink Control Channel (PDCCH) is a physical channel that carries the Control Resource Set (CORESET) 1002, Resource Element Group (REG) 1004, Control Channel Element (CCE) 1006, and Search Space (SS) based on Downlink Control Information (DCI).

[0173] WTRU 102 can receive configurations of one or more CORESET 1002. CORESET 1002 may include one or more of the following: frequency allocation (e.g., as a block of six resource blocks (RBs), time length (e.g., one to three OFDM symbols), REG bundle type, and / or the type of mapping from REG bundle 1004 to CCE 1006 (e.g., whether it is interleaved or uninterleaved). For example, WTRU 102 may (e.g., in a bandwidth portion (BWP)) receive (e.g., up to) N (e.g., three) CORESET 1002. For example, 12 CORESETs may exist in four possible bandwidth portions.

[0174] WTRU 102 may receive the configuration of CORESET 1002 (e.g., CORESET 0) with index 0, for example, via a four-bit information element from the Master Information Block (MIB) of gNB 180. The configuration of CORESET 0 can be limited to a finite number of combinations of parameters compared to other CORESET 1002s. In one example, the configuration of CORESET 0 may not be aligned with the frequency grids of other CORESET 1002s.

[0175] REG 1004 can be the smallest building block of PDCCH 606. REG 1004 can, for example, consist of one OFDM symbol 1010 with respect to time and 12 REs 1008 on one RB with respect to frequency. In an exemplary REG 1004, nine REs 1008 can be used for control information, while three REs can be used for DM-RS. Multiple REG 1004s that are adjacent in time or frequency (e.g., 2, 3, and / or 6) can form a REG bundle. REG bundles can be used with the same precoder, and DM-RS for multiple REGs can be used together for channel estimation. In one example, six REGs (e.g., in the format of 1, 2, or 3 REG bundles) can form a CCE 1006, which can be the minimum possible PDCCH 606. PDCCH 606 ​​can include one or more CCE 1006s (e.g., 1, 2, 4, 8, and / or 16 CCEs). The quantity of CCE 1006 used for PDCCH 606 ​​can be referred to as the polymerization grade (AL) of PDCCH.

[0176] The mapping of REG bundles can be interleaved or non-interleaved. In an example of non-interleaved mapping, consecutive REG bundles (e.g., frequency-adjacent) can form CCE 1006, where frequency-adjacent CCE 1006 can form PDCCH 606. In an example of interleaved mapping, REG 1004 can be interleaved (e.g., or permuted) before being mapped to CCE 1006, which can result in (e.g., generally) a non-adjacent REG bundle 1004 in one CCE 1006 and a non-adjacent CCE 1006 in one PDCCH 606.

[0177] WTRU 102 can receive a synchronization signal (SS) or a configuration of SS sets (e.g., for multiple aggregation levels). SS or SS sets may include PDCCH candidate sets. WTRU 102 can, for example, monitor PDCCH candidate sets based on the PDCCH candidate sets.

[0178] WTRU 102 may determine, for example, the number of candidates for each aggregation level or for each aggregation level, and a set of monitoring opportunities, through one or more associated CORESETs. Monitoring opportunities may be determined, for example, through one or more of the following: monitoring periodicity (e.g., according to time slots), monitoring offset, and monitoring pattern (e.g., corresponding to 14 bits of a possible symbol pattern within a time slot).

[0179] The Physical Uplink Control Channel (PUCCH) is a physical channel that transmits uplink control information (UCI) such as HARQ feedback, Channel State Information (CSI) reports, and Scheduling Requests (SRs). In NR, the WTRU 102 can support one or more of the following PUCCH formats for transmitting UCI:

[0180]

[0181] While a large subcarrier spacing (SCS) can reduce phase noise, a large SCS can also degrade channel estimation performance, for example, due to the low density of RS in the frequency domain.

[0182] Figure 11 This shows the time domain when SCS is twice as large ( Figure 11 (shown in the middle horizontal direction) and frequency domain ( Figure 11 Example 1100 (shown vertically in the middle) compares the densities of RS 1102 and 1104.

[0183] In the example, the density of RS in the frequency domain can be inversely proportional to SCS, while the density of RS in the time domain can be directly proportional to SCS. In one example (e.g., as SCS increases), a lower frequency domain RS density may degrade the channel estimation performance of RS in the frequency domain, while (e.g., simultaneously) a higher time domain RS density may not provide a significant improvement in channel estimation performance in the time domain. RS can be enhanced for high SCS, for example, to maintain good channel estimation performance in the frequency domain.

[0184] Enhanced DM-RS channel estimation can be enabled for UL shared channels and downlink (DL) shared channels. Enhanced DM-RS channel estimation can also be enabled for DL ​​control channels and UL control channels.

[0185] Shared channel DM-RS enhancements can be provided. The WTRU 102 can determine, for example, whether to use additional DM-RS based on CSI-RS.

[0186] Additional DM-RSs, in addition to PDSCH DM-RS and / or PUSCH DM-RS, can be supported. These additional DM-RSs can be located in an SCS that does not have DM-RS ports for PDSCH and / or PUSCH, for example, to provide enhanced channel estimation performance in the frequency domain. In one example, additional DM-RS based on CSI-RS can be supported. Flexible configuration of CSI-RS resources and CSI-RS resource sets (e.g., RE locations, RS density, and bandwidth) can provide RE locations capable of enabling enhanced channel estimation of DM-RSs in the frequency domain.

[0187] The WTRU 102 can determine the additional DM-RS configuration, for example, based on the CSI-RS.

[0188] In one example, WTRU 102 may determine additional DM-RS configurations, for instance, based on the NZP CSI-RS resource set.

[0189] For example, WTRU 102 may receive one or more RRC messages that include multiple CSI-RS resource sets. The one or more RRC messages may indicate (e.g., based on multiple CSI-RS resource sets) a set of multiple CSI-RS resource sets for additional DM-RS configuration. For example, the one or more RRC messages may include (e.g., from multiple CSI-RS resource sets) additional DM-RS information from one or more CSI-RS resource sets, such as... Figure 12 As shown. WTRU 102 can (e.g., based on supplemental DM-RS information from one or more CSI-RS resource sets) receive explicit and / or implicit signaling to trigger supplemental DM-RS to receive PDSCH or transmit PUSCH. The configured name may differ from the supplemental DM-RS information. For example (e.g., additional and / or alternative to "supplemental DM-RS"), other terms such as supplemental DM-RS, frequency tracking RS, or CSI-RS-based DM-RS may be used to indicate / configure the same functionality.

[0190] Additional DM-RS configurations (e.g., based on one or more CSI-RS resource sets) may be used, supported, or permitted, for example, with at least one of the following limitations: subcarrier spacing, operating frequency band, DM-RS configuration type, WTRU capability, number of antenna ports, modulation order for associated channels, scheduling type, and / or CORESET type.

[0191] In an example of subcarrier spacing limitation, for instance, when the subcarrier spacing of a channel (e.g., a DL / UL physical channel) is greater than a threshold (e.g., X kHz), an additional DM-RS can be configured, used, or supported, where the threshold can be predefined or configured.

[0192] In an example of operating frequency band limitation, for instance, when the operating frequency band is above a threshold (e.g., Y GHz), an additional DM-RS can be configured, used, and / or supported, where the threshold can be predefined or configured.

[0193] In an example of DM-RS configuration type restrictions, for instance, when using the first DM-RS configuration type (e.g., type 2), additional DM-RS can be configured, used, and / or supported (e.g., otherwise, additional DM-RS may not be supported and / or used).

[0194] In the example where WTRU capability is used as a limitation, WTRU 102 can indicate whether it supports additional DM-RS.

[0195] In an example where the number of antenna ports used for CSI-RS is a limitation, for example, if the number of antenna ports of the CSI-RS resource is greater than a threshold (e.g., 4), the CSI-RS resource can be used as an additional DM-RS, where the threshold can be predefined or configured.

[0196] In an example where the modulation order used for the associated channel is a constraint, for example, if the modulation order used for the channel (e.g., PDSCH) is higher than a threshold, additional DM-RS can be used or supported.

[0197] In examples where the scheduling type is used as a constraint, additional DM-RS can be configured, used, and / or supported based on any of single-slot / multi-slot scheduling, slot binding, and / or scheduling scaling factor (F). For example, WTRU 102 can receive a DCI that schedules one or more transport blocks using single-slot scheduling without slot binding and / or with the scheduling scaling factor F=1, and additional DM-RS can be used. For example, WTRU 102 can receive a DCI that schedules one or more transport blocks using multi-slot scheduling, slot binding, and / or F>1, without using additional DM-RS.

[0198] In the example where the CORESET type is used as a limitation, additional DM-RS can be configured, used, and / or supported based on the CORESET type of the DCI received by WTRU 102 for scheduling PDSCH. For example, WTRU 102 can apply (e.g., use) additional DM-RS if the CORESET type indicates a CORESET with any of enhanced REG, DM-RS frequency hopping, and / or enhanced PDCCH DM-RS density.

[0199] Figure 12 Example 1200 of an additional DM-RS configuration based on the CSI-RS resource set is shown.

[0200] Subsequently, the CSI-RS, Measurement Reference Signal, Tracking Reference Signal (TRS), Probe Reference Signal (SRS), Phase Tracking Reference Signal (PTRS), Synchronization Block (SSB), and Additional DM-RS can be used interchangeably, consistent with one or more implementations. The CSI-RS resource set and SRS resource set can also be used interchangeably, consistent with one or more implementations.

[0201] Figure 13 Example 1300 with an additional DM-RS for PDSCH decoding of AP CSI-RS is shown.

[0202] WTRU 102 may determine the additional DM-RS 1302, for example, based on AP CSI-RS. In the example, additional DM-RS 1302 based on AP CSI-RS may be supported. For example, explicit AP CSI-RS triggering and / or implicit AP CSI-RS triggering (e.g., via a CSI request field) may be supported using UL DCI (e.g., in DCI format 0_0, DCI format 0_1, or DCI format 0_2) and / or DL ​​DCI (e.g., in DCI format 1_0, DCI format 1_1, and / or DCI format 1_2). WTRU 102 may receive a scheduling PDSCH from gNB 180 and indicate a DCI 1304 for AP CSI-RS triggering for the additional DM-RS. WTRU 102 may (e.g., based on DCI) receive and decode a PDSCH with additional DM-RS 1302.

[0203] WTRU 102 may determine the additional DM-RS 1302, for example, based on an explicit AP CSI-RS trigger in the DL DCI. For example, WTRU 102 may receive one or more RRC messages including multiple CSI-RS resource sets for the additional DM-RS 1302. The one or more RRC messages may indicate (e.g., based on multiple CSI-RS resource sets) a set of CSI-RS resource sets (e.g., within multiple CSI-RS resource sets) for the AP CSI-RS request for the additional DM-RS 1302. WTRU 102 may (e.g., based on this set of CSI-RS resource sets) receive a DCI 1304 that schedules a PDSCH and triggers one or more CSI-RS resource sets in that set. WTRU 102 may (e.g., based on the DCI) receive and decode a PDSCH with the additional DM-RS 1302.

[0204] WTRU 102 may determine additional DM-RS 1302, for example, based on the AP CSI-RS trigger in the CSI request field of DL DCI 1304. For example, WTRU 102 may receive one or more RRC messages that include multiple CSI reporting configurations and multiple CSI-RS resource sets. Each CSI reporting configuration (e.g., each of the multiple CSI reporting configurations) may be associated with one of the multiple CSI-RS resource sets. One or more RRC messages may (e.g., based on the multiple CSI reporting configurations and multiple CSI-RS resource sets) instruct a set of CSI reporting configurations among the multiple CSI reporting configurations to trigger an AP CSI report. WTRU 102 may (e.g., based on this set of CSI reporting configurations) receive DCI 1304 that schedules a PDSCH and triggers one or more CSI reporting configurations in this set of CSI reporting configurations. The number of reports for each CSI reporting configuration in the one or more CSI reporting configurations may indicate "none". WTRU 102 may (e.g., based on one or more CSI reporting configurations) determine the reception of one or more CSI-RS resource sets (e.g., associated with one or more CSI reporting configurations) for attaching DM-RS 1302. WTRU 102 may (e.g., based on one or more CSI-RS resource sets) receive PDSCH with attached DM-RS 1302.

[0205] Figure 14 Example 1400 is shown with an additional DM-RS for PUSCH decoding using an AP CSI-RS.

[0206] WTRU 102 may determine additional DM-RS 1402, for example, based on the AP CSI-RS trigger in the CSI request field of UL DCI 1404. For example, WTRU 102 may receive one or more RRC messages that include multiple CSI reporting configurations and multiple CSI-RS resource sets. Each CSI reporting configuration (e.g., each of the multiple CSI reporting configurations) may be associated with one of the multiple CSI-RS resource sets. One or more RRC messages may (e.g., based on the multiple CSI reporting configurations and multiple CSI-RS resource sets) instruct a set of CSI reporting configurations among the multiple CSI reporting configurations to trigger an AP CSI report. WTRU 102 may (e.g., based on this set of CSI reporting configurations) receive a DCI 1404 that schedules a PUSCH and triggers one or more CSI reporting configurations in this set of CSI reporting configurations. The number of reports for each CSI reporting configuration in the one or more CSI reporting configurations may indicate "none". WTRU 102 may (e.g., based on one or more CSI reporting configurations) determine reception of one or more CSI-RS resource sets (e.g., associated with one or more CSI reporting configurations) for attaching DM-RS 1402. WTRU 102 may (e.g., based on one or more CSI-RS resource sets) transmit a PUSCH with attaching DM-RS 1402.

[0207] Figure 15 Example 1500 with an additional DM-RS featuring SP CSI-RS is shown.

[0208] WTRU 102 can, for example, determine additional DM-RS 1502 based on semi-persistent (SP) CSI-RS.

[0209] WTRU 102 may determine the additional DM-RS 1502 based, for example, on SP CSI-RS activation / deactivation 1506. For example, WTRU 102 may receive one or more RRC messages including multiple CSI-RS resource sets for attaching DM-RS 1502. The one or more RRC messages may indicate a set of CSI-RS resource sets (e.g., among multiple CSI-RS resource sets) for attaching DM-RS 1502. WTRU 102 may (e.g., based on this set of CSI-RS resource sets) receive one or more MAC CE messages to activate / deactivate this set of CSI-RS resource sets. WTRU 102 may receive DCI 1504 scheduling PDSCH or PUSCH. WTRU 102 may (e.g., based on the activation of this set of CSI-RS resource sets) determine whether this set of CSI-RS resource sets is available for attaching DM-RS 1502. In one example, for instance, if the set of CSI-RS resources is activated in a time slot scheduled for PDSCH, WTRU 102 may receive the set of CSI-RS resources for attaching DM-RS.

[0210] WTRU 102 may determine whether to use additional DM-RS 1502, for example, based on one or more of the activation 1506 of SP CSI-RS, the modulation and coding scheme (MCS) of the data (e.g., PDSCH or PUSCH), and DCI.

[0211] In one example, the MCS of the scheduled PDSCH or PUSCH can be used by WTRU 102 to determine whether to use additional DM-RS 1502. For example, the set of CSI-RS resources can be activated, and the MCS of the scheduled PDSCH or PUSCH can be above a threshold. WTRU 102 can (e.g., based on activated and threshold-exceeding MCS) receive the set of CSI-RS resources (e.g., 1302, 1402, 1502) for additional DM-RS and / or the set of CSI-RS resources (e.g., 1302, 1402, 1502) for additional DM-RS can exist in the associated / scheduled PDSCH or PUSCH.

[0212] In one (e.g., additional and / or alternative) example, explicit signaling can be used to indicate the allocation of additional DM-RS. For example, the set of CSI-RS resources can be activated, and the DCI 1504 scheduling the PDSCH / PUSCH can indicate that the set of CSI-RS resources is received as additional DM-RS. WTRU 102 can (e.g., based on activation and indication) receive one or more CSI-RS resource sets as additional DM-RS, and / or the set of CSI-RS resources used for additional DM-RS can exist in the associated / scheduled PDSCH or PUSCH.

[0213] Figure 16 An example of CSI reporting configuration for an additional DM-RS based on CSI-RS is shown.

[0214] WTRU 102 may determine whether to use supplementary DM-RS (e.g., 1302, 1402, 1502) based, for example, on the CSI reporting configuration (e.g., reportQuantity = 'none'). In the example of supplementary DM-RS based on CSI-RS (e.g., 1302, 1402, 1502), CSI reporting may not be supported. For example, WTRU 102 may receive an RRC message that includes the number of reports in the CSI reporting configuration. WTRU 102 may (e.g., for receiving or transmitting supplementary DM-RS) receive an RRC message that includes a report quantity of "none", for example, as... Figure 16 As shown.

[0215] WTRU 102 can determine the CSI report used for additional DM-RS.

[0216] WTRU 102 can determine CSI reports for PDSCH transports with additional DM-RS. In one example, WTRU 102 can report CSI reports optimized for PDSCH transports with additional DM-RS. WTRU 102 can receive one or more RRC messages to configure optimized CSI reports with additional DM-RS. For example, WTRU 102 can receive RRC messages for one or more CSI report configurations that indicate optimized CSI reports with additional DM-RS. For example, if one or more CSI report configurations are configured, activated, and / or triggered, WTRU 102 can report optimized CSI reports (e.g., based on one or more CSI report configurations).

[0217] The WTRU 102 can determine the CQI based on the additional DM-RS.

[0218] CQI reports may support additional DM-RS, such as for optimized CSI reports with additional DM-RS. WTRU 102 may receive one or more RRC messages indicating a CQI report assuming additional DM-RS. For example, the parameter "reportQuantity" indicating "CQI with additional DM-RS" may be supported. The parameter "cqi-Table" indicating a CQI table for additional DM-RS may be supported. The parameter "cqi-Table" indicating a CQI table for additional DM-RS may include, for example, "table4". WTRU 102 may (e.g., based on the indication) report a CSI report, including a CQI report assuming additional DM-RS, for example via the Physical Uplink Control Channel (PUCCH) and / or PUSCH. WTRU 102 may (e.g., based on one or more RRC messages) assume DM-RS channel estimation performance with additional DM-RS. WTRU 102 may (e.g., based on assumptions) determine one or more CQIs that meet a specific block error rate (BLER) (e.g., 10%) and may report the CQIs to gNB 180. The one or more CQIs may include CQIs with and / or without DM-RS. For example, if WTRU 102 only reports CQIs with DM-RS, WTRU 102 may report a preference. For example, WTRU 102 may report “PDSCH without DM-RS” or “PDSCH with DM-RS.” WTRU 102 may (e.g., to support the reporting of CQIs with DM-RS) receive (e.g., further) one or more RRC messages (e.g., to measure channel estimation performance with DM-RS) including one or more CSI-RS resource sets.

[0219] In one example, the CQI can be derived, determined, and / or calculated, for example, based on the DM-RS density configured, determined, and / or used for the corresponding physical channel (e.g., PDSCH). For example, the CQI_offset can be used to adjust the determined CQI value without considering the DM-RS density. The CQI_offset value can be determined, for example, based on the DM-RS density. One or more of the following can be applied.

