Communication method and device

Abstract

The present application provides a communication method and device. A local end receives a first signal; the local end sends a second signal, wherein the second signal comprises a preamble and at least one midamble, and the interval between the preamble and the first midamble is a first time-domain length; and / or the second signal comprises at least two midambles, and the interval between two adjacent midambles is the first time-domain length; the first time-domain length is determined on the basis of a first sampling frequency deviation range, and the first sampling frequency deviation range is determined on the basis of the first signal. In the embodiments, the time-domain length of the interval between a preamble and a midamble or between midambles is defined, and when a peer end receives the second signal, the peer end may perform timing offset correction on the basis of the time-domain length of the interval between a preamble and a midamble or between midambles detected by the peer end and the defined time-domain length (i.e., the first time-domain length) of the interval between a preamble and a midamble or between midambles.

Description

A communication method and apparatus

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410725757.0, filed on June 5, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0004] In recent years, the Internet of Things (IoT) has attracted widespread attention in the field of wireless communication. It is anticipated that more "things" will be interconnected to improve productivity and quality of life. By further reducing the size, complexity, and power consumption of IoT devices, hundreds or even trillions of IoT devices can be deployed for various applications. However, considering the cost of IoT devices, the crystal oscillators used in them have relatively poor accuracy and large sampling time bias. This means that the time perceived by the transmitter and receiver differs each time a sample is taken, leading to discrepancies in the judgment of the sampling results and resulting in decoding errors at the receiver. Summary of the Invention

[0005] This application provides a communication method and apparatus to improve decoding success rate.

[0006] In a first aspect, this application provides a communication method, which can be executed by a communication device, or by other devices including the functions of a communication device, or by a chip system (which can also be replaced by a chip) or other functional module, the chip system or functional module being capable of implementing the functions of the communication device, for example, being disposed in the communication device. The communication device can be a terminal device or a reader. The method includes: receiving a first signal; transmitting a second signal; the second signal including a preamble and at least one intermediate preamble, the preamble and the first intermediate preamble being spaced apart by a first time-domain length; and / or, the second signal including at least two intermediate preambles, adjacent two intermediate preambles being spaced apart by a first time-domain length; the first time-domain length being determined according to a first sampling frequency deviation range, the first sampling frequency deviation range being determined according to the first signal.

[0007] In this embodiment, the time-domain length of the interval between precodes is defined. After receiving the second signal, the receiving end can perform time offset correction based on the time-domain length of the interval between precodes it detects and the agreed-upon time-domain length (i.e., the first time-domain length). It is understood that the shorter the interval between precodes, the better the time offset correction effect, but the higher the overhead. If the maximum sampling frequency deviation SFO (e.g., 10) is used... 5 The time-domain length of the interval between preambles is determined by ppm (i.e., a deviation of 10%). A shorter time-domain length results in denser intermediate preambles and higher overhead. In this embodiment, the time-domain length is determined based on the actual range of the SFO (Signal Optimum Forward Occurrence). This ensures a suitable time-domain length for the interval between preambles, effectively correcting the time offset and guaranteeing correct decoding without making the preambles too dense and increasing overhead. Furthermore, while the upper limit, lower limit, or difference between the upper and lower limits of the actual SFO range are integers, the actual SFO may not be an integer. This makes determining the time-domain length based on the actual SFO more computationally complex than determining it based on the actual SFO range. In other words, determining the time-domain length based on the actual SFO range is computationally simpler.

[0008] In one possible implementation, the first time domain length is determined based on a first sampling frequency deviation range, including: the first time domain length is determined based on a first correlation value of the first sampling frequency deviation range, wherein the first correlation value is the absolute value of the upper limit or the absolute value of the lower limit.

[0009] In one possible implementation, the first time domain length is determined based on a first correlation value of the first sampling frequency deviation range, including: the first time domain length is determined based on the first correlation value and the maximum time deviation value.

[0010] In one possible implementation, the first correlation value, the maximum time offset value, and the first time domain length satisfy the following formula: or Where F is the duration of the smallest time unit, and a is the maximum sampling time offset. This indicates rounding down to the nearest integer.

[0011] In one possible implementation, the method further includes sending a third signal, the third signal being used to indicate the first time domain length.

[0012] In this example, the first time domain length is indicated to the peer, which does not need to calculate the first time domain length, thus reducing the complexity for the peer.

[0013] In one possible implementation, the third signal includes a first preamble, which is associated with the first time-domain length; or, the third signal includes a preamble and indication information, which indicates the first time-domain length, the indication information being located after the preamble, and the indication information being spaced K bits apart from the preamble, where K is an integer greater than or equal to 0.

[0014] In one possible implementation, the first time domain length is determined based on a first sampling frequency deviation range, including: the first time domain length is determined based on a first difference between the upper limit and the lower limit of the first sampling frequency deviation range.

[0015] In one possible implementation, the first time domain length is determined based on the first difference, including: the first time domain length is determined based on the first difference and the maximum time offset deviation value.

[0016] In one possible implementation, the first difference, the maximum time offset value, and the first time domain length satisfy the following formula: or Where F is the duration of the smallest time unit, and a is the maximum sampling time offset. This indicates rounding down to the nearest integer.

[0017] In one possible implementation, the method further includes sending a fourth signal, the fourth signal being used to indicate the first difference or the first time domain length.

[0018] In this example, the first time domain length is indicated to the peer, which does not need to calculate the first time domain length, thus reducing the complexity for the peer.

[0019] In one possible implementation, the second signal is sent after compensating for the sampling frequency deviation based on the upper or lower limit of the first sampling frequency deviation range.

[0020] In this example, after the second communication device compensates for the SFO between the second communication device and the first communication device, the remaining SFO is within the maximum allowable deviation range, for example, the range is [-c, c] or [0, c], where c is the precision.

[0021] In one possible implementation, the preamble and the first intermediate preamble are spaced apart by a first time domain length; and / or, the intermediate preambles are spaced apart by a first time domain length, including: the preamble and the first intermediate preamble are spaced apart by a second time domain length; and / or, the intermediate preambles are spaced apart by a second time domain length; wherein the second time domain length is: the third time domain length among a plurality of pre-stored third time domain lengths that is less than or equal to the first time domain length and has the smallest difference from the first time domain length.

[0022] In this example, the second time domain length does not exceed the first time domain length because the first time domain length determined based on the first SFO range is more accurate than the pre-saved third time domain length. The first time domain length can be understood as the maximum tolerance time for accumulated deviation. If the second time domain length exceeds the first time domain length, it will lead to more accumulated deviation and reduce the decoding accuracy.

[0023] In one possible implementation, the method further includes sending a fifth signal, the fifth signal being used to indicate the second time domain length.

[0024] In this example, the second time domain length is indicated to the peer, so the peer does not need to calculate the first time domain length, which reduces the complexity for the peer.

[0025] In one possible implementation, where the second signal includes a preamble and two intermediate preambles, with a first time-domain length between the preamble and the first intermediate preamble, the first intermediate preamble and the second intermediate preamble are spaced N times the first time-domain length, where N is a positive integer greater than or equal to 1, and N is determined based on the accuracy of the supported sampling frequency deviation range.

[0026] In this example, the transmitter assumes that the receiver will perform time offset correction (i.e., compensation) after receiving the first intermediate preamble, and will receive the content following the first intermediate preamble based on the corrected time offset. After compensation, the remaining offset is small, so the transmitter can place the next intermediate preamble after a longer time interval; that is, the time domain length between the second and first intermediate preambles can be greater than the first time domain length.

[0027] The time-domain length between the second and first intermediate preambles can be determined based on the actual range of the SFO (Signal-Focused Forward Oscillator). This ensures a suitable time-domain interval between preambles, effectively correcting time offsets and guaranteeing correct decoding without excessive preamble density that would increase overhead. However, while the upper or lower limit, or the difference between the upper and lower limits of the actual SFO range are integers, the actual SFO may not be an integer. This makes determining the time-domain length based on the actual SFO more computationally complex than determining it based on the actual SFO range. In other words, determining the time-domain length based on the actual SFO range is computationally simpler. Furthermore, the difference between the upper and lower limits of the SFO is usually fixed; using the difference to determine the time-domain length further simplifies the computation compared to using either the upper or lower limit.

[0028] Secondly, this application provides a communication method that can be executed by a communication device, or by other devices including the functions of a communication device, or by a chip system (which can also be replaced by a chip) or other functional module capable of implementing the functions of the communication device, such as being disposed within the communication device. The communication device can be a terminal device or a reader. The method includes: transmitting or receiving a sixth signal, the sixth signal including a preamble and at least two intermediate preambles, the preamble and the first intermediate preamble being spaced apart by a fourth time-domain length; the first intermediate preamble and the second intermediate preamble being spaced apart by a fifth time-domain length, the fifth time-domain length being N times the fourth time-domain length, where N is a positive integer greater than or equal to 1, and N is determined based on the difference between the upper and lower limits of a supported sampling frequency deviation range.

[0029] In this embodiment, the transmitter assumes that the receiver will perform time offset correction (i.e., compensation) after receiving the first intermediate preamble, and receive the content following the first intermediate preamble based on the corrected time offset. After compensation, the remaining offset is small, so the transmitter can place the next intermediate preamble after a longer time interval. That is, the fifth time-domain length between the second and first intermediate preambles can be greater than the fourth time-domain length. The fifth time-domain length can be determined based on the actual range of the SFO, making the time-domain length between preambles appropriate, which can both effectively correct the time offset and ensure correct decoding, without making the preambles too dense and increasing overhead. However, the upper limit, lower limit, or difference between the upper and lower limits of the actual SFO range are all integers, but the actual SFO may not be an integer. This makes determining the fifth time-domain length based on the actual SFO more computationally complex than determining it based on the actual range of the SFO. In other words, determining the fifth time-domain length based on the actual range of the SFO is computationally simpler. Furthermore, the difference between the upper and lower limits of SFO is usually fixed. Compared to using the upper or lower limit to determine the length of the fifth time domain, using the difference to determine the length of the fifth time domain will further simplify the calculation.

[0030] In one possible implementation, the method further includes: sending or receiving a seventh signal, the seventh signal comprising a preamble and at least one intermediate preamble, the preamble and the first intermediate preamble being spaced apart by the fifth time-domain length; the time interval between the seventh signal and the sixth signal being less than or equal to a first time duration. For example, the first time duration is one day or one week, etc.

[0031] In this example, after determining the length of the fifth time domain, the fifth time domain length is still used for a shorter time (i.e., the first time duration), which can reduce the amount of computation. In addition, the fifth time domain length is longer than the fourth time domain length, and the placement of intermediate precodes is more sparse, resulting in less overhead.

[0032] In one possible implementation, the fourth time-domain length is determined based on the maximum sampling frequency deviation value.

[0033] In one possible implementation, N is determined based on the difference between the upper and lower limits of the supported SFO range.

[0034] Thirdly, this application provides a communication method that can be executed by a communication device, or by other devices including the functions of a communication device, or by a chip system (which can also be replaced by a chip) or other functional module capable of implementing the functions of the communication device, such as being disposed within the communication device. The communication device can be a terminal device or a reader. The method includes: transmitting or receiving an eighth signal, the eighth signal including an intermediate preamble and / or a post-preamble; transmitting or receiving a ninth signal, the ninth signal not including a preamble, the duration of the interval between the ninth signal and the eighth signal being less than or equal to a second duration.

[0035] In this embodiment, after receiving the eighth signal, the second communication device can perform time offset correction based on the preamble (which may be the last preamble) included in the eighth signal. Within a short period of time after the eighth signal (i.e., within the second duration), synchronization can be performed without a preamble, thus reducing signal overhead by omitting the transmission of the preamble.

