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

Communication method and apparatus

[0001] Cross-reference to Related Applications

[0002] This application claims priority to the Chinese Patent Application No. 202410725757.0, filed on June 5, 2024, and entitled “A communication method and apparatus”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of communication, and in particular to a communication method and apparatus. BACKGROUND

[0004] In recent years, the Internet of Things has attracted widespread attention in the field of wireless communication. It is expected that more “things” will be connected to each other to improve productivity efficiency and living comfort. By further reducing the size, complexity and power consumption of Internet of Things devices, hundreds or even hundreds of billions of Internet of Things devices can be deployed for various applications. Considering the cost of Internet of Things devices, the precision of the crystal oscillator used by the Internet of Things devices is poor, and the time offset of the sampling is large, that is, at each sampling time, the time considered by the sending end and the receiving end is different, which will cause the judgment of the sampling result to deviate, which will cause the receiving end to decode incorrectly. SUMMARY

[0005] Embodiments of the present application provide a communication method and apparatus for improving decoding success rate.

[0006] In a first aspect, the present application provides a communication method, which can be executed by a communication apparatus, or by other devices including the functions of the communication apparatus, or by a chip system (which can also be replaced by a chip) or other functional modules, which can realize the functions of the communication apparatus, and the chip system or functional modules are arranged in the communication apparatus, for example. The communication apparatus can be a terminal device or a reader. The method comprises: receiving a first signal; transmitting a second signal; the second signal comprises a preamble and at least one intermediate code, the first time domain length is arranged between the preamble and the first intermediate code; and / or, the second signal comprises at least two intermediate codes, and the first time domain length is arranged between the adjacent two intermediate codes; the first time domain length is determined according to the first sampling frequency deviation range, and the first sampling frequency deviation range is determined according to the first signal.

[0007] In this embodiment, the time domain length of the interval between the pilots is defined, and after receiving the second signal, the peer end can perform time offset correction according to the time domain length of the interval between the pilots detected by itself and the time domain length of the interval between the pilots agreed (i.e. the first time domain length). It can be understood that the smaller the time length of the interval between the pilots, the better the effect of time offset correction, but the larger the overhead. If the time domain length of the interval between the pilots is determined according to the maximum sampling frequency offset SFO (for example, 10 5 ppm, i.e. the deviation is 10%), the time domain length is short, the intermediate pilots are dense, and the overhead is large. In this embodiment, the time domain length is determined based on the range in which the actual SFO is located, so that the time domain length of the interval between the pilots is appropriate, which can well correct the time offset and ensure correct decoding, and will not make the pilots too dense to increase the overhead. In addition, the upper limit value, or the lower limit value, or the difference between the upper limit value and the lower limit value of the range in which the actual SFO is located is an integer, but the actual SFO may not be an integer, which will cause the calculation to be more complex when the time domain length is determined according to the actual SFO compared with when the time domain length is determined according to the range in which the actual SFO is located, that is, the calculation is simpler when the time domain length is determined according to the range in which the actual SFO is located.

[0008] In a possible implementation, the first time domain length is determined according to a first associated value of the first sampling frequency offset range, and the first associated value is an absolute value of the upper limit value or an absolute value of the lower limit value.

[0009] In a possible implementation, the first time domain length is determined according to the first associated value and a maximum time offset value deviation.

[0010] In a possible implementation, the first associated value, the maximum time offset value deviation and the first time domain length satisfy the following formula: Or Wherein, F is the time length of the minimum time unit, a is the maximum sampling time offset value, represents rounding down.

[0011] In a 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 end, and the peer end does not need to calculate the first time domain length, which can reduce the complexity of the peer end.

[0013] In a possible implementation, the third signal comprises a first preamble, and the first preamble is associated with the first time domain length; or the third signal comprises a preamble and indication information, the indication information is used to indicate the first time domain length, the indication information is located after the preamble, and a gap between the indication information and the preamble is K bits, where K is an integer greater than or equal to 0.

[0014] In a possible implementation, the first time domain length is determined according to a first sampling frequency offset (SFO) range, comprising: the first time domain length is determined according to a first difference between an upper limit value and a lower limit value of the first SFO range.

[0015] In a possible implementation, the first time domain length is determined according to the first difference, comprising: the first time domain length is determined according to the first difference and a maximum time offset value deviation.

[0016] In a possible implementation, the first difference, the maximum time offset value deviation, and the first time domain length satisfy the following formula: Or Wherein, F is a time length of a minimum time unit, a is the maximum sampling time offset value, represents rounding down.

[0017] In a possible implementation, the method further comprises: 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 end, and the peer end does not need to calculate the first time domain length, so that the complexity of the peer end can be reduced.

[0019] In a possible implementation, the second signal is sent after compensation of a sampling frequency offset according to an upper limit value or a lower limit value of the first SFO range.

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

[0021] In a possible implementation, the first time domain length is a first time domain length between the preamble and a first intermediate preamble; and / or, a first time domain length between two adjacent intermediate preambles; and the second time domain length is a second time domain length between the preamble and the first intermediate preamble; and / or, a second time domain length between two adjacent intermediate preambles; wherein the second time domain length is a third time domain length in a plurality of third time domain lengths that is less than or equal to the first time domain length and has a minimum difference with 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 third time domain length, and the first time domain length can be understood as a maximum tolerance time length of accumulated deviation. If the second time domain length exceeds the first time domain length, more deviation will be accumulated, and the decoding accuracy will be reduced.

[0023] In a 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 opposite end, and the opposite end does not need to calculate the first time domain length, so that the complexity of the opposite end can be reduced.

[0025] In a possible implementation, in a case where the second signal includes a preamble and two intermediate preambles, and a first time domain length is between the preamble and a first intermediate preamble, a second time domain length is between the first intermediate preamble and a second intermediate preamble, and the second time domain length is N times of the first time domain length, N is a positive integer greater than or equal to 1, and N is determined according to the accuracy of a supported sampling frequency offset range.

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

[0027] The time domain length of the interval between the second intermediate preamble and the first intermediate preamble can be determined based on the range in which the actual SFO is located, so that the time domain length of the interval between the preambles is appropriate, which can well correct the time offset and ensure correct decoding, and will not make the preambles too dense to increase the overhead. However, the upper limit value, or the lower limit value, or the difference between the upper limit value and the lower limit value of the range in which the actual SFO is located is an integer, but the actual SFO can not be an integer, which will lead to more complex calculation when the time domain length is determined according to the actual SFO compared with when the time domain length is determined according to the range in which the actual SFO is located. That is, it is simpler to determine the time domain length according to the range in which the actual SFO is located. Further, the difference between the upper limit value and the lower limit value of the SFO is usually fixed, which will further simplify the calculation amount compared with when the time domain length is determined by using the upper limit value or the lower limit value.

[0028] In a second aspect, a communication method is provided, which can be performed by a communication device, or by other equipment including the functions of the communication device, or by a chip system (which can also be replaced by a chip) or other functional modules, which can realize the functions of the communication device, such as being arranged in the communication device. The communication device can be a terminal device or a reader. The method comprises: transmitting or receiving a sixth signal, the sixth signal comprising a preamble and at least two intermediate preambles, the preamble and the first intermediate preamble being separated by a fourth time domain length; the first intermediate preamble and the second intermediate preamble being separated by a fifth time domain length, the fifth time domain length being N times of the fourth time domain length, N being a positive integer greater than or equal to 1, and N being determined according to the difference between the upper limit value and the lower limit value of the supported sampling frequency deviation range.