[0220] The CQI_offset can be used to adjust the determined CQI value without considering the DM-RS density. For example, a first CQI value can be determined based on a measured reference signal. A second CQI can be determined as a function of the first CQI value. The CQI_offset can be determined based on the DM-RS density (e.g., second CQI value = first CQI value - CQI_offset). The second CQI value can be reported. The first CQI value can be referred to as a first type of CQI (e.g., and / or referred to as a normal CQI), while the second CQI value can be referred to as a second type of CQI (e.g., and / or referred to as a DM-RS density-related CQI). For example, when the DM-RS density is low, the CQI_offset value can be large. The CQI_offset value can be configured, for example, according to the DM-RS density level.

[0221] DM-RS density may be based on at least one of the following: (i) whether additional DM-RS is used; (ii) the number of OFDM symbols used for DM-RS; (iii) the DM-RS configuration type (e.g., type 1 or type 2); (iv) the subcarrier spacing; and / or (v) the operating frequency band.

[0222] The gNB 180 can be configured or dynamically indicated which type of CQI to use (e.g., normal CQI or DM-RS density-related CQI).

[0223] WTRU 102 can determine additional DM-RS patterns. For example, for an optimized CSI report with additional DM-RS, WTRU 102 recommendations for additional DM-RS patterns can be supported. WTRU 102 can receive one or more RRC messages indicating WTRU 102 recommendations for additional DM-RS patterns. For example, the parameter "reportQuantity" indicating "Additional DM-RS Pattern Index (ADPI)" can be supported. Other parameter names can be used, such as, but not limited to, DM-RS Pattern Index (DPI), DM-RS Index (DRI), etc. WTRU 102 can (e.g., based on the indication) receive one or more RRC messages that may include multiple CSI-RS resource sets, for example, as candidates for additional DM-RS patterns. WTRU 102 can (e.g., based on multiple CSI-RS resource sets) determine (e.g., from multiple CSI-RS resource sets) one or more CSI-RS resource sets and report the determined one or more CSI-RS resource sets to gNB 180. For example, when WTRU 102 reports one or more CSI-RS resource sets, one or more indexes may be based on the CSI-RS resource set IDs of multiple CSI-RS resource sets. For example, the mapping between one or more indexes and multiple CSI-RS resource sets may be based on the order of the CSI-RS resource IDs of the multiple CSI-RS resource sets (e.g., lowest ID priority or highest ID priority). In one (additional and / or alternative) example, one of the one or more indexes may be reserved for "no additional DM-RS". For example, index 0 of one or more indexes may be reserved for "no additional DM-RS". gNB 180 may (e.g., based on the reported indexes) determine the additional DM-RS pattern and may indicate the additional DM-RS pattern to WTRU 102.

[0224] WTRU 102 can determine WTRU capability reports for additional DM-RS. WTRU 102 can recommend additional DM-RS patterns, densities, and / or MCS. In one example, WTRU 102 can report WTRU capabilities for additional DM-RS to gNB 180. For example, WTRU 102 can transmit one or more RRC messages indicating one or more of the additional DM-RS pattern, additional DM-RS density, and / or one or more MCSs for additional DM-RS. For example, depending on the specific implementation of WTRU 102, WTRU 102 can report the additional DM-RS pattern and additional DM-RS density for receiving PDSCH. For example, WTRU 102 can report the MCS indicating the minimum MCS that may be required for PDSCH reception. WTRU 102 can report pairs of one or more of the MCS, additional DM-RS pattern, and / or additional DM-RS density. Each pair can indicate, for example, the minimum MCS of the reported additional DM-RS pattern and additional DM-RS density. gNB 180 can (e.g., based on WTRU capability reports) schedule PDSCH and / or PUSCH with additional DM-RS.

[0225] WTRU 102 may determine additional DM-RS, for example, based on SRS. Additional DM-RS (e.g., in addition to PDSCH DM-RS and / or PUSCH DM-RS) may be supported. Additional DM-RS may, for example, reside in an SCS without DM-RS ports for PDSCH and / or PUSCH to provide enhanced channel estimation performance in the frequency domain. In one example, additional DM-RS based on AP CSI-RS may be supported. For example, explicit AP CSI-RS triggering or implicit AP CSI-RS triggering (e.g., via a CSI request field) may be supported via UL DCI (e.g., in DCI format 0_0, DCI format 0_1, or DCI format 0_2) and / or DLDCI (e.g., in DCI format 1_0, DCI format 1_1, or DCI format 1_2). WTRU 102 may receive a scheduled PDSCH from gNB 180 and indicate the DCI for AP CSI-RS triggering for additional DM-RS. The WTRU 102 can (e.g., based on DCI) receive and decode PDSCH with an additional DM-RS.

[0226] WTRU 102 may determine the additional DM-RS configuration, for example, based on SRS. For example, WTRU 102 may receive an RRC message that includes multiple SRS resource sets. WTRU 102 may (e.g., based on multiple SRS resource sets) receive an RRC message that includes a set of multiple SRS resource sets for the additional DM-RS configuration. For example, WTRU 102 may receive an RRC message indicating the use of the additional DM-RS in that set of multiple SRS resource sets, such as... Figure 17 As shown. In one (e.g., additional and / or alternative) example, WTRU 102 may receive RRC messages for additional DM-RS in one or more SRS resource sets that include multiple SRS resource sets. WTRU 102 may (e.g., based on RRC messages including additional DM-RS) receive explicit and / or implicit signaling, such as to trigger additional DM-RS to receive PDSCH or transmit PUSCH. This configuration may have many different names. Other names for additional DM-RS may include, for example, supplementary DM-RS, frequency tracking RS, CSI-RS based DM-RS, etc.

[0227] Figure 17 An exemplary configuration for an additional DM-RS based on an SRS resource set is shown.

[0228] In the example, additional DM-RS configurations based on one or more SRS resource sets may be used, supported, or permitted, for example, with at least one of the following limitations: subcarrier spacing, operating frequency band, usage, WTRU capability, number of antenna ports for SRS, and / or modulation order for associated channels.

[0229] In the example where subcarrier spacing is a constraint, for example, if the subcarrier spacing of a channel (e.g., a DL / UL physical channel) is greater than a threshold (e.g., XkHz), an additional DM-RS can be configured, used, or supported, where the threshold can be predefined or configured.

[0230] In the example where the operating frequency band is used as a limitation, for example, when the operating frequency band is above a threshold (e.g., Y GHz), an additional DM-RS can be configured, used, and / or supported, where the threshold can be predefined or configured.

[0231] In examples where usage is used as a limitation, for example, if the first use (e.g., additional DM-RS) is used, additional DM-RS can be configured, used, and / or supported (e.g., otherwise, additional DM-RS may not be supported and / or used).

[0232] In the example where WTRU capability is used as a limitation, WTRU 102 can indicate whether it supports additional DM-RS.

[0233] In an example where the number of antenna ports used for SRS is a limitation, for example, if the number of antenna ports of the SRS resource is greater than a threshold (e.g., 4), the SRS resource can be used as an additional DM-RS, where the threshold can be predefined or configured.

[0234] In an example where the modulation order used for the associated channel is a constraint, for example, if the modulation order used for the channel (e.g., PUSCH) is higher than a threshold, additional DM-RS can be used or supported.

[0235] Figure 18 Example 1800 with an additional DM-RS for PUSCH is shown.

[0236] WTRU 102 can, for example, determine the additional DM-RS 1802 based on AP SRS.

[0237] WTRU 102 may determine the additional DM-RS 1802, for example, based on the SRS trigger in DCI 1804. For example, WTRU 102 may (e.g., based on multiple SRS resource sets) receive an RRC message including multiple SRS resource sets for the additional DM-RS 1802. WTRU 102 may receive an RRC message including a set of multiple SRS resource sets for an AP SRS request field. WTRU 102 may (e.g., based on the set of SRS resource sets) receive a DCI 1804 that schedules PDSCH / PUSCH and triggers one or more SRS resource sets in that set. WTRU 102 may (e.g., for a DCI that schedules PDSCH) receive and decode a PDSCH with the additional DM-RS 1802 based on the AP SRS. WTRU 102 may (e.g., for a DCI that schedules PUSCH) transmit a PUSCH with the additional DM-RS 1802 based on DCI 1804.

[0238] Figure 19 Example 1900 has an additional DM-RS with SP SRS for PDSCH decoding.

[0239] WTRU 102 may determine the additional DM-RS 1902, for example, based on SP SRS. WTRU 102 may determine the additional DM-RS 1902, for example, based on SP SRS activation / deactivation 1906. For example, it may be determined based on a combination of SP SRS activation 1906, the scheduled MCS and / or DCI of data (e.g., PDSCH or PUSCH).

[0240] For example, WTRU 102 may receive an RRC message including multiple SRS resource sets for attaching DM-RS 1902. One set of SRS resource sets among the multiple SRS resource sets may include the SRS resource sets for attaching DM-RS 1902. WTRU 102 may (e.g., based on the set of SRS resource sets) receive MAC CE messages to activate / deactivate the set of SRS resource sets. WTRU 102 may receive DCI 1904 for scheduling PDSCH or PUSCH. WTRU 102 may (e.g., based on the activation of the set) determine whether one or more SRS resource sets in the set are available for attaching DM-RS 1902. For example, if one or more SRS resource sets are activated in a slot scheduled for PDSCH, WTRU 102 may use one or more SRS resource sets for attaching DM-RS 1902. The MCS of the scheduled PDSCH or PUSCH may be considered (e.g., in addition to activation). In one example, for instance, when one or more SRS resource sets of the group are activated and the MCS of the scheduled PDSCH or PUSCH is above a threshold, WTRU 102 may use one or more SRS resource sets for additional DM-RS 1902. Explicit signaling (e.g., in addition to activation) indicating the allocation of additional DM-RS 1902 may be used. In one example, for instance, if one or more SRS resource sets of the group are activated and DCI1904 indicates the use of one or more SRS resource sets as additional DM-RS 1902, then WTRU 102 may use one or more SRS resource sets as additional DM-RS 1902.

[0241] WTRU 102 may determine additional DM-RS, for example, based on dynamic signaling. Additional DM-RS may be supported (e.g., in addition to PDSCH DM-RS and / or PUSCH DM-RS). One or more dynamic signals may indicate a set of RSs in one or more scheduled time slots as additional DM-RS. In one example, one or more dynamic signals may be based on DCI. For example, WTRU 102 may receive a DCI indicating whether the set of RSs is used as an additional DM-RS. In one (additionally and / or alternatively) example, one or more dynamic signals may be based on MAC CE. For example, WTRU 102 may receive one or more MAC CE messages indicating whether the set of RSs is activated or deactivated as an additional DM-RS.

[0242] WTRU 102 may determine additional DM-RS configuration, for example, based on dynamic signaling. In one example, a dynamic indication may determine the functionality of a reference signal located in a time slot. For example, the reference signal may be configured and transmitted in a time slot in a periodic, aperiodic, or semi-persistent (SP) manner. WTRU 102 may be instructed (e.g., via DCI and / or MAC CE) how to use the reference signal located in the time slot. For example, the functionality of a reference signal located in or transmitted in a time slot may be determined by a dynamic indication in a DCI and / or one or more MAC CE messages. This indication may determine the functionality of the reference signal, which may include, for example, at least one of time / frequency tracking, synchronization, phase noise tracking, CSI measurement, demodulation, detection, and localization.

[0243] A DCI that indicates the function of a reference signal located in the same time slot #n can be monitored or received in time slot #n. A DCI can be received or monitored in a time slot (e.g., time slot #nx, where x can be a non-negative integer) to schedule associated PDSCH transmissions in time slot #n.

[0244] One or more MAC CE messages that can indicate the activation / deactivation of a function of a reference signal located in or after time slot #n can be received or monitored in a time slot (e.g., time slot #nx, where x can be a non-negative integer).

[0245] The function set of the reference signal can be pre-configured. One or more configured functions can be indicated in the associated DCI or MAC CE. In one (e.g., additional or alternative) example, two types of functions (e.g., measurement and / or demodulation) can be used.

[0246] The dynamic determination of the function of the reference signal may (e.g., only) be used for a specific type of reference signal (e.g., CSI-RS and / or SRS).

[0247] Figure 20 Example 2000 with an additional DM-RS featuring DCI is shown.

[0248] WTRU 102 may, for example, be based on DCI 2004 to determine additional DM-RS 2002.

[0249] WTRU 102 may determine the additional DM-RS 2002, for example, based on a DCI indication (e.g., associating all RSs in the scheduled time slot with the DM-RS). Dynamic signaling may be used to support an indication that a group of RSs or all RSs in the scheduled time slot (e.g., CSI-RS2006 and / or TRS 2008) are used as additional DM-RS 2002. In one example, WTRU 102 may receive a DCI 2004 that (i) indicates that a group of RSs or all RSs in the scheduled time slot are used as additional DM-RS 2002 and / or (ii) schedules PDSCH / PUSCH. For example, a value of 0 may indicate that no RSs in the scheduled time slot are used for additional DM-RS 2002, while a value of 1 may indicate that a group of RSs or all RSs in the scheduled time slot are used for additional DM-RS 2002. Figure 20 An exemplary operation is shown based on whether the RS group or all RSs in the time slot scheduled by the DCI 2004 are used for the additional DM-RS 2002. Figure 20 As shown, WTRU 102 can (e.g., before receiving an indication) receive all RSs for its own functions. For example, WTRU can measure TRS 2008 in a normal time slot to achieve fine time / frequency synchronization. In one (e.g., additional or alternative) example, WTRU can measure CSI-RS 2006 in a normal time slot to measure CSI. For example, if WTRU 102 receives a DCI 2004 indicating that a set of RSs or all RSs in a scheduled time slot are used for additional DM-RS 2002, then WTRU 102 can use TRS 2008 and CSI-RS 2006 in the scheduled time slot as additional DM-RS 2002.

[0250] WTRU 102 may determine whether to ignore a configured RS, for example, based on a group DCI indication. WTRU 102 may receive an indication (e.g., in the DCI) that the RS group and / or all RSs in the scheduled time slot are used for the additional DM-RS 2002. The indication may be provided to other WTRUs using the RS group or all RSs in the scheduled time slot. For example, TRS 2008 may be a cell-specific RS for time / frequency synchronization. WTRUs 102a-d (e.g., all WTRUs) in the same cell may share a TRS. CSI-RS 2006 may be a cell-specific RS, for example, for measuring non-precoded channels. Other WTRUs may (e.g., in response to the indication) measure RSs with different analog beams and / or radio channels, and may assume that the RSs are in the same analog beam and / or radio channel. This assumption may lead to significant errors in time / frequency synchronization. CSI-RS 2006 with different analog beams and / or radio channels (e.g., similar to TRS 2008) can lead to significant errors in CSI measurement and CSI processing. These errors can be prevented, for example, by indicating that RSs are not measured (e.g., from gNB 180). For example, a WTRU (e.g., different from the WTRU receiving the scheduled DCI) may receive a set of RSs in the scheduled time slot and / or an indication that all RSs are not used for measurement. For example, the WTRU may not measure or may ignore TRS 2008 in the time slot for time / frequency synchronization. For example, the WTRU may not measure or may ignore CSI-RS 2006 in the time slot for CSI measurement. The DCI to the WTRU can be a group DCI. Multiple WTRUs can receive information simultaneously, for example, by using a group DCI.

[0251] Figure 21 Example 2100 with an additional DM-RS featuring a MAC CE is shown.

[0252] WTRU 102 may determine the additional DM-RS 2102, for example, based on MAC CE. WTRU 102 may determine the additional DM-RS 2102, for example, based on MAC CE activation / deactivation 2104a / 2104b. In one example, WTRU 102 may receive activation / deactivation MAC CE 2104a / 2104b, which may indicate that a set of RSs or all RSs in one or more scheduled time slots are used as additional DM-RS 2002. Figure 21 An exemplary operation is shown, based on an instruction to use a set of RSs or all RSs in one or more scheduled time slots as an activation / deactivation MAC CE 2104a / 2104b for an additional DM-RS 2102. For example... Figure 21As shown, WTRU 102 may (e.g., before receiving a MAC CE indicating activation of the additional DM-RS) receive a group of RSs and / or all RSs (e.g., CSI-RS 2106 and / or TRS 2108) for its own functions. For example, WTRU 102 may measure TRS 2108 in a normal time slot to achieve fine time / frequency synchronization. In one (e.g., additional or alternative) example, WTRU 102 may measure CSI-RS 2106 in a normal time slot to measure CSI. For example, if WTRU 102 receives an activation MAC CE 2104a indicating that a group of RSs or all RSs in the scheduled time slot are used for additional DM-RS 2102, WTRU 102 may use TRS 2108 and CSI-RS 2106 in the scheduled time slot as additional DM-RS 2102 (e.g., until WTRU 102 receives a deactivation MAC CE 2104b from gNB 180). WTRU 102 may (e.g., when WTRU 102 does not receive a PDSCH from gNB 180) not measure the RS group and / or all RSs, for example, to allow other WTRUs to use the RS group and / or all RSs for the attached DM-RS 2102. WTRU 102 may (e.g., after receiving the deactivation MAC CE 2104b) again receive the RS group and / or all RSs for its own functions.

[0253] The WTRU 102 can determine the measurement based on the RS type.

[0254] WTRU 102 can make one or more determinations based on RS type. For example, WTRU 102 can determine the additional DM-RS 2102 based on RS type. WTRU 102 can receive dynamic signaling (e.g., DCI and / or MAC CE) that indicates a set of RSs and / or all RSs in one or more time slots are used as additional DM-RS 2102. This indication can be based on the RS type. For example, the RS type can be configured based on RS resources, RS resource sets, etc. In one example, the RS type can be configured (e.g., flexible or fixed).

[0255] For example, if the RS type indication of an RS is fixed, the RS can be used for its own functions (e.g., regardless of the indication). For example, if a TRS (e.g., 2008, 2108) indicates that the RS type is fixed, then the TRS (e.g., 2008, 2108) can be used for fine time / frequency tracking (e.g., regardless of dynamic signaling). For example, if the RS type is flexible, the RS can be used to attach DM-RS 2102. For example, if a TRS (e.g., 2008, 2108) indicates that it is flexible as the RS type, then the TRS can be used to attach DM-RS 2102 based on dynamic signaling.

[0256] WTRUs can determine RS measurements based on RS type. One or more WTRUs can receive dynamic signaling (e.g., DCI or MAC CE) that does not measure a set of RSs and / or all RSs in one or more time slots. This indication can be based on the RS type. In one example, the RS type can be configured (e.g., flexible or fixed).

[0257] For example, if the RS type indication of an RS is fixed, the RS may not be measured for its own function (e.g., unrelated to dynamic signaling). For example, if a TRS (e.g., 2008, 2108) indicates the RS type as fixed, then the TRS (e.g., 2008, 2108) can be measured (e.g., unrelated to dynamic signaling). For example, if the RS type is flexible, the RS may not be used for its own function. For example, if a TRS (e.g., 2008, 2108) indicates the RS type as flexible, then based on dynamic signaling, the TRS (e.g., 2008, 2108) may not be used for fine time / frequency tracking.

[0258] WTRU 102 can identify higher density DM-RS. The density of RS in the frequency domain is inversely proportional to the increase of SCS. Low RS density can reduce channel estimation performance in the frequency domain. Higher density DM-RS can be supported, for example, by gNB 180 and / or one or more of the following solutions supported by WTRU: (i) higher density DM-RS with Type 1 and Type 2 DM-RS having REs for other DM-RS ports, (ii) higher density DM-RS with symbols different from the DM-RS (e.g., adjacent or non-adjacent), (iii) frequency hopping of additional DM-RS, (iv) DM-RS port aggregation, and / or (v) PT-RS enhancement for improving channel estimation performance in the frequency domain.

