Method and apparatus for supporting power amplifier aware modulation in wireless communication system

Abstract

The present disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as Long Term Evolution (LTE). Relates to a method and apparatus for transmission symbol modulation taking into account distortion introduced by a power amplifier (PA). A user equipment (UE) includes a transceiver and a processor. The transceiver is configured to: transmit UE capability information to a base station (BS), the UE capability information indicating that an adjusted symbol constellation is supported, where the adjusted symbol constellation is adjusted to pre-compensate for a distortion effect of a power amplifier (PA) in the transceiver; and receiving a modulation and coding scheme (MCS) indication from the BS. The processor is configured to: determine an adjusted symbol constellation based on the MCS indication; and generating an adjustment symbol from the input bit according to the determined adjusted symbol constellation. The transceiver is further configured to transmit the modulation symbols to the BS.

Description

TECHNICAL FIELD

[0001] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 524,183, filed June 29, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates generally to symbol generation in a wireless communication system. Embodiments of the present disclosure relate to methods and apparatuses for determining a modulation scheme with an adjusted symbol constellation to pre-compensate for distortion effects of a power amplifier. BACKGROUND

[0003] In view of the development of wireless communication generation after generation, technologies have been developed mainly for services targeting humans, such as voice calls, multimedia services, and data services. As 5G (5th generation) communication systems are commercialized, it is expected that the number of connected devices will grow exponentially. These devices will increasingly be connected to communication networks. Examples of connected things can include vehicles, robots, drones, home appliances, displays, and smart sensors connected to various infrastructures, construction machinery, and factory equipment. It is expected that mobile devices will develop in various forms, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (6th generation) era, there have been ongoing efforts to develop improved 6G communication systems. For these reasons, 6G communication systems are referred to as beyond 5G systems.

[0004] It is expected that 6G communication systems, which are to be commercialized around 2030, will have a peak data rate of terabit (1 trillion bits) and a wireless latency of less than 100 microseconds, and thus will be 50 times faster and have 1 / 10th the wireless latency of 5G communication systems.

[0005] In order to achieve such a high data rate and ultra-low latency, it has been considered to implement 6G communication systems in a terahertz band (e.g., 95 GHz to 3 THz bands). It is expected that, since path loss and atmospheric absorption are more severe in the terahertz band than the mmWave frequency band introduced in 5G, technologies capable of securing signal transmission distance (i.e., coverage) will become more crucial. As major technologies for securing coverage, it is necessary to develop radio frequency (RF) elements, antennas, new waveforms having better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and massive multiple input multiple output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, and multi-antenna transmission techniques such as large-scale antennas. In addition, there has been ongoing discussion in the industry about new technologies for improving coverage of terahertz band signals, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS).

[0006] In addition, in order to improve the spectral efficiency and overall network performance, the following technologies have been developed for 6G communication systems: a full duplex technology for enabling uplink transmission and downlink transmission to use the same frequency resource at the same time; a network technology for comprehensively utilizing satellites, high altitude platform stations (HAPS), etc.; an improved network structure for supporting mobile base stations, etc., and implementing network operation optimization and automation, etc.; a dynamic spectrum sharing technology via collision avoidance based on spectrum usage prediction; use of AI in wireless communications for improving overall network operations by utilizing artificial intelligence (AI) from the design stage of developing 6G and internalizing end-to-end AI support functions; and next-generation distributed computing technology for overcoming limitations of UE computing capability through ultra-high-performance communication and computing resources available on a network, such as mobile edge computing (MEC), cloud, etc. In addition, the industry is continuously attempting to strengthen connectivity between devices, optimize networks, promote softwareization of network entities, and increase openness of wireless communications by designing new protocols to be used in 6G communication systems, developing mechanisms for implementing a hardware-based secure environment and secure use of data, and developing technologies for maintaining privacy.

[0007] It is expected that research and development of 6G communication systems in the field of ultra-connectivity, including person-to-machine (P2M) and machine-to-machine (M2M), will allow next-generation ultra-connectivity experiences. In particular, it is expected that services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital twins can be provided through 6G communication systems. In addition, services such as remote surgery for security and reliability enhancement, industrial automation, and emergency response will be provided through 6G communication systems, so that the technology can be applied to various fields such as industry, medical care, automobiles, and home appliances. SUMMARY

[0008] [TECHNICAL PROBLEM]

[0009] The disclosure relates to a wireless communication system, and more particularly, the disclosure relates to supporting power amplifier-aware modulation in wireless communications.

[0010] [SOLUTION TO THE PROBLEM]

[0011] Embodiments of the disclosure provide a method and apparatus that facilitates symbol modulation that takes into account distortion introduced by a PA in a wireless transmission device.

[0012] In one embodiment, a user equipment (UE) includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to transmit, to a BS, UE capability information indicating support of an adjusted symbol constellation, where the adjusted symbol constellation is adjusted for pre-compensating for distortion effects of a PA in the transceiver, and receive, from the BS, a MCS indication. The processor is configured to determine the adjusted symbol constellation based on the MCS indication, and generate adjusted symbols from input bits according to the determined adjusted symbol constellation. The transceiver is further configured to transmit the modulated symbols to the BS.

[0013] In another embodiment, a BS includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive, from a UE, UE capability information indicating an adjusted symbol constellation supported by the UE, where the adjusted symbol constellation is adjusted for pre-compensating for distortion effects of a PA in a transceiver of the UE. The processor is configured to generate a MCS indication based on the UE capability information. The transceiver is further configured to transmit the MCS indication to the UE, and receive, from the UE, modulated symbols corresponding to the adjusted symbol constellation corresponding to the MCS indication.

[0014] In another embodiment, an operation method of a UE includes transmitting, to a BS, UE capability information indicating an adjusted symbol constellation supported by the UE, where the adjusted symbol constellation is adjusted for pre-compensating for distortion effects of a PA in a transceiver of the UE, receiving, from the BS, a MCS indication, determining the adjusted symbol constellation based on the MCS indication, generating adjusted symbols from input bits according to the determined adjusted symbol constellation, and transmitting the modulated symbols to the BS.

[0015] Other technical features can be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0016] Before proceeding with the following detailed description, it may be advantageous to define certain words and phrases used throughout this patent document. The term “connection” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not these elements are physically in contact with each other. The terms “transmit,” “receive,” and “communicate,” and their derivatives include both direct and indirect communication. The terms “comprise” and “include,” and their derivatives mean non-restrictive inclusion. The term “or” is inclusive, meaning and / or. The phrase “associated with,” and its derivatives mean including, being included within, interconnected with, containing, being contained within, connected to or connected with, coupled to or coupled with, capable of communicating with, cooperating with, intertwined, juxtaposed, proximate, bound to or bound with, having, possessing the attributes of, having a relationship with, or similar meanings. The term “controller” refers to any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, local or remote. The phrase “at least one,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be required. For example, “at least one of A, B, and C” includes any of the following combinations: A; B; C; A and B; A and C; B and C; and A and B and C. As used herein, terms such as “first” and “second” can be used simply to distinguish the corresponding component from another component without otherwise limiting the component (e.g., importance or order). It should be understood that if an element (e.g., a first element) is referred to as “coupled to another element (e.g., a second element),” “coupled to another element (e.g., a second element),” “connected to another element (e.g., a second element),” or “connected to another element (e.g., a second element)” (with or without the terms “operably” or “communicatingly”), it means that the element may be coupled to another element directly (e.g., wired), wirelessly, or via a third element.

