METHOD AND APPARATUS FOR RESOURCE MAPPING FOR DMRS PORTS - Patent application

Abstract

A method and apparatus for resource mapping for DMRS ports is disclosed, the method includes receiving, by a receiver, a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports, determining, by a processor, DMRS resources including a first portion of DMRS resources for the first port group and a second portion of DMRS resources for the second port group, and receiving, by the receiver, the DMRS mapped to the first and second portions of DMRS resources.

Description

[Technical field]

[0001] The subject matter disclosed herein relates generally to wireless communications, and more particularly, but not exclusively, to methods and apparatus for resource mapping for DMRS ports. [Background technology]

[0002] The following abbreviations and acronyms are defined with this document, at least some of which will be referenced herein.

[0003] 3rd Generation Partnership Project (3GPP), 5th Generation (5G), New Radio (NR), 5G Node B (gNB), Long Term Evolution (LTE), LTE-Advanced (LTE-A), E-UTRAN Node B (eNB), Universal Mobile Telecommunications System (UMTS), Worldwide Interoperable Microwave Access (WiMAX), Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), Wireless Local Area Networking (WLAN), Orthogonal Frequency Division Multiplexing (OFDM), Single Carrier Frequency Division Multiple Access (SC-FDMA), Downlink (DL), Uplink (UL), User Equipment (UE), Network Equipment (NE), Radio Access Technology (RAT), Receiver or Receiver (RX), Transmitter or Transmitter (TX), Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), Code Division Multiplexing (CDM), Control Resource Set (CORESET), Cyclic Redundancy Check (CRC), Downlink Control Information (DCI), Demodulation Reference Signal (DMRS, or DM-RS), Frequency Division Multiple Access (FDMA), Index / Identifier (ID), Information Element (IE), Modulation Coding Scheme (MCS), Multiple Input Multiple Output (MIMO), Multi-User MIMO (MU-MIMO), Orthogonal Cover Code (OCC), Physical Resource Block (PRB), Resource Element (RE), Radio Network Temporary Identifier (RNTI), Time Division Multiplexing (TDM), Transmit Receiving Point (TRP), Cell Radio Network Temporary Identifier (C-RNTI), Configuration Scheduling RNTI (CS-RNTI), Frequency Range 1 (FR1), Frequency Range 2 (FR2), System Information RNTI (SI-RNTI), Technical Specification (TS).

[0004] In wireless communications, such as a Third Generation Partnership Project (3GPP) mobile network, a wireless mobile network may provide seamless wireless communication services to wireless communication terminals having mobility, i.e., user equipment (UE). A wireless mobile network may be formed of multiple base stations, which may implement wireless communications with the UE.

[0005] 5G New Radio (NR) is the latest in the series of 3GPP standards and supports very high data rates with lower latency compared to its predecessor LTE (4G) technology. 3GPP defines two Frequency Range (FR) types: frequencies in the sub-6GHz range (from 450 to 6000MHz) are called FR1 and frequencies in the millimeter wave range (from 24.25GHz to 52.6GHz) are called FR2. 5G NR supports both FR1 and FR2 frequency bands.

[0006] Enhancements in multi-TRP / panel transmission are being studied, including improved reliability and robustness with both ideal and non-ideal backhaul between these TRPs (Transmit Receiving Points). A TRP is a device for transmitting and receiving signals and is controlled by the gNB through the backhaul between the gNB and the TRP.

[0007] To meet the demands for NR deployment advancements in Release 18, it is important to identify and specify the necessary enhancements to both downlink and uplink MIMO to facilitate the use of large antenna arrays, not only for FR1 but also for FR2. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] TS28.211 [Non-Patent Document 2] TS38.214 [Non-Patent Document 3] TS38.211 [Non-Patent Document 4] TS38.212 Summary of the Invention [Problem to be solved by the invention]

[0009] A method and apparatus for resource mapping for DMRS ports is disclosed. [Means for solving the problem]

[0010] According to a first aspect, there is provided a method including: receiving, by a receiver, a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; determining, by a processor, DMRS resources including a first portion of DMRS resources for the first port group and a second portion of DMRS resources for the second port group; and receiving, by the receiver, a DMRS mapped to the first and second portions of DMRS resources.

[0011] According to a second aspect, there is provided a method including: transmitting, by a transmitter, a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; determining, by a processor, DMRS resources including a first portion of DMRS resources for the first port group and a second portion of DMRS resources for the second port group; and transmitting, by the transmitter, the DMRS mapped to the first and second portions of the DMRS resources.

[0012] According to a third aspect, an apparatus is provided that includes a receiver that receives a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports, and a processor that determines DMRS resources including a first portion of DMRS resources for the first port group and a second portion of DMRS resources for the second port group, wherein the receiver further receives a DMRS mapped to the first and second portions of the DMRS resources.

[0013] According to a fourth aspect, an apparatus is provided that includes a transmitter that transmits a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports, and a processor that determines DMRS resources including a first portion of DMRS resources for the first port group and a second portion of DMRS resources for the second port group, wherein the transmitter further transmits a DMRS mapped to the first and second portions of the DMRS resources.

[0014] A more particular description of the embodiments will be given by reference to specific embodiments that are illustrated in the accompanying drawings, which are not to be considered limiting in scope as they depict only some embodiments, and in which the embodiments will be described and explained with additional specificity and detail using the accompanying drawings. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram illustrating a wireless communication system according to some implementations of the present disclosure. [Diagram 2] FIG. 1 is a schematic block diagram illustrating components of a user equipment (UE) according to some implementations of the present disclosure. [Diagram 3] FIG. 1 is a schematic block diagram illustrating components of a network equipment (NE) according to some implementations of the present disclosure. [Figure 4A] 1 is a schematic diagram illustrating an example of resource mapping for an additional DMRS port based on a legacy DMRS pattern, in accordance with some implementations of the present disclosure. [Figure 4B] 1 is a schematic diagram illustrating an example of resource mapping for an additional DMRS port based on a legacy DMRS pattern, in accordance with some implementations of the present disclosure. [Figure 5A]1 is a schematic diagram illustrating an example of an OCC-based CDM scheme for Type-1 and Type-2 DMRS in accordance with some implementations of the present disclosure. [Figure 5B] 1 is a schematic diagram illustrating an example of an OCC-based CDM scheme for Type-1 and Type-2 DMRS in accordance with some implementations of the present disclosure. [Figure 6A] 1 is a schematic diagram illustrating an example of RE grouping for different antenna port groups in accordance with some implementations of the present disclosure. [Figure 6B] 1 is a schematic diagram illustrating an example of RE grouping for different antenna port groups in accordance with some implementations of the present disclosure. [Figure 7] 11 is a flowchart illustrating steps of resource mapping for a DMRS port for reception of a DMRS by a UE or a gNB, in accordance with some implementations of the present disclosure. [Figure 8] 11 is a flowchart illustrating steps of resource mapping for a DMRS port for transmission of a DMRS by a UE or a gNB, in accordance with some implementations of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, the embodiments may take the form of a hardware-only embodiment, a software-only embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects.

[0017] Furthermore, one or more embodiments may take the form of a program product embodied in one or more computer-readable storage devices that store machine-readable code, computer-readable code, and / or program code, hereinafter referred to as “code.” The storage devices may be tangible, non-transitory, and / or non-transmittable.