[0036] In one possible implementation, the time interval between the ninth signal and the eighth signal is less than or equal to the second time interval, including: the time interval between the ninth signal and the last preamble in the eighth signal is less than or equal to the second time interval.

[0037] In one possible implementation, the ninth signal includes at least one intermediate preamble; the duration of the interval between the first intermediate preamble and the eighth signal is less than or equal to a second duration and / or greater than or equal to a third duration, wherein the third duration is the second duration minus a minimum time unit.

[0038] Fourthly, a communication device is provided, which can be a terminal device as described in the preceding aspects. The communication device possesses the functions of the aforementioned terminal device. The communication device is, for example, a functional module within the terminal device, such as a baseband device or a chip system. Alternatively, the communication device can be a reader as described in the preceding aspects. The communication device possesses the functions of the aforementioned reader. The communication device is, for example, a functional module within the reader, such as a baseband device or a chip system.

[0039] In one optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also called a processing module) and a transceiver unit (sometimes also called a transceiver module). The transceiver unit is capable of transmitting and receiving functions. When the transceiver unit performs the transmitting function, it can be called a transmitting unit (sometimes also called a transmitting module), and when the transceiver unit performs the receiving function, it can be called a receiving unit (sometimes also called a receiving module). The transmitting unit and the receiving unit can be the same functional module, which is called the transceiver unit and can perform both transmitting and receiving functions; or, the transmitting unit and the receiving unit can be different functional modules, and the transceiver unit is a collective term for these functional modules.

[0040] In one possible implementation, the communication device further includes a storage unit (sometimes also called a storage module), and the processing unit is configured to couple with the storage unit and execute programs or instructions in the storage unit to enable the communication device to perform the functions of the terminal device described in the foregoing aspects, or to perform the functions of the reader described in the foregoing aspects.

[0041] Fifthly, a communication device is provided, including an interface circuit and a processor, and optionally, a memory. The memory stores a computer program. The processor is coupled to the memory and the interface circuit. When the processor reads the computer program or instructions, it causes the communication device to execute the methods executed by the terminal device or the methods executed by the reader in the aforementioned aspects. For example, the interface circuit is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. The processor, through logic circuits or executable code instructions, implements the methods executed by the terminal device or the methods executed by the reader in the aforementioned aspects.

[0042] In one possible implementation, the communication device is a chip or chip system.

[0043] In a sixth aspect, a communication device is provided, including a processor, and optionally, a memory; the processor and the memory are coupled; the memory is used to store computer programs or instructions; the processor is used to execute part or all of the computer programs or instructions in the memory, and when the part or all of the computer programs or instructions are executed, to implement the functions of a terminal device in the above aspects, or to implement the functions of a reader in the above aspects.

[0044] In one possible implementation, the apparatus may further include a transceiver for transmitting signals processed by the processor or receiving signals input to the processor. The transceiver may perform transmitting or receiving actions performed by the terminal device or the reader in various aspects.

[0045] In one possible implementation, the processing unit in the fourth aspect can be implemented by the processor, the storage unit in the fourth aspect can be implemented by the memory, and the transceiver unit in the fourth aspect can be implemented by the transceiver.

[0046] In one possible implementation, the communication device is a chip or chip system.

[0047] In a seventh aspect, a computer-readable storage medium is provided for storing a computer program or instructions that, when executed, cause the methods of the preceding aspects to be implemented.

[0048] Eighthly, a computer program product containing instructions is provided that, when run on a computer, enables the methods in the above-described aspects to be implemented. Attached Figure Description

[0049] Figures 1a and 1b are schematic diagrams of the communication system architecture provided in the embodiments of this application;

[0050] Figure 1c is a schematic diagram of the structure of an AIoT device provided in an embodiment of this application;

[0051] Figures 2a and 2b are schematic diagrams of sampling deviations provided in the embodiments of this application;

[0052] Figure 3 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0053] Figures 4a, 4b, 4c and 4d are schematic diagrams of signal structures provided in the embodiments of this application;

[0054] Figures 5a and 5b are schematic diagrams of the detection signals provided in the embodiments of this application;

[0055] Figure 6 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0056] Figure 7 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0057] Figure 8 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0058] Figures 9a and 9b are schematic diagrams of signal interval duration provided in the embodiments of this application;

[0059] Figure 10 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0060] Figure 11 is a structural diagram of a communication device provided in this application;

[0061] Figure 12 is a structural diagram of a communication device provided in this application. Detailed Implementation

[0062] The technical solution of this application can be applied to terrestrial networks (TN) and non-terrestrial networks (NTN), such as satellite networks. The technical solution of this application can be applied to various wireless communication systems, including but not limited to fourth-generation (4G) systems (also known as Long Term Evolution, LTE), fifth-generation (5G) systems (also known as New Radio, NR), or future communication systems or other similar communication systems, without specific limitations. The technical solution of this application can also be applied to the Internet of Things (IoT), passive IoT (P-IoT; or ambient IoT, A-IoT), semi-passive IoT, semi-active IoT, active IoT, narrowband Internet of Things (NB-IoT), machine-to-machine (M2M) networks, machine-type communication (MTC), or other networks. Furthermore, the technical solution of this application can be applied to device-to-device (D2D) scenarios, such as NR-D2D scenarios, or to V2X scenarios, such as NR-V2X scenarios. The technical solution of this application can also be applied to fields such as intelligent driving, assisted driving, intelligent connected vehicles, or factory manufacturing scenarios.

[0063] Figures 1a and 1b are schematic diagrams of the communication system structure applicable to this application. In Figure 1a, the base station communicates directly with the terminal device. In Figure 1b, the base station communicates with the terminal device through an intermediate node.

[0064] For the sake of consistency, the base station in Figure 1a and the intermediate node in Figure 1b can both be referred to as a Reader, while the terminal device can be referred to as a Device. Sending messages from a Reader to a Device can be called R2D communication, and sending messages from a Device to a Reader can be called D2R communication. It should be understood that R2D and D2R are just names of communication methods, and these names can be replaced with other names.

[0065] Terminal devices can be terminal devices in the Internet of Things (IoT) technology, including but not limited to passive terminal devices, semi-passive terminal devices, semi-active terminal devices, active terminal devices, low-power terminal devices, zero-power terminal devices, passive terminal devices, active terminal devices, tags (e.g., passive tags, active tags, semi-active tags, semi-passive tags), sensors, electricity meters, water meters, metering devices, billing devices on bicycles (e.g., shared bicycles), bicycle locks, and other IoT devices. Tags include at least two types: one type of tag has an output power consumption of approximately 1 μW, has energy storage devices, and lacks downlink and uplink signal amplification capabilities, only capable of backscattering (i.e., reflecting) information transmission on an externally provided carrier wave. The other type of tag has a peak power of no more than several hundred μW, possesses energy storage capabilities, and can amplify downlink and / or uplink signals. This tag can generate signals internally or reflect signals through an external carrier wave.

[0066] Intermediate nodes can be devices with wireless transceiver capabilities, deployed on land (indoors or outdoors, handheld or vehicle-mounted), on water (such as ships), or in the air (e.g., on airplanes, balloons, and satellites). Examples include mobile phones, tablets, computers with wireless transceiver capabilities, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, and wireless terminals in smart homes.

[0067] Figure 1c shows a schematic diagram of an AIoT device. The AIoT device includes one antenna or two antennas. When there are two antennas, one antenna is used to receive signals or carrier waves, and the other antenna is used to reflect the information to be transmitted onto the carrier wave or generate an uplink signal to send out.

[0068] When the cost of terminal equipment is very low, the crystal oscillator used is inaccurate, which leads to a difference in the time perceived by the transmitting end and the receiving end, resulting in a deviation in the judgment of the sampling results.

[0069] As shown in Figure 2a, short arrows indicate that the data at that sampling point is 0, and long arrows indicate that the data at that sampling point is 1. The arrows represent the data sent by the transmitting end. The data 0, 1, 0, 1, 0 represents the data sent by the transmitting end, and a single value represents the average sampling value of the transmitting end within a minimum time unit. The data 0, 0.8, 0.2, 0.4, 0.6, 0, 0.8 represents the data received by the receiving end, and a single value represents the average sampling value of the receiving end within a minimum time unit. The number of samples corresponding to a minimum time unit is fixed. Since the clock at the receiving end runs slower than the clock at the transmitting end, the sampling frequency at the receiving end is lower than that at the transmitting end. Therefore, the minimum time unit detected by the receiving end is shorter than the minimum time unit used by the transmitting end, and the data received by the receiving end is inaccurate.

[0070] As shown in Figure 2b, short arrows indicate that the data at that sampling point is 0, and long arrows indicate that the data at that sampling point is 1. The arrows represent the data sent by the transmitting end. The data 0, 1, 0, 1, 0 represents the data sent by the transmitting end, with each value representing the average sampling value within a minimum time unit. The data 0.1, 0.8, 0.3, 0.5, 0.8 represents the data received by the receiving end, with each value representing the average sampling value within a minimum time unit. The number of samples corresponding to a minimum time unit is fixed. Since the clock at the receiving end runs faster than the clock at the transmitting end, the sampling frequency at the receiving end is higher than that at the transmitting end. Therefore, the minimum time unit detected by the receiving end is longer than the minimum time unit used by the transmitting end, resulting in inaccurate data received by the receiving end.

[0071] Based on this, embodiments of this application propose time offset correction using an intermediate preamble.

[0072] The following explanations of some terms or concepts used in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0073] 1) Signals, also known as information or messages, are carried on a carrier wave.

[0074] The signals in this application are transmitted in a high-low level manner, where a high level can be represented by "1" and a low level can be represented by "0".

[0075] Unless otherwise specified, a signal includes: a preamble, one or more data portions (for carrying data to be transmitted), one or more midambles, and a postamble. The preamble precedes all midambles, and the data portion is between the preamble and the first midamble; the postamble follows all midambles, and the data portion is between the last midamble and the postamble; if there are multiple midambles, the data portion is also between each midamble. In several embodiments of this application, the preamble is omitted from some signals to reduce preamble transmission overhead; the midamble is omitted from some signals to reduce midamble transmission overhead; and the postamble may be omitted from some signals to reduce postamble transmission overhead.

[0076] The preamble, intermezzo, and postamble are each a regular sequence of bits, known to both the sender and receiver. Below are some examples of preambles, where high represents a high voltage level and low represents a low voltage level:

[0077] (1): High, low, high, low alternating; (2): High, low, high, high, low, low, repeating this pattern multiple times; (3): High, high, low, low, high, low, repeating this pattern multiple times; (4): High, low, low, repeating this pattern multiple times; (5): High, high, low, repeating this pattern multiple times.

[0078] The intermediate and post-preamble codes can also use a similar structure to the preamble, with high and low levels interleaved to obtain the sequence. The three preamble codes may use a fixed sequence or one of several sequences.

[0079] The preamble indicates the start of data transmission. After the receiver receives the preamble, it can be assumed that the receiver and transmitter are approximately synchronized, meaning the following content is the data portion. After the preamble, as sampling time offset begins to accumulate, an intermediate preamble can be used for time offset correction. The postamble indicates the end of a transmission; alternatively, the end position of a transmission can be indicated by control information, eliminating the need for a postamble; or, if no level signal is received for an extended period, the transmission is considered complete.

[0080] 2) Maximum sampling time offset and sampling frequency:

[0081] Sampling time bias is caused by sampling frequency offset (SFO). Unless otherwise specified, sampling time bias and SFO can be considered to have the same meaning.

[0082] For example, the bias is 10 during maximum sampling. 5 At ppm, the sampling frequency can deviate by a maximum of 10% (i.e., 10). 5 / 10 6 ppm refers to parts per million, and its unit is 10. 6 At a sampling frequency of 3MHz (i.e., 3*10 samples per second). 6 The equipment, which is designed for production (with the goal of producing multiple samples), has an actual sampling frequency between 2.7MHz and 3.3MHz.