[0017] As used herein, the term "module" can include units implemented in hardware, software, or firmware, and is used interchangeably with other terms such as "logic," "logic block," "part," or "circuit." A module can be a single integral component adapted to perform one or more functions, or its smallest unit or portion. For example, according to an embodiment, a module can be implemented as an application-specific integrated circuit (ASIC).

[0018] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of media capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A "non-transitory" computer readable medium excludes wired, wireless, optical, or other communication links. A non-transitory computer readable medium includes media where data is permanently stored and media where data is stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0019] The following abbreviations can be referred to within the text: AI (Artificial Intelligence) AM (Amplitude Modulation) BS (Base Station) CE (Control Element) dBm (Decibel per Milliwatt) DCI (Downlink Control Information) IE (Information Element) MCS (Modulation and Coding Scheme) OTA (Over-the-Air Interface) PA (Power Amplifier) PDCCH (Physical Downlink Control Channel) PUSCH (Physical Uplink Shared Channel) PUCCH (Physical Uplink Control Channel) QAM (Quadrature Amplitude Modulation) RRC (Radio Resource Control) SER (Symbol Error Rate) UCI (Uplink Control Information) UE (User Equipment) Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.

[0020] The disclosures of the following documents are incorporated herein by reference in their entirety: [1] 3GPP, TS 38.211, 5G; NR; Physical channels and modulation.

[0021] [2] 3GPP, TS 38.331, 5G; NR; Radio Resource Control (RRC); Protocol specification.

[0022] [3] 3GPP, TS 38.321, 5G; NR; Medium Access Control (MAC); Protocol specification.

[0023] [4] 3GPP, TS 38.214, 5G; NR; Physical layer procedures for data.

[0024] [Advantages of the invention]

[0025] According to embodiments of the disclosure, wireless communications can be efficiently performed. In particular, support for power amplifier aware modulation in wireless communications can be efficiently performed. BRIEF DESCRIPTION OF DRAWINGS

[0026] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals represent like parts: Figure 1 An example wireless network is illustrated in accordance with various embodiments of the present disclosure; Figure 2 An example gNB is illustrated in accordance with embodiments of the present disclosure; Figure 3 An example UE is illustrated in accordance with embodiments of the present disclosure; Figure 4 An example input-output PA characteristic is illustrated in accordance with embodiments of the present disclosure; Figure 5 An example modulation symbol constellation is illustrated in accordance with embodiments of the present disclosure; Figure 6 An example method for UE operation to support different constellations per MCS index for a given modulation order is illustrated in accordance with embodiments of the present disclosure; Figure 7 An example method for BS operation to support different constellations per MCS index for a given modulation order is illustrated in accordance with embodiments of the present disclosure; Figure 8 An example lookup table to facilitate determining a modulation method based on an MCS index is illustrated in accordance with embodiments of the present disclosure; Figure 9 An example input-output PA characteristic for performance evaluation is illustrated in accordance with embodiments of the present disclosure; Figure 10 An example graph of the impact of PA saturation and memory effects on a conventional modulation method is illustrated in accordance with embodiments of the present disclosure; Figure 11 An example system with trainable modulator is shown in accordance with an embodiment of the disclosure; Figure 12 An example plot showing the impact of PA saturation and memory effects on adjusted modulation methods is shown in accordance with an embodiment of the disclosure; Figure 13 An example wireless transmitter (Tx) architecture with DPD is shown in accordance with an embodiment of the disclosure; Figure 14 An example SER plot showing the impact of PA saturation and memory effects on different modulation methods is shown in accordance with an embodiment of the disclosure; Figure 15 An example method for UE operation to support power level based constellation adjustment is shown in accordance with an embodiment of the disclosure; Figure 16 An example method for BS operation to support power level based constellation adjustment is shown in accordance with an embodiment of the disclosure; Figure 17 An example method for UE operation to support power level based constellation adjustment is shown in accordance with an embodiment of the disclosure; Figure 18 An example method for BS operation to support UE initiated fallback to legacy constellation is shown in accordance with an embodiment of the disclosure; Figure 19 An example method for UE operation to support UE initiated fallback to legacy constellation without constellation adjustment is shown in accordance with an embodiment of the disclosure; Figure 20 An example method for BS operation to support BS initiated fallback to legacy constellation is shown in accordance with an embodiment of the disclosure; Figure 21 An example method for UE operation to support BS initiated fallback to legacy constellation is shown in accordance with an embodiment of the disclosure; Figure 22 An example format of a new MAC CE for constellation adjustment indication is shown in accordance with an embodiment of the disclosure; Figure 23 An example format of a new MAC CE for constellation fallback indication is shown in accordance with an embodiment of the disclosure; and Figure 24 An example procedure for symbol modulation that takes into account distortion introduced by a PA in a wireless transmission device is shown in accordance with various embodiments of the disclosure. DETAILED DESCRIPTION

[0027] In a wireless communication system, data bits to be transmitted are encoded and modulated according to a modulation method such as quadrature amplitude modulation (QAM). The resulting symbols from such a modulation method require additional transmit-side processing. These processed symbols are ultimately amplified by a power amplifier (PA) prior to over-the-air (OTA) transmission. PA amplification mitigates signal impairments such as path loss and receive-side additive noise.

[0028] However, PA amplification introduces additional signal impairments. For example, the input-output PA characteristic has a linear region (where the output power scales linearly with the input power) and a nonlinear region (where the output power saturates with the input power). Thus, modulation symbols of different amplitudes can not be scaled uniformly by the PA. Additionally, the input-output PA characteristic exhibits a memory effect, where the output at a given time is a function of the modulation symbols input at previous times. Thus, the PA output can exhibit a "smearing" phenomenon around a given modulation symbol, where the degree of smearing depends on the memory effect.

[0029] The following discussion of background art is intended to facilitate an understanding of the principles of the present disclosure and is not a recognition or admission that any of the background art is Figures 1 to 24 The principles of the present disclosure are discussed below with respect to various embodiments used to describe the present principles in this patent document. These embodiments are not to be taken in a limiting sense but are merely used to illustrate principles of the present disclosure.

[0030] Embodiments of the present disclosure recognize that the performance of conventional modulation methods can be compromised due to distortion effects introduced by PA amplification, due to the input-output PA characteristic.

[0031] Accordingly, embodiments of the present disclosure provide a framework that supports modulation methods that take into account the input-output PA characteristic. For example, consider the standard 16-QAM constellation. If the four outermost modulation symbols (i.e., the corner symbols) lie in the nonlinear region of the PA characteristic, while the other twelve modulation symbols lie in the linear region of the PA characteristic, then the constellation can be modified by applying a prescaling factor to only the four outermost modulation symbols. This prescaling factor can be chosen such that, at the PA output, all 16 modulation symbols are scaled uniformly.

[0032] Embodiments of the present disclosure provide methods and apparatus that can be used by a network to configure additional modulation methods that take into account the input-output PA characteristic. Some corresponding signaling details of these methods are also discussed in this disclosure, including information elements to be exchanged between a transmitter and a receiver.

[0033] The following detailed description of embodiments of the present disclosure Figures 1-3 Various embodiments are described that implement and use orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency-division multiple access (OFDMA) communication techniques in a wireless communication system. Figures 1-3The description of the drawings does not imply any physical or architectural limitation to the ways in which different embodiments can be implemented. The various embodiments of the disclosure can be implemented in any appropriate layout of communication systems.

