Determine the association between DMRS and PTRS

Abstract

Disclosed are an apparatus, a method, and a system for determining an association between DMRS and PTRS. An apparatus (200) includes a processor (202), the processor (202) determining (1402) the location and bandwidth of a scheduled physical resource block; and based on the location and bandwidth of the scheduled physical resource block, determining (1404) an associated demodulation reference signal port index within the physical resource block for the phase-tracking reference signal.

Description

Technical Field

[0001] The subject matter disclosed herein generally relates to wireless communication, and more particularly, to determining an association between a demodulation reference signal and a phase tracking reference signal. Background Art

[0002] The following abbreviations are defined herein, at least some of which are referenced in the following description: 3rd Generation Partnership Project (“3GPP”), Acknowledgment (“ACK”), Binary Phase Shift Keying (“BPSK”), Clear Channel Assessment (“CCA”), Cyclic Prefix (“CP”), Cyclic Redundancy Check (“CRC”), Channel State Information (“CSI”), Code Division Multiplexing (“CDM”), Common Search Space (“CSS”), Channel Quality Indicator (“CQI”), Codeword (“CW”), Discrete Fourier Transform (“DFT”), Discrete Fourier Transform Spread (“DFTS”), Downlink Control Information (“DCI”), Downlink (“DL”), Demodulation Reference Signal (“DMRS”), Downlink Pilot Time Slot (“DwPTS”), Enhanced Clear Channel Assessment (“eCCA”), Enhanced Mobile Broadband (“eMBB”), evolved Node B (“eNB”), European Telecommunications Standards Institute (“ETSI”), Frame-based Device (“FBE”), Frequency Division Duplexing (“FDD”), Frequency Division Multiple Access (“FDMA”), Frequency Division Multiplexing (“FDM”), Frequency Division Orthogonal Cover Code (“FD-OCC”), Guard Period (“GP”), Hybrid Automatic Repeat reQuest (“HARQ”), Internet of Things (“IoT”), Licensed-Assisted Access (“LAA”), Load-based Device (“LBE”), Listen Before Talk (“LBT”), Long Term Evolution (“LTE”), Multiple Access (“MA”), Modulation and Coding Scheme (“MCS”), Machine Type Communication (“MTC”), Multiple-Input Multiple-Output (“MIMO”), Multi-User Sharing Access (“MUSA”), Multi-User (“MU”), NarrowBand (“NB”), Negative ACKnowledgment (“NACK” or “NAK”), New Data Indicator (“NDI”), Next Generation Node B (“gNB”), Non-Orthogonal Multiple Access (“NOMA”), Orthogonal Frequency Division Multiplexing (“OFDM”), Primary Cell (“PCell”), Physical Broadcast Channel (“PBCH”), Physical Downlink Control Channel (“PDCCH”), Physical Downlink Shared Channel (“PDSCH”), Pattern Division Multiple Access (“PDMA”), Physical Hybrid ARQ Indicator Channel (“PHICH”), Precoding Matrix Indicator (“PMI”), Physical Random Access Channel (“PRACH”), Physical Resource Block (“PRB”), Phase Tracking Reference Signal (“PTRS”), Physical Uplink Control Channel (“PUCCH”), Physical Uplink Shared Channel (“PUSCH”), Quality of Service (“QoS”), Quadrature Phase Shift Keying (“QPSK”), Rank Indicator (“RI”), Radio Resource Control (“RRC”), Random Access Procedure (“RACH”), Resource Element (“RE”), Random Access Response (“RAR”), Radio Network Temporary Identifier (“RNTI”), Reference Signal (“RS”).Residual Minimum System Information (“RMSI”), Resource Spreading Multiple Access (“RSMA”), Round-Trip Time (“RTT”), Receive (“RX”), Sparse Code Multiple Access (“SCMA”), Scheduling Request (“SR”), Single-Carrier Frequency Division Multiple Access (“SC-FDMA”), Secondary Cell (“SCell”), Shared Channel (“SCH”), Signal-to-Interference plus Noise Ratio (“SINR”), System Information Block (“SIB”), Synchronization Signal (“SS”), Single-User (“SU”), Transport Block (“TB”), Transport Block Size (“TBS”), Time Division Duplex (“TDD”), Time Division Multiplexing (“TDM”), Time Division Orthogonal Cover Code (“TD-OCC”), Transmission Time Interval (“TTI”), Total Radiated Power (“TRP”), Transmit (“TX”), Uplink Control Information (“UCI”), User Entity / Equipment (Mobile Terminal) (“UE”), Uplink (“UL”), Universal Mobile Telecommunications System (“UMTS”), Uplink Pilot Time Slot (“UpPTS”), Ultra-Reliable and Low-Latency Communication (“URLLC”), and Worldwide Interoperability for Microwave Access (“WiMAX”). As used herein, “HARQ-ACK” may collectively represent an Acknowledgment (“ACK”) and a Negative Acknowledgment (“NACK”). An ACK means that the TB was correctly received, while a NACK (or NAK) means that the TB was incorrectly received.

[0003] In some wireless communication networks, PTRS and DMRS ports may be associated. In such networks, the manner in which the PTRS and DMRS ports are associated may be unknown. SUMMARY OF THE INVENTION

[0004] Disclosed are apparatuses for determining SINR. Methods and systems also perform the functions of the apparatuses. In one embodiment, the apparatus includes a receiver that receives information from a remote unit on an uplink channel. In some embodiments, the apparatus includes a processor that determines a signal-to-interference plus noise ratio for a scheduling layer of the remote unit based on the information received by the receiver from the remote unit on the uplink channel.

[0005] In one embodiment, the information from the remote unit on the uplink channel includes a report from the remote unit. In some embodiments, the report includes a channel quality indication report corresponding to two codewords. In various embodiments, in response to the channel quality indication for a second codeword of the two codewords indicating better channel quality than the channel quality indication for a first codeword of the two codewords, the processor exchanges the modulation and coding scheme, the transport block size, or a combination thereof for the first and second codewords in the downlink control information.

[0006] In some embodiments, in response to a channel quality indication of a second codeword among two codewords indicating better channel quality than a channel quality indication of a first codeword among the two codewords, a processor performs a precoder column permutation for layer 0 and a minimum layer of the second codeword. In one embodiment, a report includes a signal-to-interference-plus-noise ratio report or a channel quality indication report for each layer of multiple layers. In yet another embodiment, in response to a signal-to-interference-plus-noise ratio report of layer 0 not being an optimal signal-to-interference-plus-noise ratio report or a channel quality indication report of layer 0 not being an optimal channel quality indication report, the processor performs a precoder column permutation for layer 0 and the layer having an optimal signal-to-interference-plus-noise ratio report or an optimal channel quality indication report.

[0007] In certain embodiments, in response to a layer having an optimal signal-to-interference-plus-noise ratio report or an optimal channel quality indication report belonging to a second codeword, the processor exchanges a modulation and coding scheme, a transport block size, or a combination thereof of a first codeword and a second codeword in downlink control information. In various embodiments, the signal-to-interference-plus-noise ratio is based on measurements of an uplink channel. In one embodiment, in response to a signal-to-interference-plus-noise ratio of layer 0 not being the maximum signal-to-interference-plus-noise ratio based on measurements, the processor performs a precoder column permutation for layer 0 and the layer having the maximum signal-to-interference-plus-noise ratio. In some embodiments, in response to the maximum signal-to-interference-plus-noise ratio based on measurements belonging to a second codeword, the processor performs a precoder column permutation between the first codeword and the second codeword.

[0008] In various embodiments, in response to the maximum signal-to-interference-plus-noise ratio based on measurements belonging to a second codeword, the processor exchanges a modulation and coding scheme, a transport block size, or a combination thereof of a first codeword and a second codeword in downlink control information. In certain embodiments, in response to the maximum signal-to-interference-plus-noise ratio based on measurements belonging to a second codeword, the processor recalculates a modulation and coding scheme, a transport block size, or a combination thereof of the first codeword and indicates the modulation and coding scheme, the transport block size, or the combination thereof in downlink control information.