[0018] Throughout this specification, reference to "one embodiment," "an embodiment," "an example," "some embodiments," "some examples," or similar language means that the particular feature, structure, or characteristic described is included in at least one embodiment or example. Thus, throughout this specification, instances of the phrases "in one embodiment," "in an example," "in some embodiments," and similar language may refer to the same embodiment, but do not necessarily all refer to the same embodiment. It may or may not include all of the disclosed embodiments. A feature, structure, element, or characteristic described in connection with one or some embodiments is applicable to other embodiments, unless otherwise specified. The terms "including," "comprising," "having," and variations thereof mean "including, but not limited to," unless otherwise specified.

[0019] An enumerated listing of items does not imply that any or all of the items are mutually exclusive unless expressly stated otherwise. The terms "a," "an," and "the" also refer to "one or more," and similarly, items referred to in the plural also include a reference to one or more instances of that item unless expressly stated otherwise.

[0020] Throughout this disclosure, terms such as "first," "second," "third," etc. are all used solely as designations to refer to relevant devices, components, procedural steps, etc., without implying any spatial or chronological order, unless otherwise specified. For example, a "first device" and a "second device" may refer to two separately formed devices, or two parts or components of the same device. In some cases, for example, a "first device" and a "second device" may be the same and may be arbitrarily named. Similarly, a "first step" of a method or process may be performed or carried out after or simultaneously with a "second step."

[0021] The term "and / or" as used herein should be understood to refer to and include any possible combination of one or more of the associated listed items. For example, "A and / or B" may refer to any of the three combinations: the presence of A only, the presence of B only, and the coexistence of both A and B. The character " / " generally indicates an "or" relationship between the associated items. However, it may also include an "and" relationship between the associated items. For example, "A / B" means "A or B," but it may also include the coexistence of both A and B unless the context indicates otherwise.

[0022] Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, and the like, to provide a thorough understanding of the embodiments. However, one of ordinary skill in the art will recognize that the embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and the like. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments.

[0023] Aspects of various embodiments are described below with reference to schematic flowchart illustrations and / or schematic block diagrams of methods, apparatus, systems, and program products. It will be understood that each block of the schematic flowchart illustrations and / or schematic block diagrams, and combinations of blocks in the schematic flowchart illustrations and / or schematic block diagrams, may be implemented by code. This code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, whereby the instructions, executed by the processor of the computer or other programmable data processing apparatus, create means for implementing the functions or acts specified in the schematic flowchart illustrations and / or schematic block diagrams.

[0024] The code may be stored in a storage device that can instruct a computer, other programmable data processing apparatus, or other device to function in a particular manner, such that the instructions stored in the storage device create an article of manufacture that includes instructions that implement the functions or acts specified in the schematic flow chart illustrations and / or schematic block diagrams.

[0025] The schematic flow chart diagrams and / or schematic block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of different apparatus, systems, methods, and program products according to various embodiments. In this regard, each block in the schematic flow chart diagrams and / or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of code for implementing the specified logical function(s). However, those skilled in the art will recognize that the flow chart diagrams do not necessarily have to be practiced in the order shown, and can be practiced without one or more of the specific steps, or with other steps not shown.

[0026] It should also be noted that, in some alternative implementations, the functions noted in the identified blocks may occur out of the order noted in the figures: For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

[0027] 1 is a schematic diagram illustrating a wireless communication system. It illustrates an embodiment of a wireless communication system 100. In one embodiment, the wireless communication system 100 may include user equipment (UE) 102 and network equipment (NE) 104. Although a particular number of UEs 102 and NEs 104 are illustrated in FIG. 1, one skilled in the art will appreciate that any number of UEs 102 and NEs 104 may be included in the wireless communication system 100.

[0028] The UE 102 may be referred to as a remote device, a remote unit, a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a fixed terminal, a subscriber station, a user terminal, an apparatus, a device, a user device, or by other terms used in the art.

[0029] In one embodiment, the UE 102 may be an autonomous sensor device, an alarm device, an actuator device, a remote control device, etc. In some other embodiments, the UE 102 may include a computing device such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smartphone, a smart television (e.g., a television connected to the Internet), a set-top box, a game console, a security system (including a security camera), a vehicle-mounted computer, a network device (e.g., a router, a switch, a modem), etc. In some embodiments, the UE 102 includes a wearable device such as a smart watch, a fitness band, an optical head-mounted display, etc. The UE 102 may communicate directly with one or more of the NEs 104.

[0030] The NE 104 may also be referred to as a base station, an access point, an access terminal, a base, a Node B, an eNB, a gNB, a Home Node B, a relay node, an apparatus, a device, or any other terminology used in the art. Throughout this specification, references to a base station may refer to any of the above-mentioned types of network equipment 104, such as eNBs and gNBs.

[0031] The NEs 104 may be distributed throughout a geographic region. The NEs 104 are generally part of a radio access network that includes one or more controllers communicatively coupled to one or more corresponding NEs 104. The radio access network is generally communicatively coupled to one or more core networks, which may be coupled to other networks, such as the Internet and the public switched telephone network. These and other elements of the radio access and core networks are not shown, but are generally familiar to those skilled in the art.

[0032] In one implementation, the wireless communication system 100 complies with 3GPP 5G New Radio (NR). In some implementations, the wireless communication system 100 complies with 3GPP protocols, where the NE 104 transmits using an OFDM modulation scheme in the DL and the UE 102 transmits using an SC-FDMA scheme or an OFDM scheme in the uplink (UL). However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocol, for example, WiMAX. This disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

[0033] The NE 104 may serve several UEs 102 in a serving area, e.g., a cell (or cell sector) or more cells, via wireless communication links. The NE 104 transmits DL communication signals to serve the UEs 102 in the time, frequency, and / or spatial domains.

[0034] A communication link is provided between the NE 104 and the UEs 102a, 102b, 102c, and 102d, which may be, for example, an NR UL or DL ​​communication link. Some UEs 102 may communicate simultaneously over different radio access technologies (RATs), such as NR and LTE. Direct or indirect communication links between two or more NEs 104 may be provided.

[0035] The NE 104 may also include one or more transmit reception points (TRPs) 104a. In some embodiments, the network equipment may be a gNB 104 that controls several TRPs 104a. Furthermore, there is a backhaul between two TRPs 104a. In some other embodiments, the network equipment may be a TRP 104a controlled by a gNB.

[0036] A communication link is provided between each of the NEs 104, 104a and the UEs 102, 102a, which may be, for example, an NR UL / DL communication link. Some of the UEs 102, 102a may communicate simultaneously over different radio access technologies (RATs), such as NR and LTE.

[0037] In some embodiments, the UE 102a may be capable of simultaneously communicating with two or more TRPs 104a using non-ideal or ideal backhaul. A TRP may be a transmission point of a gNB. Multiple beams may be used by the UE and / or the TRP. The two or more TRPs may be of different gNBs or of the same gNB. That is, different TRPs may have the same cell ID or different cell IDs. The terms "TRP" and "transmit-receive identity" may be used interchangeably throughout this disclosure.

[0038] 2 is a schematic block diagram illustrating components of a user equipment (UE) according to one embodiment. The UE 200 may include a processor 202, a memory 204, an input device 206, a display 208, and a transceiver 210. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touch screen. In some embodiments, the UE 200 may not include any input device 206 and / or display 208. In various embodiments, the UE 200 may include one or more processors 202 or may not include the input device 206 and / or the display 208.

