Enhancement of DMRS

Abstract

The WTRU may receive DCI including information for scheduling transmissions and associating DMRS ports with CDM groups. The WTRU may associate a first DMRS port with a first CDM group and a second DMRS port with a second CDM group based on the DCI. The WTRU may map the first DMRS port associated with the first CDM group to a first antenna group and map the second DMRS port associated with the second CDM group to a second antenna group. The WTRU may transmit at least a first DMRS using the first DMRS port and the first antenna group and transmit at least a second DMRS using the second DMRS port and the second antenna group. The WTRU may select a first DMRS port based on the MCS, associate a first PTRS port with the first DMRS port, and transmit PTRS using the PTRS port.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 335,504, filed Apr. 27, 2022; U.S. Provisional Patent Application No. 63 / 395,457, filed Aug. 5, 2022; U.S. Provisional Patent Application No. 63 / 411,355, filed Sep. 29, 2022; U.S. Provisional Patent Application No. 63 / 422,069, filed Nov. 3, 2022; and U.S. Provisional Patent Application No. 63 / 445,342, filed Feb. 14, 2023, the entire disclosures of all of which are hereby incorporated by reference in their entirety.

Background Art

[0002] Mobile communications using wireless communication are continuously evolving. The fifth generation may be referred to as 5G. Previous (conventional) generations of mobile communications can be, for example, the fourth generation (4G) long term evolution (LTE).

Summary of the Invention

[0003] This specification describes systems, methods, and means for enhancing DMRS.

[0004] A wireless transmit and receive unit (WTRU) may be configured to map a code division multiplexing (CDM) group to a demodulation reference signal (DMRS) port. The WTRU may send information associated with at least one of the WTRU's coherence capabilities or antenna layout to a base station. This information may include, for example, information identifying one or more coherent antenna groups. This information may indicate the number of coherent antenna groups included in the WTRU, for example, one, two, etc.

[0005] For example, a base station that may be a gNode B may receive information associated with at least one coherence capability or antenna layout of a WTRU. The base station may schedule transmissions and determine information associating DMRS ports with CDM groups based on the information associated with at least one coherence capability or antenna layout. The base station may, for example, schedule a transmission that may be a PUSCH transmission and send information associating DMRS ports with CDM groups to the WTRU. This information may be formatted as downlink control information (DCI).

[0006] The WTRU may receive DCI from the base station. The DCI may include information scheduling transmissions and associating DMRS ports with CDM groups. The received information scheduling transmissions and associating DMRS ports with CDM groups may be based on previously sent information identifying one or more coherent antenna groups.

[0007] The WTRU may determine a first one or more DMRS ports and a second one or more DMRS ports. The WTRU may associate the first one or more DMRS ports with a first CDM group and the second one or more DMRS ports with a second CDM group based on the DCI. The WTRU may map the first one or more DMRS ports associated with the first CDM group to a first antenna group and the second one or more DMRS ports associated with the second CDM group to a second antenna group.

[0008] The WTRU may send a scheduled transmission including at least a first DMRS sent using the first one or more DMRS ports and the first antenna group and at least a second DMRS sent using the second one or more DMRS ports and the second antenna group, for example.

[0009] The WTRU may be configured to associate a phase tracking radio signal (PTRS) port with a DMRS port. The DCI received at the WTRU may specify a first PTRS port. The WTRU may determine a first DMRS port from a first one or more DMRS ports or a second one or more DMRS ports based on a modulation and coding scheme (MCS) value. The WTRU may determine the first DMRS port based on the MCS value associated with the first DMRS port being the highest MCS value associated with either the first one or more DMRS ports or the second one or more DMRS ports. The WTRU may select the first DMRS port based on, for example, the MCS associated with the first DMRS port indicating that the first DMRS port is associated with a strong link, e.g., the strongest link, for uplink transmission. The WTRU may associate the first PTRS port with the first DMRS port mapped to a first antenna group. The transmission sent by the WTRU may include a PTRS sent using the PTRS port.

[0010] The DCI received at the WTRU may specify a plurality of ports including, for example, a first PTRS port and a second PTRS port. The WTRU may associate the first PTRS port with the first DMRS port mapped to a first antenna group and may associate the second PTRS port with the second DMRS port mapped to a second antenna group. The transmission sent by the WTRU may include a first PTRS sent using the first PTRS port and a second PTRS sent using the second PTRS port. The transmission may further include a physical uplink shared channel (PUSCH) transmission.

[0011] Enhancement of the DMRS may include improvement of cross-panel DMRS interference management. The WTRU may be configured to determine a first antenna panel and a second antenna panel. The WTRU may receive a DCI including a plurality of fields associated with the antenna panel and determine the first antenna panel and the second antenna panel based on the DCI. The DCI may further include an instruction for simultaneous transmission using the first antenna panel and the second antenna panel. The WTRU may transmit to a first TRP using the first antenna panel and a first resource, and at the same time, transmit to a second TRP using the second antenna panel and the first resource.

[0012] The WTRU may be configured to determine that the first antenna panel is orthogonal to the second antenna panel. The WTRU may determine that the first antenna panel is orthogonal to the second antenna panel based on the timing advance. The WTRU may determine to transmit simultaneously from the first antenna panel and the second antenna panel based on the first antenna panel being orthogonal to the second antenna panel. The WTRU may determine that a third antenna panel is not orthogonal to the first antenna panel. The WTRU may determine to perform rate matching around the PUSCH resource of the third antenna panel.

[0013] The WTRU may be configured to determine a plurality of DMRS ports. The WTRU may determine a first group of DMRS ports and a second group of DMRS ports within the plurality of DMRS ports. The WTRU may associate the first group of DMRS ports with a first scheduled slot and associate the second group of DMRS ports with a second scheduled slot.

[0014] The WTRU may receive an indication that the position of the DMRS resource element is varied between PUSCH transmission instances. The WTRU may receive DCI and may determine a DMRS port for transmission based on the DCI. The WTRU may determine a DMRS port for transmission based at least on the uplink antenna port code within the DCI.

[0015] The enhancement of the DMRS may include the enhancement of the OCC mapping. The WTRU may be configured to determine a first group of OCCs spanning a first set of resource elements and to determine a second group of OCCs spanning a second set of resource elements. The WTRU may determine that at least one resource element is included in the first set of resource elements and the second set of resource elements. The WTRU may determine that for at least one resource element, the cover code factor for the transmission port associated with the first group of OCCs is the same as the cover code factor associated with the second group of OCCs. For the same transmission port, the cover code factors used by different OCC groups on the shared resource element may be the same. The transmission port may be a DMRS port.

[0016] Enhancement of the DMRS may include increasing the number of DMRS ports. Increasing the number of DMRS ports may be related to, for example, a new DMRS mapping pattern for SU / MU MIMO. The WTRU may be configured to receive information indicating a configuration for the DMRS. The WTRU may determine a pattern for DMRS transmission based on the configuration for the DMRS. The WTRU may determine the number of resource elements for an OFDM symbol based on the pattern for DMRS transmission. The WTRU may then determine to apply a certain OCC length to the DMRS transmission based on the configuration for the DMRS, and may send the DMRS transmission using the pattern for DMRS transmission. If the pattern for DMRS transmission is the first or second pattern, the WTRU may reduce the number of resource elements for the OFDM symbol to 2 resource elements, and may apply an OCC length of 2 or 4 to the DMRS transmission depending on the DMRS configuration. If the pattern for DMRS transmission is the third or fourth pattern, the WTRU may reduce the number of resource elements for the OFDM symbol to 1 resource element, and may apply an OCC length of 4 or 8 to the DMRS transmission depending on the DMRS configuration.

[0017] The WTRU may be configured to provide enhanced CDM grouping. The WTRU may determine a first plurality of DMRS ports and associate the first plurality of DMRS ports with a first CDM group. The WTRU may determine a second plurality of DMRS ports and associate the second plurality of DMRS ports with a second CDM group. The WTRU may communicate information using the first plurality of DMRS ports and using the second plurality of DMRS ports. One or more of the first plurality of DMRS ports and one or more of the second plurality of DMRS ports may be associated with the first CDM group. Resources associated with the first CDM group may be mutually exclusive with respect to resources associated with the second CDM group. The WTRU may determine one or more PTRS ports and may be further configured to associate the one or more PTRS ports with the first plurality of DMRS ports based on characteristics of the first plurality of DMRS ports.

[0018] The WTRU may be configured to provide enhanced DMRS mapping. The WTRU may be configured to determine an FD-OCC length associated with the FD-OCC. The WTRU may determine that the FD-OCC length is associated with one or more orphan resource elements. If the WTRU determines that the FD-OCC length is associated with one or more orphan resource elements, the WTRU may determine to shift the FD-OCC to align with the scheduled transmission. The WTRU may determine to shift the FD-OCC to align with the scheduled transmission based on a dynamic indication to shift the OCC mapping for the scheduled transmission. The dynamic indication may be received as part of the scheduling DCI. The WTRU may determine to shift the FD-OCC to align with the scheduled transmission based on the index of the reference PRB of the scheduled transmission. The WTRU may determine to shift the FD-OCC to align with the scheduled transmission based on the indicated set of antenna ports. The first group of antenna ports may be associated with the first OCC mapping, and the second group of antenna ports may be associated with the second OCC mapping.

[0019] The WTRU may be configured to provide an enhanced PTRS configuration. The WTRU may determine a plurality of antenna groups, each of the plurality of antenna groups including a plurality of antennas. The WTRU may determine one or more DMRS ports for each of the plurality of antenna groups, associate each of the plurality of antenna groups with a CDM group, and associate one or more PTRS ports with each of the one or more DMRS ports. The WTRU may associate one or more PTRS ports with each of the one or more DMRS ports by determining the number of the plurality of antenna groups and determining the number of PTRS ports based on the number of the plurality of antenna groups. The WTRU may associate one or more PTRS ports with each of the one or more DMRS ports at least partially based on DCI. The WTRU may associate one or more PTRS ports with each of the one or more DMRS ports at least partially based on DCI and MAC-CE.

Brief Description of the Drawings

[0020]

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DETAILED DESCRIPTION OF THE INVENTION

[0021] A more detailed understanding can be obtained from the following description, given by way of example in conjunction with the accompanying drawings.

[0022] FIG. 1A illustrates an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique word discrete Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filter type OFDM, filter bank multicarrier (FBMC), etc.

[0023] As shown in FIG. 1A, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any 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 subscriber units or mobile subscriber units, subscriber-based units, pagers, cellular telephones, 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, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., for remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), home appliances, devices operating in commercial wireless networks and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may also be referred to interchangeably as UEs.

[0024] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN106 / 115, the Internet 110, and / or other network 112. By way of example, base stations 114a, 114b may be a Base Transceiver Station (BTS), Node B, eNode B (eNB), Home Node B, Home eNode B, gNode B (gNB), NR Node B, a site controller, an Access Point (AP), a wireless router, etc. Although base stations 114a, 114b are each illustrated as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0025] Base station 114a may be part of RAN 104 / 113 and may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals at one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be authorized spectrum, unlicensed spectrum, or a combination of authorized and unlicensed spectrum. A cell may provide wireless service coverage to a specific geographic area that may be relatively fixed or may change 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. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0026] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 may be established using any suitable radio access technology (RAT).

[0027] More specifically, as described above, the communication system 100 can be a multiple access system, and can use one or more channel access methods such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a within RAN104 / 113, and the WTRUs 102a, 102b, 102c can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can use wideband CDMA (WCDMA) to establish the air interfaces 115 / 116 / 117. WCDMA can include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed Downlink Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0028] In one embodiment, the base station 114a and the 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 LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro) to establish the air interface 116.

[0029] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can use New Radio (NR) to establish the air interface 116.

[0030] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Accordingly, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by transmissions sent between multiple types of radio access technologies and / or multiple types of base stations (e.g., eNBs and gNBs).

