Design of demodulation reference signal for large subcarrier spacing

Abstract

Various aspects of the present disclosure generally relate to wireless communications. In some aspects, a user equipment may receive a demodulation reference signal (DMRS) configuration indicating a code division multiplexing (CDM) group configured for a UE; receive a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving a first DMRS transmission set; receive a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and perform channel estimation based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set for the other antenna port exists. Numerous other aspects are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 008,218, filed on April 10, 2020, entitled “DEMODULATION REFERENCE SIGNAL DESIGN FOR LARGE SUB-CARRIER SPACING,” and U.S. Non-Provisional Patent Application No. 17 / 172,836, filed on February 10, 2021, entitled “DEMODULATION REFERENCE SIGNAL DESIGN FOR LARGE SUB-CARRIER SPACING,” which are hereby expressly incorporated herein by reference.

[0003] public domain

[0004] Aspects of the present disclosure relate generally to wireless communications and to techniques and apparatus for demodulation reference signal design for large subcarrier spacing.

[0005] background

[0006] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0007] A wireless communication network may include several base stations (BSs) capable of supporting communications for several user equipment (UEs). UEs may communicate with a BS via downlinks and uplinks. The downlink (or forward link) refers to the communication link from the BS to the UE, while the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in greater detail herein, a BS may be referred to as a Node B, gNB, access point (AP), radio head, transmit / receive point (TRP), new radio (NR) BS, 5G Node B, and so on.

[0008] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate at the city, country, region, and even global levels. NR (which may also be referred to as 5G) is an enhancement set to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with a cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technology and carrier aggregation to improve spectrum efficiency, reduce costs, improve services, utilize new spectrum, and better integrate with other open standards. However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to LTE and NR technologies. Preferably, these improvements should be applicable to other multiple access technologies and telecommunication standards that adopt these technologies.

[0009] Overview

[0010] In some aspects, a wireless communication method performed by a user equipment (UE) may include: receiving a demodulation reference signal (DMRS) configuration, the DMRS configuration indicating a code division multiplexing (CDM) group configured for the UE; receiving a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and performing channel estimation based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set for the other antenna port exists.

[0011] In some aspects, a wireless communication method performed by a base station may include: transmitting a DMRS configuration indicating a CDM group configured for a UE; transmitting a first indication of an antenna port included in the CDM group, which antenna port is assigned to the UE for receiving a first DMRS transmission set; transmitting a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and transmitting the first DMRS transmission set based at least in part on the first indication and the second indication.

[0012] In some aspects, a wireless communication method performed by a user equipment may include: receiving a DMRS configuration indicating a first CDM group and a second CDM group configured for the UE; receiving an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and performing channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0013] In some aspects, a wireless communication method performed by a base station may include: transmitting a DMRS configuration indicating a first CDM group and a second CDM group configured for a UE; transmitting an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and transmitting the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0014] In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: receive a DMRS configuration indicating a CDM group configured for the UE; receive a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving a first DMRS transmission set; receive a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and perform channel estimation based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set for the other antenna port exists.

[0015] In some aspects, a base station for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: transmit a DMRS configuration indicating a CDM group configured for a UE; transmit a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving a first DMRS transmission set; transmit a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and transmit the first DMRS transmission set based at least in part on the first indication and the second indication.

[0016] In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: receive a DMRS configuration indicating a first CDM group and a second CDM group configured for the UE; receive an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and perform channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0017] In some aspects, a base station for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: transmit a DMRS configuration indicating a first CDM group and a second CDM group configured for a UE; transmit an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and transmit the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0018] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to: receive a DMRS configuration indicating a CDM group configured for the UE; receive a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving a first DMRS transmission set; receive a second indication of whether a second DMRS transmission set exists for another antenna port included in the CDM group for another UE; and perform channel estimation based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set exists for the other antenna port.

[0019] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a base station, the one or more instructions may cause the one or more processors to: transmit a DMRS configuration indicating a CDM group configured for a UE; transmit a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving a first DMRS transmission set; transmit a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and transmit the first DMRS transmission set based at least in part on the first indication and the second indication.

[0020] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a UE, the one or more instructions may cause the one or more processors to: receive a DMRS configuration indicating a first CDM group and a second CDM group configured for the UE; receive an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and perform channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0021] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a base station, the one or more instructions may cause the one or more processors to: transmit a DMRS configuration indicating a first CDM group and a second CDM group configured for a UE; transmit an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and transmit the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0022] In some aspects, a device for wireless communication may include: a device for receiving a DMRS configuration indicating a CDM group configured for the device; a device for receiving a first indication of an antenna port included in the CDM group, the antenna port being assigned to the device for receiving a first DMRS transmission set; a device for receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another device; and a device for performing channel estimation based at least in part on the first indication of the antenna port and the second indication of whether a second DMRS transmission set for the other antenna port exists.

[0023] In some aspects, an apparatus for wireless communication may include: a device for transmitting a DMRS configuration indicating a CDM group configured for a UE; a device for transmitting a first indication of an antenna port included in the CDM group, which antenna port is assigned to the UE for receiving a first DMRS transmission set; a device for transmitting a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and a device for transmitting the first DMRS transmission set based at least in part on the first indication and the second indication.

[0024] In some aspects, a device for wireless communication may include: a device for receiving a DMRS configuration indicating a first CDM group and a second CDM group configured for the device; a device for receiving an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and a device for performing channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0025] In some aspects, an apparatus for wireless communication may include: a device for transmitting a DMRS configuration indicating a first CDM group and a second CDM group configured for a UE; a device for transmitting an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and a device for transmitting the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0026] Aspects generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and / or processing systems substantially as described herein with reference to and as illustrated in the accompanying figures and description.

[0027] The foregoing has broadly outlined the features and technical advantages of examples according to the present disclosure in an effort to make the following detailed description better understood. Additional features and advantages will be described hereinafter. The concepts and specific examples disclosed can be readily used as a basis for modifying or designing other structures for implementing the same purposes as the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, both in terms of their organization and method of operation, as well as the associated advantages, will be better understood by considering the following description in conjunction with the accompanying drawings. Each of the figures is provided for illustration and description purposes and is not intended to define limitations on the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to understand in detail the features of the present disclosure set forth above, a more particular description of the content briefly summarized above may be obtained with reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain typical aspects of the present disclosure and are not to be considered limiting of its scope, as the description may admit to other equally effective aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0030] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network according to the present disclosure.

[0031] Figure 2 is a block diagram conceptually illustrating an example of a base station and a UE in communication in a wireless communication network according to the present disclosure.

[0032] Figure 3 is a diagram illustrating an example of an antenna port according to the present disclosure.

[0033] Figure 4 are diagrams illustrating two examples of forming virtual antenna ports by combining incoherent and / or partially coherent antenna ports according to the present disclosure.

[0034] Figures 5 to 7 are diagrams illustrating examples of code division multiplexing (CDM) groups according to the present disclosure.

[0035] Figures 8 to 17 is a diagram illustrating an example associated with a demodulation reference signal (DMRS) design for large subcarrier spacing according to the present disclosure.

[0036] Figures 18 to 21is a diagram illustrating an example procedure related to DMRS design for large subcarrier spacing according to the present disclosure.

[0037] Detailed description

[0038] The various aspects of the present disclosure are described more fully below with reference to the accompanying drawings. However, the present disclosure can be implemented in many different forms and should not be interpreted as being limited to any specific structure or function given throughout the present disclosure. On the contrary, these aspects are provided to make the present disclosure thorough and complete, and they will fully convey the scope of the present disclosure to those skilled in the art. Based on the teachings herein, those skilled in the art will appreciate that the scope of the present disclosure is intended to cover any aspect of the present disclosure disclosed herein, whether it is implemented independently of any other aspect of the present disclosure or implemented in combination. For example, any number of aspects set forth herein can be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods that are practiced using a supplement to the various aspects of the present disclosure set forth herein or other other structures, functionality, or structure and functionality. It should be understood that any aspect of the present disclosure disclosed herein can be implemented by one or more elements of the claims.

[0039] Several aspects of telecommunications systems will now be presented with reference to various devices and techniques. These devices and techniques are described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using hardware, software, or a combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0040] It should be noted that although various aspects may be described herein using terminology generally associated with 3G and / or 4G wireless technologies, various aspects of the present disclosure may be applicable in communication systems based on other generations, such as 5G and later generations, including NR technology.

[0041] Figure 11 is a diagram illustrating a wireless network 100 in which various aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include several BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with user equipment (UE) and may also be referred to as a base station, NR BS, Node B, gNB, 5G Node B (NB), access point, transmit reception point (TRP), etc. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to the coverage area of ​​a BS and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0042] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown in FIG, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB," "base station," "NR BS," "gNB," "TRP," "AP," "Node B," "5G NB," and "cell" may be used interchangeably herein.

[0043] In some aspects, the cells may not necessarily be stationary, and the geographic area of ​​the cells may move depending on the location of the mobile BS. In some aspects, the BSs may interconnect with each other and / or with one or more other BSs or network nodes (not shown) in the wireless network 100 via various types of backhaul interfaces (such as direct physical connections, virtual networks, etc.) using any suitable transport network.

[0044] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and send transmissions of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown in , relay station 110d may communicate with macro BS 110a and UE 120d to facilitate communication between BS 110a and UE 120d. A relay station may also be referred to as a relay BS, relay base station, relay, or the like.

[0045] The wireless network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 to 2 watts).

[0046] The network controller 130 may be coupled to a set of BSs and may provide coordination and control of these BSs. The network controller 130 may communicate with each BS via a backhaul. These BSs may also communicate with each other directly or indirectly, for example, via a wireless or wired backhaul.

[0047] UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. A UE may be a cellular phone (e.g., a smartphone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biometric sensor / device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[0048] Some UEs may be considered machine type communication (MTC) UEs, or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, and the like, which may communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity to or to a network (e.g., a wide area network (such as the Internet) or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices and / or may be implemented as NB-IoT (Narrowband Internet of Things) devices. Some UEs may be considered customer premises equipment (CPE). UE 120 may be included within a housing that houses components of UE 120, such as a processor component, a memory component, and the like. In some aspects, the processor component and the memory component may be coupled together. For example, the processor component (e.g., one or more processors) and the memory component (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled, electrically coupled, and the like.

[0049] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, frequency channel, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

[0050] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary) using one or more sidelink channels. For example, the UEs 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocols (e.g., which may include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, etc.), mesh networks, etc. In this scenario, the UEs 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by the base station 110.

[0051] As indicated above, Figure 1 are provided as examples. Other examples may differ from those described in Figure 1 The example depicted.

[0052] Figure 2 A block diagram shows a design 200 of a base station 110 and a UE 120, which may be Figure 1 One for each base station and one for each UE in . Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T≧1 and R≧1.

[0053] At base station 110, transmit processor 220 may receive data for one or more UEs from data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS)) and synchronization signals (e.g., a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)). A transmit (TX) multiple-input, multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, as applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and frequency upconvert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively. According to various aspects described in greater detail below, position coding may be utilized to generate synchronization signals to convey additional information.

[0054] At UE 120, antennas 252a through 252r may receive downlink signals from base station 110 and / or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. The channel processor may determine reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), channel quality indicator (CQI), etc. In some aspects, one or more components of UE 120 may be included in a housing.

[0055] On the uplink, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.) from a controller / processor 280. The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266, if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by MIMO detector 236, if applicable, and further processed by a receive processor 238 to obtain decoded data and control information transmitted by the UE 120. Receive processor 238 may provide decoded data to data sink 239 and decoded control information to controller / processor 240. Base station 110 may include communication unit 244 and communicate with network controller 130 via communication unit 244. Network controller 130 may include communication unit 294, controller / processor 290, and memory 292.

