Frequency offset calibration methods and apparatuses, and device and medium

Abstract

The present application relates to the field of communications. Disclosed are frequency offset calibration methods and apparatuses, and a device and a medium. A method comprises: generating a frequency offset calibration signal, wherein the frequency offset calibration signal comprises at least two sub-signals used for frequency offset calibration, the at least two sub-signals are each a part of the frequency offset calibration signal, and the at least two sub-signals are the same; and sending the frequency offset calibration signal to a second device. In the method provided in the present application, a receiving end receives a signal and then performs frequency offset calibration on the received signal on the basis of at least two sub-signals used for frequency offset calibration, without needing a large number of computing resources; and the method is simple, and applicable to an ambient IoT device.

Description

Frequency offset calibration method, device, equipment and medium Technical Field

[0001] The present application relates to the field of communications, and in particular to a frequency offset calibration method, apparatus, device, and medium. Background Art

[0002] To conserve power in Ambient Internet of Things (Ambient IoT) devices, simpler, lower-power oscillators are often used instead of crystal oscillators. However, these oscillators often suffer from poor clock and frequency accuracy, causing significant frequency deviation during Ambient IoT operation, impacting subsequent communications within the device. Therefore, frequency deviation calibration is necessary.

[0003] Since the radio frequency and baseband circuits of ambient IoT devices are very simple, it is difficult to use the frequency offset calibration method in related technologies.

[0004] How to design a frequency offset calibration method for Ambient IoT devices is an unresolved problem.

[0005] Summary of the Invention

[0006] The present application provides a method, apparatus, device, and medium for calibrating frequency offset. The technical solution is as follows:

[0007] According to one aspect of the present application, a frequency offset calibration method is provided. The method is performed by a first device, and the method includes:

[0008] generating a frequency offset calibration signal, wherein the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, the at least two sub-signals are respectively parts of the frequency offset calibration signal, and the at least two sub-signals are identical;

[0009] The frequency offset calibration signal is sent to the second device.

[0010] According to one aspect of the present application, a frequency offset calibration method is provided, where the method is performed by a second device and includes:

[0011] A frequency offset calibration signal sent by a first device is received, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, the at least two sub-signals are respectively part of the frequency offset calibration signal, and the at least two sub-signals are identical when sent.

[0012] According to one aspect of the present application, a frequency offset calibration device is provided, the device comprising:

[0013] a generating module, configured to generate a frequency offset calibration signal, wherein the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, the at least two sub-signals are respectively part of the frequency offset calibration signal, and the at least two sub-signals are identical;

[0014] A sending module is used to send the frequency offset calibration signal to the second device.

[0015] According to one aspect of the present application, a frequency offset calibration device is provided, the device comprising:

[0016] The receiving module is used to receive a frequency offset calibration signal sent by the first device, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, where the at least two sub-signals are respectively part of the frequency offset calibration signal, and the at least two sub-signals are the same when sent.

[0017] According to one aspect of the present application, a computer-readable storage medium is provided, in which a computer program is stored. The computer program is configured to be executed by a processor to implement the above-mentioned frequency offset calibration method.

[0018] According to one aspect of the present application, a chip is provided, which includes a programmable logic circuit and / or program instructions. When the chip is running, it is used to implement the above-mentioned frequency offset calibration method.

[0019] According to one aspect of the present application, a computer program product or computer program is provided, wherein the computer program product or computer program includes computer instructions, the computer instructions are stored in a computer-readable storage medium, and a processor reads and executes the computer instructions from the computer-readable storage medium to implement the above-mentioned frequency offset calibration method.

[0020] The technical solutions provided by the embodiments of the present application include at least the following beneficial effects:

[0021] Frequency offset calibration is performed by sending at least two repeated signals. This method does not require a large amount of storage resources or computing resources, nor does it require complex calculations. It can achieve frequency offset calibration and is suitable for devices with simple structures such as Ambient IoT devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] FIG1 shows a schematic diagram of a communication system provided by the related art;

[0024] FIG2 shows a schematic diagram of radio frequency energy harvesting provided by related art;

[0025] FIG3 is a schematic diagram showing a backscatter communication process provided by the related art;

[0026] FIG4 shows a schematic diagram of resistive load modulation provided by the related art;

[0027] FIG5 is a schematic diagram showing an encoding method provided by related art;

[0028] FIG6 shows a schematic structural diagram of a communication system provided by an exemplary embodiment of the present application;

[0029] FIG7 shows a flow chart of a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0030] FIG8 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0031] FIG9 shows a flow chart of a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0032] FIG10 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0033] FIG11 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0034] FIG12 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0035] FIG13 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0036] FIG14 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0037] FIG15 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0038] FIG16 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0039] FIG17 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0040] FIG18 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0041] FIG19 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0042] FIG20 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0043] FIG21 is a schematic diagram showing a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0044] FIG22 shows an overall flow chart of a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0045] FIG23 shows an overall flow chart of a frequency offset calibration method provided by an exemplary embodiment of the present application;

[0046] FIG24 shows a structural block diagram of a frequency offset calibration device provided by some exemplary embodiments of the present application;

[0047] FIG25 shows a structural block diagram of a frequency offset calibration device provided by some exemplary embodiments of the present application;

[0048] FIG26 shows a schematic structural diagram of a wireless communication device provided by some exemplary embodiments of the present application. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings. Exemplary embodiments will be described in detail herein, with examples shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are merely examples of devices and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0050] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0051] It should be understood that although the terms first, second, third, etc. may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0052] Generally, unless otherwise expressly defined herein, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field. Unless expressly stated otherwise, all references to "an element, device, component, device, step, etc." are to be interpreted openly as referring to at least one instance of the element, device, component, device, step, etc. Unless expressly stated otherwise, the steps of any method disclosed herein do not have to be performed in the exact order disclosed.

[0053] The terminal devices involved in the embodiments of the present application can be active devices, which refer to devices that have their own power supply and can actively generate and transmit signals, such as mobile phones, computers, smart watches, smart bracelets, etc.; they can also be passive devices, which refer to devices that do not require power supply or can work by receiving energy from other devices, which can be called zero-power devices, zero-power terminals, low-power devices, low-power terminals, etc.; they can also be devices that obtain energy from the environment, which can be called ambient energy Internet of Things devices; they can also be devices deployed at fixed locations, which can be called zero-power sites, low-power sites, etc., or they can be terminals with low-power wake-up receivers (Low Power Wake-Up Receiver, LP-WUR) in cellular systems, or they can be STAs with wake-up receivers (Wake-Up Receiver, WUR) in WiFi systems.

[0054] FIG1 shows a schematic diagram of a communication system 100 provided by the related art. The communication system 100 includes a network device 120 and a zero-power device 140 .

[0055] The network device 120 is used to send wireless power supply signals, downlink communication signals and receive backscatter signals from the zero-power device 140 to the zero-power device 140. The zero-power device 140 is also called an Ambient IoT device or an AMP device, and includes an energy collection module 141, a backscatter communication module 142 and a low-power computing module 143. The energy collection module 141 can collect energy carried by radio waves (wireless signals) in space, and is used to drive the low-power computing module 143 of the zero-power device 140 and realize backscatter communication. After the zero-power device 140 obtains energy, it can receive control signaling from the network device 120 and send data to the network device 120 based on the backscattering method according to the control signaling. The data sent can come from the data stored in the zero-power device 140 itself (such as an identity or pre-written information, such as the production date, brand, manufacturer, etc. of the product).

[0056] Zero-power device 140 may also include a sensor module 144 and a memory 145. Sensor module 144 may include various sensors, and zero-power device 140 may report data collected by these sensors based on a zero-power mechanism. Memory 145 is used to store basic information (such as item identification) or obtain sensor data such as ambient temperature and humidity.

[0057] The zero-power device 140 itself does not require a battery, and at the same time, the low-power computing module 143 can perform simple signal demodulation, decoding or encoding, modulation and other simple calculation tasks. Therefore, the zero-power module only requires a very simple hardware design, making the zero-power device 140 very low in cost and small in size.

[0058] The network device 120 includes but is not limited to: cellular network devices, such as 5G / 6G network devices, base station devices; WiFi / WLAN network devices, such as access points (APs), routers, mobile access points, etc., and the mobile access point is, for example, a mobile phone.

[0059] The zero-power device 140 includes but is not limited to: handheld devices, wearable devices, vehicle-mounted devices and Internet of Things devices, etc. The zero-power device 140 can be at least one of a mobile phone, a tablet computer, an e-book reader, a laptop computer, a desktop computer, a television, a game console, an augmented reality (AR) terminal, a virtual reality (VR) terminal and a mixed reality (MR) terminal, a wearable device, a handle, an electronic tag and a controller, etc.

[0060] It should be noted that a zero-power device may also be referred to as at least one of the following: an ultra-low-power device, a low-power device, a passive IoT device, or an ambient power enabled IoT (Ambient IoT / A-IoT) device. The embodiments of this application only use zero-power devices as examples for illustration, but are not limited thereto. Optionally, the first device and / or the second device in the embodiments of this application may be implemented by the aforementioned zero-power devices, or may be implemented by devices other than the aforementioned zero-power devices.

[0061] The communication technology implemented by zero-power devices can be called zero-power communication technology, or ultra-low-power communication technology, or low-power communication technology, or ambient energy Internet of Things technology, or passive Internet of Things technology, or zero-power Internet of Things technology.

[0062] Next, the key technologies of zero-power communication are introduced:

[0063] Radio Frequency Power Harvesting

[0064] Figure 2 shows a schematic diagram of RF energy harvesting provided by related technologies. RF energy harvesting is based on the principle of electromagnetic induction, using a radio frequency (RF) module to conduct electromagnetic induction and maintain a parallel relationship with a capacitor C and a load resistor R. L By connecting to the power supply, the energy required to operate zero-power devices can be collected from electromagnetic waves in space, such as for driving low-power demodulation modules, modulation modules, sensors, and memory reading. Therefore, zero-power devices do not require traditional batteries.

[0065] Back scattering communication

[0066] Figure 3 shows a schematic diagram of the backscatter communication process provided by related art. A zero-power device 140 receives a wireless signal carrier 131 transmitted by a transmitter (TX) module 121 of a network device 120 using an amplifier (AMP) 122. It modulates the wireless signal carrier 131, loads the information to be transmitted using a logic processing module 147, and harvests radio frequency energy using an energy harvesting module 141. Zero-power device 140 radiates the modulated reflected signal 132 using an antenna 146. This information transmission process is called backscatter communication. A receiver (RX) module 123 of the network device 120 receives the modulated reflected signal 132 using a low-noise amplifier (LNA) 124. Backscatter and load modulation are closely related. Load modulation achieves this by adjusting and controlling the circuit parameters of the oscillator circuit of the zero-power device 140 according to the data stream's rhythm, causing parameters such as the electronic tag's impedance to change accordingly.

[0067] Load modulation technology mainly includes resistance load modulation and capacitance load modulation. Figure 4 shows a schematic diagram of resistance load modulation provided by related technology. In resistance load modulation, the load resistor R L The third resistor R3 is connected in parallel, and the switch S based on the binary code control is turned on or off. The on and off of the third resistor R3 will cause the voltage on the circuit to change. The load resistor R L Maintaining a parallel connection relationship with the first capacitor C1, the load resistor R LThe first inductor L1 is connected in series with the second resistor R2, and the second resistor R2 is connected in series with the first inductor L1. The first inductor L1 is coupled to the second inductor L2, and the second inductor L2 is connected in series with the second capacitor C2. Amplitude Shift Keying (ASK) can be implemented, that is, the modulation and transmission of the signal is achieved by adjusting the amplitude of the backscattered signal of the zero-power device. Similarly, in capacitive load modulation, the resonant frequency of the circuit can be changed by turning the capacitor on and off, and frequency shift keying (FSK) can be implemented, that is, the modulation and transmission of the signal is achieved by adjusting the operating frequency of the backscattered signal of the zero-power device.

[0068] Zero-power devices use load modulation to modulate incoming signals, enabling backscatter communication. These devices offer significant advantages: they don't actively transmit signals, eliminating the need for complex RF links like power amplifiers (PAs) and RF filters. They don't actively generate high-frequency signals, eliminating the need for high-frequency crystal oscillators. Furthermore, backscatter communication allows signal transmission without consuming the device's own energy.

[0069] Extremely low power active transmission technology;

[0070] Zero-power devices can also use ultra-low-power active transmission technology. Unlike backscattering, when using ultra-low-power active transmission technology for data transmission, the device uses a relatively simple and low-power oscillator to generate the RF carrier, and then modulates the information to be transmitted onto the RF carrier. Based on current research, the power consumption of ultra-low-power active transmitters can be as low as hundreds of microwatts, thus achieving ultra-low-power data transmission.

[0071] Next, the encoding method of zero-power communication is introduced:

[0072] FIG5 is a schematic diagram of an encoding method provided by related art. The data transmitted by the electronic tag can use different forms of codes to represent binary "1" and "0". Wireless radio frequency identification systems generally use one of the following encoding methods: Not Return to Zero (NRZ) encoding, Manchester encoding, Unipolar Return to Zero (URZ) encoding, Differential Binary Phase (DBP) encoding, Miller encoding, and differential encoding. That is, different pulse signals can be used to represent 0 and 1.

[0073] ·NRZ encoding; Inverse non-return-to-zero encoding uses a high level to represent a binary "1" and a low level to represent a binary "0". Figure 5 shows a level diagram of encoding binary data: 101100101001011 using the NRZ method.