[0039] The processor 202, in one embodiment, may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, the processor 202 may be a microcontroller, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processing unit, a field programmable gate array (FPGA), or a similar programmable controller. In some embodiments, the processor 202 executes instructions stored in the memory 204 to perform the methods and routines described herein. The processor 202 is communicatively coupled to the memory 204 and the transceiver 210.

[0040] Memory 204, in one embodiment, is a computer-readable storage medium. In some embodiments, memory 204 includes a volatile computer storage medium. For example, memory 204 may include RAM, including dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), and / or static RAM (SRAM). In some embodiments, memory 204 includes a non-volatile computer storage medium. For example, memory 204 may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, memory 204 stores data regarding trigger conditions for transmitting measurement reports to network equipment. In some embodiments, memory 204 also stores program code and associated data.

[0041] The input device 206, in one embodiment, may include any known computer input device, including a touch panel, buttons, a keyboard, a stylus, a microphone, etc. In some embodiments, the input device 206 may be integrated with the display 208, for example, as a touch screen or similar touch-sensitive display.

[0042] Display 208, in one embodiment, may include any known electronically controllable display or display device. Display 208 may be designed to output visual, auditory, and / or tactile signals.

[0043] The transceiver 210, in one embodiment, is configured to wirelessly communicate with network equipment. In some embodiments, the transceiver 210 comprises a transmitter 212 and a receiver 214. The transmitter 212 is used to transmit UL communication signals to the network equipment, and the receiver 214 is used to receive DL communication signals from the network equipment.

[0044] The transmitter 212 and receiver 214 may be any suitable type of transmitter and receiver. Although only one transmitter 212 and one receiver 214 are shown, the transceiver 210 may have any suitable number of transmitters 212 and receivers 214. For example, in some embodiments, the UE 200 includes multiple transmitter 212 and receiver 214 pairs for communicating over multiple wireless networks and / or radio frequency bands, each of the transmitter 212 and receiver 214 pairs configured to communicate over a different wireless network and / or radio frequency band.

[0045] 3 is a schematic block diagram illustrating components of a network equipment (NE) 300 according to one embodiment. The NE 300 may include a processor 302, a memory 304, an input device 306, a display 308, and a transceiver 310. As can be appreciated, the processor 302, the memory 304, the input device 306, the display 308, and the transceiver 310 may be similar to the processor 202, the memory 204, the input device 206, the display 208, and the transceiver 210 of the UE 200, respectively.

[0046] In some embodiments, the processor 302 controls the transceiver 310 to transmit DL signals or data to the UE 200. The processor 302 also controls the transceiver 310 to receive UL signals or data from the UE 200. In another example, the processor 302 may control the transceiver 310 to transmit DL signals to the UE 200 that include various configuration data.

[0047] In some embodiments, the transceiver 310 comprises a transmitter 312 and a receiver 314. The transmitter 312 is used to transmit DL communication signals to the UE 200, and the receiver 314 is used to receive UL communication signals from the UE 200.

[0048] The transceiver 310 may communicate with multiple UEs 200 simultaneously. For example, the transmitter 312 may transmit DL communication signals to the UEs 200. As another example, the receiver 314 may simultaneously receive UL communication signals from the UEs 200. The transmitter 312 and receiver 314 may be any suitable type of transmitter and receiver. Although only one transmitter 312 and one receiver 314 are shown, the transceiver 310 may have any suitable number of transmitters 312 and receivers 314. For example, the NE 300 may serve multiple cells and / or cell sectors, in which case the transceiver 310 includes a transmitter 312 and a receiver 314 for each cell or cell sector.

[0049] Due to the increasing need for multiplexing capacity of downlink and uplink demodulation reference signals (DMRSs) from various use cases, it is necessary to increase the number of orthogonal ports for DMRS. Based on the current specification, only 8 orthogonal DMRS ports and 12 orthogonal DMRS ports are supported for Type-1 and Type-2 DMRS, respectively. According to the requirement to increase the DMRS ports, for example, up to 24 DMRS ports, a resource mapping scheme should be defined.

[0050] Two DMRS configuration types are introduced in Release 15, which are called DMRS Type 1 and DMRS Type 2. Both of them can support single-symbol and double-symbol configurations, where two antenna ports are orthogonal on the same resource element using a length-2 OCC sequence, and eight antenna ports are orthogonal using a length-2 OCC sequence for double-symbol DMRS in addition to using a frequency-domain length-2 OCC sequence and two CDM groups. Specific patterns are designed as shown in the following Tables 1 and 2 for Type 1 and Type 2 DMRS, respectively. In the time domain, the frontload DMRS is used in the DMRS pattern. And a set of additional DMRS symbols may be optionally introduced, which are distributed in the scheduled data channel duration. Detailed patterns are designed as shown in Tables 3 and 4 for single-symbol (i.e., maxLength=1) and double-symbol (i.e., maxLength=2) DMRS, respectively. The mapping relationship between the PDSCH DMRS time index and the antenna port is designed as shown in Table 5. Detailed information about resource mapping for DMRS is described in TS28.211 as follows:

[0051] The UE shall assume that the PDSCH DMRS is mapped to physical resources according to configuration type 1 or configuration type 2 given by the higher layer parameter dmrs-Type.

[0052] The UE adjusts the scale factor so that the sequence r(m) complies with the transmit power specified in [6, TS38.214].

[0053]

number

[0054] is scaled by

[0055]

number

[0056] According to the resource element (k, l) p,μ In the above equation, we assume that w f (k'), w t (l'), and Δ are given by Tables 1 and 2, and the following conditions are satisfied: The resource elements are located within a common resource block allocated for PDSCH transmission The reference point for k is If the corresponding PDCCH is associated with CORESET0 and a Type0-PDCCH common search space and is addressed to the SI-RNTI, it is subcarrier 0 of the lowest numbered resource block in CORESET0; Otherwise, it is subcarrier 0 in common resource block 0. The reference point for l and the position of the first DMRS symbol l0 depends on the mapping type. Regarding PDSCH mapping type A, l is defined relative to the start of the slot If the upper layer parameter dmrs-TypeA-Position is equal to "pos3", then l0=3, otherwise l0=2. Regarding PDSCH mapping type B, l is defined relative to the start of the scheduled PDSCH resource l0=0 The location of the DMRS symbol is

[0057]

number

[0058] and duration l d In the above formula, For PDSCH mapping type A, d is the duration between the first OFDM symbol of a slot and the last OFDM symbol of a scheduled PDSCH resource in the slot For PDSCH mapping type B, d is the duration of the scheduled PDSCH resource, According to Tables 3 and 4.

[0059] [Table 1]

[0060] [Table 2]

[0061] [Table 3]

[0062] [Table 4]

[0063] [Table 5]

[0064] One or two scrambling IDs can be used for the DMRS sequence. When two scrambling IDs are configured, dynamic signaling may be used to indicate which one is used for DMRS transmission. More information is specified in TS38.211 as follows: The UE determines that the sequence r(n) is

[0065]

number

[0066] where the pseudorandom sequence c(i) is defined in Section 5.2.1. The pseudorandom sequence generator is

[0067]

number

[0068] where l is the number of OFDM symbols in a slot, and

[0069]

number

[0070] is the number of slots in the frame, ·

[0071]

number

[0072] If present, they are given by the higher layer parameters scramblingID0 and scramblingID1, respectively, in the DMRS-DownlinkConfig IE, and the PDSCH is scheduled by the PDCCH using DCI format 1_1 or 1_2 with CRC scrambled by the C-RNTI, MCS-C-RNTI, or CS-RNTI. ·

[0073]

number

[0074] If present, it is given by the higher layer parameter scramblingID0 in the DMRS-DownlinkConfig IE, and the PDSCH is scheduled by the PDCCH using DCI format 1_0 with CRC scrambled by the C-RNTI, MCS-C-RNTI, or CS-RNTI; ·

[0075]

number

[0076] and if not, ·

[0077]

number

[0078] and

[0079]

number

[0080] teeth, If the upper layer parameter dmrsDownlink-r16 in the DMRS-DownlinkConfig IE is given,

[0081]

number

[0082] where λ is the CDM group as defined in Section 7.4.1.1.2. Otherwise,

[0083]

number

[0084] is given by quantity n SCID ∈{0,1} is given by the DMRS sequence initialization field, if present, in the DCI associated with the PDSCH transmission when DCI format 1_1 or 1_2 in [4, TS38.212] is used, otherwise n SCID =0.

