Communication method and related apparatus

Abstract

A communication method and a related apparatus. In the method, synchronization signals are determined, and the synchronization signals are sent to a tag over a first time domain resource and a first frequency domain resource. The first time domain resource comprises M orthogonal frequency-division multiplexing (OFDM) symbols, and the first frequency domain resource comprises N*12 subcarriers, wherein M and N are both positive integers. The modulation mode of the synchronization signals is on-off keying (OOK). The synchronization signals comprise a first signal and a second signal; the first signal indicates that the second signal follows the first signal and the second signal is adjacent to the first signal; the second signal is used for time calibration; a duration T1 of the first signal and a duration T2 of the second signal are both fixed values; and the sum of T1 and T2 is equal to a duration of the M OFDM symbols. The present application achieves the design of synchronization signals for tags (i.e., passive tags or semi-passive tags) under different downlink signal bandwidths, thereby facilitating improvement of communication performance.

Description

Communication method and related device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 16, 2023, with application number 202311540375.2 and application name “Communication Methods and Related Devices”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a communication method and related devices. Background Art

[0003] With the increasing adoption of fifth-generation (5G) mobile communication technology, new radio (NR) machine-type communication (mMTC), and Internet of Things (IoT) communications, the number of connected IoT devices is growing daily. To address the challenges of reducing the cost and power consumption of IoT devices, the 3rd Generation Partnership Project (3GPP) has proposed passive IoT communication technology within the 5G NR system to meet the cost and power requirements of IoT applications.

[0004] In a passive IoT system, a reader transmits a high-level waveform to a passive tag. The tag receives the energy and reflects the information back to the reader via a reverse link. Currently, readers primarily use pulse interval encoding (PIE) for synchronization signal transmission. This synchronization signal is designed only for a downlink signal bandwidth of 12 subcarriers and is therefore incompatible with wider downlink signal bandwidths.

[0005] Summary of the Invention

[0006] The present application provides a communication method and related devices, which are compatible with the design of synchronization signals for passive tags under different downlink signal bandwidths, and are conducive to improving communication performance.

[0007] In a first aspect, the present application provides a communication method. Optionally, the method may be performed by a network device, a component or device (such as a processor, chip, or chip system) applied to the network device, or a logic module or software that can implement all or part of the network device functions. The method includes:

[0008] Determine the synchronization signal;

[0009] Sending the synchronization signal on a first time domain resource and a first frequency domain resource, where the first time domain resource includes M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where both M and N are positive integers;

[0010] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, and the sum of T1 and T2 is equal to the duration of the M OFDM symbols.

[0011] In the present application, the synchronization signal is a signal sent by a network device to a passive tag or a semi-passive tag, wherein the synchronization signal can also be called a synchronization signal of a passive tag, or a leading signal, or a leading signal of a data signal, or a leading signal of a passive tag, or a leading signal of a passive tag data signal, etc. These names are just examples, and other names can also be used in specific implementations. This application does not make specific restrictions on this. It should be noted that this application is different from the current design of the synchronization signal, which only considers the design when the downlink signal bandwidth is 12 subcarriers. This application is compatible with the design of synchronization signals for passive tags under different downlink signal bandwidths, increases the flexibility of downlink transmission, and is conducive to improving communication performance. At the same time, under different bandwidths, the fixed duration T1 of the first signal is conducive to meeting the requirements of the duration of the passive tag delimiter, and the fixed duration T2 of the second signal is conducive to clock detection.

[0012] In one possible design, any level included in the first signal is a first level.

[0013] In this implementation, the first level can be understood as a low level or OOK symbol {0} or OOK chip {0}. The first signal is a fully low-level signal. This allows the receiving circuit sufficient buffer time before receiving the second signal and data signal, minimizing confusion between the first signal and subsequent second signal and data signal, thereby improving demodulation performance.

[0014] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0015] In this implementation, the second level can be understood as a high level, an OOK symbol {1}, or an OOK chip {1}. The number of first levels included in the second signal is equal to the number of second levels, and the duration of the second level is equal to the duration of the first level. This allows the design of the synchronization signal including the second signal to satisfy level time detection using Manchester coding for subsequent data, where Manchester coding is beneficial for improving communication performance of data transmission.

[0016] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0017] In this implementation, the second signal can specifically be a signal in which the {0} and {1} levels alternate, with the number of {0} and {1} being equal. For example, the second signal can be {010101}. Alternatively, the second signal can be a signal in which the {1} and {0} levels alternate, with the number of {0} and {1} being equal. For example, the second signal can be {101010}. This design of a signal sequence in which different levels alternate is relatively simple, and the rising and falling edges appear periodically, which helps reduce the detection complexity per unit level time while ensuring detection performance.

[0018] In one possible design, the duration of one OFDM symbol is T;

[0019] The duration T1 of the first signal satisfies: T1=M*T*X;

[0020] The duration T2 of the second signal satisfies: T2=M*T*(1-X);

[0021] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0022] In this implementation, the duration T1 of the first signal and the duration T2 of the second signal that satisfy the above formula can adapt to the adaptive design of the fixed time of the first signal and the fixed time of the second signal under different signal bandwidths. In addition, when M = 1, the value of X is associated with the subcarrier spacing, which can meet the requirements for the duration of the passive tag delimiter under different subcarrier spacings.

[0023] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N, and the number P2 of levels included in the second signal is proportional to the value of N.

[0024] In this implementation, the number P1 of levels included in the first signal and the number P2 of levels included in the second signal are proportional to the value of N, which can adapt to the design of the first signal under different signal bandwidths and improve the applicability of the solution.

[0025] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0026] The number P2 of levels included in the second signal satisfies: P2=M*K*N*(1-X);

[0027] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0028] In this implementation, the number of levels that satisfy the above formula can meet the requirements for the number of rising edges and falling edges of the time calibration level, thereby ensuring the performance of time detection.

[0029] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0030] In this implementation, the second signal contains ≥2 or 4 levels (preferred), which ensures the number of levels available for clock calibration of the tag and helps improve the accuracy of obtaining level boundaries (symbol boundaries) during detection.

[0031] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0032] In this implementation, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2, which can effectively ensure the buffer time for data reception when the tag is started (that is, when X is 1 / 3 or 1 / 2, under different bandwidths, the duration of the first signal is not shorter than the prescribed duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs)).

[0033] In a second aspect, the present application provides a communication method. Optionally, the execution subject of the method can be a network device, or a component or device applied to the network device (such as a processor, chip, or chip system, etc.), or a logic module or software that can implement all or part of the network device functions. The method includes:

[0034] Determine the synchronization signal;

[0035] Sending the synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, the first frequency domain resource includes N*12 subcarriers, and both M and N are positive integers;

[0036] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

[0037] In this application, the synchronization signal is a signal sent by a network device to a passive tag or semi-passive tag. Unlike the current design of the synchronization signal, which only considers the design when the downlink signal bandwidth is 12 subcarriers, this application is compatible with the design of synchronization signals for passive tags under different downlink signal bandwidths, which is conducive to improving communication performance. At the same time, under different bandwidths, keeping the duration T1 of the first signal fixed is conducive to meeting the requirements for the duration of the passive tag delimiter, and keeping the number of levels P2 included in the second signal unchanged can effectively ensure the number of levels that can be used when the tag performs clock calibration, and improve the peak rate of downlink transmission.

[0038] In one possible design, any level included in the first signal is a first level.

[0039] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0040] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0041] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0042] In this implementation, the duration T2 of the second signal is inversely proportional to the value of N, which is an adaptive design for the fixed time of the first signal and the fixed number of levels of the second signal. This is conducive to enhancing the flexibility of downlink transmission under different bandwidths and improving the transmission peak rate.

[0043] In one possible design, the duration of one OFDM symbol is T;

[0044] The duration T1 of the first signal satisfies: T1=M*T*X;

[0045] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0046] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0047] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N.

[0048] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0049] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0050] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0051] In this implementation, the second signal contains ≥2 or 4 levels (preferred), which ensures the number of levels available for clock calibration of the tag and helps improve the accuracy of obtaining level boundaries (symbol boundaries) during detection.

[0052] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0053] In this implementation, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2, which can effectively ensure the buffer time for data reception when the tag is started (that is, when X is 1 / 3 or 1 / 2, under different bandwidths, the duration of the first signal is not shorter than the prescribed duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs)).

[0054] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0055] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0056] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0057] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0058] In this implementation, the introduction of the third signal enables the tag to obtain more energy, which is conducive to maintaining normal communication.

[0059] In one possible design, P2 is equal to 4.

[0060] In this implementation, the number of levels included in the second signal is fixed to 4, which can ensure the number of levels that can be used when the tag performs clock calibration. In addition, it also maximizes the transmission peak rate of the tag.

[0061] In a third aspect, the present application provides a communication method. Optionally, the execution subject of the method can be a network device, or a component or device applied to the network device (such as a processor, chip, or chip system, etc.), or a logic module or software that can implement all or part of the network device functions. The method includes:

[0062] Determine the synchronization signal;

[0063] Sending the synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, the first frequency domain resource includes N×12 subcarriers, and both M and N are positive integers;

[0064] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, and the number P2 of levels included in the second signal is a fixed value.

[0065] In this application, the synchronization signal is a signal sent by a network device to a passive tag or semi-passive tag. Unlike the current synchronization signal design, which only considers the design when the downlink signal bandwidth is 12 subcarriers, this application is compatible with the design of synchronization signals for passive tags under different downlink signal bandwidths, which is beneficial to improving communication performance. At the same time, under different bandwidths, the sum of the duration T1 of the first signal and the duration of the first level in the second signal remains constant, which is beneficial to meeting the requirements for the duration of the passive tag delimiter, and the duration T2 of the second signal remains constant, which is beneficial to clock detection.

[0066] In one possible design, any level included in the first signal is a first level.

[0067] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0068] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0069] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0070] In this implementation, the duration T2 of the second signal is inversely proportional to the value of N, which is an adaptive design for keeping the time of the first level of the first signal + the second signal fixed and the number of fixed levels of the second signal. This is conducive to enhancing the flexibility of downlink transmission under different bandwidths and improving the transmission peak rate.

[0071] In one possible design, the duration of one OFDM symbol is T;

[0072] The duration T1 of the first signal satisfies: T1=M*T*X-M*T / K*N;

[0073] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0074] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0075] In one possible design, the sum of the number P1 of levels included in the first signal and 1 is proportional to the value of N.

[0076] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X-1;

[0077] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0078] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0079] In this implementation, the second signal contains ≥2 or 4 levels (preferred), which ensures the number of levels available for clock calibration of the tag and helps improve the accuracy of obtaining level boundaries (symbol boundaries) during detection.

[0080] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0081] In this implementation, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2, which can effectively ensure the buffer time for data reception when the tag is started (that is, when X is 1 / 3 or 1 / 2, under different bandwidths, the duration of the first signal is not shorter than the prescribed duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs)).

[0082] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0083] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0084] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0085] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0086] In this implementation, the introduction of the third signal enables the tag to obtain more energy, which is conducive to maintaining normal communication.

[0087] In one possible design, P2 is equal to 4.

[0088] In this implementation, the number of levels included in the second signal is fixed to 4, which can ensure the number of levels that can be used when the tag performs clock calibration. In addition, it also maximizes the transmission peak rate of the tag.