[0031] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0032] The base station 114b in FIG. 1A can be, for example, a wireless router, a home node B, a home e-node B, or an access point, and can utilize any suitable RAT to facilitate wireless connection in a local area such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (e.g., for use by a drone), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0033] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, 102d. The data can have various 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, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or implement high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that employ the same or a different radio access technology (RAT) as RAN 104 / 113. For example, in addition to being connected to a RAN 104 / 113 that can utilize New Radio (NR) radio technology, CN 106 / 115 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0034] CN106 / 115 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN108 may include a circuit-switched telephone network that provides a plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, where these networks and devices use a common communication protocol such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP internet protocol suite. The network 112 may include a wired communication network and / or a wireless communication network that is owned and / or operated by another service provider. For example, the network 112 may include another CN connected to one or more RANs that may use the same RAT or a different RAT as the RAN104 / 113.

[0035] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include a multi-mode function (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in Figure 1A may be configured to communicate with a base station 114a that may employ a cellular-based wireless technology and a base station 114b that may employ IEEE802 wireless technology.

[0036] Figure 1B is a system diagram illustrating an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 can include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that the WTRU 102 can include any partial combination of the foregoing elements while remaining consistent with one embodiment.

[0037] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), a plurality of 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. The processor 118 can perform signal coding, data processing, power control, input / output processing, and / or any other function that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120 that can be coupled to a transmit / receive element 122. Although Figure 1B illustrates the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0038] The transmit / receive element 122 may be configured to transmit or receive signals to / from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0039] Although the transmit / receive element 122 is depicted in FIG. 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0040] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have a multimode function. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs such as, for example, NR and IEEE 802.11.

[0041] The processor 118 of the WTRU 102 may be coupled to the speaker / microphone 124, keypad 126, and / or display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit), and may receive data input by the user from these. The processor 118 may also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. In addition, the processor 118 may access information from and store data in any suitable type of memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0042] The processor 118 may receive power from the power supply 134 and may be configured to distribute power to and / or control the power of other components within the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry batteries (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0043] Processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via the air interface 116 and / or may determine its location based on the timing of signals received from two or more neighboring base stations. It will be appreciated that the WTRU 102 may obtain location information by any suitable positioning method while remaining consistent with one embodiment.

[0044] Processor 118 may also be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripheral devices 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0045] WTRU102 may include a full-duplex radio in which some or all of the transmission and reception of signals associated with certain subframes (e.g., for both UL (e.g., for transmission) and downlink (e.g., for reception)) can be parallel and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference either through hardware (e.g., a choke) or through signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, WRTU102 may include a half-duplex radio for the transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either UL (e.g., for transmission) or downlink (e.g., for reception)).

[0046] Figure 1C is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 may employ E-UTRA radio technology to communicate with WTRU102a, 102b, 102c via air interface 116. RAN104 may also communicate with CN106.

[0047] RAN104 may include eNodeBs 160a, 160b, 160c, although it will be understood that RAN104 may include any number of eNodeBs while remaining consistent with one embodiment. Each of eNodeBs 160a, 160b, 160c may include one or more transceivers for communicating with WTRU102a, 102b, 102c via air interface 116. In one embodiment, eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, eNodeB 160a may transmit a wireless signal to WTRU102a and / or receive a wireless signal from WTRU102a, for example, using multiple antennas.

[0048] Each of the eNodeBs 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in the UL and / or DL, etc. As shown in Figure 1C, the eNodeBs 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0049] The CN 106 shown in Figure 1C 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 will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0050] The MME 162 can be connected to each of the eNodeBs 162a, 162b, and 162c in the RAN 104 via the S1 interface and can function as a control node. For example, the MME 162 can authenticate users of the WTRUs 102a, 102b, 102c, activate / deactivate bearers, select a specific serving gateway during the initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 can provide control plane functions for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM and / or WCDMA.

[0051] The SGW 164 can be connected to each of the eNodeBs 160a, 160b, and 160c in the RAN 104 via the S1 interface. The SGW 164 can generally route and transfer user data packets to and from the WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during eNodeB handover, triggering paging when DL data is available to the WTRUs 102a, 102b, and 102c, and managing and storing the contexts of the WTRUs 102a, 102b, and 102c.

[0052] The SGW 164 can be connected to the PGW 166, and the PGW 166 can provide the WTRUs 102a, 102b, and 102c with access to a packet switched network such as the Internet 110 to facilitate communication between the WTRUs 102a, 102b, and 102c and IP-enabled devices.

[0053] The CN 106 can facilitate communication with other networks. For example, the CN 106 can provide the WTRUs 102a, 102b, and 102c with access to a circuit switched network such as the PSTN 108 to facilitate communication between the WTRUs 102a, 102b, and 102c and conventional landline communication devices. For example, the CN 106 can include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 can provide the WTRUs 102a, 102b, and 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers.

[0054] The WTRU is described as a wireless terminal in FIGS. 1A - 1D, but in certain representative embodiments, it is contemplated that such a terminal can use a wired communication interface (e.g., temporarily or permanently) with the communication network.

[0055] In a representative embodiment, the other network 112 can be a WLAN.

[0056] A WLAN in infrastructure basic service set (BSS) mode can have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP can have access to or an interface to another type of wired / wireless network that carries traffic entering and / or exiting the distribution system (DS) or BSS. Traffic destined for an STA originating outside the BSS can reach and be delivered to the STA through the AP. Traffic originating from an STA to a destination outside the BSS can be sent to the AP to be delivered to their respective destinations. Traffic between STAs within the BSS can be sent through the AP, for example, the 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 peer-to-peer traffic. Peer-to-peer traffic can be sent between the source STA and the destination STA (e.g., directly between them) using direct link setup (DLS). In certain representative embodiments, DLS can use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) can communicate directly with each other. The IBSS mode of communication can be referred to herein as the "ad hoc" communication mode.

[0057] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may transmit beacons on a fixed channel such as the primary channel. The primary channel can be of a fixed width (e.g., a 20 MHz-wide bandwidth) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS, but can also be used by the STA to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. In the case of CSMA / CA, STAs including the AP (e.g., all STAs) can sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA can back off. Only one STA (e.g., only one station) can transmit at any given time in a given BSS.

[0058] A High Throughput (HT) STA can use a 40 MHz-wide channel for communication, and this 40 MHz-wide channel can be formed, for example, via a combination of a primary 20 MHz channel and an adjacent or non-adjacent 20 MHz channel.

[0059] A Very High Throughput (VHT) STA may support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. A 40 MHz and / or 80 MHz channel may be formed by combining a plurality of consecutive 20 MHz channels. A 160 MHz channel may be formed by combining eight consecutive 20 MHz channels, or by combining two non - consecutive 80 MHz channels, which may be referred to as an 80 + 80 configuration. In the case of the 80 + 80 configuration, after channel encoding, the data may pass through a segment parser that can divide the data into two streams. The Inverse Fast Fourier Transform (IFFT) process and time - domain processing may be performed separately for each stream. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80 + 80 configuration may be reversed, and the combined data may be transmitted to the Medium Access Control (MAC).

[0060] The sub-1 GHz operating mode is supported by 802.11af and 802.11ah. The channel operating bandwidth and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to an exemplary embodiment, 802.11ah may support meter-type control / machine-type communication, such as MTC devices within a macro communication range area. The MTC device may have limited capabilities, including certain capabilities, such as support for a certain and / or limited bandwidth (e.g., support only for these). The MTC device may include a battery having a battery life above a threshold (e.g., to maintain a very long battery life).

[0061] A WLAN system that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or restricted by an STA from among all STAs operating in a BSS that supports the minimum bandwidth operation mode. In an example of 802.11ah, the primary channel is 1 MHz wide for an STA (e.g., an MTC type device) that supports the 1 MHz mode (e.g., supports only this) even when the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or Network Allocation Vector (NAV) setting may depend on the status of the primary channel. For example, due to an STA transmitting to the AP (supporting the 1 MHz operation mode (e.g., only the 1 MHz operation mode)), if the primary channel is busy, the entire available frequency band may be considered busy even if most of the frequency band remains idle and available.

[0062] In the United States, the available frequency band that can be used by 802.11ah is 902 MHz to 928 MHz. In Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0063] FIG. 1D is a system diagram showing RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0064] RAN 113 may include gNBs 180a, 180b, 180c, but it will be understood that RAN 113 may include any number of gNBs while remaining consistent with one embodiment. Each of gNBs 180a, 180b, 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, 102c via air interface 116. In one embodiment, gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, 180c. Thus, gNB 180a may transmit and / or receive radio signals to / from WTRU 102a using, for example, multiple antennas. In one embodiment, gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In one embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0065] The WTRUs 102a, 102b, and 102c can communicate with the gNBs 180a, 180b, and 180c using transmissions associated with scalable numerology. For example, the OFDM symbol interval and / or the OFDM sub-carrier interval can vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. The WTRUs 102a, 102b, and 102c can communicate with the gNBs 180a, 180b, and 180c using sub-frames or transmission time intervals (TTIs) of various or scalable lengths (e.g., including various numbers of OFDM symbols and / or having absolute times of various lengths).

[0066] gNBs 180a, 180b, and 180c may be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNodeBs 160a, 160b, and 160c, etc.). In a stand-alone configuration, WTRUs 102a, 102b, and 102c may utilize one or more of gNBs 180a, 180b, and 180c as mobility anchor points. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using signals in an unlicensed band. In a non-stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with and connect to gNBs 180a, 180b, and 180c while also communicating with and connecting to another RAN such as eNodeBs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c may implement a DC principle for communicating with one or more gNBs 180a, 180b, and 180c and one or more eNodeBs 160a, 160b, and 160c substantially simultaneously. In a non-stand-alone configuration, eNodeBs 160a, 160b, and 160c may function as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c may provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0067] 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 decision-making, handover decision-making, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, and routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0068] As shown in FIG. 1D, CN 115 can include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and optionally data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of CN 115, it will be understood that any of these elements can be owned and / or operated by entities other than the CN operator.

[0069] AMF 182a and 182b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can function as control nodes. For example, AMF 182a and 182b can play roles such as authentication of users of WTRUs 102a, 102b, and 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selection of specific SMFs 183a and 183b, management of the registration area, termination of NAS signaling, and mobility management. Network slicing can be used by AMF 182a and 182b to customize the CN support for WTRUs 102a, 102b, and 102c based on the type of service being utilized by WTRUs 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 massive mobile broadband (eMBB) access, and services for machine type communication (MTC) access. AMF 162 can provide control plane functions for exchange between RAN 113 and other RANs (not shown) that use other radio technologies such as non-3GPP access technologies like LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0070] SMF183a and 183b can be connected to AMF182a and 182b within CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b within CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a 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. The PDU session type can be IP-based, non-IP-based, Ethernet-based, etc.

[0071] UPF184a and 184b can be connected to one or more of gNB180a, 180b, and 180c within RAN113 via the N3 interface, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-corresponding devices. UPF184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-home PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0072] CN115 may facilitate communication with other networks. For example, CN115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN115 and the PSTN 108. In addition, CN115 can provide access to other network 112 for the WTRUs 102a, 102b, 102c, and the other network 112 may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c can be connected to the local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0073] Looking at FIGS. 1A - 1D and the corresponding descriptions of FIGS. 1A - 1D, one or more of the functions described herein related to one or more of the WTRUs 102a - d, base stations 114a and b, eNodeBs 160a - c, MME 162, SGW 164, PGW 166, gNBs 180a - c, AMFs 182a and b, UPFs 184a and b, SMFs 183a and b, DNs 185a and b, and / or any other device described herein may be implemented by one or more emulation devices (not shown). An emulation device can be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functionality.

[0074] An emulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, one or more emulation 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. One or more emulation devices may perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. An emulation device can be directly coupled to another device for testing purposes and / or can perform tests using terrestrial wireless communication.