[0029] In this embodiment, the sending end considers that the receiving end will perform time offset correction (i.e. compensation) after receiving the first intermediate pilot, and receive the content after the first intermediate pilot based on the corrected time offset. After compensation, the remaining deviation is small, and the sending end can place the next intermediate pilot (i.e. the second intermediate pilot) after a longer time interval, i.e. the fifth time domain length between the second intermediate pilot and the first intermediate pilot can be greater than the fourth time domain length. The fifth time domain length can be determined based on the range in which the actual SFO is located, so that the time domain length between the pilots is appropriate, which can well correct the time offset, ensure correct decoding, and will not make the pilots too dense and increase the overhead. However, the upper limit value, or the lower limit value, or the difference between the upper limit value and the lower limit value of the range in which the actual SFO is located is an integer, but the actual SFO can not be an integer, which will cause the calculation to be more complex when the fifth time domain length is determined based on the actual SFO compared with when the fifth time domain length is determined based on the range in which the actual SFO is located. That is, the calculation is simpler when the fifth time domain length is determined based on the range in which the actual SFO is located. Further, the difference between the upper limit value and the lower limit value of the SFO is usually fixed, and the calculation amount is further simplified when the difference is used to determine the fifth time domain length compared with when the upper limit value or the lower limit value is used to determine the fifth time domain length.

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

[0031] In this example, after the fifth time domain length is determined, the fifth time domain length is still used within a short time (i.e. the first time length), which can reduce the calculation amount, and in addition, the fifth time domain length is longer than the fourth time domain length, the placement position of the intermediate pilot is more sparse, and the overhead is smaller.

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

[0033] In a possible implementation, the N is determined based on a difference between an upper limit value and a lower limit value of a supported SFO range.

[0034] In a third aspect, the present application provides a communication method, which can be performed by a communication device, or by other equipment including functions of the communication device, or by a chip system (which can also be replaced by a chip) or other functional module capable of realizing functions of the communication device, e.g., arranged in the communication device. The communication device can be a terminal device or a reader. The method comprises: transmitting or receiving an eighth signal, the eighth signal comprising intermediate pilots and / or post-pilots; and transmitting or receiving a ninth signal, the ninth signal not comprising a pre-pilot, and the ninth signal being separated from the eighth signal by a time interval less than or equal to a second time interval.

[0035] In this embodiment, after receiving the eighth signal, the second communication device can perform time offset correction according to the pilot (which can be the last pilot) comprised in the eighth signal, and in a short time (i.e., within the second time interval) after the eighth signal, synchronization can be performed without the pre-pilot, transmission of the pre-pilot is omitted, and overhead of the signal is reduced.

[0036] In a possible implementation, the time interval between the ninth signal and the eighth signal is less than or equal to the second time interval, which comprises: the time interval between the ninth signal and the last pilot in the eighth signal is less than or equal to the second time interval.

[0037] In a possible implementation, the ninth signal comprises at least one intermediate pilot, and the time interval between the first intermediate pilot and the eighth signal is less than or equal to the second time interval and / or greater than or equal to a third time interval, the third time interval being the second time interval minus a minimum time unit.

[0038] In a fourth aspect, a communication device is provided, which can be the terminal device in the above aspects. The communication device has the functions of the terminal device. The communication device can be a functional module in the terminal device, e.g., a baseband device or a chip system. Alternatively, the communication device can be the reader in the above aspects. The communication device has the functions of the reader. The communication device can be a functional module in the reader, e.g., a baseband device or a chip system.

[0039] In an alternative implementation, the communication apparatus includes a baseband device and a radio frequency device. In another alternative implementation, the communication apparatus includes a processing unit (also sometimes referred to as a processing module) and a transceiver unit (also sometimes referred to as a transceiver module). The transceiver unit is capable of implementing a transmitting function and a receiving function. When the transceiver unit implements the transmitting function, it can be referred to as a transmitting unit (also sometimes referred to as a transmitting module). When the transceiver unit implements the receiving function, it can be referred to as a receiving unit (also sometimes referred to as a receiving module). The transmitting unit and the receiving unit can be the same functional module, which is referred to as a transceiver unit, and is capable of implementing the transmitting function and the receiving function. Alternatively, the transmitting unit and the receiving unit can be different functional modules, and the transceiver unit is a general term for these functional modules.

[0040] In a possible implementation, the communication apparatus further includes a storage unit (also sometimes referred to as a storage module), and the processing unit is configured to be coupled to the storage unit and execute a program or an instruction in the storage unit, so as to enable the communication apparatus to perform the functions of the terminal device in the above aspects or perform the functions of the reader in the above aspects.

[0041] In a fifth aspect, a communication apparatus is provided, which includes an interface circuit and a processor, and optionally, a memory. The memory is configured to store a computer program, and the processor is coupled to the memory and the interface circuit. When the processor reads the computer program or the instruction, the communication apparatus performs the method performed by the terminal device in the above aspects or performs the method performed by the reader in the above aspects. For example, the interface circuit is configured to receive a signal from another communication apparatus outside the communication apparatus and transmit the signal to the processor or send a signal from the processor to another communication apparatus outside the communication apparatus, and the processor is configured to implement the method performed by the terminal device in the above aspects or implement the method performed by the reader in the above aspects by means of a logic circuit or an execution code instruction.

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

[0043] In a sixth aspect, a communication apparatus is provided, which includes a processor and optionally, a memory. The processor and the memory are coupled. The memory is configured to store a computer program or an instruction. The processor is configured to execute part or all of the computer program or the instruction in the memory. When the part or all of the computer program or the instruction is executed, the processor is configured to implement the functions of the terminal device in the above aspects or implement the functions of the reader in the above aspects.

[0044] In a possible implementation, the apparatus can further include a transceiver configured to transmit the signal processed by the processor or receive the signal input to the processor. The transceiver can perform the transmitting or receiving actions performed by the terminal device in the various aspects or performed by the reader in the various aspects.

[0045] In a 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 transceiving unit in the fourth aspect can be implemented by the transceiver.

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

[0047] In a seventh aspect, a computer readable storage medium is provided, which is configured to store a computer program or instructions, which, when executed, cause the method in the various aspects to be implemented.

[0048] In an eighth aspect, a computer program product is provided, which includes instructions, which, when executed on a computer, cause the method in the various aspects to be implemented. BRIEF DESCRIPTION OF DRAWINGS

[0049] FIG. 1a and FIG. 1b are schematic diagrams of communication system architectures provided by embodiments of the present application;

[0050] FIG. 1c is a schematic diagram of a structure of an AIoT device provided by an embodiment of the present application;

[0051] FIG. 2a and FIG. 2b are schematic diagrams of sampling deviations provided by embodiments of the present application;

[0052] FIG. 3 is a schematic diagram of a flow of a communication method provided by an embodiment of the present application;

[0053] FIG. 4a, FIG. 4b, FIG. 4c, and FIG. 4d are schematic diagrams of signal structures provided by embodiments of the present application;

[0054] FIG. 5a and FIG. 5b are schematic diagrams of detection signals provided by embodiments of the present application;

[0055] FIG. 6 is a schematic diagram of a flow of a communication method provided by an embodiment of the present application;

[0056] FIG. 7 is a schematic diagram of a flow of a communication method provided by an embodiment of the present application;

[0057] FIG. 8 is a schematic diagram of a flow of a communication method provided by an embodiment of the present application;

[0058] FIG. 9a and FIG. 9b are schematic diagrams of signal interval durations provided by embodiments of the present application;

[0059] FIG. 10 is a flow diagram of a communication method according to an embodiment of the present application;

[0060] FIG. 11 is a structural diagram of a communication apparatus according to the present application;

[0061] FIG. 12 is a structural diagram of a communication apparatus according to the present application. DETAILED DESCRIPTION

[0062] The technical solution of the present application can be applied to a terrestrial network (TN) and a non-terrestrial network (NTN), such as a satellite network. The technical solution of the present application can be applied to various wireless communication systems, such as a 4th generation (4G) system (also referred to as a long term evolution (LTE) system), a 5th generation (5G) system (also referred to as a new radio (NR) system), or a future communication system or other similar communication system, without limitation. The technical solution of the present application can also be applied to an internet of things (IoT), a passive IoT (P-IoT) or ambient IoT (A-IoT), a semi-passive IoT, a semi-active IoT, an active IoT, a narrow band IoT (NB-IoT), a machine to machine (M2M) network, machine type communication (MTC), or other network. In addition, the technical solution of the present application can be applied to a device-to-device (D2D) scenario, such as an NR-D2D scenario, or a V2X scenario, such as an NR-V2X scenario. The technical solution of the present application can also be applied to the fields of intelligent driving, assisted driving, intelligent connected vehicles, or factory manufacturing scenarios.

