Communication method and apparatus

Abstract

The application provides a communication method and device, belonging to the technical field of communication, to ensure the synchronization performance of the device in the sleep state. The method comprises: a first device determines a first signal and transmits the first signal. Since the first signal comprises a first synchronization signal and N reference frequency signals, each reference frequency signal is a single frequency signal. In this case, if the demodulation is based on the local crystal oscillator, each reference frequency signal can generate a frequency offset similar to the first synchronization signal, thereby eliminating the frequency offset of the first synchronization signal. In this way, the device uses the synchronization signal without frequency offset for correlation operation, can accurately determine the time domain position of the correlation peak, complete device synchronization, and ensure the synchronization performance of the device in the sleep state. The application scheme can be widely applied to the fields of communication technology, artificial intelligence, Internet of Vehicles, smart home networking and the like.

Description

[0001] This application claims priority to Chinese Patent Application No. 202111480752.9, filed with the State Intellectual Property Office of China on December 6, 2021, entitled "A Synchronization Method for Wake-up Signals", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more particularly to a communication method and apparatus. Background Technology

[0003] In New Radio (NR) systems, when there is no data service, the terminal can enter a sleep state, such as idle, to reduce power consumption and save energy. During this time, the terminal and base station can exchange signals via the wake-up radio (WUR) link. For example, the base station can send a synchronization signal to the terminal via the WUR link to achieve synchronization between the two. Subsequently, when data service is available, the base station can send a wake-up signal to the terminal via the WUR link to instruct the terminal to resume operation from sleep mode, such as connected mode, thereby enabling data transmission and reception.

[0004] It's understandable that terminals need to maintain low power consumption in sleep mode, and their demodulation of synchronization signals typically uses a low-power local crystal oscillator. However, the performance of local crystal oscillators is limited, and the demodulated signal usually has a frequency offset. When the terminal uses the frequency-offset signal to perform correlation operations, it is difficult to determine the time-domain location of the correlation peak, making it impossible to complete device synchronization and affecting the synchronization performance of the terminal in sleep mode. Summary of the Invention

[0005] This application provides a communication method and apparatus to ensure the synchronization performance of a device in a sleep state.

[0006] The technical solution adopted in this application is as follows:

[0007] Firstly, a communication method is provided. The method includes: a first device determining a first signal and transmitting the first signal. The first signal is carried on a first time-frequency resource, and includes: a first synchronization signal and N reference frequency signals, where N is a positive integer. The first synchronization signal and the N reference frequency signals have different time-domain positions, and each of the N reference frequency signals is a single-frequency signal.

[0008] As described in the first aspect, the first signal includes a first synchronization signal and N reference frequency signals, each reference frequency signal being a single-frequency signal. In this case, if demodulation is performed based on a local crystal oscillator, each reference frequency signal can generate a frequency offset similar to that of the first synchronization signal, thereby eliminating the frequency offset of the first synchronization signal. Thus, the device can accurately determine the time-domain position of the correlation peak using the frequency-offset-free synchronization signal, completing device synchronization and ensuring the synchronization performance of the device in sleep mode.

[0009] In one possible design, at least two of the N reference frequency signals are located at different frequency domain positions, such as continuous or discontinuous frequency domain positions, meaning the frequencies of these at least two reference frequency signals are different. Typically, the frequency response of a wireless channel is not always flat and fluctuates with environmental changes. If a frequency experiences fading, such as deep fading, it is difficult to eliminate the frequency offset of the first synchronization signal using the reference frequency signal at that deeply faded frequency. This makes it difficult to determine the time domain position of the correlation peak, and consequently, it is impossible to guarantee the synchronization performance of the device in sleep mode. However, since the at least two reference frequency signals are located at different frequencies, the probability of both frequencies experiencing deep fading is relatively low. As long as one frequency does not experience deep fading, the frequency offset of the reference frequency signal at that non-deeply faded frequency can be used to eliminate the frequency offset of the first synchronization signal, completing device synchronization and further ensuring the synchronization performance of the device in sleep mode. This is the so-called frequency diversity gain. Taking two reference frequency signals as an example, reference frequency signal 1 is located at frequency 1, and reference frequency signal 2 is located at frequency 2. If frequency 1 experiences deep fading, the frequency offset of the reference frequency signal 2 at frequency 2 can be used to eliminate the frequency offset of the first synchronization signal, thus completing device synchronization. Similarly, if frequency 2 experiences deep fading, the frequency offset of the reference frequency signal 1 at frequency 1 can be used to eliminate the frequency offset of the first synchronization signal, thus completing device synchronization.

[0010] Optionally, at least two of the N reference frequency signals are located at the same time domain position. This saves time domain resources and improves resource utilization and communication efficiency. These at least two reference frequency signals generate a frequency offset closer to the first synchronization signal, thereby minimizing the frequency offset of the first synchronization signal and further ensuring the synchronization performance of the device in sleep mode. Alternatively, at least two of the N reference frequency signals are located at different time domain positions. In this way, during demodulation, the device can receive each reference frequency signal individually, avoiding interference from other reference frequency signals, thereby minimizing the frequency offset of the first synchronization signal and further ensuring the synchronization performance of the device in sleep mode.

[0011] Furthermore, at least two of the N reference frequency signals are located in consecutive time-domain positions. For example, some of the N reference frequency signals are located in consecutive time-domain positions, while others are located in discontinuous time-domain positions, meaning there are time-domain intervals between them. Alternatively, the N reference frequency signals may be located in consecutive time-domain positions, meaning that the time-domain positions of any two adjacent reference frequency signals are consecutive. Thus, transmitting at consecutive time-delay positions can ensure that these at least two reference frequency signals generate more similar frequency offsets during demodulation, thereby minimizing the frequency offset of the first synchronization signal and ensuring the synchronization performance of the device in sleep mode.

[0012] In one possible design scheme, the i-th reference frequency signal among the N reference frequency signals is: i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let f be the duration of the i-th reference frequency signal. That is, the i-th reference frequency signal has a frequency of f. i A single-frequency signal is used to facilitate subsequent frequency offset elimination.

[0013] In one possible design, after the first device sends the first signal, the method described in the first aspect further includes: the first device sending a wake-up signal, wherein the data in the wake-up signal is carried based on a combination of the on or off states of resource units in a resource unit set, the resource unit set belonging to a first time-frequency resource. It can be understood that carrying data based on a combination of the on or off states of resource units enables resource reuse, thereby improving communication efficiency and spectrum efficiency.

[0014] Optionally, a resource element occupies at least one orthogonal frequency division multiplexing (OFDM) symbol in time and at least one OFDM subcarrier in frequency. In other words, the granularity of the resource element can be selectively chosen based on the specific scenario; for example, it can be a resource element (RE) or a resource block (RB) to ensure its applicability to the actual scenario.

[0015] Secondly, a communication method is provided. The method includes: a second device receiving a first signal and parsing the first signal. The first signal is carried on a first time-frequency resource and includes: a first synchronization signal and N reference frequency signals, where N is an integer. The first synchronization signal and the N reference frequency signals have different time-domain positions, and each of the N reference frequency signals is a single-frequency signal.

[0016] In one possible design, at least two of the N reference frequency signals are located at different frequency domain positions.

[0017] Optionally, at least two of the N reference frequency signals are located at the same time domain position. Alternatively, at least two of the N reference frequency signals are located at different time domain positions.

[0018] Furthermore, at least two of the N reference frequency signals are located in consecutive time domain positions.

[0019] In one possible design scheme, the i-th reference frequency signal among the N reference frequency signals is: i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let be the duration of the i-th reference frequency signal.

[0020] In one possible design, the second device analyzes the first signal, including: demodulating the first signal to obtain a synchronization sequence with frequency offset and N reference frequency sequences with frequency offset. Then, the second device determines the time-domain position of the correlation peak based on the synchronization sequence with frequency offset, the N reference frequency sequences with frequency offset, the first synchronization sequence, and the N reference frequency sequences. For example, the second device can first eliminate the frequency offset based on the synchronization sequence with frequency offset and the N reference frequency sequences, and then accurately determine the time-domain position of the correlation peak based on the first synchronization sequence and the N reference frequency sequences. The synchronization sequence with frequency offset is the sequence obtained after down-converting and sampling the first synchronization signal. The i-th reference frequency sequence with frequency offset among the N reference frequency sequences is the sequence obtained after down-converting and sampling the i-th reference frequency signal among the N reference frequency signals, where i is any integer from 1 to N. The first synchronization sequence is used to modulate the first synchronization signal, and the N reference frequency sequences are used to modulate the N reference frequency signals.

[0021] Optionally, the second device determines the time-domain position of the correlation peak based on the frequency-biased synchronization sequence, N frequency-biased reference frequency sequences, the first synchronization sequence, and the N reference frequency sequences. This includes: the second device multiplies the frequency-biased synchronization sequence with the conjugate transpose of the i-th frequency-biased reference frequency sequence to obtain the i-th conjugate transpose sequence, and then performs correlation operations on the i-th conjugate transpose sequence, the first synchronization sequence, and the i-th reference frequency sequence to determine the time-domain position of the correlation peak.

[0022] It should be noted that conjugate transpose multiplication can be: the sequence obtained by multiplying the frequency-biased synchronization sequence by the conjugate of the i-th frequency-biased reference frequency sequence, or the sequence obtained by multiplying the frequency-biased reference frequency sequence by the conjugate of the frequency-biased synchronization sequence. For example, the first synchronization sequence is represented as s. sync (n), the i-th reference frequency sequence is represented as f i f is the frequency of the i-th reference frequency sequence. s Let f be the sampling frequency of the analog-to-digital converter. The frequency offset generated by the first synchronization sequence and the i-th reference frequency sequence during demodulation is denoted as f. offset Therefore, a synchronization sequence with frequency offset is represented as follows: The conjugate sequence of the i-th reference frequency sequence with frequency offset is represented as follows: Based on this, the conjugate transpose multiplication is expressed as: This eliminates the influence of frequency offset, ensuring that the time-domain location of the relevant peak can be accurately determined subsequently. Furthermore, since the conjugate transpose multiplication has no limitation on the magnitude of the frequency offset, even large frequency offsets can be eliminated.

[0023] In one possible design, after the second device receives the first signal, the method described in the second aspect further includes: the second device receiving a wake-up signal, wherein the data in the wake-up signal is carried based on a combination of the on or off states of resource units in a resource unit set, and the resource unit set belongs to a first time-frequency resource.

[0024] Optionally, a resource element occupies at least one OFDM symbol in time and at least one carrier in frequency.

[0025] It is understood that other technical effects of the method described in the second aspect can be referred to the technical effects of the method described in the first aspect, and will not be repeated here.

[0026] Thirdly, a communication apparatus is provided. The apparatus includes modules for performing the method described in the first aspect. For example, it includes a transceiver module and a processing module. The processing module is used to determine a first signal; the transceiver module is used to transmit the first signal. The first signal is carried on a first time-frequency resource and includes a first synchronization signal and N reference frequency signals, where N is a positive integer. The first synchronization signal and the N reference frequency signals have different time-domain positions, and each of the N reference frequency signals is a single-frequency signal.