[0085] In this example with maxLength=2, resource mapping on DMRS ports 0-7 (e.g., ports 1000-1007 in Tables 1 and 5) and ports 0-11 (e.g., ports 1000-1011 in Tables 2 and 5) is defined for Type-1 and Type-2 DMRS, respectively. In Release 18, more than eight DMRS ports for Type-1 DMRS or more than twelve DMRS ports for Type-2 DMRS will be introduced to support high-dimensional DMRS. The maximum orthogonal DMRS port count can be 16 DMRS ports for Type-1 DMRS or more than 24 DMRS ports for Type-2 DMRS.

[0086] In some other examples where maxLength=1, resource mapping on DMRS ports 0-3 (e.g., ports 1000-1003 in Tables 1 and 5) and ports 0-5 (e.g., ports 1000-1005 in Tables 2 and 5) for Type-1 and Type-2 DMRS are defined. In Release 18, more than four DMRS ports for Type-1 DMRS or more than six DMRS ports for Type-2 DMRS are planned to be introduced to support high-dimensional DMRS. The maximum orthogonal DMRS port count may be eight DMRS ports for Type-1 DMRS or more than twelve DMRS ports for Type-2 DMRS.

[0087] The DMRS patterns specified in Release 15 or Release 16 have been obtained through a simulation evaluation campaign to ensure good demodulation performance.

[0088] 4A and 4B are schematic diagrams illustrating example resource mapping for additional DMRS ports based on legacy DMRS patterns in accordance with some implementations of the present disclosure. The two diagrams show DMRS patterns for DMRS ports 0-7 (i.e., DMRS port group 0) and DMRS ports 0-11 (i.e., DMRS port group 0) for Type 1 and Type 2 DMRS, respectively. In FIG. 4A, Type 1 DMRS pattern 410 includes ports 0, 1, 4, 5 with time domain length 2 OCC and frequency domain length 2 OCC for CDM group 1, and ports 2, 3, 6, 7 with time domain length 2 OCC and frequency domain length 2 OCC for CDM group 2. In FIG. 4B , Type 2 DMRS pattern 420 includes ports 0, 1, 6, and 7 with time domain length 2 OCCs and frequency domain length 2 OCCs for CDM group 1, ports 2, 3, 8, and 9 with time domain length 2 OCCs and frequency domain length 2 OCCs for CDM group 2, and ports 4, 5, 10, and 11 with time domain length 2 OCCs and frequency domain length 2 OCCs for CDM group 3.

[0089] In order for a resource mapping scheme that can support up to 24 DMRS ports to reduce standard work, the resource mapping scheme for Type 1 DMRS ports 0-7 and Type 2 DMRS ports 0-11 should be reused as much as possible. The following description of time-frequency resources, OCC sequences, and scrambling sequences for additional DMRS ports 8-15 and DMRS ports 12-23 for Type 1 and Type 2 DMRS are given as an example where maxLength=2. The same method and / or principle can be applied to other examples where maxLength=1.

[0090] An additional DMRS resource is introduced to determine resources for additional DMRS ports, e.g., DMRS ports 8-15 (i.e., DMRS port group 1) for type 1 DMRS and DMRS ports 12-23 (i.e., DMRS port group 1) for type 2 DMRS. Thus, DMRS resources for multiple DMRS ports are assembled by available DMRS resources (i.e., DMRS resource 0) and additional DMRS resources (i.e., DMRS resource 1), where the additional DMRS resources are determined by the legacy DMRS design, but with some different parameters. A DMRS for one UE is mapped to only one DMRS resource. In this way, by utilizing the available Release 15 DMRS resource mapping scheme as much as possible, multiple DMRS ports introduced by multiple MU-MIMO users can be supported. To simplify the aggregation scheme and signaling indication for the DMRS port to be used, a similar configuration including dmrs-Type, maxLength is used for DMRS resource 0 and DMRS resource 1. Additional parameters for CDM group λ, subcarrier offset between CDM groups Δ, time-domain and frequency-domain OCC sequences w f (k'), w t (l') and the DMRS sequence may be the same or not, depending on the actual resource mapping scheme described in the following paragraph. For the additional DMRS resource 1, a different DM-RS sequence or DM-RS sequence group or OCC sequence group, RE group and OFDM symbol group may be used.

[0091] Sequence-based CDM method For the first type of scheme, one DM-RS sequence is used for one DMRS resource corresponding to a DMRS port group. The DM-RS sequence is generated based on one initial scrambling ID from a scrambling ID group. In particular, DM-RS sequence 0 is used for ports 0 to 7 for type-1 DMRS and ports 0 to 11 for type-2 DMRS, and DM-RS sequence 1 is used for ports 8 to 15 for type-1 DMRS and ports 12 to 23 for type-2 DMRS. The parameters of CDM group λ, the subcarrier offset between CDM groups Δ, the time domain and frequency domain OCC sequences w f (k'), w t (l') is the same for DMRS port i (0-7 for DMRS Type 1 and 0-11 for DMRS Type 2) and DMRS port i+k (k=8 for DMRS Type 1 and k=12 for DMRS Type 2 in the case of maxLength=2, and k=4 for DMRS Type 1 and k=6 for DMRS Type 1 in the case of maxLength=1). An example is shown in Table 6 for Type 1 DMRS. In this way, interference between different DMRS port groups can be mitigated by beamforming techniques. For the initial scrambling ID for the DM-RS sequence, the existing configured scrambling ID can be reused by the two higher layer parameters scramblingID0 and scramblingID1. One scrambling ID can be used for sequence generation for one DMRS resource. Alternatively, two additional scrambling IDs can be used because four TRPs are targeted in the Release 18 design. Two scrambling IDs (i.e., consisting of a scrambling ID group) can potentially be used for one DMRS resource. Two additional scrambling IDs can be configured or fixed in the specification, for example, defined as scramblingID0+1 and scramblingID1+1.