[0083] For example, when the maximum sampling bias is 100ppm, the sampling frequency can deviate by up to one ten-thousandth. Equipment manufactured with a target sampling frequency of 100MHz actually has a sampling frequency between 99.99MHz and 100.01MHz.

[0084] 3) Time offset correction, also known as sampling frequency correction:

[0085] The transmitting and receiving ends know the number of samples corresponding to the smallest time unit, which can be a chip or a symbol. A chip is a unit of information after spread spectrum modulation and can represent a time length.

[0086] For example, if a minimum time unit corresponds to p samples, and the transmitter sends a signal with a length of 10 minimum time units, then if there is no sampling time offset between the receiver and the transmitter, the receiver will receive all the signals after sampling 10*p times.

[0087] In one example, due to sampling time skew, the receiver receives all the signals after sampling 10 * 1.1p times. Therefore, the sampling time skew at the receiver is (1.1p - 10p) / 10p = 10%. The receiver's clock runs faster than the transmitter's clock, and its sampling frequency is higher. Subsequently, when the receiver sends a signal to the transmitter, it sends the signal by sampling 1.1p times in a minimum time unit, and the transmitter can decode it correctly. Alternatively, when the receiver receives a signal from the transmitter, it receives the signal by sampling 1.1p times in a minimum time unit, and the receiver can decode it correctly. Here, "the receiver sends or receives signals by sampling 1.1p times in a minimum time unit" can be understood as time skew correction.

[0088] In another example, due to sampling time skew, the receiver receives all the signals after sampling 10 * 0.95p times. Therefore, the sampling time skew at the receiver is (0.95p - 10p) / 10p = -5%. The receiver's clock runs slower than the transmitter's clock, and the receiver's sampling frequency is lower than the transmitter's sampling frequency. Subsequently, when the receiver sends a signal to the transmitter, it sends the signal according to a minimum time unit sampling of 0.95p times, and the transmitter can decode it correctly. Alternatively, when the receiver receives a signal from the transmitter, it receives the signal according to a minimum time unit sampling of 0.95p times, and the receiver can decode it correctly. Here, "the receiver sends or receives signals according to a minimum time unit sampling of 0.95p times" can be understood as time skew correction.

[0089] 4) The methods provided in the various embodiments of this application can be applied to the network architecture shown in Figures 1a and 1b or other network architectures. For example, in the various embodiments of this application, the first communication device is the terminal device in Figure 1a, and the second communication device is the base station (also called a reader) in Figure 1a; or, the second communication device is the terminal device in Figure 1a, and the first communication device is the base station in Figure 1a. For example, in the various embodiments of this application, the first communication device is the terminal device in Figure 1b, and the second communication device is the intermediate node (also called a reader) in Figure 1b; or, the second communication device is the terminal device in Figure 1b, and the first communication device is the intermediate node in Figure 1b.

[0090] This application describes several embodiments, each of which can stand alone as an embodiment, or two or more embodiments can be combined as an embodiment without logical errors.

[0091] To better illustrate the embodiments of this application, the methods provided by the embodiments of this application will be described in conjunction with the accompanying drawings. Unless otherwise specified below, the steps represented by dashed lines in the accompanying drawings corresponding to the various embodiments of this application are optional steps. The methods provided by the embodiments of this application can be executed by a communication device, or by other devices including the functions of a communication device, or by a chip system (which can also be replaced by a chip) or other functional modules. The chip system or functional module can implement the functions of the communication device, and the chip system or functional module is, for example, disposed in the communication device. When the executing entity is the aforementioned chip system or other functional module, receiving / transmitting can be understood as input / output. For example, the aforementioned chip system or other functional module communicates with other functional modules or components of the communication device. Furthermore, the processing performed by a single executing entity can also be divided into multiple executing entities, which can be logically and / or physically separated.

[0092] Example 1:

[0093] Figure 3 is a flowchart illustrating a communication method provided in an embodiment of this application, including the following steps:

[0094] Step 301: The first communication device sends a first signal, and correspondingly, the second communication device receives the first signal.

[0095] The first signal can be a synchronization signal (which does not carry data) or a signal that carries data. There are no restrictions on the form of the first signal, as long as the second communication device can determine the sampling frequency deviation range SFO based on the first signal.

[0096] Step 302: The second communication device sends a second signal, and correspondingly, the first communication device receives the second signal.

[0097] Wherein, the second signal includes a preamble and at least one intermediate preamble, wherein the preamble and the first intermediate preamble are spaced apart by a first time domain length; and / or, the second signal includes at least two intermediate preambles, wherein adjacent two intermediate preambles are spaced apart by a first time domain length.

[0098] The following describes several possible structures for the second signal:

[0099] In one example, the second signal includes a preamble and at least one intermediate preamble, as shown in Figure 4a, with a first time-domain length between the preamble and the first intermediate preamble. If the second signal includes multiple intermediate preambles, the time interval between two adjacent intermediate preambles is not limited.

[0100] In another example, the second signal includes at least two intermediate preambles, with a first time-domain length between adjacent intermediate preambles. The second signal may or may not include a preamble; if the second signal includes a preamble, the duration of the interval between the preamble and the first intermediate preamble is not limited.

[0101] In another example, the second signal includes a preamble and at least two intermediate preambles, as shown in Figure 4b. The preamble and the first intermediate preamble are separated by a first time-domain length, and the first and second intermediate preambles are also separated by a first time-domain length. Further optionally, any two adjacent intermediate preambles are separated by the first time-domain length.

[0102] In another example, the second signal includes a preamble and at least two intermediate preambles. The preamble and the first intermediate preamble are spaced apart by a first time-domain length, and the first intermediate preamble and the second intermediate preamble are spaced apart by a multiple of the first time-domain length, where N is a positive integer greater than or equal to 1. N is determined based on the difference between the upper and lower limits of the sampling frequency deviation range supported by the first and / or second communication devices. As shown in Figure 4c, the preamble and the first intermediate preamble are spaced apart by M chips (i.e., the first time-domain length), and the first intermediate preamble and the second intermediate preamble are spaced apart by M*N chips (i.e., the second time-domain length).

[0103] Based on the various structures of the second signal described above, the second signal may further optionally include a postcode, which is located at the end of the second signal, while the precode and intermediate precode are located before the postcode.

[0104] It is understandable that the data to be transmitted is between the preamble and the intermediate preamble, between the intermediate preambles, and between the last intermediate preamble and the postamble.

[0105] The first time domain length is determined based on the first sampling frequency deviation range, and the first sampling frequency deviation range is determined based on the first signal.

[0106] Optionally, in step 303: after receiving the second signal (i.e., step 302), the first communication device can perform time offset correction / sampling frequency correction based on the first time domain length.

[0107] For example, based on the first time domain length, the number of samples between the preamble and the first intermediate preamble in the second signal, and / or, the first communication device performs time offset correction / sampling frequency correction based on the number of samples between the first preamble and the second intermediate preamble in the second signal. After time offset correction / sampling frequency correction, data after the first intermediate preamble in the second signal can be decoded, or signals can be sent to or received from the second communication device.

[0108] For example, if the first time domain length is 10 chips and one chip corresponds to p samples, and if there is no sampling time offset or SFO=0 between the first communication device and the second communication device, then the first communication device samples a total of 10p times between the preamble and the first intermediate preamble in the second signal.

[0109] In one example, due to sampling time skew or SFO, the first communication device samples the preamble and the first intermediate preamble in the second signal a total of 10 * 1.05 * p times. Therefore, the sampling time skew or SFO is (10 * 1.05 * p - 10 p) / 10 p = 5%. The clock of the first communication device runs faster than the clock of the second communication device, and the sampling frequency of the first communication device is higher than that of the second communication device. The first communication device can determine a new sampling frequency, which is 105% of the original sampling frequency. The first communication device can use the new sampling frequency to sample and decode the data after the first intermediate preamble in the second signal, thereby improving the decoding accuracy of the data after the first intermediate preamble.

[0110] In addition, the first communication device can also send signals to the second communication device using a new sampling frequency (i.e., one chip corresponds to 1.05p sampling time).

[0111] In one example, due to sampling time skew or SFO, the first communication device samples the preamble and the first intermediate preamble in the second signal a total of 10 * 0.95 * p times. Therefore, the sampling time skew or SFO is (10 * 0.95 - 10p) / 10p = -5%. The clock of the first communication device runs slower than the clock of the second communication device, and the sampling frequency of the first communication device is lower than that of the second communication device. The first communication device can determine a new sampling frequency, which is 95% of the original sampling frequency. Using this new sampling frequency to decode the data after the first intermediate preamble in the second signal improves the accuracy of the data after the first intermediate preamble.

[0112] In addition, the first communication device can also send signals to the second communication device using a new sampling frequency (i.e., one chip corresponds to 0.95p sampling time).

[0113] In this embodiment, the time-domain length of the interval between precodes is defined. After receiving the second signal, the receiving end can perform time offset correction based on the time-domain length of the interval between precodes it detects and the agreed-upon time-domain length. It is understood that the shorter the time interval between precodes, the better the time offset correction effect, but the overhead will also be greater.

[0114] If we follow the largest SFO (e.g., 10) 5ppm (i.e., a deviation of 10%) determines the time-domain length of the interval between preambles. A shorter time-domain length results in denser intermediate preambles and higher overhead. For example, if the maximum time offset is 0.3 µs and the minimum time unit (e.g., one chip) is 2 µs, then one minimum time unit introduces a maximum sampling time offset of 0.2 µs. If one preamble is placed in 5 minimum time units, then the time-domain length of the interval between preambles is 5 minimum time units, for example, 5 chips.

[0115] In this embodiment, the first time-domain length involved in the second signal in step 302 is determined based on the first sampling frequency deviation range, which is determined based on the first signal. That is, the first time-domain length is determined based on the actual range of the SFO. Determining the time-domain length based on the actual range of the SFO ensures that the time-domain length of the interval between preambles is appropriate, effectively correcting time offsets and ensuring correct decoding, while preventing the preambles from being too dense and increasing overhead.

[0116] In addition, the upper limit, lower limit, or difference between the upper and lower limits of the actual SFO range are all integers, but the actual SFO may not be an integer. This makes it more complicated to determine the time domain length based on the actual SFO than based on the range of the actual SFO. In other words, it is simpler to determine the time domain length based on the range of the actual SFO.

[0117] Optionally, after step 301 and before step 302, the second communication device may determine a first SFO range based on the first signal, and then determine a first time domain length based on the first SFO range. The following describes an example of the second communication device determining the first SFO range based on the first signal:

[0118] The second communication device can determine the range of the SFO, i.e. the first SFO range, based on the first signal.

[0119] For example, the first communication device can determine the first signal based on Manchester encoding or pulse interval encoding (PIE) and send it to the second communication device. The second communication device can determine the SFO based on the falling edge position (i.e., the transition position) of the first signal.

[0120] Figure 5a shows a schematic diagram of Manchester encoding. Manchester will change at the middle position of each bit. For example, a change from high level to low level represents "1", and a change from low level to high level represents "0". For example, a change from high level to low level represents "0", and a change from low level to high level represents "1".

[0121] For example, the first communication device transmits signals with each chip occupying p sampling durations. In the Manchester code mode, there will be a rising edge or falling edge in the middle of each chip. The second communication device can identify the potential range of the first SFO based on the interval between the rising edge or falling edge between two consecutive chips. For instance, if the second communication device collects 1.05p sampling points from the middle of the first chip to the middle of the second chip, then the sampling time offset between the first and second communication devices is (1.05pp) / p = 5%. After determining the sampling time offset, the second communication device can generate the duration of a single chip in the transmitted signal based on 1.05p, thereby reducing the sampling time deviation with the first communication device.