[0009] In one embodiment, a method for determining SINR includes receiving information from a remote unit on an uplink channel. In certain embodiments, the method includes determining a signal-to-interference-plus-noise ratio of a scheduling layer of the remote unit based on receiving information from the remote unit on the uplink channel.

[0010] In one embodiment, an apparatus for measuring SINR includes a processor that: determines a configuration of a downlink reference signal port; and measures a signal-to-interference-plus-noise ratio of each layer in multiple layers based on the configuration.

[0011] In one embodiment, the processor performs mapping of codewords to layers based on the number of layers in the multi - layer. In some embodiments, the apparatus includes a transmitter that transmits a report including the layer with the maximum signal - to - interference - plus - noise ratio based on measuring the signal - to - interference - plus - noise ratio of each layer.

[0012] In various embodiments, the processor determines a precoding matrix based on measuring the signal - to - interference - plus - noise ratio of each layer. In some embodiments, each column of the precoding matrix includes a precoding vector, and each precoding vector is determined based on the corresponding layer of the multi - layer. In one embodiment, in response to the maximum signal - to - interference - plus - noise ratio corresponding to a layer other than layer 0, the processor swaps the precoding vector for layer 0 with the precoding vector of the layer with the maximum signal - to - interference - plus - noise ratio in the precoding matrix to produce a permuted precoding matrix. In yet another embodiment, the processor determines a channel quality indication for each of a plurality of codewords based on the permuted precoding matrix. In some embodiments, the apparatus includes a transmitter that transmits a report including the channel quality indication for each codeword. In various embodiments, the base station unit determines a permuted precoding matrix based on the layer with the maximum signal - to - interference - plus - noise ratio and the precoding matrix. In one embodiment, the apparatus includes a transmitter that transmits a report including the precoding matrix.

[0013] In one embodiment, a method for measuring SINR includes determining the configuration of a downlink reference signal port. In various embodiments, the method includes measuring the signal - to - interference - plus - noise ratio of each layer of the multi - layer based on the configuration.

[0014] In one embodiment, an apparatus for determining the association between DMRS and PTRS includes a processor that determines the location and bandwidth of a scheduled physical resource block; and based on the location and bandwidth of the scheduled physical resource block, determines the associated demodulation reference signal port index within the physical resource block for the phase - tracking reference signal.

[0015] In one embodiment, the processor associates the phase - tracking reference signal with the demodulation reference signal port of the physical resource block carrying the phase - tracking reference signal having the minimum physical resource block index. In some embodiments, the processor associates the phase - tracking reference signal with the minimum demodulation reference signal port index of the physical resource block carrying the phase - tracking reference signal having the minimum physical resource block index.

[0016] In various embodiments, the processor associates a phase-tracking reference signal with a demodulation reference signal port index of a physical resource block carrying the phase-tracking reference signal having the smallest physical resource block index based on the scheduled physical resource block location in a carrier or bandwidth part. In some embodiments, the processor associates the phase-tracking reference signal with a demodulation reference signal port indicated in the downlink control information, radio resource control, or a combination thereof of the physical resource block carrying the phase-tracking reference signal having the smallest physical resource block index. In one embodiment, the processor determines a demodulation reference signal port index difference between adjacent physical resource blocks carrying the phase-tracking reference signal. In yet another embodiment, the determined demodulation reference signal port index difference is based on a demodulation reference signal port difference between two codewords. In certain embodiments, the determined demodulation reference signal port index difference is based on a default value. In various embodiments, the determined demodulation reference signal port index difference is based on signaling via downlink control information, radio resource control, or a combination thereof. In one embodiment, the signaling is part of an uplink grant or downlink assignment.

[0017] In some embodiments, the processor determines a phase-tracking reference signal resource element location within a physical resource block based on a demodulation reference signal port index. In certain embodiments, the processor determines that a phase-tracking reference signal precoding vector is the same as a precoding vector of an associated demodulation reference signal port. In various embodiments, the processor determines a phase-tracking reference signal resource element location within a physical resource block based on the smallest demodulation reference signal port index. In some embodiments, the processor determines a phase-tracking reference signal resource element location within a physical resource block based on radio resource control signaling.

[0018] In one embodiment, a method for determining an association between DMRS and PTRS includes determining a scheduled physical resource block location and bandwidth. In certain embodiments, the method includes determining a demodulation reference signal port index for an association within a physical resource block for a phase-tracking reference signal based on the location and bandwidth of the scheduled physical resource block. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] A more specific description of the embodiments briefly described above will be presented by reference to specific embodiments illustrated in the drawings. It is to be understood that these drawings depict only some embodiments and are not to be considered limiting of the scope, and the embodiments will be described and explained with additional features and details by using the drawings, wherein:

[0020] Figure 1 is a schematic block diagram illustrating one embodiment of a wireless communication system for determining an association between DMRS and PTRS;

[0021] Figure 2FIG. is a schematic block diagram of an embodiment of an apparatus that can be used to determine the association between DMRS and PTRS;

[0022] Figure 3 FIG. is a schematic block diagram of an embodiment of an apparatus that can be used to determine the association between DMRS and PTRS;

[0023] Figure 4 FIG. is a schematic block diagram of an embodiment of a DMRS pattern;

[0024] Figure 5 FIG. is a schematic block diagram of an embodiment of a PTRS pattern;

[0025] Figure 6 FIG. is a schematic flowchart of an embodiment of a method for exchanging MCS and / or TBS between two CWs;

[0026] Figure 7 FIG. is a schematic block diagram of an embodiment of MCS and TBS in two CWs before exchanging MCS and TBS;

[0027] Figure 8 FIG. is a schematic block diagram of an embodiment of MCS and TBS in two CWs after exchanging MCS and TBS;

[0028] Figure 9 FIG. is a schematic flowchart of an embodiment of a method for precoder permutation;

[0029] Figure 10 FIG. is a schematic block diagram of an embodiment of DMRS for multiple users;

[0030] Figure 11 FIG. is a schematic block diagram of an embodiment of PTRS for multiple users;

[0031] Figure 12 FIG. is a schematic flowchart of an embodiment of a method for determining SINR; and

[0032] Figure 13 FIG. is a schematic flowchart of an embodiment of a method for measuring SINR; and

[0033] Figure 14 FIG. is a schematic flowchart of an embodiment of a method for determining the association between DMRS and PTRS. DETAILED DESCRIPTION

[0034] As will be appreciated by one of ordinary skill 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 an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects that may generally be referred to herein as a “circuit,” “module,” or “system.” Additionally, the embodiments may take the form of a program product embodied in one or more computer-readable storage devices storing machine-readable code, computer-readable code, and / or program code referred to hereinafter as code. The storage device may be tangible, non-transitory, and / or non-transmissive. The storage device may not embody a signal. In certain embodiments, the storage device merely comprises a signal for accessing the code.

[0035] Certain functional units described in this specification may be labeled as modules for the purpose of more particularly emphasizing their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very large scale integration (“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, and the like.

[0036] A module may also be implemented in code and / or software to be executed by various types of processors. The identified code module may, for example, comprise one or more physical or logical blocks of executable code that may, for example, be organized as objects, procedures, or functions. However, the executable files of the identified module need not be physically located together, but may comprise disparate instructions stored in different locations that, when logically connected together, comprise the module and implement the stated purpose of the module.

[0037] In fact, a code module may be a single instruction or many instructions, and may even be distributed over several different code segments, different programs, and across several memory devices. Similarly, in this specification, operational data may be identified and illustrated within a module and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set or may be distributed over different locations, including on different computer-readable storage devices. Where a module or a portion of a module is implemented in software, the software portion is stored on one or more computer-readable storage devices.