[0027] In one possible design, at least two of the N reference frequency signals are located at different frequency domain positions.

[0028] Optionally, at least two of the N reference frequency signals are located at the same time domain position.

[0029] Alternatively, at least two of the N reference frequency signals are located at different time domain positions.

[0030] Furthermore, at least two of the N reference frequency signals are located in consecutive time domain positions.

[0031] In one possible design scheme, the i-th reference frequency signal among the N reference frequency signals is: i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let be the duration of the i-th reference frequency signal.

[0032] In one possible design, the transceiver module is further configured to send a wake-up signal after sending the first signal. The data in the wake-up signal is carried as a combination of the on or off states of resource units in a resource unit set, where the resource unit set belongs to the first time-frequency resource.

[0033] Optionally, the resource element occupies at least one orthogonal frequency division multiplexing (OFDM) symbol in time and at least one OFDM subcarrier in frequency.

[0034] Optionally, the transceiver module may also include a sending module and a receiving module. The sending module implements the sending function of the device described in the third aspect, and the receiving module implements the receiving function of the device described in the third aspect.

[0035] Optionally, the apparatus described in the third aspect may further include a storage module storing a program or instructions. When the processing module executes the program or instructions, the apparatus can perform the method described in the first aspect.

[0036] It should be noted that the device described in the third aspect may be a terminal or network device, or a chip (system) or other component or assembly that can be configured in the terminal or network device, or a device that includes the terminal or network device. This application does not limit this.

[0037] Furthermore, the technical effects of the device described in the third aspect can be referred to the technical effects of the method described in the first aspect, and will not be repeated here.

[0038] Fourthly, a communication device is provided. The device includes a module for performing the method described in the second aspect. For example, it includes a transceiver module and a processing module. The transceiver module is used to receive a first signal; the processing module is used to parse the first signal. The first signal is carried on a first time-frequency resource and includes a first synchronization signal and N reference frequency signals, where N is an integer. The first synchronization signal and the N reference frequency signals have different time-domain positions, and each of the N reference frequency signals is a single-frequency signal.

[0039] In one possible design, at least two of the N reference frequency signals are located at different frequency domain positions.

[0040] Optionally, at least two of the N reference frequency signals are located at the same time domain position. Alternatively, at least two of the N reference frequency signals are located at different time domain positions.

[0041] Furthermore, at least two of the N reference frequency signals are located in consecutive time domain positions.

[0042] In one possible design scheme, the i-th reference frequency signal among the N reference frequency signals is: i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let be the duration of the i-th reference frequency signal.

[0043] In one possible design, the processing module is further configured to demodulate the first signal to obtain a synchronization sequence with frequency offset and N reference frequency sequences with frequency offset, and to determine the time-domain position of the correlation peak based on the synchronization sequence with frequency offset, the N reference frequency sequences with frequency offset, the first synchronization sequence, and the N reference frequency sequences. Here, the synchronization sequence with frequency offset is the sequence obtained by demodulating the first synchronization signal, and the i-th reference frequency sequence with frequency offset among the N reference frequency sequences is the sequence obtained by demodulating the i-th reference frequency signal among the N reference frequency signals, where i is any integer from 1 to N. The first synchronization sequence is used to modulate the first synchronization signal, and the N reference frequency sequences are used to modulate the N reference frequency signals.

[0044] Optionally, the processing module is further configured to multiply the synchronization sequence with frequency offset by the conjugate transpose of the i-th reference frequency sequence with frequency offset to obtain the i-th conjugate transpose sequence, and perform correlation operations on the i-th conjugate transpose sequence, the first synchronization sequence, and the i-th reference frequency sequence to determine the time domain position of the correlation peak.

[0045] In one possible design, the transceiver module is further configured to receive a wake-up signal after receiving the first signal. The data in the wake-up signal is carried as a combination of the on or off states of resource units in a resource unit set, where the resource unit set belongs to the first time-frequency resource.

[0046] Optionally, a resource element occupies at least one OFDM symbol in time and at least one carrier in frequency.

[0047] Optionally, the transceiver module may also include a transmitting module and a receiving module. The transmitting module implements the transmitting function of the device described in the fourth aspect, and the receiving module implements the receiving function of the device described in the fourth aspect.

[0048] Optionally, the apparatus described in the fourth aspect may further include a storage module storing a program or instructions. When the processing module executes the program or instructions, the apparatus can perform the method described in the second aspect.

[0049] It should be noted that the device described in the fourth aspect may be a terminal or network device, or a chip (system) or other component or assembly that can be configured in the terminal or network device, or a device that includes a terminal or network device. This application does not limit this.

[0050] Furthermore, the technical effects of the device described in the fourth aspect can be referred to the technical effects of the method described in the second aspect, and will not be repeated here.

[0051] Fifthly, a communication device is provided. The device includes a processor, which is configured to perform the method described in the first or second aspect.

[0052] In one possible design, the device described in the fifth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the device and other devices.

[0053] In one possible design, the apparatus described in the fifth aspect may further include a memory. This memory may be integrated with the processor or disposed separately. The memory may be used to store computer programs and / or data involved in the methods described in the first or second aspect.

[0054] In this application, the apparatus described in the fifth aspect may be a terminal or network device as described in the first or second aspect, such as the first device or the second device, or may be a chip (system) or other component or assembly disposed in the terminal or network device, or may include the apparatus of the terminal or network device.

[0055] Furthermore, the technical effects of the device described in the fifth aspect can be referred to the technical effects of the method described in the first or second aspect, and will not be repeated here.

[0056] A sixth aspect provides a communication device. The device includes a processor and a memory. The memory stores computer instructions that, when executed by the processor, cause the device to perform the method described in the first or second aspect.

[0057] In one possible design, the device described in the sixth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver can be used for communication between the device and other devices.

[0058] In this application, the apparatus described in the sixth aspect may be a terminal or network device in the first or second aspect, such as the first device or the second device, or may be a chip (system) or other component or assembly disposed in the terminal or network device, or may include the apparatus of the terminal or network device.

[0059] Furthermore, the technical effects of the device described in the sixth aspect can be referred to the technical effects of the method described in the first or second aspect, and will not be repeated here.

[0060] A seventh aspect provides a communication device. The device includes: a logic circuit and an input / output interface. The input / output interface is used to receive code instructions and transmit them to the logic circuit. The logic circuit is used to execute the code instructions to perform the method described in the first or second aspect.

[0061] In this application, the apparatus described in the seventh aspect may be a terminal or network device in the first or second aspect, such as the first device or the second device, or may be a chip (system) or other component or assembly disposed in the terminal or network device, or may include the apparatus of the terminal or network device.

[0062] Furthermore, the technical effects of the device described in the seventh aspect can be referred to the technical effects of the method described in the first or second aspect, and will not be repeated here.

[0063] Eighthly, a communication device is provided. The device includes a processor and a transceiver. The transceiver is used for information exchange between the communication device and other devices, and the processor executes program instructions to perform the method described in the first or second aspect.

[0064] In one possible design, the apparatus described in the eighth aspect may further include a memory. This memory may be integrated with the processor or disposed separately. The memory may be used to store computer programs and / or data involved in the methods described in the first or second aspect.

[0065] In this application, the apparatus described in the eighth aspect may be a terminal or network device in the first or second aspect, such as the first device or the second device, or may be a chip (system) or other component or assembly disposed in the terminal or network device, or may include the apparatus of the terminal or network device.

[0066] Furthermore, the technical effects of the device described in the eighth aspect can be referred to the technical effects of the method described in the first or second aspect, and will not be repeated here.

[0067] A ninth aspect provides a communication system. The communication system includes one or more first devices and one or more second devices. The first devices are configured to perform the method as described in the first aspect, and the second devices are configured to perform the method as described in the second aspect.

[0068] A tenth aspect provides a computer-readable storage medium comprising: a computer program or instructions; wherein, when the computer program or instructions are executed on a computer, the computer causes the computer to perform the method described in the first aspect or the second aspect.

[0069] Eleventhly, a computer program product is provided, comprising a computer program or instructions that, when executed on a computer, cause the computer to perform the method described in the first or second aspect. Attached Figure Description

[0070] Figure 1 A schematic diagram of resource distribution for OFDM modulation;

[0071] Figure 2 A schematic diagram of the transmission and reception process for OFDM modulation;

[0072] Figure 3 This is a schematic diagram of the receiver architecture;

[0073] Figure 4 A schematic diagram of the architecture for the wake-up link;

[0074] Figure 5 This is a schematic diagram illustrating the temporal positional relationship between the synchronization signal and the data signal.

[0075] Figure 6 Waveform diagram of the relevant peak Figure 1 ;

[0076] Figure 7 Waveform diagram of the relevant peak Figure 2 ;

[0077] Figure 8 This application provides a schematic diagram of the architecture of a communication system.

[0078] Figure 9A flowchart illustrating a communication method provided in an embodiment of this application;

[0079] Figure 10 This is a schematic diagram illustrating the time-domain positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 1 ;

[0080] Figure 11 This is a schematic diagram illustrating the time-frequency positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 1 ;

[0081] Figure 12 This is a schematic diagram illustrating the time-frequency positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 2 ;

[0082] Figure 13 This is a schematic diagram illustrating the time-domain positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 2 ;

[0083] Figure 14 This is a schematic diagram illustrating the time-frequency positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 3 ;

[0084] Figure 15 This is a schematic diagram illustrating the time-domain positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 3 ;

[0085] Figure 16 This is a schematic diagram illustrating the time-frequency positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 4 ;

[0086] Figure 17 This is a schematic diagram illustrating the time-domain positional relationship between the synchronization signal and the reference frequency signal in the embodiments of this application. Figure 5 ;

[0087] Figure 18 This is a schematic diagram of the time-frequency domain distribution of the resource unit set in the embodiments of this application;

[0088] Figure 19 A schematic diagram of the structure of a communication device provided in this application embodiment. Figure 1 ;

[0089] Figure 20 A schematic diagram of the structure of a communication device provided in this application embodiment. Figure 2 ;

[0090] Figure 21 A schematic diagram of the structure of a communication device provided in this application embodiment. Figure 3 . Detailed Implementation

[0091] For ease of understanding, the technical terms involved in the embodiments of this application will be introduced below.

[0092] 1. Orthogonal Frequency Division Multiplexing (OFDM)

[0093] OFDM is a modulation method widely used in modern communication systems, such as LTE or NR systems.

[0094] Please see Figure 1 , Figure 1 This illustrates the time-frequency resource partitioning of OFDM modulation, which divides the system's time-frequency resources into a two-dimensional time-frequency grid. In the frequency domain, the frequency domain resources (or system bandwidth) are divided into multiple parallel subcarriers at the subcarrier granularity, for example... Figure 1 The diagram shows 512 subcarriers (including subcarrier 0 through subcarrier 511). In the time domain, the time-domain resources are divided into multiple consecutive symbols at the symbol level, for example... Figure 1 Eight symbols are shown (including symbols 0-7). A time-frequency resource with a duration of one symbol and a frequency width of one subcarrier is called a resource element (RE), for example... Figure 1 One square in the array represents a RE. Each RE can be used to carry an OFDM modulated signal to enable data transmission and reception.