[0092] [Table 6]

[0093] OCC-based CDM method In the second type of scheme, one OCC sequence group is used for one DMRS resource corresponding to a DMRS port group. OCC sequence group 0 is used for ports 0 to 7 for type 1 DMRS and ports 0 to 11 for type 2 DMRS, and OCC sequence group 1 is used for ports 8 to 15 for type 1 DMRS and ports 12 to 23 for type 2 DMRS. The parameters of the CDM group λ, the subcarrier offset between the CDM groups Δ, the time domain OCC sequence w t(l') and the scrambling ID are the same for DMRS port i (0-7 for DMRS Type 1 and 0-11 for DMRS Type 2) and DMRS port i+k (k=8 for DMRS Type 1 and k=12 for DMRS Type 2 in the case of maxLength=2, and k=4 for DMRS Type 1 and k=6 for DMRS Type 1 in the case of maxLength=1). OCC sequence group 0 is determined by the legacy length-2 OCC sequence with repetition, and OCC sequence group 1 is determined by the newly introduced length-4 OCC sequence. For example, [1 1 1 1] and [1 -1 1 -1] are used as OCC sequences in OCC sequence group 0 for DMRS resource 0, and [1 1 -1 -1] and [1 -1 -1 1 1] are used as additional OCC sequences in OCC sequence group 1 for DMRS resource 1. An example is shown in Table 7 for Type 2 DMRS. For DMRS Type 2, there are 4 REs in one symbol of the PRB for the DMRS CDM group. An OCC sequence of length 4 can be easily used. However, for DMRS Type 1, there are 6 REs in one symbol of the PRB for the DMRS CDM group. This makes it difficult to use an OCC sequence of length 4. As a simple solution, two PRBs can be bundled into one to use an OCC sequence of length 4.

[0094] 5A and 5B are schematic diagrams illustrating examples of OCC-based CDM schemes for Type-1 and Type-2 DMRS in accordance with some implementations of the present disclosure.

[0095] 5A and 5B, as an example, three RE groups can be used for a length-4 OCC sequence for DMRS REs in two bundled PRBs. Four adjacent REs in one CDM group are used to configure the RE group for the length-4 OCC sequence to ensure channel estimation performance.

[0096] [Table 7]

[0097] FDM-based methods For the third type of scheme, one RE group is used for one DMRS resource corresponding to a DMRS port group. RE group 0 is used for ports 0 to 7 for type 1 DMRS and ports 0 to 11 for type 2 DMRS, and RE group 1 is used for ports 8 to 15 for type 1 DMRS and ports 12 to 23 for type 2 DMRS. The parameters of CDM group λ, the subcarrier offset between CDM groups Δ, the time domain and frequency domain OCC sequences w f (k'), w t (l') and the scrambling ID are the same for DMRS port i (0-7 for DMRS Type 1 and 0-11 for DMRS Type 2 in the case of maxLength=2, and k=4 for DMRS Type 1 and k=6 for DMRS Type 1 in the case of maxLength=1) and DMRS port i+k (k=8 for DMRS Type 1 and k=12 for DMRS Type 2). A similar Table 6 can be used for this scheme, and the DM-RS resources for different DM-RS port groups in the last column can be noted by the corresponding RE groups. However, different RE groups are used for DMRS resource 0 and DMRS resource 1. In the case of OCC sequences of length 2 used for each DMRS port group, because there are six REs in the group for type 1 DMRS, it is difficult to split them into two DMRS port groups. Therefore, two PRBs are bundled to do the resource mapping for the two DMRS port groups.

[0098] 6A and 6B are schematic diagrams illustrating examples of RE grouping for different antenna port groups according to some implementations of the present disclosure. As shown in FIG. 6A and 6B, RE group 0 and RE group 0 are used for DMRS port group 0 and DMRS port group 1, respectively.

[0099] For type-1 DMRS pattern 610, RE group 0 of CDM group 0 consists of REs from carriers {0 2 8 10} in PRB0 and carriers {4 6} in PRB1, and an OCC sequence of length 2 is used for carriers {0 2} in PRB0, carriers {8 10} in PRB0, and carriers {4 6} in PRB1, respectively, and RE group 1 of CDM group 0 consists of REs from carriers {4 6} in PRB0 and carriers {0 2 8 10} in PRB1, and an OCC sequence of length 2 is used for carriers {0 2} in PRB1, carriers {8 10} in PRB1, and carriers {4 6} in PRB2, respectively.

[0100] For type-2 DMRS pattern 620, RE group 0 of CDM group 0 consists of REs from carriers {0 6} in the PRB, and an OCC sequence of length 2 is used for carriers {0 6} in the PRB, and RE group 1 of CDM group 0 consists of REs from carriers {1 7} in the PRB, and an OCC sequence of length 2 is used for carriers {1 7} in the PRB. As another example, for type-2 DMRS pattern 620, RE group 0 of CDM group 0 consists of REs from carriers {0,1} in the PRB, and an OCC sequence of length 2 is used for carriers {0 1} in the PRB, and RE group 1 of CDM group 0 consists of REs from carriers {6,7} in the PRB, and an OCC sequence of length 2 is used for carriers {6,7} in the PRB. Here, the REs for one DMRS port group are uniformly distributed in the PRB, which is used to achieve better demodulation performance.

[0101] TDM-based methods For the fourth type of scheme, one OFDM symbol group is used for one DMRS resource corresponding to a DMRS port group. OFDM symbol group 0 is used for ports 0 to 7 for type 1 DMRS and ports 0 to 11 for type 2 DMRS, and OFDM symbol group 1 is used for ports 8 to 15 for type 1 DMRS and ports 12 to 23 for type 2 DMRS. The parameters of CDM group λ, the subcarrier offset between CDM groups Δ, the time domain and frequency domain OCC sequences w f (k'), w t (l') and the scrambling ID are the same for DMRS port i (0-7 for DMRS Type 1 and 0-11 for DMRS Type 2) and DMRS port i+k (for maxLength=2 case, k=8 for DMRS Type 1 and k=12 for DMRS Type 2, and for maxLength=1 case, k=4 for DMRS Type 1 and k=6 for DMRS Type 1). Alternatively, an OCC sequence of length 4 may be used for 4 OFDM symbols, with w t (l') can be changed to an OCC sequence of length 4. A similar Table 6 can be used for this scheme, except in the last column, different OFDM symbol groups are used for DMRS resource 0 and DMRS resource 1.

[0102] As an example shown in Table 8 for a DM-RS with a configuration of maxLength=2, two additional symbols {x, x+1} are introduced for DMRS resource 1. OFDM symbol group 0, i.e., symbols {0, 1}, and OFDM symbol group 1, i.e., {x, x+1}, are associated with DMRS port group 0 and DMRS port group 1, respectively. As a simple solution, x can be defined as 2. It is reasonable if an OCC sequence of length 4 in the time domain is introduced.

[0103] [Table 8]

[0104] As another alternative, x can be defined as the second OFDM symbol index for the double-symbol DMRS because the four available OFDM symbols in this double-symbol DMRS pattern can be reused. As an example, it can be one of the numerical values ​​in the "pos1" column shown in Table 4, which is determined according to the PDSCH duration and DMRS type. If these legacy values ​​are used, DMRS performance can be guaranteed because they are defined based on large-scale evaluation.

[0105] As another example for a DM-RS with a configuration of maxLength=1, one additional symbol {x} is introduced for DMRS resource 1. OFDM symbol group 0, i.e., symbol {0}, and OFDM symbol group 1, i.e., {x}, are associated with DMRS port group 0 and DMRS port group 1, respectively. As a simple solution, x may be defined as 1. It is reasonable if an OCC sequence of length 4 is introduced in the time domain.

[0106] As another alternative, x can be defined as the second OFDM symbol index for single-symbol DMRS because two available OFDM symbols in the single-symbol DMRS pattern can be reused. As an example, it can be one of the numerical values ​​in the "pos1" column shown in Table 3, which is determined according to the PDSCH duration and DMRS type. If these legacy values ​​are used, DMRS performance can be guaranteed because they are defined based on large-scale evaluation.