[0063] FIGS. 1a and 1b are structural diagrams of communication systems to which the present application is applicable. In FIG. 1a, a base station communicates directly with a terminal device. In FIG. 1b, a base station communicates with a terminal device through an intermediate node.

[0064] For the purpose of unified description, the base station in FIG. 1a and the intermediate node in FIG. 1b can be collectively referred to as a Reader, and the terminal device can be collectively referred to as a Device. The Reader sending a message to the Device can be referred to as R2D communication, and the Device sending a message to the Reader can be referred to as D2R communication. It can be understood that R2D and D2R are only names of a communication mode, and the names can be replaced by other names.

[0065] The terminal device can be a terminal device in the internet of things technology, including but not limited to a passive terminal device, a semi-passive terminal device, a semi-active terminal device, an active terminal device, a low-power terminal device, a zero-power terminal device, a passive terminal device, an active terminal device, a tag (for example, a passive tag, an active tag, a semi-active tag, a semi-passive tag), a sensor, an electricity meter, a water meter, a meter, a meter on a shared bicycle, a lock, and the like. The tag includes at least two types: one type of tag has an output power consumption of about 1 μW, has an energy storage device, and has no signal amplification capability for downlink and uplink, and can only transmit information by backscatter (that is, reflection) on an externally provided carrier wave. Another type of tag has a peak power of no more than a few hundred μW, has energy storage capability, and can amplify downlink and / or uplink signals. The tag can internally generate a signal or reflect a signal through an external carrier.

[0066] The intermediate node can be a device with wireless transceiving function, which can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; can be deployed on the water surface (such as a ship, etc.); and can be deployed in the air (such as an airplane, a balloon, and a satellite, etc.). For example, a mobile phone, a pad, a computer with wireless transceiving function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, and the like.

[0067] As shown in FIG. 1c, a structural schematic diagram of an AIoT device is introduced, the AIoT device includes 1 antenna or 2 antennas, when there are 2 antennas, one antenna is used for receiving signals or carriers, and the other antenna is used for reflecting information to be transmitted on the carrier or generating an uplink signal to send out.

[0068] When the cost of the terminal device is very low, the used crystal oscillator is not accurate, which leads to different time considered by the sending end and the receiving end, and further causes deviation of the judgment of the sampling result.

[0069] As shown in FIG. 2a, the short arrow indicates that the data of the sampling point is 0, the long arrow indicates that the data of the sampling point is 1, and the arrow indicates the data sent by the sending end. The part of 0, 1, 0, 1, 0 indicates the data sent by the sending end, and one value indicates the average value of sampling in a minimum time unit. The part of 0, 0.8, 0.2, 0.4, 0.6, 0, 0.8 indicates the data received by the receiving end, and one value indicates the average value of sampling in a minimum time unit. The sampling number corresponding to a minimum time unit is fixed, the clock of the receiving end runs slower than the clock of the sending end, and the sampling frequency of the receiving end is lower than the sampling frequency of the sending end, so that the minimum time unit detected by the receiving end is shorter than the minimum time unit used by the sending end, and the data received by the receiving end is inaccurate.

[0070] As shown in FIG. 2b, the short arrow indicates that the data of the sampling point is 0, the long arrow indicates that the data of the sampling point is 1, and the arrow indicates the data sent by the sending end. The part of 0, 1, 0, 1, 0 indicates the data sent by the sending end, and one value indicates the average value of sampling in a minimum time unit. The part of 0.1, 0.8, 0.3, 0.5, 0.8 indicates the data received by the receiving end, and one value indicates the average value of sampling in a minimum time unit. The sampling number corresponding to a minimum time unit is fixed, the clock of the receiving end runs faster than the clock of the sending end, and the sampling frequency of the receiving end is higher than the sampling frequency of the sending end, so that the minimum time unit detected by the receiving end is longer than the minimum time unit used by the sending end, and the data received by the receiving end is inaccurate.

[0071] Based on this, the embodiment of the application proposes to correct the time offset through a midamble.

[0072] In the following, some terms or concepts in the embodiments of the application are explained and described, so as to facilitate the understanding of the skilled in the art.

[0073] 1) signal, which can also be called information or message, the signal is carried on the carrier.

[0074] The signal of the present application is transmitted in the form of high and low levels, the high level can be represented by "1", and the low level can be represented by "0".

[0075] If not otherwise specified, a signal includes: a preamble, one or more data parts (for carrying data to be transmitted), one or more midambles, a postamble. Among them, the preamble is located before all midambles, and the data part is between the preamble and the first midamble; the postamble is located after all midambles, and the data part is between the last midamble and the postamble; if there are multiple midambles, the data part is also between the midambles. In the embodiments of the present application, some signals omit the preamble, which can reduce the transmission overhead of the preamble; some signals omit the midamble, which can reduce the transmission overhead of the midamble; some signals can omit the postamble, which can reduce the transmission overhead of the postamble.

[0076] The preamble, midamble and postamble are respectively a series of regular bit sequences, which are known to the sending end and the receiving end. The following introduces several examples of the preamble, wherein high represents high level, and low represents low level:

[0077] (1) high, low, high, low interleave; (2) high, low, high, high, low, low, such a rule repeats multiple times; (3) high, high, low, low, high, low, such a rule repeats multiple times; (4) high, low, low, such a rule repeats multiple times; (5) high, high, low, such a rule repeats multiple times.

[0078] The midamble and postamble can also adopt a similar structure to the preamble to obtain a sequence by interleaving high and low levels. The three kinds of codes can adopt a fixed sequence or one of multiple sequences.

[0079] The preamble is used to indicate the start of data transmission, and after the receiving end receives the preamble, it is considered that the receiving end and the sending end are approximately synchronized, i.e. the following content is the data part. After the preamble, since the sampling time offset starts to accumulate, the midamble can be used for time offset correction. The postamble is used to indicate the end of a transmission; or, the end position of a transmission can be informed by control information, without the postamble; or, when no level signal is received for a long time, it is considered that the current transmission is over.

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

[0081] The sampling time offset is caused by the sampling frequency offset (SFO), and if not otherwise specified, the sampling time offset and the SFO can be regarded as the same meaning.

[0082] For example, the sampling frequency can deviate by 10 ppm 5 ppm, the sampling frequency can deviate by 10% (i.e. 10 5 / 10 6 , where ppm means parts per million, and the unit is 10 6 ). For a device produced with a target sampling frequency of 3 MHz (i.e. 3*10 6 times per second), the actual sampling frequency is between 2.7 MHz and 3.3 MHz.

