Demodulation reference signal (DM-RS) design for rate split multi-user multiple-input multiple-output (MU-MIMO) communication

Abstract

A method of wireless communication is disclosed. The method is performed at a user equipment (UE). The method includes receiving downlink control information (DCI) for a downlink transmission from a network entity, where the downlink transmission is based on a rate division multiple access scheme, and where the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and a DM-RS for the private stream; determining a DM-RS configuration of the DM-RS for the common stream and the DM-RS for the private stream on the basis of the DCI; and receiving the downlink transmission based on the DM-RS configuration.

Description

[0001] Cross-references

[0002] This patent application claims priority to U.S. patent application No. 17 / 940,355, filed by Khoshnevisan et al. on September 8, 2022, entitled "DEMODULATION REFERENCE SIGNAL (DM-RS) DESIGN FOR RATE-SPLITTING MULTI-USERMULTIPLE INPUT MULTIPLE OUTPUT (MU-MIMO) COMMUNICATION," which is assigned to the assignee of this application and is expressly incorporated herein by reference. Background Art

[0003] Aspects of the present disclosure relate generally to wireless communications, and more particularly to techniques and apparatuses for multi-user multiple-input multiple-output (MU-MIMO) communications.

[0004] 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 that can support 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, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0005] A wireless communication network may include several base stations (BS) that can support communication of several user equipments (UEs). User equipments (UEs) may communicate with base stations (BSs) via downlinks and uplinks. Downlinks (or forward links) refer to the communication link from BS to UE, while uplinks (or reverse links) refer to the communication link from UE to BS. As will be described in more detail herein, BSs may also be referred to as Node Bs, gNBs, Access Points (APs), Radio Heads, Transmit Receive Points (TRPs), New Radio (NR) BSs, 5G Node Bs, and the like.

[0006] 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 level. LTE / Advanced LTE is an enhancement set of the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). New Radio (NR) (also known as 5G) is an enhancement set to the LTE mobile standard issued by the Third Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by: improving spectrum efficiency; reducing costs; improving services; utilizing new spectrum; and using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with 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) to better integrate with other open standards; and supporting beamforming, multiple input multiple output (MIMO) antenna technology and carrier aggregation.

[0007] However, as the demand for mobile broadband access continues to increase, wireless communications need further improvements. Preferably, these improvements should apply to LTE and / or NR, and / or also to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

[0008] In some aspects of the present disclosure, a method for wireless communication is disclosed, which is performed at a user equipment (UE), and the method may include: receiving downlink control information (DCI) for downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream; determining a DM-RS configuration for the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and receiving the downlink transmission based on the DM-RS configuration.

[0009] In some aspects of the present disclosure, another method for wireless communication is disclosed, which is performed at a network entity and may include: determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; sending the DCI to a user equipment (UE); generating the downlink transmission based on the DM-RS configuration; and sending the downlink transmission to the UE.

[0010] In some aspects of the present disclosure, an apparatus for wireless communication is disclosed, which may include a memory and one or more processors coupled to the memory, the memory and the one or more processors being configured to: receive downlink control information (DCI) for downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream; determine a DM-RS configuration for the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and receive the downlink transmission based on the DM-RS configuration.

[0011] In some aspects of the present disclosure, another apparatus for wireless communication is disclosed, which may include a memory and one or more processors coupled to the memory, the memory and the one or more processors being configured to: determine a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; generate downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; send the DCI to a user equipment (UE); generate the downlink transmission based on the DM-RS configuration; and send the downlink transmission to the UE.

[0012] In some aspects of the present disclosure, an apparatus for wireless communication is disclosed (e.g., the apparatus is configured to be used at a first wireless node), which may include: a component for receiving downlink control information (DCI) for downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream; a component for determining a DM-RS configuration for the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and a component for receiving the downlink transmission based on the DM-RS configuration.

[0013] In some aspects of the present disclosure, another apparatus for wireless communication is disclosed (e.g., the apparatus is configured for use at a second wireless node), which may include: a component for determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; a component for generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; a component for sending the DCI to a user equipment (UE); a component for generating the downlink transmission based on the DM-RS configuration; and a component for sending the downlink transmission to the UE.

[0014] In some aspects of the present disclosure, a non-transitory computer-readable medium storing one or more instructions for wireless communication is disclosed. The one or more instructions, when executed by one or more processors, may cause the one or more processors to: receive downlink control information (DCI) for downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and a DM-RS for the private stream; determine a DM-RS configuration for the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and receive the downlink transmission based on the DM-RS configuration.

[0015] In some aspects of the present disclosure, a non-transitory computer-readable medium storing one or more instructions for wireless communication is disclosed. The one or more instructions, when executed by one or more processors, may cause the one or more processors to: determine a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; generate downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; send the DCI to a user equipment (UE); generate the downlink transmission based on the DM-RS configuration; and send the downlink transmission to the UE.

[0016] The features and technical advantages of examples according to the present disclosure have been outlined quite extensively above so that the following specific embodiments may be better understood. Additional features and advantages will be described below. The disclosed concepts and specific examples may be easily used as a basis for modifying or designing other structures for the same purpose of achieving the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. When considered in conjunction with the accompanying drawings, the characteristics of the concepts disclosed herein (both their organization and methods of operation) and the associated advantages will be better understood according to the following description. Each of the figures in the accompanying drawings is provided for the purpose of illustration and description, and not as a definition of limitations to the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to be able to understand the above-mentioned features of the present disclosure in detail, a more specific description briefly summarized above may be obtained by reference to various aspects (some of which are illustrated in the accompanying drawings). However, it should be noted that the accompanying drawings only illustrate certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the specification may admit of other equally effective aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0018] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with various aspects of the present disclosure.

[0019] Figure 2 is a block diagram conceptually illustrating an example of a base station communicating with a user equipment (UE) in a wireless communication network according to various aspects of the present disclosure.

[0020] Figure 3 is a block diagram conceptually illustrating an example of a frame structure in a wireless communication network according to various aspects of the present disclosure.

[0021] Figure 4A A block diagram illustrating the use of rate splitting at a base station in accordance with various aspects of the present disclosure is shown.

[0022] Figure 4B A block diagram illustrating the use of rate splitting at a user equipment in accordance with various aspects of the present disclosure is shown.

[0023] Figure 5A A diagram 500A illustrating configuration type 1 of a demodulation reference signal (DM-RS) in accordance with various aspects of the present disclosure is shown.

[0024] Figure 5B A diagram 500B illustrating configuration type 2 of a DM-RS according to various aspects of the present disclosure is shown.

[0025] Fig. 6AShown is a diagram 600A illustrating various locations of additional DM-RS symbols for 1-symbol front-loaded DM-RS in accordance with various aspects of the present disclosure.

[0026] Figure 6B A diagram 600B is shown illustrating various locations of additional DM-RS symbols for 1-symbol front-loaded DM-RS in accordance with various aspects of the present disclosure.

[0027] Figure 6C A diagram 600C is shown illustrating various locations of additional DM-RS symbols for 1-symbol front-loaded DM-RS in accordance with various aspects of the present disclosure.

[0028] Fig.6D Shown is a diagram 600D illustrating various locations of additional DM-RS symbols for 2-symbol front-loaded DM-RS in accordance with various aspects of the present disclosure.

[0029] Figure 7 is a diagram illustrating an example process 700 performed at a user equipment (UE) in accordance with various aspects of the present disclosure.

[0030] Figure 8 A diagram 800 illustrating different DM-RS densities for different DM-RS ports in accordance with various aspects of the present disclosure is shown.

[0031] Fig. 9 is a diagram illustrating an example process 900 performed at a network entity in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0032] The various aspects of the present disclosure are described in more detail 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 so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings of this article, it should be understood by those skilled in the art that the scope of the present disclosure is intended to cover any aspect of the disclosure disclosed herein, whether it is implemented independently or in combination with any other aspect of the present disclosure. 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 a device or method practiced using other structures, functional functions, or structures and functionality in addition to the various aspects of the present disclosure given herein or different from the various aspects of the present disclosure given herein. It should be understood that any aspect of the disclosure disclosed herein can be implemented by one or more elements of the claims.

[0033] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be 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 may 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.

[0034] It should be noted that although various aspects are described herein using terms commonly associated with 3G and / or 4G wireless technologies, various aspects of the present disclosure may also be applicable to communication systems based on other generations (such as 5G and beyond, including NR technology and open RAN (O-RAN) technology).

[0035] Figure 1 is a diagram showing a wireless network 100 in which various aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network, a 5G or NR network, etc. The wireless network 100 may include several BSs 110 (shown as BS110a, BS110b, BS110c, and BS110d) and other network entities. A BS is an entity that communicates with a 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 receive point (TRP), etc. Each BS may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0036] 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., a radius of several kilometers) 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 home) 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 1In the example shown in , 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.

[0037] 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 transmit the 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, a relay station 110d may communicate with a macro BS 110a and a UE 120d to facilitate communication between the BS 110a and the UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay station, and the like.

[0038] The wireless network 100 may be a heterogeneous network including different types of BSs, such as a macro BS, a pico BS, a femto BS, a relay BS, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 watts 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 watt to 2 watts).

[0039] The network controller 130 may be coupled to one or more BSs (e.g., a set of BSs) and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via backhaul. The BSs may also communicate with each other (e.g., directly or indirectly via wireless or wired backhaul).

[0040] UEs 120 (e.g., 120a, 120b, 120c, 120d, 120e, etc.) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. The UE may communicate with one or more BSs in the wireless network 100, and may communicate via side links (e.g., Figure 1 150) with another UE (e.g., UE 120a and UE 120e, as shown in FIG. Figure 1 exemplified) direct communication, etc.

[0041] In some cases, two or more slave entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, nearby services, UE-to-network relays, vehicle-to-everything (V2X) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical grids, and / or various other suitable applications. Generally speaking, a sidelink signal may refer to a signal transmitted from one slave entity (e.g., UE1) to another slave entity (e.g., UE2) without the need for relaying the communication through a scheduling entity (e.g., UE or BS), even though the scheduling entity may be used for scheduling purposes and / or control purposes. In some examples, a licensed spectrum may be used to communicate sidelink signals (unlike wireless local area networks that may use unlicensed spectrum).

[0042] 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 smart phone), 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 device, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biometric sensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicle-mounted 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 medium or a wired medium.

[0043] Some UEs may be considered as machine type communication (MTC) UEs, or evolved or enhanced machine type communication (eMTC) UEs. For example, MTC and eMTC UEs include robots, drones, remote devices, sensors, meters, monitors, location tags, etc. that can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node (e.g., UE, BS, etc.) may provide, for example, a connection to a network (e.g., a wide area network such as the Internet or a cellular network) or a connection to a network via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (CPE). UE 120 may be included in a housing that houses components of UE 120 (e.g., processor components, memory components, etc.).

[0044] Generally speaking, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. In a given geographic area, each frequency can support a single RAT to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0045] As described herein, a wireless node (which may be referred to as a node, a network node, a network entity, or a wireless node) may include, may be, or may be included in (e.g., as a component of) a base station (e.g., any base station described herein), a UE (e.g., any UE described herein), a network controller, an apparatus, a device, a computing system, an integrated access and backhaul (IAB) node, a distributed unit (DU), a central unit (CU), a remote unit (RU), and / or another processing entity configured to perform any of the techniques described herein. For example, the network node may be a UE. As another example, the network node may be a base station or a network entity. As another example, a first network node may be configured to communicate with a second network node or a third network node. In one aspect of this example, the first network node may be a UE, the second network node may be a base station, and the third network node may be a UE. In another aspect of this example, the first network node may be a UE, the second network node may be a base station, and the third network node may be a base station. In yet other aspects of this example, the first network node, the second network node, and the third network node may be different relative to these examples. Similarly, references to UE, base station, device, equipment, computing system, etc. may include disclosure of UE, base station, device, equipment, computing system, etc. as network nodes. For example, a disclosure that a UE is configured to receive information from a base station also discloses that a first network node is configured to receive information from a second network node. Consistent with the present disclosure, once a specific example is expanded according to the present disclosure (e.g., a UE is configured to receive information from a base station also discloses that a first network node is configured to receive information from a second network node), a broader example of a narrower example may be interpreted conversely but in a broad, open-ended manner. In the above example that a UE is configured to receive information from a base station, it is also disclosed that a first network node is configured to receive information from a second network node, wherein the first network node may refer to a first UE, a first base station, a first device, a first device, a first computing system, a first group of one or more components, a first processing entity, etc. configured to receive information; and the second network node may refer to a second UE, a second base station, a second device, a second device, a second computing system, a second group of one or more components, a second processing entity, etc.

[0046] As described herein, different terms may be used in various aspects to describe the communication of information (e.g., any information, signal, etc.). The disclosure of one communication term includes the disclosure of other communication terms. For example, a first network node may be described as being configured to send information to a second network node. In this example and consistent with the present disclosure, when the first network node is configured to send information to the second network node, the first network node may be configured to provide, transmit, output, communicate, or send information to the second network node. Similarly, in this example and consistent with the present disclosure, when the first network node is configured to send information to the second network node, the second network node may be configured to receive, obtain, or decode information provided, transmitted, output, communicated, or sent by the first network node.

[0047] As indicated above, Figure 1 Provided as an example only. Other examples may vary from Figure 1 An example of description.

[0048] Figure 2 A block diagram of a design 200 of base station 110 and UE 120 is shown, which may be Figure 1 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.

[0049] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based on the MCS selected for each UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signals (PSS) and secondary synchronization signals (SSS)). The transmit (Tx) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., pre-decoding) on ​​data symbols, control symbols, overhead symbols, and reference symbols where applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 (e.g., 232a to 232t) may process a corresponding 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 up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively. According to various aspects described in more detail below, position coding may be used to generate synchronization signals to convey additional information.

