Design of Wake-up Signal Waveform

Abstract

A system and method for generating a wake-up signal are provided. The method includes receiving a plurality of input samples, performing subcarrier mapping on the plurality of input samples to map the plurality of input samples to a set of subcarriers to generate a subcarrier mapper output, generating a first orthogonal frequency division multiplexing (OFDM) signal by mapping at least a portion of the subcarrier mapper output to a first frequency band corresponding to a first wake-up signal symbol, generating a second OFDM signal by mapping at least a portion of the subcarrier mapper output to a second frequency band corresponding to a second wake-up signal symbol, and generating a wake-up signal comprising at least a portion of the first OFDM signal representing the first wake-up signal symbol and at least a portion of the second OFDM signal representing the second wake-up signal symbol.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims priority based on U.S. Patent Application No. 63 / 411,292, filed on September 29, 2022, and the entire disclosure thereof is incorporated herein by reference.

[0002] [Technical Field] Devices and methods consistent with embodiments of the present disclosure relate to frequency - shift keying (FSK) waveform generation based on orthogonal frequency - division multiplexing (OFDM).

Background Art

[0003] Low - power wake - up radios (WURs) in related technologies are a type of receiver that can operate at lower power than conventional receivers. A user equipment (UE) may have both a conventional receiver and a low - power wake - up radio. To save power, the conventional receiver may be placed in a low - power consumption state when applicable (e.g., when the UE is in the idle mode or DRX mode). In this state, the conventional receiver may be switched off (i.e., not perform signal reception or transmission), or may be switched to a near - off mode. While the conventional receiver is in this state, the WUR may be in an operating mode and may monitor for a wake - up signal (WUS). If the WUS is detected and the UE is indicated to switch the conventional receiver on, the UE may switch the conventional receiver on and start executing conventional transmission / reception procedures. For example, it may detect the serving cell, acquire system information, or perform random access.

[0004] Two common designs for the waveforms used to generate WUS are on-off keying (OOK) and frequency shift keying (FSK). OOK is adopted in IEEE 802.11ba. In OOK, the waveform includes ON and OFF patterns in the time domain, and specific patterns are used to transmit information. For example, (ON OFF) may be transmitted by the bit "1", or (OFF ON) may be transmitted by the bit "0". In FSK, the frequency of the waveform transmits information. For example, if a pulse is transmitted above or around the frequency f0, the bit "0" is transmitted, and if a pulse is transmitted above or around the frequency f1, the bit "1" is transmitted. Summary of the Invention Problems to be Solved by the Invention

[0005] According to an embodiment, a system and method for generating a frequency shift keying (FSK) waveform based on orthogonal frequency division multiplexing (OFDM) are provided. Means for Solving the Problems

[0006] According to one embodiment, a method for generating a wake-up signal executed by at least one processor is provided. The method includes receiving a plurality of input samples, performing sub-carrier mapping on the plurality of input samples with respect to a set of sub-carriers to generate a sub-carrier mapper output, generating a first orthogonal frequency division multiplexing (OFDM) signal by mapping at least a part of the sub-carrier mapper output to a first frequency band corresponding to a first wake-up signal symbol, generating a second OFDM signal by mapping at least a part of the sub-carrier mapper output to a second frequency band corresponding to a second wake-up signal symbol, and generating a wake-up signal comprising at least a part of the first OFDM signal representing the first wake-up symbol and at least a part of the second OFDM signal representing the second wake-up symbol.

[0007] Mapping at least a part of the sub-carrier mapper output to the first frequency band may include performing a first inverse discrete Fourier transform (IDFT) on the sub-carrier mapper output, and mapping at least a part of the sub-carrier mapper output to the second frequency band may include performing a second IDFT on the sub-carrier mapper output.

[0008] According to one embodiment, there is provided a wake-up signal waveform generator including at least one memory configured to store computer program code, and at least one processor configured to access the at least one memory and operate as instructed by the computer program code. The computer program code includes reception code configured to cause the at least one processor to receive a plurality of input samples, execution code configured to cause the at least one processor to perform sub-carrier mapping on the plurality of input samples with respect to a set of sub-carriers to generate a sub-carrier mapper output, first generation code configured to cause the at least one processor to generate a first orthogonal frequency division multiplexing (OFDM) signal by mapping at least a part of the sub-carrier mapper output to a first frequency band corresponding to a first wake-up signal symbol, second generation code configured to cause the at least one processor to generate a second OFDM signal by mapping at least a part of the sub-carrier mapper output to a second frequency band corresponding to a second wake-up signal symbol, and third generation code configured to cause the at least one processor to generate a wake-up signal including at least a part of the first OFDM signal representing the first wake-up symbol and at least a part of the second OFDM signal representing the second wake-up symbol.