[0034] Figure 1 An example wireless network according to embodiments of the disclosure is illustrated. Figure 1 The embodiment of the wireless network illustrated in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of this disclosure.

[0035] As Figure 1 illustrated, the wireless network includes a gNB 101 (e.g., base station BS), a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0036] The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipment devices (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which can be located in a small business; a UE 112, which can be located in an enterprise; a UE 113, which can be a WiFi hotspot; a UE 114, which can be located in a first residence; a UE 115, which can be located in a second residence; and a UE 116, which can be a mobile device, such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 can communicate with each other and with UEs 111-116 using 5G / NR, long term evolution (LTE), long term evolution enhanced (LTE-A), WiMAX, WiFi, or other wireless communication techniques.

[0037] Depending on the network type, the term "base station" or "BS" can refer to any component (or collection of components) configured to provide wireless access to a network, such as a transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G / NR base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wireless-enabled devices. A base station can provide wireless access to a plurality of UEs 115 using one or more wireless communication protocols, such as 5G / NR Third Generation Partnership Project (3GPP) NR, Long-Term Evolution (LTE), LTE-Advanced (LTE-A), High Speed Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For the sake of convenience, the terms "BS" and "TRP" are used interchangeably herein to refer to a component of a network infrastructure that provides wireless access to remote terminals. Further, depending on the network type, the term "user equipment" or "UE" can refer to any component such as a "mobile station," "subscriber station," "remote terminal," "wireless terminal," "receive point," or "user device." For the sake of convenience, the terms "user equipment" and "UE" are used interchangeably herein to refer to a remote wireless device that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or a vending machine).

[0038] Dotted lines show the approximate extents of the coverage areas 120 and 125 as approximately circular for the purposes of illustration and explanation only. It is expressly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, can have other shapes, including irregular shapes, depending on configuration of the gNBs and variations in the wireless environment associated with natural and man-made obstructions.

[0039] As described in more detail below, one or more of the UEs 111-116 include circuitry, programming or a combination thereof, for determining a modulation scheme with an adjusted symbol constellation to pre-compensate for distortion effects of a power amplifier. In certain embodiments, one or more of the gNBs 101-103 include circuitry, programming or a combination thereof to support determining a modulation scheme with an adjusted symbol constellation to pre-compensate for distortion effects of a power amplifier.

[0040] Although Figure 1 One example of a wireless network is illustrated, but Figure 1Various changes can be made. For example, the wireless network could include any number of gNBs and any number of UEs in any suitable arrangement. In addition, a gNB 101 could communicate directly with any number of UEs and provide those UEs access to the network 130 by providing

[0041] Figure 2 An example gNB 102 according to embodiments of the present disclosure is illustrated. Figure 2 The embodiment of the gNB 102 illustrated in Figure 1 The gNBs 101 and 103 of FIG. 1 can have the same or similar configuration. However, gNBs have a variety of configurations and Figure 2 The scope of the present disclosure is not limited to any particular implementation of gNBs.

[0042] As Figure 2 The gNB 102 is illustrated showing an example gNB 102 according to embodiments of the present disclosure.

[0043] The transceivers 210a-210n receive input RF signals, such as signals transmitted by UEs in the network 100, from the antennas 205a-205n. The transceivers 210a-210n down-convert the input RF signals to generate IF or baseband signals. The IF or baseband signals are processed by the receive (RX) processing circuitry in the transceivers 210a-210n and / or by the controller / processor 225 to reproduce the original data modulation on the baseband or IF signals. The controller / processor 225 can further process the baseband signals.

[0044] Transmit (TX) processing circuitry and / or a controller / processor 225 in transceiver 210a-210n receives analog or digital data, such as voice data, web data, e-mail, or interactive video game data, from the controller / processor 225. The TX processing circuitry encodes, multiplexes, and / or digitizes the output baseband data to generate processed baseband or IF signals. The transceiver 210a-210n up-converts the baseband or IF signals to RF signals by frequency modulating the signals using the output from the synthesizer 215. In some embodiments, the transceiver 210a-210n each includes a modulator with adjusted modulation and a PA, which facilitates symbol modulation that accounts for distortion introduced by the PA, as discussed further below. In some embodiments, the transceiver 210a-210n further includes a digital pre-distorter (DPD), which further facilitates symbol modulation that accounts for distortion introduced by the PA, as discussed further below. In other embodiments, the controller / processor 225 can include the functionality of the DPD.

[0045] The controller / processor 225 can include one or more processors or other processing devices to manage the overall operation of the gNB 102. For example, the controller / processor 225 can control the reception of

[0046] The controller / processor 225 can further be capable of executing programs and other processes resident in the memory 230, such as processes for determining a modulation scheme with adjusted symbol constellations to pre-compensate for distortion effects of power amplifiers. The controller / processor 225 can move data into or out of memory 230 as needed by executing processes resident in the memory 230.

[0047] The controller / processor 225 is also connected to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. It can support communication with other gNBs according to any suitable protocol, such as a cellular protocol, an Ethernet protocol, etc. For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G / NR, LTE, or LTE-A), the interface 235 can allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 can allow the gNB 102 to communicate with other gNBs over a wired or wireless local area network, or with a larger network (such as the Internet) through a wired or wireless connection. The interface 235 includes any suitable structure supporting circuits that provide for communication over a wired or wireless connection, such as a transceiver.

[0048] The memory 230 is connected to the controller / processor 225. A portion of the memory 230 can include a RAM, and another portion of the memory 230 can include a flash memory or other ROM.

[0049] Although Figure 2 one example of a gNB 102 is shown, various changes can be made Figure 2 to Figure 2 each component shown. In addition, various components of the gNB 102 can be combined, further subdivided, or omitted and additional components can be added according to particular needs. Figure 2

[0050] Figure 3 An example UE 116 according to embodiments of the present disclosure is shown. Figure 3 The embodiment of the UE 116 shown in Figure 1 UEs 111-115 can have the same or similar configuration. However, UEs come in a wide variety of configurations, and Figure 3 the scope of the present disclosure is not limited to any particular implementation of a UE.

[0051] As Figure 3 shown, the UE 116 includes an antenna 305, a transceiver 310, and a microphone 320. The UE 116 also includes a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, an input 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0052] ​The transceiver 310 receives, from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100. The transceiver 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is processed by the RX processing circuitry in the transceiver 310 and / or the processor 340, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuitry transmits the processed baseband signal to the speaker 330 (such as for voice data) or to the processor 340 (for example, for web browsing data).

[0053] The TX processing circuitry in the transceiver 310 and / or the processor 340 receives analog or digital voice data from the microphone 320 or other output baseband data (such as web data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry encodes, multiplexes, and / or digitizes the output baseband data to generate a processed baseband or IF signal. The transceiver 310 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna 305. In some embodiments, the TX processing circuitry in the transceiver 310 includes a modulator adjusted to facilitate symbol modulation that accounts for distortion introduced by the PA, as discussed further below. In some embodiments, the transceiver 310 further includes DPD that further facilitates symbol modulation that accounts for distortion introduced by the PA, as discussed further below. In other embodiments, the processor 340 can include the functionality of the DPD.