[0075] One or more emulation devices can perform one or more functions, including all, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device can be utilized in a test scenario in a test laboratory and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing) to implement tests of one or more components. One or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (which may include one or more antennas) can be used by the emulation device to transmit and / or receive data.

[0076] This application discloses enhancements to DMRS. The enhancements to DMRS may relate to, for example, increasing the number of ports, supporting simultaneous multi-panel transmission, and / or supporting 8TX WTRUs. The disclosed enhancements to DMRS may include procedures for cross-panel DMRS interference management. Cross-panel DMRS interference management may relate to, for example, solutions for cross-panel DMRS pairing and orthogonal / non-orthogonal mapping. The disclosed enhancements to DMRS may include procedures for enhanced OCC mapping. Enhanced OCC mapping may relate to using shared / duplicate OCC. The disclosed enhancements to DMRS may include procedures for increasing the number of DMRS ports. Increasing the number of DMRS ports may relate to, for example, new DMRS mapping patterns for SU / MU MIMO. The disclosed enhancements may be applicable to and used for the transmission of signals having a specific transmission pattern, such as demodulation reference signals, broadcast reference signals, etc., in, for example, the time domain, frequency domain, and code domain. For the sake of brevity, PUSCH DMRS or PDSCH DMRS may be considered as an example.

[0077] Demodulation reference signal (DMRS) configurations that define the placement of reference signals in time and frequency may be designed to address various scenarios for the purpose of maintaining high design flexibility and forward compatibility while dealing with implementation complexity and constraints from the perspective of the receiver. Since the pilot placement pattern can affect the number of orthogonal antenna ports supported for single user (SU) / multi-user (MU) MIMO (SU / MU-MIMO) transmission, it can be, for example, an essential part of the design of an efficient multiple-input and multiple-output (MIMO) communication system.

[0078] Figures 2A and 2B show examples of DMRS configuration types for a Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) waveform. A first exemplary DMRS configuration type as shown in Figure 2A may be referred to as DMRS configuration type 1. A second exemplary DMRS configuration type as shown in Figure 2B may be referred to as DMRS configuration type 2. Both exemplary configurations may support single-symbol and double-symbol DMRS mapping. To efficiently use available resources, an orthogonal cover code (OCC) may be used to support multi-port operation of DMRS. For example, in the illustrated single-symbol configuration, two antenna ports using the same resource element may be orthogonalized by using a length-2 OCC, while in the case of a double-symbol configuration, four antenna ports may be orthogonalized by using a length-4 OCC.

[0079] The DMRS configuration type can specify the density of DMRS in the frequency domain and can determine the number of orthogonal antenna ports, e.g., the maximum number, supported per physical resource block. The difference between configuration types can be that DMRS configuration type 1 may have a higher density of pilot frequency domain occupancy compared to DMRS configuration type 2, which can make DMRS configuration type 1 more resilient to frequency domain channel variations. On the other hand, DMRS configuration type 2 may have more orthogonal antenna ports (although there may be a trade-off of reduced DMRS density). Thus, DMRS configuration type 1 can support a maximum of 4 orthogonal ports for a single-symbol configuration and a maximum of 8 orthogonal ports for a double-symbol configuration. DMRS configuration type 2 can support a maximum of 6 orthogonal ports for a single-symbol configuration and a maximum of 12 orthogonal ports for a double-symbol configuration, which can make DMRS configuration type 2 more suitable for MU-MIMO.

[0080] In relation to MIMO, enhancements for uplink transmission may be considered for certain categories of WTRUs to enhance coverage, reliability, and throughput. Enhancements to DMRS may be employed to support the following features.

[0081] The first feature may be to specify a larger number of orthogonal DMRS ports for downlink and uplink MU-MIMO (e.g., increasing or not increasing the DM-RS overhead) for CP-OFDM only, for example. This feature may require a common design between DL and UL DMRS. This feature can employ, for example, up to 24 orthogonal DM-RS ports, and for each applicable DMRS type, the maximum number of orthogonal ports can be doubled for both single-symbol DMRS and double-symbol DMRS.

[0082] The second feature may be to specify enhancements to UL DMRS, SRS, SRI, and TPMI (including the codebook) such that 8Tx UL operation can support four or more layers per WTRU in UL for CPE / FWA / vehicle / industrial devices. Potential limitations to the scope of this feature (e.g., including coherence assumptions, full / non-full power modes) may be identified.

[0083] The third feature may be to specify the following items, focusing on FR2 and multi-TRP to facilitate simultaneous multi-panel UL transmission for higher UL throughput / reliability, assuming a maximum of two TRPs and a maximum of two panels, and targeting CPE / FWA / vehicle / industrial devices (where applicable). The feature may include providing UL precoding instructions for PUSCH if no new codebook is introduced for multi-panel simultaneous transmission. Considering single-DCI and multi-DCI based multi-TRP operations, the total number of layers can be up to four across all panels, and the total number of codewords can be up to two across all panels. This feature can provide UL beam instructions for PUCCH / PUSCH, and an extension of the unified TCI framework in Objective 2 can be assumed considering single-DCI and multi-DCI based multi-TRP operations. For multi-DCI based multi-TRP operations, PUSCH+PUSCH, e.g., only PUSDH+PUSCH, or PUCCH+PUCCH can be transmitted across two panels within the same CC.

[0084] Enhancements to DMRS are disclosed herein. The enhancements to DMRS may relate to, for example, increasing the number of ports, supporting simultaneous multi-panel transmission, and / or supporting 8TX WTRUs. The disclosed enhancements to DMRS include procedures for cross-panel DMRS interference management. Cross-panel DMRS interference management may relate to, for example, solutions for cross-panel DMRS pairing and orthogonal / non-orthogonal mapping. The disclosed enhancements to DMRS may include procedures for enhanced OCC mapping. Enhanced OCC mapping may be related to using shared / duplicate OCC. The disclosed enhancements to DMRS may include procedures for increasing the number of DMRS ports. Increasing the number of DMRS ports may relate to, for example, new DMRS mapping patterns for SU / MU MIMO.

[0085] Procedures for cross-panel DMRS interference management may be provided. DMRS interference management may involve inter-panel DMRS pairing. The WTRU may receive permission to schedule PUSCH transmissions with its associated DMRS. This permission may include a field indicating the WTRU's antenna port configuration. In the case of a single DCI (sDCI), the WTRU may receive one antenna port field. If a single TRP is used, the WTRU may determine that the antenna port may be associated with DMRS transmissions to one TRP. If a multi-TRP (mTRP) repetition is scheduled, the WTRU may determine that the same antenna port configuration may be used for transmissions to both TRPs. If TDM'd transmissions are used, the PUSCH transmissions may include repetitions scheduled at different time instances (e.g., symbols or slots). The WTRU may be able to use two or more panels to simultaneously transmit PUSCH on the same slot or symbol to two or more TRPs. This mode of operation may be referred to as Simultaneous Multi-Panel (SMP).

[0086] The WTRU may receive an sDCI with two or more antenna port fields, and each antenna port field may be configured independently for each WTRU panel for SMP. The WTRU may determine the antenna port for each panel based on the ordering of the antenna port fields within the DCI. For example, the first antenna port may be associated with the first panel, TCI, or PMI, and the second antenna port may be associated with the second panel, TCI, or PMI.

[0087] The WTRU may determine that a single antenna port field can be associated with more than one panel. If the WTRU determines that it is being scheduled in SMP mode (e.g., explicitly, or through SRI / TCI, TPMI / PMI indications), the WTRU may determine that it can associate a first set of ports with a first panel and a second set of ports with a second panel. The WTRU may receive a {0,1} DMRS port indication and an explicit bitfield flag within the grant indicating the SMP operation mode. The WTRU may use port 0 for the first antenna panel and port 1 for the second antenna panel.

[0088] Reserved fields from the antenna port indication (e.g., values 12 - 15) may be reused to indicate the SMP operation mode. Upon receiving a grant indicating these values, the WTRU may choose to transmit in SMP. Each value may be mapped to a different combination and allocation of antenna ports per panel (e.g., SMP with port 0 for panel 0 and port 1 for panel 1; SMP with ports 0 - 1 for panel 0 and port 2 for panel 1; etc.).

[0089] The WTRU may receive a MAC - CE or UL - TCI that includes an indication of a DMRS port pair for SMP. The WTRU may use the SMP DMRS port pair indication in addition to the antenna port indication to determine whether the PUSCH is scheduled in SMP mode and the port allocation per panel. The WTRU may receive an antenna port indication for using ports 0 and 1. The WTRU may receive an indication that ports 0 and 1 can be paired for SMP. The WTRU may transmit ports 0 and 1 simultaneously on panels 0 and 1, respectively.

[0090] In multi-DCI mode (mDCI), the WTRU may receive separate DCIs, and each DCI may be sent from a different TRP. The WTRU may receive a separate antenna port indication from each grant. An additional field may be included as part of the antenna port indication to indicate whether SMP scheduling is performed between antenna ports. For example, if the WTRU receives an antenna port 0 indication for panel 0, an antenna port 1 indication for panel 1, and a bit indicating SMP, the WTRU may determine to transmit in SMP mode. The WTRU may receive a resource allocation in time / frequency, and this resource allocation may partially overlap between two mDCIs, for example, may only partially overlap. The WTRU may select to perform SMP when the resource allocations overlap, for example, only when they overlap.

[0091] DMRS mapping for SMP may be provided. The WTRU may be indicated to use rate matching to achieve the desired coded sequence length. For example, the WTRU may map its PUSCH transmission to a set of REs excluding the rate-matched REs that the WTRU does not transmit (i.e., skipped REs). The WTRU may be required to omit some coded bits from the output of the channel coder. The omitted bits may be defined as punctured from the sequence. Different puncturing patterns may be configured to reduce the interference of the rate-matched REs on the uplink or downlink. In the SMP operation mode, inter-panel interference may also be considered, and a rate matching pattern may be used to mitigate the interference.

[0092] The WTRU may determine different rate matching patterns according to its panel orthogonality. The WTRU may be composed of one or more antenna panels, and the antenna panels may have different orientations. For example, one antenna panel may face outward from the front of the device, and another antenna panel may face outward from the rear of the device. From the perspective of related interference, since the spatial filters may face in opposite directions, these directions may be quasi-orthogonal. The WTRU may be able to transmit simultaneously from both of these panels with low inter-panel interference. If so, the WTRU may not need to rate match around the PUSCH resources of the other panel.

[0093] As part of its capabilities, the WTRU may indicate a pair of panels with low inter-panel interference. Also, the WTRU may indicate a pair of panels with low inter-panel interference as part of a CSI report with an associated CRI index for each panel. For example, Panel 1 and Panel 2 may have low inter-panel interference. Based on this capability, the WTRU may be scheduled to transmit simultaneously on Panel 1 and Panel 2.

[0094] The WTRU may determine which panels are orthogonal based on Timing Advance (TA). If the difference between the TAs of two panels is less than a threshold, the WTRU may determine that the two panels are orthogonal and otherwise non-orthogonal.

[0095] The WTRU may receive a configuration for DMRS with two or more scrambling IDs. The DMRS sequence may be generated using a scrambler with a seed that is started by the scrambling ID. To further reduce inter-panel interference, if the panels are not orthogonal, the WTRU may select two different scrambling IDs and apply one scrambling ID for each DMRS sequence used for each panel. Otherwise, the WTRU may reuse the same scrambling ID for both panels.

[0096] The WTRU may determine to perform rate matching according to panel orthogonality. If the panels are orthogonal, the WTRU may determine not to apply rate matching, and if not, the WTRU may perform rate matching. The WTRU may include in the UCI an indication of whether the WTRU applies rate matching and to which antenna port / CDM group it applies. The WTRU may indicate a preferred CDM grouping for SMP as part of the WTRU capabilities or as part of a MAC-CE for SMP, where the WTRU may indicate panel pairing / association to the network. Alternatively, the WTRU may receive a pre-configured rate matching pattern when considering different panels. The rate matching pattern may be defined according to the OCC pattern or CDM group used for SMP.