[0009] According to one embodiment, when executed by a processor in a wake-up signal waveform generator, receiving a plurality of input samples, and for the plurality of input samples, performing sub-carrier mapping that maps the plurality of input samples to a set of sub-carriers to generate a sub-carrier mapper output, mapping at least a portion of the sub-carrier mapper output to a first frequency band corresponding to a first wake-up signal symbol to generate a first orthogonal frequency division multiplexing (OFDM) signal, mapping at least a portion of the sub-carrier mapper output to a second frequency band corresponding to a second wake-up signal symbol to generate a second OFDM signal, and generating a wake-up signal comprising at least a portion of the first OFDM signal representing the first wake-up symbol and at least a portion of the second OFDM signal representing the second wake-up symbol. A non-transitory computer-readable medium storing instructions for causing a processor to execute the method is provided.

[0010] Additional aspects will be presented partially in the following description, partially become apparent from the description, or may be realized by the practice of the presented embodiments of the disclosure.

Brief Description of the Drawings

[0011] Features, aspects, and advantages of specific exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings in which like reference numerals represent like elements.

[0012] FIG. 1 illustrates WUS generation using an OFDM transmitter according to one embodiment.

[0013] FIG. 2 illustrates a WUS symbol generated using an OFDM transmitter according to one embodiment.

[0014] FIG. 3 is a diagram of an example of a network device according to various embodiments of the present disclosure.

[0015] FIG. 4 is a schematic diagram of an example of a wireless communication system according to various embodiments of the present disclosure.

[0016] FIG. 5 is a flowchart illustrating a method for generating a WUS according to various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] The following detailed description of the embodiments refers to the accompanying drawings. The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation to the exact forms disclosed. Changes and modifications are possible in light of the foregoing disclosure, or may be obtained from practice of the implementation. Further, one or more features or components of one embodiment may be integrated with or combined with those of other embodiments (or one or more features of other embodiments). Additionally, in the flowcharts and operation descriptions provided below, one or more operations may be omitted, one or more operations may be added, one or more operations may be executed simultaneously (at least in part), and the order of one or more operations may be interchanged.

[0018] It will be apparent that the systems and / or methods described herein may be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual special control hardware or software code used to implement these systems and / or methods is not a limitation of the implementation. For this reason, the operations and behaviors of the systems and / or methods are described herein without reference to specific software code. It is understood that software and hardware may be designed to implement the systems and / or methods based on the description herein.

[0019] Even if a particular combination of features is recited in a claim and / or disclosed in the specification, these combinations are not intended to limit the disclosure of possible implementations. In fact, many of these features may be combined in ways different from those specifically recited in the claims and / or specifically disclosed in the specification. Each of the dependent claims listed below may depend directly on only one claim, but the disclosure of possible implementations includes each dependent claim in combination with all other claims in the claim group.

[0020] None of the elements, acts, or instructions used herein should be construed as important or essential unless explicitly described. Also, as used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." If only one item is intended, the term "one" or a similar term is used. Also, as used herein, the terms "has," "have," "having," "include," "including," etc. are intended to be open-ended terms. Further, the phrase "based on" is intended to mean "at least in part, based on" unless explicitly stated otherwise. Further, expressions such as "at least one of A and B" or "at least one of A or B" are understood to include only A, only B, or both A and B.

[0021] The related art does not suggest a method of generating WUS based on FSK using an OFDM transmitter that may be used for one OFDM symbol to generate a plurality of WUS symbols. In contrast, one or more embodiments provide an OFDM-based FSK waveform generation scheme that enables the use of a conventional 5G NR transmitter for WUS generation. As a result, power savings may be achieved on the UE side, leading to an extended battery life, and a conventional 5G NR transmitter may be used for WUS generation.

[0022] Waveform generation

[0023] In one way, the WUS may be generated using the FSK modulation of the related art. In other ways, the WUS may be generated using an OFDM transmitter as shown in FIG. 1.