[0095] Please see Figure 2 , Figure 2The transmission and reception processes of OFDM modulation are illustrated. The transmitter first maps the bit stream to be transmitted onto symbols through modulation. Common modulation techniques include: binary phase shift keying (BPSK), pi / 2-BPSK, quadrature phase shift keying (QPSK), pi / 4QPSK, 8-phase shift keying (PSK), 16PSK, quadrature amplitude modulation (QAM), 16QAM, or 64QAM, etc. Afterwards, the transmitter uses serial-to-parallel conversion (SIPO / PISO, S / P) to map each modulation symbol onto its corresponding subcarrier, and then converts the data on each subcarrier into a time-domain signal using inverse fast fourier transform (IFFT). Finally, the transmitter adds a cyclic prefix (CP) to the time-domain signal, and then performs parallel-to-serial conversion (PISO / SIPO, P / S), digital-to-analog conversion (DA), and up-conversion before transmitting the corresponding signal into the channel. Because the signal is subject to interference during air interface transmission, the receiver will receive the interfered signal. During down-conversion, the receiver will also experience frequency offset due to the deviation of the local crystal oscillator. The receiver can perform analog-to-digital conversion and correct carrier frequency offset (CFO) processing on this interfered and frequency-off signal. Afterward, the receiver can sequentially perform parallel-to-serial conversion, cyclic prefix removal, and fast Fourier transform (FFT) processing on the interference-filtered signal to obtain the frequency-domain signal. Finally, the receiver performs digital signal processing on the frequency-domain signal, including phase tracking, serial-to-parallel conversion, demodulation, and decoding, to obtain the transmitted data.

[0096] It should be noted that the receiver and transmitter mentioned above are relative concepts. A device can function as either a receiver or a transmitter, or it can function as both. This application does not make any specific limitations on this.

[0097] 2. Terminal status

[0098] In mobile communications, power saving (or energy efficiency) is one of the important goals that terminals need to achieve. For some types of terminals, such as mobile phones or wearable devices, battery life can significantly impact the user experience. For other types of terminals, such as wireless industrial sensors, due to the difficulty of replacing batteries, the design aims to enable these terminals to operate for several years without battery replacement.

[0099] To achieve this goal, the current approach is to allow the terminal to operate in different states (or modes) according to different business needs, such as connected, idle, and inactive, in order to save power. For example, when the terminal has business and needs to send and receive data, it can operate in connected mode. In this state, the terminal can exchange signaling with network devices and send and receive data. In connected mode, the terminal's power consumption is relatively high, which is not conducive to energy saving. When the terminal has no business and does not need to send or receive data, it can operate in idle or inactive mode. In this state, the terminal puts the circuit into a sleep state, periodically waking up to check if there is any data to be sent. If there is data, it enters connected mode; otherwise, it remains in idle or inactive mode and continues to sleep. In idle or inactive mode, the terminal's power consumption is much lower than in connected mode. Typically, the terminal spends more time in idle or inactive mode. For example, if a user uses their mobile phone for 4 hours a day, the phone is in connected mode for 4 hours. For the remaining 20 hours, the phone is in idle or inactive mode. Therefore, the power consumption of a terminal in idle or inactive state will largely determine its battery life and whether it can achieve energy saving.

[0100] 3. Main link and wake-up link

[0101] To minimize power consumption in idle or inactive states, a novel receiver architecture has garnered significant attention in recent years. (See also...) Figure 3 , Figure 3 The receiver architecture shown is an example of a terminal, in which the terminal is divided into a main radio and a wake-up radio (WUR), also known as the wake-up link.

[0102] The aforementioned main link, also known as the main circuit, main receiver, or main module, can be understood as the link used by the terminal when normally sending and receiving data, or the link used by the terminal when transmitting data in a connected state. It consumes a significant amount of power. Signals sent and received by the terminal using the main link can be described as being transmitted on the main link. It represents a connection relationship between the terminal and other devices, such as network devices or other terminals; it is a logical concept, not a physical entity. It is understood that "main link" is merely an exemplary designation, and its specific naming does not limit the scope of protection of this application. For example, without loss of generality, the main link can also be described as the first link. The first link can also be replaced by the first circuit, first state, first mode, first module, etc. For ease of understanding, it will be uniformly described as the main link below.

[0103] The aforementioned wake-up link, also known as a wake-up circuit, wake-up receiver, or wake-up module, can be understood as a link used by the terminal in the idle or inactive state, or as a single low-power circuit. This low-power circuit can be implemented using a simple, single circuit or chip with low power consumption. It is understood that the term "wake-up link" is merely a designation for differentiation and does not limit the scope of protection of this application. For example, without loss of generality, a wake-up link can also be described as a second link. A second link can also be replaced with a second circuit, second state, second mode, second module, etc. For ease of understanding, it will be uniformly described as a wake-up link below.

[0104] Signals transmitted and received by a terminal using the wake-up link can be described as being transmitted on the wake-up link. This represents a connection between the terminal and other devices, such as network devices or other terminals; it is a logical concept, not a physical entity. Signals transmitted and received by a terminal using the wake-up link can be called wake-up signals / radio (WUS / WUR). For ease of understanding, the WUR signal will be used as an example below. The WUR signal can include paging-related signals, such as wake-up signals, and can also include synchronization signals. The wake-up signal is at least used to indicate paging-related information (such as information indicating which terminal needs to receive it). Receiving WUR signals (such as wake-up signals) using the wake-up link can be understood as working on the wake-up link, receiving wake-up signals on the wake-up link, or receiving wake-up signals under the first link, etc. For example, when the terminal has no service and is in an idle or inactive state, the main link is closed, while the wake-up link is open. At this time, power consumption is very low, achieving a power-saving effect. When a network device needs to send a service to a terminal, it needs to send a wake-up signal to the wake-up link. When the terminal receives the wake-up signal based on the wake-up link, it will trigger the terminal to start the main link, enter the connected state, and then perform normal data transmission and reception.

[0105] Please see Figure 4 , Figure 4 It shows Figure 3 This describes a specific architecture for the wake-up link in a terminal. Taking a synchronization signal as an example, after receiving the synchronization signal, the terminal first performs radio frequency filtering on the synchronization signal based on a radio frequency filter, and then amplifies the filtered synchronization signal based on a low-noise amplifier to obtain an amplified synchronization signal. Afterwards, the terminal can use a mixer (…) Figure 4 As shown in the diagram, the amplified synchronization signal is down-converted using the local oscillator signal generated by the local crystal oscillator. Then, based on a baseband filter and an analog-to-digital converter (ADC), the down-converted synchronization signal is converted from analog to digital to obtain a digital synchronization signal. Finally, the terminal performs digital signal processing on the digital synchronization signal to achieve synchronization with other devices, such as network devices or other terminals, based on the processing results. The specific process of digital signal processing for the digital synchronization signal by the terminal can be understood by referring to the relevant introduction in "1. OFDM" above, and will not be repeated here.

[0106] It should be noted that the process of down-converting the amplified synchronization signal using a mixer in the aforementioned terminal can be as follows: the terminal uses a mixer to multiply the amplified synchronization signal with the signal generated by the local oscillator (LO) to achieve down-conversion. In a specific example, assume the baseband signal expression is s wur (t), during actual transmission, network devices or other terminals will modulate the baseband signal onto a certain high-frequency carrier frequency. For example, this carrier frequency can be represented as... f c Let t be the carrier frequency (e.g., 3 GHz) and t be time. Accordingly, the terminal can use a mixer to multiply the single-frequency signal generated by the local crystal oscillator with this carrier frequency to recover the high-frequency carrier frequency into a baseband signal, thus achieving down-conversion. For example, the frequency of this single-frequency signal corresponding to this carrier frequency can be expressed as: The multiplication operation performed by the mixer can be represented as: This indicates that in the equivalent mixing model of a complex signal, the multiplication operation performed by the mixer is multiplication by the conjugate signal. From this formula, it can be seen that the single-frequency signal generated by the local crystal oscillator of the terminal must be the same as the carrier frequency used for frequency modulation by the network equipment to ensure that the correct baseband signal is demodulated.

[0107] However, the synchronization signal sent to the terminal by network devices via modulation has a high carrier frequency, requiring a high-performance local crystal oscillator and mixer to generate the same single-frequency signal for correct demodulation. However, high-performance local crystal oscillators and mixers consume significant power. To achieve low power consumption in the wake-up link, low-power devices are often used. These low-power devices have poor performance specifications. For example, a low-power local crystal oscillator will generate a single-frequency signal with a significant frequency offset (hereinafter referred to as frequency deviation), meaning there is a deviation between the actual frequency of the generated single-frequency signal and the required frequency. For example, the local crystal oscillator needs to generate a frequency of f... c A single-frequency signal can be represented as However, due to performance deviations, the local crystal oscillator actually generates a frequency of f. c +f offset , can be represented as In this case, the baseband signal obtained based on down-conversion is not an ideal baseband signal, but a baseband signal with frequency offset, for example, represented as... The residual frequency offset of the baseband signal can have a serious impact on synchronization, which will be explained in detail below.

[0108] 4. Synchronization

[0109] In a communication system, the receiving and receiving parties must first achieve time synchronization to complete the transmission and reception process. Synchronization refers to the receiver finding the boundaries of the received signal. Taking an OFDM system as an example, the receiver, such as a terminal, needs to find the start and end positions of each symbol in the received signal. To help the terminal find the signal boundaries and achieve synchronization, transmitters, such as network devices or other terminals, typically send synchronization signals. These synchronization signals are generally designed as signals based on signal sequence modulation. This signal sequence is usually a sequence with good autocorrelation properties, also known as a synchronization sequence. The terminal can pre-store this synchronization sequence locally and use the local synchronization sequence to perform a sliding correlation with the received signal. When, at a certain moment, the synchronization sequence in the received signal aligns with the local synchronization sequence, a significant correlation peak will appear, thus determining that this moment is the point at which the transmitting and receiving parties are aligned, thereby completing device synchronization. For easier understanding, the following will combine... Figure 5 The synchronization process of the terminal is described in detail.

[0110] in, Figure 5 The temporal positional relationship between the synchronization signal and the data signal is shown, such as... Figure 5 As shown, the signal sequence of the synchronization signal is s. sync (n), 0 <n≤N sym N symThis represents the number of sampling points of the analog-to-digital converter in the terminal. Since the terminal does not know the exact location of the synchronization sequence beforehand, it can use a sampling point of length N. sym A sliding window with 100 sampling points performs sliding correlation on the received signal. Sliding correlation refers to the terminal performing a truncation operation on the sampled sequence based on the sliding window, and then performing correlation operations on the truncation signal to adjust the sliding window along the sampling window. Figure 5 The slider moves one sampling point in the direction of the middle arrow before performing the next truncation and correlation operation. Each truncation operation of the sliding window refers to extracting N samples from the corresponding position in the signal. sym With n sampling points, the sampled sequence can be represented as r(n). Taking the l-th sliding motion as an example, the sampled sequence can be represented as r l (n) = r(l+n), where l is a positive integer. The terminal can perform correlation operations on the sequence obtained by the l-th sliding cut and the synchronization sequence pre-stored locally, such as performing conjugate multiplication and summation. The resulting correlation value can be expressed as: When r slides to align with the synchronization sequence for the lth time... l (n) is s sync (n), the relevant value can be expressed as This means the correlation value reaches its maximum value. On the waveform, this maximum correlation value is represented by a significant correlation peak, for example... Figure 6 As shown, the time domain position of the correlation peak is the alignment position, or the alignment time.