[0089] In a fourth aspect, the present application provides a communication method. Optionally, the method may be performed by a tag, a component or device applied to the tag (such as a processor, a chip, or a chip system), or a logic module or software that can implement all or part of the tag functions. The tag may be a passive tag or a semi-passive tag. The method includes:

[0090] Receiving a synchronization signal on a first time domain resource and a first frequency domain resource, where the first time domain resource includes M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where both M and N are positive integers;

[0091] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, and the sum of T1 and T2 is equal to the duration of the M OFDM symbols.

[0092] In one possible design, any level included in the first signal is a first level.

[0093] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0094] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0095] In one possible design, the duration of one OFDM symbol is T;

[0096] The duration T1 of the first signal satisfies: T1=M*T*X;

[0097] The duration T2 of the second signal satisfies: T2=M*T*(1-X);

[0098] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0099] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N, and the number P2 of levels included in the second signal is proportional to the value of N.

[0100] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0101] The number P2 of levels included in the second signal satisfies: P2=M*K*N*(1-X);

[0102] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0103] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0104] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0105] In a fifth aspect, the present application provides a communication method. Optionally, the execution subject of the method can be a tag, or a component or device applied to the tag (such as a processor, chip, or chip system, etc.), or a logic module or software that can realize all or part of the tag functions. The tag can be a passive tag or a semi-passive tag. The method includes:

[0106] Receiving a synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, the first frequency domain resource includes N*12 subcarriers, and both M and N are positive integers;

[0107] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

[0108] In one possible design, any level included in the first signal is a first level.

[0109] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0110] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0111] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0112] In one possible design, the duration of one OFDM symbol is T;

[0113] The duration T1 of the first signal satisfies: T1=M*T*X;

[0114] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0115] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0116] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N.

[0117] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0118] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0119] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0120] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0121] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0122] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0123] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0124] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0125] In one possible design, P2 is equal to 4.

[0126] In a sixth aspect, the present application provides a communication method. Optionally, the execution subject of the method may be a tag, or a component or device applied to the tag (such as a processor, chip, or chip system, etc.), or a logic module or software that can implement all or part of the tag functions. The tag may be a passive tag or a semi-passive tag. The method includes:

[0127] Receiving a synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, the first frequency domain resource includes N×12 subcarriers, and both M and N are positive integers;

[0128] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, and the number P2 of levels included in the second signal is a fixed value.

[0129] In one possible design, any level included in the first signal is a first level.

[0130] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0131] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0132] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0133] In one possible design, the duration of one OFDM symbol is T;

[0134] The duration T1 of the first signal satisfies: T1=M*T*X-M*T / K*N;

[0135] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0136] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0137] In one possible design, the sum of the number P1 of levels included in the first signal and 1 is proportional to the value of N.

[0138] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X-1;

[0139] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0140] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0141] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0142] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0143] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0144] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0145] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer. In one possible design, P2 is equal to 4.

[0146] In a seventh aspect, the present application provides a communication device, which may be a network device or a module or chip in a network device. The communication device includes:

[0147] a processing unit, configured to determine a synchronization signal;

[0148] a transceiver unit, configured to send the synchronization signal on a first time domain resource and a first frequency domain resource, where the first time domain resource includes M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where both M and N are positive integers;

[0149] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, and the sum of T1 and T2 is equal to the duration of the M OFDM symbols.

[0150] In one possible design, any level included in the first signal is a first level.

[0151] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0152] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0153] In one possible design, the duration of one OFDM symbol is T;

[0154] The duration T1 of the first signal satisfies: T1=M*T*X;

[0155] The duration T2 of the second signal satisfies: T2=M*T*(1-X);

[0156] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0157] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N, and the number P2 of levels included in the second signal is proportional to the value of N.

[0158] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0159] The number P2 of levels included in the second signal satisfies: P2=M*K*N*(1-X);

[0160] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0161] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0162] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0163] In an eighth aspect, the present application provides a communication device, which may be a network device or a module or chip in a network device. The communication device includes:

[0164] a processing unit, configured to determine a synchronization signal;

[0165] a transceiver unit, configured to send the synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, the first frequency domain resource includes N*12 subcarriers, and both M and N are positive integers;

[0166] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

[0167] In one possible design, any level included in the first signal is a first level.

[0168] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0169] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0170] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0171] In one possible design, the duration of one OFDM symbol is T;

[0172] The duration T1 of the first signal satisfies: T1=M*T*X;

[0173] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0174] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0175] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N.

[0176] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0177] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0178] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0179] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0180] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0181] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0182] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0183] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0184] In one possible design, P2 is equal to 4.

[0185] In a ninth aspect, the present application provides a communication device, which may be a network device or a module or chip in a network device. The communication device includes:

[0186] a processing unit, configured to determine a synchronization signal;

[0187] a transceiver unit, configured to send the synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N×12 subcarriers, where M and N are both positive integers;

[0188] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, and the number P2 of levels included in the second signal is a fixed value.

[0189] In one possible design, any level included in the first signal is a first level.

[0190] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0191] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0192] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0193] In one possible design, the duration of one OFDM symbol is T;

[0194] The duration T1 of the first signal satisfies: T1=M*T*X-M*T / K*N;

[0195] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0196] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0197] In one possible design, the sum of the number P1 of levels included in the first signal and 1 is proportional to the value of N.

[0198] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X-1;

[0199] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0200] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0201] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0202] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0203] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0204] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0205] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0206] In one possible design, P2 is equal to 4.

[0207] In a tenth aspect, the present application provides a communication device, which may be a tag or a module or chip in a tag. The tag may be a passive tag or a semi-passive tag. The communication device includes:

[0208] a transceiver unit, configured to receive a synchronization signal on a first time domain resource and a first frequency domain resource, where the first time domain resource includes M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where both M and N are positive integers;

[0209] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, and the sum of T1 and T2 is equal to the duration of the M OFDM symbols.

[0210] In one possible design, any level included in the first signal is a first level.

[0211] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0212] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0213] In one possible design, the duration of one OFDM symbol is T;

[0214] The duration T1 of the first signal satisfies: T1=M*T*X;

[0215] The duration T2 of the second signal satisfies: T2=M*T*(1-X);

[0216] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0217] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N, and the number P2 of levels included in the second signal is proportional to the value of N.

[0218] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0219] The number P2 of levels included in the second signal satisfies: P2=M*K*N*(1-X);

[0220] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0221] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0222] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0223] In an eleventh aspect, the present application provides a communication device, which may be a tag or a module or chip in a tag. The tag may be a passive tag or a semi-passive tag. The communication device includes:

[0224] a transceiver unit, configured to receive a synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where M and N are both positive integers;

[0225] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

[0226] In one possible design, any level included in the first signal is a first level.

[0227] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0228] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0229] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0230] In one possible design, the duration of one OFDM symbol is T;

[0231] The duration T1 of the first signal satisfies: T1=M*T*X;

[0232] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0233] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0234] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N.

[0235] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0236] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0237] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0238] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0239] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0240] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0241] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0242] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0243] In one possible design, P2 is equal to 4.

[0244] In a twelfth aspect, the present application provides a communication device, which may be a tag or a module or chip in a tag. The tag may be a passive tag or a semi-passive tag. The communication device includes:

[0245] a transceiver unit, configured to receive a synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N×12 subcarriers, where M and N are both positive integers;

[0246] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, and the number P2 of levels included in the second signal is a fixed value.

[0247] In one possible design, any level included in the first signal is a first level.

[0248] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0249] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0250] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0251] In one possible design, the duration of one OFDM symbol is T;

[0252] The duration T1 of the first signal satisfies: T1=M*T*X-M*T / K*N;

[0253] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0254] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0255] In one possible design, the sum of the number P1 of levels included in the first signal and 1 is proportional to the value of N.

[0256] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X-1;

[0257] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0258] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0259] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0260] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0261] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0262] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0263] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer. In one possible design, P2 is equal to 4.

[0264] In a thirteenth aspect, the present application provides a communication device, which includes a processor, and the processor is used to execute a computer program so that the communication device executes any method described in any one of the first to sixth aspects.

[0265] In one possible design, the communication device may be a chip that implements the method of any one of the first to sixth aspects or a device including a chip.

[0266] In one possible design, the communication device further includes a transceiver, and the processor is coupled to the transceiver.

[0267] In one possible design, the communication device further includes a memory. The processor and the memory are coupled, the memory stores a computer program, and the processor is further configured to call the computer program in the memory. For example, the processor and the memory may be integrated.

[0268] In a fourteenth aspect, the present application provides a communication device, which includes a processor, and the processor is used to implement any method described in any one of the first to sixth aspects through a logic circuit or execution code instructions.

[0269] Optionally, the communication device further includes an interface circuit, which is used to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device.

[0270] In the fifteenth aspect, the present application provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is executed by a computer, it implements the method described in any one of the first to sixth aspects.

[0271] In a sixteenth aspect, the present application provides a computer program product. When a computer reads and executes the computer program product, the computer executes any one of the methods described in any one of the first to sixth aspects.

[0272] In the seventeenth aspect, the present application provides a communication system, which includes a communication device for implementing the method described in any one of the first aspect, second aspect, or third aspect above, and a communication device for implementing the method described in any one of the fourth aspect, fifth aspect, or sixth aspect above.

[0273] In the eighteenth aspect, the present application also provides a communication method, wherein the network device is used to execute any method described in the above first aspect, and the tag is used to execute any method described in the above second aspect.

[0274] The beneficial effects of the fourth to eighteenth aspects can be referred to the beneficial effects of the first to third aspects, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0275] FIG1 is a schematic diagram of the architecture of a communication system to which the present application is applicable;

[0276] FIG2 is a schematic diagram of a data-0 signal;

[0277] FIG3 is a schematic diagram of the basic structure of a synchronization signal;

[0278] FIG4 is a flow chart of a communication method according to an embodiment of the present application;

[0279] FIG5 is a schematic diagram of a structure of a synchronization signal provided in an embodiment of the present application;

[0280] FIG6 is a schematic diagram of a DFT-S-OFDM signal processing flow;

[0281] FIG7 is a schematic diagram of a structure of a synchronization signal provided in an embodiment of the present application;

[0282] FIG8 is a schematic diagram of a structure of a synchronization signal provided in an embodiment of the present application;

[0283] FIG9 is a schematic diagram of a structure of a synchronization signal provided in an embodiment of the present application;

[0284] FIG10 is a schematic diagram of a structure of a synchronization signal provided in an embodiment of the present application;

[0285] FIG11 is a schematic structural diagram of a possible communication device provided in an embodiment of the present application;

[0286] FIG12 is a schematic structural diagram of another possible communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0287] The specific embodiments of the present application are further described in detail below with reference to the accompanying drawings.

[0288] The terms "first" and "second" and the like in the specification, claims, and drawings of this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0289] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0290] In this application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three and more than three, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0291] In this application, "sending information to... (e.g., a terminal)" can be understood as the destination of the information being the terminal. This can include sending information to the terminal directly or indirectly. "Receiving information from... (e.g., a terminal)" or "receiving information from... (e.g., a terminal)" can be understood as the source of the information being the terminal, which can include receiving information from the terminal directly or indirectly. The information may undergo necessary processing between the source and destination of the information, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated here.