[0056] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2Any other component(s) of the base station 110 may perform one or more techniques associated with demodulation reference signal design for large subcarrier spacing, as described in more detail elsewhere herein. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component of the may perform or direct e.g. Figure 18 The process of 1800 Figure 19 The process of 1900, Figure 20 The process of 2000, Figure 21 2100, and / or operations of other processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compilation, conversion, interpretation, etc.) by one or more processors of base station 110 and / or UE 120, may perform or direct, for example, Figure 18 The process of 1800 Figure 19 The process of 1900, Figure 20 The process of 2000, Figure 21 The process 2100 of , and / or operations of other processes as described herein. In some aspects, executing instructions may include running instructions, converting instructions, compiling instructions, interpreting instructions, etc. The scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0057] In some aspects, UE 120 may include: a device for receiving a demodulation reference signal (DMRS) configuration, the DMRS configuration indicating a code division multiplexing (CDM) group configured for the UE; a device for receiving a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; a device for receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; a device for performing channel estimation based at least in part on the first indication of the antenna port and the second indication of whether a second DMRS transmission set for the other antenna port exists; and the like. Additionally or alternatively, UE 120 may include: means for receiving a DMRS configuration indicating a first CDM group and a second CDM group configured for the UE; means for receiving an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for use in a DMRS transmission set; means for performing channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined; and the like. In some aspects, such means may include in conjunction with Figure 2 One or more components of the UE 120 are depicted, such as the controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, and so forth.

[0058] In some aspects, the base station 110 may include: means for transmitting a DMRS configuration indicating a CDM group configured for a UE; means for transmitting a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; means for transmitting a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; means for transmitting the first DMRS transmission set based at least in part on the first indication and the second indication; and so on. Additionally or alternatively, the base station 110 may include: means for transmitting a DMRS configuration indicating a first CDM group and a second CDM group configured for the UE; means for transmitting an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for the DMRS transmission set; means for transmitting the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined; and so on. In some aspects, such means may include means for transmitting a DMRS configuration in combination with Figure 2One or more components of base station 110 are depicted, such as antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, and so forth.

[0059] As indicated above, Figure 2 are provided as examples. Other examples may differ from those described in Figure 2 The example depicted.

[0060] Figure 3 is a diagram illustrating an example 300 of antenna ports in accordance with various aspects of the present disclosure.

[0061] like Figure 3 As shown in , the first physical antenna 305-1 can transmit information via a first channel h1, the second physical antenna 305-2 can transmit information via a second channel h2, the third physical antenna 305-3 can transmit information via a third channel h3, and the fourth physical antenna 305-4 can transmit information via a fourth channel h4. Such information can be conveyed via a logical antenna port, which can represent some combination of physical antennas and / or channels. In some cases, the UE 120 may not be aware of the channels associated with the physical antennas and may operate based solely on knowledge of the channels associated with the antenna ports, as defined below.

[0062] An antenna port can be defined such that the channel over which a symbol is transmitted on that antenna port can be inferred from the channel over which another symbol is transmitted on the same antenna port. In example 300, the channel associated with antenna port 1 (AP1) is represented as h1-h2+h3+j*h4, where the channel coefficients (e.g., 1, -1, 1, and j in this case) represent weighting factors (e.g., indicating phase and / or gain) applied to each channel. Such weighting factors can be applied to the channels to improve signal power and / or signal quality at one or more receivers. Applying such weighting factors to channel transmissions can be referred to as precoding, and a particular set of weighting factors applied to a set of channels can be referred to as a precoder.

[0063] Similarly, the channel associated with antenna port 2 (AP2) is represented as h1+j*h3, and the channel associated with antenna port 3 (AP3) is represented as 2*h1-h2+(1+j)*h3+j*h4. In this case, antenna port 3 can be represented as the sum of antenna port 1 and antenna port 2 (e.g., AP3=AP1+AP2) because the sum of the expression representing antenna port 1 (h1-h2+h3+j*h4) and the expression representing antenna port 2 (h1+j*h3) equals the expression representing antenna port 3 (2*h1-h2+(1+j)*h3+j*h4). Antenna port 3 can also be said to be related to antenna port 1 and antenna port 2 (AP1, AP2) via precoder [1, 1] because 1 times the expression representing antenna port 1 plus 1 times the expression representing antenna port 2 equals the expression representing antenna port 3.

[0064] As indicated above, Figure 3 These are provided as examples only. Other examples may differ from those regarding Figure 3 The example depicted.

[0065] Figure 4 is a diagram illustrating two examples 400 of forming virtual antenna ports by combining incoherent and / or partially coherent antenna ports in accordance with various aspects of the present disclosure.

[0066] The antennas of a multi-antenna UE (e.g., UE 120) can be classified into one of three groups depending on the coherence of the UE's antenna ports. A set of antenna ports (e.g., two antenna ports) is coherent if the relative phase between them remains the same between the time of an SRS transmission from those antenna ports and the time of a subsequent physical uplink shared channel (PUSCH) transmission from those antenna ports. In this case, since the relative phase of the antenna ports will be the same for SRS and PUSCH transmissions, the SRS can be used (e.g., by the UE or BS) to determine the uplink precoder used to precode the PUSCH transmission. The precoding can span the coherent antenna port set.

[0067] If the antenna port set is non-coherent, such uplink precoder determination becomes difficult because the relative phase between the antenna ports will change from SRS transmission to PUSCH transmission. For example, if the relative phase between the antenna port set is different for SRS transmission and PUSCH transmission, the antenna port set is considered non-coherent. In this case, using the same uplink precoder for the non-coherent antenna port set may cause the UE to apply incorrect or inaccurate precoding weights (such as phase and gain weights) to the data streams transmitted from the non-coherent antenna ports. In addition, if a first subset of the antenna port set is coherent with each other and a second subset of the antenna port set is coherent with each other, but the first antenna port subset and the second antenna port subset are incoherent with each other, the antenna port set is considered partially coherent. In this case, a common precoder may be used within each of the corresponding subsets of coherent antenna ports, but not across different subsets of non-coherent antenna ports.

[0068] In some cases, when a BS schedules PUSCH transmission for a multi-antenna UE with non-coherent or partially coherent antenna ports, the signaling communication scheduling the PUSCH transmission may identify the uplink precoder to be used for precoding the PUSCH transmission. Conventionally, because the UE's antenna ports are non-coherent (or, in the case of partially coherent antenna ports, a non-coherent group of coherent antenna ports), the UE may be able to use an uplink precoder for only one of the antenna ports (or antenna port groups), while the other antenna ports (or antenna port groups) are not used for PUSCH transmission. Due to the use of only a subset of non-coherent or partially coherent antenna ports, this may result in reduced transmit power for PUSCH transmission, reduced reliability of PUSCH transmission (due to lack of transmit or spatial diversity), etc.

[0069] To utilize some or all of the non-coherent or partially coherent antenna ports, the UE may apply various techniques to combine the non-coherent or partially coherent antenna ports into virtual antenna ports, so that a common precoding can be used on the virtual antenna ports and applied across the non-coherent antenna ports. A virtual (or logical) antenna port may represent a combination of two or more antenna ports. This allows the BS to select an uplink precoder for the virtual antenna port and allows the UE to transmit using the uplink precoder on the non-coherent or partially coherent antenna ports that have been combined to form the virtual antenna port.

[0070] For example, as shown in reference numeral 405, precoding (e.g., uplink precoding) and cyclic delay diversity can be used to combine a set of non-coherent antenna ports (e.g., shown as two non-coherent antenna ports) into a single virtual port. The precoder can be determined by the UE 120 and / or signaled by the base station 110. Cyclic delay diversity (CDD) can refer to a technique that introduces a delay (e.g., a cyclic delay) on one of the non-coherent antenna ports but not on the other non-coherent antenna ports. The delay can be measured in samples (e.g., 5 samples, 10 samples, etc.), sample fractions, etc. For example, a first non-coherent antenna port can transmit a first sample stream, while a second non-coherent antenna port can transmit a second sample stream (e.g., which can be the same stream) with a slight cyclic delay (e.g., a delay of 5 samples, 10 samples, etc.). For example, for a cyclic delay of 5 samples, in the case of transmitting 16 samples per codeword, the first non-coherent antenna port may transmit 16 samples, where the first sample is transmitted first (e.g., [s1, s2, s3, s4, ..., s16]), and the second non-coherent antenna port may transmit 16 samples, where the first sample is transmitted sixth (e.g., with a delay of five samples) (e.g., [s12, s13, s14, s15, s16, s1, s2, s3, ..., s11]).

[0071] Additionally or alternatively, as shown by reference numeral 410, precoding (e.g., uplink precoding) and cyclic delay diversity can be used in a similar manner as described above to combine a set of partially coherent antenna ports into a single virtual antenna port. As shown, a first subset of antenna ports can be coherent with each other, and a second subset of antenna ports can be coherent with each other, but the two subsets can be incoherent with each other. As further shown, precoding can be applied to the individual subsets to generate a first virtual antenna port and a second virtual antenna port that are incoherent with each other. CDD can then be applied to the two virtual antenna ports (e.g., by using CDD to transmit communications from the virtual antenna ports), thereby forming a single virtual antenna port from the partially coherent antenna ports (e.g., using precoding and CDD).

[0072] although Figure 4 Antenna port pairs are shown in sets and subsets, but in some aspects, a different number of antenna ports may be included in a set or subset. For example, an antenna port set or antenna port subset may include three antenna ports, four antenna ports, etc.

[0073] As indicated above, Figure 4 is provided as one or more examples. Other examples are possible and may differ from the examples described herein. Figure 4 Examples described.

[0074] Figure 5is a diagram illustrating an example 500 of a code division multiplexing (CDM) group according to various aspects of the present disclosure. In a wireless communication system, multiple demodulation reference signal (DMRS) ports can be used to transmit on the same orthogonal frequency division multiplexing (OFDM) symbol using CDM and frequency division multiplexing (FDM). Using FDM, different DMRS ports can be used to transmit DMRS on the same OFDM symbol by using different subcarriers (e.g., frequency tones) for different DMRS ports. Using CDM, different DMRS ports can be used to transmit DMRS on the same OFDM symbol (or across a set of OFDM symbols on the same subcarrier) by using different orthogonal cover codes (OCCs) for different DMRS ports. DMRS ports used for transmission on the same subcarrier belong to the same CDM group, and DMRS ports used for transmission on different subcarriers belong to different CDM groups. In other words, a CDM group includes a set of DMRS ports used to transmit corresponding DMRS sets on the same subcarrier, wherein different OCCs are used for (eg, scramble) transmissions on different DMRS ports included in the DMRS port set.

[0075] The maximum number of CDM groups supported by a symbol may depend on the DMRS configuration of the symbol (or the resource block that includes the symbol). The DMRS configuration may specify the maximum number of DMRS ports that may be used for DMRS transmission on a single symbol. As an example, and as indicated by reference numeral 505, a first type of DMRS configuration (e.g., DMRS configuration type 1) may support a maximum of two CDM groups per symbol. In this configuration, a first CDM group (shown as CDM group 0) may occupy a first set of subcarriers (such as even subcarriers) on a symbol, and a second CDM group (shown as CDM group 1) may occupy a second set of subcarriers (such as odd subcarriers) on the symbol. As another example, and as indicated by reference numeral 510, a second type of DMRS configuration (e.g., DMRS configuration type 2) may support a maximum of three CDM groups per symbol. In this configuration, a first CDM group (shown as CDM group 0) may occupy a first set of subcarriers on a symbol (shown as subcarriers 0, 1, 6, and 7), a second CDM group (shown as CDM group 1) may occupy a second set of subcarriers on the symbol (shown as subcarriers 2, 3, 8, and 9), and a third CDM group (shown as CDM group 2) may occupy a third set of subcarriers on the symbol (shown as subcarriers 4, 5, 10, and 11). Figure 6 and Figure 7 Additional details of CDM groups are described.