[0038] Any combination of one or more computer-readable media can be utilized. The computer-readable media can be computer-readable storage media. The computer-readable storage media can be a storage device that stores code. The storage device can be, by way of example but not limitation, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micro-mechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0039] More specific examples (a non-exhaustive list) of storage devices will include the following: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (“RAM”), a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM” or flash memory), a portable compact disc read-only memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage media can be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0040] The code for performing the operations of the embodiments can be any number of lines and can be written in any combination of one or more programming languages including object-oriented programming languages such as Python, Ruby, Java, Smalltalk, C++, etc., and conventional procedural programming languages such as the “C” programming language, and / or machine languages such as assembly language. The code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter case, the remote computer can be connected to the user's computer through any type of network connection, including a local area network (“LAN”) or a wide area network (“WAN”), or can be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0041] References in this specification to “one embodiment,” “an embodiment,” or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, unless expressly stated otherwise, the phrases “in one embodiment,” “in an embodiment,” and similar language throughout the specification can, but do not necessarily, all refer to the same embodiment, but rather mean “one or more but not all embodiments.” Unless expressly stated otherwise, the terms “comprises,” “comprising,” “has,” and their variants mean “including but not limited to.” Unless expressly stated otherwise, a list of items does not imply 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.”

[0042] In addition, the features, structures, or characteristics of the described embodiments can 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, etc., to provide a thorough understanding of the embodiments. However, those skilled in the relevant art will recognize that the embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring some aspects of the embodiments.

[0043] Aspects of the embodiments are described below with reference to the schematic flowcharts and / or schematic block diagrams of methods, apparatuses, systems, and program products according to the embodiments. It will be understood that each block of the schematic flowcharts and / or schematic block diagrams, and combinations of blocks in the schematic flowcharts and / or schematic block diagrams, can be implemented by code. The code can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions executed via the processor of the computer or other programmable data processing apparatus create a means for implementing the functions / operations specified in the blocks of the schematic flowcharts and / or schematic block diagrams.

[0044] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other device to operate in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including the instructions that implement the functions / operations specified in the blocks of the schematic flowcharts and / or schematic block diagrams.

[0045] The code can also be loaded onto a computer, other programmable data processing apparatus, or other device, such that a series of operational steps are performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, such that the code executed on the computer or other programmable apparatus provides a process for implementing the functions / operations specified in the blocks of the flowchart and / or block diagram.

[0046] The schematic flowcharts and / or schematic block diagrams in the figures illustrate the possible architectures, functions, and operations of apparatuses, systems, methods, and program products according to various embodiments. In this regard, each block in the schematic flowcharts and / or schematic block diagrams can represent a module, segment, or portion of code that includes one or more executable instructions for implementing the specified logical function.

[0047] It should also be noted that, in some alternative embodiments, the functions of the annotations in the blocks may not occur in the order of the annotations in the figures. For example, two consecutive blocks shown may actually be executed substantially simultaneously, or these blocks may sometimes be executed in the reverse order, depending on the functions involved. Other steps and methods can be envisioned that are equivalent in function, logic, or effect to one or more blocks or portions of the illustrated figures.

[0048] Although various arrow types and line types may be employed in the flowcharts and / or block diagrams, it should be understood that they do not limit the scope of the corresponding embodiments. In fact, some arrows or other connectors may be used only to indicate the logical flow of the depicted embodiments. For example, an arrow may indicate a waiting or monitoring period of unspecified duration between the enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented by a system based on dedicated hardware that performs a particular function or operation, or a combination of dedicated hardware and code.

[0049] The description of the elements in each figure may refer to the elements of the preceding figures. In all the figures, like numbers refer to like elements, including alternative embodiments of like elements.

[0050] Figure 1 An embodiment of a wireless communication system 100 for determining an association between DMRS and PTRS is depicted. In one embodiment, the wireless communication system 100 includes a remote unit 102 and a base station unit 104. Even Figure 1 although a specific number of remote units 102 and base station units 104 are depicted, those skilled in the art will recognize that any number of remote units 102 and base station units 104 may be included in the wireless communication system 100.

[0051] In one embodiment, the remote unit 102 may include a computing device such as a desktop computer, laptop computer, personal digital assistant (“PDA”), tablet computer, smart phone, smart TV (e.g., a TV connected to the Internet), set-top box, game console, security system (including security cameras), in-vehicle computer, network device (e.g., router, switch, modem), airborne vehicle, drone, etc. In some embodiments, the remote unit 102 includes a wearable device such as a smart watch, fitness band, optical head-mounted display, etc. Additionally, the remote unit 102 may be referred to as a user unit, mobile device, mobile station, user, terminal, mobile terminal, fixed terminal, user station, UE, user terminal, device, or other terms used in the art. The remote unit 102 may communicate directly with one or more base station units 104 via UL communication signals.

[0052] The base station unit 104 can be distributed over a geographical area. In some embodiments, the base station unit 104 may also be referred to as an access point, access terminal, base station, base station, Node - B, eNB, gNB, home Node - B, relay node, device, core network, air server, or any other term used in the art. The base station unit 104 is generally part of a radio access network that includes one or more controllers communicatively coupled to one or more corresponding base station units 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, among other networks. These and other elements of the radio access and core networks are not shown, but are generally well known to those of ordinary skill in the art.

[0053] In one embodiment, the wireless communication system 100 complies with the 3GPP protocol, where the base station unit 104 transmits on the DL using an OFDM modulation scheme, and the remote unit 102 transmits on the UL using an SC - FDMA scheme or an OFDM scheme. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocols, such as WiMAX, among other protocols. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

[0054] The base station unit 104 can serve multiple remote units 102 within a service area (e.g., a cell or cell sector) via a wireless communication link. The base station unit 104 transmits DL communication signals in the time, frequency, and / or spatial domain to serve the remote units 102.

[0055] In one embodiment, the base station unit 104 can receive information from the remote unit 102 on an uplink channel. In some embodiments, the base station unit 104 can determine the SINR for the scheduling layer of the remote unit 102 based on the information received from the remote unit 102 on the uplink channel. Thus, the base station unit 104 can be used to determine the SINR.

[0056] In one embodiment, the remote unit 102 can determine the configuration of the downlink reference signal ports. In various embodiments, the remote unit 102 can measure the SINR of each layer of multiple layers based on this configuration. Thus, the remote unit 102 can be used to measure the SINR.

[0057] In some embodiments, the remote unit 102 may determine the scheduled PRB locations and bandwidth. In some embodiments, the remote unit 102 may determine the relevant DMRS port index within the PRB for PTRS based on the scheduled PRB locations and bandwidth. Accordingly, the remote unit 102 may be used to determine the association between DMRS and PTRS.

[0058] Figure 2 Depicts one embodiment of an apparatus 200 that may be used to determine the association between DMRS and PTRS. The apparatus 200 includes one embodiment of the remote unit 102. Additionally, the remote unit 102 may include a processor 202, a memory 204, an input device 206, a display 208, a transmitter 210, and a receiver 212. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touch screen. In certain embodiments, the remote unit 102 may not include any input device 206 and / or display 208. In various embodiments, the remote unit 102 may include one or more of the processor 202, the memory 204, the transmitter 210, and the receiver 212, and may not include the input device 206 and / or display 208.

[0059] In one embodiment, the processor 202 may include any known controller capable of executing computer-readable instructions and / or capable of performing logical operations. For example, the processor 202 may be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), a co-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. In certain embodiments, the processor 202 may determine the configuration of the downlink reference signal ports. In various embodiments, the processor 202 may measure the SINR of each layer in a multi-layer based on the configuration. In one embodiment, the processor 202 may determine the scheduled PRB locations and bandwidth. In some embodiments, the processor 202 may determine the relevant DMRS port index within the PRB for PTRS based on the scheduled PRB locations and bandwidth. The processor 202 is communicatively coupled to the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212.

[0060] In one embodiment, the memory 204 is a computer-readable storage medium. In some embodiments, the memory 204 includes volatile computer storage media. For example, the memory 204 may include RAM, which includes dynamic RAM ("DRAM"), synchronous dynamic RAM ("SDRAM"), and / or static RAM ("SRAM"). In some embodiments, the memory 204 includes non-volatile computer storage media. For example, the memory 204 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, the memory 204 also stores program code and associated data, such as an operating system or other controller algorithms operating on the remote unit 102.

[0061] In one embodiment, the input device 206 may include any known computer input device, including a touchpad, 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 touchscreen or a similar touch-sensitive display. In some embodiments, the input device 206 includes a touchscreen such that text can be input using a virtual keyboard displayed on the touchscreen and / or by handwriting on the touchscreen. In some embodiments, the input device 206 includes two or more different devices such as a keyboard and a touchpad.