[0050] At the UE 120, antennas 252a to 252r may receive downlink signals from the base station 110 and / or other base stations, and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 (e.g., 254a to 254r) 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 to 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120a to a data sink 260, and provide decoded control information and system information to a controller / processor 280. The channel processor may identify 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.

[0051] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be pre-decoded by a Tx MIMO processor 266, where applicable, further processed by modulators 254a to 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and sent on the uplink to the base station 110. At the base station 110, uplink signals from the UE 120 and / or other UEs may be received by antennas 234 (e.g., 234a to 234t), processed by demodulators 232, detected by MIMO detector 236, where applicable, and further processed by a receive processor 238 to obtain decoded data and control information transmitted by the UE 120a. The receive processor 238 may provide decoded data to a data sink 239 and decoded control information to a controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0052] The transmit processor 220 of the base station 110, the receive processor 238 of the base station 110, the transmit processor 264 of the UE 120, the receive processor 258 of the UE 120, and / or Figure 2 Any other components of the UE 120 may perform one or more techniques associated with encoding and / or decoding, as described in more detail elsewhere herein. For example, the transmit processor 220 of the base station 110, the receive processor 238 of the base station 110, the transmit processor 264 of the UE 120, the receive processor 258 of the UE 120, and / or Figure 2 Any other component of can perform or direct, for example, FIG. 4, Figure 5A , Figure 5B , Fig. 6A , Figure 6B , Figure 6C , Fig.6D or Figure 8 method, or Figure 7 or Fig. 9 The processes and / or operations of other methods and processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. Scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0053] In some aspects, UE 120 may include: a component for receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream; a component for determining a DM-RS configuration for the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and a component for receiving the downlink transmission based on the DM-RS configuration.

[0054] In some aspects, a network entity (e.g., base station 110) may include: a component for determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; a component for generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; a component for sending the DCI to a user equipment (UE); a component for generating the downlink transmission based on the DM-RS configuration; and a component for sending the downlink transmission to the UE.

[0055] As indicated above, Figure 2 This is provided as an example only. Other examples may differ from those described above. Figure 2 An example of description.

[0056] Figure 3 An example frame structure 300 for frequency division duplex (FDD) in a telecommunication system (e.g., LTE, 5G NR, etc.) is shown. The transmit timeline may be divided into units of radio frames, where t represents time. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be divided into a plurality of subframes with indices 0 to 2L-1. Each subframe may include two time slots. As an example, each radio frame may be divided into 10 subframes 0 to 9 and 20 time slots with indices 0 to 19. Each time slot may include a plurality of symbol periods, such as seven symbol periods for a normal cyclic prefix, or six symbol periods for an extended cyclic prefix.

[0057] In some aspects, a UE (e.g., UE 120a, etc.) may transmit one or more sidelink communications on a sidelink to another UE (e.g., UE 120a, etc.) in a transmission period that may include one or more time slots included in the frame structure 300. In some aspects, the other UE may receive the one or more sidelink communications, may generate feedback for the one or more sidelink communications, may incorporate the feedback into one or more feedback communications, and may transmit one or more feedback communications on a sidelink to the UE in one or more symbols and / or time slots included in a reporting period in the frame structure 300 configured for the sidelink.

[0058] Although some techniques are described herein in conjunction with frames, subframes, time slots, etc., these techniques may be equally applicable to other types of wireless communication structures, which may be referred to in 5G NR using terms other than "frames," "subframes," "time slots," etc. In some aspects, a wireless communication structure may refer to a periodic, time-bounded communication unit defined by a wireless communication standard and / or protocol.

[0059] As mentioned above, Figure 3 Provided as an example only. Other examples may vary from Figure 3 An example of description.

[0060] In some aspects of the disclosure, wireless nodes dispersed in wireless network 100, such as base station 110 and UE 120, may use rate division multiple access schemes in conjunction with appropriate design of reference signals to enhance wireless communications, for example, to achieve greater degrees of freedom and / or higher capacity.

[0061] Figure 4AA block diagram 400A illustrating the use of rate splitting at a base station according to various aspects of the present disclosure is shown. In some aspects, a base station 405 (e.g., any one of BS110) may wirelessly communicate with multiple individual users such as UE1 410a (e.g., any one of UE 120) and / or UE2 410b (e.g., any one of UE 120). More specifically, the base station 405 may intend to wirelessly send a message W1 to UE1 410a and / or wirelessly send a message W2 to UE 410b. In some aspects, messages W1 and W2 may correspond to respective transmission blocks destined for UE1 410a and UE410b, and may be processed and / or provided, for example, at a physical (PHY) layer of a reference model for wireless communication (e.g., an open system interconnection (OSI) model). Messages W1 and W2 may be obtained from a higher layer, or from a suitable previous processing stage in the PHY layer, and so on. In some aspects, messages W1 and W2 may correspond to a physical downlink shared channel (PDSCH) for respective UEs (e.g., UE1 410a and UE2 410b), etc. In some aspects, base station 405 may communicate with UEs 410a and 410b using multiple antennas 415 (e.g., any one of antennas 234a to 234t). In some aspects, antenna 415 may refer to antennas of one TRP, one gNB, etc. In other aspects, antenna 415 may refer to antennas of multiple TRPs, multiple gNBs, etc., such as in a coordinated multi-point (CoMP) scenario.

[0062] In some aspects, for example, at processing stage 420, a message W1 destined for UE1 410a may be divided into a common portion W 1,c and dedicated part W 1,p , and the message W2 designed for UE2 410b can be divided into a common part W 2,c and dedicated part W 2,p Processing stage 420 may be implemented by a portion of transmit processor 220 of base station 110 or any suitable component of base station 110, etc. In some aspects, the name “common” may refer to the portion that undergoes common encoding. 1,c and W 2,c (see below), and may not require W 1,c and W 2,c In some aspects, the corresponding common parts W of the messages W1 and W2 are the same. 1,c and W 2,c The messages may then be combined (eg, concatenated) in combiner 425 into a common message W c Similar to the above, the combiner 425 may be implemented by a portion of the transmit processor 220 of the base station 110 or any suitable component of the base station 110, etc.

[0063] In some aspects, for example, at processing stage 430, the message W 1,p , W c and W 2,p Each of these can be processed separately to obtain the corresponding streams X1, X c For example, the processing at the processing stage 430 may include channel decoding (e.g., using a low density parity check (LDPC) decoding scheme, etc.), rate matching and mapping to multiple modulation symbols according to an appropriate rate matching and modulation scheme, etc. Those skilled in the art will appreciate that obtaining the streams X1, X2 c and X2 in some aspects may additionally involve scrambling, interleaving, mapping to one or more layers, etc. Similar to above, processing stage 430 may be implemented by a portion of transmit processor 220 of base station 110 or any suitable component of base station 110, etc.

[0064] In some aspects, for example, in the pre-decoding block 435, the streams X1, X c Each of X1, X2 is processed (e.g., spatially processed) to be mapped to the multiple antennas 415. In some aspects, the processing at the precoding block 435 may involve applying the precoding matrices P1, Pc, and P2 to each respective stream X1, X2. c and X2 to obtain the (joint) signal X=P to be transmitted by the base station 405 (eg, by the antenna 415 of the base station 405) c X c +P1X1+P2X2. The pre-coding block 435 may be implemented by a portion of the Tx MIMO processor 230 of the base station 110 or any suitable component of the base station 110, etc.

[0065] In some aspects, the base station 405 may not signal the precoding matrices (e.g., matrices P1, Pc, and P2) to the UEs 410a and 410b, such that the processing applied at the precoding block 435 may be transparent to the UEs 410a and 410b. In other words, the channel matrix (which may sometimes be referred to as an effective channel, or for simplicity, a channel) perceived by the UE (e.g., UE1 410a or UE2 410b) may be the product of the corresponding precoding matrix applied by the base station 405 for a single stream and the actual wireless channel. For example, the channel matrix for common stream X perceived by UE1 410a may be the product of the corresponding precoding matrix applied by the base station 405 for a single stream and the actual wireless channel. c The channel can be expressed as H1P c, the channel perceived by UE1 410a for its own private flow X1 can be represented as H1P1, and the channel perceived by UE1 410a for the private flow X2 of UE2 410b can be represented as H1P2, where H1 can represent a channel representing the properties of the wireless channel between the base station 405 and UE1 410a (e.g., the actual channel or an estimate thereof). The transmission received by UE1 410a can be represented as Y1=H1P c X c +H1P1X1+H1P2X2+N1, where N1 may represent an imperfection in a wireless channel, e.g., related to UE1 410a, and may involve channel distortion, multipath effects, additive white Gaussian noise (AWGN), etc. Those skilled in the art will appreciate that corresponding considerations regarding UE1 410a may apply to UE2 410b, except that the channel between the base station 405 and UE2 410b may be represented by H2 (instead of H1).

[0066] Figure 4B A block diagram 400B illustrating the use of rate splitting at a user equipment according to various aspects of the present disclosure is shown. In some aspects, UE1 410a may wirelessly receive transmission Y1 from base station 405. In some aspects, for example, at processing stage 450, UE1 410a may perform channel estimation on the common stream (e.g., to obtain channel H1P c ) and / or perform channel estimation (CE) on the private stream (e.g., to obtain the channel H1P1). The processing stage 450 may be implemented by a portion of the MIMO detector 256 of the UE 120 and / or a portion of the receive processor 258 or any suitable component of the UE 120, etc. In some aspects, the channel estimation may be performed based on a reference signal associated with the corresponding stream. In some aspects, the channel estimation for the public stream may be performed based on a reference signal associated with the public stream (which may also be referred to as a reference signal for the public stream), while the channel estimation for the private stream may be performed based on a reference signal associated with the private stream (which may also be referred to as a reference signal for the private stream). In some aspects, the reference signal may correspond to a demodulation reference signal (DM-RS), such as a DM-RS for a PDSCH in 5G / NR, etc. In some aspects, in addition, the transmission received by the UE1 410a (e.g., transmission Y1) may be additionally processed at the UE1 410a, such as processing reverse rate matching, demapping bits and modulation symbols, descrambling, deinterleaving, reverse layer mapping, etc.

[0067] In some aspects, for example, in processing block 455, the received transmission Y1 may be decoded to obtain the common message W c , which includes a common part W for UE1 410a 1,cand a common portion W for UE2 410b 2,c In some aspects, processing block 455 may be performed upon decoding the received transmission Y1 to obtain the common message W c The common stream (eg, channel H1P) determined at processing stage 450 is considered. c ) channel estimate. Processing block 455 may be implemented by a portion of MIMO detector 256 of UE 120 and / or a portion of receive processor 258 or any suitable component of UE 120, etc. After successful decoding, in some aspects, for example, in processing block 460, the public message W c Can be used to reconstruct public stream X c , so that it can be subtracted from the received transmission Y1 (see below). For example, the common message W can be processed in processing block 455 of UE1 410a c , similar to the processing of the common message W at the processing stage 430 of the base station 405 c Processing block 460 may be implemented by a portion of MIMO detector 256 and / or a portion of receive processor 258 of UE 120, or any suitable component of UE 120, among others.

[0068] In some aspects, for example, in process block 465, the reconstructed common stream X c can be used to subtract a signal representing the common stream (e.g., H1P1X) from the received transmission Y1 c ) to obtain the special message W that will be used to decode 1,p signal Y 1,p (See below). Signal Y 1,p can be obtained in processing block 465, so that Y 1,p =Y1-H1P c X c Those skilled in the art will appreciate that assuming the channel estimate H1P c is sufficient, then the signal Y 1,p It can be expressed as Y 1,p =H1P1X1+H1P2X2+N1, and thus can facilitate obtaining the dedicated message W at UE1410a 1,p Processing block 465 may be implemented by a portion of MIMO detector 256 and / or a portion of receive processor 258 of UE 120, or any suitable component of UE 120, etc. In some aspects, for example, in processing block 470, signal Y 1,p can then be decoded to obtain a dedicated message W for UE1 410a 1,p In some aspects, processing block 470 may be performed after decoding signal Y 1,p To get the message W 1,pThe channel estimate for the private stream (eg, channel H1P1) determined at processing stage 450 is considered. Processing block 470 may be implemented by a portion of MIMO detector 256 and / or a portion of receive processor 258 of UE 120 or any suitable component of UE 120, etc.

[0069] After successful decoding, in some aspects, UE1 410a may combine (eg, concatenate) the common portion W for UE1 410a. 1,c and a dedicated message W for UE1 410a 1,p To obtain the dedicated message W1. Those skilled in the art will appreciate that the processing explained in conjunction with blocks 450, 455, 460, 465, and 470 may sometimes be referred to as successive interference cancellation (SIC). Alternatively, the processing explained in conjunction with block 455 may include at least demodulation, but may not necessarily include decoding. For example, in some aspects, the public message W c It is not necessary to include a common portion destined for a specific UE (e.g., UE1 410a). This can be applicable to various scenarios involving two or more UEs. In this case, the signal Y as described above is obtained. 1,p , or jointly demodulating the public and private streams can reduce interference and thus facilitate decoding of dedicated messages W 1,p .

[0070] Those skilled in the art will appreciate that for a common stream (eg, channel H1P c ) and / or private streams (eg, channels H1P1) may be beneficial in improving the ability to successfully decode public messages W destined for UE1 410a. c and / or its common parts 1,c In addition or alternatively, a suitable channel estimate for the common stream (eg, channel H1P c ) may be useful for reconstructing the public message W c (e.g., in processing blocks 460 and 465) in order to perform SIC. Those skilled in the art will appreciate that appropriate design of reference signals can facilitate obtaining channel estimates for common streams and / or for private streams. In some aspects, for common streams and / or for private streams, the design of reference signals (e.g., DM-RS) can, for example, involve configuration of one or more ports (e.g., one or more DM-RS ports), one or more code division multiplexing (CDM) groups, one or more sequences (e.g., DM-RS sequences) and / or one or more identifiers for initializing corresponding sequences, density and / or location of reference signals in an orthogonal frequency division multiplexing (OFDM) resource grid, and / or the like.