[0292] First, some terms or concepts involved in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0293] Passive Internet of Things refers to a transmission network including passive (battery free) nodes. Among them, the passive nodes themselves are not equipped with or do not mainly rely on power devices such as batteries, but obtain energy from the environment to support the passive nodes to perceive, transmit and distribute data. In general, passive nodes may include passive tags (passive tags) or semi-passive tags (semi-passive tags), and the transceiver of the passive tag can be excited by the radio frequency field. In the embodiments of the present application, for the sake of simplicity, passive tags or semi-passive tags can be described alternatively as tags. Tags can form a radio-frequency identification (RFID) system together with network devices, and contactless automatic recognition radio frequency technology can be applied in the RFID system.

[0294] RFID technology refers to an automatic identification technology that uses induction, radio waves or microwaves for non-contact two-way communication for the purpose of identification and data exchange. This technology can be used to manage the physical object where the tag is located.

[0295] Figure 1 is a schematic diagram of the architecture of a communication system applicable to this application. The communication system 100 includes an RFID reader / writer (also referred to as a reader / writer, card reader, etc., hereinafter referred to as a reader / writer) 101 and an RFID tag (hereinafter referred to as a tag) 102. The reader / writer 101 and the tag 102 can communicate with each other via radio frequency (RF) signals.

[0296] The reader 101 can transmit an inquiry RF signal. The tag 102 located near the reader 101 can detect the inquiry RF signal sent by the reader 101 and return a response RF signal to the reader 101. The response RF signal can carry the tag 102's own related information.

[0297] The reader / writer 101 can detect and analyze the reply RF signal.

[0298] In the embodiment of the present application, the reader / writer 101 can be understood as an entity on the network side for transmitting or receiving signals, or as a device that communicates with a tag, such as a terminal device, an access network device (such as a base station), or a device with reading and writing functions, etc. For the convenience of description, the specific embodiments below are mainly illustrated by taking network devices as an example.

[0299] The tag 102 in the embodiment of the present application can be a passive tag or a semi-passive tag. If the tag 102 is a passive tag, that is, the tag 102 itself does not have a power source, the tag 102 can obtain energy from the interrogation RF signal. Generally speaking, a passive / semi-passive tag can also be referred to as a passive / semi-passive Internet of Things (IoT) device, which can be regarded as a terminal, such as a passive terminal device, a passive A-IoT terminal device, a semi-passive terminal device, a semi-passive A-IoT terminal device, or a terminal device with backscatter (carrier) capability, etc. Among them:

[0300] Passive tags do not contain batteries. When out of the reader's range, the tag is passive. When within range, it draws power from the RF energy emitted by the reader. Passive tags generally use reflection modulation to transmit tag information to the reader. The practical range of passive tags is approximately 10 centimeters to several meters. While lightweight and compact, they have a long service life, but their transmission distance is limited and require a high reader / writer transmission power and low transponder operating circuit power consumption.

[0301] The battery within a semi-passive tag only provides auxiliary support for the voltage required to maintain data within the tag or the operation of the tag chip, and only powers the tag circuits, which consume very little power themselves. Before the tag enters the operating state, it remains dormant, equivalent to a passive tag. The tag's internal battery consumes very little energy, allowing the battery to remain effective for several years, or even up to 10 years. When the tag enters the reader's readout area, it is stimulated by the reader's RF signal. When the tag enters the operating state, the energy supply for information exchange between the tag and the reader is primarily the RF energy supplied by the reader (reflection modulation). The tag's internal battery primarily compensates for the insufficient RF field strength at the tag's location; the energy within the tag's battery is not converted into RF energy.

[0302] It's understandable that tags can be categorized in other ways: active, passive, and semi-active based on their modulation methods. They can be divided into read-only and read-write tags based on whether the stored information can be rewritten. And they can be categorized into credit card tags, linear tags, paper tags, glass tube tags, circular tags, and special-purpose shaped tags based on their packaging.

[0303] It should be understood that FIG1 exemplarily shows a reader 101 and a tag 102. In the architecture of FIG1 , a reader 101 can communicate with multiple tags 102, and the communication system 100 can include multiple readers 101. This embodiment of the present application does not limit this.

[0304] Currently, the basic structure of the synchronization signal sent by the RFID reader to the tag is delimiter+data-0+RTcal signal.

[0305] Delimiter signal: The delimiter signal is a delimiter. Before the delimiter, the tag receives a continuous high-level signal. The delimiter signal is a low-level signal that lasts for a period of time. When the tag detects a low-level signal that lasts for a period of time, it knows that a time calibration signal will arrive later. During the delimiter reception phase, the tag gradually starts to receive subsequent signals.

[0306] Data-0 signal: The data-0 signal is the signal of bit 0 after PIE encoding. The structure of the data-0 signal is a high level + low level signal, with a total duration of 1 terabyte, where the high level and low level each occupy 0.5 terabytes, as shown in Figure 2. When the tag detects data-0, it can detect the duration of the high and low levels in data-0 through the rising or falling edges between the levels.

[0307] RTcal signal: The total duration of the RTcal signal is the duration corresponding to the data-0 signal plus the duration corresponding to the data-1 signal (the signal after bit 1 is PIE-encoded). The total duration ranges from 2.5Tari ≤ RTcal ≤ 3.0Tari. Therefore, by subtracting the duration of the data-0 signal from the total duration of the RTcal signal, the duration of the data-1 signal is 1.5Tari ≤ the duration of the data-1 signal ≤ 2.0Tari. The structure of the data-1 signal is still a high level + low level signal, where the low level still occupies 0.5Tari. Therefore, the high level in data-1 occupies 1Tari ≤ The duration of the high level contained in the data-1 signal ≤ 1.5Tari, which is 2 to 3 times the duration of the high level in data-0. For example, if the high-level signal in data-1 lasts for 1.5 Tari, and the high-level signal of 0.5 Tari is quantized into the digital signal symbol {1}, and the low-level signal of 0.5 Tari is quantized into the digital signal symbol {0}, then the digital signal corresponding to data-0 can be represented as {10}, and the digital signal corresponding to data-1 can be represented as {1110}. This can also be understood as bit 0 becoming the symbol {10} after PIE encoding, and bit 1 becoming the symbol {1110} after PIE encoding. After detecting the RTcal signal, the tag can detect the duration of the high and low levels in data-1 based on the rising or falling edges between the levels (this information is already obtained when detecting the data-0 signal). Figure 3 shows the basic structure of the synchronization signal.

[0308] Thus, through the data-0 signal and the RTcal signal, the tag effectively obtains the level duration of data-0 and data-1, and obtains the signal clock boundary (symbol boundary) information through the rising and falling edges of the signal, which is equivalent to a time calibration process. Therefore, the data-0 signal and the RTcal signal can also be called the time calibration signal of the passive tag.

[0309] From the above introduction, it can be seen that the current tags (i.e. passive tags or semi-passive tags) mainly use the PIE encoding method. The high-level lengths in the coding patterns corresponding to bit 0 and bit 1 are different, and the high level accounts for ≥50% of the total level duration in the entire coding pattern. PIE encoding, which has unequal high-level lengths, can enable the tag to receive more RF energy during data transmission, thereby better maintaining the tag's communication. However, in actual implementation, the tag circuit usually contains an energy storage capacitor, which can store energy to support subsequent communications for a period of time. Therefore, PIE encoding, which enables the tag to receive more high-level energy, is no longer necessary. Furthermore, as described above, PIE encoding has a bit pattern of {10} after encoding bit 0, and a bit pattern of {1110} after encoding bit 1. The bit patterns after encoding are highly similar, and the average code distance between codewords is extremely small. During demodulation at the receiving end, the probability of incorrect decisions is significantly lower than that of Manchester encoding (where the bit pattern after encoding bit 0 is {10} and the bit pattern after encoding bit 1 is {01}). In Manchester encoding, the bit patterns of the codewords are completely opposite, and the average code distance is maximized. Therefore, during demodulation at the receiving end, Manchester encoding significantly outperforms PIE encoding. Furthermore, the high-level duration of Manchester encoding accounts for 50% of the total level duration, which can better meet the tag's RF energy requirements. Furthermore, the current synchronization signal design only considers a downlink signal bandwidth of 12 subcarriers. If the configured downlink signal bandwidth is larger than 12 subcarriers (e.g., 24 or 48 subcarriers), the current synchronization signal design will be incompatible with wider downlink signal bandwidths.

[0310] Based on this, this application proposes a communication method and related apparatus that are compatible with the design of synchronization signals for passive / semi-passive tags under different downlink signal bandwidths, which is conducive to improving communication performance. In addition, the synchronization signals involved in the embodiments of this application use the more performant Manchester encoding method, which is conducive to improving the demodulation performance of the receiving end.

[0311] The communication method and communication device provided by this application are described in detail below:

[0312] Please refer to Figure 4, which is a flow chart of the communication method provided by an embodiment of the present application. As shown in Figure 4, the communication method includes the following steps S401 to S402. The execution subject of the method shown in Figure 4 can be a network device and a tag (i.e., a passive tag or a semi-passive tag, hereinafter referred to as a tag. It should be noted that the tag in the embodiment of the present application can be understood as a terminal), or the execution subject of the method shown in Figure 4 can also be a chip in a network device and a chip in a tag. For the convenience of description, Figure 4 mainly uses the network device and the tag as an example of the execution subject of the method. It should be noted that Figure 4 is a schematic flow chart of an embodiment of the method of the present application, showing the detailed communication steps or operations of the method, but these steps or operations are only examples. The embodiment of the present application can also perform other operations or variations of the various operations in Figure 4. In addition, the various steps in Figure 4 can be performed in a different order from that presented in Figure 4, and it is possible that not all operations in Figure 4 need to be performed. Among them:

[0313] S401: The network device determines a synchronization signal.

[0314] Among them, the synchronization signal can also be called the synchronization signal of the passive tag, or the leading signal, or the leading signal of the data signal, or the leading signal of the passive tag, or the leading signal of the passive tag data signal, etc. These names are just examples. In the specific implementation, it can also be other names. This application does not make specific limitations on this.

[0315] S402: The network device sends the synchronization signal to the tag on a first time domain resource and a first frequency domain resource. Correspondingly, the tag receives the synchronization signal from the network device on the first time domain resource and the first frequency domain resource.

[0316] Here, the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and preferably, the value of M is equal to 1. The first frequency domain resource includes N*12 subcarriers, or is described as the first frequency domain resource including N resource blocks (RBs). Wherein, M and N are both positive integers, and preferably, M is fixed to 1.