[0024] According to one embodiment, a set of M input samples 110 (x0 to x M-1 ) is mapped to a set of M subcarriers using a subcarrier mapping (SM) block 120. The input samples 110 may be symbols of BPSK (Binary Phase Shift Keying) modulation and / or QPSK (Quadrature Phase Shift Keying) modulation. The input samples 110 may be scaled to have different power levels. The input samples 110 may be processed using a frequency domain window before being mapped to the subcarriers. Also, the input samples 110 may go through a phase change operation, for example, to maintain phase continuity.

[0025] The frequency at which the samples 110 are mapped (e.g., a frequency band composed of one or more subcarriers) may correspond to one or more WUS symbols. For example, the OFDM signal generated by mapping the input 110 to the band above or around f0 (band 0) may indicate symbol 0, and the OFDM signal generated by mapping the input to the band above or around f1 (band 1) may indicate symbol 1. f0 and f1 may be the midpoint frequencies in their respective bands. For example, the band may include 12 resource blocks at a subcarrier spacing of 15 kHz corresponding to a bandwidth of 2.160 MHz. Here, a cyclic prefix (CP) and / or a guard interval (GI) (e.g., a guard interval composed of zeros) may be added to the beginning of the inverse discrete Fourier transform (IDFT) output. After the CP / GI addition, the signal may be modulated to the carrier frequency and processed by digital-to-analog conversion before being transmitted.

[0026] In one embodiment of the method, instead of all of the IDFT outputs, a subset of the IDFT outputs may be used to indicate one or more WUS symbols. For example, the IDFT output may be composed of N samples 150 as shown in FIG. 1, and n output samples (e.g., n = 24 and N = 512) may be used to indicate symbol 0 or 1. One example is shown in FIG. 2 and described below.

[0027] The OFDM signal is generated by mapping the input samples 210 to frequency bands (in one embodiment, the input samples 210 are equivalent to the input samples 110). The signal 220 generated using band 0 is d 0 and is represented as, and the signal 230 generated using band 1 is d 1 and is represented as. Each signal may include N samples. As shown in FIG. 2, the sample index is represented as a subscript.

[0028] To transmit symbol 0, n samples of d 0 are selected. To transmit symbol 1, n samples of d 1 are selected. A cyclic prefix or guard interval may be added to the n-point signal. Subsequently, the signal may be modulated and converted to an analog signal.

[0029] To transmit the next symbol, the same set of n samples or another set of n samples may be selected. For example, in FIG. 2, the n samples are consecutive. In one method, the index of the n samples may be calculated as "mod(n×k + of:n×(k + 1)-1+of,N)". Here, "mod" represents the modulo operation, k is the symbol index starting from 0, and "of" is an integer offset between 0 and N (including 0 and N).

[0030] In one method, if all N samples of the IDFT output are used to indicate WUS symbols, a new set of N samples may be generated using a new set of M input samples, and new symbols may be indicated using the new N samples. In another method, the same N samples may be used to transmit the entire WUS. The M input samples mapped to different bands may be different.

[0031] The above may be extended to more than two bands. When the number of bands is K, each set of N samples may be used to indicate log2K bits.

[0032] The example in FIG. 2 includes symbol 230 shown as [0; 0; 0; 1; 1; 0]. When n = 12, the IDFT output samples 220 and 230 used to indicate the symbol may be determined as [d 0 0to d 0 11 ; d 0 12 to d 0 23 ; d 0 24 to d 0 35 ; d 1 0to d 1 11 ; d 1 12 to d 1 24 ; d 0 36 to d 0 47 . Note that when n < N, the symbol duration is smaller than the OFDM symbol duration. One or more symbols may be used to encode information bits. For example, the information bit "0" may be encoded by symbol

[0010] , and the information bit "1" may be encoded by symbol

[0001] .

[0033] A similar approach may be used to generate an on-off keying (OOK) signal. In an OOK signal, symbol 1 may be indicated using a subset of the IDFT output, and symbol 0 may be indicated by no signal. The band used to generate the OFDM signal for OOK may be different from the band for FSK. For example, the band used for OOK may be a combination of band 0 and band 1.