[0076] As indicated above, Figure 5 are provided as examples. Other examples may differ from those described in Figure 5 Examples described.

[0077] Figure 6 is a diagram illustrating an example 600 of a CDM group according to aspects of the present disclosure. Figure 5 As depicted in reference numeral 505, a first type of DMRS configuration (e.g., DMRS configuration type 1) may support a maximum of two CDM groups per symbol. In this configuration, a first CDM group (CDM group 0) may occupy a first set of subcarriers (such as even subcarriers) on a symbol, and a second CDM group (CDM group 1) may occupy a second set of subcarriers (such as odd subcarriers) on the symbol.

[0078] As shown by reference numeral 605, in some aspects, the DMRS configuration indicating the first type of DMRS configuration may also indicate that the DMRS is transmitted on one OFDM symbol (shown as symbol 2). In this case, the first CDM group (which occupies even subcarriers in this example) includes DMRS port 1000 and DMRS port 1001, and the second CDM group (which occupies odd subcarriers in this example) includes DMRS port 1002 and DMRS port 1003. The + and - characters shown in the figures represent the OCC applied to the DMRS transmission or DMRS sequence in a particular resource element, where the OCC represented by the + character is different from the OCC represented by the - character. A DMRS port can sometimes be referred to by one or more least significant bits of the DMRS port identifier. For example, DMRS port 1000 may be referred to as DMRS port 0, DMRS port 1001 may be referred to as DMRS port 1, DMRS port 1002 may be referred to as DMRS port 2, DMRS port 1003 may be referred to as DMRS port 3, DMRS port 1010 may be referred to as DMRS port 10, DMRS port 1011 may be referred to as DMRS port 11, and so on.

[0079] As shown by reference numeral 610, in some aspects, the DMRS configuration indicating the first type of DMRS configuration may also indicate that the DMRS is transmitted on two OFDM symbols (shown as symbols 2 and 3). In this case, the first CDM group (which occupies even subcarriers in this example) includes DMRS port 1000, DMRS port 1001, DMRS port 1004, and DMRS port 1005. In addition, the second CDM group (which occupies odd subcarriers in this example) includes DMRS port 1002, DMRS port 1003, DMRS port 1006, and DMRS port 1007.

[0080] As indicated above, Figure 6 are provided as examples. Other examples may differ from those described in Figure 6 Examples described.

[0081] Figure 7 is a diagram illustrating an example 700 of a CDM group according to aspects of the present disclosure. Figure 5 As depicted by reference numeral 510, a second type of DMRS configuration (e.g., DMRS configuration type 2) may support a maximum of three CDM groups per symbol. In this configuration, a first CDM group (CDM group 0) may occupy a first set of subcarriers on a symbol (shown as subcarriers 0, 1, 6, and 7), a second CDM group (CDM group 1) may occupy a second set of subcarriers on the symbol (shown as subcarriers 2, 3, 8, and 9), and a third CDM group (CDM group 2) may occupy a third set of subcarriers on the symbol (shown as subcarriers 4, 5, 10, and 11).

[0082] As shown by reference numeral 705, in some aspects, the DMRS configuration indicating the second type of DMRS configuration may also indicate that the DMRS is transmitted on one OFDM symbol (shown as symbol 2). In this case, the first CDM group includes DMRS port 1000 and DMRS port 1001, the second CDM group includes DMRS port 1002 and DMRS port 1003, and the third CDM group includes DMRS port 1004 and DMRS port 1005.

[0083] As shown by reference numeral 710, in some aspects, the DMRS configuration indicating the second type of DMRS configuration may also indicate that the DMRS is transmitted on two OFDM symbols (shown as symbols 2 and 3). In this case, the first CDM group includes DMRS port 1000, DMRS port 1001, DMRS port 1006, and DMRS port 1007, the second CDM group includes DMRS port 1002, DMRS port 1003, DMRS port 1008, and DMRS port 1009, and the third CDM group includes DMRS port 1004, DMRS port 1005, DMRS port 1010, and DMRS port 1011.

[0084] For wireless communications in sub-6 GHz bands (such as frequency range 1 (FR1)) and in millimeter wave bands (such as FR2), combined Figures 5 to 7The described DMRS design can permit relatively accurate channel estimation and / or interpolation for subcarriers on which DMRS is not received. For example, a UE receiving a DMRS transmission on port 0 among even subcarriers for a first type of DMRS configuration can use DMRS measurements to estimate and / or interpolate channels on odd subcarriers, even though no DMRS transmission is received on the odd subcarriers. Similarly, a UE receiving a DMRS transmission on port 0 among subcarriers 0, 1, 6, and 7 for a second type of DMRS configuration can use DMRS measurements to estimate and / or interpolate channels on subcarriers 2 to 5 and 8 to 11, even though no DMRS transmission is received on those subcarriers.

[0085] However, for wireless communications in higher frequency bands (e.g., greater than 52.6 GHz, up to 71 GHz, etc.), a larger subcarrier spacing (e.g., 960 kHz, 1.92 MHz, 3.84 MHz, etc.) may be used compared to lower frequency bands (such as FR1 and FR2, which may use subcarrier spacing of 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc.), using the same Fast Fourier Transform (FFT) size as the lower frequency bands. Larger subcarrier spacing may mitigate the effects of phase noise in the higher frequency bands and may support larger bandwidths (such as 2 GHz) using reasonable FFT sizes. However, with larger subcarrier spacing, combined with Figures 5 to 7 The described DMRS design may not allow accurate channel estimation and / or interpolation for subcarriers on which no DMRS is received because the spacing between subcarriers (e.g., coherence bandwidth) is larger and therefore more difficult to accurately estimate and / or interpolate across subcarriers. Some techniques and devices described herein enable more accurate channel estimation and / or interpolation for this larger subcarrier spacing.

[0086] As indicated above, Figure 7 are provided as examples. Other examples may differ from those described in Figure 7 Examples described.

[0087] Figure 8 is a diagram illustrating an example 800 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 8 As shown in , base station 110 and UE 120 may communicate with each other.

[0088] As shown by reference numeral 805, base station 110 may transmit a DMRS configuration to UE 120. The DMRS configuration may be included in a configuration message, such as a radio resource control (RRC) message. As shown, the DMRS configuration may indicate one or more CDM groups configured for UE 120, and corresponding DMRS ports included in each CDM group. In example 800, the DMRS configuration indicates a first CDM group (CDM group 0) including DMRS port 0 and DMRS port 1, and further indicates a second CDM group (CDM group 1) including DMRS port 2 and DMRS port 3.

[0089] As shown by reference numeral 810, base station 110 may transmit an indication (e.g., a first indication) of an antenna port included in the CDM group to UE 120, the antenna port being assigned to UE 120 for receiving a first set of DMRS transmissions. This antenna port (e.g., DMRS port) may be referred to as an assigned DMRS port, a scheduled DMRS port, etc. UE 120 may use the indicated port to receive DMRS transmissions transmitted by base station 110. As shown, the DMRS port may be included in one of the CDM groups configured for UE 120. In example 800, the assigned DMRS port is DMRS port 0, which is included in CDM group 0 and includes a single multiple-input multiple-output (MIMO) layer.

[0090] In some aspects, the indicated port for receiving a DMRS transmission may be assigned to UE 120 for one or more resource blocks (RBs). For example, the indicated DMRS port may be used to receive a DMRS transmission in a set of RBs included in a resource allocation scheduled for UE 120 (e.g., for one or more physical downlink shared channel (PDSCH) communications). In some aspects, the DMRS port, RB set, resource allocation, etc. may be indicated in downlink control information (DCI).

[0091] As indicated by reference numeral 815, the base station 110 may transmit to the UE 120 a second DMRS transmission set for another antenna port included in the CDM group (eg, different from Figure 8In example 800, DMRS port 0 and DMRS port 1 are included in CDM group 0, DMRS port 0 is assigned to UE 120, and the second indication indicates that there is no DMRS transmission on DMRS port 1 (which is included in the same CDM group as DMRS port 0). In some aspects, the second indication can be included in a configuration message (e.g., an RRC message), in a DCI, in an activation DCI, in a media access control (MAC) control element (MAC-CE), and the like. In some aspects, the present invention relates to Figures 8 to 11 The described techniques and operations may be used for single-layer communications (eg, using a single port for DMRS transmission from the base station 110 to the UE 120 ).

[0092] In some aspects, the second indication may be included in the DCI. In some aspects, the first indication and the second indication may be included in the same message, such as the same DCI message. In some aspects, the first indication and the second indication are indicated using the same field in the DCI. In some aspects, the first indication and the second indication are indicated using a single value (e.g., an index value) in the DCI. In some aspects, the single value in the DCI indicates the number of CDM groups with no data, the antenna port assigned to the UE 120, and whether a second DMRS transmission set for another antenna port exists for another UE 120. In some aspects, the first field in the DCI includes the first indication, and the second field in the DCI includes the second indication. In some aspects, the second field includes a single bit. In some cases, including the second indication in the DCI message can provide the base station 110 with greater scheduling flexibility than signaling the second indication in the RRC message. The following is combined with Figure 9 and Figure 10 Additional details of these aspects based on DCI are described.

[0093] In some aspects, the second indication may be included in a configuration message. In some aspects, the DMRS configuration and the second indication may be included in the same message, such as the same configuration message (e.g., the same RRC message). As used herein, an RRC message may include an RRC configuration message, an RRC reconfiguration message, and the like. In some cases, including the second indication in the RRC message may save signaling overhead compared to signaling the second indication in multiple different DCI messages over time. In some aspects, a DMRS table (e.g., a DMRS antenna port table) including at least one of the first indication or the second indication indicated in the DMRS configuration is different for a UE 120 compared to another UE 120, as described below in conjunction with Figure 11 Described in more detail.

[0094] In some aspects, the second indication may be based at least in part on a modulation and coding scheme (MCS) signaled by the base station 110 to the UE 120 in association with the first indication of the antenna port assigned to the UE 120. For example, a DCI indicating a DMRS port assigned to the UE 120 may also indicate an MCS to be used for communications (e.g., data communications, such as PDSCH communications) scheduled by the DCI (and for which channel estimation using DMRS is performed). The MCS (e.g., MCS index value, modulation scheme, coding scheme, etc.) may specify whether a DMRS transmission is present on a non-assigned DMRS port (e.g., non-assigned DMRS port 1 in example 800) from the same CDM group as the assigned DMRS port.

[0095] For example, if the MCS index signaled to UE 120 meets a threshold (e.g., is greater than a threshold, is greater than or equal to a threshold, etc.), UE 120 may determine that DMRS transmissions on non-assigned DMRS ports from the same CDM group as the assigned DMRS port do not exist, because the performance of higher MCSs is more sensitive to channel estimation errors. As another example, if the MCS index signaled to UE 120 does not meet the threshold (e.g., is less than the threshold, is less than or equal to the threshold, etc.), UE 120 may determine that DMRS transmissions on non-assigned DMRS ports from the same CDM group as the assigned DMRS port exist (e.g., for single-layer MIMO), because the performance of lower MCSs is less sensitive to channel estimation errors. For multi-layer MIMO, if UE 120 is scheduled using two codewords, UE 120 may assume that all remaining orthogonal antenna ports are not associated with transmitting a PDSCH to another UE, and therefore, may assume that DMRS transmissions on non-assigned DMRS ports from the same CDM group as the assigned DMRS port do not exist.