[0111] As mentioned earlier, the wake-up link uses a low-power local crystal oscillator, resulting in a residual frequency offset in the sampled sequence, which can be expressed as follows: The presence of frequency offset can severely impact correlation results. For example, a correlation sequence may exhibit good autocorrelation characteristics, meaning that correlation between the same sequence and other sequences will yield a correlation peak. However, in the presence of frequency offset, the autocorrelation characteristics are disrupted when a frequency-biased sequence correlates with the same sequence, resulting in no obvious correlation peak. For an example using an OFDM system, please refer to [link to relevant documentation]. Figure 7 , Figure 7 The diagram shows the correlation peak height of an OFDM system under different frequency offsets. It can be seen that the correlation peak height decreases with increasing frequency offset. When the frequency offset exceeds the subcarrier spacing (e.g., 15 kHz), the correlation peak disappears completely. Due to the poor performance of low-power local crystal oscillators, the frequency offset they generate often exceeds the subcarrier spacing, making it difficult for the terminal to determine the time-domain location of the correlation peak, thus hindering device synchronization and affecting the terminal's synchronization performance in sleep mode.

[0112] In summary, in view of the above-mentioned technical problems, the embodiments of this application propose the following technical solutions to ensure the synchronization performance of the device in sleep mode.

[0113] The technical solutions of the embodiments of this application can be applied to various communication systems, such as wireless fidelity (WiFi) systems, vehicle-to-everything (V2X) communication systems, device-to-device (D2D) communication systems, vehicle-to-everything (V2X) communication systems, 4th generation (4G) mobile communication systems, such as long term evolution (LTE) systems, 5th generation (5G) mobile communication systems, such as new radio (NR) systems, and future communication systems, such as 6th generation (6G). Of course, future communication systems may also have other naming methods, which are still covered within the scope of this application, and this application does not impose any limitations on them.

[0114] This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches are also possible.

[0115] Furthermore, in the embodiments of this application, the words "exemplary," "for example," etc., are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0116] In the embodiments of this application, the terms "information," "signal," "message," "channel," and "singaling" may sometimes be used interchangeably. It should be noted that when their distinctions are not emphasized, their intended meanings are consistent. Similarly, "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that when their distinctions are not emphasized, their intended meanings are consistent. Furthermore, the " / " mentioned in this application can be used to indicate an "or" relationship. In the embodiments of this application, "same" does not necessarily mean that two things are completely identical; a certain degree of difference between two things can also be considered "same." That is, "same" can be understood as "similar" or "roughly the same."

[0117] To facilitate understanding of the embodiments of this application, let's first take... Figure 8The communication system illustrated herein is used as an example to illustrate a communication system applicable to embodiments of this application. For example, Figure 8 This is a schematic diagram of the architecture of a communication system to which the communication method provided in the embodiments of this application is applicable.

[0118] like Figure 8 As shown, the communication system includes: terminals and network equipment.

[0119] The aforementioned terminal is a terminal that accesses a network and has wireless transceiver capabilities, or may be located in a chip or chip system within the terminal. This terminal may also be referred to as user equipment (UE), access terminal, subscriber unit, user station, mobile station (MS), mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user equipment. The terminals in the embodiments of this application may be mobile phones, cellular phones, smartphones, tablets, wireless data cards, personal digital assistants (PDAs), wireless modems, handsets, laptop computers, machine-type communication (MTC) terminals, computers with wireless transceiver capabilities, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, vehicle-mounted terminals, roadside units (RSUs) with terminal functions, etc. The terminal of this application may also be an on-board module, on-board unit, on-board component, on-board chip or on-board unit that is built into a vehicle as one or more components or units.

[0120] The aforementioned network equipment, such as access network equipment, is a device located on the network side of the aforementioned communication system and having wireless transceiver capabilities, or a chip or chip system that can be installed in the device. This network equipment may include: access network equipment for next-generation mobile communication systems, such as 6G, such as a 6G base station, or a 6G core network element. Alternatively, in next-generation mobile communication systems, the network equipment may have other naming conventions, all of which are covered within the protection scope of the embodiments of this application, and this application does not impose any limitations on them. Furthermore, the network equipment may also include 5G, such as a gNB in ​​an NR system, or one or a group (including multiple antenna panels) of an antenna panel in a 5G base station. Alternatively, it may be a network node constituting a gNB, a transmission and reception point (TRP) or transmission point (TP), or a transmission measurement function (TMF), such as a building baseband unit (BBU), or a centralized unit (CU) or distributed unit (DU), an RSU with base station functionality, or a wired access gateway, or a 5G core network element. In addition, network devices can also include access points (APs) in wireless fidelity (WiFi) systems, wireless relay nodes, wireless backhaul nodes, various forms of macro base stations, micro base stations (also known as small stations), relay stations, access points, wearable devices, vehicle-mounted devices, and so on.

[0121] The above describes the communication system to which the communication method provided in the embodiments of this application is applicable. The following will be combined with... Figures 9-18 The communication method provided in the embodiments of this application will be described in detail.

[0122] For example, the communication method provided in this application embodiment can be applied to communication between a first device and a second device, wherein the first device and the second device can be... Figure 8The communication system shown includes terminals or network devices. For example, the first device is a terminal and the second device is a network device. Alternatively, both the first and second devices may be network devices. Another example is that both the first and second devices are terminals. Yet another example is that the first device is a network device and the second device is a terminal. In the communication method provided in this application embodiment, the first device can send a signal containing a synchronization signal and a reference frequency signal. Upon receiving this signal, the second device can eliminate the frequency offset generated by the synchronization signal during demodulation based on the frequency offset generated by the reference frequency signal during demodulation, thereby accurately determining the time-domain position of the correlation peak, completing device synchronization, and ensuring the synchronization performance of the device in sleep mode. The communication method provided in this application embodiment is described below with reference to specific steps.

[0123] Please see Figure 9 , Figure 9 The flowchart of the communication method provided in the embodiment of this application is shown. The communication method includes: S901, S902 and S903.

[0124] S901, the first device determines the first signal.

[0125] The first signal includes a first synchronization signal and N reference frequency signals, where N is a positive integer.

[0126] The aforementioned first synchronization signal is used for device synchronization, for example, for a second device to synchronize with the first device based on the first synchronization signal. The first synchronization signal can be represented as s. sync (t), 0 <t≤T sym T sym The duration of the first synchronization signal.

[0127] The aforementioned N reference frequency signals are used to eliminate the frequency offset generated by the first synchronization signal during demodulation, thereby achieving more accurate device synchronization. Each of the N reference frequency signals can be a single-frequency signal. For example, the i-th reference frequency signal among the N reference frequency signals can be represented as... Where i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym The duration of the i-th reference frequency signal is the same as, or similar to, the duration of the first synchronization signal. It's important to understand that the same duration for the first synchronization signal and the i-th reference frequency signal is merely an example and not a limitation. For instance, the durations of the first synchronization signal and the i-th reference frequency signal can also be different. For N reference frequency signals, their frequency domain positions or time domain positions can be the same or different, as will be discussed in detail below.

[0128] Of the N reference frequency signals, at least two reference frequency signals are located at different frequency domain positions, such as continuous or discontinuous frequency domain positions, or their frequencies can be considered to be different. Typically, the frequency response of a wireless channel is not always flat and fluctuates with environmental changes. If a frequency experiences fading, such as deep fading, it is difficult to eliminate the frequency offset of the first synchronization signal based on the reference frequency signal at that deeply faded frequency, making it difficult to determine the time domain position of the correlation peak and thus failing to guarantee the synchronization performance of the device in sleep mode. However, if the at least two reference frequency signals are located at different frequencies, the probability that all of these frequencies have experienced deep fading is relatively low. As long as one frequency has not experienced deep fading, the frequency offset of the first synchronization signal can be eliminated based on the frequency offset of the reference frequency signal at the non-deeply faded frequency, completing device synchronization and further ensuring the synchronization performance of the device in sleep mode. This is the so-called frequency diversity gain. It should be noted that the specific implementation principle of eliminating the frequency offset of the first synchronization signal based on the frequency offset of the reference frequency signal can be found in the relevant introduction in "S903" below, and will not be repeated here. Taking two reference frequency signals as an example, reference frequency signal 1 is located at frequency 1, and reference frequency signal 2 is located at frequency 2. If deep fading occurs at frequency 1, reference frequency signal 2 at frequency 2 can be used to eliminate the frequency offset of the first synchronization signal, thus completing device synchronization. Similarly, if deep fading occurs at channel 2, reference frequency signal 1 at frequency 1 can be used to eliminate the frequency offset of the first synchronization signal, thus completing device synchronization.

[0129] Specifically, in one possible implementation, at least two of the N reference frequency signals are located at the same time domain position. This saves time domain resources and improves resource utilization and communication efficiency. These at least two reference frequency signals can generate a frequency offset closer to the first synchronization signal during demodulation, thereby minimizing the frequency offset of the first synchronization signal and further ensuring the synchronization performance of the device in sleep mode. Taking two reference frequency signals as an example, with reference frequency signal 1 located at frequency 1 and reference frequency signal 2 located at frequency 2, reference frequency signal 1 and reference frequency signal 2 are located in time unit 1. The time unit can be a symbol, slot, mini-slot, subframe, radio frame, etc., and this application does not specifically limit it.

[0130] Alternatively, in another possible implementation, at least two of the N reference frequency signals are located at different time-domain positions. Taking two reference frequency signals as an example, with reference frequency signal 1 located at frequency 1 and reference frequency signal 2 located at frequency 2, reference frequency signal 1 is located in time unit 1, and reference frequency signal 2 is located in time unit 2. Thus, during demodulation, the device (e.g., a second device) can receive each reference frequency signal individually, avoiding interference from other reference frequency signals, thereby minimizing the frequency offset of the first synchronization signal and further ensuring the synchronization performance of the device in sleep mode. Furthermore, at least two of the N reference frequency signals are located at consecutive time-domain positions. For example, some of the N reference frequency signals are located at consecutive time-domain positions, while others are located at discontinuous time-domain positions, meaning there are time-domain intervals between the other part of the reference frequency signals. Another example is that the N reference frequency signals are located at consecutive time-domain positions, meaning that the time-domain positions of two adjacent reference frequency signals are consecutive. Thus, transmitting at consecutive time delay positions can ensure that the at least two reference frequency signals generate more similar frequency offsets during demodulation, thereby minimizing the frequency offset of the first synchronization signal and ensuring the synchronization performance of the device in sleep mode. Taking two reference frequency signals as an example, with reference frequency signal 1 located at frequency 1 and reference frequency signal 2 located at frequency 2, reference frequency signal 1 located at time unit 1 and reference frequency signal 2 located at time unit 2.