[0034] In another method according to an embodiment, both FSK and OOK may be used to indicate a wake-up signal (WUS). In this method, to represent symbol 1 in the time domain as in OOK, a signal may be generated using band 0 or band 1. Symbol 0 may be represented by no signal. In a wake-up receiver, the first time-domain energy of the received signal may be detected. If the energy exceeds a threshold, the WUS determines the signal to represent symbol 1. And the frequency of the signal may be determined to be f0 or f1 (e.g., by filtering and energy detection). Here, as in FSK, f0 may indicate symbol 0 and f1 may indicate symbol 1. If the energy of the received signal is below the threshold, it is determined to represent symbol 0, and no further frequency-domain analysis is required. Generally, as in this example, symbols may be represented by the time-domain energy and / or frequency components of the signal.

[0035] The WUS may be transmitted on the same channel as other conventional channels. For example, the gNB may allocate 4 MHz out of a 20 MHz channel for the WUS and use the remaining part of the channel for conventional NR channels such as the downlink shared channel. Since the WUS frame may be transmitted in a duty cycle, 4 MHz does not have to be always allocated for the WUS and may be allocated only when the WUS frame is transmitted. The subcarrier spacing (SCS) used to generate the WUS may be different, for example, based on the SCS of the channel on which the WUS is transmitted. As an example, the SCS may be 15 kHz or 30 kHz in frequency range 1 (FR1).

[0036] In one method according to the embodiment, the WUS input sample 210 for the IDFT may be determined based at least on the SCS. When the SCS is 30 kHz, assume that the set of input samples 210 is given by the vector x. When the SCS is 15 kHz, the number of subcarriers used to map the input (assuming the WUS bandwidth remains the same) is doubled. The input in this case, denoted as x’, may be determined by one of the following: (i) upsample x by the ratio of the SCS, i.e., 30 kHz / 15 kHz = 2, x’ = upsample(x,2); (ii) x’ is a repetition of x, for example, x’ = [x x]; (iii) x’ = [x x*] (where “*” represents conjugation).

[0037] The information bits may be composed of a plurality of WUS symbols, i.e., the information bits may be encoded using the WUS symbols. For example, the information bit “0” may be represented by the WUS symbol

[0010] , and the information bit “1” may be represented by the WUS symbol

[0001] . In other examples, “0”: [1 0 1 0] and “1”: [0 1 0 1].

[0038] Moving on to FIG. 3, the methods and processes described herein may be executed on a device 300 that may be adapted to any type of known computer, server, or data processing device. For example, device 300 may comprise a printed circuit board (PCB) having a processor, a personal computer (PC), or a computing device, a minicomputer, a mainframe computer, a microcomputer, a telephone computing device, a wired / wireless computing device (e.g., a smartphone, a personal digital assistant (PDA)), a laptop, a tablet, a smart device, or any other similar functional device.

[0039] In some embodiments, as shown in FIG. 3, device 300 may include a set of components such as a processor 320, a memory 330, a storage component 340, an input component 350, an output component 360, and a communication interface 370.

[0040] Bus 310 may comprise one or more components that enable communication between the set of components of device 300. For example, bus 310 may be a communication bus, a crossover bar, a network, etc. In FIG. 3, bus 310 is shown as a single line, but bus 310 may be implemented using multiple (more than two) connections between the set of components of device 300. The disclosure is not limited in this regard.

[0041] Device 300 may include one or more processors such as processor 320. Processor 320 may be implemented in hardware, firmware, and / or a combination of hardware and software. For example, processor 320 may include a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a general-purpose single-chip or multi-chip processor, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. Also, processor 320 may be implemented as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors with a DSP core, or any other such configuration, such as a combination of computing devices. In some embodiments, certain processes and methods may be performed by circuitry specialized for a given function.

[0042] Processor 320 may control the overall operation of device 300 and / or a set of components of device 300 (e.g., memory 330, storage component 340, input component 350, output component 360, communication interface 370).

[0043] Device 300 may further include a memory 330. In some embodiments, the memory 330 may include a random access memory (RAM), a read only memory (ROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a magnetic memory, an optical memory, and / or other types of dynamic or static storage devices. The memory 330 may store information and / or instructions for use (e.g., execution) by the processor 320.

[0044] The storage component 340 of the device 300 may store information and / or computer-readable instructions and / or code related to the operation and use of the device 300. For example, the storage component 340, together with a corresponding drive, may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optical disk, and / or a solid state disk), a compact disk (CD), a digital versatile disk (DVD), a universal serial bus (USB) flash drive, a PCMCIA (Personal Computer Memory Card International Association) card, a floppy disk, a cartridge, a magnetic tape, and / or other types of non-transitory computer-readable media.