[0259] WTRU 102 can determine the configuration and / or triggering of higher density DM-RS.

[0260] WTRU 102 can make determinations based on RRCs. In one example, the configuration of the higher-density DM-RS can be based on one or more RRC messages. For example, WTRU 102 can receive one or more RRC messages indicating, for example, the configuration of the higher-density DM-RS for PDSCH and / or PUSCH. WTRU 102 can (e.g., based on configuration) receive higher-density DM-RS for receiving PDSCH and / or transmitting PUSCH.

[0261] WTRU 102 can determine the use of higher-density DM-RS based on the MCS in the RRC configuration. In one example, the configuration of higher-density DM-RS can be based on the MCS. For example, WTRU 102 can receive one or more RRC messages indicating the configuration of higher-density DM-RS for PDSCH and / or PUSCH. WTRU 102 can (e.g., based on configuration) receive one or more RRC messages indicating one or more MCS as a threshold for higher-density DM-RS. WTRU 102 can (e.g., based on one or more MCS) determine whether to use higher-density DM-RS. For example, if the scheduled MCS is below or above one or more thresholds, WTRU 102 can determine (e.g., when WTRU 102 receives the DCI for scheduling PDSCH and / or PUSCH) to use higher-density DM-RS.

[0262] WTRU 102 can make determinations based on frequency bands. In one example, the configuration of higher-density DM-RS can be based on frequency bands. For example, WTRU 102 can (e.g., when WTRU 102 receives a DCI scheduling PDSCH and / or PUSCH) determine whether to use higher-density DM-RS based on the scheduled frequency band. For example, if WTRU 102 receives a cross-scheduling DCI in FR1 to schedule PDSCH / PUSCH transmissions above 52.6 GHz, then WTRU 102 can (e.g., based on higher-density DM-RS) receive on the PDSCH or transmit on the PUSCH. For example, if WTRU 102 receives a scheduling DCI above 52.6 GHz to schedule PDSCH / PUSCH transmissions above 52.6 GHz, then WTRU 102 can (e.g., based on higher-density DM-RS) receive on the PDSCH or transmit on the PUSCH.

[0263] WTRU 102 can make determinations based on system bandwidth and / or bandwidth portion (BWP) size. In one example, the configuration of higher-density DM-RS can be based on system bandwidth and / or bandwidth portion (BWP) size. For example, if WTRU 102 receives a DCI scheduling PDSCH and / or PUSCH, WTRU 102 can (e.g., based on system bandwidth and / or BWP size) determine whether to use higher-density DM-RS. For example, if WTRU 102 receives a cross-scheduling DCI in FR1 to schedule PDSCH / PUSCH transmissions within the system bandwidth or a BWP size greater than a specific bandwidth, WTRU 102 can (e.g., based on higher-density DM-RS) receive PDSCH or transmit PUSCH. In one example, WTRU 102 can receive one or more RRC messages indicating a specific bandwidth. In one (e.g., alternative or additional) example, WTRU 102 can report a specific bandwidth via WTRU capabilities. In one (e.g., alternative or additional) example, a specific bandwidth can be predetermined.

[0264] WTRU 102 can make determinations based on SCS. In one example, the configuration of higher-density DM-RS can be based on SCS. For example, if WTRU 102 receives a DCI scheduling PDSCH and / or PUSCH, WTRU 102 can determine whether to use higher-density DM-RS based on the scheduled SCS. For example, if WTRU 102 receives a DCI scheduling PDSCH / PUSCH with an SCS higher than an SCS threshold (e.g., 480 kHz or 960 kHz), WTRU 102 can receive PDSCH or transmit PUSCH based on higher-density DM-RS. In one example, WTRU 102 can receive one or more RRC messages indicating the SCS threshold. In one (e.g., alternative or additional) example, WTRU 102 can report the SCS threshold via WTRU capabilities. In one (e.g., alternative or additional) example, the SCS threshold can be predetermined.

[0265] The WTRU 102 can be determined based on DCI. In one example, the configuration of a higher density DM-RS can be based on DCI.

[0266] WTRU 102 can make this determination based on explicit indication fields in the DCI. For example, if WTRU 102 receives a DCI indicating PDSCH reception with higher density DM-RS and / or PUSCH transmission with higher density DM-RS, WTRU 102 can determine whether to use higher density DM-RS. For example, if the DCI field for higher density DM-RS indicates 0, WTRU 102 can receive PDSCH or transmit PUSCH without higher density DM-RS. For example, when the DCI field for higher density DM-RS indicates 1, WTRU 102 can receive and / or transmit PUSCH with higher density DM-RS.

[0267] WTRU 102 can make a determination based on the priority indication field in the DCI. In one example, the configuration of higher density DM-RS can be based on the priority indication field in the DCI. For example, WTRU 102 can receive a DCI with a priority indication for scheduling PDSCH / PUSCH. For example, WTRU 102 can determine whether to use higher density DM-RS based on the priority indication. For example, if WTRU 102 receives a priority indication below a certain number (e.g., a threshold), WTRU 102 can receive PDSCH and / or transmit PUSCH with higher density DM-RS. For example, if WTRU 102 receives a priority indication above a certain number (e.g., a threshold), WTRU 102 can receive PDSCH and / or transmit PUSCH without higher density DM-RS. In one example, WTRU 102 can receive one or more RRC messages indicating a certain number of priority indications. In one (e.g., alternative or additional) example, WTRU 102 can report a certain number of priority indications via WTRU capabilities. In one (e.g., alternative or additional) example, a specific number of priority indicators may be predetermined.

[0268] The determination of WTRU 102 may be based on the antenna port field in the DCI. In one example, the configuration of higher-density DM-RS may be based on the antenna port field in the DCI. For example, WTRU 102 may receive DCIs that schedule PDSCH and / or PUSCH transmissions with higher-density DM-RS, for example, based on the defined antenna port field. The antenna port field may be based on a table defined for higher-density DM-RS (e.g., type 3DM-RS) and / or a DM-RS antenna port indication table.

[0269] Figure 22 Example 2200 of a defined antenna port indication table for higher density DM-RS is shown.

[0270] The determination of WTRU 102 can be based on the antenna port field defined in the DCI. Figure 22 An example of a defined antenna port indication table for higher density DM-RS is shown. Figure 22 As shown, tables can be defined for higher-density DM-RS. WTRU 102 can receive one or more RRC messages indicating the defined tables for higher-density DM-RS. WTRU 102 can (e.g., based on the defined tables) receive PDSCH and / or PUSCH schedules for higher-density (e.g., 2) DMRS.

[0271] Figure 23 Example 2300 is an antenna port indicator table for normal density and higher density DM-RS based on the antenna port indicator table.

[0272] The determination of WTRU 102 can be based on the extended antenna port field in DCI. Figure 23 This is a table illustrating an example of a second set of antenna ports based on the first set of antenna ports. The antenna port table for higher density DM-RS may include reserved values ​​from the antenna port table for single-symbol type 1 DM-RS for DM-RS used in higher density DM-RS. For example... Figure 23 As shown, reserved values ​​12 to 14 can be used as DM-RS ports 0 and / or 1 with higher density DM-RS (e.g., 2).

[0273] The determination of WTRU 102 can be based on a combination of configuration methods. The configuration of higher density DM-RS can also be based on a combination of configuration methods (e.g., as described herein).

[0274] The determination of WTRU 102 can be based on RRC and DCI. In one example, the configuration can be based on RRC messages and DCI indications. For example, WTRU 102 can receive one or more RRC messages indicating the configuration for higher-density DM-RS for PDSCH and / or PUSCH. WTRU 102 can (e.g., based on configuration) receive, for example based on the antenna port field, a DCI indicating PDSCH reception with higher-density DM-RS or PUSCH transmission with higher-density DM-RS. WTRU 102 can (e.g., based on configuration and indications) receive PDSCH with higher-density DM-RS and / or transmit PUSCH with higher-density DM-RS.

[0275] The determination of WTRU 102 can be based on SCS and DCI. In one example, the configuration can be based on SCS and DCI indications. For example, WTRU 102 can receive DCIs of PDSCH / PUSCHs scheduled with an SCS higher than an SCS threshold (e.g., 480 kHz or 960 kHz). The DCI can indicate whether to use higher density DM-RS to receive PDSCHs and / or transmit PUSCHs. WTRU 102 can (e.g., based on SCS and indications) receive PDSCHs with higher density DM-RSs and / or transmit PUSCHs with higher density DM-RSs.

[0276] WTRU 102 can identify higher density DM-RS for (e.g., single-symbol) type 1DM-RS.

[0277] WTRU 102 determines the RE for a single-symbol type 1 DM-RS. REs for other DM-RS ports in the DM-RS can be used for the scheduled DM-RS port, for example, to support higher-density DM-RS. In one example, REs for other DM-RS ports can be used for the scheduled DM-RS port, for example, to achieve better channel estimation performance in the frequency domain. Figure 24 An example of a higher-density DM-RS with a type 1 single-symbol DM-RS is shown. For example... Figure 24 As shown, the REs for DM-RS ports #2 and #3 can be used for DM-RS ports #0 and #1. The port numbers for higher-density DM-RS used in this example (e.g., DM-RS ports #0 and #1) may have different numbers (e.g., DM-RS ports #4 and #5).

[0278] Figure 24 Example 2400 with a higher DM-RS density of single-symbol type 1DM-RS is shown.

[0279] WTRU 102 can identify code division multiplexing (CDM) for single-symbol type 1DM-RS. For example... Figure 24 As shown in Example 2400, multiple (e.g., two) CDM mappings (e.g., pattern #1 and pattern #2) for higher DM-RS densities of single-symbol type 1DM-RS can be provided. Pattern #1 can support CDM between consecutive REs in the frequency domain (e.g., as well as single-symbol type 1DM-RS). For example, pattern #1 can be more easily implemented if it assigns codes with adjacent REs and / or does not require the use of memory. For example, pattern #1 may not support coexistence between single-symbol type 1DM-RS ports and single-symbol higher density DM-RS ports because the CDM sequences of single-symbol type 1DM-RS ports and single-symbol higher density DM-RS ports may not be orthogonal.

[0280] Pattern #1 supports CDM with continuous REs. Pattern #2 supports CDM based on a comb (e.g., a comb pattern) with one RE interval. Pattern #1 may not support orthogonal multiplexing between a single-symbol type 1 DM-RS port and a single-symbol high-density DM-RS port. Pattern #2 supports orthogonal multiplexing between DM-RS ports and single-symbol high-density DM-RS ports.

[0281] WTRU 102 can determine the sequence mapping for single-symbol type 1DM-RS. Figure 25 An exemplary sequence mapping for single-symbol type 1DM-RS is shown. For example... Figure 25 As shown in the example, multiple (e.g., two) sequence maps 2500 (e.g., sequence map #1 and sequence map #2) can be provided for higher DM-RS densities of single-symbol type 1 DM-RS. Sequence map #1 can map sequences sequentially. Sequence map #1 is easier to implement and may not require the use of memory. For example, if the pseudo-random (PN) sequence map is not designed for low correlation, sequence map #1 can provide higher correlation between single-symbol type 1 DM-RS ports and single-symbol higher density DM-RS.

[0282] Sequence mapping #1 supports sequential sequence mapping. Sequence mapping #2 can, for example, assign the same sequence to every two REs in the frequency domain. For example, interference between sequences at the DM-RS port may be lower (e.g., for sequence mapping #2) due to low correlation.

[0283] Figure 25 Example 2500 of a DM-RS sequence mapping with a single symbol type 1DM-RS is shown.

[0284] WTRU 102 can determine higher-density DM-RS for dual-symbol type 1DM-RS. WTRU 102 can determine REs for dual-symbol type 1DM-RS. REs for other DM-RS ports (e.g., for dual-symbol type 1DM-RS) can be used for the scheduled DM-RS ports to achieve, for example, better channel estimation performance in the frequency domain (e.g., and for single-symbol type 1DM-RS). Figure 26 and Figure 27 An example of a higher-density DM-RS with a single-symbol type 1DM-RS is shown. For example... Figure 26 and Figure 27 As shown in Examples 2600 and 2700, the REs for DM-RS ports #4, #5, #6, and #7 can be used for DM-RS ports #0, #1, #2, and #3. The port numbers for higher-density DM-RS used in the examples of this disclosure (e.g., DM-RS ports #0, #1, #2, and #3) may have different numbers (e.g., DM-RS ports #8, #9, #10, and #11).

[0285] Figure 26 Example 2600 of pattern #1 with higher DM-RS density and dual-symbol type 1DM-RS is shown.

[0286] Figure 27 Example 2700 of pattern #2 with higher DM-RS density and dual-symbol type 1DM-RS is shown.

[0287] WTRU 102 can determine the CDM of a dual-symbol type 1DM-RS. For example... Figure 26 and Figure 27 As shown in the example, multiple (e.g., two) CDM mappings (e.g., ...) can be provided for higher DM-RS densities of dual-symbol type 1DM-RS. Figure 26 Pattern #1 and Figure 27 Pattern #2 in the diagram. Pattern #1 can support CDM between consecutive REs in the frequency domain. For example, Pattern #1 is easier to implement if it sequentially assigns codes with adjacent REs and / or does not require the use of memory. For example, Pattern #1 may not support coexistence between dual-symbol type 1DM-RS and higher-density dual-symbol DM-RS if the CDM sequences are not orthogonal.

[0288] Pattern #1 supports CDMs with continuous REs in the frequency domain. Pattern #2 supports CDMs based on combs (e.g., comb patterns) with one RE interval in the frequency domain. Pattern #1 may not support orthogonal multiplexing between dual-symbol type 1 DM-RS and dual-symbol high-density DM-RS. Pattern #2 supports orthogonal multiplexing between dual-symbol type 1 DM-RS and high-density dual-symbol DM-RS.

[0289] WTRU 102 can determine the sequence mapping for dual-symbol type 1DM-RS. Figure 28 Example 2800 is shown for sequence mapping of dual-symbol type 1DM-RS. For example... Figure 28 As shown in Example 2800, multiple (e.g., two) sequence mappings (e.g., sequence mapping #1 and sequence mapping #2) can be provided for higher DM-RS densities of dual-symbol type 1 DM-RS. Sequence mapping #1 can map sequences sequentially. For example, the sequence mapping can be more easily implemented if sequence mapping #1 sequentially allocates codes and / or does not use memory. For example, if the PN sequence mapping is not designed for low correlation, sequence mapping #1 can provide higher correlation between dual-symbol type 1 DM-RS and higher density dual-symbol DM-RS.

[0290] Sequence mapping #1 can support sequential sequence mapping. Sequence mapping #2 can, for example, assign the same sequence to every two REs in the frequency domain. For example, interference between sequences at the DM-RS port (e.g., for sequence mapping #2) may be lower (due to low correlation).

[0291] Figure 28 Example 2800 of a DM-RS sequence mapping with dual symbol type 1DM-RS is shown.

[0292] WTRU 102 can identify higher density DM-RS for type 2 DM-RS.

[0293] WTRU 102 can determine higher-density DM-RSs for single-symbol type 2DM-RSs. WTRU 102 can determine REs for higher-density single-symbol type 2DM-RSs. REs for other types of 2DM-RS ports in the DM-RS (e.g., and type 1DM-RS) can be used, for example, the scheduled DM-RS ports to support higher-density DM-RSs. In one example, REs for other DM-RS ports can be used for the scheduled DM-RS ports to achieve better channel estimation performance in the frequency domain. Figure 29 Example 2900 of a higher-density DM-RS with type 2 single-symbol DM-RS is shown. (e.g.) Figure 29 As shown in Example 2900, REs for DM-RS ports #2, #3, #4, and #5 can be used for DM-RS ports #0 and #1. The port numbers for higher-density DM-RS used in the examples herein (e.g., DM-RS ports #0 and #1) may have different numbers (e.g., DM-RS ports #6 and #7).

[0294] Figure 29 Example 2900 with a higher DM-RS density and a single-symbol type 2DM-RS is shown.

[0295] WTRU 102 can identify code division multiplexing (CDM) for single-symbol type 2DM-RS. For example... Figure 29 As shown in Example 2900, the CDM mapping can be based on a single-symbol type 2DM-RS. The CDM mapping can be supported by, for example, by assigning codes with adjacent REs, and can enable orthogonal multiplexing between DM-RS ports and single-symbol high-density DM-RS ports.

[0296] WTRU 102 can determine sequence mapping for single-symbol type 2DM-RS. Figure 30 Example 3000 is shown for sequence mapping of single-symbol type 2DM-RS. For example... Figure 30As shown in Example 3000, multiple (e.g., two) sequence maps (e.g., sequence map #1 and sequence map #2) can be provided for higher DM-RS densities of single-symbol type 2DM-RS. Sequence map #1 can map sequences sequentially. Sequence map #1 is easier to implement and may not require the use of memory. For example, if the PN sequence map is not designed for low correlation, sequence map #1 can provide higher correlation between single-symbol type 2DM-RS and higher-density dual-symbol DM-RS.

[0297] Sequence mapping #1 supports sequential sequence mapping. Sequence mapping #2 can, for example, assign the same sequence to every two REs during the six REs in the frequency domain. For example, interference between sequences at the DM-RS port (e.g., for sequence #2 mapping) may be lower due to low correlation.

[0298] Figure 30 Example 3000 of a DM-RS sequence mapping with a single symbol type 2DM-RS is shown.

[0299] WTRU 102 can determine higher-density DM-RS for dual-symbol type 2DM-RS. WTRU 102 can determine REs for dual-symbol type 2DM-RS. REs for other DM-RS ports (e.g., for dual-symbol type 2DM-RS) can be used for the scheduled DM-RS ports to, for example, achieve better channel estimation performance in the frequency domain. Figure 31 An example 3100 of a higher-density DM-RS with dual-symbol type 2DM-RS is shown. For example... Figure 31 As shown in the examples, REs for DM-RS ports #2, #3, #4, #5, #8, #9, #10, and #11 can be used for DM-RS ports #0, #1, #2, and #3. The port numbers for higher-density DM-RS used in the examples in this paper (e.g., DM-RS ports #0, #1, #2, and #3) can have different numbers (e.g., DM-RS ports #12, #13, #14, and #15).

[0300] Figure 31 Example 3100 with a higher DM-RS density having a dual-symbol type 2DM-RS is shown.

[0301] WTRU 102 can identify code division multiplexing (CDM) for dual-symbol type 2DM-RS. For example... Figure 31 As shown in the example, CDM mapping can be based on dual-symbol type 2DM-RS. CDM mapping can be supported by specific implementations, for example, by assigning codes with adjacent REs, and can enable orthogonal multiplexing between DM-RS ports and single-symbol high-density DM-RS ports.

[0302] WTRU 102 can determine the sequence mapping for dual-symbol type 2DM-RS. Figure 32 An exemplary sequence mapping for single-symbol type 2DM-RS is shown. For example... Figure 32 As illustrated in the example, multiple (e.g., two) sequence maps (e.g., sequence map #1 and sequence map #2) can be provided for higher DM-RS densities of dual-symbol type 2DM-RS. Sequence map #1 can map sequences sequentially. Sequence map #1 is easier to implement and may not require the use of memory. For example, if the PN sequence map is not designed for low correlation, sequence map #1 can provide higher correlation between dual-symbol type 2DM-RS and higher density dual-symbol DM-RS.