[0317] It should be understood that the modulation mode of the synchronization signal involved in the embodiment of the present application can be on-off keying (OOK) or binary amplitude shift keying (2ASK), so all descriptions of "OOK" in this article can also be replaced with "2ASK". For the convenience of understanding, the following text is mainly explained with the expression of OOK. Among them, the synchronization signal includes a first signal and a second signal, where the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal (that is, if the first signal exists, it means that the second signal is transmitted immediately after the transmission of the first signal is completed, and "immediately exists" here means that there is no time interval (gap) between the first signal and the second signal), or it can be described as the first signal indicating that there is a transmission of the second signal after the first signal, or it can be understood that the first signal is a signal between the energy signal and the second signal. The second signal is used for time calibration, and here "time calibration" has two functions of "determining the duration of the unit level / 1 level" and "determining the time boundary of the data signal". Generally speaking, there is a transmission of the data signal immediately after the transmission of the second signal is completed. It should be noted that the first signal may also be referred to as a delimiter signal or a delimiter or a passive tag delimiter, etc., and the second signal may also be referred to as a time calibration signal or a calibration signal or a symbol synchronization signal or a level calibration signal, etc., and this application does not limit this. Optionally, the first signal may also be a part of the delimiter signal. The levels involved in this application are sometimes also referred to as OOK chips, OOK symbols, or OOK segments, etc., and this embodiment of the application does not specifically limit this.

[0318] It should be noted that, with respect to the design of the first signal and the second signal in the synchronization signal, this application mainly proposes three possible implementation methods, which will be described below respectively.

[0319] Method 1:

[0320] In the following embodiment, a synchronization signal is designed to include a first signal and a second signal, wherein the first time domain resource used to transmit the synchronization signal includes M OFDM symbols (or described as the duration of the first time domain resource being equal to the duration of M OFDM symbols), or, it is understood that the sum of the durations of the first signal and the second signal is equal to the duration of M OFDM symbols.

[0321] Exemplarily, any level included in the first signal can be the first level, that is, the first signal is an all-{0} (or all-low-level) signal. Optionally, the first signal can also be a signal with a predefined / preset pattern, for example, the first signal can be a signal with a combined pattern of {01} and {10}, etc., and this application does not impose any restrictions on this. It should be understood that when the first signal is an all-low-level signal, this design of the first signal can minimize confusion between the first signal and the subsequent second signal and data signal, which is beneficial to improving demodulation performance. Therefore, the following mainly uses the example of the first signal being an all-low-level signal for schematic description.

[0322] The second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, that is, the second signal is a signal with an equal number of {0} and {1} (or the number of low levels is equal to the number of high levels). The second level is higher than the first level, and the second level can also be called a high level, or OOK symbol {1}, or OOK chip {1}. The first level can also be called a low level, or OOK symbol {0}, or OOK chip {0}, etc., which is not specifically limited in the embodiments of the present application.

[0323] Exemplarily, the second signal may be a signal with a predefined / preset pattern. For example, the second signal may be a signal with a combination pattern of {01} and {10}, such as {01100110} or {01011010}. Furthermore, the pattern of the second signal may be another pattern satisfying the requirement that the number of first levels is equal to the number of second levels, such as {01101010} or {10010101}, etc. This application does not impose any limitation on this.

[0324] Exemplarily, the second signal may be one of a plurality of predefined / preset pattern signals, wherein different preset patterns may indicate different subcarrier spacings of the data signal, or different preset patterns may indicate different CP lengths of the data signal. For example, the second signal may be one of two predefined pattern signals. Taking the two predefined patterns {01100110} and {10011001} as an example, when the preset pattern of the second signal is {01100110}, it may indicate that the subcarrier spacing of the data signal is 15 kHz; when the preset pattern of the second signal is {10011001}, it may indicate that the subcarrier spacing of the data signal is 30 kHz. Alternatively, when the preset pattern of the second signal is {01100110}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 15 kHz; and when the preset pattern of the second signal is {10011001}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 30 kHz.

[0325] It should be understood that, in addition to the number of first levels contained in the second signal of the present application being equal to the number of second levels, the second signal may also satisfy the following conditions: any adjacent level of the first level included in the second signal may be the second level, and any adjacent level of the second level included in the second signal may be the first level. For example, in one case, the first level in the second signal is the first level, and the last level of the second signal is the second level, that is, the second signal may be a signal in which {0} and {1} appear alternately, for example, the second signal is {010101}. For another example, in another case, the first level in the second signal is the second level, and the last level of the second signal is the first level, that is, the second signal may also be a signal in which {1} and {0} appear alternately, for example, {101010}. Preferably, the second signal is a signal in which {1} and {0} appear alternately.

[0326] Exemplarily, the second signal may be one of a signal in which {0} and {1} appear alternately and a signal in which {1} and {0} appear alternately, for example, one of {010101} and {101010}. Different forms of the second signal may indicate different subcarrier spacings or different CP lengths of the data signal. For example, when the preset pattern of the second signal is {010101}, it may indicate that the subcarrier spacing of the data signal is 15 kHz; when the preset pattern of the second signal is {101010}, it may indicate that the subcarrier spacing of the data signal is 30 kHz. Alternatively, when the preset pattern of the second signal is {010101}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 15 kHz; and when the preset pattern of the second signal is {101010}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 30 kHz.

[0327] It should be noted that, in the present application, the duration of the second level is equal to the duration of the first level.

[0328] Optionally, the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, that is, the duration T1 of the first signal and the duration T2 of the second signal do not change with the value of N, and the sum of the duration T1 of the first signal and the duration T2 of the second signal is equal to the duration of M OFDM symbols, that is, T1+T2=M*T. Here, T represents the duration of an OFDM symbol, or the duration of an OFDM symbol before a cyclic prefix (CP) is added. Generally speaking, the duration of an OFDM symbol is the inverse of the subcarrier spacing. For example, when the subcarrier spacing is equal to 15kHz, the duration of an OFDM symbol is 1 / 15kHz=66.6us. For another example, when the subcarrier spacing is equal to 30kHz, the duration of an OFDM symbol is 1 / 30kHz=33.3us.

[0329] Optionally, the duration T1 of the first signal may satisfy: T1 = M*T*X, and the duration T2 of the second signal may satisfy: T2 = M*T*(1-X), where 0 < X ​​< 1. It should be understood that, when M = 1, the value of X is associated with the subcarrier spacing. For example, when M is equal to 1 and K is equal to 6, if the subcarrier spacing is 15 kHz, then X = 1 / 3, because the duration of the first signal must not be shorter than the duration specified for the passive tag delimiter (for example, the delimiter duration is not less than 12.5 μs); when M is equal to 1 and K is equal to 6, if the subcarrier spacing is 30 kHz, then X = 1 / 2, because the duration of the first signal must not be shorter than the duration specified for the passive tag delimiter (for example, the delimiter duration is not less than 12.5 μs). Here, K is the number of levels included in one OFDM symbol when N is equal to 1 (that is, K is the number of levels included in one OFDM symbol when the first frequency domain resource includes 12 subcarriers). When N is greater than 1, the number of levels included in one OFDM symbol is K*N. It should be noted that when M is equal to 1, K is equal to 6, and the subcarrier spacing is 15kHz, X=1 / 3 is the preferred solution, and X=1 / 2 is the second preferred solution; when M is equal to 1, K is equal to 6, and the subcarrier spacing is 30kHz, X=1 / 2 is the preferred solution. For the convenience of description, for method one, the following mainly takes X=1 / 3 when M is equal to 1, K is equal to 6, and the subcarrier spacing is 15kHz as an example for schematic explanation.

[0330] Optionally, the number of levels P1 included in the first signal is proportional to the value of N, and the number of levels P2 included in the second signal is proportional to the value of N. Exemplarily, the number of levels P1 included in the first signal may satisfy: P1 = M*K*N*X, and the number of levels P2 included in the second signal may satisfy: P2 = M*K*N*(1-X). Wherein, 0 < X ​​< 1, K is the number of levels included in an OFDM symbol when N is equal to 1 (that is, K is the number of levels included in 1 OFDM symbol when the first frequency domain resource includes 12 subcarriers), and when N is greater than 1, the number of levels included in an OFDM symbol is K*N, and K is usually a positive integer. Generally speaking, when M is equal to 1 and X is a fixed value, the ratio of the number of levels P1 included in the first signal to N is K, and the ratio of the number of levels P1 included in the second signal to N is K.

[0331] Optionally, when K is equal to 6 and M is equal to 1, the total number of levels included in the synchronization signal of mode 1 is 6*N.

[0332] Optionally, when K is equal to 6, the number P1 of levels included in the first signal is generally an integer not less than 2 (i.e., P1 ≥ 2, and P is an integer), the number P2 of levels included in the second signal is generally an integer not less than 2 (i.e., P2 ≥ 2, and P is an integer), or the number P2 of levels included in the second signal is an integer not less than 4 (i.e., P2 ≥ 4, and P is an integer). Preferably, the number P2 of levels included in the second signal is greater than or equal to 4. This is because when P2 is not less than 4, the number of rising edges or falling edges of the level that can be used when the tag performs clock calibration can be effectively guaranteed, ensuring that the detection error of the detection level boundary (symbol boundary) is small.

[0333] For ease of understanding, the following text mainly uses M=1, K=6, and X=1 / 3 as an example for exemplary explanation. When the first time domain resource includes 1 OFDM symbol (that is, the duration of the synchronization signal is 1 OFDM symbol), the duration of the first signal is 1 / 3 of the duration of an OFDM symbol, and the number of levels contained in the first signal is 6*N*1 / 3; the duration of the second signal is 2 / 3 of the duration of an OFDM symbol, and the number of levels contained in the second signal is 6*N*2 / 3.

[0334] For example, please refer to Figure 5, which is a schematic diagram of the structure of a synchronization signal provided by an embodiment of the present application. As shown in Figure 5, taking the subcarrier spacing equal to 15kHz as an example, when the duration of the synchronization signal is 1 OFDM symbol (i.e., M=1, equivalent to the duration of the synchronization signal equal to 66.6μs), K=6, and X=1 / 3, if the first signal is an all-{0} signal and the second signal is a signal with alternating {0} and {1} levels, then:

[0335] When N is 1, the first signal contains 2 levels (i.e., the first signal is {00}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz and before adding a CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0336] When N is 2, the number of levels contained in the first signal is 4 (i.e., the first signal is {0000}), and the number of levels contained in the second signal is 8 (i.e., the second signal is {01010101}); when the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0337] When N is equal to 3, the number of levels contained in the first signal is 6 (i.e., the first signal is {000000}), and the number of levels contained in the second signal is 12 (i.e., the second signal is {010101010101}); when the subcarrier spacing is equal to 15 kHz, before adding CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0338] When N is equal to 4, the first signal contains 8 levels (i.e., the first signal is {00000000}), and the second signal contains 16 levels (i.e., the second signal is {0101010101010101}); when the subcarrier spacing is equal to 15 kHz, before adding CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0339] As shown in Figure 5, when the subcarrier spacing is 15 kHz and before adding a CP, the duration of the first signal, T1, is 1 / 3*66.6 μs, or 22.2 μs; the duration of the second signal, T2, is 2 / 3*66.6 μs, or 44.4 μs. The first signal contains 6*N*1 / 3 levels, and the second signal contains 6*N*2 / 3 levels.

[0340] Optionally, in the present application, the network device can specifically adopt the discrete Fourier transform-spreading-orthogonal frequency division multiplexing (DFT-S-OFDM) generation method shown in Figure 6 to process the synchronization signal and then send it, wherein the length of the discrete Fourier transform (DFT) input sequence is N*12, and the pattern of the DFT input sequence is a level pattern composed of all levels contained in the first signal and the second signal, and the number of repetitions of each level is equal to 12 / K. For example, when K is equal to 6, the number of repetitions is equal to 2. Exemplarily, when the duration of the synchronization signal is 1 OFDM symbol (i.e., M=1), when N is equal to 1, the level contained in the first signal is {00}, and the level contained in the second signal is {0101}. By repeating each level in the first signal and the second signal twice (i.e., the number of repetitions of each level is equal to 2), the levels {0000} and {00110011} can be obtained, and the level pattern is {000000110011}, that is, the DFT input sequence is {000000110011}.