[0074] Manchester encoding: Manchester encoding is also known as split-phase coding. In Manchester encoding, a binary value is represented by a voltage level change (rising or falling) during half a bit period within the bit length. A negative transition during half a bit period represents a binary "1," and a positive transition during half a bit period represents a binary "0." Data transmission errors occur when multiple tags simultaneously transmit data bits with different values, causing the received rising and falling edges to cancel each other, resulting in an uninterrupted carrier signal throughout the entire bit length. Manchester encoding makes it impossible to have an unchanging state within the bit length. The reader can use this error to determine the specific location of the collision. Manchester encoding facilitates data transmission error detection and is commonly used for data transmission from tags to readers when using carrier load modulation or backscatter modulation. Figure 5 shows a schematic diagram of the voltage levels for binary data 101100101001011 encoded using the Manchester method.

[0075] ·URZ encoding; unipolar return-to-zero encoding: a high level in the first half of the bit period represents a binary "1", while a low level signal that lasts throughout the entire bit period represents a binary "1". Figure 5 shows a level diagram of encoding binary data: 101100101001011 using the URZ method.

[0076] DBP encoding: Differential biphase encoding uses any edge within half a bit period to represent a binary "0," while the absence of an edge represents a binary "1." Furthermore, the voltage level is inverted at the beginning of each bit period. This makes the bit beat easier for the receiver to reconstruct. Figure 5 shows the voltage levels of the binary data 101100101001011 encoded using the DBP method.

[0077] Miller coding: In Miller coding, any edge within half a bit period represents a binary "1," while a constant level throughout the next bit period represents a binary "0." The level transition at the beginning of a bit period makes it easier for the receiver to reconstruct the bit beat. Figure 5 shows the level diagram of the binary data 101100101001011 encoded using the Miller method.

[0078] Differential encoding: In differential encoding, each transmitted binary "1" causes a change in the signal level, while for a binary "0" the signal level remains unchanged.

[0079] Next, we will introduce the classification of zero-power devices:

[0080] Based on the energy source and usage of zero-power devices, zero-power devices can be divided into the following types:

[0081] Passive zero-power devices;

[0082] Zero-power devices do not require internal batteries. When they approach a network device, they are within the near field generated by the network device's antenna radiation. For example, the network device is a reader / writer in a radio frequency identification (RFID) system. Therefore, the zero-power device's antenna generates an induced current through electromagnetic induction, which drives the device's low-power chip circuitry. This enables tasks such as demodulating forward link signals and modulating reverse link signals. For backscatter links, the zero-power device can use backscatter or extremely low-power active transmission to transmit signals. Passive zero-power devices do not require internal batteries for either the forward or reverse link, making them truly zero-power devices. Passive zero-power devices do not require batteries, and their RF and baseband circuits are very simple. For example, they do not require components such as LNAs, PAs, crystal oscillators, and analog-to-digital converters (ADCs). They offer numerous advantages, including small size, light weight, very low price, and a long service life.

[0083] Semi-passive zero-power device;

[0084] Semi-passive zero-power devices lack conventional batteries. Instead, they use a radio frequency energy harvesting module to harvest radio wave energy and store it in an energy storage unit, typically a capacitor. This energy is then used to power the device's low-power chip circuitry, enabling tasks such as demodulating forward link signals and modulating backward link signals. For backscatter links, the device can transmit signals using either backscatter or extremely low-power active transmission.

[0085] Semi-passive zero-power devices require no internal batteries for either the forward or reverse link. Instead, the energy stored in the capacitors is harvested by the radio energy harvesting module, making them truly zero-power devices. They inherit many of the advantages of passive zero-power devices, including small size, light weight, very low price, and long service life.

[0086] Active zero-power devices;

[0087] Zero-power devices used in some scenarios can also be active zero-power devices, which can have built-in batteries. The battery is used to drive the low-power chip circuit of the zero-power device. This enables tasks such as demodulating forward link signals and modulating reverse link signals. However, for backscatter links, zero-power devices can use backscatter or extremely low-power active transmission to transmit signals. Therefore, the zero-power of active zero-power devices is mainly reflected in the fact that reverse link signal transmission does not consume the zero-power device's own power, but instead uses backscatter. In active zero-power devices, the built-in battery powers the RFID chip, increasing the tag's read and write distance and improving communication reliability. Therefore, they are used in scenarios with relatively high requirements for communication distance and read latency.

[0088] Next, we will introduce the classification of zero-power devices based on transmitter type:

[0089] (1) Zero-power devices based on backscattering;

[0090] These zero-power devices use backscattering, as described above, for uplink data transmission. They lack active transmitters, only backscattering transmitters. Therefore, when these zero-power devices transmit uplink data, they require network equipment to provide a carrier. These zero-power devices use backscattering based on the carrier to achieve uplink data transmission.

[0091] (2) Zero-power devices based on active transmitters;

[0092] These zero-power devices use active transmitters with active transmission capabilities for uplink data transmission. Therefore, when sending uplink data, these zero-power devices can use their own active transmitters to send uplink data without the need for network equipment to provide a carrier. Examples of active transmitters suitable for zero-power devices include ultra-low-power ASK transmitters and ultra-low-power FSK transmitters. Based on current implementations, these transmitters can reduce overall power consumption to 400-600 microwatts when transmitting a 100-microwatt signal.

[0093] (3) Zero-power devices with both backscatter and active transmitter capabilities;

[0094] These zero-power devices can support both backscatter and active transmitters. They can determine whether to use backscatter or active transmitters based on different situations (such as varying battery levels, available ambient energy), or based on network device scheduling.

[0095] Next, let’s introduce the cellular Internet of Things:

[0096] The cellular Internet of Things (IoT) is booming. The 3rd Generation Partnership Project (3GPP) has standardized IoT technologies such as Narrow Band-Internet of Things (NB-IoT), Machine-Type Communications (MTC), and RedCap. However, IoT communication needs in many scenarios remain unmet. For example:

[0097] Harsh communication environment;

[0098] Certain IoT scenarios may encounter extreme environments such as high temperature, extremely low temperature, high humidity, high voltage, high radiation, or high-speed movement. Examples include ultra-high voltage substations, high-speed train track monitoring, environmental monitoring in high-altitude cold regions, and industrial production lines. In these scenarios, IoT devices will not function due to the operating environment limitations of conventional power supplies. Furthermore, extreme operating environments are not conducive to IoT device maintenance, such as battery replacement.

[0099] ·Requirement for extremely small terminal form factor;

[0100] Certain IoT communication scenarios, such as food traceability, commodity distribution, and smart wearables, require terminals to be extremely small for ease of use. For example, IoT terminals used for commodity management in the distribution process often use electronic tags, which are embedded in the product packaging in a very compact form factor. Another example is lightweight wearable IoT terminals that can meet user needs while improving the user experience.

[0101] Extremely low-cost IoT communication requirements;

[0102] Many IoT communication scenarios require IoT terminal devices to be sufficiently low-cost to enhance their competitiveness compared to alternative technologies. For example, in logistics or warehousing scenarios, IoT terminal devices can be attached to each item to facilitate the management of large quantities of circulating items. Communication between the IoT terminal device and the logistics network enables precise management of the entire logistics process and lifecycle. These scenarios require IoT terminal devices to be sufficiently competitively priced.

[0103] Therefore, in order to cover these unmet IoT communication needs, cellular IoT also needs to develop ultra-low-cost, extremely small-size, battery-free / maintenance-free IoT, and zero-power IoT can just meet these needs.

[0104] Zero-power IoT, also known as Ambient IoT or passive IoT, refers to IoT devices that use various environmental energies, such as radio frequency energy, light energy, solar energy, thermal energy, and mechanical energy, to power themselves. These devices can have no energy storage capacity or very limited energy storage capacity (such as using capacitors with a capacity of tens of microfarads). Compared to existing IoT devices, Ambient IoT devices offer many advantages, including no conventional batteries, no maintenance, small size, low complexity, low cost, and a long lifespan.

[0105] Zero-power IoT can be used in at least four scenarios:

[0106] (1) Object recognition, such as logistics, production line product management, and supply chain management;

[0107] (2) Environmental monitoring, such as temperature, humidity, and harmful gas monitoring of the working environment and natural environment;

[0108] (3) Positioning, such as indoor positioning, intelligent object search, and production line item positioning;

[0109] (4) Intelligent control, such as intelligent control of various electrical appliances in smart homes (turning on and off air conditioners, adjusting temperature), and intelligent control of various facilities in agricultural greenhouses (automatic irrigation and fertilization).

[0110] Ambient IoT devices based on ambient energy:

[0111] In NR and Wi-Fi systems, the battery-free and low-cost nature of devices enables low-cost, large-scale deployment and maintenance-free IoT devices. Current standards are exploring how to support ambient energy-based IoT devices in NR and Wi-Fi systems. These devices, known as ambient IoT (AMP IoT) devices, operate from energy harvested from ambient sources such as wireless signals, solar energy, and thermal energy. These devices are similar to passive or semi-passive devices in zero-power communications.

[0112] A research project on Ambient IoT devices has been carried out in the 3GPP RAN. Ambient IoT devices are roughly divided into three types: Device A, Device B, and Device C, each with corresponding complexity and communication capabilities.

[0113] Device A: does not have energy storage capabilities and cannot transmit independent signals, i.e., it uses backscatter transmission;

[0114] Device B: It has energy storage capabilities but cannot transmit independent signals. Instead, it uses backscattering transmission and can use the stored energy to amplify the backscattered signal.

[0115] Device C: has energy storage capabilities and can send independent signals, that is, has active transmission capabilities.

[0116] Device A has the lowest complexity and power consumption, reaching as low as 1μW. However, its communication range is limited, typically only a few meters. Device A requires a carrier signal from a network device for backscattering transmission. Device C typically has a large capacitor to store energy from the environment, consumes several hundred μW, can support active signal transmission, and has a longer communication range. Because Device C can perform active transmission, it does not require a carrier signal from a network device. Device B's complexity and power consumption are between those of Device A and Device C.

[0117] In addition, zero-power terminals can also support various types of environmental energy harvesting, such as radio frequency, solar energy, thermal energy, mechanical energy, etc. Among them, zero-power terminals based on radio frequency energy harvesting may require the network to provide radio frequency power signals.

[0118] FIG6 shows a schematic diagram of the structure of a communication system provided by an exemplary embodiment of the present application. The communication system includes: a network device 120 and a terminal device 140 .

[0119] Network device 120 may be an access network device in a communication system, such as a base station. Terminal device 140 may be the aforementioned Ambient IoT device. Network device 120 and terminal device 140 transmit data via signals. The signal transmitted from terminal device 140 to network device 120 is referred to as an uplink signal; the signal transmitted from network device 120 to terminal device 140 is referred to as a downlink signal. In this application, the uplink signal and / or the downlink signal may include a frequency offset calibration signal; alternatively, the uplink signal and / or the downlink signal may include at least two sub-signals used for frequency offset calibration.

[0120] It should be noted that FIG6 exemplarily shows a network device and a terminal device. Optionally, the communication system may include multiple network devices and each network device may include a different number of terminal devices within its coverage area. This embodiment of the present application does not limit this. The terminal device 140 may be an Ambient IoT device.

[0121] FIG7 shows a flowchart of a frequency offset calibration method provided by an exemplary embodiment of the present application. The method is performed by a first device, which may be the network device or terminal device shown in FIG6 . The method includes:

[0122] Step 210: Generate a frequency offset calibration signal, where the frequency offset calibration signal includes at least two sub-signals used for frequency offset calibration. The at least two sub-signals are respectively part of the frequency offset calibration signal, and at least the two sub-signals are identical.

[0123] In some embodiments, at least two sub-signals are identical, including at least one of: identical waveform; identical data; identical length; identical phase; identical sequences used to generate the at least two sub-signals; and identical formulas used to generate the at least two sub-signals.

[0124] In some embodiments, at least two sub-signals have the same waveform, in other words, at least two sub-signals have the same data, or the sequences used to generate the at least two sub-signals are the same, or the formulas used to generate the at least two sub-signals are the same.

[0125] In some embodiments, since the at least two sub-signals are identical, the lengths of the at least two sub-signals are identical, that is, the phases of the at least two sub-signals are identical.

[0126] In some embodiments, the at least two sub-signals include a first sub-signal and a second sub-signal; the first sub-signal and the second sub-signal are two continuous parts of the frequency deviation calibration signal; or, the first sub-signal and the second sub-signal are two partially overlapping parts of the frequency deviation calibration signal. As shown in FIG8 , the frequency deviation calibration signal 10 includes at least two sub-signals, and the sub-signals include a first sub-signal 11 and a second sub-signal 12. Schematic diagram (1) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two continuous parts of the frequency deviation calibration signal 10; schematic diagram (2) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two partially overlapping parts of the frequency deviation calibration signal 10.

[0127] In some embodiments, at least two sub-signals use at least one of an OFDM (Orthogonal Frequency-Division Multiplexing) waveform, a hybrid waveform of an OFDM waveform and an OOK (On Off Keying) waveform, a triangle waveform, a square waveform, and a pulse waveform.

[0128] In some embodiments, the subcarrier spacing is at least one of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, 480kHz, 312.5kHz, and 31.25kHz. It should be noted that the subcarrier spacing can also be any value other than the above subcarrier spacing, which is not listed one by one in the embodiments of the present application. Optionally, subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, and 480kHz can be compatible with NR systems; subcarrier spacings of 312.5kHz and 31.25kHz can be compatible with WIFI systems.

[0129] In some embodiments, the frequency offset calibration signal is a periodic signal. One period of the frequency offset calibration signal is the period of a minimum sub-signal that repeatedly appears in the frequency offset calibration signal; or, one period of the frequency offset calibration signal is the time domain length occupied by a minimum sub-signal that repeatedly appears in the frequency offset calibration signal. Each of the at least two sub-signals includes at least one minimum sub-signal.

[0130] In some embodiments, the duration of each of the at least two sub-signals in the time domain is not less than one time domain unit, or the duration of each sub-signal in the time domain is less than one time domain unit. Optionally, when the duration of each sub-signal in the time domain is not less than one time domain unit, the duration of each sub-signal in the time domain is an integer multiple of one time domain unit, or the duration of each sub-signal in the time domain is not an integer multiple of one time domain unit.