[0083] For example, the sampling frequency can deviate by 10 ppm 5 ppm, the sampling frequency can deviate by 10% (i.e. 10 5 / 10 6 , where ppm means parts per million, and the unit is 10 6 ). For a device produced with a target sampling frequency of 3 MHz (i.e. 3*10 6 times per second), the actual sampling frequency is between 2.7 MHz and 3.3 MHz.

[0084] 3) Time offset correction, i.e. sampling frequency correction:

[0085] The transmitter and the receiver know the number of samplings corresponding to a minimum time unit, and the minimum time unit can be a chip or a symbol. A chip is a unit of information after spread spectrum modulation, and can represent a length of time.

[0086] For example, one minimum time unit corresponds to p samplings, and the transmitter sends a signal with a length of 10 minimum time units. If there is no sampling time offset between the receiver and the transmitter, the receiver will receive the signal after 10*p samplings.

[0087] In an example, due to sampling time offset, the receiver receives the signal after 10*1.1p samplings, and the sampling time offset of the receiver is (1.1p-10p) / 10p=10%. The clock of the receiver runs faster than that of the transmitter, and the sampling frequency of the receiver is higher than that of the transmitter. Subsequently, when the receiver sends a signal to the transmitter, the signal is sent according to the manner of sampling 1.1p times per minimum time unit, and the other end can correctly decode; or, subsequently, when the receiver receives a signal from the transmitter, the signal is received according to the manner of sampling 1.1p times per minimum time unit, and the local end can correctly decode. The “receiver sends or receives a signal according to the manner of sampling 1.1p times per minimum time unit” can be understood as time offset correction.

[0088] In another example, due to the sampling time offset, the receiving end receives the signals after sampling 10*0.95p times, and the sampling time offset of the receiving end is (0.95p-10p) / 10p=-5%. The clock of the receiving end runs slower than the clock of the sending end, and the sampling frequency of the receiving end is lower than the sampling frequency of the sending end. Subsequently, when the receiving end sends signals to the sending end, the receiving end sends the signals in a manner of sampling 0.95p times per minimum time unit, and the peer end can correctly decode; or, subsequently, when the receiving end receives signals from the sending end, the receiving end receives the signals in a manner of sampling 0.95p times per minimum time unit, and the receiving end can correctly decode. The "receiving end sends or receives signals in a manner of sampling 0.95p times per minimum time unit" herein can be understood as time offset correction.

[0089] 4) The method provided by each of the embodiments of the present application can be applied to the network architecture shown in FIG. 1a or FIG. 1b or other network architectures. For example, the first communication apparatus involved in each of the embodiments of the present application is the terminal device in FIG. 1a, and the second communication apparatus is the base station (which can also be referred to as a reader) in FIG. 1a; or the second communication apparatus is the terminal device in FIG. 1a, and the first communication apparatus is the base station in FIG. 1a. For example, the first communication apparatus involved in each of the embodiments of the present application is the terminal device in FIG. 1b, and the second communication apparatus is the intermediate node (which can also be referred to as a reader) in FIG. 1b; or the second communication apparatus is the terminal device in FIG. 1b, and the first communication apparatus is the intermediate node in FIG. 1b.

[0090] The present application introduces a plurality of embodiments, each of which can be used as an embodiment alone or in combination with two or more embodiments without logical errors.

[0091] In order to better introduce the embodiments of the present application, the method provided by the embodiments of the present application can be introduced in combination with the accompanying drawings. In the accompanying drawings corresponding to each of the embodiments of the present application, the steps represented by the dashed lines are optional steps. The method provided by the embodiments of the present application can be executed by a communication apparatus, or by other devices including the functions of the communication apparatus, or by a chip system (which can also be replaced by a chip) or other functional modules, which can realize the functions of the communication apparatus, for example, are arranged in the communication apparatus. When the execution subject is the above-mentioned chip system or other functional modules, the receiving / sending can be understood as input / output, for example, the above-mentioned chip system or other functional modules communicate with other functional modules or components of the communication apparatus. In addition, the processing executed by a single execution subject can also be divided into processing executed by multiple execution subjects, which can be logically and / or physically separated.

[0092] Embodiment one:

[0093] FIG. 3 is a flow diagram of a communication method according to an embodiment of the present 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 carrying data. The form of the first signal is not limited, as long as the second communication device can determine the sampling frequency offset 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] The second signal includes a preamble and at least one intermediate preamble, and the first time domain length is between the preamble and the first intermediate preamble; and / or, the second signal includes at least two intermediate preambles, and the first time domain length is between any two adjacent intermediate preambles.

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

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

[0100] In another example, the second signal includes at least two intermediate preambles, and the first time domain length is between any two adjacent intermediate preambles. The second signal can include a preamble or not include a preamble. If the second signal includes a preamble, the time length 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 FIG. 4b, and the first time domain length is between the preamble and the first intermediate preamble, and the first time domain length is between the first intermediate preamble and the second intermediate preamble. Further optionally, the first time domain length is between any two adjacent intermediate preambles.

[0102] In another example, the second signal comprises a preamble and at least two intermediate codes, a first time domain length is between the preamble and the first intermediate code, N times of the first time domain length is between the first intermediate code and the second intermediate code, N is a positive integer greater than or equal to 1, and N is determined according to a difference between an upper limit value and a lower limit value of a sampling frequency offset range supported by the first communication device and / or the second communication device. As shown in FIG. 4c, M chips (i.e., the first time domain length) are between the preamble and the first intermediate code, and M*N chips (i.e., the second time domain length) are between the first intermediate code and the second intermediate code.

[0103] Based on the above-mentioned various structures of the second signal, further optionally, the second signal further comprises a postamble, the postamble is located at the end of the second signal, and the preamble and the intermediate codes are all located before the postamble.

[0104] It can be understood that the data to be transmitted is between the preamble and the intermediate codes, between the intermediate codes, and between the last intermediate code and the postamble.

[0105] The first time domain length is determined according to a first sampling frequency offset range, and the first sampling frequency offset range is determined according to 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, the first communication device performs time offset correction / sampling frequency correction based on a number of samplings between the preamble and the first intermediate code in the second signal based on the first time domain length, and / or based on a number of samplings between the first intermediate code and the second intermediate code in the second signal. After the time offset correction / sampling frequency correction, the data after the first intermediate code in the second signal can be decoded, a signal can be sent to the second communication device, or a signal can be received from the second communication device.

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

[0109] In an example, due to sampling time offset or SFO, the first communication device samples 10*1.05*p times between the preamble and the first midamble in the second signal, and the sampling time offset or SFO is (10*1.05*p-10p) / 10p=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 the sampling frequency 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 sample at the new sampling frequency to decode data after the first midamble in the second signal, and the decoding accuracy of the data after the first midamble can be improved.

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

[0111] In an example, due to sampling time offset or SFO, the first communication device samples 10*0.95*p times between the preamble and the first midamble in the second signal, and the sampling time offset 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 the sampling frequency of the second communication device. The first communication device can determine a new sampling frequency, which is 95% of the original sampling frequency. The first communication device samples at the new sampling frequency to decode data after the first midamble in the second signal, and the accuracy of the data after the first midamble can be improved.

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

[0113] In this embodiment, the time domain length of the interval between the preambles is defined, and after receiving the second signal, the receiving end can perform time offset correction according to the time domain length of the interval between the preambles detected by itself and the time domain length of the interval between the preambles agreed upon. It can be understood that the smaller the time length of the interval between the preambles, the better the effect of time offset correction, but the larger the overhead.

[0114] If the maximum SFO (e.g., 10 5The time domain length of the interval between the pilots is determined according to the first time domain length, and the time domain length of the interval between the pilots is shorter, the pilots are denser, and the overhead is larger. For example, the maximum time offset is a us, the minimum time unit (for example, one chip) is 2a us, one minimum time unit introduces a sampling time offset of 0.2a us at most, and 5 minimum time units are placed for one pilot, and the time domain length of the interval between the pilots is 5 minimum time units, for example, 5 chips.