[0062] In one embodiment, the display 208 may include any known electronically controllable display or display device. The display 208 may be designed to output visual, auditory, and / or tactile signals. In some embodiments, the display 208 includes an electronic display capable of outputting visual data to a user. For example, the display 208 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or a similar display device capable of outputting images, text, etc. to a user. As another non-limiting example, the display 208 may include a wearable display such as a smartwatch, smart glasses, a head-up display, etc. Additionally, the display 208 may be a component of a smart phone, a personal digital assistant, a television, a desktop computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, etc.

[0063] In some embodiments, the display 208 includes one or more speakers for generating sound. For example, the display 208 can generate an audible alert or notification (e.g., a beep or a chime). In some embodiments, the display 208 includes one or more haptic devices for generating vibration, movement, or other haptic feedback. In some embodiments, all or part of the display 208 can be integrated with the input device 206. For example, the input device 206 and the display 208 can form a touchscreen or a similar touch-sensitive display. In other embodiments, the display 208 can be located near the input device 206.

[0064] The transmitter 210 is used to provide an UL communication signal to the base station unit 104, and the receiver 212 is used to receive a DL communication signal from the base station unit 104. Although only one transmitter 210 and one receiver 212 are illustrated, the remote unit 102 can have any suitable number of transmitters 210 and receivers 212. The transmitter 210 and the receiver 212 can be any suitable type of transmitter and receiver. In one embodiment, the transmitter 210 and the receiver 212 can be part of a transceiver.

[0065] Figure 3 Depicts an embodiment of an apparatus 300 that can be used to determine the association between DMRS and PTRS. An embodiment of the apparatus 300 includes the base station unit 104 and / or an air server. In addition, the base station unit 104 can include a processor 302, a memory 304, an input device 306, a display 308, a transmitter 310, and a receiver 312. It can be understood that the processor 302, the memory 304, the input device 306, the display 308, the transmitter 310, and the receiver 312 can be substantially similar to the processor 202, the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212 of the remote unit 102, respectively.

[0066] In some embodiments, the receiver 312 can receive information from the remote unit 102 on an uplink channel. In certain embodiments, the processor 302 can determine the SINR for the scheduling layer of the remote unit 102 based on the information received from the remote unit 102 on the uplink channel. Although only one transmitter 310 and one receiver 312 are illustrated, the base station unit 104 can have any suitable number of transmitters 310 and receivers 312. The transmitter 310 and the receiver 312 can be any suitable type of transmitter and receiver. In one embodiment, the transmitter 310 and the receiver 312 can be part of a transceiver.

[0067] Figure 4It is a schematic block diagram of an embodiment of the DMRS pattern shown in the figure. Specifically, the DMRS pattern is shown in the set of resource elements 400. Each resource element occupies a symbol 402 in the time domain and a subcarrier 404 in the frequency domain. Fourteen symbols 402 and twelve subcarriers 404 are shown in the set of resource elements 400.

[0068] In some embodiments, DMRS can be used for channel estimation. In one embodiment, a single UE can support up to 8 ports, and multiple UEs can support up to 12 ports. In various embodiments, different antenna ports can be multiplexed by TDM, FDM, CDM, and / or TD / FD-OCC / TDM. As Figure 4 shown in, one embodiment supports 8 ports (e.g., labeled 0, 1, 2, 3, 4, 5, 6, and 7), and FDM, TDM, and FD-OCC can be used to multiplex different DMRS antenna ports.

[0069] In some embodiments, for multi-layer single-user data transmission, all layers can be carried in the same time / frequency resources. In such embodiments, different layers can be multiplexed by using different precoding vectors in the spatial domain. In certain embodiments, the decoding process at the receiver side can include the following three steps.

[0070] In the first step, the receiver can derive the channel response of each antenna port based on the antenna-port-specific orthogonal resources. For example, to derive the channel response h of antenna port 0', the received signals r at all the REs labeled "0 / 1" in Figure 4 are received and combined together.

[0071] In the second step, channel estimation is performed based on the receiver signal r and / or the transmitted signal s. Various algorithms can be used to perform channel estimation (e.g., zero-forcing ("ZF"), minimum mean square error ("MMSE"), etc.). After channel estimation, the estimated channel of each antenna port can be derived. For example, the channel response of antenna port 0 is estimated as h'.

[0072] In the third step, the estimated channel response is used to recover the data. For 4-layer SU-MIMO transmission, the channel responses at antenna ports 0, 1, 2, and 3 can be derived separately and used to construct the receiver-side processing matrix. Based on the data signals (r1, r2,..., r_RX) received at different receiving antenna units, the data can be recovered and input to other processing units.

[0073] In some embodiments, for multi-layer multi-user data transmission, the above three steps can be used with minor variations. The main difference lies in the division of the total number of ports by different UEs. For example, antenna ports 0, 1, 2, and 3 are used for the first UE, and antenna ports 4, 5, 6, and 7 are used for the second UE. The first and second UE data share the same time / frequency resources. The precoding vectors corresponding to antenna ports 0, 1, 2, and 3 are used for the data transmission of the first UE, and the precoding vectors corresponding to antenna ports 4, 5, 6, and 7 are used for the data transmission of the second UE. From a signaling perspective, the UE may need to know the detailed antenna ports for its own use. That is, it is necessary to indicate antenna ports 0, 1, 2, and 3 to the first UE, and it is necessary to indicate antenna ports 4, 5, 6, and 7 to the second UE.

[0074] Figure 5 is a schematic block diagram of an embodiment of the illustrated PTRS pattern. Specifically, the PTRS pattern is illustrated in the set of resource elements 500. Each resource element occupies a symbol 502 in the time domain and a subcarrier 504 in the frequency domain. Fourteen symbols 502 and twelve subcarriers 504 are illustrated in the set of resource elements 500.

[0075] In certain embodiments, PTRS can be used to track the phase difference in the time domain. In various embodiments, PTRS can be mainly used for high speed and larger subcarriers. An embodiment of the PTRS pattern is illustrated in Figure 5 is illustrated.

[0076] In certain embodiments, the time-domain PTRS density is related to the scheduled MCS. Therefore, using the scheduled MCS value and the MCS and / or density mapping configured by RRC, the symbols carrying PTRS in the time domain can be derived.

[0077] In various embodiments, the frequency-domain PTRS density may be related to the scheduled bandwidth. Using the scheduled bandwidth and the bandwidth and / or density mapping configured by RRC, the PRBs carrying PTRS in the frequency domain can be derived. In some embodiments, several factors can be used to determine the PTRS RE position within the PRB carrying PTRS. For example, the PTRS RE position can be near the RE position of the associated DMRS port to provide accurate phase tracking performance. In certain embodiments, PTRS can be shifted or punctured to avoid conflicts with other reference signals such as CSI-RS, SS blocks, and / or PDCCH time and / or frequency resources.

[0078] In one embodiment, due to the separated oscillator, the PTRS port number is related to the transmitter side TRP and / or panel number. In certain MU-MIMO configurations, different users can use separate PTRS due to different precoding vectors. In such an embodiment, multiplexing can be accomplished using FDM, TDM, or CDM.

[0079] In various embodiments, DMRS is used to estimate the channel from one or two symbols carrying DMRS, and interpolation can be used to obtain the channel response in other non-DMRS symbols. In some embodiments, such as with high frequency bands and high speeds, the channel can change more dynamically in the frequency domain. Thus, PTRS can be used to estimate the phase difference and combined with DMRS-based channel estimation to obtain the channel response for all symbols.

[0080] In certain embodiments, for a single UE, multiple DMRS ports form a DMRS port group to perform SU MIMO transmission. The DMRS port group can correspond to the TRP or panel. In various embodiments, a single PTRS port can be used for a single UE, and the PTRS port can be associated with the TRP or panel. As a result, there may be a PTRS port associated with the DMRS port group, and the PTRS port may share the same precoding vector with one of the DMRS ports.