[0131] The time domain unit is at least one of a frame, a subframe, a time slot, or a symbol. Optionally, the time length of a frame is defined as 10ms; a frame includes 10 subframes, and the time length of a subframe is 1ms; a subframe includes i time slots, i is a positive integer, and the value of i is related to the subcarrier spacing. The larger the subcarrier spacing, the shorter the actual time length of a time slot; a time slot includes 14 symbols, and the symbol can be an OFDM symbol. It should be noted that the time length definition of a frame can also be other time lengths, such as 15ms, 20ms, etc., and the embodiments of the present application are not limited to this.

[0132] Since the frequency offset calibration signal is a periodic signal, one time domain unit includes multiple periods of the frequency offset calibration signal; or, one time domain unit includes one period of the frequency offset calibration signal.

[0133] In some embodiments, each sub-signal of at least two sub-signals occupies multiple time domain units in the time domain; or, occupies one time domain unit in the time domain; or, the duration occupied in the time domain is not a positive integer multiple of a time domain unit, or, the duration occupied in the time domain is less than one time domain unit.

[0134] Exemplarily, one time domain unit is one symbol. Each of the at least two sub-signals occupies 2 symbols in the time domain; or, occupies 1 symbol in the time domain; or, occupies 2.5 symbols in the time domain; or, occupies 0.5 symbols in the time domain.

[0135] In some embodiments, because a time domain unit includes one or more cycles of the frequency offset calibration signal, each of the at least two sub-signals includes, in the time domain, one or more cycles of the frequency offset calibration signal, or a portion of one cycle, or a non-integer multiple of one cycle. For example, each sub-signal includes, in the time domain, one cycle, two cycles, 0.5 cycles, or 2.5 cycles of the frequency offset calibration signal.

[0136] In some embodiments, the interval between the time domain starting positions of each sub-signal in the at least two sub-signals is a positive integer multiple of a period, which is the period of the frequency offset calibration signal.

[0137] In some embodiments, the time domain starting position of each of the at least two sub-signals is spaced apart by less than one time domain unit. For example, a time domain unit is one symbol. As shown in schematic diagram (1) of FIG8 , the first sub-signal 11 and the second sub-signal 12 occupy one symbol, and the time domain starting positions of the first sub-signal 11 and the second sub-signal 12 are spaced apart by half a symbol, i.e., half a time domain unit.

[0138] Step 220: Send a frequency offset calibration signal to the second device.

[0139] Frequency deviation, also known as carrier frequency offset (CFO), can occur due to at least one of the following: a clock difference between the transmitter and receiver, caused by a mismatch in the oscillators; or Doppler shift during signal transmission.

[0140] In some embodiments, in order to obtain the frequency offset between the first device and the second device for frequency offset calibration, the first device sends a frequency offset calibration signal to the second device, and the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, and the at least two sub-signals are respectively part of the frequency offset calibration signal, and at least the two sub-signals are the same.

[0141] In summary, the method provided in the embodiment of the present application performs frequency offset calibration by sending a frequency offset calibration signal. The frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, and the at least two sub-signals here are the same. This method does not require a large amount of storage resources or computing resources, nor does it require complex calculations to achieve frequency offset calibration. It is suitable for devices with simple structures such as Ambient IoT devices.

[0142] FIG9 shows a flowchart of a frequency offset calibration method provided by an exemplary embodiment of the present application. The method is performed by a second device, which may be the network device or terminal device shown in FIG6 . The method includes:

[0143] Step 310: Receive a frequency offset calibration signal sent by a first device, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, where the at least two sub-signals are respectively part of the frequency offset calibration signal, and the at least two sub-signals are identical when sent.

[0144] Frequency deviation, also known as carrier frequency offset, can occur due to at least one of the following: a clock difference between the transmitter and receiver, caused by a mismatch in the oscillators; or Doppler shift during signal transmission.

[0145] In some embodiments, in order to obtain the frequency offset between the first device and the second device to perform frequency offset calibration, the second device receives a frequency offset calibration signal sent from the first device, and the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, and the at least two sub-signals are respectively part of the frequency offset calibration signal, and at least the two sub-signals are the same when sent.

[0146] In some embodiments, at least two sub-signals are identical, including at least one of: identical waveform; identical data; identical length; identical phase; identical sequences used to generate the at least two sub-signals; and identical formulas used to generate the at least two sub-signals.

[0147] In some embodiments, at least two sub-signals have the same waveform, in other words, at least two sub-signals have the same data, or the sequences used to generate the at least two sub-signals are the same, or the formulas used to generate the at least two sub-signals are the same.

[0148] In some embodiments, since the at least two sub-signals are identical, the lengths of the at least two sub-signals are identical, that is, the phases of the at least two sub-signals are identical.

[0149] In some embodiments, the at least two sub-signals include a first sub-signal and a second sub-signal; the first sub-signal and the second sub-signal are two continuous parts of the frequency deviation calibration signal; or, the first sub-signal and the second sub-signal are two partially overlapping parts of the frequency deviation calibration signal. As shown in FIG8 , the frequency deviation calibration signal 10 includes at least two sub-signals, and the sub-signals include a first sub-signal 11 and a second sub-signal 12. Schematic diagram (1) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two continuous parts of the frequency deviation calibration signal 10; schematic diagram (2) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two partially overlapping parts of the frequency deviation calibration signal 10.

[0150] In some embodiments, at least two sub-signals use at least one of an OFDM waveform, a hybrid waveform of an OFDM waveform and an OOK waveform, a triangle waveform, a square waveform, and a pulse waveform.

[0151] In some embodiments, the subcarrier spacing is at least one of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, 480kHz, 312.5kHz, and 31.25kHz. It should be noted that the subcarrier spacing can also be any value other than the above subcarrier spacing, which is not listed one by one in the embodiments of the present application. Optionally, subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, and 480kHz can be compatible with NR systems; subcarrier spacings of 312.5kHz and 31.25kHz can be compatible with WIFI systems.

[0152] In some embodiments, the frequency offset calibration signal is a periodic signal. One period of the frequency offset calibration signal is the period of a minimum sub-signal that repeatedly appears in the frequency offset calibration signal; or, one period of the frequency offset calibration signal is the time domain length occupied by a minimum sub-signal that repeatedly appears in the frequency offset calibration signal. Each of the at least two sub-signals includes at least one minimum sub-signal.

[0153] In some embodiments, the duration of each of the at least two sub-signals in the time domain is not less than one time domain unit, or the duration of each sub-signal in the time domain is less than one time domain unit. Optionally, when the duration of each sub-signal in the time domain is not less than one time domain unit, the duration of each sub-signal in the time domain is an integer multiple of one time domain unit, or the duration of each sub-signal in the time domain is not an integer multiple of one time domain unit.

[0154] The time domain unit is at least one of a frame, a subframe, a time slot or a symbol. Optionally, the time length of a frame is defined as 10ms; a frame includes 10 subframes, and the time length of a subframe is 1ms; a subframe includes i time slots, i is a positive integer, and the value of i is related to the subcarrier spacing. The larger the subcarrier spacing, the shorter the actual time length of a time slot; a time slot includes 14 symbols, and the symbol can be an OFDM symbol. It should be noted that the time length of a frame can also be defined as other time lengths, such as 15ms, 20ms, etc., which is not limited in the embodiments of the present application.

[0155] Since the frequency offset calibration signal is a periodic signal, one time domain unit includes multiple periods of the frequency offset calibration signal; or, one time domain unit includes one period of the frequency offset calibration signal.

[0156] In some embodiments, each sub-signal of at least two sub-signals occupies multiple time domain units in the time domain; or, occupies one time domain unit in the time domain; or, the duration occupied in the time domain is not a positive integer multiple of a time domain unit, or, the duration occupied in the time domain is less than one time domain unit.

[0157] Exemplarily, one time domain unit is one symbol. Each of the at least two sub-signals occupies 2 symbols in the time domain; or, occupies 1 symbol in the time domain; or, occupies 2.5 symbols in the time domain; or, occupies 0.5 symbols in the time domain.

[0158] In some embodiments, because a time domain unit includes one or more cycles of the frequency offset calibration signal, each of the at least two sub-signals includes, in the time domain, one or more cycles of the frequency offset calibration signal, or a portion of one cycle, or a non-integer multiple of one cycle. For example, each sub-signal includes, in the time domain, one cycle, two cycles, 0.5 cycles, or 2.5 cycles of the frequency offset calibration signal.

[0159] In some embodiments, the interval between the time domain starting positions of each sub-signal in the at least two sub-signals is a positive integer multiple of a period, which is the period of the frequency offset calibration signal.

[0160] In some embodiments, the time domain starting position of each of the at least two sub-signals is spaced apart by less than one time domain unit. For example, a time domain unit is one symbol. As shown in schematic diagram (1) of FIG8 , the first sub-signal 11 and the second sub-signal 12 occupy one symbol, and the time domain starting positions of the first sub-signal 11 and the second sub-signal 12 are spaced apart by half a symbol, i.e., half a time domain unit.

[0161] In some embodiments, the second device receives a signal sent by the first device. When the first device is a terminal device and the second device is an access network device, the second device receives an uplink signal sent by the first device; when the first device is an access network device and the second device is a terminal device, the second device receives a downlink signal sent by the first device.

[0162] In some embodiments, the second device performs frequency offset calibration based on at least two sub-signals used for frequency offset calibration. Exemplarily, the second device performs frequency offset calibration on an uplink signal based on the at least two sub-signals used for frequency offset calibration, where the uplink signal includes at least two sub-signals; or the second device performs frequency offset calibration on a downlink signal based on the at least two sub-signals used for frequency offset calibration, where the downlink signal includes at least two sub-signals.

[0163] In some embodiments, the access network device uses at least two sub-signals to calibrate a first frequency error, where the first frequency error is an error generated when the terminal device sends an uplink signal, and the error includes at least one of an error caused by an error in an oscillator used by the terminal device and an error generated during the transmission of the uplink signal, and the uplink signal includes the at least two sub-signals; or, the terminal device uses at least two sub-signals to calibrate a second frequency error, where the second frequency error is an error generated when the terminal device receives a downlink signal, and the error includes at least one of an error caused by an error in an oscillator used by the terminal device and an error generated during the transmission of the downlink signal; the downlink signal includes at least two sub-signals.

[0164] Exemplarily, a terminal device uses an RC oscillator or an LC oscillator. These two oscillators can cause errors when the terminal device transmits uplink signals and receives downlink signals. When the terminal device transmits an uplink signal, due to errors in the oscillator's frequency accuracy, an error occurs between the actual frequency of the uplink signal transmitted by the terminal device and the theoretical frequency. Furthermore, during uplink signal transmission, Doppler shift may occur, so the uplink signal received by the access network device has a first frequency error. This first frequency error includes at least one of an error caused by an error in the oscillator used by the terminal device and an error generated during the transmission of the uplink signal. When the access network device transmits a downlink signal, due to the high frequency accuracy of the oscillator used by the access network device, errors generally do not occur. However, Doppler shift may occur during the transmission of the downlink signal. Furthermore, due to a mismatch between the terminal device's oscillator and the access network device's oscillator, an error occurs when the terminal device receives the downlink signal. Consequently, the downlink signal received by the terminal device has a second frequency error. This second frequency error includes at least one of an error caused by an error in the oscillator used by the terminal device and an error generated during the transmission of the downlink signal. After receiving the uplink signal or the downlink signal, the second device performs frequency offset calibration on the uplink signal or the downlink signal according to at least two sub-signals in the uplink signal or the downlink signal.

[0165] In some embodiments, the terminal device does not perform frequency offset calibration when sending uplink signals, and still sends according to the theoretical frequency. When the access network device receives the uplink signal, it calculates the frequency offset based on at least two sub-signals used for frequency offset calibration, and then performs calibration.

[0166] In summary, the method provided in the embodiment of the present application performs frequency offset calibration through at least two sub-signals in the received signal. This method does not require a large amount of storage resources or computing resources, nor does it require complex calculations to achieve frequency offset calibration. It is suitable for devices with simple structures such as Ambient IoT devices.

[0167] In an optional embodiment based on FIG. 7 or FIG. 9 , the signal may be represented in a complex form, so the two consecutive sub-signals received by the second device may be represented as:

[0168] Where r1(n) is the first sub-signal received by the second device; r2(n) is the second sub-signal received by the second device; x1(n) is the first sub-signal sent by the first device; x2(n) is the second sub-signal sent by the first device; η(nT s ) is noise; n is the order of sampling points, for example, r1(1) can represent the first sampling point in at least two sub-signals; Ts represents the time interval between sampling points; is the frequency error corresponding to the first sub-signal; is the frequency error corresponding to the second sub-signal; exp j is the exponential form of a complex number, j is the imaginary unit; pi is also π; f is the frequency deviation; N d is the time interval between two consecutive sub-signals, N d It can also be referred to as the interval between the time domain starting positions of each sub-signal in at least two sub-signals; It is the initial phase.

[0169] Multiplying the first sub-signal by the conjugate complex number of the second sub-signal yields:

[0170] Where R is the result of conjugate multiplication; L is the data length of the first sub-signal and the second sub-signal, that is, the number of sampling points; is the complex conjugate of r2(n).

[0171] After expanding the formula, we can get:

[0172] Where η is the noise; is the complex conjugate of x2(n).

[0173] Since at least two sub-signals are the same signal, x1(n)=x2(n). If the effect of noise on the signal is ignored, the above formula can be expressed as:

[0174] It can be deduced that: arg(R)=2*pi*f*N d *T s

[0175] Where arg(R) represents the principal value of the argument of the complex number R.