[0131] For the first synchronization signal and the N reference frequency signals as a whole, the time domain positions of the first synchronization signal and the N reference frequency signals are different. In other words, the time domain positions of the first synchronization signal and any one of the N reference frequency signals do not overlap.

[0132] In one possible approach, the first synchronization signal and N reference frequency signals are located at consecutive time-domain positions. For example... Figure 10 As shown in (a), taking two reference frequency signals as an example, the first synchronization signal is located in time unit 1, reference frequency signal 1 is located in time unit 2, and reference frequency signal 2 is located in time unit 3.

[0133] In another possible approach, the first synchronization signal and the N reference frequency signals are located in discontinuous time domain positions. For example... Figure 10 As shown in (b), the first synchronization signal is located in time unit 1, the reference frequency signal 1 is located in time unit 3, and the reference frequency signal 2 is located in time unit 4.

[0134] In another possible approach, the time-domain positions of the N reference frequency signals can be located before the time-domain position of the first synchronization signal. For example... Figure 11 As shown in (a) above, taking two reference frequency signals as an example, reference frequency signal 1 and reference frequency signal 2 are located in time unit 1, and the first synchronization signal is located in time unit 2. For example... Figure 11 As shown in (b), taking two reference frequency signals as an example, reference frequency signal 1 is located in time unit 1, reference frequency signal 2 is located in time unit 2, and the first synchronization signal is located in time unit 3.

[0135] In another possible approach, the time-domain positions of the N reference frequency signals can be located after the time-domain position of the first synchronization signal. For example... Figure 11 As shown in (c), taking two reference frequency signals as an example, the first synchronization signal is located in time unit 1, and reference frequency signal 1 and reference frequency signal 2 are located in time unit 2. For example... Figure 11 As shown in (d) above, taking two reference frequency signals as an example, the first synchronization signal is located in time unit 1, reference frequency signal 1 is located in time unit 2, and reference frequency signal 2 is located in time unit 3. Alternatively, the time domain position of some of the N reference frequency signals can be located before the time domain position of the first synchronization signal, and the time domain position of another part of the N reference frequency signals can be located after the time domain position of the first synchronization signal. For example... Figure 11 As shown in (e), taking two reference frequency signals as an example, reference frequency signal 1 is located in time unit 1, the first synchronization signal is located in time unit 2, and reference frequency signal 2 is located in time unit 3.

[0136] The first device determining the first signal may refer to: the first device modulating the first sequence, for example, based on OFDM modulation of the first sequence, to obtain the first signal.

[0137] The first sequence may include a first synchronization sequence and N reference frequency sequences. The first synchronization sequence can be selected from sequences with good autocorrelation characteristics. For example, these sequences with good autocorrelation characteristics could be Zadoff-Chu sequences or Gold sequences. The first synchronization sequence can be pre-configured locally on the first device, or the first device can obtain it from other devices beforehand. The first synchronization sequence is used to modulate a first synchronization signal, which can be represented as s. sync (n), 0 <n≤N sym N sym This refers to the number of sampling points of the digital-to-analog converter in the first device. In other words, the first device modulates the discrete synchronization sequence into a continuous signal by performing OFDM modulation and digital-to-analog conversion on the first synchronization sequence, thus obtaining the first synchronization signal.

[0138] Among them, N reference frequency sequences are used to modulate and obtain N reference frequency signals, and the i-th reference frequency sequence in the N reference frequency sequences can be represented as: f s Let N be the sampling frequency of the digital-to-analog converter in the first device. That is, the first device modulates the i-th reference frequency sequence using OFDM to convert N... sym A discrete reference frequency sequence is modulated into a continuous signal and mapped onto a carrier frequency f. i This yields the i-th reference frequency signal. Optionally, the carrier frequency f i The frequency can be any frequency within the bandwidth occupied by the WUR, and this application embodiment does not impose specific limitations. It should be noted that the specific implementation process of OFDM modulation described in this application embodiment can be referred to the relevant description in "1. OFDM" above, and will not be repeated here. The use of OFDM modulation in this application embodiment is merely an example; this application embodiment can also use any other possible modulation method, and is not specifically limited thereto.

[0139] S902, the first device sends a first signal. Correspondingly, the second device receives the first signal.

[0140] The synchronization signal can be carried on the first time-frequency resource. The first time-frequency resource is the time-frequency resource corresponding to the wake-up link. Here, "first time-frequency resource" is merely an exemplary naming method; it can also be replaced by "first frequency," "first resource," "first resource set," or "first time-frequency resource set," etc., and this application does not specifically limit it in this regard. Correspondingly, the time-frequency resource corresponding to the main link can be referred to as the second time-frequency resource. Of course, "second time-frequency resource" is also merely an exemplary naming method; it can also be replaced by "second frequency," "second resource," "second resource set," or "second time-frequency resource set," etc., and this application does not specifically limit it in this regard.

[0141] S903, the second device analyzes the first signal.

[0142] The process of the second device parsing the first signal can be considered as the second device analyzing and processing the first signal. Alternatively, it can be understood as the second device demodulating the first signal to determine the time-domain location of the relevant peaks. The demodulation process is described in detail below.

[0143] The second device demodulates the first signal to obtain a synchronization sequence with frequency offset and N reference frequency sequences with frequency offset. The synchronization sequence with frequency offset is the sequence obtained by demodulating the first synchronization signal. For example, the first synchronization signal is represented as s. sync (t), 0 <t≤T sym T symThe duration of the first synchronization signal is given. Based on this, the second device can down-convert the first synchronization signal using a low-power local crystal oscillator and a mixer to obtain a frequency-offset synchronization signal. This frequency-offset synchronization signal can be expressed as... f offset The frequency offset is due to the local crystal oscillator's frequency deviation. A second device can sample the frequency offset synchronization signal using an analog-to-digital converter to obtain a synchronization sequence with frequency deviation. This synchronization sequence with frequency deviation can be represented as... f s The sampling frequency of the analog-to-digital converter, 0 <n≤N sym N sym Let be the number of sampling points of the analog-to-digital converter in the second device. Similarly, the i-th reference frequency signal is represented as... f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let be the duration of the i-th reference frequency signal. Based on this, the second device can down-convert the i-th reference frequency signal using a low-power local crystal oscillator and a mixer to obtain the i-th frequency offset reference frequency signal. This i-th frequency offset reference frequency signal can be expressed as: f offset The frequency offset is due to the local crystal oscillator's frequency deviation. A second device can sample the frequency offset synchronization signal using an analog-to-digital converter to obtain a synchronization sequence with frequency deviation. This synchronization sequence with frequency deviation can be represented as... f s The sampling frequency of the analog-to-digital converter, 0 <n≤N sym N sym This refers to the number of sampling points of the analog-to-digital converter in the second device. It is understood that the specific demodulation process described in the embodiments of this application can also be found in the relevant descriptions in "1. OFDM" and "3. Main Link and Wake-up Link" above, and will not be repeated here.

[0144] Subsequently, the second device can determine the time-domain location of the correlation peak based on the frequency-biased synchronization sequence, N frequency-biased reference frequency sequences, the first synchronization sequence, and the N reference frequency sequences. Specifically, the second device can first eliminate the frequency bias using the frequency-biased synchronization sequence and the N frequency-biased reference frequency sequences. For example, the second device multiplies the frequency-biased synchronization sequence with the conjugate transpose of the i-th frequency-biased reference frequency sequence to obtain the i-th conjugate transpose sequence, which is the sequence with the frequency bias eliminated. Then, the second device accurately determines the time-domain location of the correlation peak based on the first synchronization sequence and the N reference frequency sequences. For example, the second device performs correlation operations on the i-th conjugate transpose sequence, the first synchronization sequence, and the i-th reference frequency sequence to obtain the exact time-domain location of the correlation peak.

[0145] It should be noted that conjugate transpose multiplication can be: the sequence obtained by multiplying the frequency-biased synchronization sequence by the conjugate of the i-th frequency-biased reference frequency sequence, or the sequence obtained by multiplying the frequency-biased reference frequency sequence by the conjugate of the frequency-biased synchronization sequence. For example, the frequency-biased synchronization sequence is represented as follows: The conjugate sequence of the i-th reference frequency sequence with frequency offset is represented as follows: Conjugate transpose multiplication is represented as This eliminates the influence of frequency offset, ensuring that the time-domain location of the relevant peak can be accurately determined subsequently. Furthermore, since the conjugate transpose multiplication has no limitation on the magnitude of the frequency offset, even large frequency offsets can be eliminated.

[0146] For ease of understanding, the following examples illustrate the above analysis process using one reference frequency signal, two reference frequency signals located at different time domain positions, and two reference frequency signals located at the same time domain position.

[0147] Case 1: One reference frequency signal (denoted as reference frequency signal 1).

[0148] in, Figure 12 The time-frequency positional relationship between reference frequency signal 1 and the first synchronization signal is shown. Figure 13 The temporal positional relationship between reference frequency signal 1 and the first synchronization signal is shown. For example... Figure 12 and Figure 13 As shown, in the signal received by the second device, the reference frequency signal 1 and the first synchronization signal are located in consecutive time domain positions. After down-converting the received signal, the second device can perform sliding sampling on the down-converted signal based on a digital-to-analog converter. Since the reference frequency signal and the first synchronization signal occupy two time domain positions, the second device can use two sliding windows (denoted as the first sliding window and the second sliding window) to perform sliding sampling on the down-converted signal. The length of the first sliding window matches the duration of the first synchronization signal, and the length of the second sliding window matches the duration of the reference frequency signal 1. The time domain positional relationship between the first and second sliding windows matches the time domain positional relationship between the reference frequency signal 1 and the first synchronization signal. For example, the spacing between the first and second sliding windows is the same as the spacing between the first synchronization signal and the reference frequency signal 1. The first and second sliding windows are located in consecutive time domain positions.

[0149] After the second device performs a sampling based on the first and second sliding windows, it can move the first and second sliding windows along the path shown in the image. Figure 13The sampling point is moved in the direction of the middle arrow, and then the next sampling is performed. Each sliding sample of the first and second sliding windows refers to extracting N samples from the corresponding positions in the signal. sym Each sampling point yields its own sampling sequence. Taking the l-th sliding window as an example, the sequence obtained from the first sliding window sampling is denoted as sequence 1, and can be represented as r l,1 (n) = r(l+n). The sequence obtained by the second sliding window sampling is denoted as sequence 2, and can be represented as r l,2 (n) = r(l + D + n), where D is the distance between the first and second sliding windows, for example, D = N. sym Then, the second device can multiply sequence 1 by the conjugate transpose of sequence 2 to obtain the conjugate transpose sequence, which can be represented as... Finally, the second device performs a correlation operation on the conjugate transpose sequence, as well as the first synchronization sequence and reference frequency sequence 1 pre-saved by the second device, to obtain a correlation value. This correlation value can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device uses a pre-saved reference frequency sequence 1. That is, each time a sampling point is slid, a correlation value is obtained, which is used to detect the correlation peak.