[0097] When the WTRU is scheduled in SMP mode, the WTRU may determine to perform rate matching around the DMRS of one PUSCH transmission with respect to the other simultaneous PUSCH transmission. The WTRU may determine two different DMRS allocations, each DMRS allocation being associated with a respective panel. The WTRU may receive a rate matching pattern that may be applied when transmitting in SMP mode, for example, that may only be applied at this time. Alternatively, the WTRU may indicate port pairs that may be used for SMP and may indicate the rate matching pattern that the WTRU is using. The ports may belong to the same or different CDM groups.

[0098] Sparse DMRS transmission may be provided. To increase the capacity of a transmission port, e.g., a DMRS port, the DMRS port may be split into two or more groups, where a first set of DMRS ports may be sent within a first scheduled slot, a second set of DMRS ports may be sent within a second scheduled slot, etc. FIG. 3 shows an example of spreading DMRS ports over several slots. In the example shown in FIG. 3, to support 24 DMRS ports with an OCC length of 2, a first set of 12 DMRS ports may be sent within a first slot and a second set of DMRS ports may be sent within a second slot. For a given port, the mapping of DMRS in the frequency domain may vary from transmission to transmission.

[0099] The WTRU may receive an indication / configuration that the DMRS RE location (and / or phase-tracking RS (PTRS) RE location) may vary across PUSCH transmission instances (e.g., shifted based on a pre-configured / pre-defined pattern), where each of the PUSCH transmission instances is scheduled based on receiving the same codepoint of a DMRS-related field (e.g., the "antenna port" field) in the DCI that schedules each of the PUSCHs (and / or based on receiving the same second codepoint of a PTRS-related field, e.g., the "PTRS-DMRS association" field). In one example, the WTRU may transmit (e.g., be configured to transmit) DMRS only on a selected subset of DMRS ports that may be defined per RB and / or per slot based on the indication / configuration. The WTRU may determine the DMRS ports for transmission from the uplink antenna port indication in the scheduling DCI. Based on the determined DMRS ports for transmission, the WTRU may determine (e.g., update) the association of PTRS ports with at least one of the determined DMRS ports.

[0100] The symbol point may indicate / include at least one of several DMRS antenna ports that may correspond to, for example, the total number of PUSCH layers, and may be pre-configured by RRC and / or activated by MAC-CE. Each DMRS port number may correspond to each PUSCH layer of the PUSCH layer, the number of DMRS CDM groups without data, and the number of front-loading symbols, etc., where the number of DMRS antenna ports may be indicated by a separate field (for example, the pre-coding information and the layer number field). The second symbol point of the PTRS-related field may be pre-configured by RRC and / or activated by MAC-CE, for example, indicating the association between the PTRS port and the DMRS port.

[0101] The WTRU may determine, on a first PUSCH transmission instance (scheduled, for example, by a first DCI that schedules the first PUSCH), the first one or more DMRS RE positions corresponding to each DMRS port number indicated by symbol point C in the field of the first DCI (for example, the "antenna port" field), and / or the first one or more PTRS RE positions indicated by symbol point D of the PTRS-related field. In response to this determination, the WTRU may transmit the first PUSCH and DMRS and / or PTRS (associated with the first PUSCH or together with the first PUSCH) based on the first one or more DMRS RE positions and / or the first one or more PTRS RE positions.

[0102] In response to receiving an indication / configuration that the DMRS / PTRS RE positions can vary across a PUSCH transmission instance on a second PUSCH transmission instance of a PUSCH transmission instance (e.g., scheduled by a second DCI that schedules a second PUSCH), a WTRU can determine a second one or more DMRS RE positions corresponding to each DMRS port number indicated by a (e.g., same) symbol point C within a field (e.g., "antenna port" field) of the second DCI, and / or a second one or more PTRS RE positions indicated by a (e.g., same) symbol point D of a PTRS-related field. In response to this determination, the WTRU can transmit a second PUSCH along with DMRS and / or PTRS (associated with or together with the second PUSCH) based on the second one or more DMRS RE positions and / or the second one or more PTRS RE positions. The second one or more DMRS RE positions can be determined as a frequency domain shift version (e.g., X-RE up or down, e.g., X = 1, 2,... or X_max) of the first one or more DMRS RE positions based on the indication / configuration. The parameter / value of X can be indicated to or configured for the WTRU. The second one or more PTRS RE positions can be determined as a frequency domain shift version (e.g., P-RE up or down, e.g., P = 1, 2,... or P_max) of the first one or more PTRS RE positions based on the indication / configuration. The parameter / value of P can be indicated to or configured for the WTRU. X and P can be the same / identical (or indicated using a single parameter), e.g., based on the indication / configuration.

[0103] In response to receiving an indication / configuration that the DMRS / PTRS RE positions may vary across a third PUSCH transmission instance (e.g., scheduled by a third DCI that schedules the third PUSCH), the WTRU may determine one or more third DMRS RE positions corresponding to each DMRS port number indicated by a (e.g., same) symbol point C within a field (e.g., "antenna port" field) of the third DCI, and / or one or more third PTRS RE positions indicated by a (e.g., same) symbol point D of a PTRS-related field. In response to this determination, the WTRU may transmit the third PUSCH along with DMRS and / or PTRS (associated with or together with the third PUSCH) based on the one or more third DMRS RE positions and / or the one or more third PTRS RE positions. In some examples, the one or more third DMRS RE positions may be determined as a frequency domain shift version (e.g., Y-RE up or down, e.g., Y = 1, 2,... or Y_max) of the one or more first (or second) DMRS RE positions based on the indication / configuration. The parameter / value of Y may be indicated to or configured for the WTRU. The one or more third PTRS RE positions may be determined as a frequency domain shift version (e.g., Q-RE up or down, e.g., Q = 1, 2,... or Q_max) of the one or more first (or second) PTRS RE positions based on the indication / configuration. The parameter / value of Q may be indicated to or configured for the WTRU. Y and Q may be the same / identical (or shown using a single parameter) based on, e.g., the indication / configuration.

[0104] X and Y can be the same / identical (or can be indicated using a single parameter), for example, based on an indication / configuration. P and Q can be the same / identical (or can be indicated using a single parameter), for example, based on an indication / configuration. The third one or more DMRS (and / or PTRS) RE positions can be the same (e.g., identical) to the first one or more DMRS (and / or PTRS) RE positions, for example, based on an indication / configuration, which may imply that there are two alternating patterns in the DMRS (and / or PTRS) RE positions, such as the following exemplary order over a PUSCH transmission instance: the first one or more DMRS (and / or PTRS) RE positions, the second one or more DMRS (and / or PTRS) RE positions, the first one or more DMRS (and / or PTRS) RE positions, the second one or more DMRS (and / or PTRS) RE positions, and so on.

[0105] A gNB (or a second WTRU, e.g., for sidelink) that receives at least the DMRS (and / or PTRS) transmitted on the first one or more DMRS (and / or PTRS) RE positions and the second one or more DMRS (and / or PTRS) RE positions over a PUSCH transmission instance can apply interpolation (e.g., in the time / frequency domain) for wireless channel estimation (and / or channel phase tracking) for use in receiving at least one of the first PUSCH, the second PUSCH, the third PUSCH, etc., at least based on the DMRS (and / or PTRS) over the PUSCH transmission instance. This can improve the uplink performance (e.g., in terms of UL throughput and / or reliability) based on the effect of increasing the DMRS (and / or PTRS) density (e.g., in the frequency domain) based on at least the frequency domain shift version between the DMRS over the PUSCH transmission instance, thereby improving the wireless channel estimation performance.

[0106] DMRS mapping using repeated OCC can be provided. The OCC can be used to support multiplexing of transmit ports of a reference signal. FIG. 4 shows an exemplary use case of OCC for multiplexing of four DMRS ports. An example of an OCC having a length of 4 and no repeated OCC is shown. There may be no repetition of the OCC applied on different resources, and the same OCC group may be used for the entire scheduled band. A drawback of such a design may be that it is not always possible to have an RB with a self - contained OCC. As shown in FIG. 4, the first OCC may be entirely within the first scheduled RB, while the second OCC may not be and may extend into adjacent RBs. Thus, if the WTRU is not scheduled using adjacent RBs, some of the DMRS may become unavailable for channel estimation.

[0107] Multi - port reference signals can be multiplexed using repeated OCC. The WTRU can send multi - port reference signals using repeated OCC. The WTRU can receive multi - port reference signals using repeated OCC.

[0108] FIG. 5 illustrates the basic principle of repeated OCC for multi - port DMRS. Referring to FIG. 5, an OCC of length 2 is presented. The concepts presented are equally applicable to other OCC lengths. The principles presented may be used for various other applications including, for example: multiplexing and transmission of other types of signals such as CSI - RS, multiplexing of signals in other domains such as the time domain, either uplink transmission or downlink transmission, and / or cross - panel, cross - TRP port mapping, etc.

[0109] As illustrated in FIG. 5, two or more groups of OCCs can be used. A first group of OCCs can span and obtain over a first set of resource elements, and a second group of OCCs can span and obtain over a second set of resource elements. Some resource elements can be covered by two or more cover codes, where for the same transmission port, the cover code coefficients used by different OCC groups over the shared resource elements can be the same. For example, as shown in FIG. 5, at the shared location RE2, for each DMRS port, the OCC coefficients used by both groups are the same, e.g., +1 for group 1 and -1 for group 2.

[0110] As shown in FIG. 5, assuming equal channels over adjacent REs, the estimated channels for each DMRS port can be estimated as shown in the following chart.

[0111] [Table 1]

[0112] FIG. 6 shows an example of DMRS mapping with overlapping OCC length 4. In contrast to the mapping shown in FIG. 4, it may not be necessary to have two or more RBs scheduled such that they have OCC mappings for all DMRSs within a given RB. As shown in FIG. 6, each RB can be self - contained with two overlapping OCCs, and it may not be necessary to group the DMRS REs of different RBs so as to perform complete channel estimation. Although the text refers to DMRS mapping using overlapping OCCs, it will be understood that the disclosed concepts for performing DMRS mapping can be similarly applied, for example, to overlapping CDM groups.

[0113] Enhanced DMRS mapping may be provided. The PDSCH and PUSCH DMRS design patterns (e.g., without transform precoding) may support up to 12 orthogonal antenna ports for SU / MU-MIMO transmission. To improve the MIMO transmission system capacity, it may be useful to enhance the DMRS design to support more orthogonal ports without increasing the DMRS overhead in the existing NR architecture. PDSCH (or PUSCH) DMRS configuration patterns for CP-OFDM waveforms that support up to 24 orthogonal DMRS ports may be considered.

[0114] The WTRU may receive a DMRS configuration where the number of ports may be greater than 12. The WTRU may determine a pattern for DMRS transmission according to the received DMRS configuration. The WTRU may transmit DMRS according to one of the patterns discussed herein.

[0115] The first exemplary pattern ("Pattern 1") may correspond to the DMRS mapping for a CP-OFDM waveform as shown in FIG. 7. The second exemplary pattern ("Pattern 2") may correspond to the DMRS mapping for a CP-OFDM waveform as shown in FIG. 8. The number of RE allocations for the DMRS pilots per OFDM symbol may be reduced to correspond to scenarios where support for more than 12 orthogonal DMRS ports is required for DMRS configuration types 1 and 2. For the proposed DMRS Patterns 1 and 2 shown in FIGS. 7 and 8 respectively, the number of REs per OFDM symbol is reduced to 2 REs to support up to 24 orthogonal DMRS ports. OCC may be used to support multi-port operation. Depending on the DMRS configuration, the WTRU may transmit DMRS using length-2 OCC for single-symbol DMRS configurations or length-4 OCC for double-symbol DMRS configurations. Thus, DMRS Patterns 1 and 2 may support up to 12 orthogonal DMRS ports for single-symbol configurations and up to 24 orthogonal DMRS ports for double-symbol configurations.