[0081] In a first embodiment for PTRS and DMRS port association, if one DLPTRS port is configured for the DL DMRS port group, then the DL PTRS port and one DL DMRS port in the DL DMRS port group are associated for phase tracking, and the association can be determined in the specification.

[0082] In a second embodiment for PTRS and DMRS port association, if one DLPTRS port is configured for the DL DMRS port group, then the DL PTRS port is associated with one of the following: a first option, the lowest DLDMRS port in the DL DMRS port group; or a second option, one DL DMRS port in the DL DMRS port group in the RB, where one DL DMRS port can vary across the RB.

[0083] In some embodiments, using the first option, DMRS port 0 can be selected to be associated with the PTRS port, i.e., the PTRS port can share the same precoding vector with DMRS port 0. In various embodiments, since the SINR on different DMRS ports may be different and the port with the maximum SINR may change due to different channel characteristics, the PTRS port can be associated with the DMRS port having the maximum SINR.

[0084] In some embodiments, to obtain the maximum SINR for DMRS port 0, precoder permutation can be used. For example, through precoder permutation, DMRS port 0 may always be associated with the maximum SINR of the channel. At the same time, in some embodiments, data layer 0 can also always be associated with the maximum SINR of the channel. In such embodiments, this may result in SINR imbalance among different layers and / or CWs.

[0085] In various embodiments, using the second option, the association between PTRS and DMRS can change with PRB. In such embodiments, this can provide a certain type of frequency-domain diversity. However, it may affect the coexistence of PTRS and other reference signals.

[0086] Figure 6 FIG. is a schematic flowchart illustrating an embodiment of method 600 for exchanging MCS and / or TBS between two CWs.

[0087] In some embodiments, method 600 includes reporting 602 CQI ACK / NACK for two CWs (e.g., in response to channel measurements based on uplink signals and / or channels in a conventional scenario or in a channel reciprocity scenario). In some embodiments, two CWs can be used in response to a rank indication greater than 4, otherwise, one CW can be used.

[0088] In various embodiments, method 600 includes performing 604 CW-to-layer mapping and determining NDI based on the first transmission or retransmission. In some embodiments, in response to completion of the CW-to-layer mapping, method 600 determines 606 whether there is precoder permutation across different codewords. When there are multiple layers for transmission, the precoding matrix contains multiple columns, and each column corresponds to a transmission layer and a precoding vector. As used herein, precoder permutation means swapping (e.g., exchanging) one or more precoding vectors among different transmission layers. When the swapped transmission layers belong to different CWs, there is precoder permutation among different codewords.

[0089] In response to the method 600 determining 606 that there are different precoder permutations among different CWs, the method 600 may exchange 608 the MCS and / or TBS between two CWs and keep the NDI the same within the CWs (e.g., do not exchange the NDI). In another embodiment, the MCS for two CWs may also be recalculated based on the permuted precoding matrix. In one embodiment, the precoder permutation may be a one-to-one permutation, while in another embodiment, the precoder permutation may be a group-to-group permutation. For example, if there are a total of 5 layers for data transmission, layers 0 and 1 may be used for the first codeword ("CW0"), and layers 2, 3, and 4 may be used for the second codeword ("CW1"). If layer 2 is the highest SINR layer (e.g., layer 2 has the highest SINR among all layers), the precoding vectors for layers 0 and 2 may be swapped. Additionally, in some embodiments, the precoding vectors for layers 1 and 3 may also be swapped.

[0090] Go to Figure 7 , Figure 7 is a schematic block diagram of an embodiment showing the MCS and TBS in two CWs 700 before exchanging the MCS and TBS. Based on the scheduling of the base station unit 104, CW0 702 is associated with MCS0 / TBS0 / NDI0, and based on the scheduling of the base station unit 104, CW1 704 is associated with MCS1 / TBS1 / NDI1.

[0091] Turn to Figure 8 , Figure 8FIG. 0 is a schematic block diagram illustrating an example of MCS and TBS in two CW 800s after swapping MCS and TBS. If data layer 0 and data layer 3 are swapped such that the maximum SINR is transmitted on data layer 0, the new CW0 802 will be associated with MCS1 / TBS1 / NDI0, and the new CW1 804 will be associated with MCS0 / TBS0 / NDI1. Since data layer 0 shares the same precoding vector as DMRS port 0 and data layer 3 shares the same precoding vector as DMRS port 3, the precoding vectors for DMRS ports 0 and 3 are also swapped. In some embodiments, MCS0, TBS0, MCS1, and / or TBS1 can be recalculated based on the new layer grouping. In certain embodiments, the base station unit 104 can derive the detailed SINR for each layer based on uplink channel measurements in the case of channel reciprocity or per-layer SINR feedback (or other feedback such as CQI) from the UE. In various embodiments, if there is only a CQI report for two CWs as in the conventional case, the two CQI values can be compared. In such embodiments, if the CQI of CW1 is better than the CQI of CW0, a precoder column permutation can be performed between layer 0 and the minimum layer of CW1. In some embodiments, if there is a precoder permutation within a single CW, MCS / TBS selection can be performed as in the conventional case.

[0092] Return Figure 6 , in response to method 600 determining 606 that there are no different precoder permutations across different CWs, method 600 can map 610 MCS and / or TBS without swapping (e.g., ACK / NACK feedback for two CWs can be performed as in the conventional case). In certain embodiments, the CW can be a retransmission with NACK feedback, and the corresponding retransmission can be indicated via NDI for each CW. In some embodiments, method 600 can be transparent to the UE without using additional signaling overhead; however, there may be a mismatch between the swapped MCS / TBS and the channel characteristics.

[0093] Go to Figure 9 , Figure 9 FIG. 12 is a schematic flowchart illustrating an example of method 900 for precoder permutation. Method 900 can include the UE measuring 902 the channel response based on the configured CSI-RS. Method 900 can also include the UE determining 904 the reported rank based on the measured channel response. Method 900 can include the UE calculating 906 the SINR value for each layer. In certain embodiments, instead of calculating 906 the SINR, the UE can calculate another value such as CQI, singular value, etc.

[0094] Method 900 determines 908 whether the rank is greater than 4. In response to method 900 determining 908 that the rank is greater than 4, method 900 may map 910 the first floor (e.g., the rounded-down (number of layers / 2)) layers to CW0, and the remaining layers to CW1. For example, when the rank is 5, layers 0 and 1 may be mapped to CW0, and layers 2, 3, and 4 may be mapped to CW1. In some embodiments, method 900 may map the layers in other ways. In response to method 900 determining 908 that the rank is less than or equal to 4, method 900 may map 912 all layers to CW0. For example, when the rank is 4, layers 0, 1, 2, and 3 may be mapped to CW0.

[0095] Method 900 may determine 914 whether the layer with the maximum SINR is layer 0. In response to method 900 determining 914 that the layer with the maximum SINR is not layer 0, method 900 may perform 916 a layer permutation between layer 0 and the layer with the maximum SINR. In certain embodiments, the layer permutation may be performed between the layer groups of CW0 and CW1, especially if the number of layers of the two CWs is the same. Method 900 may calculate 918 the CQI based on the permuted layers for one or both CWs. In some embodiments, if the layers of the two CWs are the same, method 900 may determine the CQI for one or both CWs based on the layer mapping before the permutation. In various embodiments, method 900 may report 920 the CQI, RI, PMI, and / or the permutation information. In certain embodiments, the UE may report the layer with the maximum SINR before the permutation for permutation reporting. For example, if the maximum transmission layer is 8, 3 bits may be used to indicate which layer is permuted. If the indication is 100, it may mean that layer 4 is changed through layer 0. The reported CQI may be the CQI determined according to the calculation 918, and the RI may be the rank determined according to the determination 904. In some embodiments, the PMI before the permutation may be reported so that the codebook design may not be affected.

[0096] In some embodiments, the base station unit 104 may reconstruct the precoding vector based on the reported PMI and the permutation report. For example, if 010 is reported in the permutation report, columns 0 and 4 in the reported precoding matrix may be interchanged. If the permutation is a group permutation and 100 is reported in the permutation report, it may mean that layer 4 is the layer with the maximum SINR, and if layer 4 belongs to CW1, columns 0, 1, 2, and 3 and columns 4, 5, 6, and 7 in the reported precoding matrix may be interchanged respectively.