[0096] Additionally or alternatively, the second indication may be based at least in part on a subcarrier spacing and / or an estimated delay spread associated with the UE 120 and the base station 110. For example, the second indication may be based at least in part on a subcarrier spacing configured and / or used for communications between the UE 120 and the base station. In some aspects, the subcarrier spacing and / or the estimated delay spread may specify whether a DMRS transmission is present on a non-assigned DMRS port (e.g., non-assigned DMRS port 1 in example 800) from the same CDM group as the assigned DMRS port, similar to the MCS example described above.

[0097] For example, if the subcarrier spacing and / or the estimated delay spread satisfies a threshold (e.g., is greater than a threshold, is greater than or equal to a threshold, etc.), UE 120 may determine that DMRS transmission on a non-assigned DMRS port from the same CDM group as the assigned DMRS port is not present, because communications with large subcarrier spacing and large delay spread are more sensitive to channel estimation errors. As another example, if the subcarrier spacing and / or the estimated delay spread does not satisfy the threshold (e.g., is less than the threshold, is less than or equal to the threshold, etc.), UE 120 may determine that DMRS transmission on a non-assigned DMRS port from the same CDM group as the assigned DMRS port is present (e.g., for single-layer MIMO), because communications with small subcarrier spacing and small delay spread are less sensitive to channel estimation errors. For multi-layer MIMO, if UE 120 is scheduled using two codewords, UE 120 may assume that all remaining orthogonal antenna ports are not associated with transmitting PDSCH to another UE and may therefore assume that DMRS transmissions on non-assigned DMRS ports from the same CDM group as the assigned DMRS ports are absent.

[0098] In some aspects, UE 120 may determine whether DMRS transmission is present based at least in part on whether the MCS satisfies a first threshold, whether the subcarrier spacing satisfies a second threshold, and / or whether the estimated delay spread satisfies a third threshold. In some aspects, base station 110 may indicate one or more of these thresholds (e.g., the first threshold, the second threshold, and / or the third threshold, such as the MCS threshold, the subcarrier spacing threshold, and / or the delay spread threshold) to UE 120, such as in a configuration message, a MAC-CE, etc. In some aspects, one or more of these thresholds may be specified in a wireless communication standard.

[0099] As indicated by reference numeral 820, base station 110 may transmit a DMRS according to the first indication and the second indication. For example, if the second indication indicates that a DMRS transmission is present on DMRS port 1, base station 110 may transmit a first DMRS transmission set to UE 120 on DMRS port 0, and may transmit a second DMRS transmission set to another UE 120 on DMRS port 1. Alternatively, if the second indication indicates that a DMRS transmission is not present on DMRS port 1, base station 110 may transmit the first DMRS transmission set to UE 120 on DMRS port 0, and may refrain from transmitting the second DMRS transmission set to another UE 120 on DMRS port 1.

[0100] As indicated by reference numeral 825, UE 120 may perform channel estimation based at least in part on the first indication and the second indication. For example, if the second indication indicates that a DMRS transmission is present on DMRS port 1, UE 120 may receive a first set of DMRS transmissions on DMRS port 0 (e.g., as indicated by the first indication) and may perform channel estimation using an OCC (sometimes referred to as de-CDMing). In this case, UE 120 may multiply the received DMRS sequence on DMRS port 0 by the associated OCC to obtain an expected DMRS sequence and may then perform DMRS processing on the expected DMRS sequence. Alternatively, if the second indication indicates that a DMRS transmission is not present on DMRS port 1, UE 120 may receive a first set of DMRS transmissions on DMRS port 0 (e.g., as indicated by the first indication) and may perform channel estimation without using an OCC (e.g., without performing de-CDMing). In this case, UE 120 may directly perform DMRS processing on the received DMRS sequence without multiplying the received DMRS sequence by the associated OCC, thereby saving resources of UE 120 (eg, processing resources, memory resources, battery power, etc.).

[0101] As indicated above, Figure 8 are provided as examples. Other examples may differ from those described in Figure 8 Examples described.

[0102] Figure 9 is a diagram illustrating an example 900 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 8 As described, base station 110 may indicate whether a second DMRS transmission set for a DMRS port not assigned to UE 120 and included in the same CDM group as the DMRS port assigned to UE 120 for the first DMRS transmission set exists for another UE 120. In some aspects, this indication may be included in a DCI.

[0103] like Figure 9As shown in , in some aspects, a single value (shown as "value") in the DCI indicates: the number of DMRS CDM groups without data and one or more DMRS ports assigned to the UE 120. As shown by reference numeral 905, in some aspects, a single value may indicate the number of DMRS CDM groups without data, one or more DMRS ports assigned to the UE 120, and whether a second DMRS transmission set for one or more other DMRS ports (included in the same CDM group as the assigned DMRS port(s)) exists for another UE 120. In some aspects, one or more reserved bits of the DCI (e.g., having a legacy DCI format) may be used for this indication. By using a single value to indicate multiple parameters, signaling overhead may be saved. In some aspects, Figure 9 The table shown in (or indicating the combination of Figure 9 A similar table of values ​​described herein may be indicated by base station 110 to UE 120, such as in a configuration message.

[0104] As indicated above, Figure 9 are provided as examples. Other examples may differ from those described in Figure 9 Examples described.

[0105] Figure 10 is a diagram illustrating an example 1000 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 8 As described, base station 110 may indicate whether a second DMRS transmission set for a DMRS port not assigned to UE 120 and included in the same CDM group as the DMRS port assigned to UE 120 for the first DMRS transmission set exists for another UE 120. In some aspects, this indication may be included in a DCI.

[0106] like Figure 10 As shown in , in some aspects, a single value (shown as "value") in the DCI indicates: the number of DMRS CDM groups with no data, one or more DMRS ports assigned to the UE 120, and the number of frontload symbols (e.g., for the DMRS). As shown by reference numeral 1005, in some aspects, a single value may indicate: the number of DMRS CDM groups with no data, one or more DMRS ports assigned to the UE 120, the number of frontload symbols, and whether a second DMRS transmission set for one or more other DMRS ports (included in the same CDM group as the assigned DMRS port(s)) exists for another UE 120.

[0107] In some aspects, the DCI field (e.g., of a DCI with a legacy DCI format) may be extended to have a larger bit length to support this indication. By using a single value to indicate multiple parameters, signaling overhead may be saved. Alternatively, rather than extending the number of bits of this DCI field, a first field in the DCI may indicate the number of DMRS CDM groups with no data, one or more DMRS ports assigned to the UE 120, and / or the number of frontload symbols, and a second field in the DCI may indicate whether a DMRS transmission exists for a non-assigned DMRS port in the same CDM group as the assigned DMRS port. In some aspects, the second field comprises a single bit. In some aspects, Figure 10 The table shown in (or indicating the combination of Figure 10 A similar table of values ​​described herein may be indicated by base station 110 to UE 120, such as in a configuration message.

[0108] As indicated above, Figure 10 are provided as examples. Other examples may differ from those described in Figure 10 Examples described.

[0109] Figure 11 is a diagram illustrating an example 1100 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 11 As shown in , a DMRS table (e.g., a DMRS antenna port table) may include a set of values ​​(shown as entries in the "Value" column). Each value in the set of values ​​may indicate the number of DMRS CDM groups without data, one or more DMRS ports assigned to UE 120, the number of front-load symbols, and / or whether a DMRS transmission exists for a non-assigned DMRS port in the same CDM group as an assigned DMRS port. When a DMRS table (e.g., in combination with Figure 8-11 When any DMRS table shown or described herein is configured for UE 120, UE 120 may reference the DMRS table to determine one or more parameters corresponding to a value signaled to UE 120. For example, the value may be signaled in the DCI, and UE 120 may use the value to look up a corresponding entry in the DMRS table.

[0110] like Figure 11As shown in , in some aspects, a DMRS table 1105 configured for a first UE 120 (e.g., a first DMRS table) can be different from a DMRS table 1110 (e.g., a second DMRS table) configured for a second UE 120. In example 1100, a value of 0 in the DMRS table 1105 for UE 0 indicates that DMRS port 0 is assigned to UE 0 and that there is a DMRS transmission on DMRS port 1 (e.g., in the same CDM group as DMRS port 0), and a value of 1 in the DMRS table 1105 for UE 0 indicates that DMRS port 0 is assigned to UE 0 and that there is no DMRS transmission on DMRS port 1. However, a value of 0 in the DMRS table 1110 for UE 1 indicates that DMRS port 1 is assigned to UE 1 and there is a DMRS transmission on DMRS port 0 (e.g., in the same CDM group as DMRS port 1), and a value of 1 in the DMRS table 1110 for UE 1 indicates that DMRS port 1 is assigned to UE 1 and there is no DMRS transmission on DMRS port 0. In this way, the size of the DCI can be reduced or maintained (e.g., by avoiding adding DCI bits) while providing increased scheduling flexibility for the base station 110.

[0111] As indicated above, Figure 11 are provided as examples. Other examples may differ from those described in Figure 11 Examples described.

[0112] Figure 12 is a diagram illustrating an example 1200 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 12 As shown in , base station 110 and UE 120 may communicate with each other.

[0113] As shown by reference numeral 1205, base station 110 may transmit a DMRS configuration to UE 120. The DMRS configuration may be included in a configuration message, such as an RRC message. As shown, the DMRS configuration may indicate a plurality of CDM groups configured for UE 120, and corresponding DMRS ports included in each CDM group. In example 1200, the DMRS configuration indicates a first CDM group (CDM group 0) including DMRS port 0 and DMRS port 1, and further indicates a second CDM group (CDM group 1) including DMRS port 2 and DMRS port 3.

[0114] As indicated by reference numeral 1210, the base station 110 may transmit to the UE 120 an indication of whether to combine a first antenna port (e.g., a first DMRS port) included in the first CDM group and a second antenna port (e.g., a second DMRS port) included in the second CDM group into a single virtual port for DMRS transmission. In example 1200, the indication indicates whether to combine DMRS port 0 (from CDM group 0) and DMRS port 2 (from CDM group 1) into a single virtual port. As another example, the indication may indicate whether to combine DMRS port 1 (from CDM group 0) and DMRS port 3 (from CDM group 1) into a single virtual port. The details of combining multiple ports into a single virtual port are described above in conjunction with Figure 4 In some aspects, the indication may be included in a configuration message (eg, an RRC message), a DCI, an activation DCI, a MAC-CE, and the like.

[0115] In some aspects, an indication of whether DMRS ports are to be combined and / or which DMRS ports are to be combined can be indicated to UE 120 for one or more resource blocks (RBs). For example, the indicated DMRS ports (e.g., combined into a single virtual port) can be used to receive DMRS transmissions in a set of RBs included in a resource allocation scheduled for UE 120 (e.g., for one or more PDSCH communications). In some aspects, the indication of whether DMRS ports are to be combined, the set of RBs, the resource allocation, etc. can be indicated in a DCI.

[0116] In some aspects, the indication may be included in the DCI. In some aspects, the first DMRS port, the second DMRS port, and an indication of whether the first DMRS port and the second DMRS port are to be combined are indicated using the same field in the DCI. In some aspects, the first DMRS port, the second DMRS port, and an indication of whether the first DMRS port and the second DMRS port are to be combined are indicated using a single value (e.g., an index value) in the DCI. In some aspects, the single value in the DCI indicates: the number of CDM groups without data, the first DMRS port, the second DMRS port, and whether the first DMRS port and the second DMRS port are to be combined into a single virtual port. In some aspects, the first field in the DCI indicates the first DMRS port and the second DMRS port, and the second field in the DCI indicates whether the first DMRS port and the second DMRS port are to be combined into a single virtual port. In some aspects, the second field includes a single bit. In some cases, including the indication in the DCI message can provide greater scheduling flexibility for the base station 110 compared to signaling the indication in the RRC message. The following is combined Figure 13 and Figure 14 Additional details of these aspects based on DCI are described.