[0115] In this embodiment, the first time domain length involved in the second signal of step 302 is determined according to the first sampling frequency offset range, and the first sampling frequency offset range is determined according to the first signal. That is, the first time domain length is determined based on the range in which the actual SFO is located. The time domain length is determined based on the range in which the actual SFO is located, so that the time domain length of the interval between the pilots is more appropriate, which can well correct the time offset and ensure correct decoding, and will not make the pilots too dense and increase the overhead.

[0116] In addition, the upper limit value of the range in which the actual SFO is located, or the lower limit value, or the difference between the upper limit value and the lower limit value is an integer, but the actual SFO may not be an integer, which will cause the time domain length to be determined according to the actual SFO, and the calculation is more complex compared with the time domain length determined according to the range in which the actual SFO is located, that is, the calculation is simpler when the time domain length is determined according to the range in which the actual SFO is located.

[0117] Optionally, after step 301 and before step 302, 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. The following describes an example in which the second communication device determines the first SFO range based on the first signal:

[0118] The second communication device can determine the range in which the SFO is located, that is, the first SFO range, according to the first signal.

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

[0120] As shown in FIG. 5a, a schematic diagram of Manchester encoding is introduced. Manchester will have a transition at the middle position corresponding to each bit, for example, from high to low, indicating “1”, from low to high, indicating “0”, and for example, from high to low, indicating “0”, from low to high, indicating “1”.

[0121] For example, the first communication device transmits signals in a manner that each chip occupies p sampling time length, in the Machester code mode, there is a rising edge or a falling edge in the middle of each chip, and the second communication device can identify the potential range of the first SFO according to the interval between the rising edge or the falling edge in the middle of the two consecutive chips. For example, the second communication device collects 1.05p sampling points from the middle of the first chip to the middle of the second chip, and the sampling time offset between the first communication device and the second communication device is (1.05p-p) / p=5%. After the second communication device determines the sampling time offset, it can generate the length of a single chip in the transmission signal according to 1.05p, thereby reducing the sampling time offset with the first communication device.

[0122] As shown in FIG. 5b, a schematic diagram of PIE is introduced. When the duration of high level and low level is the same, the position of high-low level transition (i.e. the position of falling edge) represents "0", and when the duration of high level is 3 times of the duration of low level, the position of high-low level transition (i.e. the position of falling edge) represents "1".

[0123] For example, the first communication device transmits signals in a manner that each chip occupies p sampling time length, in the PIE code mode, whether the data is 0 or 1, there is a low level, i.e. a rising edge after the low level of the next time unit. The second communication device receives the interval between a falling edge and the next rising edge, which is 0.9p sampling points, so that the sampling time offset can be calculated as (0.9p-p) / p=-10%. After the second communication device determines the sampling time offset, it can generate the length of a single chip in the transmission signal according to 0.9p, thereby reducing the sampling time offset with the first communication device.

[0124] The upper limit value and the lower limit value of the range of the first SFO can or can not be included in the range, for example, the range of the first SFO is [s1, s2] or (s1, s2] or (s1, s2), where s1

[0125] The second communication device supports one or more SFO ranges with accuracy, where the accuracy refers to the difference between the upper limit value and the lower limit value of the SFO range. One accuracy corresponds to one set of SFO ranges, and one set of SFO ranges includes multiple consecutive SFO ranges. For example, the accuracy is 10 4 ppm, and one 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, a set of SFO ranges with a precision of 5*10 3 ppm, -9.5*10 5 ppm), [-9.5 4 ppm, -9*10 5 ppm), [0, 5*10 4 ppm], (5*10 3 ppm, 10 3 ppm], …, (9.5*10 4 ppm, 10 4 ppm] these SFO ranges. For example, a first SFO range is (10 5 ppm, 2*10 4 ppm], or (9.5*10 4 ppm, 10 4 ppm] The positive or negative of the SFO range value indicates whether the sampling frequency of the local end is higher or lower than that of the peer end. 5

[0126] The manner in which the second communication device determines the first time domain length based on the first SFO range includes but is not limited to the following two manners:

[0127] The following describes the first manner:

[0128] The second communication device or a third party device stores the association between the associated value (the upper limit value, or the absolute value of the upper limit value, or the lower limit value, or the absolute value of the lower limit value) of the SFO range and the time domain length, which can be embodied in the form of a table, or in the form of a formula, or in other forms. After determining the first SFO range, the second communication device can determine the time domain length associated with the first associated value of the first SFO, i.e., the first time domain length, based on the first associated value. The second communication device can calculate the first time domain length based on the first associated value by using the following formula, or the second communication device can find the first time domain length by looking up the table based on the first associated value.

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

[0130] wherein:

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

[0132] K represents a maximum time offset that can be tolerated in a proportion of a minimum time unit, K is any value between 0 and 1. In an optional example, K is determined according to the maximum time offset value a, for example,

[0133] F is the length of the minimum time unit. For example, the minimum time unit is a chip or a symbol. For example, a chip is 66.67us, 71.4us, 35.7us, etc. For example, at 15kHz, a symbol length is 66.67us, and at 30kHz, a symbol length is 33.33us. In addition, a chip can be a symbol or a fraction of a symbol, for example, at 15kHz, a symbol length is 66.67us, and a chip can be 33.33us, 16.67us, etc. Optionally, the length of the minimum time unit is related to the maximum SFO value (for example, 5%, 10%). For example, the maximum SFO value is 10 5 ppm, i.e., the deviation is 10%.

[0134] When , it can be seen that: the first time domain length can be determined according to the first associated value of the first SFO range and the maximum time offset value a.

[0135] In a possible example, the first time domain length, the first associated value of the first SFO range, and the maximum time offset value a satisfy the following formula 2 (i.e., substituting into formula 1 to obtain formula 2):

[0136] In a possible example, the first time domain length is M minimum time units, i.e. , then M and the first associated value of the first SFO range satisfy the following formula 3:

[0137] When , M, the first associated value of the first SFO range, and the maximum time offset value satisfy the following formula 4 (i.e., substituting into formula 3 to obtain formula 4):

[0138] In the case of W = 10 6 , the minimum time unit is a chip, and a chip is 66.67us, based on formula 4, the following formula 5 can be obtained:

[0139] It should be noted that the first correlation value in the above formulas 1-5 can be positive, or 0, but not negative. For example, the first SFO range is (3*10 4 ppm, 4*10 4 ppm], the first correlation value can be the lower limit value 3*10 4 , or the upper limit value 4*10 4 . For another example, the first SFO range is (-4*10 4 ppm, -3*10 4 ppm], the first correlation value can be the absolute value of the upper limit value 3*10 4 , or the absolute value of the lower limit value 4*10 4 , the first correlation value is neither the upper limit value -3*10 4 , nor the lower limit value -4*10 4 .

[0140] In a possible example, the first correlation value is the larger one of the absolute value of the upper limit value and the absolute value of the lower limit value. When the SFO is larger, the pilot placement is denser, and the time domain length of the interval between pilots is shorter. Based on the above formulas, it can also be seen that this is the case. The larger the first correlation value is, the shorter the determined first time domain length is, and the better the effect of correcting the time offset is. Therefore, the time domain length determined by the larger SFO value in the range can correct the time offset caused by the larger SFO, and can also correct the time offset caused by the smaller SFO. The time domain length determined by the smaller SFO value in the range is longer, and the correction effect for the time offset caused by the larger SFO is not good, and the decoding accuracy will be reduced. Although the overhead can be reduced, the decoding accuracy is more important than the overhead. Therefore, by setting the first correlation value to be the larger one of the absolute value of the upper limit value and the absolute value of the lower limit value, the time offset can be well corrected, the decoding accuracy can be ensured, and the overhead will not be too large. Compared with determining the time domain length by using the largest SFO, the decoding accuracy can be ensured, and the overhead is reduced.