[0122] Figure 5b illustrates a schematic of PIE. When the duration of the high and low levels is the same, the position of the high-low level transition (i.e., the position of the falling edge) represents "0". When the duration of the high level is three times that of the low level, the position of the high-low level transition (i.e., the position of the falling edge) represents "1".

[0123] For example, the first communication device transmits signals with each chip occupying p sampling durations. In PIE code mode, both data 0 and data 1 have a low-level condition, meaning a low level is followed by a rising edge after a falling edge. The second communication device receives a falling edge and the interval between the next rising edge is 0.9p sampling points, thus the calculated sampling time offset is (0.9pp) / p = -10%. After determining the sampling time offset, the second communication device can generate the duration of a single chip in the transmitted signal based on 0.9p, thereby reducing the sampling time deviation with the first communication device.

[0124] The upper and lower limits of the first SFO range may or may not be included in the range. For example, the first SFO range is [s1, s2] or (s1, s2] or (s1, s2), where s1 <s2。

[0125] The second communication device supports one or more SFO ranges with varying precision, where precision refers to the difference between the upper and lower limits of the SFO range. One precision corresponds to a set of SFO ranges, and a set of SFO ranges includes multiple consecutive SFO ranges. For example, a precision of 10... 4 A set of SFO ranges includes: [-10 5 ppm, -9*10 4 ppm), ..., [-10 4 ppm, 0), [0, 10 4ppm], (10 4 ppm, 2*10 4 ppm],…,(9*10 4 ppm, 10 5 [ppm] These SFO ranges. For example, an accuracy of 5*10 3 A set of SFO ranges includes: [-10 5 ppm, -9.5*10 4 ppm), [-9.5 5 ppm, -9*10 4 ppm)...,[0,5*10 3 ppm], (5*10 3 ppm, 10 4 ppm],…,(9.5*10 4 ppm, 10 5 [ppm] These SFO ranges. For example, the first SFO range is (10 ppm). 4 ppm, 2*10 4 [ppm] or (9.5*10] 4 ppm, 10 5 [ppm]. The sign of the SFO range indicates whether the sampling frequency at this end is higher or lower than that at the other end.

[0126] The second communication device determines the first time domain length based on the first SFO range in the following ways, including but not limited to: Method 1: The first time domain length is determined according to a first correlation value of the first SFO range, where the first correlation value is the upper limit of the first SFO, or the absolute value of the upper limit, or the lower limit, or the absolute value of the lower limit. Method 2: The first time domain length is determined according to a first difference between the upper limit and the lower limit of the first SFO range.

[0127] The following is an introduction to method 1:

[0128] The second communication device or third-party equipment stores the correlation relationship between the SFO range's associated values ​​(upper limit, or absolute value of the upper limit, or lower limit, or absolute value of the lower limit) and the time domain length. This correlation relationship can be represented by a table, a formula, or other methods. After determining the first SFO range, the second communication device can determine the time domain length associated with the first associated value, i.e., the first time domain length, based on the first associated value of the first SFO. The second communication device can calculate the first time domain length based on the first associated value using the following formula, or it can find the first time domain length by looking up a table based on the first associated value.

[0129] In one possible example, the first correlation value of the first time domain length and the first SFO range satisfies the following formula 1:

[0130] in:

[0131] W is a constant, for example, W is 10. 6 .

[0132] K represents the percentage of the maximum tolerable time offset within a single smallest time unit, and K can take any value between 0 and 1. In one alternative example, K is determined based on the maximum time offset value 'a', for example,

[0133] F represents the duration of the smallest time unit. For example, the smallest time unit can be a chip or a symbol. For instance, a chip can be 66.67µs, 71.4µs, 35.7µs, etc. For example, at 15kHz, a symbol length is 66.67µs, and at 30kHz, a symbol length is 33.33µs. Alternatively, a chip can be a symbol or a fraction of a symbol; for example, at 15kHz, a symbol length is 66.67µs, while a chip can be 33.33µs, 16.67µs, etc. Optionally, the length of the smallest time unit is related to the maximum SFO value (e.g., 5%, 10%). For example, the maximum SFO value is 10... 5 ppm, which means a deviation of 10%.

[0134] when It can be seen that the length of the first time domain can be determined based on the first correlation value and the maximum time offset value a of the first SFO range.

[0135] In one possible example, the first time domain length, the first correlation value of the first SFO range, and the maximum time offset value a satisfy the following formula 2 (i.e., ... Substituting into Formula 1, we get Formula 2:

[0136] In one possible example, the length of the first time domain is M minimum time units, i.e. Then, the first correlation value of M and the first SFO range satisfies the following formula 3:

[0137] when At that time, M, the first correlation value of the first SFO range, and the maximum time offset value satisfy the following formula 4 (that is, ... Substituting into formula 3, we get formula 4):

[0138] When W=10 6 With the smallest time unit being one chip, and one chip being 66.67µs, based on Equation 4, we can obtain the following Equation 5:

[0139] It is important to note that the first correlation value in formulas 1-5 above can be a positive number or 0, but not a negative number. For example, the range of the first SFO is (3*10). 4 ppm, 4*10 4 [ppm], the first correlation value can be the lower limit value of 3*10 4 It can also be the upper limit of 4*10. 4 For example, the first SFO range is (-4*10). 4 ppm, -3*10 4 [ppm], the first associated value can be the absolute value of the upper limit, 3*10. 4 It can also be the absolute value of the lower limit, 4*10. 4 The first associated value is not the upper limit value - 3 * 10. 4 It is not the lower limit value -4*10 4 .

[0140] In one possible example, the first correlation value is the larger of the absolute values ​​of the upper and lower limits. A larger SFO (Signal Optimal Forecast Value) results in denser precode placement and shorter time-domain intervals between precodes. This is also evident from the formula above. A larger first correlation value leads to a shorter first time-domain length, resulting in better time offset correction. Therefore, using a larger SFO value within the range to determine the time-domain length can correct time offsets caused by larger SFOs, as well as those caused by smaller SFOs. Conversely, using a smaller SFO value results in a longer time-domain length, which is less effective at correcting time offsets caused by larger SFOs, leading to a decrease in decoding accuracy. While this can reduce overhead, accurate decoding is more important than reducing overhead. Therefore, by setting the first correlation value to the larger of the absolute values ​​of the upper and lower limits, time offset can be effectively corrected, ensuring accurate decoding without excessive overhead. Compared to using the largest SFO to determine the time-domain length, this approach ensures both accurate decoding and reduced overhead.

[0141] In one possible implementation, the above formulas 1-5 can be modified in the following ways:

[0142] For example, the content on the right side of the "=" sign in formulas 1-5 above can be treated as a whole and rounded down. This can be either rounding up or down, ensuring that the smallest time unit whose first time domain length is an integer multiple. For example, formula 5 can be transformed into: in, This indicates rounding down. Other formulas undergo similar transformations, which will not be elaborated further.

[0143] For example, the first SFO range is (10 4 ppm, 2*10 4 [ppm], the upper limit value (i.e., the first associated value) is 2*10 4 Substituting into formula 5, we get: When a = 33.33us, Approximately 25, M=25, meaning the first time domain length is 25 chips.

[0144] For example, the first SFO range is (-4*10) 4 ppm, -3*10 4 [ppm], the absolute value of the lower limit (i.e., the first correlation value) 4*10 4 Substituting into formula 5, we get: When a = 33.33us, It is approximately 12.5, M=12, meaning the first time domain length is 12 chips.

[0145] For example, the first SFO range is [5*10 4 ppm, 5.5*10 4 [ppm], with the upper limit (i.e., the first associated value) 5.5 * 10 4 Substituting into formula 5, we get: When a = 33.33us, It is approximately 9.01, M=9, meaning the first time domain length is 9 chips.

[0146] For example, consider the content on the right side of the "=" sign in formulas 1-5 above as a whole, round it down, and then multiply it by a coefficient. Rounding can be done by rounding up or rounding down.

[0147] For example, consider the content on the right side of the "=" sign in formulas 1-5 above as a whole, multiply it by a coefficient, and then round down. Rounding can be either up or down.

[0148] For example, consider the content on the right side of the "=" sign in formulas 1-5 above as a whole multiplied by a coefficient.

[0149] For example, the right side of the "=" sign in formulas 1-5 above... Rounding is performed, leaving the rest unchanged. Rounding can be done up or down. Optionally, the rounded value must be divisible by 2, meaning it must be a multiple of 2. This ensures that the smallest time unit whose first time domain length is an integer multiple of 2.

[0150] This application should, as far as possible, ensure that the value of M is an integer, so that the first time-domain unit is the smallest time unit. Furthermore, the values ​​of the aforementioned coefficients can be between 0 and 1, which ensures that there is still sufficient useful signal even with decoding errors.

[0151] In one possible example, the intermediate preamble is placed at the beginning of the symbol; that is, the first time-domain interval between the preamble and the intermediate preamble, or between two adjacent intermediate preambles, is an integer number of symbols, such as N symbols, where N is an integer greater than or equal to 1. If the smallest time unit F used to determine M is one chip (i.e., F in the previous formulas 1-5 and various variations is one chip), then the unit of M is chips, and one symbol can carry A chips, where A is greater than 1. This means rounding down M / A. The first time-domain length between the preamble and the intermediate preamble is then M' chips, where M' = N * A. For example, if M = 10 and A = 4, then N = 2 and M' = 8.

[0152] In another possibility, the end of the preamble or the preceding intermediate preamble is not the end of a symbol. For example, the end of the preamble or the preceding intermediate preamble may be the A'-th chip in a symbol, thus leaving A-A' chips available in that symbol, resulting in... M'=N*A+AA ′ = (N+1)*AA′, this example reduces the value of M so that the starting position of the next intermediate preamble is at the beginning of the symbol.

[0153] The following describes Method 2, which determines the first time domain length based on the first SFO range (i.e., the first time domain length is determined based on the first difference between the upper and lower limits of the first SFO range).

[0154] The second communication device or third-party equipment can store the correlation between the difference between the upper and lower limits of the SFO range and the time domain length. This correlation can be expressed in a table, a formula, or other ways. After determining the first SFO range, the second communication device can determine the time domain length, i.e., the first time domain length, based on the first difference between the upper and lower limits of the first SFO. The second communication device can calculate the first time domain length based on the first difference using the following formula, or it can find the first time domain length by looking up a table based on the first difference.

[0155] In one possible example, the first difference between the first time domain length and the first SFO range satisfies the following formula 6:

[0156] For information on W, K, and F, please refer to the description in Formula 1; it will not be repeated here.

[0157] when It can be seen that the length of the first time domain can be determined based on the first difference of the first SFO range and the maximum time offset value a.

[0158] In one possible example, the first time domain length, the first difference of the first SFO range, and the maximum time offset satisfy the following formula 7 (i.e., ... Substituting into formula 6, we get formula 7):

[0159] In one possible example, the length of the first time domain is M minimum time units, i.e. Then the first difference between M and the first SFO range satisfies the following formula 8:

[0160] when At that time, M, the first difference of the first SFO range, and the maximum time offset satisfy the following formula 9 (that is, ... Substituting into formula 8, we get formula 9):

[0161] When W=10 6 With the smallest time unit being one chip, and one chip being 66.67µs, based on Equation 9, we can obtain the following Equation 10:

[0162] In one possible implementation, the above formula 6-10 can be modified in several ways as follows:

[0163] For example, the content on the right side of the "=" sign in formulas 6-10 above can be treated as a whole and rounded down. This can be done by rounding up or down, ensuring that the smallest time unit whose first time domain length is an integer multiple of the original length. For example, formula 10 can be transformed into: in, This indicates rounding down. Other formulas undergo similar transformations, which will not be elaborated further.