[0116] The WTRU may receive a first semi-static or dynamic configuration that may include a configuration for a specific OCC length. The WTRU may receive, for example, a configuration for a 2-OCC length. As shown in FIGS. 7 and 8, the separation between the first RE and the second RE of the OCC may be different. The WTRU may determine the separation between the REs of the OCC pattern based on a dynamic indication. The WTRU may receive a dynamic indication, such as a MAC CE or DCI, to implicitly or explicitly indicate the separation of the REs within the configured OCC. For example, the WTRU may receive an indication to assume a separation of six REs, as shown in FIG. 7.

[0117] A third exemplary pattern ("Pattern 3") may correspond to the DMRS mapping for a CP-OFDM waveform as shown in FIG. 9. A fourth exemplary pattern ("Pattern 4") may correspond to the DMRS mapping for a CP-OFDM waveform as shown in FIG. 10. FIGS. 9 and 10 illustrate longer length OCCs that may be considered a mechanism for increasing the number of orthogonal DMRS ports in different use case scenarios. For the single-symbol DMRS configuration in DMRS Patterns 3 and 4, four antenna ports using the same REs may be orthogonalized by using a length 4-OCC. Conversely, for the double-symbol DMRS configuration, eight antenna ports sharing the same REs are orthogonalized using a length 8-OCC. DMRS Patterns 3 and 4 may support up to 12 orthogonal DMRS ports for the single-symbol configuration and up to 24 orthogonal DMRS ports for the double-symbol configuration.

[0118] Exemplary patterns may include overlapping OCCs. FIG. 11 shows an exemplary single-symbol 6-port DMRS mapping for a CP-OFDM waveform using an OCC of length 4. The WTRU may be configured to transmit or receive DMRS via 12 different DMRS ports using such a pattern. The REs shown using dark shading may be utilized for the first set of 6 ports, and the REs shown in white may be used for the second set of 6 ports. By employing two symbols and following the presented principle, the overall DMRS capacity can be increased to 24 ports.

[0119] In FIG. 11, an exemplary set of OCC codes for each port is shown. Other OCC codes may be used as well.

[0120] The WTRU may use a set of OCCs, where each element of an overlapping OCC may be the same on the overlapping REs. In FIG. 11, the second element of the OCC associated with ports 1 and 2 may be the same as the first element of the OCC associated with ports 3 and 4.

[0121] In an alternative form using a mapping similar to FIG. 11, for the last element of the OCC, it may proceed to the next RB or wrap around to the first pilot position.

[0122] For the exemplary 6-port DMRS mapping shown in FIG. 11, the channel estimate value h i for each port may be calculated based on the measurements at each DMRS position,

[0123]

Number

[0124]

Number

[0125] In the mapping of FIG. 11, other examples of the cover code matrix C may be considered, for example,

[0126] [Number] wherein,

[0127] [Number]

[0128] FIG. 12 shows an exemplary single-symbol DMRS that supports 12-port DMRS mapping using a length-4 repeated OCC. The WTRU may be configured to transmit or receive DMRS via 12 different DMRS ports using such a pattern. By adopting two symbols and following the presented principle, the overall DMRS capacity can be increased to 24 ports.

[0129] Channel estimation with enhanced accuracy may be provided. The capacity of the DMRS port configuration can be increased by increasing the length of the cover code in time or frequency. However, the accuracy of the estimation may decrease due to the assumption that there is no or very little change in the channel over the duration of the cover code. The accuracy of channel estimation can be enhanced by considering a sliding window over several DMRS transmissions. FIG. 13 shows the operation of a sliding window for enhancing channel estimation, where each OCC group indicated by the dotted ellipse may have not one estimate, but two estimates obtained from a first estimate and a second estimate window. The overall estimate can be enhanced by further processing such as averaging the two available estimates. The step for the sliding window can be one or more REs.

[0130] In an exemplary embodiment that employs DMRS mapping using duplicate cover codes, y, C, and h represent, respectively, the received DMRS RE, the cover code matrix, and the channel per port for a given estimation window, and y = Ch. In the example shown in FIG. 13, the first and second estimated values from the first and second estimation windows can be calculated as follows. h1 = C1 -1 y, h2 = C2 -1 y, where C1 and C2 can be the cover code matrices corresponding to the first and second estimation windows.

[0131] In an example with N estimation windows, the WTRU can estimate N estimated values for each port if and only if all the cover code matrices C1, C2,..., CN corresponding to the N estimation windows are invertible.

[0132] For example, in the case of the mapping shown in FIG. 11, both of the presented exemplary C matrices support such a feature. If

[0133]

Number

[0134]

Number

[0135]

Number

[0136] The WTRU may be configured to provide enhanced DMRS indication. The WTRU may be configured by the RRC using a DMRS type, such as a specific DMRS type, such as type I, type II, etc. The WTRU may receive dynamic indication for determining a mapping type, such as A or B, an assigned DMRS port, etc. for scheduled transmission.

[0137] The WTRU may receive a semi-static configuration for a P-port DMRS configuration where P = 24, where the configuration information includes one or more of the mapping attributes required for the definition of the P-port mapping in the time, frequency, and spatial domains, such as information regarding frequency mapping, time mapping, cover code, etc.

[0138] A WTRU may receive a dynamic indication, e.g., a DCI or a MAC CE, from which the WTRU may explicitly or implicitly determine and select a subset of DMRS ports from P configured DMRS ports for transmission. The dynamic indication may include information regarding one or more of: resource elements used for DMRS transmission, e.g., frequency and time mapping such as subcarriers, symbols, slots, etc.; information elements for determining a cover code used for multiplexing of multiple DMRS ports, e.g., an index; information elements for determining a transmission beam, e.g., an index; information elements for determining an associated panel for DMRS transmission, e.g., an index for specifying a panel for UL transmission or DL reception; information elements for determining a DMRS power offset for a primary transmission, e.g., PDSCH, PUSCH, etc., e.g., an index; an indication as to whether rate matching is to be performed around a subset of the indicated P ports or all P configured ports; an indication for determining OCC related information, e.g., length, sequence, etc.; an indication for determining timing information required for UL transmission, e.g., TA; an indication for specifying a DMRS sequence initialization seed for the indicated ports; and an indication for determining a PTRS association for the dynamically indicated ports. In an example where the dynamic indication includes an information element for determining a transmission beam, for PDSCH DMRS, multiple TCI information may be configured for the P configured ports. The WTRU may receive an index for selecting one of the configured TCIs for DMRS reception. In another example where the dynamic indication includes an information element, for PUSCH DMRS transmission, multiple SRIs may be configured for the P configured ports. The WTRU may receive an index for selecting one of the configured uplink beams for DMRS transmission.

[0139] Figure 14 shows an example of dynamic DMRS port indication and selection. A single-symbol DMRS mapping including six groups of 2-port DMRS each having a cover code of length 2 can be configured to support 12 DMRS ports. For example, using each dynamic indication that can be DCI, the WTRU can select a different set of ports for transmission for each transmission.

[0140] The WTRU can receive a first configuration by RRC, for example, to support P-port DMRS operation where P = 24, where the configuration information includes one or more of the mapping attributes required for the definition of the P-port mapping in the time, frequency, and spatial domains, such as information regarding frequency mapping, time mapping, cover code, etc. The WTRU can further receive DCI including information related to the DMRS ports.

[0141] In the case of CP-OFDM transmission, up to 5 bits and 6 bits can be used in the scheduling DCI to indicate the DMRS ports for uplink transmission and downlink transmission respectively, and in either case, not all code points are necessarily used. The WTRU can determine whether the DMRS ports indicated by the DCI can be based on a legacy or enhanced P-port DMRS configuration using one or more of the reserved code points / states within the received DCI, for example, the DCI field for antenna port indication.

[0142] When the WTRU, which can be set by RRC using DMRS mapping, for example, legacy DMRS mapping (e.g., dmrs-Type = 1, maxLength = 1, 4 bits are allocated for antenna port indication), and enhanced DMRS configuration, receives DCI format 1_1, the WTRU can determine whether the legacy or enhanced mapping is indicated by the DMRS antenna port field by checking one or more of the reserved states within the antenna port, such as states 12 to 15.

[0143] When the WTRU determines that the indicated DMRS port is from an enhanced DMRS configuration, the WTRU may interpret the content of the antenna port indication field in the decoded DCI according to the enhanced DMRS configuration mapping.

[0144] The WTRU may use one or more of: an RRC configuration for semi-statically configuring the enhanced DMRS configuration; a MAC CE for activating / deactivating the enhanced DMRS configuration, or alternatively, a MAC CE for activating the DMRS enhancement mapping based on a counter or for a preconfigured duration; for example, the WTRU capability when the WTRU declares uplink transmission using eight TX antennas; and an implicit indication based on another operation / configuration parameter or mode, such as mobility, multi-user operation mode, cell ID, etc., to determine whether the DMRS port indicated by the DCI can be based on a legacy or enhanced P-port DMRS configuration.

[0145] The WTRU may be configured to provide enhanced CDM grouping. The CDM group may be associated with an antenna port. The CDM group may be used to multiplex one or more DMRS ports in the code domain, and the orthogonal cover code may be used to multiplex one or more DMRS ports in the code domain. The CDM group may multiplex up to N DMRS ports. If the total number of DMRS ports (Ntot) can be greater than N (e.g., Ntot > N), two or more CDM groups may be used. For example, if Ntot = 2N, two CDM groups may be used to multiplex 2N DMRS ports. The time / frequency resources for one CDM group may be mutually exclusive with the time / frequency resources for another CDM group.

[0146] The set of DMRS ports may be configured, determined, or used for data transmission / reception (e.g., PDSCH, PUSCH), and one or more PTRS ports may be configured, determined, or used together with the set of DMRS ports. The presence / absence and / or pattern of PTRS may be determined based on at least one of the scheduling information (e.g., scheduling bandwidth, MCS, and waveform type including OFDM and DFT-s-OFDM).

[0147] The WTRU may determine the number of PTRS ports for data transmission / reception (e.g., PDSCH or PUSCH) based on one or more characteristics of the set of DMRS ports associated with the data transmission / reception. The set of DMRS ports associated with the data transmission / reception may be the DMRS ports used, determined, or selected for data transmission / reception for a given number of determined layers. One or more characteristics of the set of DMRS ports may include at least one of the DMRS type (e.g., type 1, type 2), the number of CDM groups associated with the set of DMRS ports used, determined, or selected for data transmission / reception, the DMRS density, the DMRS pattern, the CDM groups without data, the EPRE ratio between the DMRS and the PDSCH / PUSCH RE, or the antenna coherence level (full / partial coherence, non-coherent). The number of PTRS ports may be the same as the number of CDM groups associated with the set of DMRS ports used for data transmission / reception.

[0148] The PTRS port can be associated with a group of DMRS ports. Thus, the phase error measured from the PTRS port (e.g., common phase error) can be compensated for data using the DMRS ports within the group associated with the PTRS port. The group of DMRS ports can be determined based on the DMRS ports associated with the same CDM group. For example, in DMRS type 1, the DMRS ports {1, 2, 3, 4} may be associated with the first CDM group, the DMRS ports {5, 6, 7, 8} may be associated with the second CDM group, the first PTRS port may be associated with the DMRS ports in the first CDM group, and the second PTRS port may be associated with the DMRS ports in the second CDM group.

[0149] The PTRS port can be associated with the DMRS ports within a group of DMRS ports for phase error (e.g., common phase error) estimation and / or channel estimation. For example, the WTRU may perform phase error estimation by using the PTRS and the corresponding DMRS associated with the PTRS. In another example, the WTRU may perform channel estimation by using the DMRS and the corresponding PTRS. The DMRS ports within the group of DMRS ports associated with the PTRS port may be determined based on at least one of the DMRS port having the lowest DMRS index within the group and / or the DMRS port having the strongest power within the group, and the strongest power may be based on the modulation order (or MCS) determined for the DMRS port.