[0097] In some embodiments, when necessary, the base station unit 104 updates the constructed precoding vector and the reported CQI and / or RI. In some embodiments, method 900 may have a reported CQI value that matches the permuted precoding vector; however, compared to method 600, method 900 may increase the complexity and overhead of the UE.

[0098] In some embodiments, for the case of MU, each UE may have its own UE-specific PTRS port. In such embodiments, precoder column permutation can be performed for each user. In various embodiments, if the CW of each MU UE is restricted to 1, precoder column permutation can be performed for each UE on the transmitter side, and since the same MCS / TBS / CQI for different layers of a single CW of each UE, it may not affect the performance. For example, if ports 0 and 1 are used for UE1, and ports 2 and 3 are used for UE2. For UE1, if port 1 has a higher SINR than port 0, permutation between port 0 and port 1 can be performed on the transmitter side. For UE2, if port 3 has the highest SINR, permutation between port 2 and port 3 can also be performed on the transmitter side. If two codewords are used for each MU UE, transmitter-side permutation and UE-side permutation can be used.

[0099] In some embodiments, transmitter-side permutation for the scheduled MU UE can be used. For example, ports 0 and 1 and CW0 and CW1 can be used for UE1, and ports 2 and 3 and CW0 and CW1 can be used for UE2. UE1 and UE2 can be scheduled in the same time and / or frequency resources. In such embodiments, since the same time / frequency resources are used, the transmission power of both UE1 and UE2 can be reduced by 3 dB. In some embodiments, UE1 has its own UE-specific PTRS port 0 for phase tracking, and UE2 also has its own UE-specific PTRS port 0 for phase tracking. For UE1, if the SINR of port 0 is less than the SINR of port 1, precoder column permutation of layer 0 and layer 1 can be performed. In addition, MCS / TBS exchange can be performed for the two CWs of UE1. UE2 can use a similar operation. In various embodiments, UE-side permutation of each scheduled MU UE can be used.

[0100] In some embodiments, the frequency-domain PTRS density may be related to the scheduled bandwidth. That is, based on the bandwidth-density mapping table configured by RRC, using the scheduled bandwidth in the DCI format, the UE can derive the PRBs carrying PTRS. For example, if the scheduled bandwidth is 30 PRBs and the corresponding density through the mapping table is 1 / 3, the UE can derive that PRBs 0, 3, 6, 9, 12, 15, 18, 21, 24, and 27 are the PRBs carrying PTRS. For a single PTRS port, a single RE in the PRB can be used. In such an embodiment, the detailed PTRS RE location may be related to the associated DMRS port.

[0101] In various embodiments, the UE may be assigned to multiple DMRS ports for spatial multiplexing operations. Different DMRS ports can be multiplexed by FDM, TDM, and / or CDM to provide accurate channel estimation. For example, DMRS port 0 may be associated with the REs including 0 / 1 and 4 / 5 in Figure 4 and DMRS port 2 may be associated with the REs including 2 / 3 and 6 / 7 in Figure 4 . If PTRS port 0 is associated with DMRS port 0, the PTRS RE location should be restricted to the REs including 0 / 1 and 4 / 5 due to the similar channel characteristics of adjacent REs, and the precoding vectors for PTRS port 0 and DMRS port 0 should be the same. If PTRS port 0 is associated with DMRS port 2, the PTRS RE location should be restricted to the REs including 2 / 3 and 6 / 7, and PTRS port 0 shares the same precoding vector with DMRS port 2.

[0102] In various embodiments, the associated DMRS port for PTRS may change with the PRB. This may mean that the precoding vector and RE location of the PTRS port may change with the PRB. In such an embodiment, frequency-domain diversity can be achieved because this is similar to the precoder cycling in the frequency domain.

[0103] In some embodiments, the RE location within the PRB changes with the PRB. This may mean that the frequency-domain distribution of PTRS port 0 is not uniform. In addition, if interpolation is used in the frequency domain, there may be some impact on performance due to the non-uniform distribution. In some embodiments, the coexistence between PTRS and other RSs and / or channels may be common. The possible coexisting RSs and / or channels may be CSI-RS, SS block, PDCCH control resource, and / or data. If PTRS always has the lowest priority, there may be no impact on other RSs and / or channels. However, other RSs and / or channels can use puncturing, shifting, and / or discarding to avoid PTRS time / frequency resources. In various embodiments, there may be different puncturing, shifting, and / or discarding patterns in the PRBs carrying different PTRS.

[0104] In some embodiments, the UE may know the RE locations of the PRBs carrying the PTRS. In certain embodiments, there may be an implicit way to derive the associated DMRS ports for each PRB carrying the PTRS. For example, the UE may derive the associated DMRS ports for each PRB carrying the PTRS based on the scheduled PRB locations and bandwidth. In various embodiments, the PRB carrying the PTRS with the smallest PRB index is associated with DMRS port 0. In various embodiments, as the PRB index increases, the associated DMRS port index may also increase ((e.g., 0, 1, … maximum DMRS port index, 0, 1, ...), which are respectively mapped to each PRB carrying the PTRS). In some embodiments, the maximum DMRS port may be indicated in the DCI. As another example, deriving the associated DMRS ports for each PRB carrying the PTRS may be cell-specific and may be derived by extending the PRBs carrying the PTRS to the total system bandwidth (e.g., by mapping the DMRS port indices (0, 1, …, maximum DMRS port index, 0, 1, ...) to the PRBs carrying the PRRS of the system bandwidth). For a single UE, a portion corresponding to the scheduled bandwidth may be used. For example, the DMRS port indices may be 0, 1, …, maximum DMRS port index, and the PRB indices of the PRBs carrying the PTRS starting from the carrier bandwidth or bandwidth part may be indexed as 0, 1, 2, ..., maximum PRB index carrying the PTRS. If the bandwidth part allocated to the UE overlaps with the PRBs i, i+1, …, j carrying the PTRS, the associated DMRS ports are respectively i mod (max_DMRS_port_index + 1), (i mod (max_DMRS_port_index + 1)) + 1, …. In certain embodiments, the difference between the UE-specific and cell-specific derivations of the associated DMRS ports for each PRB carrying the PTRS may be that the starting DMRS port index is changed and / or it may be better to randomize the cell-specific starting DMRS port index.

[0105] In some embodiments, explicit signaling may be used to indicate the associated DMRS port index for the PRB index of the minimum PTRS carrier. Such signaling may be performed using DCI signaling and / or RRC signaling. In certain embodiments, if the possible maximum DMRS port for a single UE is 8, 3 bits may be used for signaling.

[0106] In various embodiments, a hopping pattern may be used. In such embodiments, the hopping step size may be any suitable value, such as 0, 1, 2, etc. In some embodiments, 0 may indicate the DMRS port index difference between two CWs. For example, if there are two CWs, CW0 is associated with DMRS port indices 0, 1, and 2, and CW1 is associated with DMRS port indices 3, 4, 5, and 6, then the first, third, and fifth PRBs carrying PTRS are associated with DMRS ports having indices 0, 1, and 2 respectively, and the second, fourth, sixth, and eighth PRBs carrying PTRS are associated with DMRS ports having indices 3, 4, 5, and 6 respectively. In various embodiments, the PRBs carrying PTRS are re-indexed as 0, 1, 2, …. In such embodiments, a hopping step size of 1 indicates that the difference between two adjacent DMRS port indices is one times the difference between the indices of the re-indexed adjacent PRBs carrying PTRS. Additionally, a hopping step size of 2 indicates that the difference between two adjacent DMRS ports is two times the difference between the indices of the re-indexed PRBs carrying PTRS. For example, if there are DMRS ports 0, 1, 2, and 3, and the PRB indices of the PRBs carrying PTRS are 00, 01, 02, 03, and 04, then when the hopping step size is 2, the PTRS PRB index 00 is associated with DMRS port 0, the PTRS PRB index 01 is associated with DMRS port 2, the PTRS PRB index 02 is associated with DMRS port 0, the PTRS PRB index 03 is associated with DMRS port 2, and the PTRS PRB index 04 is associated with DMRS port 0. As another example, if there are DMRS ports 0, 1, 2, and 3, and the PRB indices of the PRBs carrying PTRS are 00, 01, 02, 03, and 04, then when the hopping step size is 1, the PTRS PRB index 00 is associated with DMRS port 0, the PTRS PRB index 01 is associated with DMRS port 1, the PTRS PRB index 02 is associated with DMRS port 2, the PTRS PRB index 03 is associated with DMRS port 3, and the PTRS PRB index 04 is associated with DMRS port 0.