[0176] Therefore, the frequency deviation f can be expressed as:

[0177] Where, f s is the sampling rate, f s T S The reciprocal of .

[0178] In some embodiments, the frequency deviation f includes at least one of an error caused by an error in an oscillator used by the terminal and an error generated during signal transmission.

[0179] The frequency deviation range can also be deduced as:

[0180] In some embodiments, the frequency deviation range can also be called a sweep frequency range. The above formula shows that the sweep frequency range is related to the time interval N between two consecutive sub-signals. d and the sampling rate f s The time interval N between the sending of two consecutive sub-signals is d The smaller the interval is, that is, the interval between the time domain starting positions of each of the at least two sub-signals, the larger the frequency sweep range is.

[0181] A larger sweep range increases the frequency offset range that can be calibrated. This means a larger error margin is tolerated when the first device sends a signal, or when the second device receives a signal. If the actual frequency error of the signal sent by the second device exceeds the sweep range, the second device will be unable to calibrate the frequency offset of the received signal. To expand the sweep range, the following methods can be used:

[0182] Next, an example is given in which the at least two sub-signals are two sub-signals and the time domain unit is a symbol, but the present application is not limited thereto.

[0183] Step 410: Perform an Inverse Fast Fourier Transform (IFFT) on the n frequency domain sampling points to obtain corresponding n time domain sampling points, where the n time domain sampling points are the time domain sampling points of a time domain unit in the frequency offset calibration signal.

[0184] In some embodiments, the frequency offset calibration signal includes n time domain sampling points in a time domain unit, and the data corresponding to the n time domain sampling points are obtained by performing IFFT on the data corresponding to the n frequency domain sampling points. Optionally, the n frequency domain sampling points include: m first type sampling points whose corresponding data are not zero. The intervals between two adjacent first type sampling points are the same and are 2 k frequency domain sampling intervals; where m is a positive integer greater than or equal to 2, n is a positive integer greater than or equal to m, and k is a non-negative integer. k Refers to the kth power of 2. As shown in Figure 10, there are n frequency domain sampling points, which include m first-type sampling points. The data corresponding to the first-type sampling points are not zero, and the interval between two adjacent first-type sampling points is 2 k frequency domain sampling interval.

[0185] In some embodiments, data corresponding to frequency domain sampling points other than the m first type sampling points among the n frequency domain sampling points are zero.

[0186] In some embodiments, the frequency domain sampling interval is 2 kis the absolute value of the difference between two adjacent first-type sampling points. k is 0, n is 64, and m is 64, meaning all 64 frequency-domain sampling points are first-type sampling points. Alternatively, k is 1, n is 64, and m is a positive integer not greater than 32. For example, the first first-type sampling point is the first frequency-domain sampling point, and the second first-type sampling point is the third frequency-domain sampling point.

[0187] Each symbol obtained in this way is composed of 2 k The signal waveform composed of symbols is a repeated waveform. The sampling interval in the frequency domain is 2 k In the case of IFFT, the repeated data segment corresponding to one symbol after IFFT is also 2 k , that is, 2 k Therefore, the two sub-signals only need to be sent with one repetitive waveform apart to avoid mutual influence, that is, the time interval between the two signals is N. d Reduce to symbol length. According to the above formula of frequency deviation f, it can be deduced that when the time interval between the transmission of two sub-signals is N d Reduce to When the symbol length is 1, the sweep range is extended to ±2 k-1 ×g kHz, where g is the subcarrier spacing selected for transmission.

[0188] The position distribution of the m first-type sampling points among the n frequency domain sampling points includes at least one of the following three distribution modes:

[0189] Distribution method 1: the sampling point positions of the m first-type sampling points include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points; or, the sampling point positions of the m first-type sampling points do not include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points.

[0190] Distribution mode 2: the sampling point positions of the m first type sampling points are the center positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are non-center positions of the n frequency domain sampling points.

[0191] Distribution mode three: the sampling point positions of the m first type sampling points are symmetrical positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are asymmetrical positions of the n frequency domain sampling points.

[0192] In some embodiments, the center position can be understood as not including the first frequency domain sampling point and / or the last frequency domain sampling point; the non-center position can be understood as including the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points.

[0193] Among them, distribution mode 2 and distribution mode 3 can be used in combination, for example, the sampling point positions of the m first type sampling points are the centered symmetrical positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are the centered asymmetric positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are the non-centered symmetrical positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are the non-centered asymmetric positions of the n frequency domain sampling points.

[0194] The sampling point positions of the m first-type sampling points are symmetrical positions of the n frequency-domain sampling points, indicating central symmetry. For example, when n is 8 and k is 0, that is, the interval between two adjacent first-type sampling points is 1, and m is 2, and the sampling point positions of the first-type sampling points are symmetrical positions of the frequency domain sampling points, the first-type sampling points are the 4th frequency domain sampling point and the 5th frequency domain sampling point, respectively. This situation can also be referred to as the sampling point positions of the first-type sampling points being the center positions of the frequency domain sampling points, or the sampling point positions of the first-type sampling points do not include the first frequency domain sampling point and / or the last frequency domain sampling point among the frequency domain sampling points. When n is 8 and k is 3, that is, the interval between two adjacent first-type sampling points is 8, and m is 2, and the sampling point positions of the first-type sampling points are symmetrical positions of the frequency domain sampling points, the first-type sampling points are the 1st frequency domain sampling point and the 8th frequency domain sampling point, respectively. This situation can also be referred to as the sampling point positions of the first-type sampling points being non-center positions of the frequency domain sampling points, or the sampling point positions of the first-type sampling points include the first frequency domain sampling point and / or the last frequency domain sampling point among the frequency domain sampling points.

[0195] For example, n is 64, that is, there are 64 sampling points. If m is 4 and k is 2, then the sampling point positions of the four first-type sampling points are centered asymmetric positions of the 64 frequency-domain sampling points, for example, the sampling point positions of the four first-type sampling points are 27, 31, 35, and 39, respectively. Alternatively, if m is 4, then the sampling point positions of the four first-type sampling points are non-centered asymmetric positions of the 64 frequency-domain sampling points, for example, the sampling point positions of the four first-type sampling points are 1, 5, 9, and 13, or 7, 11, 15, and 19, or 45, 49, 53, and 57. Alternatively, if m is 4 and k is 2, then the sampling point positions of the four first-type sampling points are centered symmetric positions of the 64 frequency-domain sampling points, for example, the sampling point positions of the four first-type sampling points are 26, 30, 34, and 38, respectively.

[0196] For example, for a symbol, n is 64, that is, a symbol has 64 sampling points; when m is 2 and k is 1, the spectrum diagram corresponding to the symbol is shown in Figure 11, and the 31st sampling point and the 33rd sampling point are set as first-type sampling points, and the data corresponding to the first-type sampling points is 1; the data corresponding to the frequency domain sampling points other than the m first-type sampling points is 0. The IFFT of the 64 frequency domain sampling points in the spectrum shown in Figure 11 is performed to obtain the time domain waveform corresponding to a symbol as shown in Figure 12. When the waveform of a symbol is as shown in Figure 12, each symbol is composed of two completely repeated data segments, and the transmission time interval N between two consecutive signals is 0. d It is reduced to half the symbol length, as shown in Figure 13. At this time, the frequency sweep range is expanded to one subcarrier interval. When m is 4 and k is 2, the spectrum diagram corresponding to the symbol is shown in Figure 14. The sampling point position of the first type of sampling point is the asymmetric position centered on the 64 frequency domain sampling points. The IFFT of the 64 frequency domain sampling points in the spectrum shown in Figure 14 is performed to obtain the time domain waveform corresponding to a symbol as shown in Figure 15. When the waveform of a symbol is as shown in Figure 15, each symbol is composed of four completely repeated data segments, and the sending time interval N between two consecutive signals is 1. d It is reduced to 1 / 4 symbol length, and the frequency sweep range is expanded to two subcarrier intervals.

[0197] It should be noted that the value of k can be 0. When the value of k is 0, the time domain waveform corresponding to one symbol obtained by performing IFFT on the 64 frequency domain sampling points in the spectrum has no repeated data, so the sending time interval N between two consecutive signals is d The length of the symbol is one, and the sweep range is half the subcarrier spacing.

[0198] To sum up, the method provided in the embodiment of the present application can make the interval between the time domain starting positions of each sub-signal in at least two sub-signals less than one time domain unit, thereby expanding the scanning range. Using this method, the second device does not need to perform special processing when receiving the signal, and no additional resource consumption is added to the second device.

[0199] In the optional embodiments based on FIG. 7 or FIG. 9 , the frequency sweep range is expanded, but the waveform finally obtained is not flat in the time domain and the frequency domain. The uneven waveform means that the energy will be more concentrated when the signal is sent, which is not conducive to signal transmission. Therefore, the following two schemes are proposed. It should be noted that the following two schemes can be executed simultaneously or one of them can be executed selectively.

[0200] Solution 1: time domain flattening;

[0201] Option 2: frequency domain flattening.

[0202] The following text introduces the above two implementation methods in turn, but the order of introduction of the two implementation methods does not limit the advantages and disadvantages of the two implementation methods.

[0203] Solution 1: time domain flattening.

[0204] The time domain flattening is performed on the first type of sampling points in the spectrum graph, and the data corresponding to the m first type of sampling points are determined based on at least one of the following information:

[0205] A sequence of all 1s;

[0206] ·First sequence;

[0207] A partial sequence of the first sequence;

[0208] First modulation information;

[0209] Pseudo-random ±1 sequence;

[0210] The first sequence includes at least one of a ZC sequence, a PN sequence, an m sequence, and a Gold sequence; and the first modulation information includes at least one of QPSK (Quadrature Phase Shift Keying) modulation information and QAM (Quadrature Amplitude Modulation) modulation information.

[0211] Exemplarily, when the data corresponding to the m first-type sampling points is 1, the corresponding frequency spectrum and time-domain waveform are as shown in FIG11 and FIG12 or FIG14 and FIG15 , which are not described in detail here.

[0212] Exemplarily, the data corresponding to m first-type sampling points are determined based on a first sequence, where the first sequence is a randomized sequence, or the first sequence is a pseudo-random sequence, and the first sequence includes at least one of a ZC sequence, a PN sequence, an m sequence, and a Gold sequence. Figure 16 shows a frequency spectrum diagram where n is 64, m is 16, and k is 2, and the data corresponding to the first-type sampling points are determined based on the ZC sequence. Figure 17 is a time domain waveform diagram obtained after performing IFFT on the sampling points in the frequency spectrum diagram corresponding to Figure 16. When the data corresponding to the m first-type sampling points are determined based on a partial sequence of the first sequence, the resulting frequency spectrum diagram and time domain waveform diagram are similar to those of the first-type sampling points determined based on the first sequence, and are not further described here. The data corresponding to the first-type sampling points have a one-to-one correspondence with the sequence elements in the first sequence.

[0213] Exemplarily, the data corresponding to m first-type sampling points is determined based on first modulation information, where the first modulation information includes at least one of QPSK modulation information and QAM modulation information. Figure 18 shows a frequency spectrum where n is 64, m is 4, and k is 2, and the data corresponding to the first-type sampling points is determined based on QPSK modulation information. Figure 19 shows a time-domain waveform obtained by performing an IFFT on the sampling points in the frequency spectrum corresponding to Figure 18.

[0214] Exemplarily, the data corresponding to m first-type sampling points is determined based on a pseudo-random ±1 sequence. Figure 20 shows a spectrum diagram where n is 64, m is 4, and k is 2, and the data corresponding to the first-type sampling points is determined based on a pseudo-random ±1 sequence. Figure 21 shows a time-domain waveform diagram obtained by performing an IFFT on the sampling points in the spectrum diagram corresponding to Figure 20.

[0215] In addition to the above-mentioned methods of using a single piece of information to determine the data corresponding to the first type of sampling point, several pieces of information can also be combined for determination. For example, combining the first sequence and the pseudo-random ±1 sequence, the first sequence uses a ZC sequence, and multiplying the ZC sequence with the pseudo-random ±1 sequence to obtain data corresponding to m first type sampling points; or, combining the first modulation information and the pseudo-random ±1 sequence, the first modulation information is QPSK modulation information, and multiplying the QPSK modulation information with the pseudo-random ±1 sequence to obtain data corresponding to m first type sampling points. In summary, the method provided in the embodiment of the present application performs random processing on the frequency domain information during the signal generation process, thereby ensuring the flatness of the time domain waveform, avoiding signal distortion and saturation of the power amplifier, and facilitating signal transmission.

[0216] Option 2: frequency domain flattening.

[0217] Frequency domain flattening can be understood as randomizing the frequency offset calibration signal during its generation. Optionally, the frequency offset calibration signal is multiplied by a random sequence to obtain a randomized frequency offset calibration signal. The random sequence includes multiple random sequence elements, each of which is at least one of the following:

[0218] Multiple random sequence elements are random.

[0219] The random sequence elements corresponding to the time domain sampling points within a time domain unit are the same, and the random sequence elements corresponding to the time domain sampling points in different time domain units are random.

[0220] The random sequence elements corresponding to the time domain sampling points within one cycle are the same, and the random sequence elements corresponding to the time domain sampling points in different cycles are random.

[0221] The random sequence elements corresponding to the time domain sampling points within a time domain unit are random, and the random sequence elements corresponding to the time domain sampling points in different time domain units are the same.

[0222] The random sequence elements corresponding to the time domain sampling points within one cycle are random, and the random sequence elements corresponding to the time domain sampling points in different cycles are the same.

[0223] In some embodiments, when the frequency offset calibration signal is multiplied by the random sequence, the i-th time domain sampling point is multiplied by the i-th random sequence element in the random sequence. For example, if there are four time domain sampling points, their corresponding data is {1, 0, 1, 0}, and the random sequence is {x1, x2, x3, x4}, the randomized result obtained after multiplication is {x1, 0, x3, 0}.