[0150] If the first sliding window slides to coincide with the first synchronization signal of the down-conversion, then the second sliding window also slides to coincide with the reference frequency signal 1 of the down-conversion. At this time, sequence 1 sampled by the first sliding window is the first synchronization sequence of the down-conversion, that is, the synchronization sequence with frequency offset, which can be represented as... s sync (n) is the first synchronization sequence, f s f is the sampling frequency of the analog-to-digital converter in the second device. offset This represents the frequency offset generated by the first synchronization signal during the down-conversion process. Sequence 2, sampled by the second sliding window, is the reference frequency sequence 1 for the down-conversion, i.e., the reference frequency sequence 1 with a frequency offset, which can be expressed as... f1 is the frequency of reference frequency sequence 1, f offset The frequency offset is generated by the reference frequency signal 1 during the down-conversion process. The second device can multiply the synchronization sequence with the frequency offset by the conjugate transpose of the reference frequency sequence 1 to obtain the conjugate transpose sequence. This conjugate transpose sequence can be represented as... This eliminates the effect of frequency offset. Thus, the second device performs a correlation operation on this conjugate transpose sequence, along with the first synchronization sequence and reference frequency sequence 1 pre-stored by the second device, obtaining the maximum correlation value. This correlation value can be expressed as... s sync(n) represents the first synchronization sequence pre-saved by the second device. A reference frequency sequence 1 is pre-saved for the second device. Thus, the second device can determine the time-domain position of the correlation peak, i.e., the alignment position, based on this correlation value, thereby achieving synchronization.

[0151] Case 2: Two reference frequency signals (denoted as reference frequency signal 1 and reference frequency signal 2), which are located at different time domain positions.

[0152] in, Figure 14 The time-frequency positional relationship of reference frequency signal 1, reference frequency signal 2, and the first synchronization signal is shown. Figure 15 The temporal positional relationship of reference frequency signal 1, reference frequency signal 2, and the first synchronization signal is shown. For example... Figure 14 and Figure 15 As shown, in the signal received by the second device, reference frequency signal 1, reference frequency signal 2, and the first synchronization signal are located at consecutive time domain positions. After down-converting the received signal, the second device can perform sliding sampling on the down-converted signal based on a digital-to-analog converter. Since reference frequency signal 1, reference frequency signal 2, and the first synchronization signal occupy three time domain positions, the second device can use three sliding windows (denoted as the first sliding window, the second sliding window, and the third sliding window) to perform sliding sampling on the down-converted signal. The length of the first sliding window matches the duration of the first synchronization signal, the length of the second sliding window matches the duration of reference frequency signal 1, and the length of the third sliding window matches the duration of reference frequency signal 3. The time domain positional relationship between the first, second, and third sliding windows matches the time domain positional relationship between reference frequency signal 1, reference frequency signal 2, and the first synchronization signal. For example, the spacing between the first and second sliding windows is the same as the spacing between the first synchronization signal and reference frequency signal 1. The spacing between the first and third sliding windows is the same as the spacing between the first synchronization signal and the reference frequency signal 2. The first, second, and third sliding windows are located sequentially in consecutive time-domain positions.

[0153] After the second device performs a sampling based on the first, second, and third sliding windows, it can then move the first, second, and third sliding windows along... Figure 15 The sampling point is moved in the direction of the middle arrow, and then the next sampling is performed. Each sliding sample of the first, second, and third sliding windows refers to extracting N samples from the corresponding position in the signal. sym Each sampling point yields its own sampling sequence. Taking the l-th sliding window as an example, the sequence obtained from the first sliding window sampling is sequence 1, which can be represented as r l,1(n) = r(l+n). The sequence obtained by the second sliding window sampling is denoted as sequence 2, and can be represented as r l,2 (n) = r(l + D1 + n), where D1 is the distance between the first and second sliding windows, for example, D1 = N sym The sequence obtained by the third sliding window sampling is denoted as sequence 3, and can be represented as r. l,3 (n) = r(l + D2 + n), where D2 is the distance between the first and third sliding windows, for example, D2 = 2N. sym Then, the second device multiplies sequence 1 by the conjugate transpose of sequence 2 to obtain the conjugate transpose sequence 1, which can be represented as... The second device multiplies sequence 1 by the conjugate transpose of sequence 3 to obtain the conjugate transpose sequence 2, which can be represented as: Finally, the second device performs a correlation operation on the conjugate transpose sequence 1, as well as the first synchronization sequence and reference frequency sequence pre-saved by the second device, to obtain a correlation value of 1. This correlation value 1 can be represented as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device pre-stores a reference frequency sequence 1. The second device performs a correlation operation on this conjugate transpose sequence 2, along with the pre-stored first synchronization sequence and reference frequency sequence, to obtain a correlation value 2. This correlation value 2 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device has a pre-saved reference frequency sequence 2. That is, for each sliding sampling point, two correlation values ​​can be obtained, which can be used to detect the correlation peak.

[0154] If the first sliding window slides to coincide with the first synchronization signal of the down-conversion, then the second sliding window slides to coincide with the reference frequency signal 1 of the down-conversion, and the third sliding window slides to coincide with the reference frequency signal 2 of the down-conversion. At this time, sequence 1 sampled by the first sliding window is the first synchronization sequence of the down-conversion, that is, the synchronization sequence with frequency offset, which can be represented as... s sync (n) is the first synchronization sequence, f s f is the sampling frequency of the analog-to-digital converter in the second device. offset This represents the frequency offset generated by the first synchronization signal during the down-conversion process. Sequence 2, sampled by the second sliding window, is the reference frequency sequence 1 for the down-conversion, i.e., the reference frequency sequence 1 with a frequency offset, which can be expressed as... f1 is the frequency of reference frequency sequence 1, f offsetThe frequency offset is generated by the reference frequency signal 1 during the down-conversion process. Sequence 3 sampled by the third sliding window is the reference frequency sequence 2 for down-conversion, i.e., the reference frequency sequence 2 with a frequency offset, which can be represented as... f2 is the frequency of reference frequency sequence 2, f offset The frequency offset is generated by the frequency offset reference frequency signal 2 during the down-conversion process.

[0155] The second device can multiply the frequency-offset synchronization sequence with the frequency-offset reference frequency sequence 1 as its conjugate transpose to obtain the conjugate transpose sequence 1. The conjugate transpose sequence 1 can be represented as... This eliminates the effect of frequency offset. The second device can multiply the frequency-offset synchronization sequence with the frequency-offset reference frequency sequence 2 by its conjugate transpose to obtain the conjugate transpose sequence 2. The conjugate transpose sequence 2 can be expressed as... This also eliminates the effect of frequency offset. Thus, the second device performs a correlation operation on the conjugate transpose sequence 1, as well as the first synchronization sequence and reference frequency sequence 1 pre-saved by the second device, to obtain a correlation value of 1. This correlation value 1 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device pre-stores a reference frequency sequence 1. Similarly, the second device can also perform correlation operations on the conjugate transpose sequence 2, as well as the first synchronization sequence and reference frequency sequence 2 pre-stored by the second device, to obtain a correlation value 2. This correlation value 2 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. Reference frequency sequence 2, pre-saved for the second device.

[0156] Thus, the second device can determine the temporal position of the correlation peak, i.e., the alignment position, based on correlation value 1 and correlation value 2, thereby achieving synchronization. For example, if correlation value 1 is greater than the threshold used for correlation peak detection and correlation value 2 is less than the threshold, the temporal position of the correlation peak is determined based on correlation value 1. Alternatively, if correlation value 2 is greater than the threshold and correlation value 1 is less than the threshold, the temporal position of the correlation peak is determined based on correlation value 2. Or, if both correlation value 1 and correlation value 2 are greater than the threshold, the temporal position of the correlation peak is determined based on the larger of correlation value 1 and correlation value 2. This application does not limit the case where correlation value 1 and correlation value 2 are equal to the threshold. For example, when correlation value 1 is greater than or equal to the threshold and correlation value 2 is less than the threshold, the temporal position of the correlation peak can be determined based on correlation value 1. Alternatively, when correlation value 1 is greater than the threshold and correlation value 2 is less than or equal to the threshold, the temporal position of the correlation peak can be determined based on correlation value 1. Case 3: Two reference frequency signals (denoted as reference frequency signal 1 and reference frequency signal 2), with reference frequency signal 1 and reference frequency signal 2 located at the same time domain position.

[0157] in, Figure 16 The time-frequency positional relationship of reference frequency signal 1, reference frequency signal 2, and the first synchronization signal is shown. Figure 17 The temporal positional relationship of reference frequency signal 1, reference frequency signal 2, and the first synchronization signal is shown. For example... Figure 16 and Figure 17 As shown, in the signals received by the second device, reference frequency signal 1 and reference frequency signal 2 are located at the same time domain position, which is continuous with the time domain position of the first synchronization signal. After down-converting the received signal, the second device can perform sliding sampling on the down-converted signal based on a digital-to-analog converter. Since reference frequency signal 1, reference frequency signal 2, and the first synchronization signal occupy two time domain positions, the second device can use two sliding windows (denoted as the first sliding window and the second sliding window) to perform sliding sampling on the down-converted signal. The length of the first sliding window matches the duration of the first synchronization signal, and the length of the second sliding window matches the duration of reference frequency signal 1 and reference frequency signal 2. The time domain positional relationship between the first and second sliding windows matches the time domain positional relationship between reference frequency signal 1, reference frequency signal 2, and the first synchronization signal. For example, the spacing between the first and second sliding windows is the same as the spacing between the first synchronization signal and reference frequency signal 1. Furthermore, the spacing between the first and second sliding windows is also the same as the spacing between the first synchronization signal and reference frequency signal 2. The first and second sliding windows are located at continuous time domain positions.

[0158] After the second device performs a sampling based on the first and second sliding windows, it can then move the first and second sliding windows along the edges as shown in the image. Figure 17The sampling point is moved in the direction of the middle arrow, and then the next sampling is performed. Each sliding sample of the first and second sliding windows refers to extracting N samples from the corresponding positions in the signal. sym Each sampling point yields its own sampling sequence. Taking the l-th sliding window as an example, the sequence obtained from the first sliding window sampling is sequence 1, which can be represented as r l,1 (n) = r(l+n). The sequence obtained by the second sliding window sampling is sequence 2, which can be represented as r l,2 (n) = r(l + D1 + n), where D1 is the distance between the first and second sliding windows, for example, D1 = N sym Then, the second device multiplies sequence 1 by the conjugate transpose of sequence 2 to obtain the conjugate transpose sequence, which can be represented as... Finally, the second device performs a correlation operation on the conjugate transpose sequence, as well as the first synchronization sequence and reference frequency sequence 1 pre-saved by the second device, to obtain a correlation value of 1. This correlation value 1 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device pre-stores a reference frequency sequence 1. The second device performs a correlation operation on this conjugate transpose sequence, along with the first synchronization sequence and reference frequency sequence 2 pre-stored by the second device, to obtain a correlation value 2. This correlation value 2 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device has a pre-saved reference frequency sequence 2. That is, for each sliding sampling point, two correlation values ​​can be obtained, which can be used to detect the correlation peak.