[0303] Figure 32 Example 3200 of a DM-RS sequence mapping with dual symbol type 2DM-RS is shown.

[0304] WTRU 102 can determine the DM-RS type used for higher density DM-RS. Higher density DM-RS for type 1 and / or type 2 DM-RS can be defined as a subset of, for example, one or more DM-RS types (e.g., type 1 and / or type 2). In one (e.g., additional or alternative) example, one or more other DM-RS types (e.g., type 3 and / or type 4) can be defined to configure higher density DM-RS, for example, to provide enhanced channel estimation in the frequency domain.

[0305] WTRU 102 can determine DM-RS symbols for higher-density DM-RS. WTRU 102 can determine higher-density DM-RS REs using symbols different from those used for DM-RS ports. WTRU 102 can determine higher-density DM-RS REs using different symbols for Type 1 DM-RS. In one example, additional REs for higher-density DM-RS can be supported using OFDM symbols different from those used for DM-RS ports. For example, as the SCS increases (e.g., from 15 kHz to 960 kHz), the slot duration can be inversely proportional (e.g., from 1 ms to 0.156 ms). For example, due to the reduced slot duration, changes in the radio channel response in the time domain may not be significant in the time domain. A set of DM-RS REs for higher density can be transmitted using different symbols. Figure 33 and Figure 34 Examples 3300 and 3400 are shown for higher-density DM-RS transmission using type 1 DM-RS with different symbols. For example, as... Figure 33As illustrated in the example, WTRU 102 can transmit or receive higher-density DM-RS using adjacent symbols. For example, to receive a PDSCH, WTRU 102 can measure the channel impulse response of the higher-density DM-RS RE. WTRU 102 can estimate the channel impulse response of the PDSCH RE, for example, by jointly estimating the channel impulse responses using different symbols (e.g., by assuming that the channel impulse response does not change with symbols in the time domain). WTRU 102 can decode the PDSCH (e.g., based on the estimated channel impulse response). Figure 34 As shown in the example, higher density DM-RS transmission can be performed using non-adjacent symbols.

[0306] Figure 33 Example 3300 of a higher density DM-RS with a single-symbol type 1DM-RS employing adjacent symbols is shown.

[0307] Figure 34 Example 3400 of a higher density DM-RS with a single-symbol type 1DM-RS employing non-adjacent symbols is shown.

[0308] WTRU 102 can identify higher density DM-RS REs using different symbols for type 2 DM-RS. Type 2 DM-RS (e.g., and type 1 DM-RS) can support higher density DM-RS using adjacent or non-adjacent symbols. Figure 35 and Figure 36 Examples 3500 and 3600 are shown for higher-density DM-RS transmission using type 2DM-RS with different symbols.

[0309] Figure 35 Example 3500 of a higher density DM-RS with a single-symbol type 2DM-RS employing adjacent symbols is shown.

[0310] Figure 36 Example 3600 of a higher density DM-RS with a single-symbol type 2DM-RS employing non-adjacent symbols is shown.

[0311] Those skilled in the art will recognize that the same principle can be applied to dual-symbol type 1 DM-RS ports and dual-symbol type 2 DM-RS ports, for example, to provide higher density DM-RS using symbols different from other DM-RS symbols.

[0312] WTRU 102 can determine frequency hopping using additional DM-RS symbols.

[0313] In one example, one or more DM-RS ports with additional DM-RS symbols can support frequency hopping, for example, to achieve better channel estimation in the frequency domain.

[0314] In one (e.g., another or alternative) example, the RE location of the DM-RS port in an OFDM symbol can be determined, for example, based on the OFDM symbol index. In one example, the RE set can be used for the DM-RS port in an OFDM symbol, and the frequency location of the RE set can be determined based on the OFDM symbol index. For example, the RE set can be located on the even subcarriers of the first OFDM symbol index and the odd subcarriers of the second OFDM symbol index.

[0315] In one example, the first and second OFDM symbol indices can be determined, for instance, based on modulo operations of the OFDM symbol indices. The first OFDM symbol index can be an OFDM symbol index (m) such that m modulo 2 = 0, and the second OFDM symbol index can be an OFDM symbol index (m) such that m modulo 2 = 1. The first OFDM symbol index can be a first OFDM symbol containing a DM-RS port in a time slot, and the second OFDM symbol index can be a second OFDM symbol containing a DM-RS port in a time slot.

[0316] In one (e.g., another or alternative) example, the RE offset can be used to determine the RE position of the DM-RS port in the OFDM symbol. One or more of the following may apply.

[0317] The maximum RE_offset value can be based on, for example, the frequency interval configured by the DM-RS. For example, the frequency interval configured by the DM-RS can be X (e.g., 2), and the maximum RE_offset (max_RE_offset) can be X-1 (e.g., 1).

[0318] The candidate values ​​for RE_offset can be, for example, {0,1,…,max_RE_offset}, where max_RE_offset can be determined based on, for example, the frequency spacing of the DM-RS pattern used and / or higher-level configurations (e.g., RRC or MAC-CE).

[0319] The RE_offset value can be determined based on at least one of, for example, the OFDM symbol index and / or the order of OFDM symbols containing DM-RS or DM-RS ports (e.g., the first OFDM symbol containing DMRS, the second OFDM symbol containing DMRS, and / or the third OFDM symbol containing DMRS).

[0320] The RE_offset value can be determined differently, for example, based on whether a single-symbol DM-RS and / or dual-symbol DM-RS configuration is used. For instance, if a single-symbol DM-RS is used, the RE_offset value can be determined based on the OFDM symbol index and / or the order of the OFDM symbols containing the DM-RS. For instance, if a dual-symbol DM-RS is used, the RE_offset value can be determined based on the OFDM symbol pairs and the order of the OFDM symbols containing the DMRS. For instance, a first pair of OFDM symbols used in a dual-symbol DM-RS can be associated with a first RE_offset value, and a second pair of OFDM symbols used in a dual-symbol DM-RS can be associated with a second RE_offset value.

[0321] RE_offset can be referred to as, for example, frequency shift, frequency hopping, frequency offset, subcarrier offset, and / or V-shift.

[0322] In one (e.g., another or alternative) example, the use of DM-RSRE_offset based on the OFDM symbol position or index in the time slot may be determined, for example, based on one or more of the following: (i) operating frequency band (e.g., > frequency threshold), (ii) subcarrier spacing (e.g., > subcarrier spacing threshold), (iii) DM-RS configuration type (type 1 or type 2), (iv) waveform (e.g., OFDM, DFT-s-OFDM), (v) modulation order and / or coding rate (e.g., MCS > threshold), (vi) channel coding type (e.g., LDPC, Turbo, Polar code), (vii) WTRU mobility speed, (viii) higher layer configuration (e.g., RRC or MAC-CE) and / or (ix) dynamic indication (e.g., DCI).

[0323] RE_offset, frequency shift, frequency hopping, frequency offset, subcarrier shift, subcarrier offset, and v-shift are used interchangeably in this article.

[0324] WTRU 102 can determine frequency hopping in type 1DM-RS. Figure 37 and Figure 38 Examples of frequency hopping with additional DM-RS symbols of single-symbol type 1DM-RS and single-symbol type 2DM-RS are shown in 3700 and 3800, respectively. Figure 37As shown in Example 3700, two additional DM-RS symbols can be configured for the WTRU. For example, if frequency hopping 3702 is not applied to the additional DM-RS 604, the WTRU 102 can (e.g., only) receive the pre-DM-RS 602 and the additional DM-RS 604 at the same frequency location. For example, if frequency hopping 3702 is applied to the additional DM-RS 604, the WTRU 102 can receive one of the additional DM-RS 604 at different frequency locations. For example, by assuming the time-domain channel remains unchanged, the WTRU 102 can use frequency hopping 3702 to jointly estimate the frequency-domain channel with the additional DM-RS 604.

[0325] WTRU 102 can determine the frequency hopping 3702 in type 2DM-RS. A single-symbol type 2DM-RS 604 with two additional DM-RS symbols can apply two frequency hopping 3702s in the frequency domain (e.g., the opposite of one frequency hopping 3702 in an additional DM-RS 604 of single-symbol type 1DM-RS). Figure 38 As shown in Example 3800, additional DM-RS symbols can be transmitted (e.g., each) at different frequency locations. WTRU 102 can (e.g., by assuming the time-domain channel remains unchanged) jointly estimate the frequency-domain channel with additional DM-RS 604 using frequency hopping 3702. Frequency hopping 3702 with additional DM-RS symbols can be applied to dual-symbol type 1 DM-RS ports and dual-symbol type 2 DM-RS ports, for example, to provide higher density DM-RS.

[0326] Figure 37 Example 3700 is a frequency hopping frequency cascaded DM-RS with a single-symbol type 1DM-RS.

[0327] Figure 38 Example 3800 is a frequency hopping example with an additional DM-RS of single-symbol type 2DM-RS.

[0328] WTRU 102 can determine DM-RS port aggregation. In one example, two or more DM-RS ports can be aggregated to provide enhanced channel estimation of DM-RS in the frequency domain. For example, DM-RS ports at different frequency locations or in different CDM groups can be aggregated to achieve enhanced channel estimation in the frequency domain. Figure 39 Example 3900 of DM-RS port aggregation based on single-symbol type 1DM-RS is shown. For example... Figure 39 As shown in Example 3900, DM-RS ports #0 and #2 in different frequency locations or different CDM groups can be aggregated. WTRU 102 can receive configuration and / or instructions for DM-RS port aggregation from gNB 180.

[0329] The aggregated DM-RS ports can be used to demodulate the same layer. For example, WTRU 102 may assume that the aggregated DM-RS ports are associated with the same PDSCH layer in the DL. WTRU 102 may (e.g., for UL) use the same pre-encoder for the aggregated DM-RS ports.

[0330] WTRU 102 can determine DM-RS port aggregation based on RRC messages. For example, WTRU 102 can receive one or more RRC messages indicating the aggregation of DM-RS ports. The indication may include one or more DM-RS ports to be aggregated. WTRU 102 can measure one or more DM-RS ports (e.g., based on the indication). WTRU 102 can jointly estimate the radio channel based on the measurement. WTRU 102 can decode the PDSCH, for example, based on the joint estimation.

[0331] WTRU 102 can determine DM-RS port aggregation based on DCI. For example, WTRU 102 can receive a DCI indicating the aggregation of DM-RS ports. The indication can be explicit or implicit. In an example of explicit indication, WTRU 102 can receive an explicit indication to aggregate DM-RS ports. For example, the DCI can explicitly indicate one or more indices of the DM-RS ports to be aggregated. WTRU 102 can (e.g., based on DCI) measure one or more DM-RS ports and jointly estimate the radio channel based on the measurements. WTRU 102 can (e.g., based on joint estimation) decode PDSCH. In an example of implicit indication, WTRU 102 can receive an implicit indication to aggregate DM-RS ports. In one example, scheduling PDSCH / PUSCH above a certain rank can indicate DM-RS port aggregation. For example, WTRU 102 can receive a DCI scheduling PDSCH / PUSCH with rank 2. DM-RS ports used for rank 2 can be aggregated for PDSCH reception. Scheduling a DCI with a rank of 2 for a PDSCH / PUSCH can result in the actual rank of the PDSCH / PUSCH (e.g., the number of transport layers) being 1.

[0332] Figure 39 Example 3900 is used for DM-RS port aggregation of single symbol type 1DM-RS.

[0333] The WTRU 102 can determine the PT-RS pattern. In one example, a PT-RS port can be supported to provide enhanced frequency domain channel estimation performance. Figure 40 Example 4000 of PT-RS above 52.6 GHz is shown to provide enhanced channel estimation performance in the frequency domain. Figure 40A comparison of PT-RS for FR2 with examples of PT-RS above 52.6 GHz is shown. For example... Figure 40 As shown in Example 4000, the PT-RS 4002 of FR2 may have an RS that simultaneously (e.g., only) occupies one subcarrier in the frequency domain across a resource block (RB). The PT-RS 4004 above 52.6 GHz may (e.g., the opposite of the PT-RS of FR2) occupy multiple subcarriers in the frequency domain and fewer REs in the time domain, which can improve the accuracy of DM-RS channel estimation for quasi-co-locating DM-RS ports to PT-RS ports. For example, higher time-domain RS density may not be necessary above 52.6 GHz due to the shorter time slot length.

[0334] WTRU 102 can determine the DM-RS used for slot binding and / or multi-slot scheduling. As shown below, DCI and side link control information (SCI) are used interchangeably. WTRU 102 can receive one or more DCIs for scheduling one or more transport blocks in one or more slots used for shared channels (e.g., PDSCH, PUSCH, and / or PSSCH). WTRU 102 can apply different DM-RS patterns for different scheduling types and / or different durations (e.g., micro-slots / slots / symbols). WTRU 102 can determine one or more DM-RS patterns based on one or more sets of DM-RS configurations.

[0335] WTRU 102 can receive one or more sets of DM-RS configurations (e.g., transmitted via RRC messages). The DM-RS configuration may include information indicating any of the following: DM-RS type, additional location, maximum length, PT-RS, scrambling ID, transform precoding enabled / disabled, narrowband PUSCH (nPUSCH) identifier, sequence and / or sequence group frequency hopping.

[0336] For example, WTRU 102 can receive configurations for any of Type 1 DM-RS, Type 2 DM-RS, and / or Enhanced DM-RS (e.g., for frequencies above 52.6 GHz). WTRU 102 can receive configurations for the location of additional DM-RS. WTRU 102 can receive configurations for the duration of a DM-RS, such as a pre-DM-RS, which can be specified as the number of symbols (e.g., the maximum number of OFDM symbols). WTRU 102 can receive configurations for one or more associated PT-RS configurations. WTRU 102 can receive configurations for one or more scrambling IDs for DM-RS. WTRU 102 can receive configurations with information indicating whether transform precoding (e.g., enabled / disabled) should be applied. WTRU 102 can receive configurations with information indicating the identifier of the PUSCH. WTRU 102 can receive configurations with information indicating either sequence frequency hopping and / or sequence group frequency hopping.

[0337] Based on one or more sets of DM-RS configurations, WTRU 102 can determine a set (e.g., a subset) of DM-RS configurations for receiving / transmitting one or more shared channels. WTRU 102 can determine a set (e.g., a subset) of DM-RS configurations based on any of the following: received indications, WTRU 102 reports, shared channel scheduling, scaling factors, duration, scheduling parameters, and / or transport blocks.

[0338] A set (e.g., subset) of DM-RS configurations to be used for receiving / transmitting one or more shared channels can be determined based on one or more indications (e.g., gNB indications) received via any of RRC, MAC CE, and / or DCI.

[0339] A set (e.g., subset) of DM-RS configurations can be determined based on WTRU 102 reports (e.g., ACK / NACK, CSI, PRACH). WTRU 102 can indicate a preferred subset (e.g., one or more) of the DM-RS configurations to be used by transmitting one or more ACK / NACKs. For example, the transmitted ACK / NACK may include information indicating at least one preferred DM-RS pattern. In another example, WTRU 102 can indicate a first DM-RS pattern by reporting an ACK and a second DM-RS pattern by reporting a NACK.

[0340] WTRU 102 can indicate a preferred subset (e.g., one or more) of the DM-RS configuration to be used by transmitting one or more CSI reports. For example, WTRU 102 can explicitly (e.g., based on indications via RRC and / or MAC CE) and / or implicitly (e.g., based on one or more configurations of the scheduled symbol, scheduled time slot, scheduling type, and / or associated DM-RS configuration for the CSI report) receive a CSI report configuration for a preferred DM-RS pattern. Based on the CSI report configuration, WTRU 102 can indicate the preferred pattern as information in the CSI report if the CSI report is configured (e.g., via RRC), activated (e.g., via MAC CE), and / or triggered (e.g., via DCI). The indication can be based on a preferred DM-RS pattern indicator (PDPI).

[0341] WTRU 102 can indicate a preferred subset (e.g., one or more) of the DM-RS configuration to be used by transmitting one or more PRACHs. WTRU 102 can transmit PRACHs in associated PRACH resources. For example, WTRU 102 can indicate a first DM-RS pattern by transmitting a PRACH in a first PRACH resource and indicate a second DM-RS pattern by transmitting a PRACH in a second PRACH resource.

[0342] WTRU 102 can receive, for example, an acknowledgment (e.g., a response) indicating the application of a reported DM-RS pattern from gNB 180 or other network access point. For the acknowledgment, WTRU 102 can receive a CORESET configuration for receiving the acknowledgment. WTRU 102 can apply the reported pattern after n+X, where n can be the timeslot used to acknowledge receipt, and X can be the timeslot offset used for pattern application.

[0343] A set (e.g., a subset) of DM-RS configurations can be determined based on the shared channel scheduling type. For example, WTRU102 can determine the DM-RS pattern based on the scheduling type (such as single transport block scheduling, multi-transport block scheduling, single timeslot scheduling, and / or multi-timeslot scheduling).

[0344] A set (e.g., subset) of DM-RS configurations can be determined based on a scaling factor (e.g., F) used for shared channel scheduling. WTRU 102 can receive at least one shared channel scaling factor F. For example, factor F can be applied as any of the following: (1) the minimum unit for allocation in the time domain can be F symbols; (2) the number of symbols per time slot (e.g., 14 × F symbols); (3) the maximum (e.g., maximum) number of time slots (or transmission time intervals) for a single shared channel (e.g., PDSCH and / or PUSCH) can be F time slots; (4) the minimum (e.g., minimum) unit for allocation in the frequency domain can be inversely proportional to F; (5) the number of subcarriers in a resource block can be a function of F (e.g., 12 / F subcarriers); (6) the number of symbols in a resource block (e.g., in the time domain) can be a function of F (e.g., ...). (e.g., 14×F symbols); (7) the set of symbols or resource elements in which DM-RS are mapped for channels (e.g., PDSCH, PUSCH and / or PUCCH) can be a function of F for a given DMRS mapping type (e.g., proportional to F); (8) the set of symbols or resource elements in which UCI can be multiplexed in PUSCH can be a function of F and / or can be relative to the set of symbols used for DM-RS; (9) the unit of any of the parameters K0, K1, K2 (e.g., the base of the time slot) can be proportional to F (e.g., when F = 2, a value of K0 = 3 can correspond to 6 time slots).

[0345] A set (e.g., subset) of the DM-RS configuration can be determined based on the duration (e.g., number of time slots and / or number of symbols) of the scheduled shared channels (e.g., PDSCH, PUSCH, and / or PSSCH). For example, WTRU 102 can receive DCIs that schedule one or more shared channels for a duration. When the duration is less than (or equal to) a threshold, WTRU 102 can use a first set of the DM-RS configuration to transmit / receive one or more shared channels. When the duration is greater than the threshold, WTRU 102 can use a second set of the DM-RS configuration to transmit / receive one or more shared channels. WTRU 102 can receive N thresholds, and WTRU 102 can be configured with N+1 sets of DM-RS configurations. Based on the N thresholds and the N+1 sets of DM-RS configurations, WTRU 102 can determine a set (e.g., subset) of the DM-RS configuration.