[0341] The design based on Method 1 effectively guarantees the performance of synchronization signals in passive IoT systems. The first signal maintains a constant duration across different bandwidths and is no shorter than the specified duration for passive tag delimiters (e.g., a delimiter duration of no less than 12.5 μs). This effectively ensures buffering time for data reception during tag startup. The second signal contains ≥4 levels (preferably), effectively ensuring the number of levels available for tag clock calibration, which improves the accuracy of detecting level boundaries (symbol boundaries) during detection.

[0342] Method 2:

[0343] Under method 2, a design is that the synchronization signal includes a first signal and a second signal, wherein the duration of the first time domain resource used to transmit the synchronization signal is less than or equal to the duration of M OFDM symbols, or, it is understood that the sum of the durations of the first signal and the second signal is less than or equal to the duration of M OFDM symbols.

[0344] Exemplarily, any level included in the first signal can be the first level, that is, the first signal is an all-{0} (or all-low-level) signal. Optionally, the first signal can also be a signal with a predefined / preset pattern, for example, the first signal can be a signal with a combined pattern of {01} and {10}, etc., and this application does not impose any restrictions on this. It should be understood that when the first signal is an all-low-level signal, this design of the first signal can minimize confusion between the first signal and the subsequent second signal and data signal, which is beneficial to improving demodulation performance. Therefore, the following mainly uses the example of the first signal being an all-low-level signal for schematic description.

[0345] The second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, that is, the second signal is a signal with an equal number of {0} and {1} (or the number of low levels is equal to the number of high levels). The second level is higher than the first level, and the second level can also be called a high level, or OOK symbol {1}, or OOK chip {1}. The first level can also be called a low level, or OOK symbol {0}, or OOK chip {0}, etc., which is not specifically limited in the embodiments of the present application.

[0346] For example, the second signal may be a signal of a predefined / preset pattern. For example, the second signal may be a signal of a combination pattern of {01} and {10}, such as {0110} or {1001}. Furthermore, for example, the pattern of the second signal may be another pattern that satisfies the requirement that the number of first levels equals the number of second levels, and this application does not impose any limitation thereto.

[0347] Exemplarily, the second signal may be one of a plurality of predefined / preset pattern signals, wherein different preset patterns may indicate different subcarrier spacings of the data signal, or different preset patterns may indicate different CP lengths of the data signal. For example, the second signal may be one of two predefined pattern signals, and taking the two predefined patterns {0110} and {1001} as an example, when the preset pattern of the second signal is {0110}, it may indicate that the subcarrier spacing of the data signal is 15 kHz, and when the preset pattern of the second signal is {1001}, it may indicate that the subcarrier spacing of the data signal is 30 kHz. Alternatively, when the preset pattern of the second signal is {0110}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 15 kHz, and when the preset pattern of the second signal is {1001}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 30 kHz.

[0348] It should be understood that, in addition to the second signal involved in the present application having the number of first levels equal to the number of second levels, any adjacent level of the first level included in the second signal may be the second level, and any adjacent level of the second level included in the second signal may be the first level. For example, in one case, the first level in the second signal is the first level, and the last level of the second signal is the second level, that is, the second signal may be a signal in which {0} and {1} appear alternately, for example, the second signal is {0101}. For another example, in another case, the first level in the second signal is the second level, and the last level of the second signal is the first level, that is, the second signal may also be a signal in which {1} and {0} appear alternately, for example, {1010}. Preferably, the second signal is a signal in which {1} and {0} appear alternately.

[0349] Exemplarily, the second signal may be one of a signal in which {0} and {1} appear alternately and a signal in which {1} and {0} appear alternately, for example, one of {0101} and {1010}. Different forms of the second signal may indicate different subcarrier spacings or different CP lengths of the data signal. For example, when the preset pattern of the second signal is {0101}, it may indicate that the subcarrier spacing of the data signal is 15 kHz; and when the preset pattern of the second signal is {1010}, it may indicate that the subcarrier spacing of the data signal is 30 kHz. Alternatively, when the preset pattern of the second signal is {0101}, it may indicate that the CP length of the data signal is the CP length corresponding to a subcarrier spacing of 15 kHz; and when the preset pattern of the second signal is {1010}, it may indicate that the CP length of the data signal is the CP length corresponding to a subcarrier spacing of 30 kHz.

[0350] It should be noted that, in the present application, the duration of the second level is equal to the duration of the first level.

[0351] Optionally, the duration T1 of the first signal is a fixed value, that is, the duration T1 of the first signal does not change with the value of N. Optionally, the duration T2 of the second signal is inversely proportional to the value of N.

[0352] Exemplarily, the duration T1 of the first signal may satisfy: T1 = M*T*X, and the duration T2 of the second signal may satisfy: T2 = M*T*(1-X) / N. Here, T represents the duration of an OFDM symbol, or the duration of an OFDM symbol before the CP is added. Generally speaking, the duration of an OFDM symbol is the reciprocal of the subcarrier spacing. For example, when the subcarrier spacing is equal to 15 kHz, the duration of an OFDM symbol is 1 / 15 kHz = 66.6 us. For another example, when the subcarrier spacing is equal to 30 kHz, the duration of an OFDM symbol is 1 / 30 kHz = 33.3 us.

[0353] It should be noted that the above X should satisfy: 0<X<1. It should be understood that when M=1, the value of X is associated with the subcarrier spacing. For example, when M is equal to 1 and K is equal to 6, if the subcarrier spacing is 15kHz, then X=1 / 3, because the duration of the first signal must not be shorter than the duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs); when M is equal to 1 and K is equal to 6, if the subcarrier spacing is 30kHz, then X=1 / 2, because the duration of the first signal must not be shorter than the duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs). Here, K is the number of levels included in an OFDM symbol when N is equal to 1 (that is, K is the number of levels included in one OFDM symbol when the first frequency domain resource includes 12 subcarriers). When N is greater than 1, the number of levels included in one OFDM symbol is K*N. It should be noted that when M is equal to 1, K is equal to 6, and the subcarrier spacing is 15kHz, X = 1 / 3 is the preferred solution, and X = 1 / 2 is the second preferred solution. When M is equal to 1, K is equal to 6, and the subcarrier spacing is 30kHz, X = 1 / 2 is the preferred solution. For the convenience of description, the following mainly uses M equal to 1, K equal to 6, and the subcarrier spacing is 15kHz, and X = 1 / 3 as an example for schematic explanation of method 2.

[0354] Optionally, the number of levels P1 included in the first signal is proportional to the value of N. The number of levels P2 included in the second signal is a fixed value, that is, the number of levels included in the second signal does not change with the value of N. For example, P2 can be any integer not less than 2 or not less than 4. For example, the value of P2 is fixed to 4, which can effectively ensure the number of levels that can be used when the tag performs clock calibration, and ensure the accuracy of obtaining the level boundary (symbol boundary) during detection. Exemplarily, the number of levels P1 included in the first signal can satisfy: P1 = M*K*N*X. Wherein, 0 < X ​​< 1, K is the number of levels included in an OFDM symbol when N is equal to 1 (that is, K is the number of levels included in 1 OFDM symbol when the first frequency domain resource includes 12 subcarriers), and when N is greater than 1, the number of levels included in an OFDM symbol is K*N, and K is usually a positive integer.

[0355] Optionally, when K is equal to 6, the number P1 of levels included in the first signal is generally an integer not less than 2 (ie, P1 ≥ 2, and P is an integer).

[0356] For ease of understanding, the following text mainly uses M=1, K=6, X=1 / 3, and P2=4 as an example for illustrative explanation. When the duration of the first time domain resource is less than or equal to the duration of one OFDM symbol (that is, the duration of the synchronization signal is less than or equal to the duration of one OFDM symbol), the duration of the first signal is 1 / 3 of the duration of one OFDM symbol, and the number of levels contained in the first signal is 6*N*1 / 3; the duration of the second signal is inversely proportional to the value of N, and the number of levels contained in the second signal is fixed at 4.

[0357] For example, please refer to Figure 7, which is another structural diagram of the synchronization signal provided by an embodiment of the present application. As shown in Figure 7, taking the subcarrier spacing equal to 15kHz as an example, when the duration of the synchronization signal is less than or equal to the duration of 1 (i.e., M=1) OFDM symbol (equivalent to the duration of the synchronization signal being less than or equal to 66.6μs), K=6, X=1 / 3, and P2=4, if the first signal is a full {0} signal and the second signal is a signal with alternating {0} and {1} levels, then:

[0358] When N is 1, the first signal contains 2 levels (i.e., the first signal is {00}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz and before adding a CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0359] When N is 2, the first signal contains 4 levels (i.e., the first signal is {0000}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz, before adding a CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 22.2 μs.

[0360] When N is 3, the first signal contains 6 levels (i.e., the first signal is {000000}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz, before adding a CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 14.8 μs.

[0361] When N is 4, the first signal contains 8 levels (i.e., the first signal is {00000000}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz, before adding a CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 11.1 μs.

[0362] As shown in Figure 7, when the subcarrier spacing is 15 kHz and before adding a CP, the duration of the first signal, T1, is 1 / 3 * 66.6 μs, or 22.2 μs. The duration of the second signal is inversely proportional to the value of N. When N is 1, the second signal duration is 44.4 μs; when N is 2, the second signal duration is 22.2 μs; when N is 3, the second signal duration is 14.8 μs; and when N is 4, the second signal duration is 11.1 μs. The number of levels contained in the first signal is 6 * N * 1 / 3, while the number of levels contained in the second signal is fixed at 4.

[0363] Under mode 2, another design is that the synchronization signal includes a first signal, a second signal and a third signal, wherein the duration of the first time domain resource used to transmit the synchronization signal is equal to the duration of M OFDM symbols, or, it is understood that the sum of the durations of the first signal, the second signal and the third signal is equal to the duration of M OFDM symbols.

[0364] The third signal precedes the first signal. That is, the order of the first, second, and third signals in the synchronization signal is {third signal, first signal, second signal}. For example, any level included in the third signal can be the second level, meaning the third signal is all {1} ​​(or all high level) signals. This helps the tag obtain more energy and maintains normal communication.

[0365] It should be understood that since the sum of the durations of the first signal, the second signal, and the third signal is equal to the duration of M OFDM symbols, the duration T3 of the third signal can satisfy: T3 = M*T - T1 - T2. Optionally, the number P3 of levels included in the third signal can satisfy: P3 = M*K*N - P1 - P2. Where K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer. Here, M*K*N is the total number of levels included in the synchronization signal. When K is equal to 6 and M is equal to 1, the total number of levels included in the synchronization signal of this method 2 is 6*N. Therefore, the number P3 of levels included in the third signal satisfies: P3 = 6*N - 6*N*X - P2.