[0159] If the first sliding window slides to coincide with the first synchronization signal of the down-conversion, then the second sliding window slides to coincide with both the reference frequency signal 1 and the reference frequency signal 2 of the down-conversion. At this time, sequence 1 sampled by the first sliding window is the first synchronization sequence of the down-conversion, i.e., the synchronization sequence with frequency offset, which can be represented as... s sync (n) is the first synchronization sequence, f s f is the sampling frequency of the analog-to-digital converter in the second device. offset The frequency offset generated by the first synchronization signal during the down-conversion process. The second sequence sampled by the second sliding window is the sum of the down-conversion reference frequency sequence 1 and the down-conversion reference frequency sequence 2, that is, the reference frequency sequence 1 with frequency offset + the reference frequency sequence 2 with frequency offset (denoted as the superimposed sequence), which can be expressed as... f1 is the frequency of reference frequency sequence 1, f2 is the frequency of reference frequency sequence 2, f offset This refers to the frequency deviation generated during the down-conversion process of either reference frequency signal 1 or reference frequency signal 2.

[0160] Based on this, the second device can multiply the synchronization sequence with frequency offset by the conjugate transpose of the superimposed sequence to obtain the conjugate transpose sequence. The conjugate transpose sequence can be represented as... That is, the conjugate transpose sequence eliminates the influence of frequency offset. Thus, the second device can perform correlation operations on the conjugate transpose sequence, as well as the first synchronization sequence and reference frequency sequence 1 pre-stored by the second device, to obtain a correlation value of 1. The correlation value 1 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device pre-stores a reference frequency sequence 1. Similarly, the second device can also perform correlation operations on the conjugate transpose sequence, as well as the first synchronization sequence and reference frequency sequence 2 pre-stored by the second device, to obtain a correlation value 2. This correlation value 2 can be expressed as... s sync (n) represents the first synchronization sequence pre-saved by the second device. The second device has a pre-saved reference frequency sequence 2. Thus, the second device can also determine the time-domain location of the correlation peak based on correlation value 1 and correlation value 2. For specific implementation details, please refer to the relevant description in "Case 2" above; further details will not be repeated here.

[0161] In summary, based on Figure 9 As shown in the method, the first signal includes a first synchronization signal and N reference frequency signals, each of which is a single-frequency signal. In this case, if demodulation is performed based on a local crystal oscillator, each reference frequency signal can generate a frequency offset similar to that of the first synchronization signal, thereby eliminating the frequency offset of the first synchronization signal. Thus, the device can perform correlation calculations using the frequency-offset-free synchronization signal, accurately determine the time-domain position of the correlation peak, complete device synchronization, and ensure the synchronization performance of the device in sleep mode.

[0162] Optionally, in one possible design, after S902, the communication method provided in this application embodiment may further include: a first device sending a wake-up signal. Correspondingly, a second device receiving the wake-up signal.

[0163] The wake-up signal can be carried on the wake-up link. The data in the wake-up signal is used to wake up the second device, triggering the second device to start the main link and enter the connected state.

[0164] The data in the wake-up signal can be carried based on a combination of the on or off states of resource units in a resource unit set, where the resource unit set belongs to the first time-frequency resource. It can be understood that carrying data based on combinations of the on or off states of resource units enables resource reuse, thereby improving communication efficiency and spectral efficiency. Optionally, a resource unit can occupy at least one OFDM symbol in time and at least one OFDM subcarrier in frequency. That is, the granularity of the resource unit can be selectively chosen according to the actual scenario, for example, it can be a RE or a resource block (RB) to ensure its applicability to the specific scenario.

[0165] Specifically, in one possible approach, the data in the wake-up signal includes at least one bit, and a combination of the on or off states of every two resource units in the resource unit set, used to transmit one bit corresponding to that at least one bit. For example, there are two combinations of the on or off states of every two resource units. The first combination is: the first resource unit is in the on state and the second resource unit is in the off state, used to transmit bit "1". The second combination is: the first resource unit is in the off state and the second resource unit is in the on state, used to transmit bit "0", which is binary on-off keying (OOK) modulation. For ease of understanding, an example is given below. Figure 18 The time-frequency domain distribution of the resource unit set is shown, such as... Figure 18 As shown, the resource element set comprises 80 REs, each consisting of 10 symbols and 8 subcarriers, with each RE being a resource element. (The text then repeats the description of REs.) 0,0 (This represents a RE consisting of subcarrier 0 and symbol 0, and the same applies below) and RE 0,1 For example, the first combination is: RE 0,0 RE is in the enabled state. 0,1 In the off state, the transmitted bit is 1. The second combination is: RE 0,0 RE is in the off state. 0,1 When in the enabled state, the transmitted bits are 0. In this case, the second device can determine the corresponding bit value by comparing the energy of resource units, without needing to determine the capacity threshold of individual resource units. This reduces the complexity of demodulation, thereby improving the operating efficiency of the second device and making better use of energy.

[0166] Alternatively, in another possible approach, the wake-up signal data includes at least one bit, a combination of the on or off states of every two resource unit groups (a resource unit group includes multiple resource units) in the resource unit set, used to transmit one bit corresponding to that at least one bit. For example, there are two combinations of the on or off states of every two resource unit groups. The first combination is: all resource units in the first resource unit group are on, and all resource units in the second resource unit group are off, used to transmit bit "1". The second combination is: all resource units in the first resource unit group are off, and all resource units in the second resource unit group are on, used to transmit bit "0". For ease of understanding, an example is provided below. Figure 18 As shown, RE 4,2 and RE 5,3 As a resource unit group, RE 4,3 and RE 5,2 This is another resource unit group. The first combination is: RE 4,2 and RE 5,3 All are in the ON state, RE 4,3 and RE 5,2 Both are in the off state and are used to transmit bit "1". The second combination is: RE 4,2 and RE 5,3 All are in the off state, RE 4,3 and RE 5,2 Both are in the ON state and are used to transmit bit "0". In this case, the second device can determine the corresponding bit value by comparing the energy of the resource unit groups, without having to determine the capacity threshold of individual resource units. This reduces the complexity of demodulation, thereby improving the operating efficiency of the second device and making better use of energy.

[0167] The above combination Figures 9-18 The communication method provided in the embodiments of this application is described in detail below. Figures 19-21 This document describes in detail the communication apparatus used to perform the communication method provided in the embodiments of this application.

[0168] For example, Figure 19 This is a schematic diagram of the structure of the communication device provided in the embodiments of this application. Figure 1 .like Figure 19 As shown, the communication device 1900 can be applied to Figure 9 The first device shown includes components for performing the above. Figure 9 The method shown includes various modules for the function of the first device, such as transceiver module 1901 and processing module 1902.

[0169] The processing module 1902 is used to determine the first signal; the transceiver module 1901 is used to transmit the first signal. The first signal is carried on a first time-frequency resource and includes a first synchronization signal and N reference frequency signals, where N is a positive integer. The first synchronization signal and the N reference frequency signals have different time-domain positions, and each of the N reference frequency signals is a single-frequency signal.

[0170] In one possible design, at least two of the N reference frequency signals are located at different frequency domain positions.

[0171] Optionally, at least two of the N reference frequency signals are located at the same time domain position. Alternatively, at least two of the N reference frequency signals are located at different time domain positions.

[0172] Furthermore, at least two of the N reference frequency signals are located in consecutive time domain positions.

[0173] In one possible design scheme, the i-th reference frequency signal among the N reference frequency signals is: i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let be the duration of the i-th reference frequency signal.

[0174] In one possible design, the transceiver module 1901 is further configured to send a wake-up signal after sending the first signal. The data in the wake-up signal is carried based on a combination of the on or off states of resource units in a resource unit set, where the resource unit set belongs to the first time-frequency resource.

[0175] Optionally, the resource element occupies at least one orthogonal frequency division multiplexing (OFDM) symbol in time and at least one OFDM subcarrier in frequency.

[0176] Optionally, the transceiver module 1901 may also include a transmitting module and a receiving module. Figure 19 (Not shown in the diagram). The transmitting module is used to implement the transmitting function of the communication device 1900, and the receiving module is used to implement the receiving function of the communication device 1900.

[0177] Optionally, the communication device 1900 may also include a storage module. Figure 19 (Not shown in the image), this storage module stores programs or instructions. When the processing module executes the program or instructions, it enables the communication device 1900 to perform operations. Figure 9 The function of the first device in the method shown.

[0178] It should be understood that the processing module involved in the communication device 1900 can be implemented by a processor or processor-related circuit components, and can be a processor or processing unit; the transceiver module can be implemented by a transceiver or transceiver-related circuit components, and can be a transceiver or transceiver unit.

[0179] It should be noted that the communication device 1900 may be a terminal or network device, or a chip (system) or other component or assembly that can be set in the terminal or network device, or a device that includes the terminal or network device. This application does not limit it in this respect.

[0180] In addition, the technical effects of the communication device 1900 can be referenced. Figure 9 The technical effects of the methods shown will not be elaborated here.

[0181] Or, such as Figure 19 As shown, the communication device 1900 can be applied to Figure 9 The second device shown includes a means for performing the above. Figure 9 The method shown includes various modules for the function of the second device, such as transceiver module 1901 and processing module 1902.

[0182] The transceiver module 1901 is used to receive the first signal; the processing module 1902 is used to parse the first signal. The first signal is carried on a first time-frequency resource and includes: a first synchronization signal and N reference frequency signals, where N is an integer. The first synchronization signal and the N reference frequency signals have different time-domain positions, and each of the N reference frequency signals is a single-frequency signal.

[0183] In one possible design, at least two of the N reference frequency signals are located at different frequency domain positions.

[0184] Optionally, at least two of the N reference frequency signals are located at the same time domain position. Alternatively, at least two of the N reference frequency signals are located at different time domain positions.

[0185] Furthermore, at least two of the N reference frequency signals are located in consecutive time domain positions.

[0186] In one possible design scheme, the i-th reference frequency signal among the N reference frequency signals is: i is any integer from 1 to N, f i Let be the frequency of the i-th reference frequency signal, 0 <t≤T sym T sym Let be the duration of the i-th reference frequency signal.

[0187] In one possible design, the processing module 1902 is further configured to demodulate the first signal to obtain a synchronization sequence with frequency offset and N reference frequency sequences with frequency offset, and to determine the time-domain position of the correlation peak based on the synchronization sequence with frequency offset, the N reference frequency sequences with frequency offset, the first synchronization sequence, and the N reference frequency sequences. Here, the synchronization sequence with frequency offset is the sequence obtained by demodulating the first synchronization signal, and the i-th reference frequency sequence with frequency offset among the N reference frequency sequences is the sequence obtained by demodulating the i-th reference frequency signal among the N reference frequency signals, where i is any integer from 1 to N. The first synchronization sequence is used to modulate the first synchronization signal, and the N reference frequency sequences are used to modulate the N reference frequency signals.

[0188] Optionally, the processing module 1902 is further configured to multiply the synchronization sequence with frequency offset by the conjugate transpose of the i-th reference frequency sequence with frequency offset to obtain the i-th conjugate transpose sequence, and perform correlation operations on the i-th conjugate transpose sequence, the first synchronization sequence and the i-th reference frequency sequence to determine the time domain position of the correlation peak.