[0150] The group of DMRS ports can be determined based on the DMRS ports associated with the same antenna panel or antenna group. The WTRU may report its capabilities related to the antenna panel and its associated DMRS ports after the initial access procedure (e.g., during RRC connection setup), and the DMRS ports associated with the same antenna panel may be indicated as an antenna group.

[0151] The group of DMRS ports may be determined based on the antenna coherence in the WTRU (e.g., full / partial coherent, non - coherent). For example, if the WTRU may have fully coherent antennas (or may be shown to have fully coherent antennas as a capability), the group of DMRS ports may be all the DMRS ports that are configured or used. If the WTRU may have partially coherent antennas (or may be shown to have partially coherent antennas as a capability), the group of DMRS ports may be based on the DMRS ports associated with the CDM group. If the WTRU may have non - coherent antennas (or may be shown to have non - coherent antennas as a capability), each DMRS port may be determined as a group.

[0152] An indication of the CDM group may be provided. The WTRU may indicate a set of configured DMRS ports that are associated with the PTRS port. The configured DMRS ports may belong to the same or different CDM groups. For example, if the WTRU receives a configuration for DRMS type 1, the subset of the configured DMRS ports may belong to either CDM group 0 or group 1. Also, if the WTRU may be configured with DRMS type 2, the subset of the DMRS ports may belong to either CDM group 0, 1, or 2. The WTRU may use the CDM group to determine the DMRS ports associated with the PTRS port. The set of configured DMRS ports for the PTRS - DMRS association may be from the same CDM group.

[0153] When PTRS transmission is configured, the WTRU may receive a configuration indicating the CDM group mapping of the DMRS ports associated with one or more of the PTRS ports for data transmission / reception. This configuration may include a list of different CDM group mappings, where each mapping may be assigned a symbol point (i.e., a bit). The WTRU may receive a DCI that may include a bit field for indicating the symbol points corresponding to each mapping. There may be an option to reuse an existing bit field in the DCI to indicate the CDM group mapping. For example, in a DCI for uplink transmission, bits, e.g., up to 5 bits, may be available for use for DMRS-antenna port indication. Some of the symbol points may not be used, or may be used to indicate different CDM group mappings. The WTRU may determine the CDM group of the DMRS ports associated with the PTRS ports by checking one of the reserved symbol points within the antenna port field of the DCI. The WTRU may transmit PTRS along with a set of DMRS ports, where the set of DMRS ports may be mapped to the indicated CDM group.

[0154] The WTRU antenna layout may be divided into antenna panels or antenna groups, where each antenna group includes a subset of the WTRU antennas. Each antenna group may be composed of the same or a different number of TX antennas. The WTRU may receive a configuration where the DMRS ports associated with the PTRS ports for each antenna group may be from the same CDM group.

[0155] Existing fields within the DCI can be used to indicate CDM group mappings for DMRS ports associated with the PTRS port. For example, the PTRS-DMRS association field within the DCI can be used for a CDM group indication where each symbol point is assigned a CDM group (e.g., 0 → CDM0, 1 → CDM1, 2 → CDM2, 3 → reserved). The WTRU can receive a DCI having an indication of the CDM group and then transmit the PTRS along with one of the DMRS ports from the indicated CDM group. For example, if the value 0 is indicated in the PTRS-DMRS association DCI field, the DMRS associated with the PTRS port may be mapped to CDM group 0 and the WTRU may transmit the PTRS along with the DMRS port of CDM group 0.

[0156] The WTRU can receive a configuration where each antenna group can be mapped to a different CDM group. The configuration can include a list of all possible combinations of CDM groups and antenna group mappings. The WTRU can receive an indication within a DCI having a CDM group for each antenna group and then the WTRU can transmit the PTRS with one of the DMRS ports of the indicated CDM group for each antenna group. For example, some reserved symbol points within the antenna port DCI field can be used to indicate CDM group assignments and each symbol point can include one of the possible combinations of CDM group and antenna group mappings. In the case of DMRS type 1 and two antenna groups, the reserved symbol point can have its input as "01" and rules can be assigned such that the first number indicates that the DMRS port within the first antenna group can be mapped to CDM group 0 and the second number can indicate that the DMRS port within the second antenna group can be mapped to CDM group 1.

[0157] Enhanced DMRS mapping can be provided. The enhanced DMRS mapping can be associated with MU-MIMO transmission. OCC can be used to support transmission port multiplexing associated with a reference signal. In the NR DMRS design, an OCC length of 2 can be used to multiplex DMRS ports so that OCC pairing can be within a single RB. To support more DMRS ports, an OCC length of 4 can be used. In the Type 1 DMRS configuration, since there can be 6 DMRS REs per PRB, when using an OCC length of 4, the leading DMRS REs can be covered by the first OCC, but the last remaining 2 DMRS REs can be bundled with the leading DMRS REs of adjacent PRBs to complete the next set of OCC mapping. When a longer OCC length can be used (e.g., length 4), an orphan resource element (RE) problem can occur - that is, if the number of REs for DMRS within a resource block is not a multiple of the OCC length, remaining unmapped REs can occur. In the case of MU-MIMO transmission, the orphan RE problem can exist when two or more WTRUs can be scheduled at two different starting PRBs.

[0158] Figure 15 shows exemplary cases of MU-MIMO transmission with and without FD shift of OCC mapping. Referring to section (a) of Figure 15, an exemplary case of MU-MIMO transmission configured with DMRS Type 1 having an FD-OCC length of 4 can be shown. Two WTRUs, each composed of two DMRS ports, can be scheduled at the same starting PRB for their PDSCH resource mapping. Thus, the OCC mapping for co-scheduled WTRUs can be aligned (e.g., fully aligned) to enable proper orthogonality of the DMRS ports associated with the two WTRUs.

[0159] Referring to section (b) of FIG. 15, another exemplary case of MU-MIMO transmission configured with DMRS type 1 having an FD-OCC length of 4 can be shown. Two WTRUs, each composed of two DMRS ports, can be scheduled using different starting PRBs for their PDSCH resource mapping. As shown in section (b) of FIG. 15, the starting PRB of the scheduled transmission of WTRU1 is at PRB0, and the starting PRB of the scheduled transmission of WTRU2 is at PRB1. The PDSCH allocations cannot be aligned due to the different starting PRBs, and the OCCs can be mismatched and cannot be used for DMRS port orthogonalization.

[0160] Referring to section (c) of FIG. 15, an exemplary solution for the case of MU-MIMO transmission configured with DMRS type 1 having an FD-OCC length of 4 can be shown when the starting PRBs of the scheduled PDSCH transmissions are not the same or are not separated by an even number of PRBs. For proper orthogonalization and separation of the DMRS ports, the starting RE of the OCC of one of the WTRUs can be shifted by half of the OCC length. As shown in section (c) of FIG. 15, the starting PRB of the scheduled transmission of WTRU2 can be at PRB1, and the start of the complete OCC at PRB1 can be at the third DMRS RE. As a result of this shift, the remaining set of OCCs can be aligned, for example, can be fully aligned.

[0161] If the WTRU can be configured with an FD-OCC length that results in some orphan REs, the WTRU can align its mapping with another scheduled transmission using the FD-shifted version of the OCC mapping. The WTRU can determine whether to perform the FD shift, for example, the usefulness or necessity of performing it, based on one or more of several implementations. In a first implementation for determining whether to perform the FD shift, the WTRU can receive a dynamic indication to shift the OCC mapping for the scheduled transmission. The indication can be received as part of the scheduling DCI or can be separately indicated by MAC-CE as needed.

[0162] In a second implementation form for determining whether to perform FD shifting, the WTRU may determine the FD shift of the OCC from the index of the reference PRB of the scheduled PDSCH transmission, for example, the index of the first PRB. The WTRU may determine the FD shift of the OCC if the index of the first PRB of the scheduled PDSCH transmission is odd.

[0163] In a third implementation form for determining the usefulness, e.g., necessity, of FD shifting, the WTRU may determine the FD shift of the OCC from the indicated set of antenna ports. The first group of antenna ports may be associated with the first OCC mapping, and the second group of antenna ports may be associated with the second OCC mapping. Although the text refers to performing alignment by shifting the OCC mapping, it will be understood that the disclosed concept for performing alignment to prevent orphan resources may be similarly applied, for example, to CDM groups.

[0164] An enhanced PTRS configuration may be provided. A PTRS configuration for the M-TX WTRU may be provided. In the case of uplink transmission, the WTRU may divide the M-TX antenna set into K antenna groups, each composed of N TX antennas per antenna group, where N ≤ M. Further, the antennas within each antenna group may be assumed to be coherent. For the sake of brevity in presenting the gist, it is assumed that each antenna group has the same number of TX antennas, but the same implementation form presented below may also be applicable when the antenna groups have different numbers of TX antennas. The WTRU having K antenna groups may be composed of one or more DMRS ports per antenna group. The indicated DMRS ports for each antenna group may be mapped to the same CDM group.

[0165] The WTRU may be composed of two or more PTRS reference signals to assist in phase tracking at the gNB. The PTRS-DMRS association may be realized, for example, when the WTRU can indicate the number K of antenna groups in an implicit or explicit manner. Upon receiving the indication, the WTRU may be indicated one or more PTRS ports. The WTRU may be indicated K or fewer PTRS ports according to the indicated K antenna groups.

[0166] The PTRS-DMRS association may be realized, for example, when the WTRU can receive an explicit or implicit indication regarding a preferred antenna group for PTRS transmission, for example, the antenna group having the strongest uplink transmission. The indication may be in the form of an information element indicated in DCI or MAC CE, or alternatively by SRI. The WTRU may then transmit the PTRS using the indicated antenna group.

[0167] The PTRS-DMRS association may be realized, for example, within an antenna group, and the PTRS port may be associated with the DMRS port having the lowest index associated with the antenna group.

[0168] PTRS-DMRS association may be realized. For example, a WTRU having K antenna groups may cycle PTRS transmissions over the K antenna groups. The cycle length may be fixed or indicated by semi-static or dynamic signaling. The WTRU may be indicated to cycle the PTRS ports based on one or more of the following: per transmission grant, e.g., for the first transmission, antenna group X may be used and for the second transmission, antenna group Y may be used; slot number, e.g., according to odd / even every X slots; the cycle may follow a pseudo-random sequence that may be initialized by a seed. The seed may be explicitly indicated to the WTRU or may be implicitly determined from other configuration parameters. Also, the RB position for PTRS mapping may change with each cycle of PTRS transmission from the antenna group.

[0169] An indication of PTRS-DMRS association may be provided. In the NR uplink, the WTRU may determine the PT-RS port to DM-RS port association according to the indication received in the DCI and according to the WTRU capabilities. Ports, e.g., up to two PT-RS ports may be indicated. In the case of a fully coherent WTRU, a single PT-RS port may be used, while a partially coherent or non-coherent WTRU may use two PT-RS ports. In the case of non-codebook, the WTRU may receive a DCI having an SRI indicating the SRS resource. The WTRU may receive an SRS configuration (ptrs-PortIndex in SRS-Config) indicating the PT-RS port associated with each SRS resource. In the case of codebook, the WTRU may receive a DCI having a 2-bit field PTRS-DMRS association. When one PTRS port is used, it may indicate one of four antenna ports, and the DMRS port mapped to the indicated antenna port may be associated with the PTRS port. When two PTRS ports may be used, the MSB and LSB of the DCI field may indicate one of the antenna ports for PTRS.

[0170] However, when more antenna ports can be considered, there may be no rules for mapping PT-RS ports to DMRS.