[0141] In a possible implementation, the above formulas 1-5 are modified in the following multiple ways:

[0142] For example, the content on the right side of the “equal to” in the above formulas 1-5 is taken as a whole, which can be rounded up or rounded down, so that the first time domain length is an integer multiple of the minimum time unit. For example, formula 5 can be modified as: wherein, represents rounding down. Other formulas are also modified in a similar way, which will not be described in detail.

[0143] For example, the first SFO range is [10 4 ppm, 2*10 4 ppm], the upper limit value (i.e. the first correlation value) 2*10 4 is brought into formula 5, we can get: When a = 33.33us, about 25, M = 25, i.e. 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 value (i.e. the first correlation value) 4*10 4 is brought into formula 5, we can get: When a = 33.33us, about 12.5, M = 12, i.e. 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], the upper limit value (i.e. the first correlation value) 5.5*10 4 is brought into formula 5, we can get: When a = 33.33us, about 9.01, M = 9, i.e. the first time domain length is 9 chips.

[0146] For example, the content on the right side of the "equal to" in the above formulas 1-5 is regarded as a whole and is rounded, and then multiplied by a coefficient. The rounding can be upward rounding or downward rounding.

[0147] For example, the content on the right side of the "equal to" in the above formulas 1-5 is regarded as a whole and is multiplied by a coefficient, and then rounded. The rounding can be upward rounding or downward rounding.

[0148] For example, the content on the right side of the "equal to" in the above formulas 1-5 is regarded as a whole and is multiplied by a coefficient.

[0149] For example, the content on the right side of the "equal to" in the above formulas 1-5 is regarded as a whole and is rounded, and then multiplied by a coefficient. The rounding can be upward rounding or downward rounding. The rest remains unchanged, and the rounding can be upward rounding or downward rounding. Optionally, the rounded value can be divisible by 2, i.e. the rounded value is a multiple of 2. In this way, the first time domain length can be an integer multiple of the minimum time unit.

[0150] The application should ensure that the value of M is an integer, so that the first time domain unit is the entire minimum time unit. In addition, the value of the coefficient mentioned above can be between 0 and 1, so that there is still enough useful signal in the case of decoding deviation.

[0151] In a possible example, the placement position of the intermediate pilot is the start position of the symbol, that is, the first time domain length between the preamble and the intermediate pilot, or the interval between two adjacent intermediate pilots, is an integer number of symbols, for example, N symbols, N is an integer greater than or equal to 1. If the minimum time unit F used to determine M is one chip (that is, F in the above formulas 1-5 and various modified formulas is one chip), the unit of M is chhip, one symbol can carry A chips, where A is greater than 1, then That is, the lower limit of M / A is taken. The first time domain length between the preamble and the intermediate pilot is M' chips, where M' = N*A. For example, M = 10, A = 4, then N = 2, M' = 8.

[0152] In another possibility, the end position of the preamble or the previous intermediate pilot is not the end position of a symbol. For example, the end position of the preamble or the previous intermediate pilot is the A'th chip in a symbol, so there are still A-A' chips available in the symbol, so that M' = N*A+A-A ′ = (N+1)*A-A', which reduces the value of M so that the start position of the next intermediate pilot is at the beginning of the symbol.

[0153] The following describes a way 2 of determining the first time domain length based on the first SFO range (that is, the first time domain length is determined according to the first difference between the upper limit value and the lower limit value of the first SFO range).

[0154] The difference between the upper limit value and the lower limit value of the SFO range and the time domain length can be saved in the second communication device or the third party equipment, and the association relationship can be embodied in the form of a table, or in the form of a formula, or in other forms. After determining the first SFO range, the second communication device can determine the time domain length associated with the first difference based on the first difference between the upper limit value and the lower limit value of the first SFO, that is, the first time domain length. The second communication device can calculate the first time domain length based on the first difference by the following formula, or the second communication device can find the first time domain length by looking up the table based on the first difference.

[0155] In a possible example, the first time domain length and the first difference of the first SFO range satisfy the following formula 6:

[0156] The related description of W, K, and F can refer to the description in formula 1, which will not be repeated here.

[0157] When , it can be seen that the first time domain length can be determined according to the first difference of the first SFO range and the maximum time offset value a.

[0158] In a possible example, the first time domain length, the first difference of the first SFO range, and the maximum time offset value satisfy the following formula 7 (that is, substituting into formula 6 to obtain formula 7):

[0159] In a possible example, the first time domain length is M minimum time units, that is, Then M, the first difference of the first SFO range, satisfy the following formula 8:

[0160] When , M, the first difference of the first SFO range, and the maximum time offset value satisfy the following formula 9 (that is, substituting into formula 8 to obtain formula 9):

[0161] In the case of W=10 6 , the minimum time unit is one chip, and one chip is 66.67us. Based on formula 9, the following formula 10 can be obtained:

[0162] In a possible implementation, the above formulas 6-10 are modified in the following multiple ways:

[0163] For example, the content on the right side of the “equal sign =” in the above formulas 6-10 is taken as a whole, which can be rounded up or rounded down, so that the first time domain length is an integer multiple of the minimum time unit. For example, formula 10 can be transformed as: Where, represents rounding down. Other formulas are also similarly transformed and will not be repeated in detail.

[0164] For example, the first difference of the first SFO range is 10 4 ppm, and the first difference 10 4 is brought into formula 10, which can obtain: When a=33.33us, is about 50, and M=50, that is, the first time domain length is 50 chips.

[0165] For example, the first difference of the first SFO range is 5*10 3 ppm, the first difference 5*10 3 Substitute the formula 10, we can get: When a = 33.33us, about 100, M = 100, and the first time domain length is 100 chips.

[0166] For example, take the content on the right side of the "equal to" in the above formulas 6-10 as a whole to round, and then multiply a coefficient. The rounding can be upward rounding or downward rounding.

[0167] For example, multiply the content on the right side of the "equal to" in the above formulas 6-10 as a whole by a coefficient, and then round. The rounding can be upward rounding or downward rounding.

[0168] For example, multiply the content on the right side of the "equal to" in the above formulas 6-10 as a whole by a coefficient.

[0169] For example, take the content on the right side of the "equal to" in the above formulas 6-10 as a whole to round, round, and the rest remains unchanged. The rounding can be upward rounding or downward rounding. Optionally, the rounded value can be divisible by 2, that is, the rounded value is a multiple of 2, so as to ensure that the first time domain length is an integer multiple of the minimum time unit.

[0170] The present application should ensure that the value of M is an integer, so as to ensure that the first time domain unit is the entire minimum time unit. In addition, the value of the coefficient mentioned above can be between 0 and 1, so as to ensure that there is still enough useful signal in the case of decoding deviation.

[0171] In one possible example, the placement position of the middle pilot is the start position of the symbol, that is, the first time domain length between the preamble and the middle pilot, or the interval between two adjacent middle pilots, is an integer number of symbols, for example, N symbols, N being an integer greater than or equal to 1. If the minimum time unit F used to determine M is one chip (that is, F in the above formulas 6-10 and various modified formulas is one chip), the unit of M is chhip, one symbol can carry A chips, where A is greater than 1, and that is, round down M / A. Then the first time domain length between the preamble and the middle pilot is M' chips, where M' = N*A. For example, M = 22, A = 4, then N = 5, M' = 20.