[0071] As mentioned above, Figure 4A and Figure 4B Provided as an example only. Other examples may vary from Figure 4A or Figure 4B An example of description.

[0072] In some aspects, a base station (eg, base station 405) may be configured to provide a common flow (eg, common flow X) to a base station. c ) and a private stream (e.g., a private stream X1 destined for UE1 410a) provide separate reference signals such as separate demodulation reference signals (DM-RS) to facilitate obtaining corresponding channel estimates (e.g., channel H1P) at the UE (e.g., UE1 410a). c and / or channel H1P1).

[0073] Figure 5A A diagram 500A is shown illustrating configuration type 1 of a demodulation reference signal (DM-RS) according to various aspects of the present disclosure. In some aspects, for example, in 5G / NR, etc., two DM-RS modes may be defined: configuration type 1 (which may also be referred to as Config Type 1) and configuration type 2 (which may also be referred to as Config Type 2). In some aspects, configuration type 1 may involve mapping a DM-RS port to every other subcarrier in an OFDM symbol. For example, Figure 5A As shown in the various diagrams of , the DM-RS port corresponding to PDSCH port 1000 can be mapped to subcarriers 0, 2, 4, 6, 8, and 10 of a resource block (RB), while the DM-RS port corresponding to PDSCH port 1002 can be mapped to subcarriers 1, 3, 5, 7, 9, and 11 of the RB, and so on. In some aspects, the DM-RS pattern may include one or two OFDM symbols. For example, the configuration type 1 pattern may occupy only one OFDM symbol, as shown in diagram 510, or it may occupy two OFDM symbols, as shown in diagram 520. In some aspects, only one OFDM symbol (or two OFDM symbols) carrying DM-RS may be located in the first (or first two) OFDM symbols of the PDSCH and may be referred to as front-loading DM-RS. Alternatively, in some aspects, only one OFDM symbol (or two OFDM symbols) carrying DM-RS may be located in OFDM symbol #2 (or OFDM symbols #2 and #3) of a slot, regardless of the location of the PDSCH in the slot. In some aspects, in addition to front-loading DM-RS, additional symbols including DM-RS may be configured (as described below in conjunction with Fig. 6A , Figure 6B , Figure 6C and Fig.6D explained).

[0074] In some aspects, for example, in 5G / NR, etc., antenna ports carrying one or more PDSCHs (and / or DM-RS ports corresponding to corresponding PDSCHs) may be indicated by a base station (e.g., base station 110, base station 405) to a UE (e.g., UE 120, UE1 410a, UE2 410b) in one or more fields of downlink control information (DCI) that schedules one or more PDSCHs (directly or indirectly). In some aspects, for example, in 5G / NR, etc., the DCI may be included in one or more physical downlink control channels (PDCCHs).

[0075] In some aspects, such as in 5G / NR, etc., DM-RS ports may be divided into code division multiplexing (CDM) groups. For example, two CDM groups may be defined for configuration type 1, while three CDM groups may be defined for configuration type 2 (hereinafter combined with Figure 5B Explanation). In some aspects, within a CDM group, different DM-RS ports may occupy the same set of resource elements (REs) and may be separated by using different orthogonal cover codes (OCCs). In some aspects, across CDM groups, DM-RS ports may be separated by using frequency division multiplexing (FDM) so that DM-RS REs may be separated in the frequency domain. For example, as shown in diagram 510, DM-RS ports corresponding to PDSCH ports 1000 and 1001 may form a CDM group and may therefore occupy the same REs and may be separated by different OCCs. Similar considerations may apply to DM-RS ports corresponding to PDSCH ports 1002 and 1003 forming a second CDM group. In addition, for example, as shown in diagram 520, DM-RS ports corresponding to PDSCH ports 1000, 1001, 1004, and 1005 may form a CDM group and may therefore occupy the same REs and may be separated by different OCCs. Similar considerations may apply to the DM-RS ports corresponding to the PDSCH ports 1002, 1003, 1006, and 1007 forming the second CMD group. In some aspects, for example, as illustrated in diagram 530, the four DM-RS patterns may be orthogonal (in the frequency domain and the time domain, respectively) in a group of REs comprising 2×2 REs.

[0076] In some aspects, for example, in 5G / NR, etc., a sequence (e.g., a DM-RS sequence) sent on a DM-RS port may be determined based on a CDM group (e.g., per CDM group). In some aspects, for example, in 5G / NR Release 15, the same sequence may be used in DM-RS REs of different CDM groups (which may be located in different REs). In other aspects, for example, in 5G / NR Release 16, different sequences may be used in DM-REs of different CDM groups by using different initializations (e.g., different pseudo noise (PN) sequence initializations).

[0077] Figure 5B A diagram 500B is shown illustrating a configuration type 2 of a demodulation reference signal (DM-RS) according to various aspects of the present disclosure. In some aspects, configuration type 2 may involve mapping a DM-RS port to two consecutive REs in a group of six REs in an RB (i.e., using a gap of four REs). For example, Figure 5B As shown in the various diagrams of , the DM-RS port corresponding to PDSCH port 1000 can be mapped to subcarriers 0, 1, 6, and 7 of the RB, while the DM-RS port corresponding to PDSCH port 1002 can be mapped to subcarriers 2, 3, 8, and 9 of the RB, and the DM-RS port corresponding to PDSCH port 1004 can be mapped to subcarriers 4, 5, 10, and 11 of the RB, and so on. Similar to the above combined Figure 5A In the case of configuration type 1 explained above, in some aspects, the DM-RS pattern of configuration type 2 may include one or two OFDM symbols. For example, the configuration type 2 pattern may occupy only one OFDM symbol, as shown in diagram 550, or it may occupy two OFSM symbols, as shown in diagram 560. In some aspects, only one OFDM symbol (or two OFDM symbols) carrying DM-RS may be located in the first (or first two) OFDM symbols of the PDSCH and may be referred to as front-loading DM-RS. Alternatively, in some aspects, only one OFDM symbol (or two OFDM symbols) carrying DM-RS may be located in OFDM symbol #2 (or OFDM symbols #2 and #3) of a time slot, regardless of the position of the PDSCH in the time slot. In some aspects, in addition to front-loading DM-RS, additional symbols including DM-RS may also be configured (as described below in conjunction with Fig. 6A , Figure 6B , Figure 6C and Fig.6D explained).

[0078] In some aspects, for example, in 5G / NR, etc., antenna ports carrying one or more PDSCHs (and / or DM-RS ports corresponding to corresponding PDSCHs) may be indicated by a base station (e.g., BS110, base station 405) to a UE (e.g., UE 120, UE1410a, UE2 410b) in one or more fields of downlink control information (DCI) that schedules one or more PDSCHs (directly or indirectly). In some aspects, for example, in 5G / NR, etc., the DCI may be included in one or more physical downlink control channels (PDCCHs).

[0079] In some aspects, similar to the case of configuration type 1, in some aspects, such as in 5G / NR, etc., the DM-RS ports may be divided into code division multiplexing (CDM) groups. In some aspects, three CDM groups may be defined for configuration type 2. For example, as shown in diagram 550, the DM-RS ports corresponding to PDSCH ports 1000 and 1001 may form a CDM group, and thus may occupy the same RE and may be separated by different OCCs. Similar considerations may be applied to the DM-RS ports corresponding to PDSCH ports 1002 and 1003 forming the second CDM group, and the DM-RS ports corresponding to PDSCH ports 1004 and 1005 forming the third CDM group. In addition, for example, as shown in diagram 560, the DM-RS ports corresponding to PDSCH ports 1000, 1001, 1006, and 1007 may form a CDM group, and thus may occupy the same RE and may be separated by different OCCs. Similar considerations may apply to the DM-RS ports corresponding to the PDSCH ports 1002, 1003, 1008, and 1009 forming the second CDM group, and the DM-RS ports corresponding to the PDSCH ports 1004, 1005, 1010, and 1011 forming the third CDM group. In some aspects, for example, as illustrated in diagram 570, the four DM-RS patterns may be orthogonal (in the frequency domain and in the time domain, respectively) in a group of REs comprising 2×2 REs.

[0080] In some aspects, similar to the case of configuration type 1, in some aspects, such as in 5G / NR, etc., the sequence (e.g., DM-RS sequence) sent on the DM-RS port can be determined based on the CDM group (e.g., per CDM group). In some aspects, such as in 5G / NR Release 15, the same sequence can be used in DM-RS REs of different CDM groups (which can be located in different REs). In other aspects, such as in 5G / NR Release 16, different sequences can be used in DM-REs of different CDM groups by using different initializations (e.g., different pseudo-noise (PN) sequence initializations). In addition, in some aspects, the DM-RS ports corresponding to PDSCH ports 1006-1011 can be scheduled for UEs (e.g., UE1 410a) served on the same CDM group and co-scheduled UEs (e.g., including UE2 410b). In this case, there may be no phase tracking reference signal (PT-RS) for the UE receiving the corresponding PDSCH.

[0081] As mentioned above, Figure 5A and Figure 5B Provided as an example only. Other examples may vary from Figure 5A or Figure 5B An example of description.

[0082] Fig. 6A A diagram 600A is shown illustrating various locations of additional DM-RS symbols for 1-symbol front-loaded DM-RS according to various aspects of the present disclosure. In various examples explained below, within one resource block (RB), for example, in 5G / NR, etc., the front-loaded DM-RS may be located only in 1 symbol (e.g., in the first symbol of the PDSCH in the RB), and the additional DM-RS may be located only in 1 symbol with a varying position. In some aspects, such varying positions may depend on the configuration and / or number of symbols in the PDSCH. In some aspects, the pattern (e.g., assigned to subcarriers and / or CDM groups) and / or ports (e.g., DM-RS ports and / or PDSCH ports) of the additional DM-RS may be the same as the front-loaded DM-RS.

[0083] In some aspects, for example, as shown in diagram 602, the PDSCH may be scheduled (e.g., by base station 110, base station 405, etc.) to start in symbol #2 and end in symbol #8. In this example, the front-loaded DM-RS may be located in symbol #2 (which is the first symbol of the PDSCH), and the additional DM-RS may be located in symbol #7. In another example, as shown in diagram 604, the PDSCH may be scheduled to start in symbol #2 and end in symbol #9. In this example, the front-loaded DM-RS may be located in symbol #2, and the additional DM-RS may be located in symbol #9. In yet another example, as shown in diagram 606, the PDSCH may be scheduled to start in symbol #2 and end in symbol #10. In this example, the front-loaded DM-RS may be located in symbol #2, and the additional DM-RS may be located in symbol #9. In yet another example, as shown in diagram 608, the PDSCH may be scheduled to start in symbol #2 and end in symbol #11. In this example, the front-loaded DM-RS may be located in symbol #2, and the additional DM-RS may be located in symbol #9. In yet another example, as shown in diagram 610, the PDSCH may be scheduled to start in symbol #2 and end in symbol #12. In this example, the front-loaded DM-RS may be located in symbol #2, and the additional DM-RS may be located in symbol #11. In yet another example, as shown in diagram 612, the PDSCH may be scheduled to start in symbol #2 and end in symbol #13. In this example, the front-loaded DM-RS may be located in symbol #2, and the additional DM-RS may be located in symbol #11.

[0084] In another example, as shown in diagram 614, the PDSCH may be scheduled to start in symbol #3 and end in symbol #8. In this example, the front-loaded DM-RS may be located in symbol #3, and the additional DM-RS may be located in symbol #7. In yet another example, as shown in diagram 616, the PDSCH may be scheduled to start in symbol #3 and end in symbol #9. In this example, the front-loaded DM-RS may be located in symbol #3, and the additional DM-RS may be located in symbol #9. In yet another example, as shown in diagram 618, the PDSCH may be scheduled to start in symbol #3 and end in symbol #10. In this example, the front-loaded DM-RS may be located in symbol #3, and the additional DM-RS may be located in symbol #9. In yet another example, as shown in diagram 620, the PDSCH may be scheduled to start in symbol #3 and end in symbol #11. In this example, the front-loaded DM-RS may be located in symbol #3, and the additional DM-RS may be located in symbol #9. In yet another example, as shown in diagram 622, the PDSCH may be scheduled to start in symbol #3 and end in symbol #12. In this example, the front-loaded DM-RS may be located in symbol #3, and the additional DM-RS may be located in symbol #11. In yet another example, as shown in diagram 624, the PDSCH may be scheduled to start in symbol #3 and end in symbol #13. In this example, the front-loaded DM-RS may be located in symbol #3, and the additional DM-RS may be located in symbol #11.

[0085] Figure 6B A diagram 600B is shown illustrating various locations of additional DM-RS symbols for 1-symbol front-loaded DM-RS according to various aspects of the present disclosure. In various examples explained below, within one resource block (RB), for example, in 5G / NR, etc., the front-loaded DM-RS may be located only in 1 symbol (e.g., in the first symbol of the PDSCH in the RB), and the additional DM-RS may be located (precisely) in 2 symbols with varying positions. In some aspects, such varying positions may depend on the configuration and / or number of symbols in the PDSCH. In some aspects, the pattern (e.g., assigned to subcarriers and / or CDM groups) and / or ports (e.g., DM-RS ports and / or PDSCH ports) of the additional DM-RS may be the same as the front-loaded DM-RS.