[0171] A MAC-CE based PTRS-DMRS port association may be provided. One exemplary implementation may be to increase a bit field in the DCI and dynamically indicate all, for example, all new possible combinations resulting from an increase in DMRS ports. FIG. 16 shows an exemplary Table 1 showing a PTRS-DMRS single port association for eight DMRS ports. In Table 1, when a single PTRS port is used, 3 bits may be used to define an association for up to eight DMRS ports. The WTRU may receive a table configured by RRC, and the DCI may indicate one of the values of the table. Different tables showing PTRS-DRMS port associations may be configured depending on the situation, for example, may be configured for each serving cell, and the use of the table may be conditional on the presence of one or more additional configurations and / or WTRU capabilities (e.g., 8TX).

[0172] The WTRU may determine a PTRS-DMRS port association according to a MAC-CE that may indicate one of the values from a table such as Table 1 shown in FIG. 16. The MAC-CE may include an explicit indication of the association between the indicated DMRS and the PT-RS port. The WTRU may receive a MAC-CE having an indication of one of eight ports from a DMRS index. The exemplary table shown in FIG. 16 provides an exemplary mapping associating one value with a DMRS port, and this value represents the same numerical value as a bit string (e.g., 3 bits). The MAC CE may further include a field indicating one or more serving cells and / or cell IDs to which the association applies. When a single PTRS port may be used, the MAC-CE may include a 3-bit indication field, and the WTRU may use the 3-bit indication to determine on which DMRS port to transmit the PTRS. The single PTRS port may be associated with the DMRS. The WTRU may use the PTRS-DMRS port association until it receives another MAC-CE that activates a different association. When receiving the MAC CE by the MAC entity, the WTRU may transfer the content of the MAC CE to the lower layer for processing.

[0173] The MAC CE may indicate that the association is deactivated. When receiving a deactivated MAC CE, the WTRU may no longer consider the association valid and may revert to a default and / or alternative association. Whether the MAC CE activates and / or deactivates the association may be explicitly indicated via a field identified, for example, by a flag bit.

[0174] The WTRU may receive a MAC-CE having an 8-port DMRS index and two or more PTRS port indexes. The PTRS ports may be explicitly associated with the DMRS ports via a mapping as shown in Table 1 shown in FIG. 16. The WTRU may receive an additional rule for determining one DMRS when multiple DMRS ports are associated with the same PTRS port. This rule may be based on, for example, the lowest scheduled DMRS port among all ports associated with the same DMRS port.

[0175] In one example, the MAC-CE may include an instruction for mapping DMRS ports 1-4 to a first PTRS port and DMRS ports 5-8 to a second PTRS port. After receiving the MAC-CE, the WTRU may receive DCI for scheduling a PUSCH having 8TX. Based on the activation of the received MAC-CE, the WTRU may transmit two-port PTRS together with UL DMRS transmitted on the PUSCH. The WTRU may determine to transmit two PTRS, where the first PTRS is associated with the lowest DMRS port (scheduled port 1) within the first group, and the second PTRS port may be associated with the lowest DMRS port (scheduled port 5) within the second group.

[0176] Upon receiving DCI indication and / or activation / deactivation of the MAC CE, the WTRU may assume that the configuration may be valid for a certain period and / or number of resources. Upon receiving DCI and / or activation / deactivation of the MAC CE, the WTRU may start a prohibit timer, and the WTRU may not assume that it will receive an updated value. The WTRU may discard any subsequent DCI values and / or activation / deactivation of the MAC CE received during this time, for example.

[0177] In the absence of DCI indication and / or activation of MAC CE, the WTRU may select the applicable default value. The default value may be based on configuration information or, alternatively, may be indicated, for example, via system information. When the WTRU may receive the value indicated by the DCI and / or the activated association of the MAC CE, the WTRU may apply this value for, for example, one or more of the following durations: during the transmission and / or reception scheduled by the DCI; for a specific duration after DCI reception and / or activation of the MAC CE; or until a subsequent DCI and / or MAC CE indicates a value and / or association different from the previously indicated one. If the applicable duration is during a specific duration after DCI reception and / or activation of the MAC CE, the WTRU may assume that this value is valid for the next X seconds and / or for Y transmissions / receptions. Upon receiving a DCI or MAC CE, the WTRU may start a timer or counter. When the counter expires, the WTRU may, for example, return to the default value and / or assume and / or request an updated value.

[0178] The WTRU may request a PTRS-DMRS port association from the network. This request may be via MAC CE, UCI, or RRC signaling and may be specific to a cell and / or a PTRS port. The WTRU may send such a request, for example, at one or more of the following events: upon expiration of the validity of the association (e.g., upon expiration of a timer and / or counter); upon RRC reconfiguration (e.g., upon reconfiguration of the PTRS-DMRS port association table); upon beam failure detection (BFD) and / or beam failure recovery (BFR); upon radio link failure (RLF); upon RRC state transition (e.g., upon transition to and / or from the RRC_IDLE, RRC_INACTIVE, RRC_CONNECTED states), etc.

[0179] In response to mobility to a new cell, the WTRU may be provided with a PTRS-DMRS port association as part of an RRC reconfiguration. Alternatively, the WTRU may receive an indication (e.g., within a handover command) that the PTRS-DMRS association is the same as and / or different from the current serving cell.

[0180] The PTRS-DMRS port association may be based on DCI and MAC-CE. The MAC-CE may activate or indicate a PTRS-DMRS port association from a subset of all possible associations. The WTRU may dynamically select one of the indicated associations from the MAC-CE according to a field within the DCI. The WTRU may receive, for example, a MAC-CE field having a 2-bit field configured as shown in Table 2 of FIG. 17. Table 2 shows a configured subset of PTRS-DMRS port associations. Table 2 may include a subset of the fields included in Table 1 as shown in FIG. 16. After receiving the MAC-CE, the WTRU may receive DCI that schedules a PUSCH, and the DCI may reuse an existing PTRS-DMRS association field within the DCI to signal one of the PTRS-DMRS port association fields from the subset shown in Table 2 of FIG. 17. For example, if the WTRU may receive a PTRS-DMRS association value 2, the WTRU may determine to transmit the PTRS on the same port as the fifth scheduled DMRS port based on the information in Table 2 of FIG. 17.

[0181] If more than one PTRS port may be used, the set of DMRS ports may be associated with the PTRS ports according to the row index of a table such as Table 3 shown in FIG. 18. Table 3 shows a configured subset of PTRS-DMRS port associations for the two-port case. If the WTRU receives the value 2, the WTRU may determine, based on the information in Table 3, that the first and fifth scheduled DMRS ports may be associated with the first and second PTRS ports, respectively.

[0182] Dynamic PTRS field reinterpretation may be performed based on the actual number of layers. The WTRU may determine that one or more symbol points of a PTRS field in the DCI (e.g., the "PTRS-DMRS port association" field) may be reinterpreted based on the actual number of layers that may be indicated with the DCI (or in relation to the DCI, or by a second field of the DCI that indicates the actual number scheduled (e.g., the "precoding information and number of layers" field)).

[0183] In response to determining that the actual number of layers is less than or equal to L, the WTRU may apply a predefined or preconfigured PTRS field (e.g., the "PTRS-DMRS port association" field). L may be 2 in the case of 4-Tx UL operation mode. L may be 4 in the case of 8Tx UL operation mode. The predefined or preconfigured PTRS field may be based on Table 4 (for 1 PTRS port) and Table 5 (for 2 PTRS ports) as shown in FIG. 19. Table 4 shows an exemplary predefined or preconfigured PTRS-DMRS port association for the case of 1 port (when the actual number of layers ≦ L). Table 5 shows an exemplary predefined or preconfigured PTRS-DMRS port association for the case of 2 ports (when the actual number of layers ≦ L).

[0184] In response to determining that the actual number of layers (e.g., indicated by K) is greater than L, the WTRU may apply a second re-interpreted PTRS field (e.g., a "PTRS-DMRS port association" field) that is pre-configured / indicated (e.g., via RRC and / or MAC-CE). L may be 2 in the case of 4-Tx UL operation mode. L may be 4 in the case of 8Tx UL operation mode. The second re-interpreted PTRS field may be based on Table 6 (for 1 PTRS port) and Table 7 (for 2 PTRS ports) shown in FIG. 20 below. Table 6 shows an exemplary (second) re-interpreted PTRS-DMRS port association for the case of 1 port (when the actual number of layers (K) > L). Table 7 shows an exemplary (second) re-interpreted PTRS-DMRS port association for the case of 2 ports (when the actual number of layers (K) > L).

[0185] In Table 6, the value (or symbol point) of the second re-interpreted PTRS field (for 1 port) may indicate the f(K)-th scheduled DMRS port or the g(K)-th scheduled DMRS port, where f(K) or g(K) may be a pre-configured / indicated function with respect to K (as the actual number of layers). f(K) may be pre-configured or indicated such that f(K) = K - 1, and g(K) may be pre-configured or indicated such that g(K) = K. If the WTRU may determine that the actual (scheduled) number of layers K may be 5 (>L), the WTRU may interpret that, based on f(5) = 5 - 1 = 4, the value (or symbol point) 2 may be the "4th scheduled DMRS port", and based on f(5) = 5, the value (or symbol point) 3 may be the "5th scheduled DMRS port". If the WTRU may determine that the actual (scheduled) number of layers K may be 7 (>L), the WTRU may interpret that, based on f(7) = 7 - 1 = 6, the value (or symbol point) 2 may be the "6th scheduled DMRS port", and based on f(7) = 7, the value (or symbol point) 3 may be the "7th scheduled DMRS port".

[0186] The WTRU may receive different functions of f(K) and g(K) (e.g., via pre-configured or pre-indicated ones), which may provide benefits in terms of flexibility in allocating different PTRS-DMRS mapping patterns and improving performance based on a flexible association between the PTRS ports and the DMRS ports.

[0187] In Table 7, the value (or symbol point) of the second re-interpreted PTRS field (for the 2-port case) may indicate the DMRS port of h(K) that shares PTRS port 0, or the DMRS port of i(K) that shares PTRS port 1, where h(K) or i(K) is a pre-configured / pre-indicated function with respect to K (as the actual number of layers). The WTRU may determine which DMRS port is shared with PTRS port 0 or 1 based on a pre-configured upper layer message (or parameter). For example, RRC (and / or MAC-CE) parameters may configure / indicate such a linkage between the DMRS ports and the PTRS ports that are shared with each other. h(K) may be pre-configured or pre-indicated such that h(K)=floor(K / 2), and i(K) may be pre-configured or pre-indicated such that i(K)=floor(K / 2). The function floor(A) may imply referring to an integer that may or may not exceed the input value A to this function. If the WTRU may determine that the actual (scheduled) number of layers K is 5 (>L), the WTRU may interpret that based on h(5)=floor(5 / 2)=2, the value 1 of the MSB may be the "second DMRS port that shares PTRS port 0", and based on i(5)=floor(5 / 2), the value 1 of the LSB may be the "second DMRS port that shares PTRS port 1". If the WTRU may determine that the actual (scheduled) number of layers K is 7 (>L), the WTRU may interpret that based on h(7)=floor(7 / 2)=3, the value 1 of the MSB may be the "third DMRS port that may share PTRS port 0", and based on i(7)=floor(7 / 2), the value 1 of the LSB may be the "third DMRS port that may share PTRS port 1".

[0188] The WTRU may receive different functions of h(K) and i(K) as pre-configured or indicated, which may result in benefits in terms of flexibility when allocating different PTRS-DMRS mapping patterns and improving performance based on a flexible association between the PTRS port and the DMRS port.

[0189] (As a threshold of the layer domain), the parameter of L may be configured or indicated to be 2 or more, meaning that L1, L2,... may be configured or indicated. For example, in the case of the 8Tx UL operation mode, L1 may be set to 4 and L2 may be set to 6, where the WTRU may be configured or indicated with an additional (third) re-interpreted PTRS-DMRS port association table (or field). The second re-interpreted PTRS-DMRS port association table (or field) may be applicable to L1 < K ≤ L2, and the third re-interpreted PTRS-DMRS port association table (or field) may be applicable to K > L2, and so on.