[0164] For example, the first difference in the first SFO range is 10. 4 ppm, with the first difference of 10 4 Substituting into formula 10, we get: When a = 33.33us, Approximately 50, M = 50, meaning the first time domain length is 50 chips.

[0165] For example, the first difference in the first SFO range is 5*10. 3 ppm, the first difference is 5*10 3 Substituting into formula 10, we get: When a = 33.33us, Approximately 100, M = 100, the first time domain length is 100 chips.

[0166] For example, consider the content on the right side of the equal sign "=" in the above formula 6-10 as a whole, round it down, and then multiply it by a coefficient. Rounding can be done up or down.

[0167] For example, consider the content on the right side of the equal sign "=" in formula 6-10 above as a whole, multiply it by a coefficient, and then round down. Rounding can be either up or down.

[0168] For example, consider the content on the right side of the "=" sign in the above formula 6-10 as a whole multiplied by a coefficient.

[0169] For example, the right side of the "=" sign in formula 6-10 above... Rounding is performed while the rest remains unchanged. Rounding can be done up or down. Optionally, the rounded value must be divisible by 2, meaning it must be a multiple of 2. This ensures that the smallest time unit whose length is an integer multiple of the first time domain length.

[0170] This application should, as far as possible, ensure that the value of M is an integer, so that the first time-domain unit is the smallest time unit. Furthermore, the values ​​of the aforementioned coefficients can be between 0 and 1, which ensures that there is still sufficient useful signal even with decoding errors.

[0171] In one possible example, the intermediate preamble is placed at the beginning of the symbol; that is, the first time-domain interval between the preamble and the intermediate preamble, or between two adjacent intermediate preambles, is an integer number of symbols, such as N symbols, where N is an integer greater than or equal to 1. If the smallest time unit F used to determine M is one chip (i.e., F in the previous formulas 6-10 and various variations is one chip), then the unit of M is chips, and one symbol can carry A chips, where A is greater than 1. This means rounding down M / A. The first time-domain length between the preamble and the intermediate preamble is then M' chips, where M' = N * A. For example, if M = 22 and A = 4, then N = 5 and M' = 20.

[0172] In another possibility, the end position of the preamble or the preceding intermediate preamble is not the end position of a symbol. For example, the end position of the preamble or the preceding intermediate preamble is the A'-th chip in a symbol, thus there are still A-A' chips available in that symbol, thereby obtaining... M'=N*A+AA ′ = (N+1)*AA′, this example reduces the value of M so that the starting position of the next intermediate preamble is at the beginning of the symbol.

[0173] The second communication device can determine the first time domain length using either method 1 or method 2. The first communication device also needs to know the first time domain length in order to perform time offset correction.

[0174] The following describes several examples of how the first communication device learns the length of the first time domain (the numbers in the examples below are for ease of description only and do not indicate the quality or priority of the examples):

[0175] Example 1.1: After determining the first time domain length using method 1 or method 2, the second communication device can indicate the first time domain length to the first communication device. For example, the second communication device sends a third signal, and correspondingly, the first communication device receives the third signal, wherein the third signal is used to indicate the first time domain length.

[0176] The order in which the second communication device sends the third signal to the first communication device and step 302 (the second device sends the second signal to the first device) is not restricted.

[0177] The following are several examples of a third signal indicating the length of the first time domain:

[0178] In one example: the third signal includes a first preamble, which is associated with the first time-domain length.

[0179] When the first communication device communicates with the second communication device, there are multiple types of preambles that can be used. This application specifies that a preamble is associated with a time-domain length (here, the time-domain length refers to the time-domain length between the preamble and the first intermediate preamble, and / or the time-domain length between the first intermediate preamble and the second intermediate preamble). Both the first and second communication devices can store the association between the preamble and the time-domain length.

[0180] For example, four types of preambles are allowed: preambles 0-3, corresponding to time-domain lengths of 5 chips, 10 chips, 15 chips, and 20 chips, respectively. The second communication device determines that the first time-domain length is 15 chips, and therefore carries preamble 2 in the third signal. After receiving the third signal, the first communication device can detect that the preamble carried in the third signal is preamble 2. The first communication device can determine that the time-domain length corresponding to preamble 2 is 15 chips, thus knowing that the preamble in the second signal in step 302 is 15 chips apart from the first intermediate preamble, and / or that the first intermediate preamble and the second intermediate preamble in the second signal are 15 chips apart.

[0181] In one example: the third signal includes a preamble and indication information, the indication information indicating the length of the first time domain, the indication information following the preamble, and an interval of K bits between the indication information and the preamble, where K is an integer greater than or equal to 0. This indication information may occupy one or more bits.

[0182] For example, the 2 bits after the preamble are used to indicate the first time domain length. For example, 00 indicates that the first time domain length is 5 chips, 01 indicates that the first time domain length is 10 chips, 10 indicates that the first time domain length is 15 chips, and 11 indicates that the first time domain length is 20 chips.

[0183] Example 1.2: The second communication device determines the first time domain length using method 1. The second communication device can indicate the first SFO range or the first associated value to the first communication device. The first communication device calculates the first time domain length using the same method as the second communication device. The method by which the second communication device indicates the first SFO range or the first associated value to the first communication device is similar to the method of indicating the first time domain length with the third signal described above, and will not be described in detail again.

[0184] Example 1.3: The second communication device uses method 2 to determine the first time domain length. The second communication device can inform the first communication device of the first difference of the first SFO. For example, the second communication device sends a fourth signal, and correspondingly, the first communication device receives the fourth signal, wherein the fourth signal is used to indicate the first difference. For example, the fourth signal includes a second preamble, which is associated with the first difference. As another example, the fourth signal includes a preamble and indication information, which indicates the first difference. The indication information is located after the preamble, and there is a K-bit interval between the indication information and the preamble, where K is an integer greater than or equal to 0. The way the fourth signal indicates the first difference is similar to the way the third signal indicates the first time domain length; they can be referred to interchangeably and will not be repeated here.

[0185] The order in which the second communication device indicates the first SFO range, the first associated value, or the first difference to the first communication device is not restricted from step 302 (the second device sends the second signal to the first device).

[0186] Furthermore, if the second communication device has limited capabilities and only supports one SFO precision (i.e., the difference between the upper and lower limits of the SFO), the second communication device can inform the first communication device of its capabilities (i.e., the supported SFO precisions), which is equivalent to informing the first communication device of the first difference. For example, if there are two SFO precisions, the second communication device can indicate one of the precisions using 1 bit. Alternatively, the communication device can be configured with two capabilities, such as high and low, for example, high capability corresponding to an SFO precision of 5*10. 3 ppm, the SFO precision corresponding to low capability is 10. 4 In ppm, the second communication device can use 1 bit to indicate its capability; for example, 1 bit being 0 indicates low capability, i.e., SFO precision is 10. 4 ppm; when 1 bit is 0, it indicates high capability, that is, SFO precision is 5*10. 3 ppm.

[0187] Example 1.4: The first communication device has a pre-configured first time domain length, which does not need to be informed by the second communication device. For example, the first time domain length is related to the capability of the second communication device, and the first time domain length can be determined based on method 2.

[0188] This application provides two methods for determining the first time domain length: Method 1 and Method 2. The second communication device can be pre-configured to determine the first time domain length using either Method 1 or Method 2. For example, all communication devices can be configured to determine the first time domain length using either Method 1 or Method 2. Alternatively, based on the capabilities of the communication device, it can be configured to determine the first time domain length using either Method 1 or Method 2. For instance, if the communication device supports compensation for sampling frequency deviation based on the upper or lower limit of the sampling frequency deviation range, it can be configured to determine the first time domain length using Method 2. If the communication device does not support compensation for sampling frequency deviation based on the upper or lower limit of the sampling frequency deviation range, it can be configured to determine the first time domain length using Method 1. Further optionally, the second communication device instructs the first communication device to determine the first time domain length using either Method 1 or Method 2.

[0189] In one possible implementation, the second communication device or a third party may pre-store multiple third time-domain lengths. After determining the first time-domain length based on the first SFO range, the second communication device can select a suitable time-domain length from the multiple third time-domain lengths as the final time-domain length. For ease of description, the selected suitable third time-domain length is referred to as the second time-domain length.

[0190] For example, the interval between the preamble and the first intermediate preamble in the second signal of step 302, which is a first time-domain length; and / or the interval between two adjacent intermediate preambles, which is a first time-domain length, can be replaced by: the interval between the preamble and the first intermediate preamble in the second signal, which is a second time-domain length; and / or the interval between two adjacent intermediate preambles, which is a second time-domain length. Wherein, the second time-domain length is: the third time-domain length among a plurality of pre-saved third time-domain lengths that is less than or equal to the first time-domain length and has the smallest difference from the first time-domain length.

[0191] Optionally, multiple pre-saved third time domain lengths can be spaced equally.

[0192] For example, the pre-saved third time domain lengths include 5 chips, 10 chips, 15 chips, and 20 chips. The first time domain length determined based on the first SFO range is 14 chips. Among the multiple third time domain lengths, the one closest to the first time domain length but smaller than the first time domain length is 10 chips, so the second time domain length is 10 chips.

[0193] In this example, the second time domain length does not exceed the first time domain length because the first time domain length determined based on the first SFO range is more accurate than the pre-saved third time domain length. The first time domain length can be understood as the maximum tolerance time for accumulated deviation. If the second time domain length exceeds the first time domain length, it will lead to more accumulated deviation and reduce the decoding accuracy.

[0194] If the preamble and the first intermediate preamble in the second signal are spaced apart by a second time domain length; and / or, two adjacent intermediate preambles are spaced apart by a second time domain length. For the first communication device, this second time domain length must also be known in order to perform time offset correction / sampling frequency correction.

[0195] The following are several examples of how the first communication device learns the length of the second time domain (the numbers in the examples below are for ease of description only and do not indicate the quality or priority of the examples):

[0196] Example 2.1: After determining the second time domain length, the second communication device indicates the second time domain length to the first communication device. For example, the second communication device sends a fifth signal, and correspondingly, the first communication device receives the fifth signal, which indicates the second time domain length. For instance, the fifth signal includes a third preamble, which is associated with the second time domain length. As another example, the fifth signal includes a preamble and indication information, which indicates the second time domain length. The indication information follows the preamble, and there is a K-bit interval between the indication information and the preamble, where K is an integer greater than or equal to 0. The way the fifth signal indicates the second time domain length is similar to the way the third signal indicates the first time domain length, and they can be referenced interchangeably; further details are omitted here. In this example, the preset value or number of third time domain lengths is limited, making it easier to inform the other end compared to the first time domain length, thus saving the overhead of the second communication device indicating to the first communication device.

[0197] Example 2.2: The second communication device determines the first time domain length based on method 1 or method 2, and the second communication device indicates the first time domain length to the first communication device. The first communication device stores multiple third time domain lengths, and the first communication device selects a suitable third time domain length, i.e., the second time domain length, from the multiple third time domain lengths based on the first time domain length in the same way as the second communication device.

[0198] Example 2.3: The second communication device determines the first time domain length based on method 1, and the second communication device indicates the first SFO range or the first associated value to the first communication device. The first communication device stores multiple third time domain lengths. After determining the first time domain length using the same method as the second communication device, the first communication device then selects a suitable third time domain length, i.e., the second time domain length, based on the first time domain length using the same method as the second communication device.

[0199] Example 2.4: The second communication device determines the first time domain length based on method 2, and the second communication device indicates the first difference of the first SFO range to the first communication device. The first communication device stores multiple third time domain lengths. After determining the first time domain length using the same method as the second communication device, the first communication device then selects a suitable third time domain length, i.e., the second time domain length, based on the first time domain length using the same method as the first communication device.

[0200] The order in which the second communication device indicates the second time domain length, or the first time domain length, or the first SFO range, or the first correlation value, or the first difference to the first communication device is not restricted from step 302 (the second device sends the second signal to the first device).