[0224] In some embodiments, after randomization processing is performed on the frequency offset calibration signal, the randomized frequency offset calibration signal is sent.

[0225] Exemplarily, the random sequence elements corresponding to the time domain sampling points of multiple random sequence elements in one time domain unit are the same, and the random sequence elements corresponding to the time domain sampling points in different time domain units are random. For example, the random sequence elements corresponding to the time domain sampling points in the first time domain unit are all 1, the random sequence elements corresponding to the time domain sampling points in the second time domain unit are all 2, and the random sequence elements corresponding to the time domain sampling points in the third time domain unit are all 3.

[0226] Exemplarily, the random sequence elements corresponding to the time domain sampling points within one period of multiple random sequence elements are random, and the random sequence elements corresponding to the time domain sampling points in different periods are the same. For example, the random sequence elements corresponding to the time domain sampling points in different periods are all "123456".

[0227] After receiving the frequency-domain flattened frequency offset calibration signal, the second device can derandomize the frequency offset calibration signal. Derandomization involves multiplying the frequency offset calibration signal by conj(random sequence). The conj() method can be used to obtain the conjugate value of the random sequence. Let the unrandomized frequency offset calibration signal be denoted as A, and the random sequence be denoted as B. The result obtained after randomizing the frequency offset calibration signal is A*B; derandomization is equivalent to A*B*conj(B). Since conj(B) is the conjugate value of B, B*conj(B) is |B| 2 , that is, the square of the random sequence modulus; thus, the frequency offset calibration signal A without randomization processing can be calculated.

[0228] In summary, the method provided in the embodiment of the present application performs randomization processing during the generation of the frequency offset calibration signal, which can alleviate the problem of spectrum energy concentration and flatten the spectrum energy, thereby improving frequency selectivity and anti-interference capability.

[0229] In some embodiments, step 410 and step 420 can be implemented as independent embodiments, such as being implemented separately as a frequency sweep range expansion method and a signal waveform determination method; scheme one can be implemented as an independent embodiment, such as being implemented separately as a time domain flattening method; scheme two can be implemented as an independent embodiment, such as being implemented separately as a frequency domain flattening method and a signal randomization method; step 210, step 410 and step 420 can be implemented as independent embodiments; step 210 and scheme one can be implemented as independent embodiments; step 210 and scheme two can be implemented as independent embodiments; step 210, step 410, step 420 and scheme one can be implemented as independent embodiments; step 210, step 410, step 420 and scheme two can be implemented as independent embodiments; step 210, step 410, step 420, scheme one and scheme two can be implemented as independent embodiments. Step 310, step 410 and step 420 can be implemented as independent embodiments; step 310 and solution one can be implemented as independent embodiments; step 310 and solution two can be implemented as independent embodiments; step 310, step 410, step 420 and solution one can be implemented as independent embodiments; step 310, step 410, step 420 and solution two can be implemented as independent embodiments; step 310, step 410, step 420, solution one and solution two can be implemented as independent embodiments.

[0230] FIG22 shows an overall flow chart of a frequency offset calibration method provided by an exemplary embodiment of the present application. The method includes:

[0231] Step 150: The terminal device sends a frequency deviation calibration signal to the network device.

[0232] In some embodiments, a terminal device transmits a frequency offset calibration signal to a network device. The frequency offset calibration signal includes at least two sub-signals used for frequency offset calibration. The at least two sub-signals are each part of the frequency offset calibration signal, and the at least two sub-signals are identical. Due to errors in an oscillator used by the terminal device, there is an error between the theoretical frequency and the actual frequency of the at least two sub-signals. For example, the at least two sub-signals are transmitted with a target frequency of 100 kHz, but due to errors in the oscillator used by the terminal device, the actual frequency of the at least two sub-signals when transmitted is 120 kHz.

[0233] Step 151: The network device calculates a first frequency error based on the frequency offset calibration signal.

[0234] In some embodiments, the network device calculates a first frequency error based on a received frequency deviation calibration signal, that is, the network device calculates a first frequency error based on at least two received sub-signals, and the first frequency error includes at least one of an error caused by an error in an oscillator used by the terminal device and an error generated during the transmission of the uplink signal.

[0235] Step 152: The terminal device sends at least one uplink signal to the network device.

[0236] In some embodiments, the terminal device sends at least one uplink signal to the network device. The at least one uplink signal is sent after the frequency offset calibration signal is sent; or the at least one uplink signal is sent simultaneously with the frequency offset calibration signal; or the at least one uplink signal includes the frequency offset calibration signal.

[0237] Step 153: The network device calibrates at least one uplink signal based on the first frequency error.

[0238] In some embodiments, the network device calibrates at least one uplink signal based on the calculated first frequency error.

[0239] In some embodiments, step 150 and step 152 may be performed simultaneously; step 151 and step 152 may be performed in an exchanged order or simultaneously.

[0240] To sum up, the method provided in the embodiment of the present application uses a frequency deviation calibration method to calibrate the uplink signal sent by the terminal device including a first frequency error. The first frequency error is calculated based on the frequency deviation calibration signal. This method is simple to operate and can calibrate the frequency deviation of the Ambient IoT device caused by the oscillator error.

[0241] FIG23 shows an overall flow chart of a frequency offset calibration method provided by an exemplary embodiment of the present application. The method includes:

[0242] Step 160: The network device sends a frequency offset calibration signal to the terminal device.

[0243] In some embodiments, the network device sends a frequency deviation calibration signal to the terminal device, and the frequency deviation calibration signal includes at least two sub-signals for frequency deviation calibration, at least two sub-signals are respectively part of the frequency deviation calibration signal, and at least two sub-signals are the same. Since the frequency accuracy of the oscillator used by the network device is relatively high, generally no error will occur, but Doppler frequency shift may be generated during the transmission of the frequency deviation calibration signal.

[0244] Step 161: The terminal device calculates a second frequency error based on the frequency offset calibration signal.

[0245] In some embodiments, due to the mismatch between the oscillator of the terminal device and the oscillator of the access network device, the terminal device may generate an error when receiving the frequency offset calibration signal.

[0246] In some embodiments, the terminal device calculates a second frequency error based on a received frequency deviation calibration signal, that is, the terminal device calculates a second frequency error based on at least two received sub-signals, and the second frequency error includes at least one of an error caused by an error in an oscillator used by the terminal device and an error generated during the transmission of the downlink signal.

[0247] Step 162: The network device sends at least one downlink signal to the terminal device.

[0248] In some embodiments, the network device sends at least one downlink signal to the terminal device. The at least one downlink signal is sent after the frequency offset calibration signal is sent; or the at least one downlink signal is sent simultaneously with the frequency offset calibration signal; or the at least one downlink signal includes the frequency offset calibration signal.

[0249] Step 163: The terminal device calibrates at least one downlink signal based on the second frequency error.

[0250] In some embodiments, the terminal device calibrates at least one downlink signal based on the calculated second frequency error.

[0251] In some embodiments, step 160 and step 162 may be performed simultaneously; step 161 and step 162 may be performed in an exchanged order or simultaneously.

[0252] To sum up, the method provided in the embodiment of the present application uses a frequency deviation calibration method to calibrate the downlink signal including the second frequency error sent by the network device. The second frequency error is calculated based on the frequency deviation calibration signal. This method is simple to operate and can be applied to Ambient IoT devices for frequency deviation calibration.

[0253] FIG24 shows a structural block diagram of a frequency offset calibration apparatus provided by an exemplary embodiment of the present application. The apparatus may be implemented as a part of a first device, which may be the network device or terminal device shown in FIG6 . The apparatus includes:

[0254] The generating module 510 is configured to generate a frequency offset calibration signal, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, where the at least two sub-signals are respectively part of the frequency offset calibration signal, and at least the two sub-signals are identical.

[0255] In some embodiments, at least two sub-signals are identical, including at least one of: identical waveform; identical data; identical length; identical phase; identical sequences used to generate the at least two sub-signals; and identical formulas used to generate the at least two sub-signals.

[0256] In some embodiments, at least two sub-signals have the same waveform, in other words, at least two sub-signals have the same data, or the sequences used to generate the at least two sub-signals are the same, or the formulas used to generate the at least two sub-signals are the same.

[0257] In some embodiments, since the at least two sub-signals are identical, the lengths of the at least two sub-signals are identical, that is, the phases of the at least two sub-signals are identical.

[0258] In some embodiments, the at least two sub-signals include a first sub-signal and a second sub-signal; the first sub-signal and the second sub-signal are two continuous parts of the frequency deviation calibration signal; or, the first sub-signal and the second sub-signal are two partially overlapping parts of the frequency deviation calibration signal. As shown in FIG8 , the frequency deviation calibration signal 10 includes at least two sub-signals, and the sub-signals include a first sub-signal 11 and a second sub-signal 12. Schematic diagram (1) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two continuous parts of the frequency deviation calibration signal 10; schematic diagram (2) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two partially overlapping parts of the frequency deviation calibration signal 10.

[0259] In some embodiments, at least two sub-signals use at least one of an OFDM waveform, a hybrid waveform of an OFDM waveform and an OOK waveform, a triangle waveform, a square waveform, and a pulse waveform.

[0260] In some embodiments, the subcarrier spacing is at least one of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, 480kHz, 312.5kHz, and 31.25kHz. It should be noted that the subcarrier spacing can also be any value other than the above subcarrier spacing, which is not listed one by one in the embodiments of the present application. Optionally, subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, and 480kHz can be compatible with NR systems; subcarrier spacings of 312.5kHz and 31.25kHz can be compatible with WIFI systems.

[0261] In some embodiments, the frequency offset calibration signal is a periodic signal. One period of the frequency offset calibration signal is the period of a minimum sub-signal that repeatedly appears in the frequency offset calibration signal; or, one period of the frequency offset calibration signal is the time domain length occupied by a minimum sub-signal that repeatedly appears in the frequency offset calibration signal. Each of the at least two sub-signals includes at least one minimum sub-signal.

[0262] In some embodiments, the duration of each of the at least two sub-signals in the time domain is not less than one time domain unit, or the duration of each sub-signal in the time domain is less than one time domain unit. Optionally, when the duration of each sub-signal in the time domain is not less than one time domain unit, the duration of each sub-signal in the time domain is an integer multiple of one time domain unit, or the duration of each sub-signal in the time domain is not an integer multiple of one time domain unit.

[0263] The time domain unit is at least one of a frame, a subframe, a time slot or a symbol. Optionally, the time length of a frame is defined as 10ms; a frame includes 10 subframes, and the time length of a subframe is 1ms; a subframe includes i time slots, i is a positive integer, and the value of i is related to the subcarrier spacing. The larger the subcarrier spacing, the shorter the actual time length of a time slot; a time slot includes 14 symbols, and the symbol can be an OFDM symbol. It should be noted that the time length of a frame can also be defined as other time lengths, such as 15ms, 20ms, etc., which is not limited in the embodiments of the present application.

[0264] Since the frequency offset calibration signal is a periodic signal, one time domain unit includes multiple periods of the frequency offset calibration signal; or, one time domain unit includes one period of the frequency offset calibration signal.

[0265] In some embodiments, each sub-signal of at least two sub-signals occupies multiple time domain units in the time domain; or, occupies one time domain unit in the time domain; or, the duration occupied in the time domain is not a positive integer multiple of a time domain unit, or, the duration occupied in the time domain is less than one time domain unit.

[0266] Exemplarily, one time domain unit is one symbol. Each of the at least two sub-signals occupies 2 symbols in the time domain; or, occupies 1 symbol in the time domain; or, occupies 2.5 symbols in the time domain; or, occupies 0.5 symbols in the time domain.

[0267] In some embodiments, because a time domain unit includes one or more cycles of the frequency offset calibration signal, each of the at least two sub-signals includes, in the time domain, one or more cycles of the frequency offset calibration signal, or a portion of one cycle, or a non-integer multiple of one cycle. For example, each sub-signal includes, in the time domain, one cycle, two cycles, 0.5 cycles, or 2.5 cycles of the frequency offset calibration signal.

[0268] In some embodiments, the interval between the time domain starting positions of each sub-signal in the at least two sub-signals is a positive integer multiple of a period, which is the period of the frequency offset calibration signal.

[0269] In some embodiments, the time domain starting position of each of the at least two sub-signals is spaced apart by less than one time domain unit. For example, a time domain unit is one symbol. As shown in schematic diagram (1) of FIG8 , the first sub-signal 11 and the second sub-signal 12 occupy one symbol, and the time domain starting positions of the first sub-signal 11 and the second sub-signal 12 are spaced apart by half a symbol, i.e., half a time domain unit.

[0270] The sending module 520 is configured to send a frequency offset calibration signal to the second device.

[0271] Frequency deviation, also known as carrier frequency offset (CFO), can occur due to at least one of the following: a clock difference between the transmitter and receiver, caused by a mismatch in the oscillators; or Doppler shift during signal transmission.

[0272] In some embodiments, in order to obtain the frequency offset between the first device and the second device for frequency offset calibration, the first device sends a frequency offset calibration signal to the second device, and the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, and the at least two sub-signals are respectively part of the frequency offset calibration signal, and at least the two sub-signals are the same.

[0273] To summarize, the device provided in the embodiment of the present application performs frequency offset calibration by sending a frequency offset calibration signal. The frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, where at least two sub-signals are the same. The device does not require a large amount of storage resources or computing resources, nor does it require complex calculations to achieve frequency offset calibration. It is suitable for devices with simple structures such as Ambient IoT devices.

[0274] FIG25 shows a structural block diagram of a frequency offset calibration apparatus provided by an exemplary embodiment of the present application. The apparatus may be implemented as a part of a second device, which may be the network device or terminal device shown in FIG6 . The apparatus includes:

[0275] The receiving module 610 is used to receive a frequency offset calibration signal sent by the first device. The frequency offset calibration signal includes at least two sub-signals for frequency offset calibration. The at least two sub-signals are respectively part of the frequency offset calibration signal, and the at least two sub-signals are the same when sent.