[0107] In one embodiment, the hopping information may be signaled explicitly using DCI signaling and / or RRC signaling. In such an embodiment, 1 or 2 bits may be used to signal the hopping information. In various embodiments, the hopping information may be determined implicitly based on the scheduled bandwidth and the maximum DMRS port index. For example, if the number of PRBs carrying PTRS is greater than the maximum DMRS port index, then hopping_step = 1; otherwise, hopping_step = ceil(max_DMRS_port_index / PTRS_bearing_PRB_number) or floor(max_DMRS_port_index / PTRS_bearing_PRB_number).

[0108] In some embodiments, a default hopping step may be used. For example, if there are two codewords, the hopping step may be equal to 0 as a default behavior, and if there is only one codeword, the hopping step may be equal to 1 as a default behavior. In certain embodiments, if the associated DMRS port in the PRB carrying PTRS is known, the RE location may be determined.

[0109] In certain embodiments, the PTRS for the UE may be associated with the DMRS port having the maximum SINR in each PRB carrying PRTS. In such an embodiment, there may be multiple ways to derive the associated DMRS port in each PRB carrying PTRS. One way to derive the associated DMRS port in each PRB carrying PTRS may be based on UE blind detection. Using blind detection, the UE may perform channel estimation for all assigned DMRS ports in the scheduled subframe for each PRB carrying PTRS, and based on the channel estimation results, the maximum SINR DMRS port of the PRB carrying PTRS may be derived. Another way to derive the associated DMRS port in each PRB carrying PTRS may be based on the indication of the associated DMRS port of each PRB carrying PTRS by the base station unit 104. However, this may incur a large overhead.

[0110] In some embodiments, the coexistence of other RSs and / or channels is known to the base station unit 104 before scheduling, so puncturing, shifting, and / or discarding of the corresponding RSs and / or channels may be done by the base station unit 104. In certain embodiments, the UE may derive the puncturing, shifting, and / or discarding behavior after decoding the DCI signaling based on predefined rules, which may avoid false detection.

[0111] In various embodiments, each UE may have UE-specific PTRS. Additionally, the MU UE may have different transmission layers. In some embodiments, from the perspective of DMRS, the MU may be transparent to the UE. In this case, the DMRS ports of a single UE and multiple UEs may occupy the same time / frequency resources, and the DMRS ports may be code-division multiplexed. In certain embodiments, the PTRS RE positions may be restricted to be associated with the minimum DMRS port index of each UE. In some embodiments, the precoding vectors may be different for different PRBs carrying PRTS. Figure 10 and 11 illustrative examples in.

[0112] Figure 10 is a schematic block diagram illustrating an embodiment of DMRS for multiple users. Specifically, the DMRS pattern is illustrated in a set of resource elements 1000. Each resource element occupies symbol 1002 in the time domain and subcarrier 1004 in the frequency domain. Fourteen symbols 1002 and twelve subcarriers 1004 are illustrated in the set of resource elements 1000. UE1 is assigned DMRS port 0, UE2 is assigned DMRS port 2, and UE3 (e.g., the third UE) is assigned DMRS ports 2 and 3. The DMRS of these UEs occupies the same time / frequency resources, as Figure 10 shown in.

[0113] Figure 11 is a schematic block diagram illustrating an embodiment of PTRS for multiple users. Specifically, the PTRS pattern is illustrated in a set of resource elements 1100. Each resource element occupies symbol 1102 in the time domain and subcarrier 1104 in the frequency domain. Fourteen symbols 1102 and twelve subcarriers 1104 are illustrated in the set of resource elements 1100. In some embodiments, each UE has its own UE-specific PTRS. The PTRS shares the same RE position, which is RE position 0. The precoding vector of the UE-specific PTRS may be related to the associated DMRS port. According to the PRB index carrying the PTRS as in the SU case, the PTRS port 0 of UE1 may share the same precoding vector as DMRS port 0, the PTRS port 0 of UE2 may share the same precoding vector as DMRS port 1, and the PTRS port 0 of the UE may share the same precoding vector as DMRS port 2 or 3.

[0114] In some embodiments, from the perspective of DMRS, the MU may be opaque to the UE. In such cases, both the DMRS and PTRS occupancy need to be notified to the co-scheduled UE for rate matching. In some embodiments, for the co-scheduled UE, the PTRS RE position hopping pattern may be known. In such cases, due to the fact that the MU UE may only have a partially overlapping bandwidth, a cell-specific PTRS RE position hopping pattern based on the system bandwidth can be used. In various embodiments, there may be a default pattern hopping step, or this hopping step can be explicitly signaled via RRC signaling and / or DCI signaling.

[0115] In various embodiments, DFTS-OFDM can be used. In such embodiments, there may be pre-DFT insertion of the PTRS. Additionally, if the associated DMRS port changes, the multiplexing of data and PTRS may change with the PRB. For example, in PRB 0 carrying the PTRS, PTRS port 0 may be associated with DMRS port 0 and multiplexed with data layer 0, while in PRB 1 carrying the PTRS, PTRS port 0 may be associated with DMRS port 1 and multiplexed with data layer 1. In some embodiments, the PTRS may always be multiplexed with data layer 0 if it is always associated with DMRS port 0. In some embodiments, pre-coder column permutation can be used to produce the maximum SINR for DMRS port 0. MCS and / or CQI exchange operations at the transmitter side and the UE side can also be used. It can be understood that the various embodiments described herein can be used for DL and / or UL.

[0116] Figure 12 is a schematic flowchart illustrating an embodiment of method 1200 for determining SINR. In some embodiments, method 1200 is performed by an apparatus such as base station unit 104. In certain embodiments, method 1200 can be performed by a processor executing program code, e.g., a microcontroller, a microprocessor, a CPU, a processor, a GPU, an auxiliary processing unit, an FPGA, etc.

[0117] Method 1200 may include receiving 1202 information from remote unit 102 on an uplink channel. In certain embodiments, method 1200 includes determining 1204 the signal-to-interference-plus-noise ratio for the scheduling layer of remote unit 102 based on the information received from the remote unit on the uplink channel.

[0118] In one embodiment, the information from the remote unit on the uplink channel includes a report from the remote unit. In certain embodiments, the report includes a channel quality indication report corresponding to two codewords. In various embodiments, in response to the channel quality indication of the second codeword among the two codewords indicating better channel quality than the channel quality indication of the first codeword among the two codewords, method 1200 includes swapping the modulation and coding scheme, transport block size, or a combination thereof of the first and second codewords in the downlink control information.

[0119] In some embodiments, in response to the channel quality indication of the second codeword among the two codewords indicating better channel quality than the channel quality indication of the first codeword among the two codewords, method 1200 includes performing a precoder column permutation for layer 0 and the minimum layer of the second codeword. In one embodiment, the report includes a signal-to-interference-plus-noise ratio report or a channel quality indication report for each layer of multiple layers. In another embodiment, in response to the signal-to-interference-plus-noise ratio report of layer 0 not being the best signal-to-interference-plus-noise ratio report or the channel quality indication report of layer 0 not being the best channel quality indication report, method 1200 includes performing a precoder column permutation for layer 0 and the layer with the best signal-to-interference-plus-noise ratio report or the best channel quality indication report.