[0201] Figure 6, in conjunction with Figure 3 and the second time domain length, presents a flowchart of a communication method.

[0202] Step 601: The first communication device sends a first signal, and correspondingly, the second communication device receives the first signal.

[0203] Step 602: The second communication device can determine the first SFO range based on the first signal, and then determine the first time domain length based on the first SFO range.

[0204] Step 603: The second communication device selects a suitable time domain length, namely the second time domain length, from a plurality of pre-saved third time domain lengths based on the first time domain length.

[0205] Step 604: The second communication device sends a signal, and correspondingly, the first communication device receives a signal, the signal being used to indicate the second time domain length.

[0206] Step 605: The second communication device sends a second signal, and correspondingly, the first communication device receives the second signal. The second signal includes a preamble and at least one intermediate preamble, with a second time-domain length separating the preamble and the first intermediate preamble; and / or, the second signal includes at least two intermediate preambles, with a second time-domain length separating adjacent intermediate preambles.

[0207] Step 606: The first communication device performs time offset correction / sampling frequency correction based on the second time domain length.

[0208] For example, the first communication device performs time offset correction / sampling frequency correction based on the second time domain length, the number of samples between the preamble and the first intermediate preamble in the second signal, and / or, based on the number of samples between the first preamble and the second intermediate preamble in the second signal. The process of time offset correction / sampling frequency correction performed by the first communication device based on the first time domain length in step 606 is similar to that in step 303, and will not be repeated here.

[0209] In one possible implementation, the first time-domain length is determined based on method 2 (i.e., the first time-domain length is determined based on the first difference between the upper and lower limits of the first SFO range). In step 302, when the second communication device transmits the second signal, it can compensate for the SFO. That is, the second signal in step 302 is transmitted after compensating for the sampling frequency deviation according to the upper or lower limit of the first sampling frequency deviation range. After the second communication device compensates for the SFO between the second communication device and the first communication device, the remaining SFO is within the maximum allowable deviation range, for example, [-c, c] or [0, c], where c is the precision. After compensation, transmitting the second signal can be applied to scenarios where the preamble and the first intermediate preamble of the second signal are spaced apart by the first time-domain length; and / or, where two adjacent intermediate preambles are spaced apart by the first time-domain length. It can also be applied to scenarios where the preamble and the first intermediate preamble of the second signal are spaced apart by the second time-domain length; and / or, where two adjacent intermediate preambles are spaced apart by the second time-domain length.

[0210] For example, the first communication device sends X chips (e.g., the first signal in step 301 occupies X chips), and the duration of each chip is the duration corresponding to N sampling points as determined by the first communication device. The second communication device receives these chips, using 1.052*X*N sampling points. The second communication device can identify that the range of SFO is [5x10]. 4 ppm, 6x10 4 [ppm], the second communication device can compensate based on the absolute value of the upper or lower limit of this range. That is, when the second communication device sends the second signal, it uses the duration corresponding to 1.05N or 1.06N sampling points as the duration of one chip, thus compensating for the remaining deviation. 4 ppm.

[0211] For example, the first communication device sends X chips (e.g., the first signal in step 301 occupies X chips), and the duration of each chip is the duration corresponding to N sampling points as determined by the first communication device. The second communication device receives these chips, using 0.932*X*N sampling points. The second communication device can identify that the SFO range is [-7x10]. 4 ppm, -6x10 4 [ppm], the second communication device can compensate based on the absolute value of the upper or lower limit of this range. That is, when the second communication device sends the second signal, it compensates by taking the duration corresponding to 0.93N or 0.94N sampling points as the duration of one chip. In this way, the remaining deviation should not exceed 10. 4 ppm.

[0212] Example 2:

[0213] Figure 7 shows a flowchart illustrating a communication method.

[0214] Step 701: The first communication device sends a sixth signal, the sixth signal including: a preamble and at least two intermediate preambles, the preamble and the first intermediate preamble being spaced apart by a fourth time domain length; the first intermediate preamble and the second intermediate preamble being spaced apart by a fifth time domain length, the fifth time domain length being N times the fourth time domain length, where N is a positive integer greater than or equal to 1, and N is determined based on the difference between the upper limit and the lower limit of the supported sampling frequency deviation range.

[0215] As shown in Figure 4c, there is a gap of M chips (i.e., the fourth time domain length) between the preamble and the first intermediate preamble, and a gap of M*N chips (i.e., the fifth time domain length) between the first intermediate preamble and the second intermediate preamble.

[0216] The second communication device can receive the preamble, the first intermediate preamble, and the second intermediate preamble in the sixth signal.

[0217] Optionally, in step 702: after receiving the first intermediate preamble in the sixth signal, the second communication device performs time offset correction (i.e., compensates for the SFO) based on the first intermediate preamble and the fourth time domain length in the sixth signal, and receives the content after the first intermediate preamble based on the corrected time offset (i.e. the compensated SFO).

[0218] After compensating for SFO, the remaining SFO is within the maximum allowable deviation range.

[0219] For example, the second communication device performs time offset correction / sampling frequency correction based on the fourth time domain length and the number of samples between the preamble and the first intermediate preamble in the sixth signal. This process is similar to that described in step 303 and will not be repeated in detail.

[0220] Further optional, step 703: After receiving the second intermediate preamble in the sixth signal, the second communication device performs time offset correction based on the second intermediate preamble and the fifth time domain length in the sixth signal (that is, on the basis of the compensation in step 702, the SFO is compensated again), and receives the content after the second intermediate preamble based on the corrected time offset (that is, the compensated SFO).

[0221] For example, the second communication device performs time offset correction / sampling frequency correction based on the fifth time domain length and the number of samples between the first intermediate preamble and the second intermediate preamble in the sixth signal. This process is similar to that described in step 303 and will not be repeated in detail.

[0222] For the transmitting end (i.e., the first communication device), it is assumed that after receiving the first intermediate preamble, the receiving end will perform time offset correction (i.e., compensation), and receive the content after the first intermediate preamble based on the corrected time offset. After compensation, if the remaining offset is small, the transmitting end can place the next intermediate preamble after a longer time interval. That is, the fifth time domain length between the second and first intermediate preambles can be greater than the fourth time domain length.

[0223] The fifth time-domain length can be determined based on the actual range of the SFO (Signal Optimizer), ensuring a suitable time-domain interval between preambles. This effectively corrects time offsets, guarantees correct decoding, and avoids excessive preamble density that would increase overhead. However, while the upper or lower limit, or the difference between the upper and lower limits of the actual SFO range are integers, the actual SFO may not be an integer. This makes determining the fifth time-domain length based on the actual SFO more computationally complex than determining it based on the actual SFO range. In other words, determining the fifth time-domain length based on the actual SFO range is computationally simpler. Furthermore, the difference between the upper and lower limits of the SFO is usually fixed; using the difference to determine the fifth time-domain length further simplifies the computation compared to using either the upper or lower limit.

[0224] Both the first and second communication devices can determine the fourth time domain length. Several examples of determining the fourth time domain length are described below: In one example, the fourth time domain length is determined using the method described in Embodiment 1 for determining the first or second time domain length. That is, the fourth time domain length can be considered as the first or second time domain length in Embodiment 1. In another example, the fourth time domain length is determined based on the maximum SFO value. For example, the maximum SFO is 10. 5 ppm means the maximum deviation is 10%. For example, the maximum time deviation is 0.3 μs, the minimum time unit (e.g., one chip) is 2 μs, and one minimum time unit introduces a maximum sampling time deviation of 0.2 μs. Five minimum time units are used to place one intermediate preamble, that is, the fourth time length is five minimum time units, for example, five chips.

[0225] Both the first and second communication devices can determine the multiple N. Several examples of determining the multiple N are described below:

[0226] In one example, N is determined based on the precision of the supported SFO range (i.e., the difference between the upper and lower limits), for example, N is the maximum SFO (e.g., 10). 5 The ratio of the accuracy of (ppm) to the accuracy of the supported SFO range. For example, the SFO range is (10 ppm). 4 ppm, 2*10 4[ppm], meaning the supported precision is 10. 4 ppm, then

[0227] As shown in Figure 4d, there is a 5-chip gap between the preamble and the first intermediate preamble, and a 50-chip gap between the first intermediate preamble and the second intermediate preamble.

[0228] In another example, as mentioned above, the largest SFO (e.g., 10) 5 The ppm value is fixed, and the accuracy of the supported SFO range is also predictable, so the N value is fixed and can be pre-configured or factory set.

[0229] In one possible example, the first communication device sends a sixth signal. After detecting the first intermediate preamble, the second communication device can determine the range of the SFO based on the fourth time-domain length of the interval between the first intermediate preamble and the preamble. For example, the maximum correction range can be obtained based on the duration of the first intermediate preamble sequence, and the accuracy range can be obtained based on the duration of the first intermediate preamble sequence or the number of chips between the first intermediate preamble and the preamble. Alternatively, if the accuracy of the SFO range is pre-configured in both the second and first communication devices, no calculation is required.

[0230] If the sixth signal includes at least three intermediate preambles, the second and third intermediate preambles can be spaced by a fifth time-domain length (e.g., M*N chips), or by a time-domain length longer or shorter than the fifth time-domain length. For example, the time-domain length between the third and second intermediate preambles can be further determined based on the measurement accuracy of the second intermediate preamble over a period of time (i.e., the difference between the upper and lower limits of the SFO range that can be measured) or the accuracy of the supported SFO range. This is not limited in the embodiments of this application.

[0231] In one possible implementation, the first and second communication devices can store the fifth time domain length for a period of time. During this period of "new transmission", the interval between the preamble and the first intermediate preamble can be the fifth time domain length, and / or the interval between two adjacent intermediate preambles can also be the fifth time domain length.

[0232] For example, after the sixth signal, the first communication device sends the seventh signal, and correspondingly, the second communication device receives the seventh signal; or, the second communication device sends the seventh signal, and the first communication device receives the seventh signal. The time interval between the seventh signal and the sixth signal is less than or equal to the first time interval. For example, the first time interval is one day or one week. The seventh signal includes a preamble and at least one intermediate preamble, with the preamble and the first intermediate preamble separated by the fifth time domain length; further optionally, adjacent intermediate preambles in the seventh signal are separated by the fifth time domain length. After determining the fifth time domain length, using the fifth time domain length for a shorter time (i.e., the first time interval) can reduce the computational load. Furthermore, the fifth time domain length is longer than the fourth time domain length, allowing for sparser placement of intermediate preambles and lower overhead.

[0233] The duration of the interval between the seventh signal and the sixth signal can be one of the following: Specifically, the sixth signal can be: the start or end position of the last preamble (which can be an intermediate preamble or a follower preamble) in the sixth signal, or the end position of the sixth signal, or a position in the sixth signal at a predetermined distance from the end position (this position is before the end position and can be applied to scenarios where the sixth signal does not include a follower preamble), the start position of the sixth signal, or a position in the sixth signal at a predetermined distance from the start position (this position is after the start position). Specifically, the seventh signal can be: the start or end position of the first preamble in the seventh signal, or the start position of the seventh signal, or a position in the seventh signal at a predetermined distance from the start position (this position is after the start position), or the end position of the seventh signal, or a position in the seventh signal at a predetermined distance from the end position (this position is before the end position and can be applied to scenarios where the seventh signal does not include a follower preamble). As a specific example, the duration of the interval between the end position of the last preamble in the sixth signal and the start position of the first preamble in the seventh signal is less than or equal to a second duration.