[0276] Frequency deviation, also known as carrier frequency offset, can occur due to at least one of the following: a clock difference between the transmitter and receiver, caused by a mismatch in the oscillators; or Doppler shift during signal transmission.

[0277] In some embodiments, in order to obtain the frequency offset between the first device and the second device to perform frequency offset calibration, the second device receives a frequency offset calibration signal sent from the first device, and the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, and the at least two sub-signals are respectively part of the frequency offset calibration signal, and at least the two sub-signals are the same when sent.

[0278] In some embodiments, at least two sub-signals are identical, including at least one of: identical waveform; identical data; identical length; identical phase; identical sequences used to generate the at least two sub-signals; and identical formulas used to generate the at least two sub-signals.

[0279] In some embodiments, at least two sub-signals have the same waveform, in other words, at least two sub-signals have the same data, or the sequences used to generate the at least two sub-signals are the same, or the formulas used to generate the at least two sub-signals are the same.

[0280] In some embodiments, since the at least two sub-signals are identical, the lengths of the at least two sub-signals are identical, that is, the phases of the at least two sub-signals are identical.

[0281] In some embodiments, the at least two sub-signals include a first sub-signal and a second sub-signal; the first sub-signal and the second sub-signal are two continuous parts of the frequency deviation calibration signal; or, the first sub-signal and the second sub-signal are two partially overlapping parts of the frequency deviation calibration signal. As shown in FIG8 , the frequency deviation calibration signal 10 includes at least two sub-signals, and the sub-signals include a first sub-signal 11 and a second sub-signal 12. Schematic diagram (1) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two continuous parts of the frequency deviation calibration signal 10; schematic diagram (2) of FIG8 shows a situation where the first sub-signal 11 and the second sub-signal 12 are two partially overlapping parts of the frequency deviation calibration signal 10.

[0282] In some embodiments, at least two sub-signals use at least one of an OFDM waveform, a hybrid waveform of an OFDM waveform and an OOK waveform, a triangle waveform, a square waveform, and a pulse waveform.

[0283] In some embodiments, the subcarrier spacing is at least one of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, 480kHz, 312.5kHz, and 31.25kHz. It should be noted that the subcarrier spacing can also be any value other than the above subcarrier spacing, which is not listed one by one in the embodiments of the present application. Optionally, subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, and 480kHz can be compatible with NR systems; subcarrier spacings of 312.5kHz and 31.25kHz can be compatible with WIFI systems.

[0284] In some embodiments, the frequency offset calibration signal is a periodic signal. One period of the frequency offset calibration signal is the period of a minimum sub-signal that repeatedly appears in the frequency offset calibration signal; or, one period of the frequency offset calibration signal is the time domain length occupied by a minimum sub-signal that repeatedly appears in the frequency offset calibration signal. Each of the at least two sub-signals includes at least one minimum sub-signal.

[0285] In some embodiments, the duration of each of the at least two sub-signals in the time domain is not less than one time domain unit, or the duration of each sub-signal in the time domain is less than one time domain unit. Optionally, when the duration of each sub-signal in the time domain is not less than one time domain unit, the duration of each sub-signal in the time domain is an integer multiple of one time domain unit, or the duration of each sub-signal in the time domain is not an integer multiple of one time domain unit.

[0286] The time domain unit is at least one of a frame, a subframe, a time slot or a symbol. Optionally, the time length of a frame is defined as 10ms; a frame includes 10 subframes, and the time length of a subframe is 1ms; a subframe includes i time slots, i is a positive integer, and the value of i is related to the subcarrier spacing. The larger the subcarrier spacing, the shorter the actual time length of a time slot; a time slot includes 14 symbols, and the symbol can be an OFDM symbol. It should be noted that the time length of a frame can also be defined as other time lengths, such as 15ms, 20ms, etc., which is not limited in the embodiments of the present application.

[0287] Since the frequency offset calibration signal is a periodic signal, one time domain unit includes multiple periods of the frequency offset calibration signal; or, one time domain unit includes one period of the frequency offset calibration signal.

[0288] In some embodiments, each sub-signal of at least two sub-signals occupies multiple time domain units in the time domain; or, occupies one time domain unit in the time domain; or, the duration occupied in the time domain is not a positive integer multiple of a time domain unit, or, the duration occupied in the time domain is less than one time domain unit.

[0289] Exemplarily, one time domain unit is one symbol. Each of the at least two sub-signals occupies 2 symbols in the time domain; or, occupies 1 symbol in the time domain; or, occupies 2.5 symbols in the time domain; or, occupies 0.5 symbols in the time domain.

[0290] In some embodiments, because a time domain unit includes one or more cycles of the frequency offset calibration signal, each of the at least two sub-signals includes, in the time domain, one or more cycles of the frequency offset calibration signal, or a portion of one cycle, or a non-integer multiple of one cycle. For example, each sub-signal includes, in the time domain, one cycle, two cycles, 0.5 cycles, or 2.5 cycles of the frequency offset calibration signal.

[0291] In some embodiments, the interval between the time domain starting positions of each sub-signal in the at least two sub-signals is a positive integer multiple of a period, which is the period of the frequency offset calibration signal.

[0292] In some embodiments, the time domain starting position of each of the at least two sub-signals is spaced apart by less than one time domain unit. For example, a time domain unit is one symbol. As shown in schematic diagram (1) of FIG8 , the first sub-signal 11 and the second sub-signal 12 occupy one symbol, and the time domain starting positions of the first sub-signal 11 and the second sub-signal 12 are spaced apart by half a symbol, i.e., half a time domain unit.

[0293] In some embodiments, the second device receives a signal sent by the first device. When the first device is a terminal device and the second device is an access network device, the second device receives an uplink signal sent by the first device; when the first device is an access network device and the second device is a terminal device, the second device receives a downlink signal sent by the first device.

[0294] The receiving module 610 is further configured to cause the second device to perform frequency offset calibration based on the at least two sub-signals used for frequency offset calibration. Exemplarily, the second device performs frequency offset calibration on an uplink signal based on the at least two sub-signals used for frequency offset calibration, where the uplink signal includes the at least two sub-signals; or the second device performs frequency offset calibration on a downlink signal based on the at least two sub-signals used for frequency offset calibration, where the downlink signal includes the at least two sub-signals.

[0295] The receiving module 610 is further configured to calibrate, by the access network device, a first frequency error using at least two sub-signals, where the first frequency error is an error generated when the terminal device sends an uplink signal, the error including at least one of an error caused by an error in an oscillator used by the terminal device and an error generated during transmission of the uplink signal, the uplink signal including the at least two sub-signals; or

[0296] The receiving module 610 is also used for the terminal device to calibrate a second frequency error using at least two sub-signals. The second frequency error is an error generated when the terminal device receives a downlink signal. The error includes at least one of an error caused by an error in an oscillator used by the terminal device and an error generated during the transmission of the downlink signal; the downlink signal includes at least two sub-signals.

[0297] Exemplarily, a terminal device uses an RC oscillator or an LC oscillator. These two oscillators can cause errors when the terminal device transmits uplink signals and receives downlink signals. When the terminal device transmits an uplink signal, due to errors in the oscillator's frequency accuracy, the actual frequency of the uplink signal transmitted by the terminal device differs from the theoretical frequency. Furthermore, during uplink signal transmission, Doppler shift may occur, so the uplink signal received by the access network device has a first frequency error. This first frequency error includes at least one of an error caused by an error in the oscillator used by the terminal and an error generated during uplink signal transmission. When the access network device transmits a downlink signal, due to the high frequency accuracy of the oscillator used by the access network device, errors generally do not occur. However, Doppler shift may occur during downlink signal transmission. Furthermore, due to a mismatch between the terminal device's oscillator and the access network device's oscillator, the terminal device may generate errors when receiving downlink signals. Consequently, the downlink signal received by the terminal device has a second frequency error. This second frequency error includes at least one of an error caused by an error in the oscillator used by the terminal and an error generated during downlink signal transmission. After receiving the uplink signal or the downlink signal, the second device performs frequency offset calibration on the uplink signal or the downlink signal according to at least two sub-signals in the uplink signal or the downlink signal.

[0298] In some embodiments, the terminal device does not perform frequency offset calibration when sending uplink signals, and still sends according to the theoretical frequency. When the access network device receives the uplink signal, it calculates the frequency offset based on at least two sub-signals used for frequency offset calibration, and then performs calibration.

[0299] In summary, the device provided in the embodiment of the present application performs frequency offset calibration through at least two sub-signals in the received signal. The device does not require a large amount of storage resources or computing resources, nor does it require complex calculations to achieve frequency offset calibration. It is suitable for devices with simple structures such as Ambient IoT devices.

[0300] Signals can be expressed in complex form, so the two consecutive signals received by the second device can be expressed as:

[0301] Where r1(n) is the first sub-signal received by the second device; r2(n) is the second sub-signal received by the second device; x1(n) is the first sub-signal sent by the first device; x2(n) is the second sub-signal sent by the first device; η(nT s ) is noise; n is the sampling point order, for example, r1(1) can represent the first sampling point in at least two sub-signals; T S Indicates the time interval of sampling points; is the frequency error corresponding to the first sub-signal; is the frequency error corresponding to the second sub-signal; exp j is the exponential form of a complex number, j is the imaginary unit; pi is also π; f is the frequency deviation; N d is the time interval between two consecutive sub-signals, N d It can also be referred to as the interval between the time domain starting positions of each sub-signal in at least two sub-signals; It is the initial phase.

[0302] Multiplying the first sub-signal by the conjugate complex number of the second sub-signal yields:

[0303] Where R is the result of conjugate multiplication; L is the data length of the first sub-signal and the second sub-signal, that is, the number of sampling points; is the complex conjugate of r2(n).

[0304] After expanding the formula, we can get:

[0305] Where η is the noise; is the complex conjugate of x2(n).

[0306] Since at least two sub-signals are the same signal, x1(n)=x2(n). If the effect of noise on the signal is ignored, the above formula can be expressed as:

[0307] It can be deduced that: arg(R)=2*pi*f*N d *T s

[0308] Where arg(R) represents the principal value of the argument of the complex number R.

[0309] Therefore, the frequency deviation f can be expressed as:

[0310] Where, f s is the sampling rate, f s T s The reciprocal of .

[0311] In some embodiments, the frequency deviation f includes at least one of an error caused by an error in an oscillator used by the terminal and an error generated during signal transmission.

[0312] The frequency deviation range can also be deduced as:

[0313] In some embodiments, the frequency deviation range can also be called a sweep frequency range. The above formula shows that the sweep frequency range is related to the time interval N between two consecutive sub-signals. d and the sampling rate f s The time interval N between the sending of two consecutive sub-signals is d The smaller the interval is, that is, the interval between the time domain starting positions of each of the at least two sub-signals, the larger the frequency sweep range is.

[0314] The larger the sweep range, the greater the frequency deviation range that can be calibrated. This means the first device can tolerate a larger error when sending a signal, or the second device can tolerate a larger error when receiving a signal. When the second device receives a signal, if the actual frequency error of the signal sent is greater than the sweep range, the second device will be unable to calibrate the frequency deviation of the received signal. To expand the sweep range, the following methods can be used:

[0315] Next, an example is given in which the at least two sub-signals are two sub-signals and the time domain unit is a symbol, but the present application is not limited thereto.

[0316] An inverse Fast Fourier Transform (IFFT) is performed on the n frequency domain sampling points to obtain corresponding n time domain sampling points, where the n time domain sampling points are the time domain sampling points of a time domain unit in the frequency offset calibration signal.

[0317] In some embodiments, the frequency offset calibration signal includes n time domain sampling points in a time domain unit, and the data corresponding to the n time domain sampling points are obtained by performing IFFT on the data corresponding to the n frequency domain sampling points. Optionally, the n frequency domain sampling points include: m first type sampling points whose corresponding data are not zero. The intervals between two adjacent first type sampling points are the same and are 2 k frequency domain sampling intervals; where m is a positive integer greater than or equal to 2, n is a positive integer greater than or equal to m, and k is a non-negative integer. k Refers to the kth power of 2. As shown in Figure 10, there are n frequency domain sampling points, which include m first-type sampling points. The data corresponding to the first-type sampling points are not zero, and the interval between two adjacent first-type sampling points is 2 k frequency domain sampling interval.

[0318] In some embodiments, data corresponding to frequency domain sampling points other than the m first type sampling points among the n frequency domain sampling points are zero.

[0319] In some embodiments, the frequency domain sampling interval is 2 kis the absolute value of the difference between two adjacent first-type sampling points. k is 0, n is 64, and m is 64, meaning all 64 frequency-domain sampling points are first-type sampling points. Alternatively, k is 1, n is 64, and m is a positive integer not greater than 32. For example, the first first-type sampling point is the first frequency-domain sampling point, and the second first-type sampling point is the third frequency-domain sampling point.

[0320] Each symbol obtained in this way is composed of 2 k The signal waveform composed of symbols is a repeated waveform. The sampling interval in the frequency domain is 2 k In the case of IFFT, the repeated data segment corresponding to one symbol after IFFT is also 2 k , that is, 2 k Therefore, the two sub-signals only need to be sent with one repetitive waveform apart to avoid mutual influence, that is, the time interval between the two signals is N. d Reduce to symbol length. According to the above formula of frequency deviation f, it can be deduced that when the time interval between the transmission of two sub-signals is N d Reduce to When the symbol length is 1, the sweep range is extended to ±2 k-1 ×g kHz, where g is the subcarrier spacing selected for transmission.