[0117] In some aspects, the indication may be included in a configuration message. In some aspects, the DMRS configuration and the indication may be included in the same message, such as the same configuration message (e.g., the same RRC message). In some cases, including the indication in the RRC message may save signaling overhead compared to signaling the indication in multiple different DCI messages over time. In some aspects, the DMRS table (e.g., DMRS antenna port table) indicated in the DMRS configuration, including at least one of the indications, may be different for a UE 120 compared to another UE 120, as described below in conjunction with Figure 15 Described in more detail.

[0118] In some aspects, the indication may be based at least in part on an MCS signaled by base station 110 to UE 120 (e.g., in a DCI). For example, a DCI indicating one or more DMRS ports assigned to UE 120 may also indicate an MCS to be used for communications (e.g., data communications, such as PDSCH communications) scheduled by the DCI (and for which channel estimation using DMRS is performed). The MCS (e.g., an MCS index value, a modulation scheme, a coding scheme, etc.) may specify whether one or more assigned DMRS ports (e.g., DMRS port 0 and DMRS port 2 in example 1200) are to be combined into a single virtual port. In some aspects, the DCI may indicate multiple DMRS ports assigned to UE 120, and UE 120 may use the MCS to determine whether to combine the multiple DMRS ports into a single virtual port. Alternatively, the DCI may indicate a single DMRS port assigned to the UE 120, and the UE 120 may use the MCS to determine whether to combine the indicated DMRS port with another (non-indicated) DMRS port from another CDM group into a single virtual port. In some aspects, the UE 120 may be configured with a set of DMRS ports to be combined depending on the MCS.

[0119] In some aspects, for single-layer MIMO, if UE 120 is assigned two DMRS ports, UE 120 may combine the two DMRS ports into a single virtual port based at least in part on determining that the two DMRS ports are assigned for single-layer MIMO. In this case, the indication to combine the ports may be implicit.

[0120] For example, if the MCS index signaled to UE 120 satisfies a threshold (e.g., is greater than a threshold, is greater than or equal to a threshold, etc.), UE 120 may determine that DMRS ports are to be combined because the performance of a higher MCS is more sensitive to channel estimation errors. As another example, if the MCS index signaled to UE 120 does not satisfy the threshold (e.g., is less than the threshold, is less than or equal to the threshold, etc.), UE 120 may determine that DMRS ports are not to be combined because the performance of a lower MCS is less sensitive to channel estimation errors.

[0121] Additionally or alternatively, the indication may be based at least in part on a subcarrier spacing and / or an estimated delay spread associated with the UE 120 and the base station 110. For example, the indication may be based at least in part on a subcarrier spacing configured and / or used for communications between the UE 120 and the base station. In some aspects, the subcarrier spacing and / or the estimated delay spread may specify whether to combine one or more assigned DMRS ports (e.g., DMRS port 0 and DMRS port 2 in example 1200) into a single virtual port, similar to the MCS example described above. In some aspects, the DCI may indicate multiple DMRS ports assigned to the UE 120, and the UE 120 may use the subcarrier spacing and / or the estimated delay spread to determine whether to combine the multiple DMRS ports into a single virtual port. Alternatively, the DCI may indicate a single DMRS port assigned to the UE 120, and the UE 120 may use the subcarrier spacing and / or the estimated delay spread to determine whether to combine the indicated DMRS port with another (non-indicated) DMRS port from another CDM group into a single virtual port. In some aspects, UE 120 may be configured with a set of DMRS ports to be combined depending on subcarrier spacing and / or estimated delay spread.

[0122] For example, if the subcarrier spacing and / or the estimated delay spread meets a threshold (e.g., is greater than a threshold, is greater than or equal to a threshold, etc.), UE 120 may determine that the DMRS ports are to be combined because communications with large subcarrier spacing and large delay spread are more sensitive to channel estimation errors. As another example, if the subcarrier spacing and / or the estimated delay spread does not meet the threshold (e.g., is less than the threshold, is less than or equal to the threshold, etc.), UE 120 may determine that the DMRS ports are not to be combined because communications with small subcarrier spacing and small delay spread are less sensitive to channel estimation errors.

[0123] In some aspects, UE 120 may determine whether the assigned DMRS ports are to be combined based at least in part on whether the MCS satisfies a first threshold, whether the subcarrier spacing satisfies a second threshold, and / or whether the estimated delay spread satisfies a third threshold. In some aspects, base station 110 may indicate one or more of these thresholds (e.g., the first threshold, the second threshold, and / or the third threshold, such as the MCS threshold, the subcarrier spacing threshold, and / or the delay spread threshold) to UE 120, such as in a configuration message, a MAC-CE, etc. In some aspects, one or more of these thresholds may be specified in a wireless communication standard.

[0124] As shown by reference numeral 1215, the base station 110 may transmit the DMRS according to the indication. For example, if the indication indicates that the DMRS ports are not to be combined, the base station 110 may use the DMRS port assigned to the UE 120 (e.g., as indicated in the DCI) to transmit a first DMRS transmission set to the UE 120. In some aspects, the base station 110 may also use a DMRS port that is not assigned to the UE 120 and is in the same CDM group as the DMRS port assigned to the UE 120 to transmit a second DMRS transmission set to another UE 120. Alternatively, if the indication indicates that the DMRS ports are to be combined, the base station 110 may use a single virtual port (e.g., which may be indicated in the DCI and / or assigned to the UE 120) to transmit the DMRS transmission set to the UE 120. In some aspects, the DMRS transmission set on the single virtual port is contained within a single codeword. In some aspects, the DMRS transmission set on the single virtual port spans multiple codewords, as described below in conjunction with Figure 16 and Figure 17 Described in more detail.

[0125] As indicated by reference numeral 1220, UE 120 may perform channel estimation based at least in part on the indication. For example, if the indication indicates that DMRS ports are not to be combined, UE 120 may receive a first DMRS transmission set using the DMRS ports assigned to UE 120 (e.g., as indicated in the DCI) and may perform channel estimation using the first DMRS transmission set. In some aspects, UE 120 may perform channel estimation using the first DMRS transmission set by de-CDMing the first DMRS transmission set (as described elsewhere herein) and / or by performing frequency domain interpolation on one or more resource elements (or subcarriers) on which the first DMRS transmission set was not received. Alternatively, if the indication indicates that DMRS ports are to be combined, UE 120 may receive the DMRS transmission set on a single virtual port and may perform channel estimation using the DMRS transmission set. In some aspects, the UE 120 can use the DMRS transmission set to perform channel estimation without de-CDMing the DMRS transmission set and / or without performing frequency domain interpolation (e.g., because the DMRS transmission set on a single virtual port covers all resource elements and subcarriers in a resource block). In this way, a full-density DMRS pattern can be achieved, which can improve the accuracy of channel estimation.

[0126] In some aspects, a third type of DMRS configuration (e.g., DMRS configuration type 3) may be defined by a wireless communication standard and / or may be configured by base station 110. The third type of DMRS configuration may use full-frequency density DMRS transmission. In this case, the DMRS transmission associated with a particular port may span all subcarriers within a resource block. The third type of DMRS configuration may be used when multiple DMRS ports are combined or not combined into a single DMRS port. For example, the third type of DMRS configuration may define a single DMRS port that spans all subcarriers within a resource block. Alternatively, the third type of DMRS configuration may define multiple DMRS ports that may be combined into a single virtual port that spans all subcarriers within a resource block. In this way, a full-density DMRS pattern may be achieved, which may improve the accuracy of channel estimation.

[0127] As indicated above, Figure 12 are provided as examples. Other examples may differ from those described in Figure 12 Examples described.

[0128] Figure 13 is a diagram illustrating an example 1300 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 12As described, base station 110 may indicate whether to combine two or more assigned DMRS ports into a single virtual port. In some aspects, this indication may be included in a DCI.

[0129] like Figure 13 As shown in , in some aspects, a single value (shown as "value") in the DCI indicates: the number of DMRS CDM groups without data and one or more DMRS ports assigned to the UE 120. As shown by reference numeral 1305, in some aspects, a single value may indicate: the number of DMRS CDM groups without data, a plurality of DMRS ports assigned to the UE 120, and whether the plurality of DMRS ports are to be combined into a single virtual port. In some aspects, one or more reserved bits of the DCI (e.g., having a legacy DCI format) may be used for this indication. By using a single value to indicate multiple parameters, signaling overhead may be saved. In some aspects, Figure 13 The table shown in (or indicating the combination of Figure 13 A similar table of values ​​described herein may be indicated by base station 110 to UE 120, such as in a configuration message.

[0130] As indicated above, Figure 13 are provided as examples. Other examples may differ from those described in Figure 13 Examples described.

[0131] Figure 14 is a diagram illustrating an example 1400 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 12 As described, base station 110 may indicate whether to combine two or more assigned DMRS ports into a single virtual port. In some aspects, this indication may be included in a DCI.

[0132] like Figure 14 As shown in , in some aspects, a single value (shown as "value") in the DCI indicates: the number of DMRS CDM groups with no data, one or more DMRS ports assigned to the UE 120, and the number of frontload symbols (e.g., for the DMRS). As shown by reference numeral 1405, in some aspects, a single value may indicate: the number of DMRS CDM groups with no data, a plurality of DMRS ports assigned to the UE 120, the number of frontload symbols, and whether the plurality of DMRS ports are to be combined into a single virtual port.

[0133] In some aspects, a DCI field (e.g., of a DCI having a legacy DCI format) may be extended to have a larger bit length to support this indication. By using a single value to indicate multiple parameters, signaling overhead may be saved. Alternatively, rather than extending the number of bits of this DCI field, a first field in the DCI may indicate the number of DMRS CDM groups that do not have data, a plurality of DMRS ports assigned to UE 120, and / or the number of frontload symbols, and a second field in the DCI may indicate whether the plurality of DMRS ports are to be combined into a single virtual port. In some aspects, the second field comprises a single bit. In some aspects, Figure 14 The table shown in (or indicating the combination of Figure 14 A similar table of values ​​described herein may be indicated by base station 110 to UE 120, such as in a configuration message.

[0134] As indicated above, Figure 14 are provided as examples. Other examples may differ from those described in Figure 14 Examples described.

[0135] Figure 15 is a diagram illustrating an example 1500 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 15 As shown in FIG, a DMRS table (e.g., a DMRS antenna port table) may include a set of values ​​(shown as entries in the "Value" column). Each value in the set of values ​​may indicate the number of DMRS CDM groups without data, one or more DMRS ports assigned to UE 120 (e.g., in some aspects, multiple DMRS ports assigned to UE 120), the number of frontload symbols, and / or whether multiple assigned DMRS ports are to be combined into a single virtual port. When a DMRS table (e.g., in combination with Figure 12-15 When any DMRS table shown or described herein is configured for UE 120, UE 120 may reference the DMRS table to determine one or more parameters corresponding to a value signaled to UE 120. For example, the value may be signaled in the DCI, and UE 120 may use the value to look up a corresponding entry in the DMRS table.

[0136] like Figure 15As shown in , in some aspects, a DMRS table 1505 configured for a first UE 120 (e.g., a first DMRS table) can be different from a DMRS table 1510 configured for the first UE 120 (e.g., a second DMRS table). In example 1500, a value of 0 in DMRS table 1505 for UE 0 indicates that DMRS port 0 and DMRS port 2 are assigned to UE 0, and DMRS port 0 and DMRS port 2 are to be combined into a single virtual port. However, a value of 0 in DMRS table 1510 for UE 1 indicates that DMRS port 1 and DMRS port 3 are assigned to UE 1, and DMRS port 1 and DMRS port 3 are to be combined into a single virtual port. In this way, the size of the DCI can be reduced or maintained (e.g., by avoiding adding DCI bits) while providing increased scheduling flexibility for base station 110.