[0189] In one possible design, the transceiver module 1901 is further configured to receive a wake-up signal after receiving the first signal. The data in the wake-up signal is carried as a combination of the on or off states of resource units in a resource unit set, where the resource unit set belongs to the first time-frequency resource.

[0190] Optionally, a resource element occupies at least one OFDM symbol in time and at least one carrier in frequency.

[0191] Optionally, the transceiver module 1901 may also include a transmitting module and a receiving module. Figure 19 (Not shown in the diagram). The transmitting module is used to implement the transmitting function of the communication device 1900, and the receiving module is used to implement the receiving function of the communication device 1900.

[0192] Optionally, the communication device 1900 may also include a storage module. Figure 19 (Not shown in the image), this storage module stores programs or instructions. When the processing module executes the program or instructions, it enables the communication device 1900 to perform operations. Figure 9 The function of the second device in the method shown.

[0193] It should be understood that the processing module involved in the communication device 1900 can be implemented by a processor or processor-related circuit components, and can be a processor or processing unit; the transceiver module can be implemented by a transceiver or transceiver-related circuit components, and can be a transceiver or transceiver unit.

[0194] It should be noted that the communication device 1900 may be a terminal or network device, or a chip (system) or other component or assembly that can be set in the terminal or network device, or a device that includes the terminal or network device. This application does not limit it in this respect.

[0195] In addition, the technical effects of the communication device 1900 can be referenced. Figure 9 The technical effects of the methods shown will not be elaborated here.

[0196] For example, Figure 20 Schematic diagram of the communication device provided in the embodiments of this application Figure 2 The communication device can be a terminal device or a network device, or it can be a chip (system) or other component or assembly that can be installed in the terminal device or network device. For example... Figure 20 As shown, the communication device 2000 may include a processor 2001. Optionally, the communication device 2000 may also include a memory 2002 and / or a transceiver 2003. The processor 2001 is coupled to the memory 2002 and the transceiver 2003, for example, they may be connected via a communication bus.

[0197] The following is combined with Figure 20 A detailed description of each component of the communication device 2000 is provided below:

[0198] The processor 2001 is the control center of the communication device 2000. It can be a single processor, a collective term for multiple processing elements, or a logic circuit. For example, the processor 201 can be one or more central processing units (CPUs), application-specific integrated circuits (ASICs), or one or more integrated circuits configured to implement the embodiments of this application, such as one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs).

[0199] Optionally, the processor 201 can perform various functions of the communication device 2000 by running or executing software programs stored in the memory 202 and calling data stored in the memory 202.

[0200] In a specific implementation, as one example, the processor 2001 may include one or more CPUs, for example... Figure 20 CPU0 and CPU1 are shown in the diagram.

[0201] In a specific implementation, as one example, the communication device 2000 may also include multiple processors, for example... Figure 20 The processors 2001 and 2004 are shown. Each of these processors can be a single-core processor or a multi-core processor. Here, "processor" can refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0202] The memory 2002 is used to store the software program that executes the solution of this application, and is controlled by the processor 2001, so that the above... Figure 9 The method shown was executed.

[0203] Optionally, the memory 2002 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. The memory 2002 may be integrated with the processor 2001 or exist independently, and may be connected via the interface circuit of the communication device 2000, or input / output interface. Figure 20 (Not shown in the image) is coupled to the processor 2001, and this embodiment does not specifically limit this.

[0204] Transceiver 2003 is used for communication with other communication devices. For example, if communication device 2000 is a terminal, transceiver 2003 can be used to communicate with a network device or with another terminal device. As another example, if communication device 20600 is a network device, transceiver 2003 can be used to communicate with a terminal or with another network device.

[0205] Alternatively, transceiver 2003 may include a receiver and a transmitter. Figure 20 (Not shown separately). The receiver is used to implement the receiving function, and the transmitter is used to implement the sending function.

[0206] Optionally, the transceiver 2003 can be integrated with the processor 2001, or it can exist independently and be connected via the interface circuit of the communication device 2000. Figure 20 (Not shown in the image) is coupled to the processor 2001, and this embodiment does not specifically limit this.

[0207] It should be noted that, Figure 20 The structure of the communication device 2000 shown in the figure does not constitute a limitation on the communication device. Actual communication devices may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0208] Furthermore, the technical effects of the communication device 2000 can be referred to the technical effects of the communication method described in the above method embodiments, and will not be repeated here.

[0209] For example, Figure 21 Schematic diagram of the communication device provided in the embodiments of this application Figure 3 The communication device can be a terminal device or a network device, or it can be a chip (system) or other component or assembly that can be installed in the terminal device or network device. For example... Figure 21 As shown, the communication device 2100 may include a logic circuit 2101 and an input / output interface 2102. The input / output interface 2102 is used to receive code instructions and transmit them to the logic circuit 2101. The logic circuit 2101 is used to execute the code instructions to perform the actions described above. Figure 9 The method shown.

[0210] Furthermore, the technical effects of the communication device 2100 can be referred to the technical effects of the communication method described in the above method embodiments, and will not be repeated here.

[0211] This application provides a communication system. The communication system includes one or more terminals as described above, and one or more network devices.

[0212] It should be understood that the processor in the embodiments of this application can be a CPU, but it can also be other general-purpose processors, DSPs, ASICs, field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0213] It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), EEPROM, or flash memory. Volatile memory can be RAM, which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0214] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0215] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0216] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0217] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0218] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0219] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0220] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0221] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0222] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0223] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0224] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, The method includes: The first device determines a first signal, which includes: a first synchronization signal and N reference frequency signals, where N is a positive integer. The first synchronization signal and the N reference frequency signals are located in different time domains, and each of the N reference frequency signals is a single-frequency signal. The first device sends a first signal, which is carried on a first time-frequency resource; The temporal position of the correlation peak is obtained by the second device from the conjugate transpose of the synchronization sequence with frequency offset and the i-th reference frequency sequence with frequency offset, which is the i-th conjugate transpose obtained by the second device. The synchronization sequence with frequency offset is the sequence obtained by the second device demodulating the first synchronization signal. The i-th reference frequency sequence with frequency offset is the sequence obtained by the second device demodulating the i-th reference frequency signal among the N reference frequency signals, where i is any integer from 1 to N.

2. The method according to claim 1, characterized in that, The N reference frequency signals have at least two reference frequency signals located at different frequency domain positions.

3. The method according to claim 2, characterized in that, At least two of the N reference frequency signals are located at the same time domain position.

4. The method according to claim 2, characterized in that, The N reference frequency signals have at least two reference frequency signals located at different time domain positions.

5. The method according to claim 4, characterized in that, The N reference frequency signals have at least two reference frequency signals located in consecutive time domain positions.

6. The method according to claim 1, characterized in that, The i-th reference frequency signal among the N reference frequency signals is: where i is any integer from 1 to N. Let i be the frequency of the i-th reference frequency signal. , The duration of the i-th reference frequency signal.

7. The method according to any one of claims 1-6, characterized in that, After the first device sends the first signal, the method further includes: The first device sends a wake-up signal, and the data in the wake-up signal is carried based on the following: a combination of the open or closed states of resource units in the resource unit set, and the resource unit set belongs to the first time-frequency resource.

8. The method according to claim 7, characterized in that, The resource element occupies at least one orthogonal frequency division multiplexing (OFDM) symbol in time and at least one OFDM subcarrier in frequency.

9. A communication method, characterized in that, The method includes: The second device receives a first signal, which is carried on a first time-frequency resource. The first signal includes a first synchronization signal and N reference frequency signals, where N is an integer. The time domain positions of the first synchronization signal and the N reference frequency signals are different. Each of the N reference frequency signals is a single-frequency signal. The second device analyzes the first signal; The temporal position of the correlation peak is obtained by multiplying the frequency-biased synchronization sequence with the conjugate transpose of the i-th frequency-biased reference frequency sequence, which is the i-th conjugate transpose of the synchronization sequence with frequency bias. The frequency-biased synchronization sequence is the sequence obtained by demodulating the first synchronization signal, and the i-th frequency-biased reference frequency sequence is the sequence obtained by demodulating the i-th reference frequency signal among the N reference frequency signals, where i is any integer from 1 to N.

10. The method according to claim 9, characterized in that, The N reference frequency signals have at least two reference frequency signals located at different frequency domain positions.

11. The method according to claim 10, characterized in that, At least two of the N reference frequency signals are located at the same time domain position.

12. The method according to claim 10, characterized in that, The N reference frequency signals have at least two reference frequency signals located at different time domain positions.

13. The method according to claim 12, characterized in that, The N reference frequency signals have at least two reference frequency signals located in consecutive time domain positions.

14. The method according to claim 9, characterized in that, The i-th reference frequency signal among the N reference frequency signals is: where i is any integer from 1 to N. Let i be the frequency of the i-th reference frequency signal. , The duration of the i-th reference frequency signal.

15. The method according to claim 9, characterized in that, The second device parses the first signal, including: The second device demodulates the first signal to obtain a synchronization sequence with frequency offset and N reference frequency sequences with frequency offset. The N reference frequency sequences with frequency offset include the i-th reference frequency sequence with frequency offset. The second device determines the time-domain position of the correlation peak based on the synchronization sequence with frequency offset, the N reference frequency sequences with frequency offset, the first synchronization sequence, and the N reference frequency sequences. The first synchronization sequence is used to modulate the first synchronization signal, and the N reference frequency sequences are used to modulate the N reference frequency sequences.

16. The method according to claim 15, characterized in that, The second device determines the time-domain position of the correlation peak based on the frequency-off synchronization sequence, the N frequency-off reference frequency sequences, the first synchronization sequence, and the N reference frequency sequences, including: The second device multiplies the synchronization sequence with frequency offset by the conjugate transpose of the i-th reference frequency sequence with frequency offset to obtain the i-th conjugate transpose sequence; The second device performs correlation operations on the i-th conjugate transpose sequence, the first synchronization sequence, and the i-th reference frequency sequence to determine the time-domain position of the correlation peak.

17. The method according to any one of claims 9-16, characterized in that, After the second device receives the first signal, the method further includes: The second device receives a wake-up signal, the data in the wake-up signal being carried in the following manner: a combination of the on or off states of resource units in a resource unit set, the resource unit set belonging to the first time-frequency resource.

18. The method according to claim 17, characterized in that, The resource element occupies at least one OFDM symbol in time and at least one carrier in frequency.

19. A communication device, characterized in that, The apparatus includes a module for performing the method as described in any one of claims 1-8.

20. A communication device, characterized in that, The apparatus includes a module for performing the method as described in any one of claims 9-18.

21. A communication device, characterized in that, The device includes: a processor and a memory; wherein, The memory is used to store computer instructions, which, when executed by the processor, cause the communication device to perform the method as described in any one of claims 1-18.

22. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program or instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-18.

23. A computer program product, characterized in that, The computer program product includes: a computer program or instructions that, when run on a computer, cause the computer to perform the method as described in any one of claims 1-18.

24. A communication system, characterized in that, The communication system includes: a first device and a second device, wherein the first device is configured to perform the method as described in any one of claims 1-8, and the second device is configured to perform the method as described in any one of claims 9-18.

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