[0054] The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 can control the reception of

[0055] The processor 340 additionally can include a modem subsystem, which can communicate with the modem subsystem of the gNB 102 under direction of the OS 361. The processor 340 can be configured to perform one or more of the processes described herein, such as the process of determining a modulation scheme with an adjusted symbol constellation to pre-compensate for distortion effects of a power amplifier. The processor 340 can move data into or out of memory 360 as

[0056] The processor 340 is also coupled to the input 350 and the display 355, which include, for example, a touchscreen, a keypad, and the like. The operator of the UE 116 can use the input 350 to enter data into the UE 116. The display 355 can be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from web sites.

[0057] The memory 360 is coupled to the processor 340. Part of the memory 360 can include random access memory (RAM), and another part of the memory 360 can include a flash memory or other read-only memory (ROM).

[0058] Although Figure 3 various changes can be made to Figure 3 For example, Figure 3 various components in the can be combined, further subdivided, or omitted and additional components can be added according to particular needs. As a specific example, the processor 340 can be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In another example, the transceiver 310 can include any number of transceivers and signal processing chains, and can be connected to any number of antennas. Further, although Figure 3 the UE 116 is shown as a mobile telephone or smartphone, the UE can be configured to operate as other types of mobile or stationary devices.

[0059] As described above, when preparing digital information bits for transmission in a wireless system (e.g., gNB 102 or UE 116), they are encoded, the encoded bits are modulated to generate symbols, and the symbols are further processed before being amplified by a PA for transmission. The PA amplifies to pre-compensate for path loss and additive noise at the receiver to ensure that the message can be received. However, this comes at the cost of introducing distortion effects inherent to the PA. The PA can introduce non-linear effects and memory effects that affect the modulated symbols input to the PA, resulting in distorted transmitted symbols that can be incorrectly demodulated at the receiving end.

[0060] Figure 4An example input-output PA characteristic 400 according to an embodiment of this disclosure is illustrated. The example PA characteristic 400 can be broadly divided into three regions: region 1 (402) where the input amplitude is between 0 and 0.4, and the PA output scales almost linearly with the input; region 2 (404) where the input amplitude is between 0.4 and 0.6, and the PA output scales almost linearly with the input, although the slope is reduced relative to region 1; and region 3 (406) where the input amplitude is above 0.6, and the PA output scales non-linearly with the input—in fact, for input amplitudes above 0.8, the PA output is effectively saturated. The non-linear distortion in the example PA characteristic 400 motivates the application of modulation methods that take this non-linear distortion into account.

[0061] Figure 5 An example of a modulation symbol constellation according to an embodiment of this disclosure is shown. Figure 5 The three constellations in the text are considered to be associated with... Figure 4 The PA properties are used with PA 400. Additionally, Figure 5 The constellations are mapped to different MCS indices. Assuming all 16 modulation symbols in the rightmost constellation 506 are located in region 1 (402) of PA characteristic 400, the PA will apply uniform scaling to that constellation. If the four outermost symbols in the rightmost constellation 506 are located in region 3 (406) of PA characteristic 400, the PA will not apply uniform scaling to that constellation. Instead, the non-uniform spacing observed in the middle constellation 504 and the leftmost constellation 502 can be considered as pre-scaling of the outermost (and in this case, the middle) modulation symbols before PA amplification. When modulation symbols from these constellations are applied to the corresponding target PA operating point, the constellation of transmitted symbols at the PA output is almost square (e.g., as will be discussed below). Figure 12 The constellation on the right (1250).

[0062] Figure 5 It also emphasizes the PA-aware modifications to the traditional methods used to determine the modulation scheme. For example, Table 5.1.3.1-1 in reference [4] shows that modulation and coding scheme (MCS) indices 10-16 are all mapped to a modulation scheme, namely 16-QAM. Figure 5 This demonstrates that the method can be modified to support different constellations based on the MCS index for a given modulation order, which can compensate for nonlinear distortion. Amplification is achieved using a given PA. Figure 5 Each constellation in the MCS index can produce different output constellations and different spectral efficiencies—even if a code rate is used for MCS index 10-16.

[0063] Figure 6An example method 1000 for a UE operation to support different constellations per MCS index for a given modulation order is shown, in accordance with an embodiment of the present disclosure. At operation 1002, the UE sends its capability information to the BS, which includes its capability to support additional modulation methods other than the legacy modulation methods (e.g., its capability to support modulation methods using adjusted symbol constellations, which can be adjusted from a legacy symbol constellation such as the symbol constellation for 16-QAM). At operation 1004, the UE receives modulation mode configuration information from the BS, which can include information such as the enabling / disabling of the mapping between MCS index and modulation method. At operation 1006, the UE receives a MCS indication message from the BS. The BS can use an existing DCI format for this MCS indication message. The BS can also define a new DCI format for this MCS indication message. In one example, the UE uses this MCS indication message to determine the MCS index. In another example, the UE can autonomously determine the MCS index. At operation 1008, the UE sends modulation symbols to the BS, which can be selected from a constellation corresponding to the MCS index (which can be, for example, an adjusted symbol constellation).

[0064] Figure 7 An example method 1100 for a BS operation to support different constellations per MCS index for a given modulation order is shown, in accordance with an embodiment of the present disclosure. At operation 1102, the BS receives capability information from the UE, which includes the UE's capability to support additional modulation methods other than the legacy modulation methods (e.g., the UE's capability to support modulation methods using adjusted symbol constellations, which can be adjusted from a legacy symbol constellation such as the symbol constellation for 16-QAM). At operation 1104, the BS sends modulation mode configuration information to the UE, which can include information such as the enabling / disabling of the mapping between MCS index and modulation method. At operation 1106, the BS sends a MCS indication message to the UE. The BS can use an existing DCI format for this MCS indication message. The BS can also define a new DCI format for this MCS indication message. In one example, the UE uses this MCS indication message to determine the MCS index. In another example, the UE autonomously determines the MCS index. At operation 1008, the BS receives modulation symbols from the UE, which can be selected from a constellation corresponding to the MCS index (which can be, for example, an adjusted symbol constellation).

[0065] In various embodiments of the present disclosure, a UE can indicate its capability to support additional modulation methods other than traditional modulation methods (e.g., modulation methods that use adjusted symbol constellations that can be adjusted from traditional symbol constellations such as the symbol constellation for 16-QAM). To signal its capability, the UE can use a modified ModulationOrder IE to indicate all modulation methods that the UE can support. One example of the modified ModulationOrder IE used as a UE capability information message is provided below: ModulationOrder ::= BIT STRING {SIZE (NumModMethods)} In this example, “NumModMethods” corresponds to the total number of modulation methods, each value in the bit string corresponds to a modulation method, and the values set to “1” in the bit string correspond to the modulation methods that the UE can support. In some embodiments, the modified ModulationOrder IE can indicate support for adjusted constellations related to MCS index for a given modulation order. In some embodiments, the BS can configure the UE to send the indication of the modulation methods it supports via a MAC CE activation command. In some embodiments, the BS can configure the UE to send the indication of the modulation methods it supports via DCI.

[0066] Figure 8 An example lookup table 800 for facilitating determination of modulation methods based on MCS index is shown in accordance with embodiments of the present disclosure. The example lookup table (or LUT) 800 can be used to support a UE to select different constellations for a given modulation order according to a determined MCS index. In this example, each MCS index maps to a set of 4 “base points”. Each of these base points is located in the first quadrant of the complex plane. These “base points” can be reflected with respect to the real and imaginary axes of the complex plane to obtain all points of a given constellation of size 16. The device can then use this set of 16 points to modulate the coded bits.