[0137] As indicated above, Figure 15 are provided as examples. Other examples may differ from those described in Figure 15 Examples described.

[0138] Figure 16 is a diagram illustrating an example 1600 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 16 As shown in , a modified first type of DMRS configuration can support a maximum of two CDM groups, where different CDM groups are used for different symbols. In this configuration, a first CDM group (CDM group 0) can occupy a set of subcarriers or a subset of subcarriers on a first symbol, and a second CDM group (CDM group 1) can occupy a set of subcarriers or a subset of subcarriers on a second symbol. The first CDM group can include multiple DMRS ports, such as DMRS port 0 (shown as port 1000) and DMRS port 1, and the second CDM group can also include multiple DMRS ports, such as DMRS port 2 (shown as port 1002) and DMRS port 3.

[0139] In some aspects, this type of configuration may span two adjacent symbols, as shown by reference numeral 1605. In this configuration, a first CDM group (CDM group 0) may occupy a set or subset of subcarriers on a first symbol (shown as even subcarriers on symbol 2), and a second CDM group (CDM group 1) may occupy a set or subset of subcarriers on a second symbol (shown as odd subcarriers on symbol 3).

[0140] Alternatively, this type of configuration can span two non-adjacent symbols (e.g., a single-symbol DMRS configuration with an additional configured DMRS symbol), as shown by reference numeral 1610. In this configuration, a first CDM group (CDM group 0) can occupy a set or subset of subcarriers on the first symbol (shown as even subcarriers on symbol 2), and a second CDM group (CDM group 1) can occupy a set or subset of subcarriers on the second symbol (shown as odd subcarriers on symbol 7).

[0141] In some aspects, when using this configuration, multiple DMRS ports can be combined into a single virtual port, as described elsewhere herein. In this way, denser DMRS coverage in the frequency domain can be achieved. In addition, multiple DMRS symbols using the legacy DMRS configuration can be assigned different DMRS ports. Multiple DMRS symbols can be contiguous or non-contiguous.

[0142] As indicated above, Figure 16 are provided as examples. Other examples may differ from those described in Figure 16 Examples described.

[0143] Figure 17 is a diagram illustrating an example 1700 associated with DMRS design for large subcarrier spacing according to various aspects of the present disclosure. Figure 17 As shown in , the modified second type of DMRS configuration can support a maximum of three CDM groups, where different sets of those CDM groups are used for different codewords. In this configuration, as an example, a first CDM group (CDM group 0) and a second CDM group (CDM group 1) can occupy a set of subcarriers or a subset of subcarriers on the first codeword, and a third CDM group (CDM group 2) can occupy a set of subcarriers or a subset of subcarriers on the second codeword. The first CDM group can include multiple DMRS ports, such as DMRS port 0 (shown as port 1000) and DMRS port 1, the second CDM group can also include multiple DMRS ports, such as DMRS port 2 (shown as port 1002) and DMRS port 3, and the third CDM group can also include multiple DMRS ports, such as DMRS port 4 (shown as port 1004) and DMRS port 5.

[0144] In some aspects, this type of configuration can span two adjacent symbols, as shown by reference numeral 1705. In this case, a first CDM group can occupy a set or subset of subcarriers on the first symbol (shown as subcarriers 0, 1, 6, and 7 on symbol 2), a second CDM group can occupy a set or subset of subcarriers on the first symbol (shown as subcarriers 2, 3, 8, and 9 on symbol 2), and a third CDM group can occupy a set or subset of subcarriers on the second symbol (shown as subcarriers 4, 5, 10, and 11 on symbol 3). In this configuration, none of the CDM groups overlap in subcarriers, and the total set of CDM groups spans all subcarriers.

[0145] Alternatively, as shown by reference numeral 1710, this type of configuration can span two non-adjacent symbols (e.g., a single symbol DMRS configuration with an additional configured DMRS symbol). In this case, a first CDM group can occupy a set or subset of subcarriers on the first symbol (shown as subcarriers 0, 1, 6, and 7 on symbol 2), a second CDM group can occupy a set or subset of subcarriers on the first symbol (shown as subcarriers 2, 3, 8, and 9 on symbol 2), and a third CDM group can occupy a set or subset of subcarriers on the second symbol (shown as subcarriers 4, 5, 10, and 11 on symbol 7). As described above, none of the CDM groups overlap in subcarriers, and the total set of CDM groups spans all subcarriers.

[0146] In some aspects, when using this configuration, multiple DMRS ports can be combined into a single virtual port, as described elsewhere herein. In this way, denser DMRS coverage in the frequency domain can be achieved. In addition, multiple DMRS symbols using the legacy DMRS configuration can be assigned different DMRS ports. Multiple DMRS symbols can be contiguous or non-contiguous.

[0147] As indicated above, Figure 17 are provided as examples. Other examples may differ from those described in Figure 17 Examples described.

[0148] Figure 18 is a diagram illustrating an example process 1800, performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 1800 is an example of operations in which a UE (eg, UE 120, etc.) performs operations associated with demodulation reference signal design for large subcarrier spacing.

[0149] like Figure 18As shown in , in some aspects, process 1800 may include receiving a DMRS configuration that indicates a CDM group configured for the UE (block 1810). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive a DMRS configuration that indicates a CDM group configured for the UE, as described above.

[0150] like Figure 18 As further shown in FIG. 1 , in some aspects, process 1800 may include receiving a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving the first set of DMRS transmissions (block 1820). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive the first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving the first set of DMRS transmissions, as described above.

[0151] like Figure 18 As further shown in FIG. 1 , in some aspects, process 1800 may include receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE (block 1830). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE, as described above.

[0152] like Figure 18 As further shown in FIG. 1 , in some aspects, process 1800 may include performing channel estimation based at least in part on the first indication of the antenna port and the second indication of whether a second DMRS transmission set for the other antenna port exists (block 1840). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may perform channel estimation based at least in part on the first indication of the antenna port and the second indication of whether a second DMRS transmission set for the other antenna port exists, as described above.

[0153] Process 1800 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in conjunction with one or more other processes described elsewhere herein.

[0154] In a first aspect, performing the channel estimation includes one of: performing the channel estimation using an orthogonal cover code if a second DMRS transmission set for the other antenna port exists, or performing the channel estimation without using an orthogonal cover code if a second DMRS transmission set for the other antenna port does not exist.

[0155] In a second aspect, alone or in combination with the first aspect, the second indication is included in the downlink control information.

[0156] In a third aspect, alone or in combination with one or more of the first and second aspects, the first indication and the second indication are indicated using the same field of the downlink control information.

[0157] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the first indication and the second indication are indicated using a single value in the downlink control information.

[0158] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, a single value in the downlink control information indicates: the number of CDM groups without data, the antenna port assigned to the UE, and whether a second DMRS transmission set for the other antenna port exists for the other UE.

[0159] In a sixth aspect, alone or in combination with one or more of the first to fifth aspects, a first field in the downlink control information includes a first indication, and a second field in the downlink control information includes a second indication.

[0160] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, the second field comprises a single bit.

[0161] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a DMRS table including at least one of the first indication or the second indication included in the DMRS configuration is different for the UE compared to the other UE.

[0162] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the second indication is included in a configuration message including the DMRS configuration.

[0163] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the configuration message is a radio resource control message.

[0164] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the second indication is at least partially based on a modulation and coding scheme (MCS) signaled to the UE in association with the first indication of the antenna port assigned to the UE.

[0165] In the twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the UE is configured to determine that the second DMRS transmission set does not exist if the MCS index signaled to the UE meets a threshold, and the UE is configured to determine that the second DMRS transmission set exists if the MCS index does not meet the threshold.

[0166] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the threshold is signaled to the UE.

[0167] In a fourteenth aspect, alone or in combination with one or more of aspects one to thirteen, the second indication is included in at least one of a configuration message, downlink control information (DCI), an activation DCI, a media access control (MAC) control element, or a combination thereof.

[0168] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the second indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0169] although Figure 18 Example blocks of process 1800 are shown, but in some aspects, process 1800 may include Figure 18 1800. In some embodiments, the process 1800 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. Additionally or alternatively, two or more blocks of process 1800 may be executed in parallel.

[0170] Figure 19 is a diagram illustrating an example process 1900, performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process 1900 is an example of operations in which a base station (eg, base station 110, etc.) performs operations associated with demodulation reference signal design for large subcarrier spacing.

[0171] like Figure 19 As shown in , in some aspects, process 1900 may include transmitting a DMRS configuration that indicates a CDM group configured for the UE (block 1910). For example, a base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit a DMRS configuration that indicates a CDM group configured for the UE, as described above.

[0172] like Figure 19As further shown in FIG. 1 , in some aspects, process 1900 may include transmitting a first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving the first set of DMRS transmissions (block 1920). For example, a base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit the first indication of an antenna port included in the CDM group, the antenna port assigned to the UE for receiving the first set of DMRS transmissions, as described above.

[0173] like Figure 19 As further shown in FIG. 1 , in some aspects, process 1900 may include transmitting a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE (block 1930). For example, the base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE, as described above.

[0174] like Figure 19 As further shown in FIG. 1 , in some aspects, process 1900 may include transmitting a first DMRS transmission set based at least in part on the first indication and the second indication (block 1940). For example, the base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit the first DMRS transmission set based at least in part on the first indication and the second indication, as described above.

[0175] Process 1900 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in conjunction with one or more other processes described elsewhere herein.

[0176] In the first aspect, the second indication is included in downlink control information.

[0177] In a second aspect, alone or in combination with the first aspect, the first indication and the second indication are indicated using the same field of the downlink control information.

[0178] In a third aspect, alone or in combination with one or more of the first and second aspects, the first indication and the second indication are indicated using a single value in the downlink control information.

[0179] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, a single value in the downlink control information indicates: the number of CDM groups without data, the antenna port assigned to the UE, and whether a second DMRS transmission set for the other antenna port exists for the other UE.

[0180] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, a first field in the downlink control information includes a first indication, and a second field in the downlink control information includes a second indication.

[0181] In a sixth aspect, alone or in combination with one or more of the first to fifth aspects, the second field comprises a single bit.

[0182] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, a DMRS table including at least one of the first indication or the second indication included in the DMRS configuration is different for the UE compared to the other UE.

[0183] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, the second indication is included in a configuration message including the DMRS configuration.

[0184] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the configuration message is a radio resource control message.

[0185] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the second indication is based at least in part on an MCS signaled to the UE in association with the first indication of the antenna port assigned to the UE.

[0186] In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the UE is configured to determine that the second DMRS transmission set does not exist when the MCS index signaled to the UE meets a threshold, and the UE is configured to determine that the second DMRS transmission set exists when the MCS index does not meet the threshold.

[0187] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the threshold is signaled to the UE.

[0188] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the second indication is included in at least one of a configuration message, a DCI, an activation DCI, a MAC control element, or a combination thereof.

[0189] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the second indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0190] although Figure 19 Example blocks of process 1900 are shown, but in some aspects, process 1900 may include Figure 19 1900. Additionally or alternatively, two or more blocks of process 1900 may be executed in parallel.

[0191] Figure 20 is a diagram illustrating an example process 2000, performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 2000 is an example in which a UE (eg, UE 120, etc.) performs operations associated with demodulation reference signal design for large subcarrier spacing.

[0192] like Figure 20 As shown in , in some aspects, process 2000 may include receiving a DMRS configuration that indicates a first CDM group and a second CDM group configured for the UE (block 2010). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive the DMRS configuration that indicates a first CDM group and a second CDM group configured for the UE, as described above.