[0234] In one possible example, a second duration is set, for example, a second duration that is multiple times the length of the fifth time domain, and much shorter than the first duration. The second duration can be understood as the maximum tolerable duration for correct decoding during the accumulation of time offsets; that is, beyond the second duration, the accumulated time offset becomes too large, increasing the probability of decoding errors. If the interval between the seventh signal and the sixth signal is less than or equal to the second duration after the sixth signal, the seventh signal may not include a preamble but may include at least one intermediate preamble. For example, the seventh signal may begin with the first intermediate preamble, or the seventh signal may begin with the data portion and then, after a certain period, include the first intermediate preamble. In this example, after receiving the sixth signal, the second communication device can perform time offset correction based on the last preamble in the sixth signal. Within a short period after the sixth signal (i.e., within the second duration), synchronization without a preamble is not required, omitting the transmission of the preamble reduces signal overhead.

[0235] Example 3:

[0236] Figure 8 shows a flowchart of a communication method.

[0237] Step 801: The first communication device sends the eighth signal, and correspondingly, the second communication device receives the eighth signal.

[0238] The eighth signal includes an intermediate preamble and / or a post-preamble; optionally, the eighth signal may also include a preamble.

[0239] Optionally, in step 802: the second communication device performs time offset correction based on the preamble (e.g., intermediate preamble and / or post-preamble) included in the eighth signal.

[0240] For example, time offset correction can be performed based on the last preamble included in the eighth signal. The last preamble can be an intermediate preamble or a post-preamble.

[0241] Step 803a: The first communication device sends the ninth signal, and correspondingly, the second communication device receives the ninth signal.

[0242] Step 803b: The second communication device sends the ninth signal, and correspondingly, the first communication device receives the ninth signal.

[0243] Steps 803a and 803b can be performed.

[0244] The ninth signal does not include a preamble, and the time interval between the ninth signal and the eighth signal is less than or equal to the second time interval. The second time interval can be understood as the maximum tolerable time interval for correct decoding during the accumulation of time offsets. In other words, when the second time interval is exceeded, the accumulation of time offsets becomes too large, and the probability of decoding errors increases.

[0245] It should be noted that there are no other signals between the eighth and ninth signals; in other words, the ninth signal is the first signal transmitted after the eighth signal.

[0246] The duration of the interval between the eighth and ninth signals can be one of the following: The eighth signal can specifically be: the start or end position of the last preamble (which can be an intermediate or subsequent preamble) in the eighth signal, or the end position of the eighth signal, or a position in the eighth signal at a predetermined distance from the end position (this position is before the end position and can be applied to scenarios where the eighth signal does not include a subsequent preamble), the start position of the eighth signal, or a position in the eighth signal at a predetermined distance from the start position (this position is after the start position). The ninth signal can specifically be: the start or end position of the first preamble in the ninth signal, or the start position of the eighth signal, or a position in the ninth signal at a predetermined distance from the start position (this position is after the start position), or the end position of the ninth signal, or a position in the ninth signal at a predetermined distance from the end position (this position is before the end position and can be applied to scenarios where the ninth signal does not include a subsequent preamble). As a specific example, the duration of the interval between the end position of the last preamble in the eighth signal and the start position of the first preamble in the ninth signal is less than or equal to a second duration.

[0247] When Embodiments 2 and 3 are combined, the second duration is many times the length of the fifth time domain, and the second duration is much shorter than the first duration. The eighth signal can be regarded as the sixth signal in Embodiment 2, and the ninth signal can be regarded as the seventh signal in Embodiment 2.

[0248] As shown in Figure 9a, three possible scenarios are presented: Scenario 1: The time interval between the end position of the eighth signal and the end position of the ninth signal is less than the second time interval, and the ninth signal may not include any preamble (e.g., preamble, intermediate preamble, postamble). Scenario 2: The time interval between the end position of the eighth signal and the start position of the ninth signal is less than the second time interval, but the time interval between the end positions of the eighth signal and the end positions of the ninth signal is greater than the second time interval, and the ninth signal does not include a preamble but includes at least one intermediate preamble. Scenario 3: The time interval between the end position of the eighth signal and the start position of the ninth signal is greater than the second time interval, and the start position of the ninth signal is a preamble.

[0249] In this example, after receiving the eighth signal, the second communication device can perform time offset correction based on the preamble (which may be the last preamble) included in the eighth signal. Within a short period of time after the eighth signal (i.e., within the second duration), synchronization can be performed without a preamble, thus reducing signal overhead by omitting the transmission of the preamble.

[0250] In one possible example, the ninth signal does not include a preamble but includes at least one intermediate preamble; that is, the ninth signal begins with a data portion, followed by an intermediate preamble after a certain period (i.e., case 2 in Figure 7). The duration of the interval between the first intermediate preamble included in the ninth signal and the eighth signal is less than or equal to a second duration, and / or, the duration of the interval between the first intermediate preamble included in the ninth signal and the eighth signal is greater than or equal to a third duration, which is the second duration minus a minimum time unit. A minimum time unit can be a chip or a symbol.

[0251] The duration of the interval between the first intermediate preamble and the eighth signal can have the following possibilities: The eighth signal can specifically be: the start or end position of the last preamble (which can be an intermediate preamble or a follower preamble) in the eighth signal, or the end position of the eighth signal, or a position in the eighth signal that is a preset distance from the end position (this position is before the end position and can be applied to scenarios where the eighth signal does not include a follower preamble). The first intermediate preamble can specifically be: the start or end position of the first intermediate preamble.

[0252] As shown in Figure 9b, the last preamble in the eighth signal is the post-preamble, the beginning of the ninth signal is the data part, and the first intermediate preamble follows the data part. The time interval between the end position of the post-preamble in the eighth signal and the first intermediate preamble in the ninth signal is less than the second time interval and greater than the third time interval.

[0253] The second duration, as described above, can be understood as the maximum tolerable duration for correct decoding during the accumulation of time offsets. In other words, exceeding the second duration leads to excessive time offset accumulation and increases the probability of decoding errors. Therefore, the intermediate preamble must be placed no later than the second duration. Consequently, the time interval between the first intermediate preamble in the ninth signal and the eighth signal is less than the second duration. Within the second duration, the later the intermediate preamble is placed, the lower the signal overhead.

[0254] In actual transmission, the transmission interval between the eighth and ninth signals may be an integer multiple of the minimum time unit or a non-integer multiple of the minimum time unit, such as 2.5 minimum time units, 6 minimum time units, etc. Let duration *a* be the transmission interval between the eighth and ninth signals, and duration *a* includes *v* minimum time units, for example, *v* is 2.5 or 6. The sum of duration *a* and a minimum time unit is less than the second duration. Assuming the second duration includes *G* minimum time units, then within the second duration, the ninth signal can occupy *Gv* minimum time units. It can be understood that any signal is transmitted with the duration of a minimum time unit; that is, the first intermediate preamble in the ninth signal is placed at the beginning of a minimum time unit in the ninth signal.

[0255] If v is not an integer, if the intermediate precode is placed in the ninth signal... If the starting position of the smallest time unit is determined by the time interval between the starting position of the intermediate preamble and the ending position of the eighth signal, the time interval will be greater than the second time interval. This will lead to an excessively large cumulative deviation. Therefore, the intermediate preamble is placed in the ninth signal. The starting position of each smallest time unit. To round down, Round up to the nearest whole number.

[0256] Example 4:

[0257] In step 303 of Embodiment 1, it was described that after receiving the second signal, the first communication device can perform time offset correction / sampling frequency correction based on the first time domain length. For example, after time offset correction / sampling frequency correction, the first communication device can decode the data after the first intermediate preamble in the second signal, or send a signal to the second communication device, or receive a signal from the second communication device. However, how the time offset between the preamble and the first intermediate preamble is corrected is not described in detail. Based on this, Embodiment 4 describes how to perform time offset correction on previously received data based on the intermediate preamble or postamble in any signal.

[0258] As shown in Figure 2a, the clock at the receiving end runs slower than the clock at the transmitting end, and the sampling frequency at the receiving end is lower than the sampling frequency at the transmitting end. Therefore, the minimum time unit detected by the receiving end is shorter than the minimum time unit used by the transmitting end.

[0259] Let x be the amount of data sent by the sender in the i-th smallest time unit. i Ignoring noise and without SFO, the data received by the receiver in the i-th minimum time unit is x. i .

[0260] Assume SFO is -10 5ppm means that within each minimum time unit, the deviation backward (in terms of time) is 10%. Therefore, the data received by the receiver in the first minimum time unit is 0.9x1, the data received in the second minimum time unit is 0.1x1+0.8x2, the data received in the third minimum time unit is 0.2x2+0.7x3, and so on.

[0261] Based on this, the noise in the i-th smallest time unit is set to n. i Then the data y received by the receiving end in the i-th time unit i The following formulas are satisfied: 0.9x1 + n1 = y1; corresponding to the first minimum time unit; 0.1x1 + 0.8x2 + n2 = y2; corresponding to the second minimum time unit; 0.2x2 + 0.7x3 + n3 = y3; 0.3x3 + 0.6x4 + n4 = y4; 0.4x4 + 0.5x5 + n5 = y5; 0.5x5 + 0.4x6 + n6 = y6; 0.6x6 + 0.3x7 + n7 = y7; 0.7x7 + 0.2x8 + n8 = y8; 0.8x8 + 0.1x9 + n9 = y9; 0.9x9 + n 10 =y 10 ; This corresponds to the tenth smallest time unit.

[0262] As shown in Figure 2b, the clock at the receiving end runs faster than the clock at the transmitting end, and the sampling frequency at the receiving end is higher than that at the transmitting end. Therefore, the minimum time unit detected by the receiving end is longer than the minimum time unit used by the transmitting end.

[0263] Let x be the amount of data sent by the sender in the i-th smallest time unit. i Ignoring noise and without SFO, the data received by the receiver in the i-th minimum time unit is x. i .

[0264] Assume SFO is +10 5 ppm means that within each minimum time unit, the forward (time-wise) deviation is 10%. Therefore, the data received by the receiver in the first minimum time unit is x1+0.1x2, the data received in the second minimum time unit is 0.9x2+0.2x3, the data received in the third minimum time unit is 0.8x3+0.3x4, and so on.

[0265] Based on this, the noise in the i-th smallest time unit is set to n. i Then the data y received by the receiving end in the i-th time unit iThe following formulas are satisfied: x1 + 0.1x2 + n1 = y1; (corresponding to one smallest time unit); 0.9x2 + 0.2x3 + n2 = y2; (corresponding to the second smallest time unit); 0.8x3 + 0.3x4 + n3 = y3; 0.7x4 + 0.4x5 + n4 = y4; 0.6x5 + 0.5x6 + n5 = y5; 0.5x6 + 0.6x7 + n6 = y6; 0.4x7 + 0.7x8 + n7 = y7; 0.3x8 + 0.8x9 + n8 = y8; 0.2x9 + 0.9x 10 +n9=y9; 0.1x 10 +x 11 +n 10 =y 10 (Corresponding to the tenth smallest time unit).

[0266] The communication device is configured such that the interval between the preamble and the intermediate preamble, or between the preamble and the postamble, is H minimum time units, where H is an integer greater than 1, and the minimum time unit can be a chip or a symbol; the noise is very small and has little impact on the data.

[0267] Figure 10 shows a flowchart illustrating a communication method.

[0268] Step 101: The communication device receives the preamble for synchronization. After synchronization, it determines the sampling result within each minimum time unit based on the sampling points (e.g., the data y in the formula above). i ).

[0269] A sampling point refers to multiple points collected within a minimum time unit based on the sampling frequency. Each minimum time unit contains a large number of sampling points. If the storage capacity of the communication device is limited, the communication device will not store every single sampling point, but can store the sampling results within each minimum time unit.

[0270] Step 102: After H minimum time units, the communication device synchronizes according to the intermediate preamble or the post-preamble and knows the cumulative time offset between the preamble and the preamble during this period.

[0271] Step 103: The communication device divides the cumulative time offset into R minimum time units for sampling result correction, where R is an integer greater than or equal to 1.