[0107] The proposed DM-RS resource mapping scheme may be applicable to both downlink and uplink DM-RS.

[0108] Because the number of OFDM symbols in one slot is limited, if the PDSCH may be jointly scheduled into two slots, the DMRS OFDM symbols from different groups may come from adjacent / different slots from the two slots.

[0109] It should be understood that the different schemes described may be dynamically or semi-statically switched due to different application scenarios, channel conditions, and scheduling requirements.

[0110] FIG. 7 is a flowchart illustrating steps of resource mapping for DMRS ports for reception of a DMRS by a UE 200 or a gNB 300 in accordance with some implementations of the present disclosure.

[0111] In step 702, the receiver 214 or 314 receives a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports.

[0112] In step 704, the processor 202 or 302 determines DMRS resources including a first portion of DMRS resources for the first port group and a second portion of DMRS resources for the second port group.

[0113] In step 706, the receiver 214 or 314 receives the DMRS mapped to the first and second portions of the DMRS resources.

[0114] FIG. 8 is a flowchart illustrating steps of resource mapping for a DMRS port for transmission of a DMRS by a UE 200 or a gNB 300 in accordance with some implementations of the present disclosure.

[0115] In step 802, the transmitter 212 or 312 transmits a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports.

[0116] In step 804, the processor 202 or 302 determines DMRS resources including a first portion of DMRS resources for a first port group and a second portion of DMRS resources for a second port group.

[0117] In step 806, the transmitter 212 or 312 transmits the DMRS mapped to the first and second portions of the DMRS resources.

[0118] In one aspect, some example clauses of the present disclosure relating to a method of receiving a DMRS by a UE or a gNB may be summarized as follows:

[0119] 1. receiving, by a receiver, a demodulation reference signal (DMRS) configuration having a plurality of DMRS ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; determining, by a processor, DMRS resources including a first portion of DMRS resources for a first port group and a second portion of DMRS resources for a second port group; receiving, by the receiver, a DMRS mapped to the first and second portions of the DMRS resources.

[0120] 2. The method of clause 1, wherein the multiple DMRS ports include more than four DMRSs or more than eight DMRS ports for a type 1 DMRS configured with maxLength=1 or maxLength=2, respectively, or more than six DMRSs or more than twelve DMRS ports for a type 2 DMRS configured with maxLength=1 or maxLength=2, respectively.

[0121] 3. The method of clause 1, wherein each DMRS port of the second set in the second port group is distinguished from a corresponding DMRS port of the first set in the first port group by a distinguishing parameter.

[0122] 4. The method of clause 3, wherein the distinguishing parameter is a scrambling ID group that indicates a different DMRS sequence.

[0123] 5. The method of clause 4, wherein each DMRS port of the second set in the second port group and a corresponding DMRS port of the first set in the first port group are assigned to the same code division multiplexing (CDM) group λ, subcarrier offset Δ between the CDM groups, and time domain orthogonal cover code (OCC) sequence w t (l'), and the frequency domain OCC sequence w f (k').

[0124] 6. The method of clause 4, wherein each scrambling ID in the second scrambling ID group for the second port group is associated with or configured separately from a corresponding scrambling ID in the first scrambling ID group for the first port group.

[0125] 7. The distinguishing parameter is the difference between different frequency domain OCC sequences w f The method of clause 3, wherein (k') is an OCC sequence group.

[0126] 8. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), and the method of clause 7, consisting of an identical scrambling ID.

[0127] 9. The method of clause 7, wherein the OCC sequence group for the second port group consists of OCC sequences of length 4 {[+1 +1 -1 -1], [+1 -1 -1 +1]}.

[0128] 10. The method of clause 7, wherein the OCC sequence group for the first port group consists of OCC sequences of length 4 {[+1 +1 +1 +1], [+1 -1 +1 -1]}.

[0129] 11. For a Type-1 DMRS, the method of clause 7, in which two physical resource blocks (PRBs) are bundled for application of an OCC sequence in an OCC sequence group.

[0130] 12. The method of clause 3, wherein the differentiating parameter is a resource element (RE) group indicating different groups of RE.

[0131] 13. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f (k') The method of clause 12.

[0132] 14. The method of clause 12, wherein for a Type-1 DMRS, the first RE group and the second RE group are pairwise selected from the CDM groups of the first PRB and the second PRB in the PRB bundle, respectively, in a non-overlapping frequency domain.

[0133] 15. The method of clause 12, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 2 8 10} in the first bundled PRB and carriers {4 6} in the second bundled PRB, and RE group 1 of CDM group 0 consists of REs from carriers {4 6} in the first bundled PRB and carriers {0 2 8 10} in the second bundled PRB.

[0134] 16. The method of clause 12, wherein for a Type-2 DMRS, the first RE group and the second RE group are pairwise selected from a CDM group of the PRB in a non-overlapping frequency domain manner.

[0135] 17. The method of clause 12, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 6} or {0,1} in the PRB, and RE group 1 of CDM group 0 consists of REs from carriers {1 7} or {6 7} in the PRB.

[0136] 18. The method of clause 3, wherein the distinguishing parameter is an orthogonal frequency division multiplexing (OFDM) symbol group indicating different groups of OFDM symbols.

[0137] 19. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f (k') The method of clause 18.

[0138] 20. The method of clause 18, wherein the OFDM symbols in the OFDM symbol group of the second port group are symbols {2,3} or symbols {x,x+1}, where x is derivable from an OFDM symbol index defined for a double-symbol DMRS.

[0139] 21. The method of clause 1, wherein parameters of the first and second parts of the DMRS resource, namely dmrs-Type and maxLength, are configured to be identical.

[0140] In another aspect, some example clauses of the present disclosure relating to a method of transmitting a DMRS by a UE or a gNB may be summarized as follows:

[0141] 22. Transmitting, by a transmitter, a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; determining, by a processor, DMRS resources including a first portion of DMRS resources for a first port group and a second portion of DMRS resources for a second port group; transmitting, by a transmitter, a DMRS mapped to the first and second portions of the DMRS resources.

[0142] 23. The method of clause 22, wherein the multiple DMRS ports include more than four DMRSs or more than eight DMRS ports for a type 1 DMRS configured with maxLength=1 or maxLength=2, respectively, or more than six DMRSs or more than twelve DMRS ports for a type 2 DMRS configured with maxLength=1 or maxLength=2, respectively.

[0143] 24. The method of clause 22, wherein each DMRS port of the second set in the second port group is distinguished from a corresponding DMRS port of the first set in the first port group by a distinguishing parameter.

[0144] 25. The method of clause 24, wherein the distinguishing parameter is a scrambling ID group that indicates a different DMRS sequence.

[0145] 26. The method of clause 25, wherein each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same code division multiplexing (CDM) group λ, subcarrier offset Δ between the CDM groups, and time domain orthogonal cover code (OCC) sequence w t (l'), and the frequency domain OCC sequence w f (k').

[0146] 27. The method of clause 25, wherein each scrambling ID in the second scrambling ID group for the second port group is associated with or configured separately from a corresponding scrambling ID in the first scrambling ID group for the first port group.

[0147] 28. The distinguishing parameter is the difference between the different frequency domain OCC sequences w f The method of claim 24, wherein (k') is an OCC sequence group.

[0148] 29. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), and the method of clause 28, consisting of an identical scrambling ID.

[0149] 30. The method of clause 28, wherein the OCC sequence group for the second port group consists of the OCC sequence of length 4 {[+1 +1 -1 -1], [+1 -1 -1 +1]}.