[0067] Figure 9 An example input-output PA characteristic 900 for performance evaluation is shown in accordance with embodiments of the present disclosure. The input-output PA characteristic 900 exhibits saturation in the non-linear region, which can be observed in Figure 4 The input-output characteristic 900 also exhibits memory effects because a given input level can map to multiple output levels depending on the input level of the modulation symbol at previous time instances.

[0068] Figure 10 An example plot of the impact of PA saturation and memory effects on traditional modulation methods is shown in accordance with embodiments of the present disclosure. In Figure 10In the example of FIG. 10, the legacy modulation method is 16-QAM. The left constellation 1052 is the legacy 16-QAM constellation. The right constellation 1050 corresponds to the PA output when the constellation 1052 is input to the PA. The impact of PA saturation can be seen in the inward shift of the four outermost constellation points (especially compared to their eight nearest neighbors). The impact of memory effects can be seen in the small “clusters” of points - each of these small “clusters” would collapse to a single point if each input level mapped to a single output level.

[0069] Figure 11 An example system 1150 with a trainable modulator is shown in accordance with embodiments of the present disclosure. It should be appreciated that in some embodiments, the example system 1150 can be implemented in a processor (e.g., the processor 340 of the UE 116). In various embodiments discussed below, the trainable modulator uses an AI-based (or ML-based) training scheme, and for ease of explanation, the trainable modulator is referred to as an AI-based modulator (which implements an AI-based modulation method), but it should be appreciated that any other suitable training scheme can also be used. The trainable modulator of the example system 1150 can be used to design additional modulation methods (e.g., adjusted symbol constellations), such as Figure 5 constellations 502 and 504, which can take into account the input-output PA characteristics.

[0070] For example, the trainable modulator can include a model of the PA input-output characteristics in a framework, and reduce (or preferably minimize) the difference between the constellation of the PA output in that framework and a legacy modulation method (e.g., square 16-QAM). In this example, the trainable encoder 1152 is placed in series with other blocks (i.e., the RC filter 1154, the power scaling block 1156, and the PA 1158). This encoder 1152 can be trained to reduce (and preferably minimize) a loss function 1160 between the PA output and modulation symbols from a target constellation (which can correspond to a legacy symbol constellation scaled by the same amount as the PA gain), such as 16-QAM.

[0071] Figure 12 An example graph of the impact of PA saturation and memory effects on an adjusted modulation method is shown in accordance with embodiments of the present disclosure. In this example, the adjusted modulation method has been designed using an AI architecture. The left constellation 1252 is the AI-designed constellation, which is based on a legacy 16-QAM constellation (e.g., Figure 12 Figure 10 Figure 10 ​​In comparison to the constellation 1050, one can see a reduction in the impact of PA saturation in the four outermost constellation points, which are now roughly on the same level as their eight nearest neighbors. The impact of memory effects can still be observed in the small cluster of points.

[0072] Figure 13 An example wireless transmitter (Tx) architecture 1350 with digital pre-distorter (DPD) is shown in accordance with embodiments of the present disclosure. Figure 13 The example can be implemented in a transceiver of, for example, a gNB 102 or a UE 116. In this example, the adjusted modulator 1352 corresponds to a modulation method that utilizes an adjusted constellation (such as one of the constellations in Figure 5 The modulation method generates a modulation symbol from encoded bits (which are received from a bit generator 1354) and then passes the modulation symbol to the DPD 1356. For this architecture, the DPD 1356 can be trained to reduce (and preferably minimize) the difference between the output of the PA 1358 and an appropriately scaled version of a target constellation 1360 (such as 16-QAM), thereby further reducing the impact of PA saturation and memory effects of the PA. The scaling factor applied to the target constellation (such as 16-QAM) is selected to facilitate convergence of the DPD training process.

[0073] Figure 14 An example SER plot 1450 showing the impact of PA saturation and memory effects on different modulation methods in accordance with embodiments of the present disclosure. The trace 1452 corresponds to a modulation method using a conventional 16-QAM constellation (without applying DPD). As shown by the trace 1454, an adjusted modulation method using an AI-designed constellation (without applying DPD) outperforms this modulation method, illustrating that the AI-designed constellation has reduced the impact of PA saturation. As shown by the trace 1456 (for the conventional 16-QAM constellation) and the trace 1458 (for the AI-designed constellation), applying DPD in conjunction with these two modulation methods reduces the impact of residual memory effects.

[0074] In some embodiments, the modulation method can be determined based on the transmit power of the UE. In the method of these embodiments, the constellation points in a conventional modulation method (such as 16-QAM) can be adjusted according to the transmit power level. The transmit power level can correspond to the power level of the output of the PA of the transmitter or transceiver of the UE, which in turn can correspond to the operating point of the PA.

[0075] In current practice, the PA operating point is typically backed off from the saturation region to maintain PA linearity - i.e., uniform scaling of the (unadjusted) input constellation. However, in the embodiments of the present disclosure provided below, adjusting the constellation points can support a higher PA operating point (e.g., in the saturation region), thereby maintaining PA efficiency while preserving PA linearity (i.e., uniform scaling of the (adjusted) input constellation).

[0076] Figure 15 An example method 1200 for UE operation to support power level based constellation adjustment is shown, in accordance with an embodiment of the present disclosure. At operation 1202, the UE determines a MCS index. In one example, the MCS index can be indicated by the BS. In another example, the UE determines the MCS index autonomously. At operation 1204, the UE checks its transmit power level. At operation 1206, the UE adjusts the constellation used for its modulation method based on its transmit power level. In one example, the UE adjusts the location of the points in the constellation. At operation 1208, the UE can optionally apply a power backoff value in addition to the constellation adjustment in operation 1206. The backoff value can be less than that of a conventional square QAM constellation, as the constellation adjustment has already pre-compensated for PA saturation. In some embodiments, the UE can iteratively perform operations 1204 and 1206 (or 1204-1208) to alternately update the transmit power level and adjust the symbol constellation. At operation 1210, the UE modulates the encoded bits using the adjusted constellation and transmits the corresponding modulation symbols to the BS.

[0077] Figure 16 An example method 1300 for BS operation to support power level based constellation adjustment is shown, in accordance with an embodiment of the present disclosure. At operation 1302, the BS sends a MCS indication to the UE. The BS can use an existing DCI format for the MCS indication message. The BS can also define a new DCI format for the MCS indication message. At operation 1304, the BS optionally receives a constellation adjustment indication from the UE. If the BS receives the constellation adjustment indication from the UE, the indication corresponds to modulation symbols that the BS will receive in a subsequent time slot (facilitating real-time demodulation). In one example, a dedicated / new MAC CE can be used for the indication, or an existing MAC CE can be used for the indication. In another example, the indication can be sent on PUCCH or PUSCH, where a new UCI format can be defined for the indication, or an existing UCI format can be used for the indication. If an existing UCI format is used for the indication, it can be included as part of the UCI and thus reported with CSI feedback, e.g., as a 1-bit indication in a CSI report. At operation 1306, the BS receives modulation symbols from the adjusted constellation from the UE.

[0078] In another example, the BS can pre-determine / configure information related to the switching time to switch to the modulation method based on the adjusted constellation. In this case, operation 1304 can be skipped, and in operation 1306, the BS can receive from the UE the modulation symbols from the adjusted constellation at the pre-determined / configured time.