[0366] For example, please refer to Figure 8, which is another structural diagram of the synchronization signal provided by an embodiment of the present application. As shown in Figure 8, taking the subcarrier spacing equal to 15kHz as an example, when the duration of the synchronization signal is equal to the duration of 1 (i.e., M=1) OFDM symbol (equivalent to the duration of the synchronization signal equal to 66.6μs), K=6, X=1 / 3, and P2=4, if the third signal is an all-{1} signal, the first signal is an all-{0} signal, and the second signal is a signal with alternating {0} and {1} levels, then:

[0367] When N is 1, the third signal contains 0 levels (i.e., the third signal does not exist), the first signal contains 2 levels (i.e., the first signal is {00}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz and before adding a CP, the duration T3 of the third signal is 0 μs, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0368] When N is 2, the third signal contains 4 levels (i.e., the third signal is {1111}), the first signal contains 4 levels (i.e., the first signal is {0000}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz, before adding a CP, the duration T3 of the third signal is 22.2 μs, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 22.2 μs.

[0369] When N is equal to 3, the number of levels contained in the third signal is 8 (i.e., the third signal is {11111111}), the number of levels contained in the first signal is 6 (i.e., the first signal is {000000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}); when the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T3 of the third signal is 29.6 μs, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 14.8 μs.

[0370] When N is equal to 4, the number of levels contained in the third signal is 12 (i.e., the third signal is {111111111111}), the number of levels contained in the first signal is 8 (i.e., the first signal is {00000000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}); when the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T3 of the third signal is 33.3 μs, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 11.1 μs.

[0371] As shown in Figure 8, when the subcarrier spacing is 15 kHz and before adding a CP, the duration of the first signal, T1, equals 1 / 3 the duration of an OFDM symbol, or 22.2 μs. The duration of the second signal is inversely proportional to the value of N. When N is 1, the second signal duration is 44.4 μs; when N is 2, the second signal duration is 22.2 μs; when N is 3, the second signal duration is 14.8 μs; and when N is 4, the second signal duration is 11.1 μs. The duration of the third signal, T3, equals 66.6 μs - T1 - T2. The first signal contains 6 * N * 1 / 3 levels, the second signal contains a fixed number of 4 levels, and the third signal contains P3, which equals 6 * N - 6 * N * 1 / 3 - 4 levels.

[0372] Optionally, in the present application, the network device can specifically use the DFT-S-OFDM generation method shown in Figure 6 to process the synchronization signal and then send it, wherein the length of the DFT input sequence is N*12, the pattern of the DFT input sequence is the third signal, and the first signal and the second signal contain all levels of each level. The number of repetitions is equal to 12 / K, for example, when K is equal to 6, the number of repetitions is equal to 2. Exemplarily, when the duration of the synchronization signal is 1 OFDM symbol (i.e., M=1), when N is equal to 2, the level included in the third signal is {1111}, the level of the first signal is {0000}, and the level included in the second signal is {0101}. By repeating each level in the third signal, the first signal, and the second signal once (i.e., the number of repetitions of each level is equal to 2), the levels {11111111}, {00000000}, and {00110011} can be obtained, that is, the DFT input sequence is {1111111110000000000110011}.

[0373] The design of method 2 effectively guarantees the performance of synchronization signals in passive IoT systems. The first signal maintains a constant duration across different bandwidths and is no shorter than the specified duration of a passive tag delimiter (e.g., a delimiter duration of no less than 12.5 μs). Therefore, the first signal acts as a delimiter, effectively ensuring buffer time for data reception during tag startup. The second signal contains a fixed number of levels equal to four, effectively ensuring the number of levels available for tag clock calibration while maximizing the peak transmission rate of the (passive or semi-passive) tag.

[0374] Method 3:

[0375] Under mode three, a design is that the synchronization signal includes a first signal and a second signal, wherein the duration of the first time domain resource used to transmit the synchronization signal is less than or equal to the duration of M OFDM symbols, or, it is understood that the sum of the durations of the first signal and the second signal is less than or equal to the duration of M OFDM symbols.

[0376] Exemplarily, any level included in the first signal can be the first level, that is, the first signal is an all-{0} (or all-low-level) signal. Optionally, the first signal can also be a signal with a predefined / preset pattern, for example, the first signal can be a signal with a combined pattern of {01} and {10}, etc., and this application does not impose any restrictions on this. It should be understood that when the first signal is an all-low-level signal, this design of the first signal can minimize confusion between the first signal and the subsequent second signal and data signal, which is beneficial to improving demodulation performance. Therefore, the following mainly uses the example of the first signal being an all-low-level signal for schematic description.

[0377] The second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, that is, the second signal is a signal with an equal number of {0} and {1} (or the number of low levels is equal to the number of high levels). The second level is higher than the first level, and the second level can also be called a high level, or OOK symbol {1}, or OOK chip {1}. The first level can also be called a low level, or OOK symbol {0}, or OOK chip {0}, etc., which is not specifically limited in the embodiments of the present application.

[0378] Exemplarily, the second signal may be a signal having a predefined / preset pattern. Optionally, the second signal may also satisfy the following requirement: the first level in the second signal may be the first level. For example, the second signal may be a signal having a combined pattern of {01} and {10}, such as {0110} or {1001}, etc., which is not limited in this application.

[0379] Exemplarily, the second signal may be one of a plurality of predefined / preset pattern signals, wherein different preset patterns may indicate different subcarrier spacings of the data signal, or different preset patterns may indicate different CP lengths of the data signal. For example, the second signal may be one of two predefined pattern signals, and taking the two predefined patterns {0110} and {1001} as an example, when the preset pattern of the second signal is {0110}, it may indicate that the subcarrier spacing of the data signal is 15 kHz, and when the preset pattern of the second signal is {1001}, it may indicate that the subcarrier spacing of the data signal is 30 kHz. Alternatively, when the preset pattern of the second signal is {0110}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 15 kHz, and when the preset pattern of the second signal is {1001}, it may indicate that the CP length of the data signal is the CP length corresponding to the subcarrier spacing of 30 kHz.

[0380] As another example, in addition to the number of first levels contained in the second signal of the present application being equal to the number of second levels, the second signal may also satisfy the following conditions: any level adjacent to a first level included in the second signal may be the second level, and any level adjacent to a second level included in the second signal may be the first level. Optionally, the second signal may also satisfy the following conditions: the first level in the second signal may be the first level, and the last level in the second signal may be the second level. For example, the second signal may be a signal in which {0} and {1} appear alternately, for example, the second signal is {0101}.

[0381] Preferably, the second signal is a signal in which {0} and {1} appear alternately.

[0382] It should be noted that, in the present application, the duration of the second level is equal to the duration of the first level.

[0383] Optionally, the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, that is, the sum of the duration T1 of the first signal and the duration of one first level does not change with the value of N. Optionally, the duration T2 of the second signal is inversely proportional to the value of N.

[0384] Exemplarily, the duration T1 of the first signal may satisfy: T1 = M*T*X - M*T / K*N, where M*T / K*N represents the duration of the unit level. The duration T2 of the second signal may satisfy: T2 = M*T*(1-X) / N. Here T represents the duration of an OFDM symbol, or the duration of an OFDM symbol before the CP is added. Generally speaking, the duration of an OFDM symbol is the reciprocal of the subcarrier spacing. For example, when the subcarrier spacing is equal to 15kHz, the duration of an OFDM symbol is 1 / 15kHz = 66.6us. For another example, when the subcarrier spacing is equal to 30kHz, the duration of an OFDM symbol is 1 / 30kHz = 33.3us.

[0385] It should be noted that the above X should satisfy: 0<X<1. It should be understood that when M=1, the value of X is associated with the subcarrier spacing. For example, when M is equal to 1 and K is equal to 6, if the subcarrier spacing is 15kHz, then X=1 / 3, because the duration of the first signal must not be shorter than the duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs); when M is equal to 1 and K is equal to 6, if the subcarrier spacing is 30kHz, then X=1 / 2, because the duration of the first signal must not be shorter than the duration of the passive tag delimiter (for example, the delimiter duration is not less than 12.5μs). Here, K is the number of levels included in an OFDM symbol when N is equal to 1 (that is, K is the number of levels included in one OFDM symbol when the first frequency domain resource includes 12 subcarriers). When N is greater than 1, the number of levels included in one OFDM symbol is K*N. It should be noted that when M is equal to 1, K is equal to 6, and the subcarrier spacing is 15kHz, X = 1 / 3 is the preferred solution, and X = 1 / 2 is the second preferred solution. When M is equal to 1, K is equal to 6, and the subcarrier spacing is 30kHz, X = 1 / 2 is the preferred solution. For the convenience of description, the following mainly uses M equal to 1, K equal to 6, and the subcarrier spacing is 15kHz, and X = 1 / 2 as an example for schematic explanation of method 3.

[0386] Optionally, the sum of the number of levels P1 and 1 included in the first signal is proportional to the value of N. The number of levels P2 included in the second signal is a fixed value, that is, the number of levels included in the second signal does not change with the value of N. For example, P2 can be any integer not less than 2 or not less than 4. For example, the value of P2 is fixed to 4, which can effectively ensure the number of levels that can be used when the tag performs clock calibration, and ensure the accuracy of obtaining the level boundary (symbol boundary) during detection. Exemplarily, the number of levels P1 included in the first signal can satisfy: P1 = M*K*N*X-1. Wherein, 0<X<1, K is the number of levels included in an OFDM symbol when N is equal to 1 (that is, K is the number of levels included in 1 OFDM symbol when the first frequency domain resource includes 12 subcarriers), and when N is greater than 1, the number of levels included in an OFDM symbol is K*N, and K is usually a positive integer.

[0387] Optionally, when K is equal to 6, the number P1 of levels included in the first signal is generally an integer not less than 2 (ie, P1 ≥ 2, and P is an integer).

[0388] For ease of understanding, the following text mainly uses M=1, K=6, X=1 / 2, and P2=4 as an example for exemplary explanation. When the first time domain resource includes 1 OFDM symbol (that is, the duration of the synchronization signal is 1 OFDM symbol), the sum of the duration of the first signal and the duration of the first level in the second signal is 1 / 2 of the duration of an OFDM symbol, and the number of levels contained in the first signal is 6*N*1 / 2-1; the duration of the second signal is inversely proportional to the value of N, and the number of levels contained in the second signal is fixed at 4.

[0389] For example, please refer to Figure 9, which is another structural diagram of the synchronization signal provided by an embodiment of the present application. As shown in Figure 9, taking the subcarrier spacing equal to 15kHz as an example, when the duration of the synchronization signal is less than or equal to the duration of 1 (i.e., M=1) OFDM symbol (equivalent to the duration of the synchronization signal being less than or equal to 66.6μs), K=6, X=1 / 2, and P2=4, if the first signal is a full {0} signal and the second signal is a signal with alternating {0} and {1} levels, then:

[0390] When N is 1, the first signal contains 2 levels (i.e., the first signal is {00}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz and before adding a CP, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0391] When N is 2, the number of levels contained in the first signal is 5 (i.e., the first signal is {00000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}). When the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T1 of the first signal is 27.7 μs, and the duration T2 of the second signal is 22.2 μs.

[0392] When N is 3, the number of levels contained in the first signal is 8 (i.e., the first signal is {00000000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}). When the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T1 of the first signal is 29.6 μs, and the duration T2 of the second signal is 14.8 μs.