[0272] If a preamble (e.g., an intermediate preamble or a post-preamble) is expected to be received in the Rth minimum time unit, due to the sampling time offset at the receiver, the receiver needs to sample in the (R+1)th minimum time unit. Preamble detection is performed in the (R-1)th and (R+1)th minimum time units. There will be a portion of midamble / postamble signal on the (R-1)th or (R+1)th chip. The waveform changes of this portion of the signal need to be stored (e.g., stored in the Receiver). Based on the sampling results of the remaining midamble / postamble, the strength of this portion of the midamble / postamble signal is estimated and then substituted into the sampling results of the Hth or (H+1)th minimum time unit to derive the sampling results in the last minimum time unit.

[0273] It is understood that, in order to achieve the functions in the above embodiments, the first communication device and the second communication device include hardware structures and / or software modules corresponding to each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0274] Figures 11 and 12 are schematic diagrams of possible communication devices provided in embodiments of this application. These communication devices can be used to implement the functions of the first or second communication device in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0275] As shown in Figure 11, the communication device 1100 includes a processing unit 1110 and a transceiver unit 1120.

[0276] For example, the communication device 1100 is used to implement the functions of the communication device (e.g., the first communication device or the second communication device) in the method embodiments shown in Figures 3, 6, 7, 8, and 10. The transceiver unit 1120 can perform the receiving and sending actions performed by the communication device in the above method embodiments. The processing unit 1110 can perform other actions besides the sending and receiving actions performed by the communication device in the above method embodiments.

[0277] For example, when the communication device 1100 is used to implement the function of the second communication device in the method embodiment shown in FIG3, the transceiver unit 1120 is used to receive a first signal and send a second signal. The processing unit 1110 is used to parse the first signal, generate the second signal, determine a first SFO range based on the first signal, and determine a first time domain length based on the first SFO range.

[0278] A more detailed description of the processing unit 1110 and the transceiver unit 1120 can be obtained directly from the relevant descriptions in the method embodiments shown in Figures 3, 6, 7, 8, and 10, and will not be repeated here. The processing unit 1110 can be implemented by a processor, and the transceiver unit 1120 can be implemented by a transceiver.

[0279] 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 is understood that the interface circuit 1220 can be a transceiver or an input / output interface. Optionally, the communication device 1200 may also include a memory 1230 for storing instructions executed by the processor 1210, or storing input data required for the processor 1210 to execute instructions, or storing data generated after the processor 1210 executes instructions. Sometimes, the interface circuit 1220 can also be understood as part of the processor 1210, in which case the communication device 1200 includes the processor 1210.

[0280] When the communication device 1200 is used to implement the methods shown in Figures 3, 6, 7, 8 and 10, the processor 1210 is used to implement the functions of the processing unit 1110, and the interface circuit 1220 is used to implement the functions of the transceiver unit 1120.

[0281] When the aforementioned communication device is a chip applied to a terminal device, the terminal device chip implements the functions of the terminal device in the above method embodiments. The terminal device chip receives information from a network device, which can be understood as the information being first received by other modules (such as an RF module or antenna) in the terminal device, and then sent to the terminal device chip by these modules. The terminal device chip sends information to a network device, which can be understood as the information being first sent to other modules (such as an RF module or antenna) in the terminal device, and then sent to the network device by these modules.

[0282] When the aforementioned communication device is a chip applied to a network device, the network device chip implements the functions of the network device in the above method embodiments. The network device chip receives information from the terminal device, which can be understood as the information being first received by other modules (such as radio frequency modules or antennas) in the network device, and then sent to the network device chip by these modules. The network device chip sends information to the terminal device, which can be understood as the information being sent down to other modules (such as radio frequency modules or antennas) in the network device, and then sent to the terminal device by these modules. Here, the network device module can be the baseband chip of the network device, or a DU (Digital Unit) or other modules. The DU here can be a DU under the Open Radio Access Network (O-RAN) architecture.

[0283] In this application, entity A sends information to entity B, either directly or indirectly through other entities. Similarly, entity B receives information from entity A, either directly or indirectly through other entities. Entities A and B can be network devices or terminal devices, or modules within network devices or terminal devices. The sending and receiving of information can be between network devices and terminal devices, between two network devices (e.g., CU and DU), or between different modules within a single device (e.g., a terminal device chip and other modules within the terminal device, or a network device chip and other modules within the network device).

[0284] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0285] This application also provides a computer-readable storage medium storing a computer program that, when executed by a computer, enables the computer to perform the aforementioned communication method. Alternatively, the computer program includes instructions for implementing the aforementioned communication.

[0286] This application also provides a computer program product, including: computer program code, which, when run on a computer, enables the computer to execute the communication method provided above.

[0287] This application also provides a communication system, which includes a first communication device and a second communication device for performing the above-described communication method.

[0288] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, compact disc read-only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. Of course, the processor and storage medium can also exist as discrete components in the base station or terminal.

[0289] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially 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 instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a first control plane network element, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0290] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0291] In this application embodiment, the number of nouns, unless otherwise specified, refers to "singular nouns or plural nouns," that is, "one or more." "At least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A or B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. For example, A / B means: A or B. Expressions such as "at least one of the following" or "one or more of them" refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and / or c, or one or more of a, b and / or c, means: a, b, c, a and b, a and c, b and c, or a and b and c. Each of a, b, and c can be single or multiple.

[0292] The ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. Furthermore, such names do not indicate differences in the content, sending / receiving end, sending order, size, application scenario, priority, or importance of the two pieces of information. Additionally, the numbering of steps in the various embodiments described in this application is only to distinguish different steps and is not used to limit the order of steps.

Claims

1. A communication method, characterized in that, include: Receive the first signal; A second signal is transmitted; the second signal includes a preamble and at least one intermediate preamble, the preamble and the first intermediate preamble being spaced apart by a first time domain length; and / or, the second signal includes at least two intermediate preambles, adjacent two intermediate preambles being spaced apart by a first time domain length; the first time domain length is determined according to a first sampling frequency deviation range, the first sampling frequency deviation range being determined according to the first signal.

2. The method as described in claim 1, characterized in that, The first time domain length is determined based on the first sampling frequency deviation range, including: The first time domain length is determined based on a first correlation value of the first sampling frequency deviation range, wherein the first correlation value is the absolute value of the upper limit or the absolute value of the lower limit.

3. The method as described in claim 2, characterized in that, The first time domain length is determined based on a first correlation value of the first sampling frequency deviation range, including: The first time domain length is determined based on the first correlation value and the maximum sampling time bias value.

4. The method as described in claim 3, characterized in that, The first time domain length includes M minimum time units; The first correlation value, the maximum sampling time bias, and M satisfy the following formula: or Where F is the duration of the smallest time unit, and a is the maximum sampling time offset. This indicates rounding down to the nearest integer.

5. The method according to any one of claims 2-4, characterized in that, Also includes: A third signal is sent, which is used to indicate the length of the first time domain.

6. The method as described in claim 5, characterized in that, The third signal includes a first preamble, which is associated with the first time-domain length; or... The third signal includes a preamble and indication information. The indication information is used to indicate the length of the first time domain. The indication information is located after the preamble, and there is a K-bit interval between the indication information and the preamble, where K is an integer greater than or equal to 0.

7. The method as described in claim 1, characterized in that, The first time domain length is determined based on the first sampling frequency deviation range, including: The first time domain length is determined based on the first difference between the upper limit and the lower limit of the first sampling frequency deviation range.

8. The method as described in claim 7, characterized in that, The first time domain length is determined based on the first difference, including: The first time domain length is determined based on the first difference and the maximum sampling time bias.

9. The method as described in claim 8, characterized in that, The first time domain length includes M minimum time units; The first difference, the maximum sampling time bias, and M satisfy the following formula: or Where F is the duration of the smallest time unit, and a is the maximum sampling time offset. This indicates rounding down to the nearest integer.

10. The method according to any one of claims 7-9, characterized in that, Also includes: A fourth signal is sent, which is used to indicate the first difference or the first time domain length.

11. The method according to any one of claims 7-10, characterized in that, The second signal is sent after compensating for the sampling frequency deviation based on the upper or lower limit of the first sampling frequency deviation range.

12. The method according to any one of claims 1-4, 6-9 and 11, characterized in that, The preamble and the first intermediate preamble are spaced apart by a first time-domain length; and / or, adjacent intermediate preambles are spaced apart by a first time-domain length, including: The preamble and the first intermediate preamble are spaced apart by a second time domain length; and / or, two adjacent intermediate preambles are spaced apart by a second time domain length; wherein the second time domain length is: the third time domain length among a plurality of pre-saved third time domain lengths that is less than or equal to the first time domain length and has the smallest difference from the first time domain length.

13. The method as described in claim 12, characterized in that, Also includes: A fifth signal is sent, which is used to indicate the second time domain length.

14. The method according to any one of claims 1-13, characterized in that, When the second signal includes a preamble and two intermediate preambles, and the preamble and the first intermediate preamble are spaced apart by a first time domain length, the first intermediate preamble and the second intermediate preamble are spaced apart by N times the first time domain length, where N is a positive integer greater than or equal to 1, and N is determined according to the accuracy of the supported sampling frequency deviation range.

15. A communication method, characterized in that, include: Sending or receiving a sixth signal, the sixth signal including a preamble and at least two intermediate preambles, the preamble and the first intermediate preamble being spaced apart by a fourth time domain length; the first intermediate preamble and the second intermediate preamble being spaced apart by a fifth time domain length, the fifth time domain length being N times the fourth time domain length, where N is a positive integer greater than or equal to 1, and N is determined based on the difference between the upper and lower limits of the supported sampling frequency deviation range.

16. The method as described in claim 15, characterized in that, Also includes: Sending or receiving a seventh signal, the seventh signal including a preamble and at least one intermediate preamble, the preamble and the first intermediate preamble being spaced apart by the fifth time domain length; the time interval between the seventh signal and the sixth signal is less than or equal to the first time length.

17. The method as described in claim 15 or 16, characterized in that, The fourth time domain length is determined based on the maximum sampling frequency deviation value.

18. The method according to any one of claims 15-17, characterized in that, N is determined based on the difference between the upper and lower limits of the supported SFO range.

19. A communication method, characterized in that, include: Sending or receiving an eighth signal, the eighth signal including an intermediate preamble and / or a post-preamble; Sending or receiving a ninth signal, the ninth signal excluding a preamble, the duration of the interval between the ninth signal and the eighth signal being less than or equal to a second duration.

20. The method as described in claim 19, characterized in that, The time interval between the ninth signal and the eighth signal is less than or equal to the second time interval, including: The time interval between the ninth signal and the last preamble of the eighth signal is less than or equal to the second time interval.

21. The method as described in claim 19 or 20, characterized in that, The ninth signal includes at least one intermediate preamble; the duration of the interval between the first intermediate preamble and the eighth signal is less than or equal to the second duration and / or greater than or equal to the third duration, wherein the third duration is the second duration minus a minimum time unit.

22. A communication device, characterized in that, Includes a module for performing the method as described in any one of claims 1-21.

23. A communication device, characterized in that, Includes a processor, which is coupled to a memory; The memory is used to store computer programs or instructions; The processor is configured to execute some or all of the computer programs or instructions in the memory, and when the some or all of the computer programs or instructions are executed, to implement the method as described in any one of claims 1-21.

24. A communication device, characterized in that, Including processor and memory; The memory is used to store computer programs or instructions; The processor is configured to execute some or all of the computer programs or instructions in the memory, and when the some or all of the computer programs or instructions are executed, to implement the method as described in any one of claims 1-21.

25. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method as described in any one of claims 1-21.

26. A computer program product, characterized in that, The computer program product includes: computer instructions that, when executed on a computer, cause the method as described in any one of claims 1-21 to be implemented.

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