[0172] In another possibility, the position of the end of the preamble or the previous intermediate preamble is not the end of a symbol, for example, the position of the end of the preamble or the previous intermediate preamble is the A'th chip in a symbol, so there are still A-A' chips available in the symbol, so that M' = N*A + A - A' ′ = (N + 1) * A - A', which example reduces the value of M so that the start position of the next intermediate preamble is at the beginning of a symbol.

[0173] The second communication device can determine the first time domain length in the above-mentioned manner 1 or manner 2, and for the first communication device, the first time domain length also needs to be known, so that time offset correction can be performed.

[0174] The following introduces various examples of the first communication device knowing the first time domain length (the serial numbers in the following examples are only for convenience of description, and do not represent the good and bad and priority of the examples):

[0175] Example 1.1: After the second communication device determines the first time domain length in the manner 1 or manner 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 of the second communication device sending the third signal to the first communication device and step 302 (the second device sending the second signal to the first device) is not limited.

[0177] The following introduces various examples of the third signal indicating the first time domain length:

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

[0179] When the first communication device and the second communication device communicate, there are various preambles allowed to be used. The embodiments of the present application stipulate that one preamble is associated with one 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), and the first communication device and the second communication device can both save the association relationship between the preamble and the time domain length.

[0180] For example, there are 4 kinds of allowed preambles, which are preambles 0-3, and the time domain lengths corresponding to the preambles 0-3 are 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 carries the preamble 2 in the third signal. After receiving the third signal, the first communication device can detect that the preamble carried by the third signal is the preamble 2, and the first communication device can determine that the time domain length corresponding to the preamble 2 is 15 chips, and thus knows that the interval between the preamble and the first intermediate preamble in the second signal of step 302 is 15 chips, and / or the interval between the first intermediate preamble and the second intermediate preamble in the second signal is 15 chips.

[0181] In an example, the third signal includes a preamble and indication information, the indication information is used to indicate the first time domain length, the indication information is located after the preamble, and the indication information and the preamble are separated by K bits, where K is an integer greater than or equal to 0. The indication information can occupy one or more bits.

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

[0183] Example 1.2: The second communication device determines the first time domain length in mode 1, and the second communication device can indicate the first SFO range or the first correlation value to the first communication device, and the first communication device calculates the first time domain length in the same way as the second communication device. The way in which the second communication device indicates the first SFO range or the first correlation value to the first communication device is similar to the way in which the third signal indicates the first time domain length, and will not be described in detail.

[0184] Example 1.3: The second communication device determines the first time domain length in mode 2, and the second communication device can inform the first communication device of the first difference value of the first SFO. For example, the second communication device sends a fourth signal, and correspondingly, the first communication device receives the fourth signal, where the fourth signal is used to indicate the first difference value. For example, the fourth signal includes a second preamble, and the second preamble is associated with the first difference value. For another example, the fourth signal includes a preamble and indication information, the indication information is used to indicate the first difference value, the indication information is located after the preamble, and the indication information and the preamble are separated by K bits, where K is an integer greater than or equal to 0. The way in which the fourth signal indicates the first difference value is similar to the way in which the third signal indicates the first time domain length, and can be referred to each other, and will not be repeated.

[0185] The second communication device indicates the first SFO range or the first correlation value or the first difference value to the first communication device without limitation on the order of steps 302 (the second device sends the second signal to the first device).

[0186] In addition, if the second communication device has limited capability and only supports one precision of SFO (i.e., the difference between the upper limit value and the lower limit value of SFO), the second communication device can inform the first communication device of its capability (i.e., the supported precision of SFO), which is equivalent to informing the first communication device of the first difference value. For example, if there are two precisions of SFO, the second communication device can indicate one of the two precisions by 1 bit. Alternatively, the capability of the communication device is set to two, for example, high and low, for example, the SFO precision corresponding to the high capability is 5*10 3 ppm, and the SFO precision corresponding to the low capability is 10 4 ppm, the second communication device can indicate the capability of the second communication device by 1 bit, for example, 0 bit represents low capability, i.e., SFO precision is 10 4 ppm; 1 bit represents high capability, i.e., SFO precision is 5*10 3 ppm.

[0187] Example 1.4: The first communication device is pre-configured with the first time domain length, and 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 mode 2.

[0188] The embodiments of the present application provide mode 1 and mode 2 for determining the first time domain length, and the second communication device can be pre-configured to determine the first time domain length by mode 1 or mode 2. For example, all communication devices are configured to determine the first time domain length by mode 1, or all communication devices are configured to determine the first time domain length by mode 2. For another example, based on the capability of the communication device, the communication device is configured to determine the first time domain length by mode 1 or mode 2. For example, when the communication device supports compensating the sampling frequency deviation according to the upper limit value or the lower limit value of the sampling frequency deviation range, the communication device can be configured to determine the first time domain length by mode 2, and if the communication device does not support compensating the sampling frequency deviation according to the upper limit value or the lower limit value of the sampling frequency deviation range, the communication device can be configured to determine the first time domain length by mode 1. Further optionally, the second communication device indicates to the first communication device to determine the first time domain length by mode 1 or mode 2.

[0189] In a possible implementation, the second communication device or a third party can pre-store a plurality of third time domain lengths, and after the first communication device determines the first time domain length based on the first SFO range, the second communication device can select a suitable time domain length from the plurality of third time domain lengths based on the first time domain length as the final time domain length. For the convenience 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 code in the second signal in step 302 is the first time domain length; and / or, the interval between two adjacent intermediate codes is the first time domain length, which can be replaced by: the interval between the preamble and the first intermediate code in the second signal is the second time domain length; and / or, the interval between two adjacent intermediate codes is the second time domain length. The second time domain length is: a third time domain length that is less than or equal to the first time domain length and has the minimum difference with the first time domain length from the pre-stored plurality of third time domain lengths.

[0191] Optionally, the plurality of pre-stored third time domain lengths are equally spaced.

[0192] For example, the plurality of pre-stored third time domain lengths include 5 chips, 10 chips, 15 chips, and 20 chips, and the first time domain length determined based on the first SFO range is 14 chips. In the plurality of third time domain lengths, the one that is closest to the first time domain length and less than the first time domain length is 10 chips, and thus 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-stored third time domain length. The first time domain length can be understood as the maximum tolerance time length of accumulated deviation. If the second time domain length exceeds the first time domain length, more deviation will be accumulated, which will reduce the decoding accuracy.

[0194] If the interval between the preamble and the first intermediate code in the second signal is the second time domain length; and / or, the interval between two adjacent intermediate codes is the second time domain length, the first communication device also needs to know the second time domain length to perform the time offset correction / sampling frequency correction.

[0195] The following describes a plurality of examples in which the first communication device knows the second time domain length (the serial numbers in the following examples are only for the convenience of description, and do not represent the good or bad and 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 the first communication device receives the fifth signal. The fifth signal is used to indicate the second time domain length. For example, the fifth signal includes a third preamble, and the third preamble is associated with the second time domain length. For another example, the fifth signal includes a preamble and indication information, the indication information is used to indicate the second time domain length, the indication information is located after the preamble, and the indication information is separated from the preamble by K bits, where K is an integer greater than or equal to 0. The fifth signal indicates the second time domain length in a similar manner to the third signal indicating the first time domain length, and the two manners can be referred to each other, which will not be described here. In this example, the values or the number of the third time domain lengths are limited, and compared with the first time domain length, the second communication device can more easily indicate the second time domain length to the first communication device, and the overhead of the indication can be saved.