[0150] 31. The method of clause 28, wherein the OCC sequence group for the first port group consists of the OCC sequence of length 4 {[+1 +1 +1 +1], [+1 -1 +1 -1]}.

[0151] 32. For a Type-1 DMRS, the method of clause 28, in which two physical resource blocks (PRBs) are bundled for application of an OCC sequence in an OCC sequence group.

[0152] 33. The method of clause 24, wherein the differentiating parameter is a resource element (RE) group indicating different groups of RE.

[0153] 34. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f (k') The method of clause 33.

[0154] 35. The method of clause 33, wherein for a Type-1 DMRS, the first RE group and the second RE group are pairwise selected from the CDM groups of the first PRB and the second PRB in the PRB bundle, respectively, such that they do not overlap in frequency domain.

[0155] 36. The method of clause 33, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 2 8 10} in the first bundled PRB and carriers {4 6} in the second bundled PRB, and RE group 1 of CDM group 0 consists of REs from carriers {4 6} in the first bundled PRB and carriers {0 2 8 10} in the second bundled PRB.

[0156] 37. The method of clause 33, wherein for a Type-2 DMRS, the first RE group and the second RE group are pairwise selected from a CDM group of the PRB in a non-overlapping frequency domain manner.

[0157] 38. The method of clause 33, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 6} or {0,1} in the PRB, and RE group 1 of CDM group 0 consists of REs from carriers {1 7} or {6 7} in the PRB.

[0158] 39. The method of clause 24, wherein the distinguishing parameter is an orthogonal frequency division multiplexing (OFDM) symbol group indicating different groups of OFDM symbols.

[0159] 40. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f (k') The method of clause 39.

[0160] 41. The method of clause 39, wherein the OFDM symbols in the OFDM symbol group of the second port group are symbols {2,3} or symbols {x,x+1}, where x is derivable from an OFDM symbol index defined for a double-symbol DMRS.

[0161] 42. The method of clause 22, wherein parameters of the first and second parts of the DMRS resource, namely dmrs-Type and maxLength, are configured to be identical.

[0162] In a further aspect, some example clauses of the present disclosure regarding a UE or gNB for reception of a DMRS may be summarized as follows:

[0163] 43. A receiver for receiving a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; and a processor that determines DMRS resources including a first portion of DMRS resources for a first port group and a second portion of DMRS resources for a second port group, The receiver further receives a DMRS mapped to the first and second portions of the DMRS resources.

[0164] 44. The apparatus of clause 43, wherein the multiple DMRS ports include more than four DMRS or more than eight DMRS ports for a type 1 DMRS configured with maxLength=1 or maxLength=2, respectively, or more than six DMRS or more than twelve DMRS ports for a type 2 DMRS configured with maxLength=1 or maxLength=2, respectively.

[0165] 45. The apparatus of clause 43, wherein each DMRS port of the second set in the second port group is distinguished from a corresponding DMRS port of the first set in the first port group by a distinguishing parameter.

[0166] 46. ​​The apparatus of clause 45, wherein the distinguishing parameter is a scrambling ID group that indicates a different DMRS sequence.

[0167] 47. The apparatus of clause 46, wherein each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same code division multiplexing (CDM) group λ, subcarrier offset Δ between the CDM groups, and time domain orthogonal cover code (OCC) sequence w t (l'), and the frequency domain OCC sequence w f (k').

[0168] 48. The apparatus of clause 46, wherein each scrambling ID in the second scrambling ID group for the second port group is associated with or configured separately from a corresponding scrambling ID in the first scrambling ID group for the first port group.

[0169] 49. The distinguishing parameter is the difference between the different frequency domain OCC sequences w f (k') is an OCC sequence group, an apparatus of clause 45.

[0170] 50. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), and the device of clause 49 consisting of the same scrambling ID.

[0171] 51. The apparatus of clause 49, wherein the OCC sequence group for the second port group consists of an OCC sequence of length 4 {[+1 +1 -1 -1], [+1 -1 -1 +1]}.

[0172] 52. The apparatus of clause 49, wherein the OCC sequence group for the first port group consists of OCC sequences of length 4 {[+1 +1 +1 +1], [+1 -1 +1 -1]}.

[0173] 53. An apparatus of clause 49, in which for a Type-1 DMRS, two physical resource blocks (PRBs) are bundled for application of an OCC sequence in an OCC sequence group.

[0174] 54. The apparatus of clause 45, wherein the distinguishing parameter is a resource element (RE) group indicating different groups of RE.

[0175] 55. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f The device of clause 54, consisting of (k').

[0176] 56. The apparatus of clause 54, wherein for a Type-1 DMRS, the first RE group and the second RE group are pairwise selected from the CDM groups of the first PRB and the second PRB in the PRB bundle, respectively, such that they do not overlap in frequency domain.

[0177] 57. The apparatus of clause 54, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 2 8 10} in the first bundled PRB and carriers {4 6} in the second bundled PRB, and RE group 1 of CDM group 0 comprises REs from carriers {4 6} in the first bundled PRB and carriers {0 2 8 10} in the second bundled PRB.

[0178] 58. The apparatus of clause 54, wherein for a Type 2 DMRS, the first RE group and the second RE group are pairwise selected from a CDM group of the PRB in a non-overlapping frequency domain manner.

[0179] 59. The apparatus of clause 54, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 6} or {0,1} in the PRB, and RE group 1 of CDM group 0 comprises REs from carriers {1 7} or {6 7} in the PRB.

[0180] 60. The apparatus of clause 45, wherein the distinguishing parameter is an orthogonal frequency division multiplexing (OFDM) symbol group indicating different groups of OFDM symbols.

[0181] 61. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f The apparatus of clause 60, consisting of (k').

[0182] 62. The apparatus of clause 60, wherein the OFDM symbols in the OFDM symbol group of the second port group are symbols {2,3} or symbols {x,x+1}, where x is derivable from an OFDM symbol index defined for a double symbol DMRS.

[0183] 63. The apparatus of clause 43, wherein parameters of the first and second parts of the DMRS resource, namely dmrs-Type and maxLength, are configured to be identical.

[0184] In still further aspects, some example clauses of the present disclosure regarding a UE or gNB for transmission of a DMRS may be summarized as follows:

[0185] 64. A transmitter for transmitting a DMRS configuration having a plurality of demodulation reference signal (DMRS) ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; and a processor that determines DMRS resources including a first portion of DMRS resources for a first port group and a second portion of DMRS resources for a second port group, The transmitter further transmits the DMRS mapped to the first and second portions of the DMRS resources.

[0186] 65. The apparatus of clause 64, wherein the multiple DMRS ports include more than four DMRS or more than eight DMRS ports for a type 1 DMRS configured with maxLength=1 or maxLength=2, respectively, or more than six DMRS or more than twelve DMRS ports for a type 2 DMRS configured with maxLength=1 or maxLength=2, respectively.

[0187] 66. The apparatus of clause 64, wherein each DMRS port of the second set in the second port group is distinguished from a corresponding DMRS port of the first set in the first port group by a distinguishing parameter.

[0188] 67. The apparatus of clause 66, wherein the distinguishing parameter is a scrambling ID group that indicates a different DMRS sequence.

[0189] 68. The apparatus of clause 67, wherein each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same code division multiplexing (CDM) group λ, subcarrier offset Δ between the CDM groups, and time domain orthogonal cover code (OCC) sequence w t (l'), and the frequency domain OCC sequence w f (k').