[0193] like Figure 20 As further shown in FIG. 2 , in some aspects, process 2000 may include receiving an indication that a first antenna port included in a first CDM group and a second antenna port included in a second CDM group are to be combined into a single virtual port for use in a DMRS transmission set (block 2020). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive an indication that a first antenna port included in a first CDM group and a second antenna port included in a second CDM group are to be combined into a single virtual port for use in a DMRS transmission set, as described above.

[0194] like Figure 20 As further shown in FIG20 , in some aspects, process 2000 may include performing channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined (block 2030). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may perform channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined, as described above.

[0195] Process 2000 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in conjunction with one or more other processes described elsewhere herein.

[0196] In a first aspect, performing the channel estimation includes performing the channel estimation on all subcarriers or resource elements in a scheduled resource block without using frequency domain interpolation.

[0197] In a second aspect, alone or in combination with the first aspect, the indication is included in the DMRS configuration, and the DMRS configuration indicates a DMRS configuration type using full-frequency-density DMRS transmission.

[0198] In a third aspect, alone or in combination with one or more of the first and second aspects, the indication is included in downlink control information.

[0199] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using the same field of the downlink control information.

[0200] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using a single value in the downlink control information.

[0201] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, a single value in the downlink control information indicates: the number of CDM groups with no data, the first antenna port, the second antenna port, and the first antenna port and the second antenna port to be combined.

[0202] In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, a first field in the downlink control information indicates a first antenna port and a second antenna port, and a second field in the downlink control information includes an indication that the first antenna port and the second antenna port are to be combined.

[0203] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, the second field comprises a single bit.

[0204] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, a DMRS table including the indication included in the DMRS configuration is different for the UE compared to another UE.

[0205] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the indication is included in a configuration message including the DMRS configuration.

[0206] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the configuration message is a radio resource control message.

[0207] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the indication is based at least in part on an MCS signaled to the UE.

[0208] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the UE is configured to combine the first antenna port and the second antenna port if an MCS index signaled to the UE satisfies a threshold.

[0209] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the threshold is signaled to the UE.

[0210] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the indication is included in at least one of a configuration message, a DCI, an activation DCI, a MAC control element, or a combination thereof.

[0211] In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the set of DMRS transmissions on the single virtual port is contained within a single symbol.

[0212] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, the DMRS transmission set on the single virtual port spans multiple symbols.

[0213] In an eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, the indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0214] although Figure 20 Example blocks of process 2000 are shown, but in some aspects, process 2000 may include Figure 20 2000. Additionally or alternatively, two or more blocks of process 2000 may be executed in parallel.

[0215] Figure 21is a diagram illustrating an example process 2100, performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process 2100 is an example of operations in which a base station (eg, base station 110, etc.) performs operations associated with demodulation reference signal design for large subcarrier spacing.

[0216] like Figure 21 As shown in , in some aspects, process 2100 may include transmitting a DMRS configuration that indicates a first CDM group and a second CDM group configured for the UE (block 2110). For example, a base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit a DMRS configuration that indicates a first CDM group and a second CDM group configured for the UE, as described above.

[0217] like Figure 21 As further shown in FIG. 2 , in some aspects, process 2100 may include transmitting an indication that a first antenna port included in a first CDM group and a second antenna port included in a second CDM group are to be combined into a single virtual port for use in a DMRS transmission set (block 2120). For example, a base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit an indication that a first antenna port included in a first CDM group and a second antenna port included in a second CDM group are to be combined into a single virtual port for use in a DMRS transmission set, as described above.

[0218] like Figure 21 As further shown in FIG2 , in some aspects, process 2100 may include transmitting the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined (block 2130). For example, the base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined, as described above.

[0219] Process 2100 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in conjunction with one or more other processes described elsewhere herein.

[0220] In a first aspect, the indication is included in the DMRS configuration, and the DMRS configuration indicates a DMRS configuration type using full frequency density DMRS transmission.

[0221] In a second aspect, alone or in combination with the first aspect, the indication is included in downlink control information.

[0222] In a third aspect, alone or in combination with one or more of the first and second aspects, the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using the same field of the downlink control information.

[0223] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using a single value in the downlink control information.

[0224] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, a single value in the downlink control information indicates: the number of CDM groups without data, the first antenna port, the second antenna port, and the first antenna port and the second antenna port to be combined.

[0225] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, a first field in the downlink control information indicates a first antenna port and a second antenna port, and a second field in the downlink control information includes an indication that the first antenna port and the second antenna port are to be combined.

[0226] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, the second field comprises a single bit.

[0227] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, a DMRS table including the indication included in the DMRS configuration is different for the UE compared to another UE.

[0228] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the indication is included in a configuration message including the DMRS configuration.

[0229] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the configuration message is a radio resource control message.

[0230] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the indication is based at least in part on an MCS signaled to the UE.

[0231] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the UE is configured to combine the first antenna port and the second antenna port if an MCS index signaled to the UE satisfies a threshold.

[0232] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the threshold is signaled to the UE.

[0233] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the indication is included in at least one of a configuration message, a DCI, an activation DCI, a MAC control element, or a combination thereof.

[0234] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the set of DMRS transmissions on the single virtual port is contained within a single symbol.

[0235] In a sixteenth aspect, alone or in combination with one or more of the first to fifteenth aspects, the DMRS transmission set on the single virtual port spans multiple symbols.

[0236] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, the indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0237] although Figure 21 Example blocks of process 2100 are shown, but in some aspects, process 2100 may include Figure 21 21. In some embodiments, the process 2100 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. Additionally or alternatively, two or more blocks of process 2100 may be executed in parallel.

[0238] The following provides an overview of some aspects of the disclosure:

[0239] Aspect 1: A wireless communication method performed by a user equipment (UE), comprising: receiving a demodulation reference signal (DMRS) configuration, the DMRS configuration indicating a code division multiplexing (CDM) group configured for the UE; receiving a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and performing channel estimation based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set for the other antenna port exists.

[0240] Aspect 2: A method as in Aspect 1, wherein performing the channel estimation includes one of: if a second DMRS transmission set for the other antenna port exists, performing the channel estimation using an orthogonal cover code, or if the second DMRS transmission set for the other antenna port does not exist, performing the channel estimation without using an orthogonal cover code.

[0241] Aspect 3: The method according to any one of aspects 1-2, wherein the second indication is included in downlink control information.

[0242] Aspect 4: The method according to any one of aspects 1 to 3, wherein the first indication and the second indication are indicated using the same field of the downlink control information.

[0243] Aspect 5: The method according to any one of aspects 1 to 4, wherein the first indication and the second indication are indicated using a single value in the downlink control information.

[0244] Aspect 6: A method as in any one of Aspects 1-5, wherein a single value in the downlink control information indicates: the number of CDM groups without data, the antenna port assigned to the UE, and whether a second DMRS transmission set for the other antenna port exists for the other UE.

[0245] Aspect 7: The method according to any one of aspects 1-2, wherein the first field in the downlink control information includes a first indication, and wherein the second field in the downlink control information includes a second indication.

[0246] Aspect 8: The method of aspect 7, wherein the second field comprises a single bit.

[0247] Aspect 9: The method according to any one of aspects 1 to 8, wherein a DMRS table including at least one of the first indication or the second indication included in the DMRS configuration is different for the UE compared to the other UE.

[0248] Aspect 10: The method according to any one of aspects 1-9, wherein the second indication is included in a configuration message including the DMRS configuration.

[0249] Aspect 11: The method of aspect 10, wherein the configuration message is a radio resource control message.

[0250] Aspect 12: The method of any of aspects 1-11, wherein the second indication is based at least in part on a modulation and coding scheme (MCS) signaled to the UE in association with the first indication of the antenna port assigned to the UE.

[0251] Aspect 13: A method as in Aspect 12, wherein the UE is configured to determine that the second DMRS transmission set does not exist if the MCS index signaled to the UE meets a threshold, and wherein the UE is configured to determine that the second DMRS transmission set exists if the MCS index does not meet the threshold.

[0252] Aspect 14: The method of aspect 13, wherein the threshold is signaled to the UE.

[0253] Aspect 15: The method of any one of aspects 1-14, wherein the second indication is included in at least one of a configuration message, downlink control information (DCI), activation DCI, a medium access control (MAC) control element, or a combination thereof.

[0254] Aspect 16: The method of any of aspects 1-15, wherein the second indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0255] Aspect 17: A wireless communication method performed by a base station, comprising: transmitting a demodulation reference signal (DMRS) configuration, the DMRS configuration indicating a code division multiplexing (CDM) group configured for a user equipment (UE); transmitting a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; transmitting a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE; and transmitting the first DMRS transmission set based at least in part on the first indication and the second indication.

[0256] Aspect 18: The method of aspect 17, wherein the second indication is included in downlink control information.

[0257] Aspect 19: The method according to any one of aspects 17-18, wherein the first indication and the second indication are indicated using the same field of the downlink control information.

[0258] Aspect 20: The method according to any one of aspects 17 to 19, wherein the first indication and the second indication are indicated using a single value in the downlink control information.

[0259] Aspect 21: A method as in any one of Aspects 17-20, wherein a single value in the downlink control information indicates: the number of CDM groups without data, the antenna port assigned to the UE, and whether a second DMRS transmission set for the other antenna port exists for the other UE.

[0260] Aspect 22: The method according to any one of aspects 17-18, wherein the first field in the downlink control information comprises a first indication, and wherein the second field in the downlink control information comprises a second indication.

[0261] Aspect 23: The method of aspect 22, wherein the second field comprises a single bit.

[0262] Aspect 24: The method according to any one of aspects 17-23, wherein a DMRS table including at least one of the first indication or the second indication included in the DMRS configuration is different for the UE compared to the other UE.

[0263] Aspect 25: The method according to any one of aspects 17-24, wherein the second indication is included in a configuration message including the DMRS configuration.

[0264] Aspect 26: The method of Aspect 25, wherein the configuration message is a radio resource control message.

[0265] Aspect 27: The method of any of aspects 17-26, wherein the second indication is based at least in part on a modulation and coding scheme (MCS) signaled to the UE in association with the first indication of the antenna port assigned to the UE.

[0266] Aspect 28: A method as in Aspect 27, wherein the UE is configured to determine that the second DMRS transmission set does not exist if the MCS index signaled to the UE meets a threshold, and wherein the UE is configured to determine that the second DMRS transmission set exists if the MCS index does not meet the threshold.

[0267] Aspect 29: The method of aspect 28, wherein the threshold is signaled to the UE.

[0268] Aspect 30: The method of any one of aspects 17-29, wherein the second indication is included in at least one of a configuration message, downlink control information (DCI), activation DCI, a medium access control (MAC) control element, or a combination thereof.

[0269] Aspect 31: The method of any of aspects 17-30, wherein the second indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0270] Aspect 32: A wireless communication method performed by a user equipment (UE), comprising: receiving a demodulation reference signal (DMRS) configuration, the DMRS configuration indicating a first code division multiplexing (CDM) group and a second CDM group configured for the UE; receiving an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and performing channel estimation using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0271] Aspect 33: The method of aspect 32, wherein in the first aspect, performing the channel estimation comprises: performing the channel estimation on all subcarriers or resource elements in the scheduled resource block without using frequency domain interpolation.

[0272] Aspect 34: The method according to any one of aspects 32-33, wherein the indication is included in the DMRS configuration, wherein the DMRS configuration indicates a DMRS configuration type using full frequency density DMRS transmission.

[0273] Aspect 35: The method according to any one of aspects 32-34, wherein the indication is included in downlink control information.

[0274] Aspect 36: The method according to any one of aspects 32-35, wherein the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using the same field of the downlink control information.

[0275] Aspect 37: The method of any one of aspects 32-36, wherein the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using a single value in the downlink control information.