[0086] In some aspects, for example, as shown in diagram 630, the PDSCH may be scheduled (e.g., by base station 110, base station 405, etc.) to start in symbol #2 and end in symbol #9. In this example, the front-loaded DM-RS may be located in symbol #2 (i.e., in the first symbol of the PDSCH), and the two additional DM-RSs each located in one symbol may be located in symbol #6 and symbol #9, respectively. In another example, as shown in diagram 632, the PDSCH may be scheduled to start in symbol #2 and end in symbol #10. In this example, the front-loaded DM-RS may be located in symbol #2, and the two additional DM-RSs each located in one symbol may be located in symbol #6 and symbol #9, respectively. In yet another example, as shown in diagram 634, the PDSCH may be scheduled to start in symbol #2 and end in symbol #11. In this example, the front-loaded DM-RS may be located in symbol #2, and the two additional DM-RSs each located in one symbol may be located in symbol #6 and symbol #9, respectively. In yet another example, as shown in diagram 636, the PDSCH may be scheduled to start in symbol #2 and end in symbol #12. In this example, the front-loaded DM-RS may be located in symbol #2, and two additional DM-RSs each located in one symbol may be located in symbol #7 and symbol #11, respectively. In yet another example, as shown in diagram 638, the PDSCH may be scheduled to start in symbol #2 and end in symbol #13. In this example, the front-loaded DM-RS may be located in symbol #2, and two additional DM-RSs each located in one symbol may be located in symbol #7 and symbol #11, respectively.

[0087] In another example, as shown in diagram 640, the PDSCH may be scheduled to start in symbol #3 and end in symbol #9. In this example, the front-loaded DM-RS may be located in symbol #3, and the two additional DM-RSs each located in one symbol may be located in symbol #6 and symbol #9, respectively. In yet another example, as shown in diagram 642, the PDSCH may be scheduled to start in symbol #3 and end in symbol #10. In this example, the front-loaded DM-RS may be located in symbol #3, and the two additional DM-RSs each located in one symbol may be located in symbol #6 and symbol #9, respectively. In yet another example, as shown in diagram 644, the PDSCH may be scheduled to start in symbol #3 and end in symbol #11. In this example, the front-loaded DM-RS may be located in symbol #3, and the two additional DM-RSs each located in one symbol may be located in symbol #6 and symbol #9, respectively. In yet another example, as shown in diagram 646, the PDSCH may be scheduled to start in symbol #3 and end in symbol #12. In this example, the front-loaded DM-RS may be located in symbol #3, and two additional DM-RSs each located in one symbol may be located in symbol #7 and symbol #11, respectively. In yet another example, as shown in diagram 648, the PDSCH may be scheduled to start in symbol #3 and end in symbol #13. In this example, the front-loaded DM-RS may be located in symbol #3, and two additional DM-RSs each located in one symbol may be located in symbol #7 and symbol #11, respectively.

[0088] Figure 6C A diagram 600C is shown illustrating various locations of additional DM-RS symbols for 1-symbol front-loaded DM-RS according to various aspects of the present disclosure. In various examples explained below, within one resource block (RB), for example, in 5G / NR, etc., the front-loaded DM-RS may be located in only 1 symbol (e.g., in the first symbol of the PDSCH in the RB), and the additional DM-RS may be located in (exactly) 3 symbols with varying locations. In some aspects, such varying locations may depend on the configuration and / or number of symbols in the PDSCH. In some aspects, the pattern (e.g., assigned to subcarriers and / or CDM groups) and / or ports (e.g., DM-RS ports and / or PDSCH ports) of the additional DM-RS may be the same as the front-loaded DM-RS.

[0089] In some aspects, for example, as shown in diagram 650, the PDSCH may be scheduled (e.g., by base station 110, base station 405, etc.) to start in symbol #2 and end in symbol #11. In this example, the front-loaded DM-RS may be located in symbol #2 (i.e., in the first symbol of the PDSCH), and the three additional DM-RSs each located in one symbol may be located in symbol #5, symbol #8, and symbol #11, respectively. In another example, as shown in diagram 652, the PDSCH may be scheduled to start in symbol #2 and end in symbol #12. In this example, the front-loaded DM-RS may be located in symbol #2, and the three additional DM-RSs each located in one symbol may be located in symbol #5, symbol #8, and symbol #11, respectively. In yet another example, as shown in diagram 654, the PDSCH may be scheduled to start in symbol #2 and end in symbol #13. In this example, the front-loaded DM-RS may be located in symbol #2, and three additional DM-RSs, each located in one symbol, may be located in symbol #5, symbol #8, and symbol #11, respectively.

[0090] Fig.6D A diagram 600D is shown illustrating various locations of additional DM-RS symbols for 2-symbol front-loaded DM-RS according to various aspects of the present disclosure. In various examples explained below, within a resource block (RB), for example, in 5G / NR, etc., the front-loaded DM-RS can be (precisely) located in 2 symbols (e.g., in the first symbol and second symbol of the PDSCH in the RB), and the additional 2-symbol DM-RS can be located in a varying 2-symbol position. In some aspects, such varying positions can depend on the configuration and / or number of symbols in the PDSCH. In some aspects, the pattern (e.g., assigned to subcarriers and / or CDM groups) and / or ports (e.g., DM-RS ports and / or PDSCH ports) of the additional DM-RS can be the same as the front-loaded DM-RS.

[0091] In some aspects, for example, as shown in diagram 660, the PDSCH may be scheduled (e.g., by base station 110, base station 405, etc.) to start in symbol #2 and end in symbol #9. In this example, the 2-symbol front-loading DM-RS may be located in symbols #2 and #3 (i.e., in the first and second symbols of the PDSCH), and the additional 2-symbol DM-RS may be located in symbols #8 and #9. In another example, as shown in diagram 662, the PDSCH may be scheduled to start in symbol #2 and end in symbol #10. In this example, the 2-symbol front-loading DM-RS may be located in symbols #2 and #3, and the additional 2-symbol DM-RS may be located in symbols #8 and #9. In yet another example, as shown in diagram 664, the PDSCH may be scheduled to start in symbol #2 and end in symbol #11. In this example, the 2-symbol front-loading DM-RS may be located in symbols #2 and #3, and the additional 2-symbol DM-RS may be located in symbols #8 and #9. In yet another example, as shown in diagram 666, the PDSCH may be scheduled to start in symbol #2 and end in symbol #12. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #2 and #3, and the additional 2-symbol DM-RS may be located in symbols #10 and #11. In yet another example, as shown in diagram 668, the PDSCH may be scheduled to start in symbol #2 and end in symbol #13. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #2 and #3, and the additional 2-symbol DM-RS may be located in symbols #10 and #11.

[0092] In another example, as shown in diagram 670, the PDSCH may be scheduled to start in symbol #3 and end in symbol #9. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #3 and #4, and the additional 2-symbol DM-RS may be located in symbols #8 and #9. In yet another example, as shown in diagram 672, the PDSCH may be scheduled to start in symbol #3 and end in symbol #10. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #3 and #4, and the additional 2-symbol DM-RS may be located in symbols #8 and #9. In yet another example, as shown in diagram 674, the PDSCH may be scheduled to start in symbol #3 and end in symbol #11. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #3 and #4, and the additional 2-symbol DM-RS may be located in symbols #8 and #9. In yet another example, as shown in diagram 676, the PDSCH may be scheduled to start in symbol #3 and end in symbol #12. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #3 and #4, and the additional 2-symbol DM-RS may be located in symbols #10 and #11. In yet another example, as shown in diagram 678, the PDSCH may be scheduled to start in symbol #3 and end in symbol #13. In this example, the 2-symbol front-loaded DM-RS may be located in symbols #3 and #4, and the additional 2-symbol DM-RS may be located in symbols #10 and #11.

[0093] As mentioned above, Fig. 6A , Figure 6B , Figure 6C and Fig.6D Provided as an example only. Other examples may vary from Fig. 6A , Figure 6B , Figure 6C and Fig.6D An example of description.

[0094] Based on the above and / or other considerations, those skilled in the art will appreciate that for rate division multiple access, it may be advantageous for the UE to know which DM-RS ports correspond to the public stream and which DM-RS ports correspond to the private stream destined for the UE. In addition, in some aspects, the DM-RS ports for private streams destined for different UEs may be the same. In this case, a network entity (e.g., base station 110, base station 405, etc.) may assign different sequences (e.g., DM-RS sequences) to these DM-RS ports. In addition, in some aspects, the DM-RS ports and DM-RS sequences for the public stream may be the same for different UEs. In this case, for a given UE, it may be advantageous (and / or only possible in the above case) for the CDM group of one or more DM-RS ports for the public stream to be different from the CDM group of one or more DM-RS ports for the private stream.

[0095] In addition, in some aspects, such as in 5G / NR, etc., the density of DM-RS in the OFDM grid (e.g., in terms of the number of subcarriers carrying DM-RS, the number of symbols carrying DM-RS, etc.) can be the same for all DM-RS ports. Based on the above and / or other considerations, those skilled in the art will appreciate that for rate division multiple access, for common streams (e.g., channels H1P c ), e.g., decoding and / or reconstructing the common message and / or portions thereof. In this case, for example, it may be advantageous to design the DM-RS to enable different DM-RS densities for different DM-RSs (e.g., in the time domain and / or frequency domain) for DM-RS ports associated with the common streams relative to DM-RS ports associated with one or more private streams destined for the respective UEs.

[0096] Figure 7 is a diagram illustrating an example process 700 performed at a user equipment (UE) in accordance with various aspects of the present disclosure. In some aspects, the UE may include (or may be) UE 120, UE1 410a, UE2 410b, etc. In some aspects, process 700 may be implemented by a portion of the MIMO detector 256 and / or a portion of the receive processor 258 of UE 120, or any suitable component of UE 120, UE1 410a, UE2 410b, etc. In some aspects, process 700 may include Figure 7 The blocks depicted in the process 700 may include additional blocks, fewer blocks, different blocks, or blocks arranged in a different manner than those depicted in the process 700. Additionally or alternatively, two or more blocks in the blocks of process 700 may be executed in parallel.

[0097] like Figure 7As shown, process 700 may include receiving downlink control information (DCI) for downlink transmission from a network entity (block 710). The downlink transmission may be based on a rate division multiple access scheme. The downlink transmission may include a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and a DM-RS for the private stream. In some aspects, the network entity may include base station 110, base station 405, etc. In some aspects, the rate division multiple access scheme may include (or may be) the above combined Figure 4B The rate split described herein may include its individual features. In some aspects, the common stream may include (or may be) a jointly coded stream destined for multiple UEs, such as the stream W described above. c . In some aspects, the common stream may include (or may be) a first PDSCH, a first set of layers of a PDSCH, and the like. The DM-RS for the common stream may include (or may be) a DM-RS associated with the first PDSCH or a first set of layers of a PDSCH. In some aspects, the private stream may include (or may be) a stream destined only for a UE performing example process 700. In some aspects, the private stream may include (or may be) a second PDSCH, a second set of layers of a PDSCH, and the like. The DM-RS for the private stream may include (or may be) a DM-RS associated with a second PDSCH or a second set of layers of a PDSCH. In some aspects, the DCI may include (or may be) the above in combination with Figure 5A or Figure 5B The DCI described herein may include individual features thereof. In some aspects, the DCI may schedule a first PDSCH or a first set of layers of a PDSCH, a second PDSCH or a second set of layers of a PDSCH, etc. The DCI may be included in one or more PDCCHs.

[0098] like Figure 7 As further shown, in some aspects, the process 700 may include determining a DM-RS configuration for a DM-RS for a public stream and a DM-RS for a private stream based on the DCI (block 720). The DM-RS configuration may include (or may be equal to) any one or more of the aspects described herein and / or similar aspects that may facilitate receiving a DM-RS for a public stream and / or a DM-RS for a private stream. The corresponding DM-RS configuration for the public stream and / or the private stream may include (or may be) one or more DM-RS ports, a code division multiplexing (CDM) group associated with the DM-RS port, a DM-RS sequence, an identifier for initializing a DM-RS sequence, a density of DM-RS in an orthogonal frequency division multiplexing (OFDM) resource grid, etc., or any combination thereof. Determining a DM-RS configuration may refer to any one or more of the activities described herein and / or similar activities that result in obtaining a DM-RS configuration.

[0099] In addition, if Figure 7 As shown, in some aspects, process 700 may include receiving a downlink transmission based on the DM-RS configuration (block 730). In some aspects, the received downlink transmission may also be used in accordance with any one or more of the aspects described herein, etc. For example, in some aspects, a determination may be made based on the downlink transmission (e.g., based on the DM-RS for the public stream and / or the DM-RS for the private stream) to determine whether to allocate a downlink transmission to a public stream (e.g., channel H1P). c ) and / or channel estimates for private streams (eg, channel HP1). In addition, in some aspects, channel estimates for public streams and / or for private streams can be used for decoding, reconstruction, etc., as described herein.

[0100] In one or more aspects of the present disclosure, in process 700, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports for DM-RS for a public stream, one or more DM-RS ports for DM-RS for a private stream, or a combination thereof. In these aspects, one or more fields in the DCI may indicate one or more DM-RS ports for DM-RS for a public stream, one or more DM-RS ports for DM-RS for a private stream, or a combination thereof. For example, the DCI may explicitly indicate one or more DM-RS ports for corresponding DM-RS for a public stream and / or a private stream. In other examples, the DCI may indicate an antenna port associated with a PDSCH (or multiple PDSCHs), and one or more DM-RS ports may be derived from the antenna port (e.g., based on a one-to-one mapping between a DM-RS port and an antenna port associated with the PDSCH, etc.). Such a signaling scheme may, for example, facilitate flexibility and / or efficient processing at a UE.