[0120] In certain embodiments, in response to the layer with the best signal-to-interference-plus-noise ratio report or the best channel quality indication report belonging to the second codeword, method 1200 includes swapping the modulation and coding scheme, transport block size, or a combination thereof of the first codeword and the second codeword in the downlink control information. In various embodiments, the signal-to-interference-plus-noise ratio is based on measurements of the uplink channel. In one embodiment, in response to the signal-to-interference-plus-noise ratio of layer 0 based on the measurement not being the maximum signal-to-interference-plus-noise ratio, method 1200 includes performing a precoder column permutation for layer 0 and the layer with the maximum signal-to-interference-plus-noise ratio. In some embodiments, in response to the maximum signal-to-interference-plus-noise ratio based on the measurement belonging to the second codeword, method 1200 includes performing a precoder column permutation between the first codeword and the second codeword.

[0121] In various embodiments, in response to the maximum signal-to-interference-plus-noise ratio based on the measurement belonging to the second codeword, method 1200 includes swapping the modulation and coding scheme, transport block size, or a combination thereof of the first codeword and the second codeword in the downlink control information. In certain embodiments, in response to the maximum signal-to-interference-plus-noise ratio based on the measurement belonging to the second codeword, method 1200 includes recalculating the modulation and coding scheme, transport block size, or a combination thereof of the first codeword and indicating the modulation and coding scheme, transport block size, or a combination thereof in the downlink control information.

[0122] Figure 13FIG. is a schematic flow chart illustrating an embodiment of method 1300 for measuring SINR. In some embodiments, method 1300 is performed by a device such as remote unit 102. In certain embodiments, method 1300 may be performed by a processor executing program code, e.g., a microcontroller, a microprocessor, a CPU, a processor, a GPU, an auxiliary processing unit, an FPGA, etc.

[0123] Method 1300 may include determining 1302 the configuration of the downlink reference signal ports. In various embodiments, method 1300 includes measuring 1304 the signal-to-interference-plus-noise ratio of each of the multiple layers based on the configuration.

[0124] In one embodiment, method 1300 includes performing a mapping of codewords to layers based on the number of layers in the multiple layers. In certain embodiments, method 1300 includes transmitting a report including the layer with the maximum signal-to-interference-plus-noise ratio based on measuring the signal-to-interference-plus-noise ratio of each layer.

[0125] In various embodiments, method 1300 includes determining a precoding matrix based on measuring the signal-to-interference-plus-noise ratio of each layer. In some embodiments, each column of the precoding matrix includes a precoding vector, and each precoding vector is determined based on the corresponding layer of the multiple layers. In one embodiment, in response to the maximum signal-to-interference-plus-noise ratio corresponding to a layer other than layer 0, method 1300 includes swapping the precoding vector of layer 0 with the precoding vector of the layer having the maximum signal-to-interference-plus-noise ratio in the precoding matrix to produce a permuted precoding matrix. In yet another embodiment, method 1300 includes determining a channel quality indication for each of the multiple codewords based on the permuted precoding matrix. In certain embodiments, method 1300 includes transmitting a report including the channel quality indication for each codeword. In various embodiments, the base station unit determines the permuted precoding matrix based on the layer having the maximum signal-to-interference-plus-noise ratio and the precoding matrix. In one embodiment, method 1300 includes transmitting a report including the precoding matrix.

[0126] Figure 14 FIG. is a schematic flow chart illustrating an embodiment of method 1400 for determining the association between DMRS and PTRS. In some embodiments, method 1400 is performed by a device such as remote unit 102. In certain embodiments, method 1400 may be performed by a processor executing program code, e.g., a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, an FPGA, etc.

[0127] Method 1400 may include determining 1402 the location and bandwidth of the scheduled physical resource blocks. In some embodiments, method 1400 includes determining 1404 the associated demodulation reference signal port index within the physical resource block for the phase-tracking reference signal based on the scheduled physical resource block location and bandwidth.

[0128] In one embodiment, method 1400 includes associating the phase-tracking reference signal with the demodulation reference signal port of the physical resource block carrying the phase-tracking reference signal having the smallest physical resource block index. In some embodiments, method 1400 includes associating the phase-tracking reference signal with the smallest demodulation reference signal port index of the physical resource block carrying the phase-tracking reference signal having the smallest physical resource block index.

[0129] In various embodiments, method 1400 includes associating the phase-tracking reference signal with the demodulation reference signal port index of the physical resource block carrying the phase-tracking reference signal having the smallest physical resource block index based on the scheduled physical resource block location in a carrier or bandwidth part. In some embodiments, method 1400 includes associating the phase-tracking reference signal with the demodulation reference signal port indicated in the downlink control information, radio resource control, or a combination thereof of the physical resource block carrying the phase-tracking reference signal having the smallest physical resource block index. In one embodiment, method 1400 includes determining the demodulation reference signal port index difference of adjacent physical resource blocks carrying the phase-tracking reference signal. In another embodiment, the determined demodulation reference signal port index difference is based on the demodulation reference signal port difference between two codewords. In some embodiments, the determined demodulation reference signal port index difference is based on a default value. In various embodiments, the determined demodulation reference signal port index difference is based on signaling through the downlink control information, radio resource control, or a combination thereof. In one embodiment, the signaling is part of an uplink grant or downlink assignment.

[0130] In some embodiments, method 1400 includes determining the phase-tracking reference signal resource element location within the physical resource block based on the demodulation reference signal port index. In some embodiments, method 1400 includes determining that the phase-tracking reference signal precoding vector is the same as the precoding vector of the associated demodulation reference signal port. In various embodiments, method 1400 includes determining the phase-tracking reference signal resource element location within the physical resource block based on the smallest demodulation reference signal port index. In some embodiments, method 1400 includes determining the phase-tracking reference signal resource element location within the physical resource block based on radio resource control signaling.

[0131] The embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. Thus, the scope of the invention is 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.

Claims

1. A method, comprising: Determining a configuration of a downlink reference signal port; Measuring a signal-to-interference-plus-noise ratio (SINR) of each of a plurality of layers based on the configuration; Determining a precoding matrix based on measuring the SINR of each layer; Reporting a layer with the maximum SINR based on measuring the SINR of each layer; And In response to the maximum SINR corresponding to a layer other than layer 0, swapping a precoding vector for layer 0 and a precoding vector for the layer with the maximum SINR in the precoding matrix, thereby generating a permuted precoding matrix.

2. The method according to claim 1, further comprising performing a mapping of codewords to layers based on the number of layers among the plurality of layers.

3. The method according to claim 1, wherein Each column of the precoding matrix includes the precoding vector, and each of the precoding vectors is determined based on the corresponding layer among the plurality of layers.

4. The method according to claim 1, further comprising determining a channel quality indicator for each of a plurality of codewords based on the permuted precoding matrix.

5. The method according to claim 4, further comprising reporting the channel quality indicator for each codeword.

6. The method according to claim 1, wherein The permuted precoding matrix is determined based on the layer with the maximum SINR and the precoding matrix.

7. The method according to claim 1, further comprising reporting the precoding matrix.

8. An apparatus, comprising: A processor: Determining a configuration of a downlink reference signal port; And Measuring a SINR of each of a plurality of layers according to the configuration; Determining a precoding matrix based on measuring the SINR of each layer; And A transmitter, the transmitter transmitting a report including the layer with the maximum SINR based on measuring the SINR of each layer, Wherein, in response to the maximum SINR corresponding to a layer other than layer 0, swapping a precoding vector for layer 0 and a precoding vector for the layer with the maximum SINR in the precoding matrix, thereby generating a permuted precoding matrix.

9. The apparatus according to claim 8, wherein, The processor performs a mapping of codewords to layers based on the number of layers among the plurality of layers.

10. The apparatus according to claim 8, wherein, Each column of the precoding matrix includes the precoding vector, and each of the precoding vectors is determined based on the corresponding layer among the plurality of layers.

11. The apparatus according to claim 8, wherein, The processor determines a channel quality indicator for each of a plurality of codewords based on the permuted precoding matrix.

12. The apparatus according to claim 11, the transmitter transmitting a report including the channel quality indicator for each codeword.

13. The apparatus according to claim 8, wherein The permuted precoding matrix is determined based on the layer with the maximum SINR and the precoding matrix.

14. The apparatus according to claim 8, the transmitter transmitting a report including the precoding matrix.

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