[0276] Aspect 38: The method of any of aspects 32-37, wherein a single value in the downlink control information indicates: the number of CDM groups without data, the first antenna port, the second antenna port, and whether the first antenna port and the second antenna port are to be combined.

[0277] Aspect 39: A method as described in any of Aspects 32-35, wherein the first field in the downlink control information indicates the first antenna port and the second antenna port, and wherein the second field in the downlink control information includes the indication that the first antenna port and the second antenna port are to be combined.

[0278] Aspect 40: The method of aspect 39, wherein the second field comprises a single bit.

[0279] Aspect 41: The method according to any one of aspects 32-40, wherein a DMRS table including the indication included in the DMRS configuration is different for the UE compared to another UE.

[0280] Aspect 42: The method according to any one of Aspects 32-41, wherein the indication is included in a configuration message including the DMRS configuration.

[0281] Aspect 43: The method of Aspect 42, wherein the configuration message is a radio resource control message.

[0282] Aspect 44: The method of any of aspects 32-43, wherein the indication is based at least in part on a modulation and coding scheme (MCS) signaled to the UE.

[0283] Aspect 45: The method of aspect 44, wherein the UE is configured to combine the first antenna port and the second antenna port if an MCS index signaled to the UE satisfies a threshold.

[0284] Aspect 46: The method of aspect 45, wherein the threshold is signaled to the UE.

[0285] Aspect 47: The method of any of aspects 32-46, wherein the indication is included in at least one of a configuration message, downlink control information (DCI), activation DCI, a medium access control (MAC) control element, or a combination thereof.

[0286] Aspect 48: The method of any one of Aspects 32-47, wherein the set of DMRS transmissions on the single virtual port is contained within a single symbol.

[0287] Aspect 49: The method of any one of Aspects 32-47, wherein the DMRS transmission set on the single virtual port spans multiple symbols.

[0288] Aspect 50: The method of any of aspects 32-49, wherein the indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0289] Aspect 51: A wireless communication method performed by a base station, comprising: transmitting a demodulation reference signal (DMRS) configuration, the DMRS configuration indicating a first code division multiplexing (CDM) group and a second CDM group configured for the user equipment (UE); receiving an indication that a first antenna port included in the first CDM group and a second antenna port included in the second CDM group are to be combined into a single virtual port for a DMRS transmission set; and transmitting the DMRS set using the single virtual port based at least in part on the indication that the first antenna port and the second antenna port are to be combined.

[0290] Aspect 52: The method of aspect 51, wherein the indication is included in the DMRS configuration, wherein the DMRS configuration indicates a configuration type of using full frequency density DMRS transmission.

[0291] Aspect 53: The method according to any one of aspects 51-52, wherein the indication is included in downlink control information.

[0292] Aspect 54: The method according to any one of aspects 51-53, wherein the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using the same field of the downlink control information.

[0293] Aspect 55: The method of any one of aspects 51-54, wherein the first antenna port, the second antenna port, and the indication that the first antenna port and the second antenna port are to be combined are indicated using a single value in the downlink control information.

[0294] Aspect 56: The method of any one of aspects 51-55, wherein a single value in the downlink control information indicates: the number of CDM groups without data, the first antenna port, the second antenna port, and whether the first antenna port and the second antenna port are to be combined.

[0295] Aspect 57: A method as in any of Aspects 51-53, wherein the first field in the downlink control information indicates the first antenna port and the second antenna port, and wherein the second field in the downlink control information includes the indication that the first antenna port and the second antenna port are to be combined.

[0296] Aspect 58: The method of aspect 57, wherein the second field comprises a single bit.

[0297] Aspect 59: The method according to any one of aspects 51-58, wherein a DMRS table including the indication included in the DMRS configuration is different for the UE compared to another UE.

[0298] Aspect 60: The method according to any one of aspects 51-59, wherein the indication is included in a configuration message including the DMRS configuration.

[0299] Aspect 61: The method of Aspect 60, wherein the configuration message is a radio resource control message.

[0300] Aspect 62: The method of any of Aspects 51-61, wherein the indication is based at least in part on a modulation and coding scheme (MCS) signaled to the UE.

[0301] Aspect 63: The method of aspect 62, wherein the UE is configured to combine the first antenna port and the second antenna port if an MCS index signaled to the UE satisfies a threshold.

[0302] Aspect 64: The method of aspect 63, wherein the threshold is signaled to the UE.

[0303] Aspect 65: The method of any one of aspects 51-64, wherein the indication is included in at least one of a configuration message, downlink control information (DCI), activation DCI, a medium access control (MAC) control element, or a combination thereof.

[0304] Aspect 66: The method of any one of Aspects 51-65, wherein the set of DMRS transmissions on the single virtual port is contained within a single symbol.

[0305] Aspect 67: The method of any one of Aspects 51-65, wherein the DMRS transmission set on the single virtual port spans multiple symbols.

[0306] Aspect 68: The method of any of Aspects 51-67, wherein the indication is based at least in part on at least one of subcarrier spacing, delay spread, or a combination thereof.

[0307] Aspect 69: An apparatus for wireless communication at a device, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method as in one or more of Aspects 1 to 16 and / or 32 to 50.

[0308] Aspect 70: A device for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors being configured to perform the method of one or more aspects 1 to 16 and / or 32 to 50.

[0309] Aspect 71: An apparatus for wireless communication, comprising at least one means for performing the method of one or more of aspects 1 to 16 and / or 32 to 50.

[0310] Aspect 72: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more of aspects 1 to 16 and / or 32 to 50.

[0311] Aspect 73: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions that, when executed by one or more processors of a device, causes the device to perform a method as in one or more of aspects 1 to 16 and / or 32 to 50.

[0312] Aspect 74: An apparatus for wireless communication at a device, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method as in one or more of Aspects 17 to 31 and / or 51 to 68.

[0313] Aspect 75: A device for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors being configured to perform the method of one or more aspects of aspects 17 to 31 and / or 51 to 68.

[0314] Aspect 76: An apparatus for wireless communication, comprising at least one means for performing the method of one or more of Aspects 17 to 31 and / or 51 to 68.

[0315] Aspect 77: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more aspects of aspects 17 to 31 and / or 51 to 68.

[0316] Aspect 78: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions that, when executed by one or more processors of a device, causes the device to perform a method as in one or more aspects 17 to 31 and / or 51 to 68.

[0317] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

[0318] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. As used herein, a processor is implemented using hardware, firmware, and / or a combination of hardware and software.

[0319] As used herein, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0320] It will be apparent that the systems and / or methods described herein can be implemented in various forms of hardware, firmware, and / or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit the aspects. Thus, the operation and behavior of these systems and / or methods are described herein without reference to specific software code—it is understood that software and hardware can be designed to implement these systems and / or methods based, at least in part, on the description herein.

[0321] Although specific feature combinations are described in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various aspects. In fact, many of these features can be combined in a manner not specifically described in the claims and / or not disclosed in the specification. Although each dependent claim listed below can be directly subordinate to only one claim, the disclosure of the various aspects includes that each dependent claim is combined with each other claim in this group of claims. The phrase quoting "at least one of" a list of items refers to any combination of these items, including single members. As an example, "at least one of a, b or c" is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other arrangement of a, b and c).

[0322] The elements, actions or instructions used herein should not be interpreted as critical or necessary unless explicitly described as such. Moreover, as used herein, the articles "one" and "a" are intended to include one or more items and can be used interchangeably with "one or more". Furthermore, as used herein, the terms "set" and "group" are intended to include one or more items (e.g., related items, non-related items, a combination of related and non-related items, etc.) and can be used interchangeably with "one or more". Where intended to have only one item, the phrase "only one" or similar language is used. Furthermore, as used herein, the terms "having", "containing", "comprising" etc. are intended to be open terms. Furthermore, the phrase "based on" is intended to mean "based at least in part on", unless otherwise explicitly stated.

Claims

1. A method for performing wireless communication by a user equipment (UE), comprising: receiving a demodulation reference signal (DMRS) configuration indicating a code division multiplexing (CDM) group configured for the UE; receiving a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE, wherein the second indication is based at least in part on a modulation and coding scheme (MCS) signaled to the UE in association with the first indication of the antenna port assigned to the UE, and / or wherein the second indication is based at least in part on at least one of a subcarrier spacing, a delay spread, or a combination thereof; receiving the first DMRS transmission set; and Channel estimation is performed using the first DMRS transmission set and based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set for the other antenna port is present.

2. The method according to claim 1, wherein Performing the channel estimation includes one of: If the second DMRS transmission set for the other antenna port exists, performing the channel estimation using an orthogonal cover code, or If the second DMRS transmission set for the another antenna port does not exist, the channel estimation is performed without using an orthogonal cover code.

3. The method according to claim 1, wherein The second indication is included in downlink control information, and wherein the first indication and the second indication are indicated using at least one of a same field or a single value in the downlink control information.

4. The method according to claim 1, wherein A single value in the downlink control information indicates the number of CDM groups having no data, the antenna port assigned to the UE, and whether the second DMRS transmission set for the another antenna port exists for the another UE.

5. The method according to claim 1, wherein A first field in downlink control information includes the first indication, and wherein a second field in the downlink control information includes the second indication.

6. The method of claim 1, wherein: A DMRS table included in the DMRS configuration and including at least one of the first indication or the second indication is different for the UE compared to the other UE.

7. The method of claim 1, wherein: The UE is configured to determine that the second DMRS transmission set does not exist if an MCS index signaled to the UE meets a threshold, and wherein the UE is configured to determine that the second DMRS transmission set exists if the MCS index does not meet the threshold.

8. A user equipment (UE) for wireless communication, comprising: Memory; as well as one or more processors operatively coupled to the memory, the memory and the one or more processors being configured to: receiving a demodulation reference signal (DMRS) configuration indicating a code division multiplexing (CDM) group configured for the UE; receiving a first indication of an antenna port included in the CDM group, the antenna port being assigned to the UE for receiving a first DMRS transmission set; receiving a second indication of whether a second DMRS transmission set for another antenna port included in the CDM group exists for another UE, wherein the second indication is based at least in part on a modulation and coding scheme (MCS) signaled to the UE in association with the first indication of the antenna port assigned to the UE, and / or wherein the second indication is based at least in part on at least one of a subcarrier spacing, a delay spread, or a combination thereof; receiving the first DMRS transmission set; and Channel estimation is performed using the first DMRS transmission set and based at least in part on the first indication of the antenna port and the second indication of whether the second DMRS transmission set for the other antenna port is present.

9. The UE according to claim 8, wherein: The one or more processors, when performing the channel estimation, are configured to: If the second DMRS transmission set for the other antenna port exists, performing the channel estimation using an orthogonal cover code, or If the second DMRS transmission set for the another antenna port does not exist, the channel estimation is performed without using an orthogonal cover code.

10. The UE according to claim 8, wherein: The second indication is included in downlink control information, and wherein the first indication and the second indication are indicated using at least one of a same field or a single value in the downlink control information.

11. The UE according to claim 8, wherein: A single value in the downlink control information indicates the number of CDM groups having no data, the antenna port assigned to the UE, and whether the second DMRS transmission set for the another antenna port exists for the another UE.

12. The UE according to claim 8, wherein: A first field in downlink control information includes the first indication, and wherein a second field in the downlink control information includes the second indication.

13. The UE according to claim 8, wherein: A DMRS table included in the DMRS configuration and including at least one of the first indication or the second indication is different for the UE compared to the other UE.

14. The UE according to claim 8, wherein: The UE is configured to determine that the second DMRS transmission set does not exist if an MCS index signaled to the UE meets a threshold, and wherein the UE is configured to determine that the second DMRS transmission set exists if the MCS index does not meet the threshold.

Images