[0321] The position distribution of the m first-type sampling points among the n frequency domain sampling points includes at least one of the following three distribution modes:

[0322] Distribution method 1: the sampling point positions of the m first-type sampling points include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points; or, the sampling point positions of the m first-type sampling points do not include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points.

[0323] Distribution mode 2: the sampling point positions of the m first type sampling points are the center positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are non-center positions of the n frequency domain sampling points.

[0324] Distribution mode three: the sampling point positions of the m first type sampling points are symmetrical positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are asymmetrical positions of the n frequency domain sampling points.

[0325] In some embodiments, the center position can be understood as not including the first frequency domain sampling point and / or the last frequency domain sampling point; the non-center position can be understood as including the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points.

[0326] Among them, distribution mode 2 and distribution mode 3 can be used in combination, for example, the sampling point positions of the m first type sampling points are the centered symmetrical positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are the centered asymmetric positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are the non-centered symmetrical positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are the non-centered asymmetric positions of the n frequency domain sampling points.

[0327] The sampling point positions of the m first-type sampling points are symmetrical positions of the n frequency-domain sampling points, indicating central symmetry. For example, when n is 8 and k is 0, that is, the interval between two adjacent first-type sampling points is 1, and m is 2, and the sampling point positions of the first-type sampling points are symmetrical positions of the frequency domain sampling points, the first-type sampling points are the 4th frequency domain sampling point and the 5th frequency domain sampling point, respectively. This situation can also be referred to as the sampling point positions of the first-type sampling points being the center positions of the frequency domain sampling points, or the sampling point positions of the first-type sampling points do not include the first frequency domain sampling point and / or the last frequency domain sampling point among the frequency domain sampling points. When n is 8 and k is 3, that is, the interval between two adjacent first-type sampling points is 8, and m is 2, and the sampling point positions of the first-type sampling points are symmetrical positions of the frequency domain sampling points, the first-type sampling points are the 1st frequency domain sampling point and the 8th frequency domain sampling point, respectively. This situation can also be referred to as the sampling point positions of the first-type sampling points being non-center positions of the frequency domain sampling points, or the sampling point positions of the first-type sampling points include the first frequency domain sampling point and / or the last frequency domain sampling point among the frequency domain sampling points.

[0328] For example, n is 64, that is, there are 64 sampling points. If m is 4 and k is 2, then the sampling point positions of the four first-type sampling points are centered asymmetric positions of the 64 frequency-domain sampling points, for example, the sampling point positions of the four first-type sampling points are 27, 31, 35, and 39, respectively. Alternatively, if m is 4, then the sampling point positions of the four first-type sampling points are non-centered asymmetric positions of the 64 frequency-domain sampling points, for example, the sampling point positions of the four first-type sampling points are 1, 5, 9, and 13, or 7, 11, 15, and 19, or 45, 49, 53, and 57. Alternatively, if m is 4 and k is 2, then the sampling point positions of the four first-type sampling points are centered symmetric positions of the 64 frequency-domain sampling points, for example, the sampling point positions of the four first-type sampling points are 26, 30, 34, and 38, respectively.

[0329] For example, for a symbol, n is 64, that is, a symbol has 64 sampling points; when m is 2 and k is 1, the spectrum diagram corresponding to the symbol is shown in Figure 11, and the 31st sampling point and the 33rd sampling point are set as first-type sampling points, and the data corresponding to the first-type sampling points is 1; the data corresponding to the frequency domain sampling points other than the m first-type sampling points is 0. The IFFT of the 64 frequency domain sampling points in the spectrum shown in Figure 11 is performed to obtain the time domain waveform corresponding to a symbol as shown in Figure 12. When the waveform of a symbol is as shown in Figure 12, each symbol is composed of two completely repeated data segments, and the transmission time interval N between two consecutive signals is 0. d It is reduced to half the symbol length, as shown in Figure 13. At this time, the frequency sweep range is expanded to one subcarrier interval. When m is 4 and k is 2, the spectrum diagram corresponding to the symbol is shown in Figure 14. The sampling point position of the first type of sampling point is the asymmetric position centered on the 64 frequency domain sampling points. The IFFT of the 64 frequency domain sampling points in the spectrum shown in Figure 14 is performed to obtain the time domain waveform corresponding to a symbol as shown in Figure 15. When the waveform of a symbol is as shown in Figure 15, each symbol is composed of four completely repeated data segments, and the sending time interval N between two consecutive signals is 1. d It is reduced to 1 / 4 symbol length, and the frequency sweep range is expanded to two subcarrier intervals.

[0330] It should be noted that the value of k can be 0. When the value of k is 0, the time domain waveform corresponding to one symbol obtained by performing IFFT on the 64 frequency domain sampling points in the spectrum has no repeated data, so the sending time interval N between two consecutive signals is d The length of the symbol is one, and the sweep range is half the subcarrier spacing.

[0331] To sum up, the device provided in the embodiment of the present application can make the interval between the time domain starting positions of each sub-signal in at least two sub-signals less than one time domain unit, thereby expanding the scanning range. The second device using this device does not need to perform special processing when receiving the signal, and no additional resource consumption is added to the second device.

[0332] In the above scheme, the frequency sweep range is expanded, but the final waveform is not flat in the time domain and frequency domain. The uneven waveform means that the energy will be more concentrated when the signal is sent, which is not conducive to signal transmission. Therefore, the following two schemes are proposed. It should be noted that the following two schemes can be executed simultaneously or one of them can be executed selectively.

[0333] Solution 1: time domain flattening;

[0334] Option 2: frequency domain flattening.

[0335] The following text introduces the above two implementation methods in turn, but the order of introduction of the two implementation methods does not limit the advantages and disadvantages of the two implementation methods.

[0336] Solution 1: time domain flattening.

[0337] The time domain flattening is performed on the first type of sampling points in the spectrum graph, and the data corresponding to the m first type of sampling points are determined based on at least one of the following information:

[0338] A sequence of all 1s;

[0339] ·First sequence;

[0340] A partial sequence of the first sequence;

[0341] First modulation information;

[0342] Pseudo-random ±1 sequence;

[0343] The first sequence includes at least one of a ZC sequence, a PN sequence, an m sequence, and a Gold sequence; and the first modulation information includes at least one of QPSK modulation information and QAM modulation information.

[0344] Exemplarily, when the data corresponding to the m first-type sampling points are all 1, the corresponding frequency spectrum and time-domain waveform are as shown in FIG11 and FIG12 or FIG14 and FIG15 , which are not described in detail here.

[0345] Exemplarily, the data corresponding to m first-type sampling points are determined based on a first sequence, where the first sequence is a randomized sequence, or the first sequence is a pseudo-random sequence, and the first sequence includes at least one of a ZC sequence, a PN sequence, an m sequence, and a Gold sequence. Figure 16 shows a frequency spectrum diagram where n is 64, m is 16, and k is 2, and the data corresponding to the first-type sampling points are determined based on the ZC sequence. Figure 17 is a time domain waveform diagram obtained after performing IFFT on the sampling points in the frequency spectrum diagram corresponding to Figure 16. When the data corresponding to the m first-type sampling points are determined based on a partial sequence of the first sequence, the resulting frequency spectrum diagram and time domain waveform diagram are similar to those of the first-type sampling points determined based on the first sequence, and are not further described here. The data corresponding to the first-type sampling points have a one-to-one correspondence with the sequence elements in the first sequence.

[0346] Exemplarily, the data corresponding to m first-type sampling points is determined based on first modulation information, where the first modulation information includes at least one of QPSK modulation information and QAM modulation information. Figure 18 shows a frequency spectrum where n is 64, m is 4, and k is 2, and the data corresponding to the first-type sampling points is determined based on QPSK modulation information. Figure 19 shows a time-domain waveform obtained by performing an IFFT on the sampling points in the frequency spectrum corresponding to Figure 18.

[0347] Exemplarily, the data corresponding to m first-type sampling points is determined based on a pseudo-random ±1 sequence. Figure 20 shows a spectrum diagram where n is 64, m is 4, and k is 2, and the data corresponding to the first-type sampling points is determined based on a pseudo-random ±1 sequence. Figure 21 shows a time-domain waveform diagram obtained by performing an IFFT on the sampling points in the spectrum diagram corresponding to Figure 20.

[0348] In summary, the device provided in the embodiment of the present application performs random processing on frequency domain information during the signal generation process, thereby ensuring the flatness of the time domain waveform, avoiding signal distortion and saturation of the power amplifier, and facilitating signal transmission.

[0349] Option 2: frequency domain flattening.

[0350] Frequency domain flattening can be understood as randomizing the frequency offset calibration signal during its generation. Optionally, the frequency offset calibration signal is multiplied by a random sequence to obtain a randomized frequency offset calibration signal. The random sequence includes multiple random sequence elements, each of which is at least one of the following:

[0351] Multiple random sequence elements are random.

[0352] The random sequence elements corresponding to the time domain sampling points within a time domain unit are the same, and the random sequence elements corresponding to the time domain sampling points in different time domain units are random.

[0353] The random sequence elements corresponding to the time domain sampling points within one cycle are the same, and the random sequence elements corresponding to the time domain sampling points in different cycles are random.

[0354] The random sequence elements corresponding to the time domain sampling points within a time domain unit are random, and the random sequence elements corresponding to the time domain sampling points in different time domain units are the same.

[0355] The random sequence elements corresponding to the time domain sampling points within one cycle are random, and the random sequence elements corresponding to the time domain sampling points in different cycles are the same.

[0356] In some embodiments, when the frequency offset calibration signal is multiplied by the random sequence, the i-th time domain sampling point is multiplied by the i-th random sequence element in the random sequence. For example, if there are four time domain sampling points, their corresponding data is {1, 0, 1, 0}, and the random sequence is {x1, x2, x3, x4}, the randomized result obtained after multiplication is {x1, 0, x3, 0}.

[0357] In some embodiments, after randomization processing is performed on the frequency offset calibration signal, the randomized frequency offset calibration signal is sent.

[0358] Exemplarily, the random sequence elements corresponding to the time domain sampling points of multiple random sequence elements in one time domain unit are the same, and the random sequence elements corresponding to the time domain sampling points in different time domain units are random. For example, the random sequence elements corresponding to the time domain sampling points in the first time domain unit are all 1, the random sequence elements corresponding to the time domain sampling points in the second time domain unit are all 2, and the random sequence elements corresponding to the time domain sampling points in the third time domain unit are all 3.

[0359] Exemplarily, the random sequence elements corresponding to the time domain sampling points within one period of multiple random sequence elements are random, and the random sequence elements corresponding to the time domain sampling points in different periods are the same. For example, the random sequence elements corresponding to the time domain sampling points in different periods are all "123456".

[0360] After receiving the frequency-domain flattened frequency offset calibration signal, the second device can derandomize the frequency offset calibration signal. Derandomization involves multiplying the frequency offset calibration signal by conj(random sequence). The conj() method can be used to obtain the conjugate value of the random sequence. Let the unrandomized frequency offset calibration signal be denoted as A, and the random sequence be denoted as B. The result obtained after randomizing the frequency offset calibration signal is A*B; derandomization is equivalent to A*B*conj(B). Since conj(B) is the conjugate value of B, B*conj(B) is |B| 2 , that is, the square of the random sequence modulus; thus, the frequency offset calibration signal A without randomization processing can be calculated.

[0361] In summary, the apparatus provided in the embodiment of the present application performs randomization processing during the generation of the frequency offset calibration signal, which can alleviate the problem of spectrum energy concentration and flatten the spectrum energy, thereby improving frequency selectivity and anti-interference capability.

[0362] It should be noted that the device provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0363] Regarding the device in this embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method and will not be elaborated here.

[0364] Figure 26 shows a schematic structural diagram of a wireless communication device (AP or STA) provided in some exemplary embodiments of the present application. The wireless communication device 700 includes: a processor 701, a receiver 702, a transmitter 703, a memory 704 and a bus 705.

[0365] The processor 701 includes one or more processing cores, and the processor 801 executes various functional applications and information processing by running software programs and modules.

[0366] The receiver 702 and the transmitter 703 may be implemented as a transceiver 706 , which may be a communication chip.

[0367] Memory 704 is connected to processor 701 via bus 705. Memory 704 can be used to store computer programs, and processor 701 is used to execute these computer programs to implement the various steps performed by the Ambient IoT device, terminal device, or network device in the above-described method embodiments. Transceiver 706 may include a transmitter and a receiver. The transmitter is used to implement the steps or functions related to transmission in the above-described method, the receiver is used to implement the steps or functions related to reception in the above-described method, and the processor 701 is used to implement the remaining steps or functions beyond transmission and reception.

[0368] In addition, the memory 704 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: RAM (Random-Access Memory) and ROM (Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory or other solid-state storage technology, CD-ROM (Compact Disc Read-Only Memory), DVD (Digital Video Disc) or other optical storage, tape cassettes, magnetic tape, disk storage or other magnetic storage devices.

[0369] An embodiment of the present application also provides a computer-readable storage medium, which stores a computer program. The computer program is used to be executed by a processor of an Ambient IoT device, a terminal device, or a network device to implement each step in the above-mentioned frequency offset calibration method.

[0370] In some embodiments, the computer-readable storage medium may include: ROM (Read-Only Memory), RAM (Random-Access Memory), SSD (Solid State Drives), or an optical disk, etc. Among them, the random access memory may include ReRAM (Resistance Random Access Memory) and DRAM (Dynamic Random Access Memory).

[0371] An embodiment of the present application further provides a chip, which includes a programmable logic circuit and / or program instructions. When the chip runs on a terminal or a network device, it is used to implement a frequency offset calibration method.

[0372] An embodiment of the present application also provides a computer program product or computer program, which includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the terminal or network device reads and executes the computer instructions from the computer-readable storage medium to implement the above-mentioned frequency offset calibration method.