[0079] In another example, between operation 1304 and operation 1306, the BS can perform operation 1305. In operation 1305, the BS can send an ACK / NACK indication to the UE in response to the received constellation adjustment indication. If the BS sends an ACK, the UE generates the modulation symbols using the adjusted constellation. In operation 1306, the BS receives the modulation symbols from the UE. If the BS sends a NACK, the UE generates the modulation symbols using the unadjusted constellation, and in operation 1306, the BS receives the modulation symbols from the UE. In operation 1305, in another example, the BS can send a configuration message to the UE for the constellation adjustment.

[0080] Figure 17 An example method 1400 for UE operation to support power level based constellation adjustment is shown, according to embodiments of the present disclosure. In operation 1402, the UE receives an MCS indication from the BS. The BS can use an existing DCI format for this MCS indication message, or the BS can define a new DCI format for this MCS indication message. In operation 1404, the UE optionally sends a constellation adjustment indication to the BS. If the UE sends to the BS the constellation adjustment indication, the indication corresponds to the modulation symbols that the BS will receive in the subsequent time slots (facilitating real-time demodulation). In one example, a dedicated / new MAC CE can be used for this indication, or an existing MAC CE can be used for this indication. In another example, this indication can be sent on PUCCH or PUSCH, where a new UCI format can be defined for this indication, or an existing UCI format can be used for this indication. If an existing UCI format is used for this indication, it can be included as part of the UCI and thus reported together with the CSI feedback, e.g., as a 1-bit indication in the CSI report. In operation 1406, the UE sends to the BS the modulation symbols from the adjusted constellation.

[0081] In another example, the BS can pre-determine / configure information related to the switching time to switch to the modulation method based on the adjusted constellation. In this case, operation 1304 can be skipped, and in operation 1306, the BS can receive from the UE the modulation symbols from the adjusted constellation at the pre-determined / configured time.

[0082] In another example, between operation 1404 and operation 1406, the UE can perform operation 1405. In operation 1405, in response to the received constellation adjustment indication, the UE can receive an ACK / NACK indication from the BS. If the UE receives an ACK, the UE generates modulation symbols using the adjusted constellation, and in operation 1406, the UE transmits the modulation symbols to the BS. If the UE receives a NACK, the UE generates modulation symbols using the unadjusted constellation, and in operation 1406, the UE transmits the modulation symbols to the BS. In operation 1405, in another example, the UE can receive a configuration message for constellation adjustment from the BS.

[0083] Figure 18 An example method 1500 for supporting BS operations for UE-initiated fallback to a legacy constellation is shown, according to embodiments of the present disclosure. In operation 1502, the BS transmits an MCS indication to the UE. The BS can use an existing DCI format for this MCS indication message, or the BS can also define a new DCI format for this MCS indication message. In operation 1504, the BS optionally receives a constellation adjustment indication from the UE. In one example, a dedicated / new MAC CE can be used for this indication, or an existing MAC CE can be used for this indication. In another example, this indication can be transmitted on PUCCH or PUSCH, where a new UCI format can be defined for this indication, or an existing UCI format can be used for this indication. If an existing UCI format is used for this indication, it can be included as part of the UCI and thus reported together with CSI feedback, e.g., as a 1-bit indication in a CSI report. In operation 1506, the BS receives modulation symbols from the adjusted constellation from the UE. In operation 1508, the BS receives a constellation fallback indication from the UE, which will be further described below. In operation 1510, the BS receives modulation symbols from the legacy constellation from the UE.

[0084] In another example, the BS can pre-determine / configure information related to a switching time to switch to modulation methods based on the adjusted constellation. In this case, operation 1504 need not be performed, and in operation 1506, the BS can receive modulation symbols from the adjusted constellation from the UE at the pre-determined / configured time.

[0085] In another example, between operation 1504 and operation 1506, the BS can perform operation 1505. In operation 1505, the BS can send an ACK / NACK indication to the UE in response to the received constellation adjustment indication. If the BS sends an ACK, the UE generates the modulation symbols using the adjusted constellation, and in operation 1506, the BS receives these modulation symbols from the UE. If the BS sends a NACK, the UE generates the modulation symbols using the unadjusted constellation, and in operation 1506, the BS receives these modulation symbols from the UE. In operation 1505, in another example, the BS can send a configuration message to the UE for the constellation adjustment.

[0086] Figure 19 An example method 1600 for UE operation to support UE-initiated fallback to a legacy constellation without constellation adjustment is shown, according to embodiments of the present disclosure. In operation 1602, the UE receives an MCS indication from the BS. The BS can use an existing DCI format for this MCS indication message, or the BS can also define a new DCI format for this MCS indication message. In operation 1604, the UE optionally sends a constellation adjustment indication to the BS. In one example, a dedicated / new MAC CE can be used for this indication, or an existing MAC CE can be used for this indication. In another example, this indication can be sent on PUCCH or PUSCH, where a new UCI format can be defined for this indication, or an existing UCI format can be used for this indication. If an existing UCI format is used for this indication, it can be included as part of the UCI and thus reported together with CSI feedback, e.g., as a 1-bit indication in a CSI report. In operation 1606, the UE sends modulation symbols from the adjusted constellation to the BS. In operation 1608, the UE sends a constellation fallback indication to the BS, which will be further described below. In operation 1610, the UE sends modulation symbols from the legacy constellation to the BS.

[0087] In another example, the BS can pre-determine / configure information related to a switching time to switch to a modulation method based on the adjusted constellation. In this case, operation 1604 can be skipped, and in operation 1606, the UE can send modulation symbols from the adjusted constellation to the BS at the pre-determined / configured time.

[0088] In another example, between operation 1604 and operation 1606, the UE can perform operation 1605. In operation 1605, in response to the received constellation adjustment indication, the UE can receive an ACK / NACK indication from the BS. If the UE receives an ACK, the UE generates modulation symbols using the adjusted constellation, and in operation 1606, the UE transmits the modulation symbols to the BS. If the UE receives a NACK, the UE generates modulation symbols using the unadjusted constellation, and in operation 1606, the UE transmits the modulation symbols to the BS. In operation 1605, in another example, the UE can receive a configuration message for constellation adjustment from the BS.

[0089] Figure 20 An example method 1700 for supporting BS operations for BS initiated fallback to legacy constellation is shown, according to embodiments of the present disclosure. In operation 1702, the BS transmits an MCS indication to the UE. The BS can use an existing DCI format for this MCS indication message, or the BS can also define a new DCI format for this MCS indication message. In operation 1704, the BS optionally receives a constellation adjustment indication from the UE. In one example, a dedicated / new MAC CE can be used for this indication, or an existing MAC CE can be used for this indication. In another example, this indication can be transmitted on PUCCH or PUSCH, where a new UCI format can be defined for this indication, or an existing UCI format can be used for this indication. If an existing UCI format is used for this indication, it can be included as part of the UCI and thus reported together with CSI feedback, e.g., as a 1-bit indication in a CSI report. In operation 1706, the BS receives modulation symbols from the adjusted constellation from the UE. In operation 1708, the BS transmits a command to the UE to switch to a legacy constellation. In one example, the BS can configure the UE to switch to a legacy constellation via a PDCCH command, where a new DCI format can be defined and this PDCCH command can be triggered by this new DCI format. In another example, the BS can configure the UE to switch to a legacy constellation via a RRC reconfiguration message. In operation 1710, the BS receives modulation symbols from the legacy constellation from the UE.

[0090] In another example, the BS can pre-determine / configure information related to a switching time to switch to modulation method based on the adjusted constellation. In this case, operation 1704 does not need to be performed, and in operation 1706, the BS can receive modulation symbols from the adjusted constellation from the UE at the pre-determined / configured time.