[0346] A set (e.g., subset) of the DM-RS configuration can be determined based on the number of scheduled transport blocks. For example, WTRU 102 can receive DCIs that schedule one or more shared channels comprising one or more transport blocks. When the number of one or more transport blocks is less than (or equal to) a threshold, WTRU 102 can use a first set of the DM-RS configuration to transmit / receive one or more shared channels. When the number of one or more transport blocks is greater than the threshold, WTRU 102 can use a second set of the DM-RS configuration to transmit / receive one or more shared channels. WTRU 102 can receive N thresholds, and WTRU 102 can be configured with N+1 sets of DM-RS configurations. Based on the N thresholds and the N+1 sets of DM-RS configurations, the UE can determine a set (e.g., subset) of the DM-RS configuration.

[0347] Control channel DM-RS enhancements can be provided. WTRU 102 can determine PDCCH DM-RS enhancements. The density of RS in the frequency domain is inversely proportional to the increase of SCS. Low RS density can reduce the channel estimation performance of PDCCH DM-RS in the frequency domain. Enhanced channel estimation performance of PDCCH DM-RS can be provided, for example, by gNB 180 and / or WTRU 102 supporting one or more of the following: frequency hopping of PDCCH DM-RS based on REG index and / or the type of REG with enhanced PDCCH DM-RS.

[0348] WTRU 102 determines the configuration of the PDCCH DM-RS enhancement. In one example, one or more PDCCH DM-RS types may be used. For example, the first PDCCH DM-RS type may be a single DM-RS pattern for (e.g., all) REGs configured in the CORESET. The second PDCCH DM-RS type may be based on one or more of the following, wherein the DM-RS pattern may be the RE position of the PDCCH DM-RS within the REG.

[0349] One or more DM-RS patterns may be used. For example, a DM-RS pattern may be determined based on at least one of the following (e.g., among multiple DM-RS patterns): OFDM symbol index, REG index, REG index within REG bundle, CCE index, search space identifier, CORESET identifier, BWP identifier, carrier identifier, subframe index, slot index, radio frame index, physical cell ID, SSB index, and / or WTRU related parameters (e.g., configuration identifier (id), WTRU identifier (e.g., C-RNTI, IMSI, sTMSI, etc.)).

[0350] A single DM-RS pattern can be used for (e.g., all) REGs configured in the CORESET. The density can be higher than the first PDCCH DM-RS type (e.g., more than three DM-RS REs per REG).

[0351] The first PDCCH DM-RS type may be referred to as normal PDCCH DM-RS, while the second PDCCH DM-RS type may be referred to as enhanced DM-RS for monitoring PDCCH (e.g., or enhanced PDCCH DM-RS).

[0352] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on RRC. In one example, the configuration of PDCCH DM-RS enhancements can be based on one or more RRC messages. For example, WTRU 102 can receive one or more RRC messages indicating the configuration of PDCCH DM-RS enhancements. The configuration can be based on, for example, WTRU, BWP, CORESET, CORESET group, and / or SS. WTRU 102 can (e.g., based on the configuration) receive enhanced DM-RS for monitoring PDCCH.

[0353] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on the configuration symbols or time slots of RRCs. In one example, the configuration of PDCCH DM-RS enhancements can be based on one or more RRC messages indicating whether one or more symbols and / or time slots are using PDCCH DM-RS enhancements. For example, WTRU 102 can receive one or more RRC messages indicating one or more symbols and / or time slots to be monitored, such as assuming PDCCH DM-RS enhancements are present. WTRU 102 can monitor PDCCH (e.g., based on one or more RRC messages), such as assuming PDCCH DM-RS enhancements are present in one or more symbols and / or time slots.

[0354] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on ALs. In one example, the configuration of PDCCH DM-RS enhancements can be based on multiple CCEs or ALs. For example, WTRU 102 can determine whether to use PDCCH DM-RS enhancements based on the number of CCEs or ALs.

[0355] The WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on the number of REGs in the REG bundle and / or the size of the REG bundle. For example, the WTRU 102 can determine whether to use PDCCH DM-RS enhancement based on the number of REGs or the size of the REG bundle in the CORESET used for PDCCH decoding.

[0356] WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on the DCI format. In one example, the configuration of PDCCH DM-RS enhancement can be based on the DCI format. WTRU 102 can determine whether to use PDCCH DM-RS enhancement, for example, based on the monitored DCI format. For example, if WTRU 102 is monitoring a fallback DCI format (e.g., DCI format 0_0 and / or DCI format 1_0), WTRU 102 can monitor the PDCCH without PDCCH DM-RS enhancement. For example, if WTRU 102 is monitoring a DCI format different from the fallback DCI format (e.g., DCI format 0_1 ​​and / or DCI format 1_1), WTRU 102 can monitor the PDCCH assuming PDCCH DM-RS enhancement is present.

[0357] WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on frequency band. In one example, the configuration of PDCCH DM-RS enhancement can be based on frequency band. For example, if the SS or CORESET (e.g., monitored by WTRU 102 via PDCCH) is located in FR1, WTRU 102 can monitor the PDCCH without PDCCH DM-RS enhancement. For example, if the SS or CORESET (e.g., monitored by WTRU 102) is located above 52.6 GHz, WTRU 102 can monitor the PDCCH assuming PDCCH DM-RS enhancement is present.

[0358] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on system bandwidth and / or bandwidth portion size. In one example, the configuration of PDCCH DM-RS enhancements can be based on system bandwidth or BWP size. For example, if WTRU 102 is monitoring SS or CORESET, WTRU 102 can determine whether to use PDCCH DM-RS enhancements based on system bandwidth and / or BWP size. For example, if the system bandwidth or BWP size of SS or CORESET is greater than a certain (e.g., a threshold) bandwidth, WTRU 102 can monitor PDCCH assuming PDCCH DM-RS enhancements are present. For example, if the system bandwidth or BWP size of SS or CORESET is less than or equal to a certain (e.g., a threshold) bandwidth, WTRU 102 can monitor PDCCH without PDCCH DM-RS enhancements. In another example, if the system bandwidth or BWP size of SS or CORESET is less than or equal to a threshold, WTRU 102 can monitor PDCCH assuming PDCCH DM-RS enhancements are present. If the system bandwidth of SS or CORESET or the BWP size is greater than the threshold, WTRU 102 can monitor PDCCH without PDCCH DM-RS enhancement.

[0359] WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on SCS. In one example, the configuration of PDCCH DM-RS enhancement can be based on SCS. For example, if WTRU 102 is monitoring SS or CORESET, WTRU 102 can determine whether to use PDCCH DM-RS enhancement based on the SCS of SS and / or CORESET. For example, if the SCS of SS or CORESET is greater than a specific (e.g., threshold) SCS, WTRU 102 can monitor PDCCH assuming PDCCH DM-RS enhancement is present. For example, if the SCS of SS or CORESET is less than a specific SCS, WTRU 102 can monitor PDCCH without PDCCH DM-RS enhancement.

[0360] WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on group DCI. In one example, the configuration of PDCCH DM-RS enhancement can be based on group DCI. For example, if WTRU 102 receives a group DCI indicating PDCCH DM-RS enhancement, WTRU 102 can monitor SS and / or CORESET assuming PDCCH DM-RS enhancement is present. The indication of the group DCI can be, for example, based on SS, based on CORESET, and / or based on the CORESET group.

[0361] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on SS type. In one example, the configuration of PDCCH DM-RS enhancements can be based on SS type. For example, WTRU 102 can receive one or more RRC messages that include one or more SS configurations. The one or more SS configurations can include, for example, an SS type for each of the one or more SS configurations. WTRU 102 can (e.g., based on SS type) determine whether to monitor PDCCH (e.g., assuming or not assuming PDCCH DM-RS enhancements). For example, if the SS type is a public SS, WTRU 102 can monitor PDCCH without PDCCH DM-RS enhancements. For example, if the SS type is a WTRU-specific SS, WTRU 102 can monitor PDCCH assuming PDCCH DM-RS enhancements.

[0362] WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on a combination of configuration methods, such as those described herein. The configuration of PDCCH DM-RS enhancement can be based on a combination of configuration methods, such as those described herein.

[0363] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on RRC and group DCI. In one example, the configuration can be based on RRC messages and group DCI indications. For example, WTRU 102 can receive one or more RRC messages indicating the configuration for PDCCH DM-RS enhancements for WTRU, SS, CORESET, and / or CORESET groups. WTRU 102 can (e.g., based on configuration) receive group DCIs indicating PDCCH DM-RS enhancements for PDCCH monitoring. WTRU 102 can monitor PDCCH under the assumption of PDCCH DM-RS enhancements (e.g., based on configuration and indications).

[0364] The WTRU 102 can determine the configuration of PDCCH DM-RS enhancement based on SCS and DCI. In one example, the configuration can be based on SCS and group DCI indication. For example, when the WTRU 102 monitors SS or CORESET, the SCS of SS and / or CORESET can be configured. For example, if the SCS is above an SCS threshold (e.g., 480 kHz or 960 kHz), the group DCI can indicate whether PDCCH DM-RS enhancement is used to monitor PDCCH in SS and / or CORESET.

[0365] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on the number of OFDM symbols configured for the CORESET. In one example, it can be determined whether to use enhanced DM-RS to monitor the PDCCH based on the number of OFDM symbols configured for the CORESET associated with the search space. For example, if an OFDM symbol is configured for the CORESET, WTRU 102 can utilize enhanced DM-RS for PDCCH monitoring to monitor the associated search space. WTRU 102 can (e.g., otherwise) utilize normal DM-RS for PDCCH monitoring to monitor the associated search space. For example, when the number of OFDM symbols is greater than a threshold, WTRU 102 can (e.g., alternatively) utilize enhanced DM-RS for PDCCH monitoring to monitor the associated search space. WTRU 102 can (e.g., otherwise) utilize normal DM-RS for PDCCH monitoring to monitor the associated search space.

[0366] WTRU 102 can determine the configuration of PDCCH DM-RS enhancements based on the slot bindings configured and / or indicated for the WTRU. For example, if a first granularity (e.g., slot or microslot) is configured for the WTRU, WTRU 102 can utilize the enhanced DM-RS for PDCCH monitoring to monitor the associated search space. WTRU 102 can (e.g., otherwise) utilize the normal DM-RS for PDCCH monitoring to monitor the associated search space. As another example, when the number of bound slots exceeds a threshold, WTRU 102 can utilize the enhanced DM-RS for PDCCH monitoring to monitor the associated search space. WTRU 102 can (e.g., otherwise) utilize the normal DM-RS for PDCCH monitoring to monitor the associated search space.

[0367] The WTRU 102 can determine the frequency hopping of the PDCCH DM-RS based on the REG index. In one example, frequency hopping of the PDCCH DM-RS can be supported. Figure 41 An example 4100 of frequency hopping for PDCCH DM-RS 4102 is shown. For example, WTRU 102 can receive a PDCCH with multiple REGs. Each of the multiple REGs 1004 can have a different frequency position for the PDCCH DM-RS. WTRU 102 can assume that the radio channel of PDCCH DM-RS 4102 remains unchanged and can jointly estimate PDCCH DM-RS 4102 in the frequency domain. For example, due to the increased PDCCH DM-RS density in the frequency domain, WTRU 102 can achieve better channel estimation performance for PDCCH DM-RS 4102. Figure 41As shown in the example, frequency hopping can be based on REG indices. For example, a PDCCH DM-RS4102 for REG 1 can be one RE away from a PDCCH DM-RS4102 for REG 0. A PDCCH DM-RS4102 for REG 2 can be two RE away from a PDCCH DM-RS4102 for REG 0 (and one RE away from a PDCCH DM-RS for REG 1). Frequency hopping of PDCCH DM-RS4102 can be based on one or more of the following: REG indices, REG bundle indices, aggregation levels of one or more related search spaces, the number of REGs in the CORESET, and the REG bundle size. For example, WTRU 102 can apply frequency hopping of PDCCH DM-RS4102 within a REG bundle.

[0368] Figure 41 Example 4100 of frequency hopping for PDCCH DM-RS 4102 is shown.

[0369] Enhanced PDDCH DM-RS can support one type of REG. In one example, REGs for enhanced PDDCH DM-RS can be supported. Figure 42 Example 4200 of REG for enhancing PDCCH DM-RS is shown. (e.g.) Figure 42 As shown in Example 4200, REG 1004 may have a higher RS ​​density than another REG. For example, REG 1004 may have four or more REs 1008 for PDCCHDM-RS 4102 in the REG to provide, for example, better channel estimation in the frequency domain.

[0370] Figure 42 Example 4200 of REG for enhancing PDCCH DM-RS 4102 is shown.

[0371] One or more types of REG 1004 can be used. A first type of REG 1004 may include a first number of REs from DM-RS, and a second type of REG 1004 may include a second number of REs from DM-RS. For example, a first type of REG may include three REs from DM-RS, and a second type of REG may include six REs from DM-RS. In one example, the type of REG may include zero REs from DM-RS.

[0372] The REG type can be determined based on one or more of the following: subcarrier spacing, operating frequency band, bandwidth, number of OFDM symbols configured for the associated CORESET, search space index, CORESET id, REG index, REG bundle index, CCE index, search space id, BWP-id, carrier index, higher layer configuration, and / or WTRU-specific parameters (such as WTRU-id).

[0373] REG 1004 can be used interchangeably with the second REG type.

[0374] WTRU 102 can determine that PDCCH DM-RS 4102 is skipped in some REGs. Figure 43 Example 4300 utilizes enhanced PDCCH DM-RS 4102 for PDCCH DM-RS skipping. For example, if WTRU 102 supports a second REG type with enhanced RS density in the frequency domain, a set of REGs may not transmit PDCCH DM-RS. Figure 43 Example 4300 of PDCCH DM-RS skipping utilizing enhanced PDCCH DM-RS 4102 is illustrated. For example, WTRU 102 may receive a configuration of CORESET. CORESET may include multiple REGs. WTRU 102 may determine a first group of REGs and a second group of REGs among the multiple REGs. The first group of REGs (e.g., REG 4302) may have enhanced PDCCH DM-RS 4102, while the second group of REGs (e.g., REG 4304 and / or 4306) may not have PDCCH DM-RS. WTRU 102 may monitor PDCCH, for example, based on the first and second groups. WTRU 102 may make the determination, for example, based on one or more of the REG index, the number of REGs in the CORESET, and / or the REG bundle size. For example, REGs with even-numbered REG indices may have enhanced PDCCH DM-RS 4102, while REGs with odd-numbered REG indices may not have PDCCH DM-RS. For example, it can support lower PDCCH DM-RS density instead of skipping PDCCH DM-RS transmission.

[0375] Figure 43 Example 4300 utilizes the enhanced PDCCH DM-RS 4102 to skip PDCCH DM-RS.

[0376] The WTRU 102 can use one or more PUCCH DM-RS types. Figure 44Examples 4400 include a PUCCH DM-RS 4402 with enhanced DM-RS frequency density and another PUCCH DM-RS 4404 without enhancement. For example, a first (e.g., enhanced PUCCH DM-RS 4402) PUCCH DM-RS type may include any of the following: a higher frequency density of PUCCH DM-RS 4402, frequency hopping of PUCCH DM-RS, and / or skipping of PUCCH DM-RS. A second PUCCH DM-RS type may be a PUCCH DM-RS 4404 without enhancement.

[0377] In some representative implementations, WTRU 102 may use an enhanced PUCCH DM-RS type, including PUCCH DM-RS 4402 with enhanced frequency density. For example, WTRU 102 may apply more REs in a PUCCH symbol than is used in another PUCCH DM-RS type. When WTRU 102 uses a PUCCH DM-RS type with enhanced frequency density, access points such as gNB 180 can assume the same channel in the time domain and can better estimate the channel in the frequency domain.

[0378] Figure 44 Examples include the PUCCH DM-RS 4402 with enhanced DM-RS frequency density and another example, the PUCCH DM-RS 4404 without enhancement, 4400.

[0379] In some representative implementations, WTRU 102 may use an enhanced PUCCH DM-RS type with frequency hopping, including PUCCH DM-RS 4402. For example, WTRU 102 may apply different frequency RE locations (e.g., REs 4502, 4504, 4506) of PUCCH DM-RS REs based on PUCCH time resources (e.g., symbols, micro-slots, and / or slots). Time resources may be continuous or discontinuous. When WTRU 102 uses an enhanced PUCCH DM-RS 4402 type with frequency hopping, including PUCCH DM-RS 4402, access points such as gNBs can assume the same channel in the time domain and can better estimate the channel in the frequency domain.

[0380] Figure 45 This is an example of frequency hopping 4500 for the PUCCH DM-RS 4402.

[0381] In some representative embodiments, WTRU 102 may use an enhanced PUCCH DM-RS type that includes PUCCH DM-RS and / or PUCCH DM-RS with enhanced frequency density. For example, WTRU 102 may not transmit PUCCH DM-RS RE, or may transmit PUCCH DM-RS RE at a lower frequency density in some PUCCH symbols (e.g., the first or more PUCCH symbols) in the PUCCH resource. WTRU 102 may transmit PUCCH DM-RS RE, or may transmit PUCCH DM-RS RE at a higher frequency density in other PUCCH symbols (e.g., the second or more PUCCH symbols) in the PUCCH resource.

[0382] Figure 46 Example 4600 is a PUCCH DM-RS skip and a PUCCH DM-RS with enhanced DM-RS frequency density.

[0383] The first PUCCH DM-RS type or pattern (e.g., one or more of PUCCH DM-RS with enhanced frequency density, PUCCH DM-RS frequency hopping, and PUCCH DM-RS skip / DM-RS with enhanced frequency domain density) may be referred to as Enhanced PUCCH DM-RS 4602. The second PUCCH DM-RS type or pattern may be referred to as Normal PUCCH DM-RS 4604.

[0384] WTRU 102 can determine the DM-RS type used for PUCCH transmission based on any of the following: explicit indication, implicit indication, duration, PUCCH format, PUCCH type, UCI, DM-RS multiplexing type, PUCCH frequency resources, additional DM-RS configuration, system bandwidth, BWP size, SCS, slot binding, number of slots, interleaving allocation, and / or intra-slot frequency hopping.

[0385] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on indications (e.g., explicit and / or implicit indications) from a network access point such as gNB 180. For example, WTRU 102 can receive an indication from gNB 180 via any of RRC, MAC CE, and / or DCI. This indication can indicate whether enhanced PUCCH DM-RS is used. Based on this indication, the UE can transmit one or more PUCCHs with enhanced PUCCH DM-RS. The DCI can be a group DCI. For example, when WTRU 102 receives a group DCI indicating enhanced PUCCH DM-RS, WTRU 102 can apply enhanced PUCCH DM-RS to (e.g., any applicable) PUCCH resources and / or PUCCH formats. The indication of the group DCI can be based on PUCCH resources, PUCCH resource groups, BWP, and / or WTRU.

[0386] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on the configured duration. The duration can be the number of symbols, microslots, and / or slots used for PUCCH transmission. For example, WTRU 102 can receive one or more RRC messages indicating the duration (e.g., the number of symbols / microslots / slots) used for PUCCH transmission. If the duration is less than (or equal to) a threshold, WTRU 102 can determine a first DM-RS pattern (e.g., normal PUCCH DM-RS) for PUCCH transmission. If the duration is greater than the threshold, WTRU 102 can determine a second DM-RS pattern (e.g., enhanced PUCCH DM-RS).