[0045] Device 300 may further include an input component 350. The input component 350 may include one or more components that enable the device 300 to receive information via user input (e.g., a touch screen, a keyboard, a keypad, a mouse, a stylus, a button, a switch, a microphone, a camera, etc.). Alternatively or additionally, the input component 350 may include sensors for measuring information (e.g., a global positioning system (GPS) component, an accelerometer, a gyroscope, an actuator, etc.).

[0046] The output component 360 of the device 300 may include one or more components that may provide output information from the device 300 (e.g., a display, a liquid crystal display (LCD), a light emitting diode (LED), an organic light emitting diode (OLED), a haptic feedback device, a speaker, etc.).

[0047] Device 300 may further include a communication interface 370. The communication interface 370 may include a receiver component, a transmitter component, and / or a transceiver component. The communication interface 370 may enable Device 300 to establish a connection with and / or transfer communications with other devices (e.g., a server, other devices). The communication may be enabled via a wired connection, a wireless connection, or a combination of wired and wireless connections. The communication interface 370 may enable Device 300 to receive information from and / or provide information to other devices. In some embodiments, the communication interface 370 may provide communication with other devices via a network (local area network (LAN), wide area network (WAN), metropolitan area network (MAN), private network, ad hoc network, intranet, Internet, fiber optic-based network, cellular network (e.g., fifth generation (5G) network, long-term evolution (LTE) network, third generation (3G) network, code division multiple access (CDMA) network, etc.), public land mobile network (PLMN), telephone network (e.g., Public Switched Telephone Network (PSTN), etc.), and / or a combination of these or other types of networks). Alternatively or additionally, the communication interface 370 may provide communication with other devices via a device-to-device (D2D) communication link such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi, LTE, 5G, etc. In other embodiments, the communication interface 370 may include an Ethernet interface, an optical interface, a coaxial interface, an infrared interface, a radio frequency (RF) interface, etc.

[0048] Device 300 may execute one or more processes described herein. Device 300 may perform operations based on a processor 320 that executes computer-readable instructions and / or code that may be stored by a non-transitory computer-readable medium such as memory 330 and / or storage component 340. The computer-readable medium may represent a non-transitory memory device. The memory device may include a memory space within a single physical storage device and / or a memory space distributed across multiple physical storage devices. Some embodiments may relate to systems, methods, and / or computer-readable media at any possible level of integration technical detail. Further, one or more of the components described above may be stored on a computer-readable medium and implemented as instructions executable by at least one processor (and / or may include at least one processor). The computer-readable medium may include a computer-readable non-transitory storage medium (or medium) storing computer-readable program instructions for causing the processor to perform operations.

[0049] A computer-readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. The computer-readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital versatile disks (DVDs), memory sticks, floppy disks, punch cards, mechanically encoded devices such as a raised structure in a groove in which instructions are recorded, and any suitable combination thereof. As used herein, a computer-readable storage medium is not to be construed as being a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., an optical pulse passing through an optical fiber cable), or an electrical signal transmitted through a wire.

[0050] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to respective computing / processing devices, or can be downloaded from an external computer or an external storage device via a network such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions for storage in a computer-readable storage medium within each respective computing / processing device.

[0051] The computer-readable program code / instructions for performing the operation may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, configuration data for an integrated circuit, or source code or object code written in any combination of one or more programming languages including object-oriented programming languages such as Smalltalk and C++, and procedural programming languages such as the "C" programming language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer as a stand-alone software package, partially on the user's computer, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (e.g., through the Internet using an Internet service provider). In some embodiments, for example, an electronic circuit including a programmable logic circuit, a field-programmable gate array (FPGA), or a programmable logic array (PLA) may execute the computer-readable program instructions by utilizing the state information of the computer-readable program instructions to personalize the electronic circuit for performing the aspect or operation.

[0052] These computer-readable program instructions may be provided to a processor 320 of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor 320 of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram (one or more blocks). These computer-readable program instructions may be stored in a computer-readable storage medium that, when the instructions are stored in the medium, comprises an article of manufacture including instructions for implementing aspects of the functions / acts specified in the flowchart and / or block diagram (one or more blocks), and may be stored in a computer-readable storage medium such as, but not limited to, a memory 330 that can direct a computer, programmable data processing apparatus, and / or other devices to function in a particular manner.