[0190] The WTRU may perform reporting (transmission) of WTRU capability parameters / information related to (e.g., based on) at least one of L, L1, L2, f(K), g(K), h(K), and i(K). Based on receiving such a WTRU capability report from the WTRU, the gNB may configure or indicate at least one of L, L1, L2, f(K), g(K), h(K), and i(K) to determine the re-interpretation behavior for PTRS-DMRS port association and the PTRS port mapped to the DMRS port.

[0191] The WTRU may be configured to associate a group of DMRS ports with a code division multiplexing (CDM) group and map the group of DMRS ports associated with the CDM group to a group of antenna groups. The WTRU may be configured to determine to map the PTRS port to the DMRS port based on the MCS value associated with the DMRS port.

[0192] FIG. 21 shows an exemplary implementation for antenna groups and PTRS-DMRS determination, where each CDM / DMRS group can be mapped to a different antenna group. FIG. 22 shows an exemplary CDM / DMRS mapping to antenna groups for 8-layer transmission. In the example shown in FIG. 22, the mapping from CDM to antenna groups can be shown for 8-layer transmission where each CDM group can have a length of 4.

[0193] Referring to the exemplary implementation shown in FIG. 21, a WTRU, which can be referred to as a UE in FIG. 21, can report information regarding its coherence capabilities and antenna layout, for example, can report (e.g., indicate) it implicitly or explicitly. The information shown can include, for example, the number Ng of antenna groups. As shown in the illustration, this information can indicate, for example, one coherent antenna group (Ng = 1) of eight transmitters, or two groups (Ng = 2) of four coherent transmitters. Based on the antenna grouping shown, a network device, such as a base station (e.g., gNB used as an example in this specification), can schedule uplink transmission and send to the WTRU scheduling DCI, for example, information for scheduling PUSCH transmission, and information regarding DMRS antenna ports and one or more PTRS ports.

[0194] The WTRU can receive DCI that includes association information for scheduling transmission, for example, PUSCH transmission, and / or associating DMRS ports with CDM groups. The DCI can include information regarding DMRS antenna ports and one or more PTRS ports.

[0195] Based on the association information indicated in the DCI, the WTRU can associate or relate a first set of DMRS ports with a first CDM group, or associate or relate a second set of DMRS ports with a second CDM group.

[0196] The WTRU may map a first set of DMRS ports associated with a first CDM group to a first antenna group and may map a second set of DMRS ports associated with a second CDM group to a second antenna group. If the WTRU includes one coherent antenna group, e.g., when Ng = 1, the WTRU may map each determined CDM group (and associated DMRS group) to one antenna group. A WTRU composed of two or more CDM groups may map the DMRS ports of each antenna group to the same CDM group.

[0197] The WTRU may transmit a scheduled transmission which may be, for example, a PUSCH transmission. This transmission may include at least a first DMRS transmitted using a first set of DMRS ports and a first antenna group and at least a second DMRS transmitted using a second set of DMRS ports and a second antenna group.

[0198] The received DCI may indicate one or more PTRS ports. If one PTRS port is configured or indicated, the WTRU may map this one PTRS port to a first DMRS port within the first or second set of DMRS ports. The first DMRS port may be determined based on the MCS associated with the first DMRS port, and based on the mapping to the first DMRS port, the PTRS may be transmitted using one PTRS port. The DMRS port having the strongest link for uplink transmission, which may be determined based on the associated MCS, e.g., the highest MCS value among the MCS values associated with the first or second set of MRS ports, may be used for PTRS transmission.

[0199] If two or more PTRS ports are configured or indicated, the WTRU may map a first PTRS port to a first DMRS port that may be mapped to a first antenna group, and may map a second PTRS port to a second DMRS port that may be mapped to a second antenna group. The WTRU may transmit at least a first PTRS using the first PTRS port based on the mapping to the first DMRS port, for example, using PUSCH transmission and DMRS, and may transmit at least a second PTRS using the second PTRS port based on the mapping to the second DMRS port.

[0200] The features and elements described herein are described in specific combinations, but each feature or element may be used alone without the other features and elements of the preferred embodiments, or may be used in various combinations with or without other features and elements.

[0201] The descriptions herein may be provided for illustrative purposes and are in no way intended to limit the applicability of the systems, methods, and means described to other wireless technologies and / or wireless technologies using different principles when applicable. The term network in this disclosure may refer to one or more gNBs that may be associated with one or more Transmission / Reception Points (TRPs) and / or any other nodes within a radio access network.

[0202] It will be understood that the implementations described herein may take into account 3GPP-specific protocols, but the implementations described herein are not limited to this scenario and may be applicable to other wireless systems. For example, the solutions described herein take into account LTE, LTE-A, New Radio (NR), or 5G-specific protocols, but it will be understood that the solutions described herein are not limited to this scenario and are also applicable to other wireless systems.

[0203] The processes described herein may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, magnetic media such as read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks, magneto-optical media, and / or optical media such as compact disc (CD)-ROM disks, and / or digital versatile disk (DVD), etc. A processor associated with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and / or any host computer.

Claims

1. A processor, receiving downlink control information (DCI) including information for scheduling a transmission and associating a demodulation reference signal (DMRS) port with a code division multiplexing (CDM) group, associating, based on the DCI, a first one or more DMRS ports with a first CDM group, associating, based on the DCI, a second one or more DMRS ports with a second CDM group, mapping the first one or more DMRS ports associated with the first CDM group to a first antenna group, mapping the second one or more DMRS ports associated with the second CDM group to a second antenna group, and configured to send the transmission including at least a first DMRS sent using the first one or more DMRS ports and the first antenna group and at least a second DMRS sent using the second one or more DMRS ports and the second antenna group, a wireless transmit / receive unit (WTRU) comprising the processor.

2. The WTRU according to claim 1, wherein the processor is further configured to send information associated with at least one of a coherence capability or an antenna layout.

3. The WTRU according to claim 2, wherein the information associated with at least one of the coherence capability or the antenna layout includes information identifying one or more coherent antenna groups.

4. The WTRU according to claim 3, wherein the information identifying one or more coherent antenna groups includes information identifying the number of antenna groups.

5. The WTRU according to claim 3, wherein the information for scheduling the transmission and associating a DMRS port with a CDM group is based on the information identifying one or more coherent antenna groups.

6. The WTRU according to claim 1, wherein the processor configured to receive DCI is configured to receive DCI from a base station.

7. The processor, determining a first DMRS port based on a modulation and coding scheme (MCS) value associated with the first DMRS port from among the first one or more DMRS ports or the second one or more DMRS ports, Further configured to associate a first phase tracking reference signal (PTRS) port with the first DMRS port, The WTRU according to claim 1, wherein the transmission further comprises a PTRS sent using the first PTRS port. **Claim 8** The processor configured to determine the first DMRS port based on the MCS value is further configured to determine the first DMRS port based on that the MCS value is the highest MCS value associated with the first one or more DMRS ports or the second one or more DMRS ports. The WTRU according to claim 7. **Claim 9** The WTRU according to claim 7, wherein the DCI includes information indicating the first PTRS port. **Claim 10** The processor is associating a first PTRS port with a first DMRS port mapped to the first antenna group, further configured to associate a second PTRS port with a second DMRS port mapped to the second antenna group, The WTRU according to claim 3, wherein the transmission further comprises a first PTRS sent using the first PTRS port and a second PTRS sent using the second PTRS port. **Claim 11** The WTRU according to claim 10, wherein the DCI includes information indicating a plurality of PTRS ports. **Claim 12** The WTRU according to claim 1, wherein the transmission further comprises a physical uplink shared channel (PUSCH) transmission. **Claim 13** A method of port mapping, comprising: receiving downlink control information (DCI), wherein the DCI includes information for scheduling a transmission and associating a demodulation reference signal (DMRS) port with a code division multiplexing (CDM) group; associating a first one or more DMRS ports with a first CDM group based on the DCI; associating a second one or more DMRS ports with a second CDM group based on the DCI; mapping the first one or more DMRS ports associated with the first CDM group to a first antenna group; mapping the second one or more DMRS ports associated with the second CDM group to a second antenna group. Sending the said transmission, the said transmission including at least a first DMRS sent using the said first one or more DMRS ports and the said first antenna group, and at least a second DMRS sent using the said second one or more DMRS ports and the said second antenna group, and a method including this.

14. The method according to claim 13, further including sending information associated with at least one of a coherence capability or an antenna layout.

15. The method according to claim 14, wherein the information associated with at least one of the coherence capability or the antenna layout includes information specifying one or more coherent antenna groups.

16. The method according to claim 15, wherein the information specifying one or more coherent antenna groups includes information specifying the number of antenna groups.

17. The method according to claim 15, wherein the information for scheduling the said transmission and associating DMRS ports with CDM groups is based on the information specifying one or more coherent antenna groups.

18. Receiving DCI includes receiving DCI from a base station, the method according to claim 13.

19. Determining a first DMRS port based on a modulation and coding scheme (MCS) value associated with the said first DMRS port, from among the said first one or more DMRS ports or the said second one or more DMRS ports, and associating a first phase tracking radio signal (PTRS) port with the said first DMRS port, further including the said transmission further including a PTRS sent using the said first PTRS port, the method according to claim 13.

20. Determining the first DMRS port based on the MCS value includes determining the first DMRS port based on the MCS value being the highest MCS value associated with the said first one or more DMRS ports or the said second one or more DMRS ports, the method according to claim 19.

21. The DCI according to claim 19 includes information indicating the said first PTRS port.

22. Associating a first PTRS port with a first DMRS port mapped to the said first antenna group further associating a second PTRS port with a second DMRS port mapped to the second antenna group wherein the transmission further comprises a first PTRS sent using the first PTRS port and a second PTRS sent using the second PTRS port, the method of claim 15 **Claim 23** The method of claim 22, wherein the DCI includes information indicating a plurality of PTRS ports **Claim 24** The method of claim 13, wherein the transmission further comprises a physical uplink shared channel (PUSCH) transmission **Claim 25** A processor, receiving, from a wireless transmit / receive unit (WTRU), information associated with at least one coherence capability or antenna layout scheduling a transmission based on the information associated with at least one coherence capability or antenna layout, and determining information associating DMRS ports with CDM groups a computing system comprising a processor configured to schedule the transmission and send the information associating the DMRS ports with the CDM groups to the WTRU **Claim 26** The computing system of claim 25, wherein the information associated with at least one of the coherence capability or antenna layout includes information identifying one or more coherent antenna groups **Claim 27** The computing system of claim 26, wherein the information identifying one or more coherent antenna groups includes information identifying the number of antenna groups **Claim 28** The computing system of claim 25, wherein the information scheduling the transmission and associating the DMRS ports with the CDM groups includes downlink control information (DCI) **Claim 29** The computing system of claim 25, wherein the transmission is a physical uplink shared channel (PUSCH) transmission **Claim 30** The computing system of claim 25, wherein the computing system is a base station **Claim 31** receiving, from a wireless transmit / receive unit (WTRU), information associated with at least one coherence capability or antenna layout Schedule transmissions based on said information associated with at least one coherence capability or antenna layout and determine information associating DMRS ports with CDM groups; A method comprising: scheduling said transmissions and sending said information associating DMRS ports with CDM groups to said WTRU. **Claim 32** The method according to claim 31, wherein said information associated with at least one of a coherence capability or an antenna layout includes information identifying one or more coherent antenna groups. **Claim 33** The method according to claim 32, wherein said information identifying one or more coherent antenna groups includes information identifying the number of antenna groups. **Claim 34** The method according to claim 31, wherein said information scheduling said transmissions and associating DMRS ports with CDM groups includes downlink control information (DCI). **Claim 35** The method according to claim 31, wherein said transmission is a physical uplink shared channel (PUSCH) transmission.

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