[0387] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on the PUCCH format and / or PUCCH type. For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on the configured PUCCH format for the PUCCH resource. For example, when WTRU 102 is transmitting a PUCCH with a first PUCCH format and / or a first PUCCH type (e.g., any of PUCCH format 0, PUCCH format 1, and / or short PUCCH), WTRU 102 can transmit a PUCCH with normal PUCCH DM-RS. When WTRU 102 is transmitting a second PUCCH format and / or a second PUCCH type (e.g., any of PUCCH format 2, PUCCH format 3, PUCCH format 4, and / or long PUCCH), WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS.

[0388] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on the UCI and / or DM-RS multiplexing type. For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on the UCI and / or DM-RS multiplexing type used for the PUCCH format. For example, when WTRU 102 wants to transmit a first PUCCH format with a first multiplexing type (e.g., TDM), WTRU 102 can transmit a PUCCH with normal PUCCH DM-RS. When WTRU 102 wants to transmit a second PUCCH format with a second multiplexing type (e.g., FDM), WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS.

[0389] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on PUCCH resources and / or frequency resources of the PUCCH format. For example, the frequency resources can be multiple PRBs. For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on PUCCH resources and / or frequency resources of the PUCCH format. For example, WTRU 102 can receive one or more RRC messages indicating the frequency resources (e.g., the number of PRBs) used for PUCCH transmission. If the size of the frequency resources (e.g., the number of PRBs) is less than (or equal to) a threshold, WTRU 102 can determine a first DM-RS pattern (e.g., normal PUCCH DM-RS) for PUCCH transmission. If the size of the frequency resources is greater than the threshold, WTRU 102 can determine a second DM-RS pattern (e.g., enhanced PUCCH DM-RS).

[0390] For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on the available frequency resources for the configured PUCCH format used for PUCCH resources. For instance, when WTRU 102 will transmit a first PUCCH format (e.g., any one of PUCCH format 0, PUCCH format 1, and / or PUCCH format 4) with a first number of PRBs (e.g., one PRB), WTRU 102 can transmit a PUCCH with normal PUCCH DM-RS. When WTRU 102 will transmit a second PUCCH format (e.g., any one of PUCCH format 2 and / or PUCCH format 3) with a second number of PRBs (e.g., two or more PRBs), WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS.

[0391] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on the additional DM-RS configuration. For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on the additional DM-RS configuration used for the PUCCH format. For example, when WTRU 102 wants to transmit a first PUCCH format with additional DM-RS, WTRU 102 can transmit a PUCCH with normal PUCCH DM-RS. When WTRU 102 wants to transmit a second PUCCH format without additional DM-RS, WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS (e.g., enhanced frequency domain density). In another example, when WTRU 102 wants to transmit a first PUCCH format without additional DM-RS, WTRU 102 can transmit a PUCCH with normal PUCCH DM-RS. When WTRU 102 needs to transmit a second PUCCH format with additional DM-RS, WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS (e.g., frequency hopping).

[0392] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on system bandwidth and / or BWP. For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on system bandwidth and / or BWP size. For example, when WTRU 102 is to transmit one or more PUCCHs, WTRU 102 can determine whether to use PUCCH DM-RS enhancement based on system bandwidth or BWP size. For example, when the system bandwidth or BWP size of WTRU 102 (e.g., DL or UL) is greater than a threshold, WTRU 102 can transmit PUCCHs without enhanced PUCCH DM-RS. When the system bandwidth or BWP size of WTRU 102 is less than or equal to the threshold, WTRU 102 can transmit PUCCHs with enhanced PUCCH DM-RS.

[0393] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on SCS. For example, WTRU 102 can determine whether to apply enhanced PUCCH DM-RS based on the SCS of the BWP (e.g., uplink or downlink) and / or PUCCH resources, such as when WTRU 102 is monitoring SS and / or CORESET. For example, if the SCS of the BWP and / or PUCCH resources is greater than a threshold, WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS. If the SCS of the BWP and / or PUCCH resources is less than or equal to the threshold, WTRU 102 can transmit a PUCCH with normal PUCCH DM-RS.

[0394] WTRU 102 can determine the configuration of PUCCH DM-RS enhancement based on slot binding and / or multiple slots used for scheduling the shared channel. For example, WTRU 102 can determine whether to use enhanced PUCCH DM-RS based on slot binding and / or multiple slots used for scheduling the shared channel. For example, when WTRU 102 is to transmit one or more PUCCHs, WTRU 102 can determine whether to use PUCCH DM-RS enhancement based on the use of slot binding or the number of slots used for scheduling. For example, when WTRU 102 receives a DCI scheduling a number of bound slots greater than a threshold, WTRU 102 can transmit a PUCCH without enhanced PUCCH DM-RS. When WTRU 102 receives a DCI scheduling a number of bound slots less than or equal to a threshold, WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS.

[0395] WTRU 102 can determine the PUCCH DM-RS enhancement configuration based on the configuration of the interleaving allocation of PUCCH resources and / or PUCCH formats. For example, when WTRU 102 needs to transmit one or more PUCCHs with a first PUCCH format and / or a first PUCCH resource using interleaving allocation, WTRU 102 can transmit one or more PUCCHs with normal PUCCH DM-RS. When WTRU 102 needs to transmit one or more PUCCHs with a second PUCCH format and / or a second PUCCH resource not using interleaving allocation, WTRU 102 can transmit PUCCHs with enhanced PUCCH DM-RS.

[0396] WTRU 102 can determine the PUCCH DM-RS enhancement configuration based on the intra-slot frequency hopping configuration. For example, when WTRU 102 is to transmit one or more PUCCHs with a first PUCCH format and / or a first PUCCH resource using intra-slot frequency hopping, WTRU 102 can transmit one or more PUCCHs with normal PUCCH DM-RS. When WTRU 102 is transmitting a second PUCCH format and / or a second PUCCH resource without intra-slot frequency hopping, WTRU 102 can transmit a PUCCH with enhanced PUCCH DM-RS.

[0397] Figure 47 This is an exemplary process that can be implemented by WTRU 102 for decoding PDDCH transmissions with DM-RS using frequency hopping or density variations. For example... Figure 47As shown, WTRU 102 can implement process 4700 to decode a PDDCH transmission with DM-RS using frequency hopping or density variations. Process 4700 can begin at 4710, where WTRU 102 receives (e.g., from gNB 180 or a similar entity) information indicating the CORESET configuration. The CORESET configuration may include symbol duration and / or indications of PDDCH DM-RS frequency hopping or density variations. At 4720, WTRU 102 can continue to receive information indicating the search space configuration of the search space associated with the CORESET. The search space configuration may include one or more DCI formats to be monitored and / or one or more aggregation levels associated with each of the one or more DCI formats. The reception at 4710 and / or 4720 can be performed, for example, according to the techniques described herein. At 4730, WTRU 102 can determine multiple DM-RS locations in one or more REGs of the CORESET and / or the search space associated with the CORESET. After 4730, WTRU 102 may receive PDCCH transmissions in the search space associated with CORESET at 4740. At 4750, WTRU 102 performs decoding of the received PDCCH transmissions using one or more PDCCH DM-RSs from the determined DM-RS locations. After 4750, at 4760, WTRU 102 may continue to receive PDSCH transmissions or send PUSCH transmissions based on one or more DCI fields of the decoded PDCCH transmissions.

[0398] Figure 48 This is an exemplary process that can be implemented by a RAN entity for transmitting PDDCH transmissions with DM-RS using frequency hopping or density variations. For example... Figure 48As shown, a RAN entity (e.g., gNB 180 or a similar entity) may implement process 4800 for transmitting PDDCH transmissions with DM-RS using frequency hopping or density variations. Process 4800 may begin at 4810, where the RAN entity transmits (e.g., to the WTRU) information indicating the CORESET configuration. The CORESET configuration may include indications of symbol duration and / or PDDCH DM-RS frequency hopping or density variations. At 4820, the RAN entity may continue transmitting information indicating the search space configuration associated with the CORESET. The search space configuration may include one or more DCI formats monitored by the WTRU 102 and / or one or more aggregation levels associated with each of the one or more DCI formats. The transmissions (e.g., transfers) at 4710 and / or 4720 may be performed, for example, according to the techniques described herein. Following step 4820, the RAN entity may transmit PDCCH transmissions in the search space associated with the CORESET, wherein one or more PDCCH DM-RSs for the PDCCH transmissions are located in multiple DM-RS locations associated with the CORESET configuration and / or search space configuration. For example, the RAN entity may receive a PUSCH transmission or send a PDSCH transmission to WTRU 102 after step 4830 based on the DCI (e.g., scheduled by the DCI) of the PDDCH transmission at 4830.

[0399] In some representative implementations, multiple DM-RS locations for the PDCCH DM-RS (e.g., in one or more REGs within the CORESET and / or the search space associated with the CORESET) may be determined based on: (1) an indication (e.g., frequency hopping or density variation), symbol duration, one or more DCI formats, and / or one or more aggregation levels; and (2) the corresponding REG index for each REG in the one or more REGs. For example, Figure 6 Example 600 of PDCCH 606 ​​is shown, and Figure 10 Example 1000 of CORESET 1002, REG 1004 and RE 1008 are shown.

[0400] In some representative embodiments, multiple DM-RS locations may be located in at least the first REG with the lowest corresponding REG index in (e.g., one or more) REGs within the CORESET and / or search space associated with the CORESET. For example, Figure 41 and Figure 43 Examples of frequency hopping for the PDCCH DM-RS 4102, 4100-4300, are shown. For example, in... Figure 41In this context, the PDCCH DM-RS 4102 of REG 1 can be 1 RE away from the PDCCH DM-RS 4102 of REG 0. The PDCCH DM-RS 4102 of REG 2 can be 2 RE away from the PDCCH DM-RS 4102 of REG 0 (e.g., and 1 RE away from the PDCCH DM-RS of REG 1). For example, in... Figure 43 In this context, REGs with even-numbered REG indices may have enhanced PDCCH DM-RS 4102, while REGs with odd-numbered REG indices may not have PDCCH DM-RS (e.g., no PDCCH DM-RS is located in an RE associated with an odd-numbered REG index). For example, lower PDCCH DM-RS density may be supported instead of skipping PDCCH DM-RS transmissions. One or more representative criteria and / or conditions described herein may be used to determine the location of PDCCH DM-RS.

[0401] Figure 49 This is an exemplary procedure that can be implemented by WTRU 102 for triggering DM-RS enhancements for PDSCH and / or PUSCH transmissions. For example... Figure 49As shown, WTRU 102 can implement process 4900 to trigger DM-RS enhancement for either PDSCH or PUSCH transmissions. Process 4900 can begin at 4910, where WTRU 102 receives (e.g., from gNB180 or a similar entity) information indicating the configuration of one or more resource sets, a first DCI field, and a second DCI field. For example, the information indicating the configuration can be received via any of RRC, MAC CE, and / or DCI. The one or more resource sets configured can include any of a CSI-RS resource set and / or an SRS resource set. The CSI-RS resource set can include aperiodic CSI-RS resources (e.g., an AP CSI-RS resource set). The SRS resource set can include aperiodic SRS resources (e.g., an AP SRS resource set). At 4920, WTRU 102 can continue to receive (e.g., from gNB 180 or a similar entity) PDCCH transmissions. At 4930, the PDCCH transmissions can be decoded. At 4940, provided that the decoded PDCCH transmission includes a DCI that schedules the PDSCH transmission, at least one aperiodic demodulation reference signal (DM-RS) for the PDSCH transmission can be triggered (e.g., at the WTRU) based on information indicated by the first DCI field of the decoded PDCCH transmission. For example, the aperiodic DM-RS may use the same resources and / or signals as the aperiodic CSI-RS and / or SRS described herein. The first DCI field may be a CSI request field. The CSI request field may trigger WTRU 102 to determine one or more CSI-RS resource sets (e.g., associated with one or more CSI reporting configurations) for any additional DM-RS. From 4940, WTRU 102 may continue receiving PDSCH transmissions at 4950 (e.g., from a gNB or similar entity) based on the (e.g., one or more) aperiodic DM-RS for the PDSCH transmission, using at least one resource set from the one or more resource sets (e.g., the determined resource set). After receiving a PDSCH transmission, the WTRU102 can continue decoding the PDSCH transmission using the aperiodic DM-RS used for PDSCH transmission.

[0402] At 4960, provided that the PDCCH transmission includes a DCI that schedules the PUSCH transmission, at least one aperiodic DM-RS for the PUSCH transmission can be triggered (e.g., at the WTRU) based on information indicated by the second DCI field of the decoded PDCCH transmission. For example, the second DCI field could be an SRS request field. The SRS request field can trigger WTRU 102 to determine one or more SRS resource sets (e.g., AP SRS resource sets activated by the SRS field) for any additional DM-RS. From 4960, WTRU 102 can continue transmitting PUSCH transmissions at 4970 (e.g., from gNB 180 or a similar entity) via (e.g., one or more) aperiodic DM-RSs for the PUSCH transmission, using at least one resource set from the one or more resource sets.

[0403] In some representative embodiments, WTRU 102 may omit any of 4940 to 4970. This omission may be based on whether one of the first DCI fields or the second DCI field is absent in the configuration at 4910. In some representative embodiments, WTRU 102 may omit the processing associated with PUSCH transmission (e.g., 4960 and 4970) upon receiving an indication of the first DCI field. In other representative embodiments, WTRU 102 may omit the processing associated with PDSCH transmission (e.g., 4940 and 4950) upon receiving an indication of the second DCI field.

[0404] Figure 50 This is an exemplary procedure that can be implemented by a RAN entity to trigger DM-RS enhancements at WTRU 102 for PDSCH and / or PUSCH transmissions. (Example:) Figure 50As shown, a RAN entity (e.g., gNB 180 or a similar entity) may implement process 5000 to trigger DM-RS enhancement for either PDSCH or PUSCH transmissions. Process 5000 may begin at 5010, where the RAN entity sends information indicating the configuration of one or more resource sets, a first downlink control information (DCI) field, and a second DCI field. For example, the information indicating the configuration may be received via any of RRC, MAC CE, and / or DCI. The configured one or more resource sets may include any of a CSI-RS resource set and / or an SRS resource set. The CSI-RS resource set may include aperiodic CSI-RS resources (e.g., an AP CSI-RS resource set). The SRS resource set may include aperiodic SRS resources (e.g., an AP SRS resource set). After 5010, at 5020, the RAN entity may continue sending PDCCH transmissions including the DCI. At 5030, under the condition that DCI schedules PDSCH transmissions, the RAN entity may continue to transmit (e.g., as scheduled) PDSCH transmissions with AP DM-RSs for PDSCH transmissions. The RAN entity may transmit (e.g., one or more) AP DM-RSs for PDSCH transmissions using (e.g., configured) at least one resource set from the first DCI field of the PDCCH transmission. For example, the first DCI field may be a CSI request field. The CSI request field may trigger WTRU 102 to determine one or more CSI-RS resource sets for any additional DM-RS (e.g., associated with one or more CSI report configurations). As another example, the second DCI field may be an SRS request field. The SRS request field may trigger WTRU 102 to determine one or more SRS resource sets for any additional DM-RS (e.g., AP SRS resource sets activated by the SRS field). At 5040, under the condition that DCI schedules PUSCH transmissions, the RAN entity may continue to receive (e.g., as scheduled) PUSCH transmissions with AP DM-RSs for PUSCH transmissions. The RAN entity may send (e.g., one or more) AP DM-RS for PUSCH transmission using at least one resource set in a (e.g., configured) resource set, based on the second DCI field of the PDCCH transmission.

[0405] In some representative embodiments, 5030 or 5040 may be omitted. This omission may be based on whether one of the first DCI field or the second DCI field is present / absent in the configuration at 5010. In some representative embodiments, the processing associated with PUSCH transmission (e.g., 5040) may be omitted upon the transmission of an indication of the first DCI field. In other representative embodiments, the processing associated with PDSCH transmission (e.g., 5030) may be omitted upon the transmission of an indication of the second DCI field.

[0406] This article describes an example of an additional DM-RS with AP CSI-RS for PDSCH and PUSCH decoding, such as reference Figure 13 and Figure 14 This article describes an example of using an additional DM-RS for SRS used in PDSCH and PUSCH decoding, such as reference Figure 18 and Figure 19 .

[0407] Figure 51 This is an exemplary procedure that can be implemented by WTRU 102 for receiving PDSCH transmissions using modulation and coding scheme (MCS) thresholding and DM-RS frequency hopping. For example... Figure 51 As shown, WTRU 102 can implement process 5100 to receive and decode PDSCH transmissions. Process 5100 may begin at 5110 with WTRU 102 (e.g., from gNB 180 or a similar entity) receiving information indicating a configuration, which includes an indication of demodulation reference signal (DM-RS) frequency hopping and an MCS threshold. Then, at 5120, WTRU 102 may continue receiving PDCCH transmissions. At 5130, WTRU 102 may perform decoding of the PDCCH transmission. If the decoded PDCCH transmission includes downlink control information (DCI) scheduling the PDSCH transmission, at 5140, WTRU 102 may continue to determine whether the MCS used for the PDSCH transmission exceeds the MCS threshold. If the MCS used for the PDSCH transmission exceeds the MCS threshold, at 5150, WTRU 102 may continue to determine multiple frequency positions of one or more DM-RSs used for the PDSCH transmission based on the indication. Following 5150, at 5160, WTRU 102 may continue to receive (e.g., according to a schedule) PDSCH transmissions with (e.g., one or more) DM-RS for PDSCH transmission. WTRU 102 may also perform reception of one or more DM-RS for PDSCH transmission at the determined frequency location. WTRU 102 may use the one or more DM-RS for PDSCH transmission received at the determined frequency location at 5160 to perform decoding of the PDSCH transmission.

[0408] Figure 52 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using MCS thresholds and DM-RS frequency hopping. For example... Figure 52 As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 5200 to transmit PDSCH transmissions. Process 5200 can begin at 5210 with the RAN entity transmitting information indicating a configuration, including an indication of demodulation reference signal (DM-RS) frequency hopping and a modulation and coding scheme (MCS) threshold. The RAN entity can then continue transmitting PDSCH transmissions. At 5230, provided the PDSCH transmission includes downlink control information (DCI) scheduling the PDSCH transmission, the RAN entity can determine whether the MCS used for PDSCH transmission exceeds the MCS threshold. At 5240, if the MCS used for PDSCH transmission exceeds the MCS threshold, multiple frequency locations of one or more DM-RSs used for PDSCH transmission are determined based on the indication. Then, at 5250, the RAN entity can continue transmitting PDSCH transmissions (e.g., according to scheduling) with (e.g., one or more) DM-RSs used for PDSCH transmission at the determined frequency locations.

[0409] Figure 53 This is an exemplary process that can be implemented by WTRU 102 for sending PUSCH transmissions using MCS thresholding and DM-RS frequency hopping. For example... Figure 53 As shown, WTRU 102 can perform process 5300 to receive and decode PUSCH transmissions. Process 5300 may begin at 5310 with WTRU 102 receiving (e.g., from gNB 180 or a similar entity) information indicating a configuration, which includes an indication of demodulation reference signal (DM-RS) frequency hopping and a modulation and coding scheme (MCS) threshold. Then, at 5320, WTRU 102 may continue to receive PDCCH transmissions. At 5130, WTRU 102 may perform decoding of the PDCCH transmission. If the decoded PDCCH transmission includes downlink control information (DCI) scheduling the PUSCH transmission, at 5340, WTRU 102 may continue to determine whether the MCS used for the PUSCH transmission exceeds the MCS threshold. If the MCS used for the PUSCH transmission exceeds the MCS threshold, at 5350, WTRU 102 may continue to determine multiple frequency positions of one or more DM-RSs used for the PUSCH transmission based on the indication. After 5350, at 5360, WTRU 102 may continue to transmit (e.g., according to schedule) PUSCH transmissions with (e.g., one or more) DM-RS for PUSCH transmissions at the determined frequency position.