[0373] Those skilled in the art will appreciate that in one or more of the above examples, the functions described in the embodiments of the present application can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any media that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0374] It should be understood that the frame format and element format shown in the embodiments of the present application are exemplary cases. In different embodiments or different designs, it is not ruled out that at least one of the positions of the fields in the frame / element, the arrangement order with other fields, the number of bytes occupied, and the number of bits occupied may be changed. The present application does not limit the specific format of each frame or each element.

[0375] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A frequency offset calibration method, characterized in that, The method is executed by a first device, and the method includes: Generating a frequency offset calibration signal, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration, the at least two sub-signals are respectively a part of the frequency offset calibration signal, and the at least two sub-signals are the same; Sending the frequency offset calibration signal to a second device.

2. The method according to claim 1, characterized in that, The at least two sub-signals being the same includes at least one of: having the same waveform; having the same data; having the same length; having the same phase; having the same sequence for generating the at least two sub-signals; having the same formula for generating the at least two sub-signals.

3. The method according to claim 1 or 2, characterized in that, The at least two sub-signals include a first sub-signal and a second sub-signal; The first sub-signal and the second sub-signal are two consecutive parts in the frequency offset calibration signal; or, the first sub-signal and the second sub-signal are two partially overlapping parts in the frequency offset calibration signal.

4. The method according to any one of claims 1 to 3, characterized in that, The at least two sub-signals adopt at least one of an orthogonal frequency division multiplexing (OFDM) waveform, a hybrid waveform of an OFDM waveform and an on-off keying (OOK) waveform, a triangular wave waveform, a square wave waveform, and a pulse wave waveform.

5. The method according to any one of claims 1 to 4, characterized in that, The frequency offset calibration signal is a periodic signal.

6. The method according to claim 5, characterized in that, A time domain unit includes multiple periods of the frequency offset calibration signal.

7. The method according to any one of claims 1 to 6, characterized in that, Each of the at least two sub-signals occupies multiple time domain units in the time domain; or, occupies one time domain unit in the time domain; or, the duration occupied in the time domain is not an integer multiple of one time domain unit, or the duration occupied in the time domain is less than one time domain unit.

8. The method according to any one of claims 1 to 7, characterized in that, Each of the at least two sub-signals includes in the time domain: one period or multiple periods or a part within one period of the frequency offset calibration signal.

9. The method according to any one of claims 1 to 8, characterized in that, The interval between the time domain start positions of each of the at least two sub-signals is an integer multiple of the period.

10. The method according to any one of claims 1 to 9, characterized in that, The interval between the time domain start positions of each of the at least two sub-signals is less than one time domain unit.

11. The method according to any one of claims 1 to 10, characterized in that, The frequency offset calibration signal includes n time domain sampling points in one time domain unit, and the data corresponding to the n time domain sampling points is obtained by performing an inverse Fourier transform (IFFT) on the data corresponding to n frequency domain sampling points.

12. The method according to claim 11, characterized in that, The n frequency-domain sampling points include: m first-type sampling points corresponding to non-zero data; wherein, the interval between two adjacent first-type sampling points is the same and is 2 k frequency-domain sampling intervals; Wherein, m is a positive integer greater than or equal to 2, n is a positive integer greater than or equal to m, and k is a non-negative integer.

13. The method according to claim 12, characterized in that, The sampling point positions of the m first type sampling points include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points do not include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points.

14. The method according to claim 12, characterized in that, The sampling point positions of the m first type sampling points are the central positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are non-central positions of the n frequency domain sampling points.

15. The method according to claim 12, characterized in that, The sampling point positions of the m first type sampling points are the symmetric positions of the n frequency domain sampling points; or, the sampling point positions of the m first type sampling points are asymmetric positions of the n frequency domain sampling points.

16. The method according to any one of claims 12 to 15, characterized in that, The data corresponding to the m first-type sampling points is determined based on at least one of the following information: a sequence of all 1s; a first sequence; a partial sequence of the first sequence; first modulation information; a pseudo-random ±1 sequence. Wherein, the first sequence includes at least one of a ZC sequence, a PN sequence, an m sequence, and a Gold sequence; the first modulation information includes at least one of quadrature phase shift keying (QPSK) modulation information and quadrature amplitude modulation (QAM) modulation information.

17. The method according to any one of claims 1 to 16, characterized in that, Sending the frequency offset calibration signal to the second device includes: Multiplying the frequency offset calibration signal by a random sequence to obtain a randomized frequency offset calibration signal. Sending the randomized frequency offset calibration signal.

18. The method according to claim 17, wherein The random sequence includes a plurality of random sequence elements. The plurality of random sequence elements are random; or, the random sequence elements corresponding to the time domain sampling points within one time domain unit are the same, and the random sequence elements corresponding to the time domain sampling points in different time domain units are random; or, the random sequence elements corresponding to the time domain sampling points within one period are the same, and the random sequence elements corresponding to the time domain sampling points in different periods are random; or, the random sequence elements corresponding to the time domain sampling points within one time domain unit are random, and the random sequence elements corresponding to the time domain sampling points in different time domain units are the same; or, the random sequence elements corresponding to the time domain sampling points within one period are random, and the random sequence elements corresponding to the time domain sampling points in different periods are the same. The random sequence elements corresponding to the time domain sampling points within one time domain unit are random, and the random sequence elements corresponding to the time domain sampling points in different time domain units are the same; or, the random sequence elements corresponding to the time domain sampling points within one period are random, and the random sequence elements corresponding to the time domain sampling points in different periods are the same.

19. The method according to any one of claims 1 to 18, wherein The first device is a terminal device, and the second device is a network device; or, the first device is a network device, and the second device is a terminal device.

20. The method according to claim 19, wherein The terminal device uses a resistor-capacitor (RC) oscillator or an inductor-capacitor (LC) oscillator.

21. The method according to claim 19 or 20, wherein The network device is used to calibrate a first frequency error using the at least two sub-signals. The first frequency error is an error generated when the terminal device sends an uplink signal, and the error includes at least one of an error caused by an error in the oscillator used by the terminal device and an error generated during the transmission of the uplink signal. The uplink signal includes the at least two sub-signals; or, The terminal device is used to calibrate a second frequency error using the at least two sub-signals. The second frequency error is an error generated when the terminal device receives a downlink signal, and the error includes at least one of an error caused by an error in the oscillator used by the terminal device and an error generated during the transmission of the downlink signal. The downlink signal includes the at least two sub-signals.

22. A frequency offset calibration method, wherein The method is executed by a second device, and the method includes: Receiving a frequency offset calibration signal sent by a first device. The frequency offset calibration signal includes at least two sub-signals for frequency offset calibration. The at least two sub-signals are respectively a part of the frequency offset calibration signal, and the at least two sub-signals are the same when sent.

23. The method according to claim 22, wherein The at least two sub-signals being the same includes at least one of the following: the waveforms are the same; the data is the same; the lengths are the same; the phases are the same; the sequences used to generate the at least two sub-signals are the same; the formulas used to generate the at least two sub-signals are the same.

24. The method according to claim 22 or 23, wherein The at least two sub-signals include a first sub-signal and a second sub-signal; The first sub-signal and the second sub-signal are two consecutive parts in the frequency offset calibration signal; or, the first sub-signal and the second sub-signal are two partially overlapping parts in the frequency offset calibration signal.

25. The method according to any one of claims 22 to 24, wherein The at least two sub-signals adopt at least one of a hybrid waveform of an orthogonal frequency division multiplexing (OFDM) waveform, an OFMD waveform, and an on-off keying (OOK) waveform, a triangular wave waveform, a square wave waveform, and a pulse wave waveform.

26. The method according to any one of claims 22 to 25, wherein The frequency offset calibration signal is a periodic signal.

27. The method according to claim 26, wherein A time domain unit includes multiple periods of the frequency offset calibration signal.

28. The method according to any one of claims 22 to 27, wherein Each of the at least two sub-signals occupies multiple time domain units in the time domain; or occupies one time domain unit in the time domain; or the occupied duration in the time domain is not an integer multiple of one time domain unit, or the occupied duration in the time domain is less than one time domain unit.

29. The method according to any one of claims 22 to 28, wherein Each of the at least two sub-signals includes, in the time domain: one period or multiple periods or a part within one period of the frequency offset calibration signal.

30. The method according to any one of claims 22 to 29, wherein The interval between the time domain start positions of each of the at least two sub-signals is an integer multiple of the period.

31. The method according to any one of claims 22 to 30, wherein The interval between the time domain start positions of each of the at least two sub-signals is less than one time domain unit.

32. The method according to any one of claims 22 to 31, wherein The frequency offset calibration signal includes n time domain sampling points in one time domain unit, and the data corresponding to the n time domain sampling points is obtained by performing an inverse Fourier transform (IFFT) on the data corresponding to n frequency domain sampling points.

33. The method according to claim 32, wherein The n frequency-domain sampling points include: m first-type sampling points corresponding to non-zero data; where the interval between two adjacent first-type sampling points is the same and is 2 k frequency-domain sampling intervals; Wherein, m is a positive integer greater than or equal to 2, n is a positive integer greater than or equal to m, and k is a non-negative integer.

34. The method according to claim 33, wherein, The sampling point positions of the m first type sampling points include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points; or the sampling point positions of the m first type sampling points do not include the first frequency domain sampling point and / or the last frequency domain sampling point among the n frequency domain sampling points.

35. The method according to claim 33, wherein, The sampling point positions of the m first type sampling points are the central positions of the n frequency domain sampling points; or the sampling point positions of the m first type sampling points are non-central positions of the n frequency domain sampling points.

36. The method according to claim 33, wherein, The sampling point positions of the m first type sampling points are symmetric positions of the n frequency domain sampling points; or the sampling point positions of the m first type sampling points are asymmetric positions of the n frequency domain sampling points.

37. The method according to any one of claims 32 to 36, wherein, The data corresponding to the m first type sampling points is determined based on at least one of the following information: a sequence of all 1s; a first sequence; a partial sequence of the first sequence; first modulation information; a pseudo-random ±1 sequence; Wherein, the first sequence includes at least one of a ZC sequence, a PN sequence, an m sequence, and a Gold sequence; the first modulation information includes at least one of orthogonal phase shift keying (QPSK) modulation information and orthogonal amplitude modulation (QAM) modulation information.

38. The method according to any one of claims 22 to 37, wherein, Receiving the frequency offset calibration signal sent by the first device includes: Receiving the randomized frequency offset calibration signal sent by the first device, where the randomized frequency offset calibration signal is obtained by multiplying the frequency offset calibration signal by a random sequence.

39. The method according to claim 28, wherein, The random sequence includes a plurality of random sequence elements; The plurality of random sequence elements are random; or, the random sequence elements corresponding to the time-domain sampling points within one time-domain unit are the same, and the random sequence elements corresponding to the time-domain sampling points in different time-domain units are random; or, the random sequence elements corresponding to the time-domain sampling points within one period are the same, and the random sequence elements corresponding to the time-domain sampling points in different periods are random; or, the random sequence elements corresponding to the time-domain sampling points within one time-domain unit are random, and the random sequence elements corresponding to the time-domain sampling points in different time-domain units are the same; or, the random sequence elements corresponding to the time-domain sampling points within one period are random, and the random sequence elements corresponding to the time-domain sampling points in different periods are the same.

40. The method according to any one of claims 22 to 39, wherein, The method further includes: Performing frequency offset calibration based on the frequency offset calibration signal.

41. The method according to any one of claims 22 to 39, wherein, The first device is a terminal device, and the second device is a network device; or, the first device is a network device, and the second device is a terminal device.

42. The method according to claim 41, wherein, The terminal device uses a resistor-capacitor (RC) oscillator or an inductor-capacitor (LC) oscillator.

43. The method according to any one of claims 40 to 42, wherein, The performing frequency offset calibration based on the frequency offset calibration signal includes: The network device uses the at least two sub-signals to calibrate a first frequency error, where the first frequency error is an error generated when the terminal device transmits an uplink signal, and the error includes at least one of an error caused by an error in the oscillator used by the terminal device and an error generated during the transmission of the uplink signal. The uplink signal includes the at least two sub-signals; or, The terminal device uses the at least two sub-signals to calibrate a second frequency error, where the second frequency error is an error generated when the terminal device receives a downlink signal, and the error includes at least one of an error caused by an error in the oscillator used by the terminal device and an error generated during the transmission of the downlink signal. The downlink signal includes the at least two sub-signals.

44. A frequency offset calibration device, wherein, The apparatus includes: A generating module, configured to generate a frequency offset calibration signal, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration. The at least two sub-signals are respectively a part of the frequency offset calibration signal, and the at least two sub-signals are the same; A sending module, configured to send the frequency offset calibration signal to a second device.

45. A frequency offset calibration device, wherein, The apparatus includes: A receiving module, configured to receive a frequency offset calibration signal sent by a first device, where the frequency offset calibration signal includes at least two sub-signals for frequency offset calibration. The at least two sub-signals are respectively a part of the frequency offset calibration signal, and the at least two sub-signals are the same when being sent.

46. A computer-readable storage medium, wherein, A computer program is stored in the computer-readable storage medium, and the computer program is used to be executed by a processor to implement the frequency offset calibration method according to any one of claims 1 to 21, or, the frequency offset calibration method according to any one of claims 22 to 43.

47. A chip, wherein, The chip includes programmable logic circuits and / or program instructions, which are used to implement the frequency offset calibration method according to any one of claims 1 to 21, or the frequency offset calibration method according to any one of claims 22 to 43 when the chip runs.

48. A computer program product or computer program, wherein, The computer program product or computer program includes computer instructions stored in a computer-readable storage medium. The processor reads and executes the computer instructions from the computer-readable storage medium to implement the frequency offset calibration method according to any one of claims 1 to 21, or the frequency offset calibration method according to any one of claims 22 to 43.

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