[0101] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports for DM-RS for a public stream, one or more DM-RS ports for DM-RS for a private stream, or a combination thereof. In addition, in these aspects, one or more fields in the DCI may indicate a set of DM-RS ports for downlink transmission, the number of layers for a public stream, and the number of layers for a private stream. In addition, in these aspects, in process 700, determining the DM-RS configuration may also include: determining one or more DM-RS ports for DM-RS for a public stream as a first subset of the number of elements of the group of DM-RS ports equal to the number of layers for the public stream, and determining one or more DM-RS ports for DM-RS for a private stream as a second subset of the number of elements of the group of DM-RS ports equal to the number of layers for the private stream. For example, the DCI may indicate that the number of corresponding layers for the public stream and the private stream is 2 and 3, respectively, and may indicate DM-RS ports 0 to 4 (i.e., {0,1,2,3,4}) for the public stream and the private stream. In this case, the UE may determine DM-RS ports {0,1} as ports for DM-RS for a common stream based on the DCI, and DM-RS ports {2,3,4} as ports for DM-RS for a private stream. In other words, the UE may determine the first n ports in the indicated group of ports as ports for DM-RS for a common stream (where n corresponds to the number of layers indicated for the common stream), and determine the remaining m ports in the indicated group of ports as ports for DM-RS for a private stream (where m corresponds to the number of layers indicated for the private stream). Such a scheme may facilitate efficient signaling, for example, in terms of overhead and flexibility.

[0102] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports for DM-RS for a common stream, one or more DM-RS ports for DM-RS for a private stream, or a combination thereof. In addition, in these aspects, the first one or more fields in the DCI may indicate the presence of a common stream in a downlink transmission and a set of DM-RS ports for downlink transmission. In addition, in these aspects, in process 700, determining the DM-RS configuration may also include: determining a first subset of the set of DM-RS ports as one or more DM-RS ports for DM-RS for a common stream based on the indicated presence of a common stream; and determining a second subset of the set of DM-RS ports as one or more DM-RS ports for DM-RS for a private stream based on the indicated presence of a common stream. For example, the DCI may (explicitly or implicitly) indicate the presence of a common stream and indicate a set of DM-RS ports as {0,2,3}. In this case, the UE may determine the DM-RS port {0} as the port for the DM-RS for the public stream based on the DCI, and determine the DM-RS port {2,3} as the port for the DM-RS for the private stream. In other words, the UE may determine the first n ports (where n corresponds to the number of ports fixed in the standard, the number of ports preconfigured, or the number of ports determined according to a rule—see below) in the indicated group of ports as the ports for the DM-RS for the public stream, and determine the remaining ports in the indicated group of ports as the ports for the DM-RS for the private stream. Such a scheme may facilitate efficient signaling, for example, in terms of overhead and flexibility.

[0103] Additionally, in one or more of the above aspects, in process 700, a second one or more fields in the DCI may indicate the number of layers used for downlink transmission. Additionally, in these aspects, the first subset is also determined based on the number of layers. In some aspects, the second one or more fields in the DCI may be the same as the first one or more fields in the DCI, while in other aspects, the second one or more fields in the DCI may be different from the first one or more fields in the DCI, depending on the circumstances. In some aspects, for example, the second one or more fields in the DCI may indicate that the number of layers used for downlink transmission is L. In these aspects, the number of ports in the indicated first number of the set of ports may be determined as a function of the indicated number of layers L, for example, as The symbol Represents the "bottom layer" operation on x. In some alternatives, the second one or more fields in the DCI may not be present in the DCI, and L may represent the number of ports (e.g., DM-RS ports). Such a scheme may facilitate efficient signaling, for example, in terms of overhead and flexibility.

[0104] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports for DM-RS for a public stream, one or more DM-RS ports for DM-RS for a private stream, or a combination thereof. In addition, in these aspects, one or more fields in the DCI may indicate a group of DM-RS ports for downlink transmission. In addition, in these aspects, in process 700, determining the DM-RS configuration may also include: determining multiple CDM groups based on the group of DM-RS ports, each CDM group corresponding to a single DM-RS port in the group of DM-RS ports; determining a first subset of the group of DM-RS ports as one or more DM-RS ports for DM-RS for a public stream based on multiple CDM groups; and determining a second subset of the group of DM-RS ports as one or more DM-RS ports for DM-RS for a private stream based on multiple CDM groups. For example, the DCI may indicate a group of DM-RS ports as {0,1,2}. In this case, as described above, assuming that DM-RS port {0,1} may be in CDM group 0 and DM-RS port {2} may be in CDM group 1, the UE may determine DM-RS port {2} as the port for the DM-RS for the public stream, and determine DM-RS port {0,1} as the port for the DM-RS for the private stream (or multiple private streams). Such a scheme may, for example, facilitate efficient signaling in terms of overhead and flexibility, while determining that the DM-RS port for the public stream may be the same for different UEs, and / or the DM-RS port for the private stream may be different for different UEs.

[0105] In addition, in one or more of the above aspects, in process 700, a first subset of the set of DM-RS ports can be associated with a first CDM group in a plurality of CDM groups, wherein a second subset of the set of DM-RS ports can be associated with a second CDM group in a plurality of CDM groups, and wherein the first CDM group is different from the second CDM group. Such a scheme can facilitate, for example, that the DM-RS ports (and / or DM-RS sequences) for a common stream can be the same for different UEs, while the DM-RS ports for the common stream can still be different from the CDM group of the DM-RS ports for a private stream (or multiple private streams).

[0106] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) an identifier of a DM-RS sequence for initializing a DM-RS for a common stream, an identifier of a DM-RS sequence for initializing a DM-RS for a private stream, or a combination thereof. In addition, in these aspects, the identifier of the DM-RS sequence for initializing a DM-RS for a common stream may be different from the identifier of the DM-RS sequence for initializing a DM-RS for a private stream. Such a scheme may facilitate, for example, that the DM-RS sequence for a common stream may be the same for different UEs, while the DM-RS sequence for a common stream may still be different from the DM-RS sequence for a DM-RS port for a private stream (or multiple private streams).

[0107] In one or more of the above aspects, process 700 may further include receiving one or more first identifiers and a second identifier. In these aspects, determining the DM-RS configuration may further include: determining an identifier of a DM-RS sequence for initializing a DM-RS for a private stream based on the one or more first identifiers; and determining an identifier of a DM-RS sequence for initializing a DM-RS for a public stream based on the second identifier. In some aspects, the one or more first identifiers and / or the second identifier may be received using higher layer signaling, such as by using radio resource control (RRC) signaling. In some aspects, the one or more first identifiers may include (or may be equal to) and / or as specified in existing standards such as 5G / NR In these aspects, the UE may use the identifier and / or Generate a DM-RS sequence for the DM-RS port associated with the private flow. In some aspects, the second identifier may include (or may be equal to) an additional identifier (e.g., a new identifier not defined in existing standards such as 5G / NR) and may be configured to the UE for the public flow. In some aspects, the second identifier may be used In these aspects, the UE may determine which DM-RS ports correspond to common streams (e.g., based on any of the aspects described herein, etc.), and may assign c init Set to , to generate a DM-RS sequence for the DM-RS ports associated with the public stream. Such a scheme can facilitate, for example, that the DM-RS sequence for the public stream can be the same for different UEs, while the DM-RS sequence for the public stream can still be different from the DM-RS sequence for the DM-RS ports of the private stream (or multiple private streams).

[0108] In addition, in one or more aspects of the above aspects, in process 700, determining the identifier of the DM-RS sequence for initializing the DM-RS for the common stream may also be based on the time slot number and one or more symbol numbers of the DM-RS for the common stream. In these aspects, the UE may c init Set to A function of and setting the slot number and one or more symbol numbers to generate a DM-RS sequence for the DM-RS ports associated with the common stream. Such a scheme can, for example, promote DM-RS diversity and / or reduce interference.

[0109] In one or more of the above aspects, process 700 may also include receiving one or more first identifiers. In these aspects, determining the DM-RS configuration may also include: determining an identifier for a DM-RS sequence for initializing a DM-RS for a private stream based on the one or more first identifiers; and determining that a second identifier has not yet been received at the UE, and in response to the latter: determining the second identifier based on a cell identifier of the network entity; and determining an identifier for initializing a DM-RS sequence for a public stream based on the second identifier. In these aspects, the one or more first identifiers may correspond to (or may be equal to) the one or more first identifiers described above, and may exhibit one or more of its attributes. The second identifier may correspond to (or may be equal to) the second identifier described above, and may exhibit one or more of its attributes. The cell identifier may include (or may be equal to) a physical cell identifier such as a physical cell ID for 5G / NR. In some aspects, the UE may determine that it has not yet received the second identifier (e.g., ). In this case, for example, if the cell identifier is different from one or more first identifiers (e.g., If any one of the identifiers (such as , etc.) is used, the UE can use the cell identifier as the identifier of the DM-RS sequence for initializing the DM-RS for the common stream. Such a scheme can, for example, promote DM-RS diversity and / or reduce interference.

[0110] In addition, in one or more of the above aspects, in process 700, determining that the second identifier has not been received at the UE may also include determining that the cell identifier of the BS is equal to any one of the one or more first identifiers, and in response thereto determining that the second identifier is also based on the offset value. In these aspects, the UE can use the cell identifier with the offset value added to initialize the DM-RS sequence for the common stream. In some aspects, the offset value can be a fixed value (e.g., a pre-configured value, a value specified in a standard, etc.). In some aspects, the offset value can take a value of 1. Such a scheme can, for example, facilitate different UEs to use the same DM-RS sequence for a common stream without a dedicated identifier for the common stream (e.g., ).

[0111] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports, the density of DM-RS for public streams in an orthogonal frequency division multiplexing (OFDM) resource grid, the density of DM-RS for private streams in an OFDM resource grid, or any combination thereof. In addition, in these aspects, the density of DM-RS for public streams in an OFDM resource grid may be a non-constant function of one or more DM-RS ports, or the density of DM-RS for private streams in an OFDM resource grid may be a non-constant function of one or more DM-RS ports, or a combination thereof. In some aspects, the density of DM-RS in an OFDM resource grid may refer to a density in frequency (e.g., the number of subcarriers in a symbol or resource block (RB) to which the DM-RS is mapped), a density in time (e.g., the number of symbols in a time slot or RB to which the DM-RS is mapped), or a combination thereof. In some aspects, the density of DM-RS in an OFDM resource grid as a non-constant function of a DM-RS port may refer to the DM-RS density being different for different DM-RS ports. Such a scheme may, for example, facilitate denser DM-RS density for ports associated with public flows and sparser DM-RS for ports associated with private flows.

[0112] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) the density of DM-RS for common streams in an orthogonal frequency division multiplexing (OFDM) resource grid, the density of DM-RS for private streams in an OFDM resource grid, or a combination thereof. In addition, in these aspects, the density of DM-RS for common streams in an OFDM resource grid in a time slot including a downlink transmission may be equal to a first number of symbols per time slot, and the density of DM-RS for private streams in an OFDM resource grid in a time slot including a downlink transmission may be equal to a second number of symbols per time slot. In these aspects, the first number may be higher than the second number. Those skilled in the art will recognize that these aspects may additionally include the following in combination Figure 8 Any aspect described in A. For example, in combination with Figure 8 As described in more detail in A, for front-loading DM-RS, the density in the OFDM grid can be the same for all DM-RS ports, such as in 5G / NR, etc. In addition, as combined Figure 8 As described in more detail in A, one or more additional DM-RS symbols may include only DM-RS ports associated with the common stream. In some aspects, such as in conjunction with Figure 8 As described in more detail, in those additional DM-RS symbols, the resource elements (REs) that would be mapped to the DM-RS ports of the private stream may be used instead for PDSCH data.

[0113] In one or more of the above aspects, process 700 may further include receiving configuration information. In addition, in these aspects, determining the DM-RS configuration may further include: determining one or more symbol numbers of the DM-RS for the public stream based on the configuration information; and determining one or more symbol numbers of the DM-RS for the private stream based on the configuration information. Those skilled in the art will recognize that these aspects may additionally include the following in combination Figure 8 Any aspect described in A. For example, in combination with Figure 8 As described in more detail, the configuration information may indicate the number and one or more positions of additional DM-RS symbols carrying DM-RS ports for both public and private streams and / or the number and one or more positions of additional DM-RS symbols carrying DM-RS ports only for public streams.

[0114] In one or more aspects of the above aspects, in process 700, determining the DM-RS configuration may also include: determining the DM-RS configuration for the public stream based on the duration of the physical downlink shared channel (PDSCH) indicated in the DCI, the end symbol number of the PDSCH indicated in the DCI, the modulation and coding scheme (MCS) for the public stream indicated in the DCI, the MCS for the private stream indicated in the DCI, the number of layers associated with the public stream indicated in the DCI, the number of layers associated with the private stream indicated in the DCI, the number of DM-RS ports associated with the public stream indicated in the DCI, or the number of DM-RS ports associated with the private stream indicated in the DCI, or any combination thereof. One or more symbol numbers of the DM-RS for the private stream; and determining one or more symbol numbers of the DM-RS for the private stream based on the duration of the physical downlink shared channel (PDSCH) indicated in the DCI, the end symbol number of the PDSCH indicated in the DCI, the modulation and coding scheme (MCS) for the public stream indicated in the DCI, the MCS for the private stream indicated in the DCI, the number of layers associated with the public stream indicated in the DCI, the number of layers associated with the private stream indicated in the DCI, the number of DM-RS ports associated with the public stream indicated in the DCI, or the number of DM-RS ports associated with the private stream indicated in the DCI, or any combination thereof. Those skilled in the art will recognize that these aspects may additionally include the following in combination Figure 8 Any of the aspects described in A. For example, the number and one or more positions of additional DM-RS symbols carrying DM-RS ports for both public and private streams and / or the number and one or more positions of additional DM-RS symbols carrying DM-RS ports only for public streams can be a function of PDSCH duration, PDSCH end symbol, MCS of public and / or private streams, number of layers and / or DM-RS ports associated with public and / or private streams, etc.