[0091] In another example, between operation 1704 and operation 1706, the BS can perform operation 1705. In operation 1705, the BS can send an ACK / NACK indication to the UE in response to the received constellation adjustment indication. If the BS sends an ACK, the UE generates the modulation symbols using the adjusted constellation, and in operation 1706, the BS receives the modulation symbols from the UE. If the BS sends a NACK, the UE generates the modulation symbols using the unadjusted constellation, and in operation 1706, the BS receives the modulation symbols from the UE. In operation 1705, in another example, the BS can send a configuration message to the UE for the constellation adjustment.

[0092] Figure 21 An example method 1800 for UE operation to support BS initiated fallback to legacy constellation is shown, according to embodiments of the present disclosure. In operation 1802, the UE receives an MCS indication from the BS. The BS can use an existing DCI format for this MCS indication message, or the BS can also define a new DCI format for this MCS indication message. In operation 1804, the UE (optionally) sends a constellation adjustment indication to the BS. In one example, a dedicated / new MAC CE can be used for this indication, or an existing MAC CE can be used for this indication. In another example, this indication can be sent on PUCCH or PUSCH, where a new UCI format can be defined for this indication, or an existing UCI format can be used for this indication. If an existing UCI format is used for this indication, it can be included as part of the UCI and thus reported together with CSI feedback, e.g., as a 1-bit indication in a CSI report. In operation 1806, the UE sends modulation symbols from the adjusted constellation to the BS. In operation 1808, the UE receives a command from the BS to switch to a legacy constellation. In one example, the BS can configure the UE to switch to a legacy constellation via a PDCCH command, where a new DCI format can be defined and this PDCCH command can be triggered by this new DCI format. In another example, the BS can configure the UE to switch to a legacy constellation via a RRC reconfiguration message. In operation 1810, the UE sends modulation symbols from the legacy constellation to the BS.

[0093] In another example, the BS can pre-determine / configure information related to a switching time to switch to a modulation method based on the adjusted constellation. In this case, operation 1804 does not need to be performed, and in operation 1806, the UE can send modulation symbols from the adjusted constellation to the BS at the pre-determined / configured time.

[0094] In another example, between operation 1804 and operation 1806, the UE can perform operation 1805. In operation 1805, in response to the received constellation adjustment indication, the UE can receive an ACK / NACK indication from the BS. If the UE receives an ACK, the UE generates modulation symbols using the adjusted constellation, and in operation 1806, the UE transmits these modulation symbols to the BS. If the UE receives a NACK, the UE generates modulation symbols using the unadjusted constellation, and in operation 1806, the UE transmits these modulation symbols to the BS. In operation 1805, in another example, the UE can receive a configuration message for constellation adjustment from the BS.

[0095] In one embodiment, a new MAC CE can be defined for the constellation adjustment indication used in the above examples. The MAC CE can be identified by a MAC subheader with a logical channel ID. The MAC CE can have a variable size and include the following fields: Transmit power level: This field indicates the transmit power level of the UE, e.g., measured in dBm. The field can also include a power backoff value that the UE has optionally applied.

[0096] Original constellation: This field indicates the legacy modulation method that the UE has adjusted, e.g., as an index to a table of predefined legacy modulation methods.

[0097] Adjusted points: In one example, this field can include a list of tuples, where each tuple can contain an index of a point in the constellation of a legacy modulation method and a real / imaginary value of the adjustment that the UE applied to the point. In another example, this field can include a list of tuples, where each tuple can contain an index of a point in the constellation of a legacy modulation method and a value of the amplitude / phase adjustment that the UE applied to the point.

[0098] Figure 22 An example format of the new MAC CE 2200 for constellation adjustment indication is shown, according to embodiments of the present disclosure. In this example, the transmit power level, original constellation, and adjusted points fields each have a length of 8 bits.

[0099] In another embodiment, the BS can configure the UE to send a constellation adjustment indication via DCI.

[0100] In one embodiment, a new MAC CE can be defined for the constellation backoff indication used in the above examples. The MAC CE can be identified by a MAC subheader with a logical channel ID. The MAC CE can have a variable size and include the following fields: Constellation backoff: This field indicates the legacy modulation method that the UE is requesting, e.g., as an index to a table of predefined legacy modulation methods.

[0101] Figure 23 An example format of a new MAC CE 2300 for constellation fallback indication is shown, according to embodiments of the present disclosure. In this example, the constellation fallback field has a length of 8 bits.

[0102] In one embodiment, the BS can configure the UE to send the constellation fallback indication via DCI.

[0103] Figure 24 An example process 2400 for symbol modulation that takes into account distortion introduced by a PA in a wireless transmission device is shown, according to various embodiments of the present disclosure. Figure 24 The process 2400 is performed by a wireless device that includes a transceiver and a processor. For convenience, the process 2400 will be described as performed by a UE (e.g., a 5G / NR UE 116), but it is understood that the process 2400 or a corresponding process can be performed by a 5G / NR base station (e.g., a gNB 102) or by any other suitable wireless communication device (e.g., 6G and beyond devices). Figure 24 The process 2400 will be described as performed by a UE (e.g., a 5G / NR UE 116), but it is understood that the process 2400 or a corresponding process can be performed by a 5G / NR base station (e.g., a gNB 102) or by any other suitable wireless communication device (e.g., 6G and beyond devices).

[0104] Beginning at step 2405, the UE sends UE capability information to the BS, the UE capability information indicating adjusted symbol constellations supported by the UE. The adjusted symbol constellations can be adjusted (e.g., from a symbol constellation such as 16-QAM) to pre-compensate for distortion effects of a PA in a transceiver of the UE.

[0105] In some embodiments, the UE can then receive modulation configuration information from the BS (step 2410). The modulation configuration information can indicate a mapping between MCS indices and the adjusted symbol constellations supported by the UE. For example, the modulation configuration information can include information that maps MCS indices to entries in a LUT. Such entries in the LUT can be coordinates in a complex plane that correspond to points of the adjusted symbol constellations, and modulation symbols can be generated according to the coordinates in the selected LUT entry (e.g., the entry mapped to the determined MCS index).

[0106] Next, the UE receives an MCS indication from the BS (step 2415). In some embodiments, the MCS indication can indicate an MCS index to be used by the UE.

[0107] In some embodiments, the UE then determines the MCS index based on the MCS indication (step 2420).

[0108] In some embodiments, the UE next determines a transmit power level (step 2425). The transmit power level can be related to an operating point of the PA in the transceiver of the UE. The transmit power level can be determined based on the MCS indication or the MCS index.

[0109] The UE then determines an adjusted symbol constellation (step 2430). For example, the UE can select the adjusted symbol constellation from a list of adjusted symbol constellations that the UE is capable of supporting. In some embodiments, the UE determines the adjusted symbol constellation based on the MCS index (such as the MCS index determined at step 2420), or based on the MCS index and a mapping between MCS indexes and adjusted symbol constellations that the UE supports (such as provided by the BS at step 2410).

[0110] In some embodiments, at step 2430, the UE can adjust an existing symbol constellation (e.g., a 16-QAM symbol constellation) based on a parameter such as the transmit power level determined at step 2425 - for example, the UE can determine the adjusted symbol constellation to pre-compensate for at least some distortion effects of the PA at the determined transmit power level. In some embodiments, the UE can iteratively update the transmit power (e.g., return to step 2425), and then determine a new adjusted symbol constellation at step 2430.