[0053] The computer-readable program instructions may be loaded onto a computer, other programmable apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions / acts specified in the flowchart and / or block diagram (one or more blocks).

[0054] The computer-readable instructions and / or code may be read from other computer-readable media or from other devices via a communication interface 370 and loaded into the memory 330 and / or the storage component 340. The computer-readable instructions and / or code stored in the memory 330 and / or the storage component 340 may cause the device 300 to perform one or more of the processes described herein when executed by the processor 320.

[0055] Alternatively or in addition, instead of software instructions, or in combination with software instructions, wired circuits may be used to perform one or more of the processes described herein. Thus, the embodiments described herein are not limited to a particular combination of hardware circuits and software.

[0056] The number and arrangement of components shown in FIG. 3 are provided as an example. In fact, additional components, fewer components, different components, or components with different arrangements may be provided compared to those shown in FIG. 3. Further, two or more components shown in FIG. 3 may be implemented within a single component, or a single component shown in FIG. 3 may be implemented as a plurality of distributed components. Additionally or alternatively, the set(s) of components shown in FIG. 3 may perform one or more functions described as being performed by other sets of components shown in FIG. 3.

[0057] FIG. 4 is a diagram showing an example of a wireless communication system according to various embodiments of the present disclosure. The wireless communication system 400 (which may be represented as a wireless wide area network (WWAN)) may include one or more user equipment (UE) 410, one or more base stations 420, at least one transport network 430, and at least one core network 440. The device 300 (FIG. 3) may be integrated into the UE 410 or the base station 420.

[0058] One or more UEs 410 may access at least one core network 440 and / or IP services 450 via a connection to one or more base stations 420 on the RAN domain 424 and through at least one transport network 430. Examples of UEs 410 may include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, Global Positioning System (GPS), multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electric meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similarly functioning devices. Some of the one or more UEs 410 may be represented as Internet-of-Things (IoT) devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). The one or more UEs 410 may be represented as stations, mobile stations, subscriber stations, mobile units, subscriber units, radio units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless terminals, remote terminals, handsets, user agents, mobile agents, clients, or some other appropriate representation.

[0059] One or more base stations 420 may communicate wirelessly with one or more UEs 410 over the RAN domain 424. Each base station of the one or more base stations 420 may provide communication coverage for one or more UEs 410 located within the geographical coverage area of the base station 420. In some embodiments, as shown in FIG. 4, the base station 420 may transmit one or more beamformed signals to one or more UEs 410 in one or more transmission directions. One or more UEs 410 may receive the beamformed signals from the base station 420 in one or more reception directions. Alternatively or in addition, one or more UEs 410 may transmit beamformed signals to the base station 420 in one or more transmission directions. The base station 420 may receive the beamformed signals from one or more UEs 410 in one or more reception directions.

[0060] The one or more base stations 420 may include macro cells (e.g., high-power cellular base stations) and / or small cells (e.g., low-power cellular base stations). Small cells may include femto cells, pico cells, and micro cells. A base station 420 that is a macro cell or a large cell may include an access point (AP), an evolved (or evolved universal terrestrial wireless access network (E-UTRAN)) Node B (eNB), a next-generation Node B (gNB), or any other type of base station known to those skilled in the art, and / or may be referred to as such.

[0061] One or more base stations 420 may be configured to interface (e.g., establish a connection, transfer data, etc.) with at least one core network 440 through at least one transport network 430. In addition to other functions, one or more base stations 420 may perform one or more of the following functions: transfer of data received from one or more UEs 410 (e.g., uplink data) to at least one core network 440 via at least one transport network 430, transfer of data received from at least one core network 440 (e.g., downlink data) to one or more UEs 410 via at least one transport network 430.

[0062] The transport network 430 may transfer data (e.g., uplink data, downlink data) and / or signaling between the RAN domain 424 and the CN domain 444. For example, the transport network 430 may provide one or more backhaul links between one or more base stations 420 and at least one core network 440. The backhaul link may be wired or wireless.

[0063] The core network 440 may be configured to provide one or more services (e.g., enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communications (mMTC), etc.) to one or more UEs 410 connected to the RAN domain 424 via the TN domain 434. Alternatively or in addition, the core network 440 may function as an entry point for IP services 450. The IP services 450 may include the Internet, an intranet, an IP multimedia subsystem (IMS), streaming services (e.g., video, audio, gaming, etc.), and / or other IP services.