[0115] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) the density of DM-RS for common streams in an orthogonal frequency division multiplexing (OFDM) resource grid, the density of DM-RS for private streams in an OFDM resource grid, or a combination thereof. Additionally, in these aspects, the density of DM-RS for common streams in an OFDM resource grid may be equal to a first number of subcarriers in a frequency domain resource allocation indicated by a DCI, and the density of DM-RS for private streams in an OFDM resource grid may be equal to a second number of subcarriers in a frequency domain resource allocation indicated by a DCI. In these aspects, the first number may be higher than the second number. Those skilled in the art will recognize that these aspects may additionally include the following in combination Figure 8 Any of the aspects described in the diagram 850 of FIG. Figure 8 As shown in more detail in FIG. 850 , some DM-RS ports (e.g., for public streams) may be mapped to a greater number of resource elements (REs) in a given time portion such as a symbol, a time slot, etc., compared to other DM-RS ports (e.g., for private streams). In addition, for example, as described in conjunction with Figure 8 As described in more detail in diagram 850 of , such mapping may be applied to both front-loaded DM-RS symbols as well as additional DM-RS symbols.

[0116] In addition, in one or more of the above aspects, in process 700, the first number of subcarriers in the frequency domain resource allocation may correspond to all subcarriers in the frequency domain resource allocation indicated by the DCI. Those skilled in the art will recognize that these aspects may further include the following in combination Figure 8 Any of the aspects described in the diagram 850 of FIG. Figure 8 As described in more detail in FIG. 850 , in both the pre-loaded DM-RS symbol 855 and / or the additional DM-RS symbol 865 , all REs may be mapped to one or more DM-RS ports. Such a scheme may facilitate, for example, common flows (e.g., channels H1P c ) channel estimation.

[0117] In one or more of the above aspects, in process 700, the DM-RS configuration may include (or may be equal to) the density of the DM-RS for the common stream in the orthogonal frequency division multiplexing (OFDM) resource grid, the density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof. In addition, in these aspects, the density of the DM-RS for the common stream in the OFDM resource grid and the density of the DM-RS for the private stream in the OFDM resource grid are such that one or more symbols of the OFDM resource grid include one or more resource elements used only for a subset of the DM-RS ports corresponding to the DM-RS for the common stream or the DM-RS for the private stream. Those skilled in the art will recognize that these aspects may additionally include the following in combination Figure 8 Any of the aspects described in the diagram 850 of FIG. Figure 8As shown in more detail in FIG. 850 , different DM-RS ports may be mapped to different DM-RS symbols such that in one symbol, all resource elements (REs) may be mapped to one or more DM-RS ports, but in an adjacent symbol (e.g., the next symbol), only a portion of the REs may be mapped to another one or more DM-RS ports. In some aspects, both symbols may be part of a front-loaded DM-RS. In other aspects, alternatively or in addition, both symbols may be part of an additional DM-RS.

[0118] In one or more aspects of the present disclosure, as an alternative or supplement to the above aspects, for example, in process 700, the UE and / or the network entity may be configured to operate at least in part according to one or more technical specifications (TS) generated by the Third Generation Partnership Project (3GPP).

[0119] Figure 8 A diagram 800 illustrating different DM-RS densities for different DM-RS ports according to various aspects of the present disclosure is shown. In some aspects, DM-RS port 0 may be assigned to (or may correspond to) a public stream, while DM-RS port 2 may be assigned to (or may correspond to) a private stream. The public stream and the private stream may correspond to any one or more of the aspects described herein, etc.

[0120] In one example, the resource grid shown in diagram 810 may correspond to a PDSCH spanning 12 symbols. In some aspects, for the front-loaded DM-RS symbol 815 and the (conventional) additional DM-RS symbol 825, the density of resource elements (REs) carrying DM-RS may be the same for all DM-RS ports (e.g., DM-RS port 0 for a common stream and / or DM-RS port 2 for a private stream), and in some aspects, may be equal to the density specified in 5G / NR (e.g., according to configuration type 0 described above). In some aspects, one or more (again) additional DM-RS symbols 820 and 830 may include only DM-RS ports associated with a common stream (e.g., DM-RS port 0), but may not include DM-RS ports associated with a private stream (e.g., DM-RS port 2). In some aspects, REs that do not carry DM-RS in the additional DM-RS symbols 820 and 830 (e.g., REs that will be mapped to DM-RS ports for a private stream in a conventional additional DM-RS symbol) may be used for PDSCH. Those skilled in the art will appreciate that, in diagram 810, the density (in the time domain) of symbols carrying DM-RS for a common stream (e.g., DM-RS port 0) is higher than the density (in the time domain) of symbols carrying DM-RS for a private stream (e.g., DM-RS port 2), and therefore facilitates the advantages described herein, among others.

[0121] In some aspects, the number and position of the additional one or more DM-RS symbols carrying DM-RS ports for both common and private streams and / or the number and position of the additional one or more DM-RS symbols carrying only one or more DM-RS ports for common streams can be configured (e.g., indicated to the UE). In addition, in some aspects, such symbols can be a function of the PDSCH duration, the PDSCH end symbol, the modulation and coding scheme (MCS) of the common and / or private streams, the number of layers and / or DM-RS associated with the common and / or private streams, etc., or any combination thereof.

[0122] In another example, the resource grid shown in diagram 850 can be a PDSCH spanning 9 symbols. In some aspects, certain DM-RS ports (e.g., DM-RS ports for common streams such as DM-RS port 0) can be mapped to a greater number of REs than other DM-RS ports (e.g., DM-RS ports for private streams such as DM-RS port 2). Such mapping can be applied to front-loaded DM-RS symbols 855 (e.g., carrying DM-RS port 0 for common streams) and 860 (e.g., carrying DM-RS port 2 for private streams) and additional DM-RS symbol 865 (e.g., carrying DM-RS port 0 for private streams) and its adjacent symbols where no REs are used for DM-RS. In some aspects, in one DM-RS symbol (e.g., in the front-loading DM-RS symbol 855 and / or in the additional DM-RS symbol 865), all REs may be mapped to one or more DM-RS ports (e.g., mapped to DM-RS ports for common streams such as DM-RS port 0), but in an adjacent DM-RS symbol (e.g., in the next symbol, such as in the front-loading DM-RS symbol 860), only a lower number of REs (e.g., half of the REs) are mapped to another one or more DM-RS ports (e.g., mapped to DM-RS ports for private streams such as DM-RS port 2). In some aspects, both the one DM-RS symbol and the adjacent DM-RS symbol may be part of the front-loading DM-RS or part of the additional DM-RS.

[0123] Fig. 9is a diagram illustrating an example process 900 performed at a network entity in accordance with various aspects of the present disclosure. In some aspects, the network entity may include (or may be) a base station 110, a base station 405, etc. In some aspects, the process 900 may be implemented by a portion of a transmit processor 220 of the base station 110, a portion of a Tx MIMO processor 230 of the base station 110, or any suitable component of the base station 110, etc. In some aspects, the process 900 may be implemented by any suitable component of the base station 405, including the processing stage 420, the combiner 425, the processing stage 430, the processing block 435, and the antenna 415. In some aspects, the process 900 may include Fig. 9 The blocks depicted in the process 900 may include additional blocks, fewer blocks, different blocks, or blocks arranged in a different manner than those depicted in the process 900. Additionally or alternatively, two or more blocks in the blocks of the process 900 may be executed in parallel.

[0124] like Fig. 9 As shown, process 900 may include determining a demodulation reference signal (DM-RS) configuration for a downlink transmission (block 910). The downlink transmission may be based on a rate division multiple access scheme. The downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream. In some aspects, the rate division multiple access scheme may include (or may be) the above in combination with Figure 4A The rate split described herein may include its individual features. In some aspects, the common stream may include (or may be) a jointly coded stream destined for multiple UEs, such as the stream W described above. c. In some aspects, the public stream may include (or may be) a first PDSCH, a first group of layers of a PDSCH, and the like. The DM-RS for the public stream may include (or may be) a DM-RS associated with a first PDSCH or a first group of layers of a PDSCH. In some aspects, the private stream may include (or may be) a stream destined for only a single UE. In some aspects, the private stream may include (or may be) a second PDSCH, a second group of layers of a PDSCH, and the like. The DM-RS for the private stream may include (or may be) a DM-RS associated with a second PDSCH or a second group of layers of a PDSCH. In some aspects, the private stream of process 900 may include (or may be) a plurality of private streams destined for a plurality of corresponding UEs. The DM-RS for the private stream of process 900 may include (or may be) a plurality of DM-RSs, each DM-RS being used for a corresponding one of the plurality of private streams. The DM-RS configuration may include (or may be equal to) any one or more of the aspects described herein and / or similar aspects that may facilitate the transmission of a DM-RS for a public stream and / or a DM-RS for a private stream. The corresponding DM-RS configuration for the public stream and / or for the private stream may include (or may be) one or more DM-RS ports, a code division multiplexing (CDM) group associated with the DM-RS port, a DM-RS sequence, an identifier for initializing the DM-RS sequence, a density of DM-RS in an orthogonal frequency division multiplexing (OFDM) resource grid, etc., or any combination thereof. Determining the DM-RS configuration may refer to any one or more of the activities described herein and / or similar activities that result in determining the DM-RS configuration.

[0125] like Fig. 9 As further shown, in some aspects, process 900 may include generating downlink control information (DCI) indicating a downlink transmission based on the DM-RS configuration (block 920). In some aspects, the DCI may include (or may be) the above in combination with Figure 5A or Figure 5B In some aspects, the DCI may schedule a first PDSCH or a first group of layers of a PDSCH, a second PDSCH or a second group of layers of a PDSCH, etc. In some aspects, generating DCI based on a DM-RS configuration may refer to any one or more of the activities described herein and / or similar activities that result in obtaining a DCI so that a destination UE of the DCI can determine a DM-RS configuration based on the received DCI.

[0126] In addition, if Fig. 9 As shown, in some aspects, process 900 may include sending DCI to a user equipment (UE) (block 930). In some aspects, the DCI may be included in one or more PDCCHs as described herein, among other things.

[0127] In addition, if Fig. 9 As shown, in some aspects, process 900 may include generating a downlink transmission based on the DM-RS configuration (block 940). In some aspects, generating may refer to any one or more of the activities described herein regarding obtaining a DM-RS based on the DM-RS configuration, e.g., considering any one or more aspects of the DM-RS configuration as described herein. In addition, Fig. 9 As further shown, in some aspects, process 900 may include sending a downlink transmission to a UE (block 950).

[0128] In one or more aspects of the present disclosure, in process 900, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports for DM-RS of a public stream, one or more DM-RS ports for DM-RS of a private stream, or a combination thereof. In addition, in these aspects, one or more fields in the DCI may indicate one or more DM-RS ports for DM-RS of a public stream, one or more DM-RS ports for DM-RS of a private stream, or a combination thereof. In combination with the above Figure 7 The description regarding indicating one or more DM-RS ports through one or more fields in the DCI applies accordingly.

[0129] In one or more of the above aspects, in process 900, the DM-RS configuration may include (or may be equal to) the DM-RS configuration includes one or more DM-RS ports of DM-RS for a common stream, one or more DM-RS ports of DM-RS for a private stream, or a combination thereof. In addition, in these aspects, one or more fields in the DCI may indicate a set of DM-RS ports for downlink transmission, the number of layers for the common stream, and the number of layers for the private stream, so that the UE can determine the one or more DM-RS ports of DM-RS for the common stream as a first subset of the group of DM-RS ports whose number of elements is equal to the number of layers for the common stream, and determine the one or more DM-RS ports of DM-RS for the private stream as a second subset of the group of DM-RS ports whose number of elements is equal to the number of layers for the private stream. In combination with the above Figure 7 The description about indicating a set of DM-RS ports and the number of layers through one or more fields in the DCI applies accordingly.

[0130] In one or more of the above aspects, in process 900, the DM-RS configuration may include (or may be equal to) one or more DM-RS ports for DM-RS for a common stream, one or more DM-RS ports for DM-RS for a private stream, or a combination thereof. In addition, in these aspects, one or more fields in the DCI may indicate a group of DM-RS ports for downlink transmission, so that the UE can: determine multiple CDM groups based on the group of DM-RS ports, each CDM group corresponding to a single DM-RS port in the group of DM-RS ports; determine a first subset of the group of DM-RS ports as one or more DM-RS ports for DM-RS for a common stream based on the multiple CDM groups; and determine a second subset of the group of DM-RS ports as one or more DM-RS ports for DM-RS for a private stream based on the multiple CDM groups. In combination with the above Figure 7 The description about indicating a group of DM-RS ports through DCI to enable the UE to determine multiple CDM groups, etc. applies accordingly.

[0131] In one or more of the above aspects, in process 900, the DM-RS configuration may include (or may be equal to) an identifier of a DM-RS sequence for initializing a DM-RS for a public stream, an identifier of a DM-RS sequence for initializing a DM-RS for a private stream, or a combination thereof. In addition, in these aspects, the identifier of the DM-RS sequence for initializing a DM-RS for a public stream is different from the identifier of the DM-RS sequence for initializing a DM-RS for a private stream. Figure 7 The description about initializing the DM-RS sequence using different identifiers applies accordingly.

[0132] In addition, in one or more of the above aspects, process 900 may include sending one or more first identifiers and a second identifier to enable the UE to determine an identifier of a DM-RS sequence for initializing a DM-RS for a private stream based on the one or more first identifiers, and determine an identifier of a DM-RS sequence for initializing a DM-RS for a public stream based on the second identifier. Figure 7 The description regarding initializing a DM-RS sequence using one or more first identifiers and second identifiers applies accordingly.

[0133] In one or more of the above aspects, in process 900, the DM-RS configuration may include (or may be equal to) the DM-RS configuration may include the density of the DM-RS for public streams in an orthogonal frequency division multiplexing (OFDM) resource grid, the density of the DM-RS for private streams in an OFDM resource grid, or a combination thereof. In addition, in these aspects, the density of the DM-RS for public streams in the OFDM resource grid may be a non-constant function of one or more DM-RS ports, or the density of the DM-RS for private streams in the OFDM resource grid may be a non-constant function of one or more DM-RS ports, or a combination thereof. In combination with the above Figure 7 The description regarding the density of one or more DM-RS as a function of one or more DM-RS ports applies accordingly.