[0410] Figure 54 This is an exemplary procedure that can be implemented by a RAN entity for receiving PUSCH transmissions using MCS thresholds and DM-RS frequency hopping. For example... Figure 54 As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 5400 to receive PUSCH transmissions. Process 5400 can begin at 5410 with the RAN entity sending information indicating a configuration, including an indication of demodulation reference signal (DM-RS) frequency hopping and a modulation and coding scheme (MCS) threshold. Afterwards, the RAN entity can continue sending PDCCH transmissions. At 5430, provided the PDCCH transmission includes downlink control information (DCI) scheduling the PUSCH transmission, at 5230, the RAN entity can determine whether the MCS used for the PUSCH transmission exceeds the MCS threshold. At 5440, provided the MCS used for the PUSCH transmission exceeds the MCS threshold, multiple frequency locations of one or more DM-RSs used for the PUSCH transmission are determined based on the indication. Then, at 5450, the RAN entity can continue receiving (e.g., according to scheduling) PUSCH transmissions with (e.g., one or more) DM-RSs used for PDSCH transmission at the determined frequency locations. The PUSCH transmission can then be decoded based on one or more received DM-RS.

[0411] In some representative implementations, the MCS used for PUSCH and / or PDSCH may be higher than (e.g., exceed) the SCS threshold (e.g., 480 kHz or 960 kHz). For example, the determined frequency location may be used to receive and / or transmit higher-density DM-RS as described herein. WTRU 102 may determine the RE (e.g., frequency location) for receiving and / or transmitting higher-density DM-RS. For example, the DM-RS may be a single-symbol or dual-symbol DM-RS.

[0412] Figure 55 This is an exemplary procedure that can be implemented by WTRU 102 for receiving PDSCH transmissions using a subcarrier spacing (SCS) threshold and DM-RS frequency hopping. For example... Figure 55As shown, WTRU 102 can implement process 5500 to receive and decode PDSCH transmissions. Process 5500 may begin at 5510 with WTRU 102 (e.g., from gNB 180 or a similar entity) receiving information indicating a configuration, which includes an indication of demodulation reference signal (DM-RS) frequency hopping and a subcarrier spacing (SCS) threshold. Then, at 5520, WTRU 102 may continue receiving PDCCH transmissions. At 5530, WTRU 102 may perform decoding of the PDCCH transmission. If the decoded PDCCH transmission includes downlink control information (DCI) scheduling the PDSCH transmission, at 5540, WTRU 102 may continue to determine whether the SCS used for the PDSCH transmission exceeds the SCS threshold. If the SCS used for the PDSCH transmission exceeds the SCS threshold, at 5550, WTRU 102 may continue to determine multiple frequency positions of one or more DM-RSs used for the PDSCH transmission based on the indication. After 5550, at 5560, WTRU 102 may continue to receive (e.g., according to scheduling) PDSCH transmissions with (e.g., one or more) DM-RS (e.g., according to scheduling) and use the DM-RS for PDSCH transmissions to decode the PDSCH transmissions at the determined frequency location.

[0413] Figure 56 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using SCS thresholds and DM-RS frequency hopping. For example... Figure 56 As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 5600 to transmit PDSCH transmissions. Process 5600 can begin at 5610 with the RAN entity transmitting information indicating a configuration, including an indication of demodulation reference signal (DM-RS) frequency hopping and an SCS threshold. Then, at 5620, the RAN entity can continue transmitting PDCCH transmissions. At 5630, provided the PDCCH transmission includes downlink control information (DCI) scheduling the PDSCH transmission, the RAN entity can determine whether the SCS used for the PDSCH transmission exceeds the SCS threshold. At 5640, provided the SCS used for the PDSCH transmission exceeds the SCS threshold, multiple frequency positions of one or more DM-RSs used for the PDSCH transmission are determined based on the indication. Then, at 5650, the RAN entity can continue transmitting (e.g., according to scheduling) PDSCH transmissions with (e.g., one or more) DM-RSs used for the PDSCH transmission. At 5650, the RAN entity can transmit one or more DM-RS for PDSCH transmission at the determined frequency location.

[0414] Figure 57This is an exemplary process that can be implemented by WTRU 102 for sending PUSCH transmissions using SCS thresholds and DM-RS frequency hopping. For example... Figure 57 As shown, WTRU 102 can implement process 5700 to receive and decode PUSCH transmissions. Process 5700 may begin at 5710 with WTRU 102 (e.g., from gNB 180 or a similar entity) receiving information indicating a configuration, which includes an indication of demodulation reference signal (DM-RS) frequency hopping and an SCS threshold. Then, at 5720, WTRU 102 may continue to receive PDCCH transmissions. At 5730, WTRU 102 may perform decoding of the PDCCH transmission. If the decoded PDCCH transmission includes downlink control information (DCI) scheduling the PUSCH transmission, at 5740, WTRU 102 may continue to determine whether the SCS used for the PUSCH transmission exceeds the SCS threshold. If the SCS used for the PUSCH transmission exceeds the SCS threshold, at 5750, WTRU 102 may continue to determine multiple frequency positions of one or more DM-RSs used for the PUSCH transmission based on the indication. After 5750, at 5760, WTRU 102 may continue to transmit (e.g., according to schedule) PUSCH transmissions with (e.g., one or more) DM-RS for PUSCH transmission (e.g., according to schedule). At 5760, WTRU 102 may perform transmission of one or more DM-RS for PUSCH transmission at the determined frequency location.

[0415] Figure 58 This is an exemplary procedure that can be implemented by a RAN entity for receiving PUSCH transmissions using SCS thresholds and DM-RS frequency hopping. For example... Figure 58As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 5800 to transmit PDSCH transmissions. Process 5800 can begin at 5810 with the RAN entity transmitting information indicating a configuration, including an indication of demodulation reference signal (DM-RS) frequency hopping and an SCS threshold. Then, at 5820, the RAN entity can continue transmitting PDCCH transmissions. At 5830, provided the PDCCH transmission includes downlink control information (DCI) scheduling PUSCH transmissions, the RAN entity can determine whether the SCS used for PUSCH transmissions exceeds the SCS threshold. At 5840, if the SCS used for PUSCH transmissions exceeds the SCS threshold, the RAN entity can perform a determination of multiple frequency positions of one or more DM-RSs used for PUSCH transmissions based on the indication. Then, at 5850, the RAN entity can continue receiving (e.g., according to scheduling) PUSCH transmissions with (e.g., one or more) DM-RSs used for PUSCH transmissions. At 5850, the RAN entity can perform reception of one or more DM-RS for PUSCH transmission at the determined frequency location. The PUSCH transmission can then be decoded based on the received DM-RS.

[0416] In some representative implementations, the SCS used for PUSCH and / or PDSCH may be higher than (e.g., exceed) an SCS threshold (e.g., 480 kHz or 960 kHz). For example, the determined frequency location may be used to receive and / or transmit higher-density DM-RS as described herein. WTRU 102 may determine the RE (e.g., frequency location) for receiving and / or transmitting higher-density DM-RS. For example, the DM-RS may be a single-symbol or dual-symbol DM-RS.

[0417] In some representative implementations, WTRU 102 can be configured with SCS thresholds and MCS thresholds as part of the same configuration. For example, if SCS thresholds and MCS thresholds are received, the aforementioned procedures for PUSCH and / or PDSCH transmissions can be combined. For example, SCS thresholds and / or MCS thresholds can be notified to WTRU 102 in one or more configurations via any of RRC messages, MAC CE, and / or DCI.

[0418] Figure 59 This is an exemplary procedure that can be implemented by WTRU 102 for receiving PDSCH transmissions aggregated using DM-RS ports. For example... Figure 59As shown, WTRU 102 can implement process 5900 to receive and decode PDSCH transmissions. Process 5900 can begin at 5910 with WTRU 102 receiving information indicating the aggregation of multiple demodulation reference signal (DM-RS) ports. Then, at 5920, WTRU 102 can continue to receive (e.g., according to a schedule) PDSCH transmissions with (e.g., one or more) DM-RSs for PDSCH transmission. At 5920, WTRU 102 can perform the aggregation of one or more DM-RSs for PDSCH transmission from the multiple DM-RS ports based on the indication. At 5930, WTRU 102 can perform decoding of the PDSCH transmission using the one or more DM-RSs received from the aggregation of the multiple DM-RS ports based on the indication.

[0419] Figure 60 This is an exemplary process that can be implemented by a RAN entity for sending PDSCH transmissions using DM-RS port aggregation. For example... Figure 60 As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 6000 to send PDSCH transmissions. Process 6000 can begin at 6010 with the RAN entity sending information indicating the aggregation of multiple DM-RS ports. At 6020, the RAN entity can continue sending (e.g., according to a schedule) PDSCH transmissions with (e.g., one or more) DM-RSs for PDSCH transmissions. At 6020, the RAN entity can perform the aggregation of multiple DM-RS ports based on the indication to send one or more DM-RSs for PDSCH transmissions.

[0420] Figure 61 This is an exemplary process that can be implemented by WTRU 102 for sending PUSCH transmissions using DM-RS port aggregation. For example... Figure 61 As shown, WTRU 102 can implement process 6100 to transmit PUSCH transmissions. Process 6100 can begin at 6110 with WTRU 102 receiving information indicating the aggregation of multiple demodulation reference signal (DM-RS) ports. Then, at 6120, WTRU 102 can continue transmitting (e.g., according to a schedule) PUSCH transmissions with (e.g., one or more) DM-RSs for PUSCH transmission. At 6120, WTRU 102 can perform the transmission of one or more DM-RSs for PUSCH transmissions from the aggregation of multiple DM-RS ports based on the indication.

[0421] Figure 62 This is an exemplary process that can be implemented by a RAN entity for receiving PUSCH transmissions aggregated using DM-RS ports. For example... Figure 62As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 6200 to receive PUSCH transmissions. Process 6200 can begin at 6210 with the RAN entity sending information indicating the aggregation of multiple demodulation reference signal (DM-RS) ports. Then, at 6220, the RAN entity can continue to receive (e.g., according to a schedule) PUSCH transmissions with (e.g., one or more) DM-RSs for PUSCH transmission. At 6220, the RAN entity can perform aggregation reception of one or more DM-RSs for PUSCH transmissions based on the indication. At 6230, the RAN entity can use the one or more DM-RSs received from the aggregation of multiple DM-RS ports to perform decoding of the PUSCH transmissions.

[0422] In some representative implementations, DM-RS symbols in the DM-RS port can be transmitted at different frequency locations. Figures 34 to 38 An example of frequency hopping as described herein is shown. For example, in... Figure 33 and Figure 34 In this configuration, the two DM-RS symbols in the DM-RS port are located at different frequency positions in order to achieve enhanced channel estimation in the frequency domain.

[0423] In some representative implementations, two or more DM-RS ports can be aggregated to provide enhanced channel estimation of DM-RS in the frequency domain. For example, DM-RS ports from different frequency locations or different CDM groups can be aggregated to achieve enhanced channel estimation in the frequency domain. Figure 39 In this system, DM-RS ports #0 and #2 from different frequency locations or different CDM groups can be aggregated. The aggregated DM-RS ports can be used for demodulation (e.g., downlink) transmission at the same layer. The same precoder can be used for transmission (e.g., uplink) of the aggregated DM-RS ports.

[0424] In some representative implementations, a transmission with a given rank (e.g., rank 2) (e.g., a scheduled PDSCH or PUSCH transmission) can use the aggregated DM-RS port. The actual rank of the transmission can be a lower rank (e.g., rank 1).

[0425] Figure 63 This is an exemplary process that can be implemented by WTRU 102 for receiving PDSCH transmissions using higher-density DM-RS. For example... Figure 63As shown, WTRU 102 can implement process 6300 to receive PDSCH transmissions. Process 6300 can begin at 6310 with WTRU 102 receiving information indicating antenna port configuration. Then, at 6320, WTRU 102 can continue to determine multiple DM-RS locations corresponding to consecutive resource elements on the frequency band based on the antenna port configuration. At 6330, WTRU 102 can perform reception (e.g., according to scheduling) of PDSCH transmissions with (e.g., one or more) DM-RSs for PDSCH transmission. At 6330, WTRU 102 can receive one or more DM-RSs for PDSCH transmission at the determined multiple DM-RS locations. At 6340, WTRU 102 can use the one or more DM-RSs received at the determined multiple DM-RS locations to perform decoding of the PDSCH transmission.

[0426] Figure 64 This is an exemplary process that can be implemented by a RAN entity for transmitting PDSCH transmissions using higher-density DM-RS. For example... Figure 64 As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 6400 to transmit PDSCH transmissions. Process 6400 can begin at 6410 with the RAN entity transmitting information indicating antenna port configuration. Subsequently, at 6420, the RAN entity can continue transmitting (e.g., according to a schedule) PDSCH transmissions with (e.g., one or more) DM-RSs for PDSCH transmissions. The RAN entity can transmit one or more DM-RSs for PDSCH transmissions at multiple DM-RS locations corresponding to consecutive resource elements on the frequency, based on the antenna port configuration.

[0427] Figure 65 This is an exemplary process that can be implemented by WTRU 102 to send PUSCH transmissions using a higher density DM-RS. For example... Figure 65 As shown, WTRU 102 can implement process 6500 to receive PUSCH transmissions. Process 6500 can begin at 6510 with WTRU 102 receiving information indicating antenna port configuration. Then, at 6520, WTRU 102 can continue to determine multiple DM-RS locations corresponding to consecutive resource elements on the frequency based on the antenna port configuration. At 6530, WTRU 102 can perform a PUSCH transmission (e.g., according to a schedule) with (e.g., one or more) DM-RS for PUSCH transmission. At 6530, WTRU 102 can transmit one or more DM-RS for PUSCH transmission at the determined multiple DM-RS locations.

[0428] Figure 66This is an exemplary process that can be implemented by a RAN entity for receiving PDSCH transmissions using higher-density DM-RS. For example... Figure 66 As shown, a RAN entity (e.g., gNB 180 or a similar entity) can implement process 6600 to receive PDSCH transmissions. Process 6600 can begin at 6610 with the RAN entity sending information indicating antenna port configuration. Then, at 6620, the RAN entity can continue to receive (e.g., according to scheduling) PUSCH transmissions with (e.g., one or more) DM-RSs for PUSCH transmissions. At 6620, the RAN entity can receive one or more DM-RSs for PUSCH transmissions at multiple DM-RS locations corresponding to consecutive resource elements on the frequency, based on the antenna port configuration. At 6630, the RAN entity can use the one or more DM-RSs received at the determined multiple DM-RS locations to perform decoding of the PUSCH transmissions.

[0429] In some representative implementations, the antenna port configuration can be based on, for example... Figure 23 The antenna port indication table shown is used to configure higher-density DM-RS. For example, antenna port configuration can be used (e.g., by a WTRU) to receive PDSCH with higher-density DM-RS and / or (e.g., by a WTRU) to transmit RRC-based messages and DCI indications for PUSCH with higher-density DM-RS. For example, REs for other DM-RS ports can be used for scheduled DM-RS ports, for example, to achieve better channel estimation performance in the frequency domain with higher-density DM-RS as described herein.

[0430] like Figure 24 As illustrated in the example, multiple (e.g., two) CDM mappings (e.g., pattern #1 and pattern #2) can be provided for higher DM-RS densities of single-symbol type 1DM-RS. Pattern #1 can support CDM between consecutive REs in the frequency domain (e.g., as well as single-symbol type 1DM-RS). For example, pattern #1 can be more easily implemented if it assigns codes with adjacent REs and / or does not require the use of memory. For example, pattern #1 may not support coexistence between single-symbol type 1DM-RS ports and single-symbol higher density DM-RS ports because the CDM sequences of single-symbol type 1DM-RS ports and single-symbol higher density DM-RS ports may not be orthogonal.

[0431] Pattern #1 supports CDM with continuous REs. Pattern #2 supports CDM based on a comb (e.g., a comb pattern) with one RE interval. Pattern #1 may not support orthogonal multiplexing between a single-symbol type 1 DM-RS port and a single-symbol high-density DM-RS port. Pattern #2 supports orthogonal multiplexing between DM-RS ports and single-symbol high-density DM-RS ports. Other example patterns for higher-density DM-RS are described in this document.

[0432] like Figure 25 As illustrated in the example, multiple (e.g., two) sequence mappings (e.g., sequence mapping #1 and sequence mapping #2) can be provided for higher DM-RS densities of single-symbol type 1 DM-RS. Sequence mapping #1 can map sequences sequentially. Sequence mapping #1 is easier to implement and may not require the use of memory. For example, if the pseudo-random (PN) sequence mapping is not designed for low correlation, sequence mapping #1 can provide higher correlation between single-symbol type 1 DM-RS ports and single-symbol higher density DM-RS.

[0433] like Figure 25 As shown in the example, multiple (e.g., two) sequence maps (e.g., sequence map #1 and sequence map #2) can be provided for higher DM-RS densities of single-symbol type 1 DM-RS. Sequence map #1 can map sequences sequentially. Sequence map #1 is easier to implement and can be implemented without the need for memory. Sequence map #2 can provide simultaneous use of existing DM-RS and higher density DM-RS. For example, as... Figure 25 As shown, sequence mapping #1 has high correlation with existing DM-RS because pseudo-noise (PN) sequences with different sequence lengths partially overlap. However, sequence mapping #2 provides low correlation because PN sequences with the same sequence length are designed to completely overlap.

[0434] As described in this article, Figure 26 , Figure 27 , Figure 28 , Figure 29 , Figure 30 , Figure 31 and Figure 32 Further examples of higher-density DM-RS and sequence mapping for higher-density DM-RS are also shown. (See also...) Figures 24 to 32 As seen in the example shown, higher density DM-RS can be achieved by arranging DM-RS in consecutive REs in the frequency domain. For example, Figures 29 to 32 This arrangement can be applied to both single-symbol and double-symbol DM-RS. Depending on the sequence mapping type, sequential sequence mapping or sequence mapping based on existing DM-RS positions can be implemented.

[0435] Figure 67This is an exemplary process that can be implemented by WTRU 102 for decoding PDDCH transmissions with DM-RS using frequency hopping or density variations. For example... Figure 67 As shown, WTRU 102 can implement process 6700 to decode PDDCH transmissions with DM-RS using frequency hopping or density variations. Process 6700 may begin at 6710, where WTRU 102 receives (e.g., from gNB 180 or a similar entity) information indicating the CORESET configuration. The CORESET configuration may include an indication of symbol duration and / or an indication of PDDCH DM-RS frequency hopping or density variations. Reception at 4710 and / or 4720 may be performed, for example, according to the techniques described herein. At 6720, WTRU 102 may continue to determine multiple DM-RS locations in one or more REGs of the CORESET. After 6720, at 6730, WTRU 102 may receive PDDCH transmissions in the search space associated with the CORESET, where one or more PDDCH DM-RSs are in the determined multiple DM-RS locations in one or more REGs. At 6740, WTRU 102 uses one or more PDCCH DM-RSs from the determined DM-RS locations to perform decoding of the received PDCCH transmission. After 6740, at 6750, WTRU 102 may continue to receive PDSCH transmissions or send PUSCH transmissions based on one or more DCI fields of the decoded PDCCH transmission.