[0064] FIG. 5 is a flowchart illustrating a method 500 for generating a wake-up signal according to an embodiment. Specifically, the method includes an operation 510 in which a wake-up signal generator receives a plurality of input samples. In operation 520, subcarrier mapping of the received plurality of input samples maps the plurality of input samples to a set of subcarriers, resulting in a subcarrier mapper output. In operation 530, a first OFDM signal is generated by mapping at least a portion of the subcarrier mapper output (generated in operation 520) to a first frequency band corresponding to a first wake-up signal symbol. In operation 540, a second OFDM signal is generated by mapping at least a portion of the subcarrier mapper output (generated in operation 520) to a second frequency band corresponding to a second wake-up signal symbol. Finally, in operation 550, a wake-up signal is generated that includes at least a portion of the first OFDM signal (generated in operation 530) representing the first wake-up symbol and at least a portion of the second OFDM signal (generated in operation 540) representing the second wake-up signal.

[0065] The flowchart and block diagrams shown illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer-readable media according to various embodiments. Here, each block in the flowchart or block diagram may represent a micro service, module, segment, or portion of instructions that includes one or more executable instructions for implementing a particular logical function. The methods, computer systems, and computer-readable media may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those shown in the figures. In some alternative implementations, the functions shown in the blocks may occur out of the order shown in the figures. For example, two blocks shown in succession may, in fact, be executed simultaneously or substantially simultaneously depending on the functions involved, or the blocks may be executed in the reverse order. Note that each block of the illustrations of the block diagrams and / or flowcharts, and combinations of blocks in the illustrations of the block diagrams and / or flowcharts, can be implemented by a system based on dedicated hardware for performing a particular function or act, or by a combination of dedicated hardware and computer instructions.

Claims

Claim 1 A method for generating a wake-up signal executed by at least one processor, comprising: receiving a plurality of input samples; performing subcarrier mapping on the plurality of input samples by mapping the plurality of input samples to a set of subcarriers to generate a subcarrier mapper output; generating a first orthogonal frequency division multiplexing (OFDM) signal by mapping at least a portion of the subcarrier mapper output to a first frequency band corresponding to a first wake-up signal symbol; generating a second OFDM signal by mapping at least a portion of the subcarrier mapper output to a second frequency band corresponding to a second wake-up signal symbol; generating a wake-up signal comprising at least a portion of the first OFDM signal representing the first wake-up symbol and at least a portion of the second OFDM signal representing the second wake-up symbol; The method comprising. Claim 2 Mapping at least a portion of the subcarrier mapper output to the first frequency band comprises performing a first inverse discrete Fourier transform (IDFT) on the subcarrier mapper output, Mapping at least a portion of the subcarrier mapper output to the second frequency band comprises performing a second IDFT on the subcarrier mapper output, The method according to claim 1. Claim 3 Generating the first OFDM signal further comprises adding at least one of a cyclic prefix (CP) and a guard interval to the beginning of the output of the first IDFT, Generating the second OFDM signal further comprises adding at least one of a cyclic prefix (CP) and a guard interval to the beginning of the output of the second IDFT, The method according to claim 2. Claim 4 modulating the wake-up signal to a carrier frequency; processing the wake-up signal using a digital-to-analog converter; transmitting the modulated analog wake-up signal; The method according to claim 3, further comprising. Claim 5 The method according to claim 1, wherein the plurality of input samples comprises at least one of a symbol of BPSK (Binary Phase Shift Keying) modulation and a symbol of QPSK (Quadrature Phase Shift Keying) modulation.

6. The method according to claim 1, further comprising processing a plurality of input samples using a frequency domain window before performing subcarrier mapping.

7. The method according to claim 6, further comprising performing a phase change operation on the plurality of input samples before performing subcarrier mapping.

8. At least one memory configured to store computer program code, At least one processor accessing the at least one memory and configured to operate under the instruction of the computer program code, Comprising, The computer program code, Receiving code configured to cause at least one processor to receive a plurality of input samples, Execution code configured to cause at least one processor to perform subcarrier mapping on a plurality of input samples to map the plurality of input samples to a set of subcarriers to generate a subcarrier mapper output, First generation code configured to cause at least one processor to generate a first orthogonal frequency division multiplexing (OFDM) signal by mapping at least a part of the subcarrier mapper output to a first frequency band corresponding to a first wake-up signal symbol, Second generation code configured to cause at least one processor to generate a second OFDM signal by mapping at least a part of the subcarrier mapper output to a second frequency band corresponding to a second wake-up signal symbol, Third generation code configured to cause at least one processor to generate a wake-up signal comprising at least a part of the first OFDM signal representing the first wake-up symbol and at least a part of the second OFDM signal representing the second wake-up symbol, A wake-up signal waveform generator including.