[0134] In one or more of the above aspects, in process 900, the DM-RS configuration may include (or may be equal to) the density of DM-RS for common streams in an orthogonal frequency division multiplexing (OFDM) resource grid, the density of DM-RS for private streams in an OFDM resource grid, or a combination thereof. Further, in these aspects, the density of DM-RS for common streams in an OFDM resource grid in a time slot including downlink transmission may be equal to a first number of symbols per time slot, and the density of DM-RS for private streams in an OFDM resource grid in a time slot including downlink transmission may be equal to a second number of symbols per time slot. Further, in these aspects, the first number may be higher than the second number. In combination with the above Figure 7 The description regarding the number of DM-RS symbols per slot applies accordingly.

[0135] In one or more of the above aspects, in process 900, the DM-RS configuration may include (or may be equal to) the density of DM-RS for common streams in an orthogonal frequency division multiplexing (OFDM) resource grid, the density of DM-RS for private streams in an OFDM resource grid, or a combination thereof. Additionally, in these aspects, the density of DM-RS for common streams in an OFDM resource grid may be equal to a first number of subcarriers in a frequency domain resource allocation indicated by the DCI, and the density of DM-RS for private streams in an OFDM resource grid may be equal to a second number of subcarriers in a frequency domain resource allocation indicated by the DCI. Additionally, in these aspects, the first number is higher than the second number. In combination with the above Figure 7 The description regarding the number of subcarriers used for DM-RS applies accordingly.

[0136] In one or more aspects of the present disclosure, as an alternative or supplement to the above aspects, for example, in process 700, the UE and / or the network entity may be configured to operate at least in part according to one or more technical specifications (TS) generated by the Third Generation Partnership Project (3GPP). In addition, those skilled in the art will recognize that in combination with Figure 7 Any of the aspects described for the UE may additionally or alternatively be used in conjunction with Fig. 9 Aspects described for network entities.

[0137] In the following, several aspects of the present disclosure are presented:

[0138] Aspect 1. A method of wireless communication, the method being performed at a user equipment (UE), the method comprising:

[0139] receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream;

[0140] The DM-RS for the common stream and the DM-RS for the private stream are determined based on the DCI.

[0141] RS configuration; and

[0142] The downlink transmission is received based on the DM-RS configuration.

[0143] Aspect 2. A method according to Aspect 1, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate the one or more DM-RS ports of the DM-RS for the public stream, the one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof.

[0144] Aspect 3. A method according to any one of aspects 1 to 2, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, a number of layers for the common stream, and a number of layers for the private stream, and wherein determining the DM-RS configuration further comprises:

[0145] determining the one or more DM-RS ports of the DM-RS for the common stream as a first subset of the set of DM-RS ports whose number of elements is equal to the number of the layers for the common stream; and

[0146] The one or more DM-RS ports of the DM-RS for the private stream are determined as a second subset of the set of DM-RS ports whose number of elements is equal to the number of the layers for the private stream.

[0147] Aspect 4. The method according to any one of aspects 1 to 3, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, wherein the first one or more fields in the DCI indicate the presence of the common stream in the downlink transmission and a set of DM-RS ports for the downlink transmission, and wherein determining the DM-RS configuration further comprises:

[0148] Based on the indicated presence of the common stream, determining a first subset of the set of DM-RS ports as the one or more DM-RS ports for the DM-RS of the common stream; and

[0149] Based on the indicated presence of the common stream, a second subset of the set of DM-RS ports is determined as the one or more DM-RS ports for the DM-RS for the private stream.

[0150] Aspect 5. A method according to any one of Aspects 1 to 4, wherein the second one or more fields in the DCI indicate the number of layers used for the downlink transmission, and the first subset is also determined based on the number of layers.

[0151] Aspect 6. The method according to any one of aspects 1 to 5, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, and wherein determining the DM-RS configuration further comprises:

[0152] Determine a plurality of CDM groups based on the set of DM-RS ports, each CDM group corresponding to a single DM-RS port in the set of DM-RS ports;

[0153] determining a first subset of the set of DM-RS ports as the one or more DM-RS ports for the DM-RS of the common stream based on the plurality of CDM groups; and

[0154] A second subset of the set of DM-RS ports is determined as the one or more DM-RS ports of the DM-RS for the private stream based on the plurality of CDM groups.

[0155] Aspect 7. A method according to any one of Aspects 1 to 6, wherein the first subset of the set of DM-RS ports is associated with a first CDM group among the multiple CDM groups, wherein the second subset of the set of DM-RS ports is associated with a second CDM group among the multiple CDM groups, and wherein the first CDM group is different from the second CDM group.

[0156] Aspect 8. A method according to any one of Aspects 1 to 7, wherein the DM-RS configuration includes an identifier of a DM-RS sequence for initializing the DM-RS for the public stream, an identifier of a DM-RS sequence for initializing the DM-RS for the private stream, or a combination thereof, wherein the identifier of the DM-RS sequence for initializing the DM-RS for the public stream is different from the identifier of the DM-RS sequence for initializing the DM-RS for the private stream.

[0157] Aspect 9. The method according to any one of aspects 1 to 8, further comprising:

[0158] receiving one or more first identifiers and second identifiers;

[0159] And wherein determining the DM-RS configuration further comprises:

[0160] determining the identifier of the DM-RS sequence for initializing the DM-RS for the private stream based on the one or more first identifiers; and

[0161] The identifier of the DM-RS sequence for initializing the DM-RS for the common stream is determined based on the second identifier.

[0162] Aspect 10. A method according to any one of Aspects 1 to 9, wherein determining the identifier of the DM-RS sequence used to initialize the DM-RS for the common stream is also based on the time slot number and one or more symbol numbers of the DM-RS for the common stream.

[0163] Aspect 11. The method according to any one of aspects 1 to 10, further comprising:

[0164] receiving one or more first identifiers;

[0165] And wherein determining the DM-RS configuration further comprises:

[0166] determining the identifier of the DM-RS sequence for initializing the DM-RS for the private stream based on the one or more first identifiers; and

[0167] determining that a second identifier has not been received at the UE, and in response thereto:

[0168] determining the second identifier based on a cell identifier of the network entity; and

[0169] The identifier of the DM-RS sequence for initializing the DM-RS for the common stream is determined based on the second identifier.

[0170] Aspect 12. The method according to any one of aspects 1 to 11, wherein determining that the second identifier has not been received at the UE further comprises:

[0171] determining that the cell identifier of the network entity is equal to any one of the one or more first identifiers, and in response thereto:

[0172] Determining the second identifier is also based on an offset value.

[0173] Aspect 13. A method according to any one of Aspects 1 to 12, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, a density of the DM-RS for the public stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or any combination thereof, and wherein the density of the DM-RS for the public stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or the density of the DM-RS for the private stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or a combination thereof.

[0174] Aspect 14. A method according to any one of Aspects 1 to 13, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, wherein the density of the DM-RS for the common stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a first number of symbols per time slot, and the density of the DM-RS for the private stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a second number of symbols per time slot, and wherein the first number is higher than the second number.

[0175] Aspect 15. The method according to any one of aspects 1 to 14, further comprising:

[0176] Receive configuration information;

[0177] And wherein determining the DM-RS configuration further comprises:

[0178] Determining one or more symbol numbers of the DM-RS for the common stream based on the configuration information; and

[0179] One or more symbol numbers of the DM-RS for the private stream are determined based on the configuration information.

[0180] Aspect 16. The method according to any one of aspects 1 to 15, wherein determining the DM-RS configuration further comprises:

[0181] determining one or more symbol numbers of the DM-RS for the common stream based on a duration of a physical downlink shared channel (PDSCH) indicated in the DCI, an end symbol number of the PDSCH indicated in the DCI, a modulation and coding scheme (MCS) for the common stream indicated in the DCI, an MCS for the private stream indicated in the DCI, a number of layers associated with the common stream indicated in the DCI, a number of layers associated with the private stream indicated in the DCI, a number of DM-RS ports associated with the common stream indicated in the DCI, or a number of DM-RS ports associated with the private stream indicated in the DCI, or any combination thereof; and

[0182] One or more symbol numbers of the DM-RS used for the private stream are determined based on the duration of a physical downlink shared channel (PDSCH) indicated in the DCI, the end symbol number of the PDSCH indicated in the DCI, the modulation and coding scheme (MCS) for the common stream indicated in the DCI, the MCS for the private stream indicated in the DCI, the number of layers associated with the common stream indicated in the DCI, the number of layers associated with the private stream indicated in the DCI, the number of DM-RS ports associated with the common stream indicated in the DCI, or the number of DM-RS ports associated with the private stream indicated in the DCI, or any combination thereof.

[0183] Aspect 17. A method according to any one of Aspects 1 to 16, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid is equal to a first number of subcarriers in a frequency domain resource allocation indicated by the DCI, and wherein the density of the DM-RS for the private stream in the OFDM resource grid is equal to a second number of subcarriers in the frequency domain resource allocation indicated by the DCI, and wherein the first number is higher than the second number.

[0184] Aspect 18. A method according to any one of Aspects 1 to 17, wherein the first number corresponds to all subcarriers in the frequency domain resource allocation indicated by the DCI.

[0185] Aspect 19. A method according to any one of Aspects 1 to 18, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid and the density of the DM-RS for the private stream in the OFDM resource grid make one or more symbols of the OFDM resource grid include one or more resource elements used only for a subset of DM-RS ports corresponding to the DM-RS for the common stream or the DM-RS for the private stream.

[0186] Aspect 20. A method of wireless communication, the method being performed at a network entity, the method comprising:

[0187] determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream;

[0188] generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration;

[0189] Sending the DCI to a user equipment (UE);

[0190] generating the downlink transmission based on the DM-RS configuration; and

[0191] The downlink transmission is sent to the UE.

[0192] Aspect 21. A method according to Aspect 20, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate the one or more DM-RS ports of the DM-RS for the public stream, the one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof.

[0193] Aspect 22. A method according to any one of Aspects 20 to 21, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, the number of layers for the public stream, and the number of layers for the private stream, so that the UE can determine the one or more DM-RS ports of the DM-RS for the public stream as a first subset of the set of DM-RS ports whose number of elements is equal to the number of layers for the public stream, and determine the one or more DM-RS ports of the DM-RS for the private stream as a second subset of the set of DM-RS ports whose number of elements is equal to the number of layers for the private stream.

[0194] Aspect 23. A method according to any one of Aspects 20 to 22, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, wherein one or more fields in the DCI indicate a group of DM-RS ports for the downlink transmission, so that the UE can: determine multiple CDM groups based on the group of DM-RS ports, each CDM group corresponding to a single DM-RS port in the group of DM-RS ports; determine a first subset of the group of DM-RS ports as the one or more DM-RS ports of the DM-RS for the public stream based on the multiple CDM groups; and determine a second subset of the group of DM-RS ports as the one or more DM-RS ports of the DM-RS for the private stream based on the multiple CDM groups.

[0195] Aspect 24. According to the method described in any one of Aspects 20 to 23, the DM-RS configuration includes an identifier of a DM-RS sequence for initializing the DM-RS for the public stream, an identifier of a DM-RS sequence for initializing the DM-RS for the private stream, or a combination thereof, wherein the identifier of the DM-RS sequence for initializing the DM-RS for the public stream is different from the identifier of the DM-RS sequence for initializing the DM-RS for the private stream.

[0196] Aspect 25. The method according to any one of aspects 20 to 24, further comprising:

[0197] One or more first identifiers and a second identifier are sent so that the UE can determine the identifier of the DM-RS sequence for initializing the DM-RS for the private stream based on the one or more first identifiers, and determine the identifier of the DM-RS sequence for initializing the DM-RS for the public stream based on the second identifier.

[0198] Aspect 26. A method according to any one of Aspects 20 to 25, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or the density of the DM-RS for the private stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or a combination thereof.

[0199] Aspect 27. A method according to aspects 20 to 26, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a first number of symbols per time slot, and wherein the density of the DM-RS for the private stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a second number of symbols per time slot, and wherein the first number is higher than the second number.

[0200] Aspect 28. A method according to any one of Aspects 20 to 27, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid is equal to a first number of subcarriers in a frequency domain resource allocation indicated by the DCI, and wherein the density of the DM-RS for the private stream in the OFDM resource grid is equal to a second number of subcarriers in the frequency domain resource allocation indicated by the DCI, and wherein the first number is higher than the second number.

[0201] Aspect 29. An apparatus for wireless communication, the apparatus comprising:

[0202] Memory; and

[0203] one or more processors coupled to the memory, the memory and the one or more processors being configured to:

[0204] receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream;

[0205] determining a DM-RS configuration of the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and

[0206] The downlink transmission is received based on the DM-RS configuration.

[0207] Aspect 30. An apparatus for wireless communication, the apparatus comprising:

[0208] Memory; and

[0209] one or more processors coupled to the memory, the memory and the one or more processors being configured to:

[0210] determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream;

[0211] generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration;

[0212] Sending the DCI to a user equipment (UE);

[0213] generating the downlink transmission based on the DM-RS configuration; and

[0214] The downlink transmission is sent to the UE.

[0215] Aspect 31. An apparatus for wireless communication (eg, the apparatus is configured for use at a user equipment (UE)), the apparatus comprising:

[0216] means for receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission comprises a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream;

[0217] means for determining a DM-RS configuration of the DM-RS for the common stream and the DM-RS for the private stream based on the DCI; and

[0218] Means for receiving the downlink transmission based on the DM-RS configuration.

[0219] Aspect 32. The apparatus for wireless communication according to aspect 31, further comprising means for performing the method according to any one of aspects 2 to 19.

[0220] Aspect 33. An apparatus for wireless communication (eg, the apparatus is configured for use at a network entity), the apparatus comprising:

[0221] means for determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission comprises a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream;

[0222] means for generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; means for sending the DCI to a user equipment (UE);

[0223] means for generating the downlink transmission based on the DM-RS configuration; and

[0224] Means for sending the downlink transmission to the UE.