[0111] At step 2435, the UE can send a constellation adjustment indication to the BS indicating the determined adjusted symbol constellation. For example, if the UE has determined the adjusted symbol constellation by adjusting an existing constellation itself, it can send the constellation adjustment indication to inform the BS of the adjusted symbol constellation. If the UE has not made any adjustments to the symbol constellation itself (e.g., if the UE has selected the adjusted symbol constellation based on the MCS indication sent by the BS), the UE can skip this step.

[0112] The UE then generates modulation symbols from the input bits according to the determined adjusted symbol constellation (step 2440), after which the UE transmits the modulation symbols to the BS (step 2445).

[0113] In some embodiments, the UE can send a constellation fallback indication to the BS, or receive a command from the BS to switch to another symbol constellation (step 2450). This can occur before or after the UE has transmitted the modulation symbols to the BS at step 2445. In either case, the UE then generates modulation symbols according to the symbol constellation corresponding to the constellation fallback indication or the other symbol constellation corresponding to the command (step 2455). The UE then transmits these modulation symbols to the BS at step 2445.

[0114] The flow diagrams depicted above illustrate example methods or processes in accordance with the principles of the disclosure, and various changes could be made to the methods or processes described in the flow diagrams. For example, while shown as a series of steps, various steps could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps can be omitted or replaced by other steps.

[0115] While the present disclosure has been described with an example embodiment, various changes and modifications can be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. None of the description in this application should be read in the limitations of any particular embodiments described. The scope of the patent protection granted by the claims should and will be based on the claims as filed, rather than on any description in the application.

Claims

1. A user equipment (UE), comprising: The transceiver is configured as follows: The UE capability information is sent to the base station (BS), indicating support for an adjusted symbol constellation, wherein the adjusted symbol constellation is adjusted to pre-compensate for distortion effects of the power amplifier (PA) in the transceiver; and Receive modulation and coding scheme (MCS) indication from the BS; and A processor, operably connected to the transceiver and configured to: Based on the MCS indication, the adjusted symbol constellation is determined; and Based on the determined adjusted symbol constellation, modulation symbols are generated from the input bits. The transceiver is further configured to send the modulation symbols to the BS.

2. The UE according to claim 1, in, The transceiver is further configured to receive modulation configuration information from the BS, the modulation configuration information indicating a mapping between the MCS index and the adjusted symbol constellation supported by the UE; The processor is further configured as follows: Based on the MCS indication, determine the MCS index; and The adjusted symbol constellation is determined based on the MCS index and the mapping.

3. The UE according to claim 2, in, The modulation configuration information includes information that maps the MCS index to entries in the lookup table LUT. Wherein, the entries in the LUT are the coordinates of points in the complex plane corresponding to the adjusted symbol constellation, and The processor is further configured to generate the modulation symbol from the input bits based on the coordinates in the LUT entry mapped to the determined MCS index.

4. The UE according to claim 1, wherein, The processor is further configured to: Based on the MCS indication, the transmit power level and the adjusted symbol constellation are determined to pre-compensate at least a portion of the distortion effect of the PA at the transmit power level.

5. The UE according to claim 4, wherein, The transceiver is further configured to: Send the constellation adjustment instruction for the adjusted symbol constellation determined by the instruction to the BS; and After sending the constellation adjustment instruction, the modulation symbol is sent.

6. The UE according to claim 1, in, The transceiver is further configured to: Send constellation backoff instruction to the BS; and Receive a command from the BS to switch to another symbol constellation; and in, The processor is further configured to: The modulation symbol is generated based on the symbol constellation corresponding to the constellation back-off indication; and The modulation symbol is generated based on other symbol constellations corresponding to the command.

7. A base station (BS), comprising: A transceiver is configured to: receive UE capability information from a user equipment (UE), the UE capability information indicating an adjusted symbol constellation supported by the UE, wherein the adjusted symbol constellation is adjusted to pre-compensate for distortion effects of a power amplifier (PA) in the UE's transceiver; and A processor, operably connected to the transceiver and configured to: generate a modulation and coding scheme (MCS) indication based on the UE capability information, The transceiver is further configured as follows: Send the MCS instruction to the UE; and The UE receives modulation symbols corresponding to the adjusted symbol constellation, which corresponds to the MCS indication.

8. The BS according to claim 7, in, The processor is further configured to: generate modulation configuration information, the modulation configuration information indicating the mapping between the MCS index and the adjusted symbol constellation supported by the UE. The transceiver is further configured to send the modulation configuration information to the UE. The MCS index is determined based on the MCS indication. The adjusted symbol constellation of the received modulation symbols corresponds to the MCS index and the mapping. Wherein, the adjusted symbol constellation of the received modulation symbols corresponds to the MCS indication and the transmit power level of the UE, and Wherein, at least a portion of the distortion effect of the PA at the transmit power level determined by the adjusted symbol constellation pre-compensation.

9. The BS according to claim 8, in, The modulation configuration information includes information that maps the MCS index to entries in the lookup table LUT. Wherein, the entries in the LUT are the coordinates of points in the complex plane corresponding to the adjusted symbol constellation, and The received modulation symbols correspond to coordinates in the LUT entries mapped to the determined MCS index.

10. The BS according to claim 9, wherein, The transceiver is further configured to: Receive from the UE a constellation adjustment instruction indicating the adjusted symbol constellation; and After receiving the constellation adjustment instruction, the modulation symbol is received.

11. The BS according to claim 7, wherein, The transceiver is further configured to: Receive constellation backoff instruction from the UE; and Send a command to the UE to switch to another symbol constellation. The received modulation symbols correspond to the symbol constellation corresponding to the constellation back-off indication, and The received modulation symbols correspond to other symbol constellations that correspond to the command.

12. A method for operating a user equipment (UE), comprising: The UE capability information is sent to the base station BS, the UE capability information indicating the adjusted symbol constellation supported by the UE, wherein the adjusted symbol constellation is adjusted to pre-compensate for the distortion effect of the power amplifier PA in the transceiver of the UE; Receive modulation and coding scheme (MCS) indication from the BS; Based on the MCS indication, the adjusted symbol constellation is determined; Based on the determined adjusted symbol constellation, modulation symbols are generated from the input bits; and The modulation symbol is sent to the BS.

13. The method of claim 12, further comprising: The BS receives modulation configuration information indicating the mapping between the MCS index and the adjusted symbol constellation supported by the UE. Based on the MCS indication, determine the MCS index; and The adjusted symbol constellation is determined based on the MCS index and the mapping.

14. The method of claim 13, wherein: The modulation configuration information includes information that maps the MCS index to entries in the lookup table LUT. The entries in the LUT are the coordinates of points in the complex plane corresponding to the adjusted symbol constellation, and The method includes generating the modulation symbol from the input bits based on coordinates mapped to LUT entries in a determined MCS index.

15. The method of claim 12, further comprising: Based on the MCS indication, the transmit power level and the adjusted symbol constellation are determined to pre-compensate at least a portion of the distortion effect of the PA at the determined transmit power level; Send the constellation adjustment instruction for the adjusted symbol constellation as determined by the instruction to the BS; After sending the constellation adjustment instruction, the modulation symbol is sent; Send constellation backoff instruction to the BS; and The modulation symbol is generated based on the symbol constellation corresponding to the constellation backtracking instruction.

Images