[0393] When N is 4, the first signal contains 11 levels (i.e., the first signal is {00000000000}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz, before adding a CP, the duration T1 of the first signal is 30.5 μs, and the duration T2 of the second signal is 11.1 μs.

[0394] As shown in Figure 9, when the subcarrier spacing is 15 kHz and before adding a CP, the duration of the first signal, T1, equals 1 / 2*66.6μs - 66.6μs / 6*N. In other words, the sum of the duration of the first signal, T1, and the duration of a first level in the second signal is a fixed value of 33.3μs. The duration of the second signal is inversely proportional to the value of N. When N is 1, the second signal duration is 44.4μs; when N is 2, the second signal duration is 22.2μs; when N is 3, the second signal duration is 14.8μs; and when N is 4, the second signal duration is 11.1μs. The number of levels contained in the first signal is 6*N*1 / 2 - 1, while the number of levels contained in the second signal is fixed at 4.

[0395] Under mode three, another design is that the synchronization signal includes a first signal, a second signal and a third signal, wherein the duration of the first time domain resource used to transmit the synchronization signal is equal to the duration of M OFDM symbols, or, it is understood that the sum of the durations of the first signal, the second signal and the third signal is equal to the duration of M OFDM symbols.

[0396] The third signal precedes the first signal. That is, the order of the first, second, and third signals in the synchronization signal is {third signal, first signal, second signal}. For example, any level included in the third signal can be the second level, meaning the third signal is all {1} ​​(or all high level) signals. This helps the tag obtain more energy and maintains normal communication.

[0397] It should be understood that since the sum of the durations of the first signal, the second signal, and the third signal is equal to the duration of M OFDM symbols, the duration T3 of the third signal can satisfy: T3 = M*T - T1 - T2. Optionally, the number P3 of levels included in the third signal can satisfy: P3 = M*K*N - P1 - P2. Where K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer. Here, M*K*N is the total number of levels included in the synchronization signal. When K is equal to 6 and M is equal to 1, the total number of levels included in the synchronization signal of this method three is 6*N. Therefore, the number P3 of levels included in the third signal satisfies: P3 = 6*N - 6*N*X - P2.

[0398] For example, please refer to Figure 10, which is another structural diagram of the synchronization signal provided by an embodiment of the present application. As shown in Figure 10, taking the subcarrier spacing equal to 15kHz as an example, when the duration of the synchronization signal is equal to the duration of 1 (i.e., M=1) OFDM symbol (equivalent to the duration of the synchronization signal being equal to 66.6μs), K=6, X=1 / 2, and P2=4, if the third signal is an all-{1} signal, the first signal is an all-{0} signal, and the second signal is a signal in which the {0} and {1} levels alternate, then:

[0399] When N is 1, the third signal contains 0 levels (i.e., the third signal does not exist), the first signal contains 2 levels (i.e., the first signal is {00}), and the second signal contains 4 levels (i.e., the second signal is {0101}). When the subcarrier spacing is 15 kHz and before adding a CP, the duration T3 of the third signal is 0 μs, the duration T1 of the first signal is 22.2 μs, and the duration T2 of the second signal is 44.4 μs.

[0400] When N is 2, the number of levels contained in the third signal is 3 (i.e., the third signal is {111}), the number of levels contained in the first signal is 5 (i.e., the first signal is {00000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}); when the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T3 of the third signal is 16.7 μs, the duration T1 of the first signal is 27.7 μs, and the duration T2 of the second signal is 22.2 μs.

[0401] When N is equal to 3, the number of levels contained in the third signal is 6 (i.e., the third signal is {111111}), the number of levels contained in the first signal is 8 (i.e., the first signal is {00000000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}); when the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T3 of the third signal is 22.2 μs, the duration T1 of the first signal is 29.6 μs, and the duration T2 of the second signal is 14.8 μs.

[0402] When N is equal to 4, the number of levels contained in the third signal is 9 (i.e., the third signal is {111111111}), the number of levels contained in the first signal is 11 (i.e., the first signal is {00000000000}), and the number of levels contained in the second signal is 4 (i.e., the second signal is {0101}); when the subcarrier spacing is equal to 15 kHz, before adding the CP, the duration T3 of the third signal is 25 μs, the duration T1 of the first signal is 30.5 μs, and the duration T2 of the second signal is 11.1 μs.

[0403] As shown in Figure 10, when the subcarrier spacing is 15 kHz and before adding a CP, the duration of the first signal, T1, equals 1 / 2 * 66.6 μs - 66.6 μs / 6 * N. In other words, the sum of the duration of the first signal, T1, and the duration of a first level in the second signal is a fixed value of 33.3 μs. The duration of the second signal is inversely proportional to the value of N. When N is 1, the second signal duration is 44.4 μs; when N is 2, the second signal duration is 22.2 μs; when N is 3, the second signal duration is 14.8 μs; and when N is 4, the second signal duration is 11.1 μs. The duration of the third signal, T3, equals 66.6 μs - T1 - T2. The number of levels in the first signal is 6 * N * 1 / 2 - 1, while the number of levels in the second signal is fixed at 4. The number of levels in the third signal, P3, equals 6 * N - (6 * N * 1 / 2 - 1) - 4.

[0404] Optionally, in the present application, the network device can specifically use the DFT-S-OFDM generation method shown in Figure 6 to process the synchronization signal and then send it, wherein the length of the DFT input sequence is N*12, the pattern of the DFT input sequence is the third signal, and the first signal and the second signal contain all levels of each level. The number of repetitions is equal to 12 / K, for example, when K is equal to 6, the number of repetitions is equal to 2. Exemplarily, when the duration of the synchronization signal is 1 OFDM symbol (i.e., M=1), when N is equal to 2, the level included in the third signal is {111}, the level of the first signal is {00000}, and the level included in the second signal is {0101}. By repeating each level in the third signal, the first signal and the second signal once (i.e., the number of repetitions of each level is equal to 2), the levels {111111}, {0000000000} and {00110011} can be obtained, that is, the DFT input sequence is {111111000000000000110011}.

[0405] The design based on method three effectively guarantees the performance of synchronization signals in passive IoT systems. The duration of the first signal plus the duration of the first level of the second signal remain constant across different bandwidths and are no shorter than the specified duration of the passive tag delimiter (for example, the delimiter duration is no less than 12.5 μs). Therefore, the first level of the first signal plus the second signal is equivalent to the delimiter signal, effectively ensuring buffer time for data reception when the tag starts. The number of levels contained in the second signal is fixed at four, effectively ensuring the number of levels available for clock calibration while maximizing the peak transmission rate of the (passive or semi-passive) tag.

[0406] The embodiments of the present application are compatible with the design of synchronization signals for passive tags under different downlink signal bandwidths, which is beneficial to improving communication performance. In addition, the design of synchronization signals for passive tags in the present application can also adapt to Manchester encoding, that is, the high and low level durations of bits 0 and 1 remain equal, which is beneficial to improving demodulation performance.

[0407] The communication device provided in this application will be described in detail below with reference to FIG. 11 and FIG. 12 .

[0408] It is understood that in order to implement the functions in the above embodiments, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. It should be readily apparent to those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a manner driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0409] Figures 11 and 12 are schematic diagrams of the structures of possible communication devices provided by embodiments of the present application. These communication devices can be used to implement the functions of the network device or (passive or semi-passive) tag in the above-mentioned method embodiment, and therefore can also achieve the beneficial effects possessed by the above-mentioned method embodiment. In the embodiments of the present application, these communication devices can be network devices or (passive or semi-passive) tags, or can be components or devices (such as processors, chips, or chip systems, etc.) applied to network devices or (passive or semi-passive) tags, or can be logic modules or software that can implement all or part of the network device or (passive or semi-passive) tag functions.

[0410] As shown in Figure 11, the communication device 1100 includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is used to implement the functions of the network device or (passive or semi-passive) tag in the method embodiment shown in Figure 4 above.

[0411] When the communication device 1100 is used to implement the functions of the network device in the method embodiment shown in FIG4 :

[0412] In one design:

[0413] The processing unit 1110 is configured to determine a synchronization signal;

[0414] The transceiver unit 1120 is configured to send the synchronization signal on a first time domain resource and a first frequency domain resource, where the first time domain resource includes M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where M and N are both positive integers;

[0415] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, and the sum of T1 and T2 is equal to the duration of the M OFDM symbols.

[0416] In one possible design, any level included in the first signal is a first level.

[0417] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0418] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0419] In one possible design, the duration of one OFDM symbol is T;

[0420] The duration T1 of the first signal satisfies: T1=M*T*X;

[0421] The duration T2 of the second signal satisfies: T2=M*T*(1-X);

[0422] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0423] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N, and the number P2 of levels included in the second signal is proportional to the value of N.

[0424] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0425] The number P2 of levels included in the second signal satisfies: P2=M*K*N*(1-X);

[0426] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0427] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0428] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0429] In another design:

[0430] The processing unit 1110 is configured to determine a synchronization signal;

[0431] The transceiver unit 1120 is configured to send the synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where M and N are both positive integers;

[0432] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

[0433] In one possible design, any level included in the first signal is a first level.

[0434] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0435] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0436] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0437] In one possible design, the duration of one OFDM symbol is T;

[0438] The duration T1 of the first signal satisfies: T1=M*T*X;

[0439] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0440] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0441] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N.

[0442] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0443] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0444] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0445] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0446] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0447] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0448] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0449] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0450] In one possible design, P2 is equal to 4.

[0451] In yet another design:

[0452] The processing unit 1110 is configured to determine a synchronization signal;

[0453] The transceiver unit 1120 is configured to send the synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N×12 subcarriers, where M and N are both positive integers;

[0454] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, and the number P2 of levels included in the second signal is a fixed value.

[0455] In one possible design, any level included in the first signal is a first level.

[0456] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0457] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0458] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0459] In one possible design, the duration of one OFDM symbol is T;

[0460] The duration T1 of the first signal satisfies: T1=M*T*X-M*T / K*N;

[0461] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0462] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0463] In one possible design, the sum of the number P1 of levels included in the first signal and 1 is proportional to the value of N.

[0464] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X-1;

[0465] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0466] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0467] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0468] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0469] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0470] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0471] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0472] In one possible design, P2 is equal to 4.

[0473] When the communication device 1100 is used to implement the function of the (passive or semi-passive) tag in the method embodiment shown in FIG4 :

[0474] In one design:

[0475] The transceiver unit 1120 is configured to receive a synchronization signal on a first time domain resource and a first frequency domain resource, where the first time domain resource includes M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where both M and N are positive integers.

[0476] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the duration T2 of the second signal are both fixed values, and the sum of T1 and T2 is equal to the duration of the M OFDM symbols.

[0477] The processing unit 1110 is configured to parse the synchronization signal.

[0478] In one possible design, any level included in the first signal is a first level.

[0479] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0480] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0481] In one possible design, the duration of one OFDM symbol is T;

[0482] The duration T1 of the first signal satisfies: T1=M*T*X;

[0483] The duration T2 of the second signal satisfies: T2=M*T*(1-X);

[0484] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0485] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N, and the number P2 of levels included in the second signal is proportional to the value of N.