[0225] Aspect 34. The apparatus for wireless communication according to aspect 33, the apparatus further comprising means for performing the method of any one of aspects 21 to 28.

[0226] Aspect 35. A non-transitory computer readable medium storing one or more instructions for wireless communication, the one or more instructions, when executed by one or more processors, causing the one or more processors to:

[0227] receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream;

[0228] The DM-RS for the common stream and the DM-RS for the private stream are determined based on the DCI.

[0229] RS configuration; and

[0230] The downlink transmission is received based on the DM-RS configuration.

[0231] Aspect 36. A non-transitory computer readable medium storing one or more instructions for wireless communication, the one or more instructions, when executed by one or more processors, causing the one or more processors to:

[0232] determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream;

[0233] generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration;

[0234] Sending the DCI to a user equipment (UE);

[0235] generating the downlink transmission based on the DM-RS configuration; and

[0236] The downlink transmission is sent to the UE.

[0237] Aspect 37. A computer program comprising instructions which, when executed by a computer, cause the computer to perform a method according to any one of aspects 1 to 19 or 20 to 28.

[0238] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the various aspects.

[0239] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software.

[0240] It is apparent that the systems and / or methods described herein can be implemented using various forms of hardware, firmware, 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 various aspects. Therefore, the operation and performance of these systems and / or methods are described herein without reference to specific software codes, and it should be understood that software and hardware used to implement these systems and / or methods can be designed based on the description herein.

[0241] Although the specific combination of features is set forth in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner that is not specifically set forth in the claims and / or is not disclosed in the specification. Although each dependent claim listed below may directly rely only on one claim, the disclosure of various aspects includes each dependent claim combined with each other claim in the claim set. The phrase "at least one" mentioned in the list of items refers to any combination of those items, including a single member. As an example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, and any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc, or any other ordering of a, b and c).

[0242] Any element, action or instruction used herein should not be interpreted as critical or essential unless explicitly described as such. In addition, as used herein, the articles "a" and "an" are intended to include one or more items and can be used interchangeably with "one or more". In addition, as used herein, the terms "set" and "group" are intended to include one or more items (e.g., related items, unrelated items, combinations of related items and unrelated items, etc.), and can be used interchangeably with "one or more". If only one item is intended to be referred to, the phrase "only one" or similar terms will be used. In addition, as used herein, the terms "having" and the like are intended to be open terms.

[0243] As used herein, the phrase "based on" should not be interpreted as referring to a closed set of information, one or more conditions, one or more factors, etc. In other words, the phrase "based on A" (where "A" can be information, a condition, a factor, etc.) should be interpreted as "based at least on A" unless specifically stated differently.

Claims

1. A method of wireless communication, the method being performed at a user equipment (UE), the method comprising: receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream; determining, based on the DCI, a DM-RS configuration of the DM-RS for the common stream and the DM-RS for the private stream; as well as The downlink transmission is received based on the DM-RS configuration.

2. The method according to claim 1, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate the one or more DM-RS ports of the DM-RS for the public stream, the one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof.

3. The method of claim 1 , wherein the DM-RS configuration comprises one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, a number of layers for the common stream, and a number of layers for the private stream, and wherein determining the DM-RS configuration further comprises: determining the one or more DM-RS ports of the DM-RS for the common stream as a first subset of the set of DM-RS ports whose number of elements is equal to the number of the layers for the common stream; as well as The one or more DM-RS ports of the DM-RS for the private stream are determined as a second subset of the set of DM-RS ports whose number of elements is equal to the number of the layers for the private stream.

4. The method of claim 1 , wherein the DM-RS configuration comprises one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, wherein a first one or more fields in the DCI indicates the presence of the common stream in the downlink transmission and a set of DM-RS ports for the downlink transmission, and wherein determining the DM-RS configuration further comprises: Based on the indicated presence of the common stream, determining a first subset of the set of DM-RS ports as the one or more DM-RS ports for the DM-RS of the common stream; as well as Based on the indicated presence of the common stream, a second subset of the set of DM-RS ports is determined as the one or more DM-RS ports for the DM-RS for the private stream. 5 . The method of claim 4 , wherein a second one or more fields in the DCI indicate a number of layers used for the downlink transmission, and the first subset is determined further based on the number of layers.

6. The method of claim 1 , wherein the DM-RS configuration comprises one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, and wherein determining the DM-RS configuration further comprises: Determine a plurality of CDM groups based on the set of DM-RS ports, each CDM group corresponding to a single DM-RS port in the set of DM-RS ports; determining, based on the plurality of CDM groups, a first subset of the set of DM-RS ports as the one or more DM-RS ports for the DM-RS of the common stream; as well as A second subset of the set of DM-RS ports is determined as the one or more DM-RS ports of the DM-RS for the private stream based on the plurality of CDM groups.

7. A method according to claim 6, wherein the first subset of the set of DM-RS ports is associated with a first CDM group among the multiple CDM groups, wherein the second subset of the set of DM-RS ports is associated with a second CDM group among the multiple CDM groups, and wherein the first CDM group is different from the second CDM group.

8. The method of claim 1 , wherein the DM-RS configuration comprises an identifier of a DM-RS sequence for initializing the DM-RS for the public stream, an identifier of a DM-RS sequence for initializing the DM-RS for the private stream, or a combination thereof, wherein the identifier of the DM-RS sequence for initializing the DM-RS for the public stream is different from the identifier of the DM-RS sequence for initializing the DM-RS for the private stream.

9. The method according to claim 8, further comprising: receiving one or more first identifiers and second identifiers; And wherein determining the DM-RS configuration further comprises: determining the identifier of the DM-RS sequence for initializing the DM-RS for the private stream based on the one or more first identifiers; as well as The identifier of the DM-RS sequence for initializing the DM-RS for the common stream is determined based on the second identifier.

10. The method of claim 9, wherein determining the identifier of the DM-RS sequence for initializing the DM-RS for the common stream is further based on a slot number and one or more symbol numbers of the DM-RS for the common stream.

11. The method according to claim 8, further comprising: receiving one or more first identifiers; And wherein determining the DM-RS configuration further comprises: determining the identifier of the DM-RS sequence for initializing the DM-RS for the private stream based on the one or more first identifiers; and determining that a second identifier has not been received at the UE, and in response thereto: determining the second identifier based on a cell identifier of the network entity; and The identifier of the DM-RS sequence for initializing the DM-RS for the common stream is determined based on the second identifier.

12. The method of claim 11, wherein determining that the second identifier has not been received at the UE further comprises: determining that the cell identifier of the network entity is equal to any one of the one or more first identifiers, and in response thereto: Determining the second identifier is also based on an offset value.

13. The method of claim 1 , wherein the DM-RS configuration comprises one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, a density of the DM-RS for the public stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or any combination thereof, and wherein the density of the DM-RS for the public stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or the density of the DM-RS for the private stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or a combination thereof.

14. The method of claim 1 , wherein the DM-RS configuration comprises a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, wherein the density of the DM-RS for the common stream in the OFDM resource grid in a time slot of the downlink transmission is equal to a first number of symbols per time slot, and the density of the DM-RS for the private stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a second number of symbols per time slot, and wherein the first number is higher than the second number.

15. The method according to claim 1, further comprising: Receive configuration information; And wherein determining the DM-RS configuration further comprises: Determine one or more symbol numbers of the DM-RS for the common stream based on the configuration information; as well as One or more symbol numbers of the DM-RS for the private stream are determined based on the configuration information.

16. The method of claim 1, wherein determining the DM-RS configuration further comprises: determining one or more symbol numbers of the DM-RS for the common stream based on a duration of a physical downlink shared channel (PDSCH) indicated in the DCI, an end symbol number of the PDSCH indicated in the DCI, a modulation and coding scheme (MCS) for the common stream indicated in the DCI, an MCS for the private stream indicated in the DCI, a number of layers associated with the common stream indicated in the DCI, a number of layers associated with the private stream indicated in the DCI, a number of DM-RS ports associated with the common stream indicated in the DCI, or a number of DM-RS ports associated with the private stream indicated in the DCI, or any combination thereof; and One or more symbol numbers of the DM-RS used for the private stream are determined based on the duration of a physical downlink shared channel (PDSCH) indicated in the DCI, the end symbol number of the PDSCH indicated in the DCI, the modulation and coding scheme (MCS) for the common stream indicated in the DCI, the MCS for the private stream indicated in the DCI, the number of layers associated with the common stream indicated in the DCI, the number of layers associated with the private stream indicated in the DCI, the number of DM-RS ports associated with the common stream indicated in the DCI, or the number of DM-RS ports associated with the private stream indicated in the DCI, or any combination thereof.

17. A method according to claim 1, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid is equal to a first number of subcarriers in a frequency domain resource allocation indicated by the DCI, and wherein the density of the DM-RS for the private stream in the OFDM resource grid is equal to a second number of subcarriers in the frequency domain resource allocation indicated by the DCI, and wherein the first number is higher than the second number.

18. The method of claim 17, wherein the first number corresponds to all subcarriers in the frequency-domain resource allocation indicated by the DCI.

19. The method of claim 1 , wherein the DM-RS configuration comprises a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid and the density of the DM-RS for the private stream in the OFDM resource grid are such that one or more symbols of the OFDM resource grid include one or more resource elements used only for a subset of DM-RS ports corresponding to the DM-RS for the common stream or the DM-RS for the private stream.

20. A method for wireless communication, the method being performed at a network entity, the method comprising: determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; Sending the DCI to a user equipment (UE); generating the downlink transmission based on the DM-RS configuration; as well as The downlink transmission is sent to the UE.

21. The method of claim 20, wherein the DM-RS configuration comprises one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate the one or more DM-RS ports of the DM-RS for the public stream, the one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof.

22. A method according to claim 20, wherein the DM-RS configuration includes one or more DM-RS ports of the DM-RS for the public stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, and wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, the number of layers for the public stream, and the number of layers for the private stream, so that the UE can determine the one or more DM-RS ports of the DM-RS for the public stream as a first subset of the set of DM-RS ports whose number of elements is equal to the number of layers for the public stream, and determine the one or more DM-RS ports of the DM-RS for the private stream as a second subset of the set of DM-RS ports whose number of elements is equal to the number of layers for the private stream.

23. The method of claim 20, wherein the DM-RS configuration comprises one or more DM-RS ports of the DM-RS for the common stream, one or more DM-RS ports of the DM-RS for the private stream, or a combination thereof, wherein one or more fields in the DCI indicate a set of DM-RS ports for the downlink transmission, so as to enable the UE to: determine a plurality of CDM groups based on the set of DM-RS ports, each CDM group corresponding to a single DM-RS port in the set of DM-RS ports; determining, based on the plurality of CDM groups, a first subset of the set of DM-RS ports as the one or more DM-RS ports for the DM-RS of the common stream; and determining a second subset of the set of DM-RS ports as the one or more DM-RS ports of the DM-RS for the private flow based on the plurality of CDM groups.

24. The method of claim 20, wherein the DM-RS configuration comprises an identifier of a DM-RS sequence for initializing the DM-RS for the public stream, an identifier of a DM-RS sequence for initializing the DM-RS for the private stream, or a combination thereof, wherein the identifier of the DM-RS sequence for initializing the DM-RS for the public stream is different from the identifier of the DM-RS sequence for initializing the DM-RS for the private stream.

25. The method according to claim 24, further comprising: One or more first identifiers and a second identifier are sent so that the UE can determine the identifier of the DM-RS sequence for initializing the DM-RS for the private stream based on the one or more first identifiers, and determine the identifier of the DM-RS sequence for initializing the DM-RS for the public stream based on the second identifier.

26. The method of claim 20, wherein the DM-RS configuration comprises a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or the density of the DM-RS for the private stream in the OFDM resource grid is a non-constant function of the one or more DM-RS ports, or a combination thereof.

27. A method according to claim 20, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a first number of symbols per time slot, and wherein the density of the DM-RS for the private stream in the OFDM resource grid in the time slot of the downlink transmission is equal to a second number of symbols per time slot, and wherein the first number is higher than the second number.

28. A method according to claim 20, wherein the DM-RS configuration includes a density of the DM-RS for the common stream in an orthogonal frequency division multiplexing (OFDM) resource grid, a density of the DM-RS for the private stream in the OFDM resource grid, or a combination thereof, and wherein the density of the DM-RS for the common stream in the OFDM resource grid is equal to a first number of subcarriers in a frequency domain resource allocation indicated by the DCI, and wherein the density of the DM-RS for the private stream in the OFDM resource grid is equal to a second number of subcarriers in the frequency domain resource allocation indicated by the DCI, and wherein the first number is higher than the second number.

29. An apparatus for wireless communication, the apparatus comprising: Memory; and one or more processors coupled to the memory, the memory and the one or more processors being configured to: receiving downlink control information (DCI) for a downlink transmission from a network entity, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a demodulation reference signal (DM-RS) for the common stream, a private stream, and the DM-RS for the private stream; determining, based on the DCI, a DM-RS configuration of the DM-RS for the common stream and the DM-RS for the private stream; as well as The downlink transmission is received based on the DM-RS configuration.

30. An apparatus for wireless communication, the apparatus comprising: Memory; and one or more processors coupled to the memory, the memory and the one or more processors being configured to: determining a demodulation reference signal (DM-RS) configuration for a downlink transmission, wherein the downlink transmission is based on a rate division multiple access scheme, and wherein the downlink transmission includes a common stream, a DM-RS for the common stream, a private stream, and a DM-RS for the private stream; generating downlink control information (DCI) indicating the downlink transmission based on the DM-RS configuration; Sending the DCI to a user equipment (UE); generating the downlink transmission based on the DM-RS configuration; as well as The downlink transmission is sent to the UE.

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