[0190] 69. The apparatus of clause 67, wherein each scrambling ID in the second scrambling ID group for the second port group is associated with or configured separately from a corresponding scrambling ID in the first scrambling ID group for the first port group.

[0191] 70. The distinguishing parameter is the difference between the different frequency domain OCC sequences w f (k') is an OCC sequence group, an apparatus of Article 66.

[0192] 71. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), and the device of clause 70 consisting of the same scrambling ID.

[0193] 72. The apparatus of clause 70, wherein the OCC sequence group for the second port group consists of an OCC sequence of length 4 {[+1 +1 -1 -1], [+1 -1 -1 +1]}.

[0194] 73. The apparatus of clause 70, wherein the OCC sequence group for the first port group consists of OCC sequences of length 4 {[+1 +1 +1 +1], [+1 -1 +1 -1]}.

[0195] 74. The apparatus of clause 70, wherein for a Type-1 DMRS, two physical resource blocks (PRBs) are bundled for application of an OCC sequence in an OCC sequence group.

[0196] 75. The apparatus of clause 66, wherein the differentiating parameter is a resource element (RE) group indicating different groups of RE.

[0197] 76. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f The apparatus of Article 75, consisting of (k').

[0198] 77. The apparatus of clause 75, wherein for a Type-1 DMRS, the first RE group and the second RE group are pairwise selected from the CDM groups of the first PRB and the second PRB in the PRB bundle, respectively, such that they do not overlap in frequency domain.

[0199] 78. The apparatus of clause 75, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 2 8 10} in the first bundled PRB and carriers {4 6} in the second bundled PRB, and RE group 1 of CDM group 0 comprises REs from carriers {4 6} in the first bundled PRB and carriers {0 2 8 10} in the second bundled PRB.

[0200] 79. The apparatus of clause 75, wherein for a Type 2 DMRS, the first RE group and the second RE group are pairwise selected from a CDM group of the PRB in a non-overlapping frequency domain manner.

[0201] 80. The apparatus of clause 75, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 6} or {0,1} in the PRB, and RE group 1 of CDM group 0 comprises REs from carriers {1 7} or {6 7} in the PRB.

[0202] 81. The apparatus of clause 66, wherein the distinguishing parameter is an orthogonal frequency division multiplexing (OFDM) symbol group indicating different groups of OFDM symbols.

[0203] 82. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group are assigned to the same CDM group λ, subcarrier offset Δ between the CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f The device of Article 81, consisting of (k').

[0204] 83. The apparatus of clause 81, wherein the OFDM symbols in the OFDM symbol group of the second port group are symbols {2,3} or symbols {x,x+1}, where x is derivable from an OFDM symbol index defined for a double symbol DMRS.

[0205] 84. The apparatus of clause 64, wherein parameters of the first and second parts of the DMRS resource, namely dmrs-Type and maxLength, are configured to be identical.

[0206] Various embodiments and / or examples are disclosed to provide exemplary, explanatory information to enable those skilled in the art to practice the present disclosure. Features or components disclosed with respect to one embodiment or example are applicable to all embodiments or examples, unless expressly stated otherwise.

[0207] The embodiments may be embodied in other specific forms. The described embodiments are to be considered in all respects as merely illustrative and not restrictive. The scope is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. [Explanation of symbols]

[0208] 100 Wireless communication system 102 User Equipment (UE) 102a User Equipment (UE) 102b User Equipment (UE) 102c User Equipment (UE) 102d User Equipment (UE) 104 Network Equipment (NE), gNB 104a Transmission Reception Point (TRP), NE 200UE 202 Processor 204 Memory 206 Input Devices 208 Display 210 Transceiver 212 Transmitter 214 Receiver 300 Network Equipment (NE), gNB 302 Processor 304 Memory 306 Input Devices 308 Display 310 Transceiver 312 Transmitter 314 Receiver

Claims

1. receiving, by a receiver, a demodulation reference signal (DMRS) configuration having a plurality of DMRS ports, the plurality of DMRS ports including a first port group having a first set of DMRS ports and a second port group having a second set of DMRS ports; determining, by a processor, the DMRS resources including a first portion of DMRS resources for the first port group and a second portion of the DMRS resources for the second port group; receiving, by the receiver, a DMRS mapped to the first and second portions of the DMRS resources.

2. 2. The method of claim 1, wherein the plurality of DMRS ports includes more than four DMRS or more than eight DMRS ports for a Type 1 DMRS configured with maxLength=1 or maxLength=2, respectively, or more than six DMRS or more than twelve DMRS ports for a Type 2 DMRS configured with maxLength=1 or maxLength=2, respectively.

3. 2. The method of claim 1, wherein each DMRS port of the second set in the second port group is distinguished from a corresponding DMRS port of the first set in the first port group by a distinguishing parameter.

4. 4. The method of claim 3, wherein the distinguishing parameter is a scrambling ID group that indicates a different DMRS sequence, and each scrambling ID in the second scrambling ID group for the second port group is associated with or configured separately from a corresponding scrambling ID in the first scrambling ID group for the first port group.

5. The distinguishing parameters are different frequency domain OCC sequences w f The method of claim 3, wherein (k') is an OCC sequence group.

6. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group share the same CDM group λ, subcarrier offset Δ between CDM groups, and time domain OCC sequence w t (l') and the same scrambling ID.

7. 6. The method of claim 5, wherein the OCC sequence group for the second port group consists of length 4 OCC sequences {[+1 +1 -1 -1], [+1 -1 -1 +1]}.

8. The method of claim 5, wherein for a Type-1 DMRS, two physical resource blocks (PRBs) are bundled for application of an OCC sequence in the OCC sequence group.

9. The method of claim 3 , wherein the distinguishing parameter is a resource element (RE) group, which indicates different groups of REs.

10. Each DMRS port of the second set in the second port group and its corresponding DMRS port of the first set in the first port group share the same CDM group λ, subcarrier offset Δ between CDM groups, and time domain OCC sequence w t (l'), the scrambling ID, and the frequency domain OCC sequence w f The method of claim 9, comprising: (k').

11. 10. The method of claim 9, wherein for a Type-1 DMRS, the first RE group and the second RE group are selected in pairs from the CDM groups of the first and second PRBs in the PRB bundle, respectively, in a non-overlapping frequency domain, or for a Type-2 DMRS, the first RE group and the second RE group are selected in pairs from the CDM groups of the PRBs in a non-overlapping frequency domain.

12. 10. The method of claim 9, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 2 8 10} in a first bundled PRB and carriers {4 6} in a second bundled PRB, and RE group 1 of CDM group 0 consists of REs from carriers {4 6} in the first bundled PRB and carriers {0 2 8 10} in the second bundled PRB.

13. 10. The method of claim 9, wherein RE group 0 of CDM group 0 comprises REs from carriers {0 6} or {0,1} in the PRB, and RE group 1 of CDM group 0 consists of REs from carriers {1 7} or {6 7} in the PRB.

14. 4. The method of claim 3, wherein the distinguishing parameter is an Orthogonal Frequency Division Multiplexing (OFDM) symbol group indicating a different group of OFDM symbols, and the OFDM symbols in the OFDM symbol group of the second port group are symbols {2, 3} or symbols {x, x+1}, where x is derivable from an OFDM symbol index defined for a double-symbol DMRS.

15. The method of claim 1 , wherein parameters of the first and second parts of the DMRS resource, namely dmrs-Type and maxLength, are configured to be identical.

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