[0486] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0487] The number P2 of levels included in the second signal satisfies: P2=M*K*N*(1-X);

[0488] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0489] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0490] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0491] In another design:

[0492] The transceiver unit 1120 is configured to receive a synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N*12 subcarriers, where M and N are both positive integers;

[0493] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

[0494] The processing unit 1110 is configured to parse the synchronization signal.

[0495] In one possible design, any level included in the first signal is a first level.

[0496] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0497] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0498] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0499] In one possible design, the duration of one OFDM symbol is T;

[0500] The duration T1 of the first signal satisfies: T1=M*T*X;

[0501] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0502] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0503] In one possible design, the number P1 of levels included in the first signal is proportional to the value of N.

[0504] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X;

[0505] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0506] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0507] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0508] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0509] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0510] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0511] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0512] In one possible design, P2 is equal to 4.

[0513] In yet another design:

[0514] The transceiver unit 1120 is configured to receive a synchronization signal on a first time domain resource and a first frequency domain resource, where the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing (OFDM) symbols, and the first frequency domain resource includes N×12 subcarriers, where M and N are both positive integers.

[0515] In which, the modulation mode of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal, the first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the sum of the duration T1 of the first signal and the duration of the first level in the second signal is a fixed value, and the number P2 of levels included in the second signal is a fixed value.

[0516] The processing unit 1110 is configured to parse the synchronization signal.

[0517] In one possible design, any level included in the first signal is a first level.

[0518] In one possible design, the second signal includes at least one first level and at least one second level, and the number of first levels included in the second signal is equal to the number of second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

[0519] In one possible design, any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

[0520] In one possible design, the duration T2 of the second signal is inversely proportional to the value of N.

[0521] In one possible design, the duration of one OFDM symbol is T;

[0522] The duration T1 of the first signal satisfies: T1=M*T*X-M*T / K*N;

[0523] The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N;

[0524] Wherein, 0<X<1; in the case of M=1, the value of X is associated with the subcarrier spacing.

[0525] In one possible design, the sum of the number P1 of levels included in the first signal and 1 is proportional to the value of N.

[0526] In a possible design, the number P1 of levels included in the first signal satisfies: P1=M*K*N*X-1;

[0527] Wherein, 0<X<1; K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

[0528] In one possible design, when K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

[0529] In a possible design, when M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

[0530] In one possible design, the duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal precedes the first signal, and any level included in the third signal is the second level; wherein:

[0531] The duration T3 of the third signal satisfies: T3=M*T-T1-T2;

[0532] The number P3 of levels included in the third signal satisfies: P3=M*K*N-P1-P2;

[0533] Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer. In one possible design, P2 is equal to 4.

[0534] For other possible implementations of the communication device, reference may be made to the description of the functions of the relevant devices in the method embodiment corresponding to FIG4 above, which will not be described in detail here.

[0535] As shown in Figure 12, the communication device 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are coupled to each other. It will be appreciated that the interface circuit 1220 may be a transceiver or an input / output interface. Optionally, the communication device may further include a memory 1230 for storing instructions executed by the processor 1210, input data required by the processor 1210 to execute instructions, or data generated by the processor 1210 after executing instructions.

[0536] When the communication device is used to implement the method in the above method embodiment, the processor 1210 is used to execute the function of the above processing unit 1110 , and the interface circuit 1220 is used to execute the function of the above transceiver unit 1120 .

[0537] When the communication device is a chip used in a network device, the chip implements the functions of the network device in the above method embodiment. The chip receives information from other devices; or the network device chip sends information to other devices.

[0538] When the above-mentioned communication device is a chip applied to a (passive or semi-passive) tag, the (passive or semi-passive) tag chip realizes the function of the (passive or semi-passive) tag in the above-mentioned method embodiment, and the (passive or semi-passive) tag chip receives information from other devices; or, the (passive or semi-passive) tag chip sends information to other devices.

[0539] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0540] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a (passive or semi-passive) tag. Of course, the processor and storage medium can also exist as discrete components in a network device or a (passive or semi-passive) tag.

[0541] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instruction is loaded and executed on a computer, the process or function described in the embodiment of the present application is executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program or instruction can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, a hard disk, or a tape; it can also be an optical medium, such as a digital versatile disc (DVD); it can also be a semiconductor medium, such as a solid state drive (SSD).

[0542] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0543] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

[0544] An embodiment of the present application also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed, the method executed by the network device or (passive or semi-passive) tag in the above method embodiment is implemented.

[0545] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed, the method executed by the network device or (passive or semi-passive) tag in the above method embodiment is implemented.

[0546] The present application also provides a communication system comprising a network device and a (passive or semi-passive) tag. The network device is configured to execute the method performed by the network device in the aforementioned method embodiment. The (passive or semi-passive) tag is configured to execute the method performed by the (passive or semi-passive) tag in the aforementioned method embodiment.

[0547] The present application also provides a communication method, wherein a network device is used to execute the method executed by the network device in the above method embodiment. A (passive or semi-passive) tag is used to execute the method executed by the (passive or semi-passive) tag in the above method embodiment.

[0548] It should be noted that, for the aforementioned method embodiments, for simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0549] The descriptions of the various embodiments provided in this application can refer to each other. The descriptions of each embodiment have their own focus. For parts not described in detail in a particular embodiment, please refer to the relevant descriptions of other embodiments. For the convenience and brevity of description, for example, the functions and execution steps of the various devices and equipment provided in the embodiments of this application can refer to the relevant descriptions of the method embodiments of this application. The various method embodiments and the various device embodiments can also refer to, be combined with, or quote each other.

[0550] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A communication method, characterized in that: include: determining a synchronization signal; Sending the synchronization signal on a first time domain resource and a first frequency domain resource, the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing OFDM symbols, the first frequency domain resource includes N*12 subcarriers, and both M and N are positive integers; Among them, the modulation method of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal. The first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

2. The method according to claim 1, characterized in that Any level included in the first signal is a first level.

3. The method according to claim 1 or 2, characterized in that: The second signal includes at least one first level and at least one second level, the number of the first levels included in the second signal is equal to the number of the second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

4. The method according to any one of claims 1 to 3, characterized in that: Any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

5. The method according to any one of claims 1 to 4, characterized in that: The duration T2 of the second signal is inversely proportional to the value of N.

6. The method according to any one of claims 1 to 5, characterized in that: The duration of one OFDM symbol is T; The duration T1 of the first signal satisfies: T1 = M*T*X; The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N; Wherein, 0<X<1; when M=1, the value of X is associated with the subcarrier spacing.

7. The method according to any one of claims 1 to 5, characterized in that: The number P1 of levels included in the first signal is proportional to the value of N.

8. The method according to any one of claims 1 to 7, characterized in that: The number P1 of levels included in the first signal satisfies: P1 = M*K*N*X; Wherein, 0<X<1; the K is the number of levels included in one OFDM symbol when the N is equal to 1, and the K is a positive integer.

9. The method according to claim 8, characterized in that When K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

10. The method according to claim 8 or 9, characterized in that: When M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

11. The method according to any one of claims 1 to 10, characterized in that: The duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal is before the first signal, and any level included in the third signal is the second level; wherein: The duration T3 of the third signal satisfies: T3 = M*T - T1 - T2; The number P3 of levels included in the third signal satisfies: P3 = M*K*N - P1 - P2; Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

12. The method according to any one of claims 1 to 11, characterized in that: The P2 is equal to 4.

13. A communication method, characterized in that: include: Receiving a synchronization signal on a first time domain resource and a first frequency domain resource, wherein the duration of the first time domain resource is less than or equal to the duration of M orthogonal frequency division multiplexing OFDM symbols, the first frequency domain resource includes N*12 subcarriers, and both M and N are positive integers; Among them, the modulation method of the synchronization signal is on-off keying (OOK), and the synchronization signal includes a first signal and a second signal. The first signal indicates that the second signal is after the first signal and the second signal is adjacent to the first signal, and the second signal is used for time calibration; the duration T1 of the first signal and the number P2 of levels included in the second signal are both fixed values.

14. The method according to claim 13, characterized in that Any level included in the first signal is a first level.

15. The method according to claim 13 or 14, characterized in that The second signal includes at least one first level and at least one second level, the number of the first levels included in the second signal is equal to the number of the second levels, the second level is higher than the first level, and the duration of the second level is equal to the duration of the first level.

16. The method according to any one of claims 13 to 15, characterized in that: Any adjacent level of the first level included in the second signal is the second level, any adjacent level of the second level included in the second signal is the first level, and the second level is higher than the first level.

17. The method according to any one of claims 13 to 16, characterized in that: The duration T2 of the second signal is inversely proportional to the value of N.

18. The method according to any one of claims 13 to 17, characterized in that: The duration of one OFDM symbol is T; The duration T1 of the first signal satisfies: T1 = M*T*X; The duration T2 of the second signal satisfies: T2=M*T*(1-X) / N; Wherein, 0<X<1; when M=1, the value of X is associated with the subcarrier spacing.

19. The method according to any one of claims 13 to 17, characterized in that: The number P1 of levels included in the first signal is proportional to the value of N.

20. The method according to any one of claims 13 to 19, characterized in that: The number P1 of levels included in the first signal satisfies: P1 = M*K*N*X; Wherein, 0<X<1; the K is the number of levels included in one OFDM symbol when the N is equal to 1, and the K is a positive integer.

21. The method according to claim 20, characterized in that When K is equal to 6, the number P1 of levels included in the first signal is an integer not less than 2, and the number P2 of levels included in the second signal is an integer not less than 2 or an integer not less than 4.

22. The method according to claim 20 or 21, characterized in that When M is equal to 1 and K is equal to 6, X is 1 / 3 or 1 / 2.

23. The method according to any one of claims 13 to 22, characterized in that: The duration of the first time domain resource is equal to the duration of the M OFDM symbols; the synchronization signal further includes a third signal, the third signal is before the first signal, and any level included in the third signal is the second level; wherein: The duration T3 of the third signal satisfies: T3 = M*T - T1 - T2; The number P3 of levels included in the third signal satisfies: P3 = M*K*N - P1 - P2; Wherein, K is the number of levels included in one OFDM symbol when N is equal to 1, and K is a positive integer.

24. The method according to any one of claims 13 to 23, characterized in that: The P2 is equal to 4.

25. A communication device, comprising a unit or module for executing the method according to any one of claims 1 to 12, or comprising a unit or module for executing the method according to any one of claims 13 to 24.

26. A communication device, characterized in that: The device comprises a processor and a transceiver, wherein the processor and the transceiver are used to implement the method according to any one of claims 1 to 12, or to implement the method according to any one of claims 13 to 24.

27. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction. When the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 12 is implemented, or the method according to any one of claims 13 to 24 is implemented.

28. A computer program product, characterized in that The method comprises a computer program code, and when the computer program code is executed on a computer, the method according to any one of claims 1 to 12 is implemented, or the method according to any one of claims 13 to 24 is implemented.

29. A communication system, characterized in that: A communication device comprising a method according to any one of claims 1 to 12, and a communication device comprising a method according to any one of claims 13 to 24.

30. A communication method, characterized in that: The network device is used to execute the method described in any one of claims 1-12, and the tag is used to execute the method described in any one of claims 13-24.

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