[0436] Figure 68 This is an exemplary process that can be implemented by a RAN entity for transmitting PDDCH transmissions with DM-RS using frequency hopping or density variations. For example... Figure 68 As shown, a RAN entity (e.g., gNB 180 or a similar entity) may implement process 6800 for transmitting PDDCH transmissions with DM-RS using frequency hopping or density variations. Process 6800 may begin at 6810, where the RAN entity transmits (e.g., to WTRU) information indicating the CORESET configuration. The CORESET configuration may include an indication of symbol duration and / or an indication of PDDCH DM-RS frequency hopping or density variations. At 6820, the RAN entity may transmit PDDCH transmissions in the search space associated with the CORESET, where one or more PDDCH DM-RSs for the PDDCH transmissions are located in multiple DM-RS locations associated with the CORESET configuration. For example, the RAN entity may receive PUSCH transmissions or send PDDCH transmissions to WTRU 102 after step 6820 based on the DCI (e.g., scheduled by the DCI) of the PDDCH transmissions at 6820.

[0437] In some representative implementations, multiple DM-RS locations for the PDCCH DM-RS (e.g., in one or more REGs of the CORESET) may be determined based on: (1) any of the indications (e.g., frequency hopping or density variation), symbol duration, DCI format, and / or aggregation level; and (2) the corresponding REG index for each REG in the one or more REGs. For example, Figure 6 Example 600 of PDCCH 606 ​​is shown, and Figure 10 Example 1000 of CORESET 1002, REG 1004 and RE1008 are shown.

[0438] In some representative implementations, multiple DM-RS locations may be located in at least the first REG that has the lowest corresponding REG index in the CORESET's (e.g., one or more) REGs. For example, Figure 41 and Figure 43 Frequency hopping of the PDCCH DM-RS4102 and examples of frequency hopping of the PDCCH DM-RS 4102 are shown 4100-4300. For example, in Figure 41 In this context, PDCCH DM-RS 4102 of REG 1 can be 1 RE away from PDCCH DM-RS 4102 of REG 0. PDCCH DM-RS 4102 of REG 2 can be 2 RE away from PDCCH DM-RS 4102 of REG 0 (e.g., and 1 RE away from PDCCH DM-RS of REG 1). For example, in... Figure 43 In this context, REGs with even-numbered REG indices may have enhanced PDCCH DM-RS 4102, while REGs with odd-numbered REG indices may not have PDCCH DM-RS (e.g., no PDCCH DM-RS is located in an RE associated with an odd-numbered REG index). For example, lower PDCCH DM-RS density may be supported instead of skipping PDCCH DM-RS transmissions. One or more representative criteria and / or conditions described herein may be used to determine the location of PDCCH DM-RS.

[0439] Although the features and elements described above are described in specific combinations, each feature or element may be used alone without other features and elements of the corresponding implementation, or in various combinations with or without other features and elements.

[0440] While the specific implementations described herein may take into account 3GPP-specific protocols, it should be understood that the specific implementations described herein are not limited to this scenario and are applicable to other wireless systems. For example, although the solutions described herein take into account LTE, LTE-A, New Radio (NR), or 5G-specific protocols, it should be understood that the solutions described herein are not limited to this scenario and are also applicable to other wireless systems.

[0441] Systems and methods for processing data according to representative embodiments can be executed by one or more processors that execute sequences of instructions contained in a memory device. Such instructions can be read into the memory device from other computer-readable media, such as auxiliary data storage devices. Execution of the sequence of instructions contained in the memory device causes the processor to operate, for example, as described above. In alternative embodiments, hardwired circuitry may be used instead of software instructions, or hardwired circuitry may be combined with software instructions to implement the invention. Such software can run remotely on a processor housed within a vehicle and / or another mobile device. In the latter case, data can be transferred between vehicles or other mobile devices via wired or wireless means.

[0442] Although features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as internal hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile optical discs (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

[0443] Furthermore, the above embodiments specify processing platforms, computing systems, controllers, and other devices including processors. These devices may include at least one central processing unit (“CPU”) and memory. According to the practice of those skilled in the art of computer programming, references to symbolic representations of actions and operations or instructions can be executed by various CPUs and memories. Such actions and operations or instructions can be considered as being “executed,” “computer-executed,” or “CPU-executed.”

[0444] Those skilled in the art will recognize that the actions and symbols representing operations or instructions include the CPU's manipulation of electrical signals. The electrical system represents data bits, which can lead to the final transformation or reduction of electrical signals and the retention of data bits at memory locations in the memory system, thereby reconfiguring or otherwise altering the CPU's operation and performing other signal processing. The memory location holding the data bits is a physical location having specific electrical, magnetic, optical, or organic properties corresponding to or representing the data bits. It should be understood that representative embodiments are not limited to the platforms or CPUs described above, and other platforms and CPUs may also support the provided methods.

[0445] Data bits may also be stored on a computer-readable medium, including disks, optical disks, and any other CPU-readable volatile (e.g., random access memory (“RAM”)) or non-volatile (e.g., read-only memory (“ROM”)) mass storage system. The computer-readable medium may include cooperative or interconnected computer-readable media that are uniquely present on the processing system or distributed across multiple interconnected processing systems, which may be local or remote relative to the processing system. It should be understood that representative embodiments are not limited to the memory described above, and other platforms and memories may also support the methods described. It should be understood that representative embodiments are not limited to the platform or CPU described above, and other platforms and CPUs may also support the provided methods.

[0446] In exemplary embodiments, any of the operations, processes, etc., described herein may be implemented as computer-readable instructions stored on a computer-readable medium. These computer-readable instructions may be executed by a processor of a mobile unit, network element, and / or any other computing device.

[0447] There is little difference between the hardware and software implementations of various aspects of the system. The use of hardware or software typically (but not always, as the choice between hardware and software can become important in certain contexts) represents a design choice that weighs cost against efficiency. Various media (e.g., hardware, software, and / or firmware) may exist to implement the processes and / or systems and / or other technologies described herein, and the preferred media may vary depending on the context of deployment. For example, if the implementer determines that speed and accuracy are most important, the implementer may choose a media that is primarily hardware and / or firmware. If flexibility is most important, the implementer may choose a primarily software implementation. Alternatively, the implementer may choose some combination of hardware, software, and / or firmware.

[0448] The above detailed description has illustrated various embodiments of the apparatus and / or process using block diagrams, flowcharts, and / or examples. Where such block diagrams, flowcharts, and / or examples contain one or more functions and / or operations, those skilled in the art will understand that each function and / or operation within such block diagrams, flowcharts, or examples can be implemented individually and / or collectively by a wide range of hardware, software, firmware, or virtually any combination thereof. Suitable processors include (by way of example) general-purpose processors, special-purpose processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), field-programmable gate array (FPGA) circuits, any other type of integrated circuit (IC) and / or state machine.

[0449] Although features and elements have been provided above in specific combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with other features and elements. This disclosure is not limited to the specific embodiments described in this patent application, which are intended as examples of various aspects. Many modifications and variations are possible without departing from the spirit and scope of the invention, as will be apparent to those skilled in the art. Unless expressly stated otherwise, no element, action, or description used in this specification should be construed as essential or necessary to the invention. Based on the foregoing description, functionally equivalent methods and apparatus within the scope of this disclosure, other than those listed herein, will be apparent to those skilled in the art. Such modifications and variations are intended to fall within the scope of the appended claims. This disclosure is limited only to the terms of the appended claims and the full scope of equivalents of such claimed claims. It should be understood that this disclosure is not limited to any particular method or system.

[0450] It should also be understood that the terminology used herein is for the purpose of describing specific implementations only and is not intended to be limiting. As used herein, when referred to herein, the term “station” and its abbreviation “STA”, “user equipment” and its abbreviation “UE” may mean: (i) a wireless transmitting and / or receiving unit (WTRU), as described below; (ii) any of several implementations of a WTRU, as described below; (iii) equipment having wireless and / or wired (e.g., tetherable) capabilities configured with some or all of the structure and functions of a WTRU, as described below; (iii) equipment having wireless and / or wired capabilities configured with fewer than all the structure and functions of a WTRU, as described below; or (iv) etc. The following is relative to Figures 1A to 1DDetails of an exemplary WTRU that can represent any UE described herein are provided.

[0451] In some representative embodiments, portions of the subject matter described herein may be implemented via application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integration formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein are, wholly or partially, equivalently implemented in an integrated circuit as one or more computer programs running on one or more computers (e.g., one or more programs running on one or more computer systems), one or more programs running on one or more processors (e.g., one or more programs running on one or more microprocessors), firmware, or virtually any combination thereof, and that designing circuitry and / or writing software and / or firmware code according to this disclosure will be entirely within the skill of those skilled in the art. Furthermore, those skilled in the art will understand that the mechanisms of the subject matter described herein can be distributed as program products in various forms, and the exemplary embodiments of the subject matter described herein apply regardless of the specific type of signal-bearing medium used to actually implement that distribution. Examples of signal-bearing media include, but are not limited to, the following: recordable media (such as floppy disks, hard disks, CDs, DVDs, digital magnetic tapes, computer memory, etc.); and transmission media (such as digital and / or analog communication media (e.g., fiber optic cables, waveguides, wired communication links, wireless communication links, etc.)).

[0452] The topics described herein sometimes illustrate different components contained within or connected to different other components. It should be understood that such depicted architectures are merely examples, and many other architectures can in fact achieve the same functionality. Conceptually, any arrangement of components achieving the same function is effectively “associated” to enable the desired functionality. Therefore, any two components combined herein to achieve a particular function can be considered “associated” with each other to enable the desired functionality, regardless of the architecture or intermediate components. Similarly, any two such associated components can also be considered “operably connected” or “operably coupled” to each other to achieve the desired functionality, and any two components that can be suchly associated can also be considered “operably coupled” to each other to achieve the desired functionality. Specific examples of operably coupled components include, but are not limited to, components that can physically cooperate and / or physically interact and / or components that can wirelessly interact and / or logically interact and / or logically interact.

[0453] Regarding virtually any plural and / or singular terms used herein, those skilled in the art can appropriately convert them from plural to singular and / or from singular to plural depending on the context and / or application. For clarity, various singular / plural permutations may be explicitly listed herein.

[0454] Those skilled in the art will understand that, in general, the terminology used herein, particularly in the appended claims (e.g., the body of the appended claims), is typically intended as “open-ended” terms (e.g., the term “comprising” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “including” should be interpreted as “including but not limited to,” etc.). Those skilled in the art will also understand that if it is intended to specify a particular number of introduced claim objects, such intention will be explicitly stated in the claims, and if no such claim objects are present, such intention will not exist. For example, the term “single” or similar language may be used where only one item is anticipated. To aid understanding, the appended claims and / or the description herein may contain the use of the introductory phrases “at least one” and “one or more” to introduce claim objects. However, the use of such phrases should not be construed as implying that any particular claim containing such introduced claim objects is limited to an embodiment containing only one such claim object by using the indefinite articles “a” or “an.” This is true even when the same claim includes the introductory phrase "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and / or "an" should be interpreted as meaning "at least one" or "one or more"). The same applies to the use of definite articles used to introduce the subject matter of a claim. Furthermore, even when a specific number of the introduced subject matter of a claim is explicitly stated, those skilled in the art will recognize that such a statement should be interpreted as meaning at least the stated number (e.g., a bare statement of "two subject matters" without other modifiers means at least two subject matters, or two or more subject matters). Additionally, in instances where conventions such as "at least one of A, B, and C" are used, generally speaking, such constructions mean that those skilled in the art will understand that convention (e.g., "a system having at least one of A, B, and C" will include, but is not limited to, systems having A alone, having B alone, having C alone, having both A and B, having both A and C, having both B and C, and / or having both A, B, and C, etc.). In instances where conventions such as "at least one of A, B, or C" are used, generally speaking, such a construction implies that a person skilled in the art will understand that the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A alone, having B alone, having C alone, having both A and B, having both A and C, having both B and C, and / or having both A, B, and C, etc.). A person skilled in the art should also understand that, in fact, any separate words and / or phrases presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibility of including one term, any one of the terms, or both terms.For example, the phrase “A or B” will be understood to include the possibility of “A” or “B” or “A and B”. Additionally, as used herein, the term “any one of…” followed by a list of multiple items and / or multiple item categories is intended to include items alone or in combination with other items and / or other item categories, “any one of,” “any combination,” “any multiple,” and / or “any combination of multiples of.” Furthermore, as used herein, the term “group” or “cluster” is intended to include any number of items, including zero. Additionally, as used herein, the term “quantity” is intended to include any quantity, including zero.

[0455] Furthermore, where features or aspects of this disclosure are described in accordance with the Markush Group, those skilled in the art will recognize that this disclosure is also described in accordance with any individual member of the Markush Group or a subgroup of its members.

[0456] As those skilled in the art will understand, for any and all purposes (such as for providing a written description), all scopes disclosed herein also encompass any and all possible subscopes and combinations thereof. Any listed scope can be readily identified as sufficiently descriptive and such that the same scope can be divided into at least two equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each scope discussed herein can be readily divided into a lower third, a middle third, and an upper third, etc. As those skilled in the art will also understand, all language such as “at most,” “at least,” “greater than,” “less than,” etc., includes the referenced number and refers to a scope that can subsequently be divided into subscopes as described above. Finally, as those skilled in the art will understand, a scope includes each individual number. Thus, for example, a group having 1 to 3 units means a group having 1, 2, or 3 units. Similarly, a group having 1 to 5 units means a group having 1, 2, 3, 4, or 5 units, etc.

[0457] Furthermore, unless otherwise stated, the claims should not be construed as being limited to the order or elements provided. Additionally, the use of the term "means for..." in any claim is intended to invoke 35 U.S.SC §112. 6. The claim format is either device plus function, and any claim without the term "device for..." is not intended to be so.

[0458] The software-associated processor can be used to implement the radio frequency transceiver in a Transmitter-Receiver Unit (WTRU), User Equipment (UE), terminal, base station, Mobility Management Entity (MME), or Evolved Packet Core (EPC), or any host. The WTRU can be used in conjunction with modules and can be implemented in hardware and / or software including: Software-defined Radio (SDR) and other components such as cameras, video camera modules, videophones, speakerphones, vibration devices, speakers, microphones, television transceivers, hands-free headsets, keypads, etc. Modules, FM radio units, Near Field Communication (NFC) modules, Liquid Crystal Display (LCD) units, Organic Light Emitting Diode (OLED) units, Digital Music Players, Media Players, Video Game Players, Internet Browsers, and / or any Wireless Local Area Network (WLAN) or Ultra-Wideband (UWB) modules.

[0459] Throughout the disclosed content, those skilled in the art should understand that certain representative implementations may be used in alternative forms or in combination with other representative implementations.

[0460] Furthermore, the methods described herein can be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as internal hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile optical discs (DVDs)). The processor associated with the software can be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method implemented by a Wireless Transmit / Receive Unit (WTRU), the method comprising: Receive information indicating the configuration of the control resource set CORESET, the CORESET configuration including an indication of symbol duration and an indication of frequency hopping or density change of the physical downlink control channel PDCCH demodulation reference signal DM-RS; The multiple DM-RS locations in one or more resource element groups (REGs) of the CORESET are determined based on the following: (1) the indication of symbol duration and the indication of PDCCH DMRS frequency hopping or density change; and (2) the corresponding index of the one or more REGs; Receive PDCCH transmissions in the search space associated with the CORESET, wherein one or more PDCCH DM-RS are located in the plurality of DM-RS positions in one or more REGs; The received PDCCH transmission is decoded using one or more PDCCH DM-RS at the plurality of DM-RS locations; as well as Communication is based on one or more downlink control information (DCI) fields transmitted via the decoded PDCCH.

2. The method of claim 1, wherein the determination of the plurality of DM-RS locations in one or more REGs of the CORESET is further based on either (3) the DCI format and / or (4) the aggregation level.

3. The method of claim 1, wherein the plurality of DM-RS locations are in at least the first REG with the lowest index in the one or more REGs of the CORESET.

4. The method of claim 1, wherein the determination of the plurality of DM-RS positions in the one or more REGs of the CORESET is based on the indication of PDCCH DM-RS frequency hopping and the corresponding index of each REG in the one or more REGs, and the plurality of DM-RS positions have different frequency positions in each REG in the one or more REGs.

5. The method of claim 1, wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are different in different REGs of the one or more REGs of the CORESET.

6. The method of claim 5, wherein the plurality of DM-RS locations in adjacent REGs of one or more REGs are in resource elements that are frequency-continuous.

7. The method of claim 1, wherein the determination of the plurality of DM-RS locations in the one or more REGs of CORESET is based on the indication of PDCCH DM-RS density variation and the corresponding index of each REG in the one or more REGs, and the plurality of DM-RS locations are in only one REG in the one or more REGs.

8. A wireless transmit / receive unit (WTRU), the WTRU comprising: A processor and a transceiver, wherein the processor and the transceiver are configured to: Receive information indicating the configuration of the CORESET control resource set, which includes an indication of symbol duration and an indication of frequency hopping or density changes in the Physical Downlink Control Channel (PDCCH) demodulation reference signal (DM-RS). The multiple DM-RS locations in one or more resource element groups (REGs) of the CORESET are determined based on: (1) the indication of symbol duration and the indication of PDCCH DMRS frequency hopping or density change; and (2) the corresponding index of the one or more REGs. Receive PDCCH transmissions in the search space associated with the CORESET, wherein one or more PDCCH DM-RS are located in the plurality of DM-RS positions in one or more REGs. The received PDCCH transmission is decoded using one or more PDCCH DM-RS locations from the plurality of DM-RS locations, and Communication is based on one or more downlink control information (DCI) fields transmitted via the decoded PDCCH.

9. The WTRU of claim 8, wherein the processor is configured to further determine the plurality of DM-RS locations in one or more REGs of the CORESET based on either (3) the DCI format and / or (4) the aggregation level.

10. The WTRU of claim 8, wherein the plurality of DM-RS locations are in at least the first REG with the lowest index in the one or more REGs of the CORESET.

11. The WTRU of claim 8, wherein the processor is configured to determine the plurality of DM-RS positions in the one or more REGs of the CORESET based on the indication of PDCCH DM-RS frequency hopping and the corresponding index of each REG in the one or more REGs, and the plurality of DM-RS positions have different frequency positions in each REG in the one or more REGs.

12. The WTRU of claim 8, wherein the plurality of DM-RS positions in the one or more REGs of the CORESET are different in different REGs of the one or more REGs of the CORESET.

13. The WTRU of claim 8, wherein the plurality of DM-RS locations in adjacent REGs of one or more REGs are in resource elements that are frequency-continuous.

14. The WTRU of claim 8, wherein the determination of the plurality of DM-RS locations in the one or more REGs of the CORESET is based on the indication of PDCCH DM-RS density variation and the corresponding REG index of each of the one or more REGs, and the plurality of DM-RS locations are in only one of the one or more REGs.

15. The WTRU of claim 8, wherein the plurality of DM-RS locations in one or more REGs of the CORESET are located in fewer than all REGs of the CORESET.

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