9. The first generation code further comprises code configured to cause at least one processor to perform an inverse discrete Fourier transform (IDFT) on at least a part of the sub-carrier mapper output. The second generation code further comprises code configured to cause at least one processor to perform a second IDFT on at least a part of the sub-carrier mapper output. The wake-up signal waveform generator according to claim 8.

10. The first generation code further comprises code configured to cause at least one processor to add at least one of a cyclic prefix (CP) and a guard interval to the beginning of the output of the first IDFT. The second generation code further comprises code configured to cause at least one processor to add at least one of a cyclic prefix (CP) and a guard interval to the beginning of the output of the second IDFT. The wake-up signal waveform generator according to claim 9.

11. Further comprising a transmitter The computer program code Modulation code configured to cause at least one processor to modulate the wake-up signal to a carrier frequency, Conversion code configured to cause at least one processor to convert the wake-up signal from a digital signal to an analog signal, Transmission code configured to cause at least one processor to transmit the modulated analog wake-up signal by a transmitter, Further comprising The wake-up signal waveform generator according to claim 10.

12. The wake-up signal waveform generator according to claim 8, wherein the plurality of input samples comprises at least one of a symbol of BPSK (Binary Phase Shift Keying) modulation and a symbol of QPSK (Quadrature Phase Shift Keying) modulation.

13. The wake-up signal waveform generator according to claim 8, wherein the computer program code further comprises processing code configured to cause at least one processor to process a plurality of input samples using a frequency domain window before performing sub-carrier mapping.

14. The wake-up signal waveform generator according to claim 13, wherein the computer program code further includes phase change code configured to cause at least one processor to perform a phase change operation on a plurality of input samples before performing a sub-carrier mapping.

15. When executed by a processor in a wake-up signal waveform generator, receiving a plurality of input samples; performing a sub-carrier mapping on the plurality of input samples by mapping the plurality of input samples to a set of sub-carriers to generate a sub-carrier mapper output; generating a first orthogonal frequency division multiplexing (OFDM) signal by mapping at least a portion of the sub-carrier mapper output to a first frequency band corresponding to a first wake-up signal symbol; generating a second OFDM signal by mapping at least a portion of the sub-carrier mapper output to a second frequency band corresponding to a second wake-up signal symbol; generating a wake-up signal comprising at least a portion of the first OFDM signal representing the first wake-up symbol and at least a portion of the second OFDM signal representing the second wake-up symbol; A non-transitory computer-readable medium storing instructions for causing a processor to execute a method comprising the above.

16. Mapping at least a portion of the sub-carrier mapper output to the first frequency band comprises performing a first inverse discrete Fourier transform (IDFT) on the sub-carrier mapper output. Mapping at least a portion of the sub-carrier mapper output to the second frequency band comprises performing a second IDFT on the sub-carrier mapper output. The non-transitory computer-readable medium according to claim 15.

17. Generating the first OFDM signal further comprises adding at least one of a cyclic prefix (CP) and a guard interval to the beginning of the output of the first IDFT. Generating the second OFDM signal further comprises adding at least one of a cyclic prefix (CP) and a guard interval to the beginning of the output of the second IDFT. The non-transitory computer-readable medium according to claim 16.

18. The method comprises modulating a wake-up signal to a carrier frequency; processing the wake-up signal using a digital-to-analog converter; transmitting the modulated analog wake-up signal; The non-transitory computer-readable medium according to claim 17, further comprising. **Claim 19** The non-transitory computer-readable medium according to claim 15, wherein the plurality of input samples comprises at least one of a symbol of BPSK (Binary Phase Shift Keying) modulation and a symbol of QPSK (Quadrature Phase Shift Keying) modulation. **Claim 20** The method comprises: processing a plurality of input samples using a frequency domain window before performing subcarrier mapping; performing a phase change operation on the plurality of input samples before performing subcarrier mapping; The non-transitory computer-readable medium according to claim 15, further comprising.

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