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

[0198] Example 2.3: The second communication device determines the first time domain length based on the manner 1, and indicates the first SFO range or the first association value to the first communication device. The first communication device stores a plurality of third time domain lengths, and after the first communication device determines the first time domain length in the same manner as the second communication device, the first communication device selects a suitable third time domain length from the plurality of third time domain lengths based on the first time domain length in the same manner as the second communication device, and the suitable third time domain length is the second time domain length.

[0199] Example 2.4: The second communication device determines the first time domain length based on the manner 2, and indicates the first difference value of the first SFO range to the first communication device. The first communication device stores a plurality of third time domain lengths, and after the first communication device determines the first time domain length in the same manner as the second communication device, the first communication device selects a suitable third time domain length from the plurality of third time domain lengths based on the first time domain length in the same manner as the first communication device, and the suitable third time domain length is the second time domain length.

[0200] The second communication device indicates the second time domain length, or the first time domain length, or the first SFO range, or the first association value, or the first difference value to the first communication device in any order with respect to the step 302 (the second device sends the second signal to the first device).

[0201] In combination with FIG. 3 and the second time domain length, a flowchart of a communication method is shown in FIG. 6.

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

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

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

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

[0206] Step 605: The second communication device sends a second signal, and the first communication device receives the second signal accordingly, where the second signal includes a preamble and at least one intermediate preamble, and the preamble and the first intermediate preamble are separated by the second time domain length; and / or the second signal includes at least two intermediate preambles, and adjacent two intermediate preambles are separated by the second time domain length.

[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 number of times of sampling between the preamble and the first intermediate preamble in the second signal based on the second time domain length, and / or the first communication device performs time offset correction / sampling frequency correction based on the number of times of sampling between the first preamble and the second intermediate preamble in the second signal. The process of step 606 is similar to that of step 303, where the first communication device performs time offset correction / sampling frequency correction based on the first time domain length, and thus is not repeated here.

[0209] In a possible implementation, the first time domain length is determined based on the manner 2 (i.e., the first time domain length is determined based on the first difference between the upper limit value and the lower limit value of the first SFO range), and in step 302, the second communication apparatus can compensate for the SFO when transmitting the second signal, i.e., the second signal in step 302 is transmitted after compensating for the sampling frequency offset according to the upper limit value or the lower limit value of the first sampling frequency offset range. After the second communication apparatus compensates for the SFO between the second communication apparatus and the first communication apparatus, the remaining SFO is within the allowed maximum deviation range, for example, [-c, c] or [0, c], where c is the accuracy. After the compensation, the second signal can be transmitted with a first time domain length between the preamble of the second signal and the first intermediate preamble; and / or, a second time domain length between the preamble of the second signal and the first intermediate preamble in a scenario where the interval between adjacent two intermediate preambles is the first time domain length.

[0210] For example, the first communication apparatus transmits X chips (e.g., the first signal in step 301 occupies X chips), each chip lasts for a duration corresponding to N sampling points as considered by the first communication apparatus, and the second communication apparatus receives the chips using 1.052*X*N sampling points. The second communication apparatus can identify that the SFO range is [5x10 4 ppm, 6x10 4 ppm], and the second communication apparatus can compensate according to the absolute value of the upper limit value or the absolute value of the lower limit value of the range, i.e., the second communication apparatus transmits the second signal with a duration corresponding to 1.05N or 1.06N sampling points as the duration of a chip, i.e., the compensation is performed, so that the remaining deviation should not exceed 10 4 ppm.

[0211] For another example, the first communication apparatus transmits X chips (e.g., the first signal in step 301 occupies X chips), each chip lasts for a duration corresponding to N sampling points as considered by the first communication apparatus, and the second communication apparatus receives the chips using 0.932*X*N sampling points. The second communication apparatus can identify that the SFO range is [-7x10 4 ppm, -6x10 4 ppm], and the second communication apparatus can compensate according to the absolute value of the upper limit value or the absolute value of the lower limit value of the range, i.e., the second communication apparatus transmits the second signal with a duration corresponding to 0.93N or 0.94N sampling points as the duration of a chip, i.e., the compensation is performed, so that the remaining deviation should not exceed 10 4 ppm.

[0212] Embodiment two:

[0213] As shown in Figure 7, a flowchart of a communication method is introduced.

[0214] Step 701: The first communication device sends a sixth signal, which includes: a preamble and at least two intermediate codes, the preamble and the first intermediate code are separated by a fourth time domain length; the first intermediate code and the second intermediate code are separated by a fifth time domain length, the fifth time domain length is N times of the fourth time domain length, N is a positive integer greater than or equal to 1, and N is determined according to the difference between the upper limit value and the lower limit value of the supported sampling frequency deviation range.

[0215] As shown in Figure 4c, the preamble and the first intermediate code are separated by M chips (i.e. the fourth time domain length), and the first intermediate code and the second intermediate code are separated by M*N chips (i.e. the fifth time domain length).

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

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

[0218] After compensating for SFO, the remaining SFO is within the allowed maximum 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 times of sampling between the preamble and the first intermediate code in the sixth signal, which is similar to the content introduced in step 303 and will not be described in detail.

[0220] Further optionally, step 703: After receiving the second intermediate code in the sixth signal, the second communication device performs time offset correction (i.e. compensates for SFO again based on the compensation in step 702) based on the second intermediate code in the sixth signal and the fifth time domain length, and receives the content after the second intermediate code based on the corrected time offset (i.e. 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 times of sampling between the first intermediate code and the second intermediate code in the sixth signal, which is similar to the content introduced in step 303 and will not be described in detail.

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

[0223] The fifth time domain length can be determined based on the range in which the actual SFO is located, so that the time domain length between the pilots is appropriate, which can well correct the time offset and ensure correct decoding, and will not make the pilots too dense and increase the overhead. However, the upper limit value, or the lower limit value, or the difference between the upper limit value and the lower limit value of the range in which the actual SFO is located is an integer, but the actual SFO can not be an integer, which will lead to more complex calculation when determining the fifth time domain length according to the actual SFO compared with determining the fifth time domain length according to the range in which the actual SFO is located. That is, it is simpler to determine the fifth time domain length according to the range in which the actual SFO is located. Further, the difference between the upper limit value and the lower limit value of the SFO is usually fixed, which will further simplify the calculation amount compared with determining the fifth time domain length using the upper limit value or the lower limit value.

[0224] The first communication device and the second communication device can both determine the fourth time domain length, and the following describes various examples of determining the fourth time domain length: In one example, the fourth time domain length is determined in the same way as the first time domain length or the second time domain length described in Embodiment 1. That is, the fourth time domain length can be regarded as the first time domain length or the 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, i.e., the maximum deviation is 10%, for example, the maximum time offset is a us, the minimum time unit (e.g., one chip) is 2a us, one minimum time unit introduces a sampling time offset of 0.2a us at most, and 5 minimum time units place 1 intermediate pilot, i.e., the fourth time length is 5 minimum time units, e.g., 5 chips.

[0225] The first communication device and the second communication device can both determine the multiple N, and the following describes various examples of determining the multiple N:

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

[0227] As shown in FIG. 4d, the interval between the preamble and the first midamble is 5 chips, and the interval between the first midamble and the second midamble is 50 chips.

[0228] In another example, as described above, the maximum SFO (e.g. 10 5 ppm) is fixed, and the accuracy of the supported SFO range is also known, so the value of N is fixed and can be preconfigured or set by factory.

[0229] In one possible example, the first communication device sends the sixth signal. After detecting the first midamble, the second communication device can determine the range of the SFO according to the fourth time domain length of the interval between the first midamble and the preamble. For example, according to the time length occupied by the first midamble sequence, the maximum range of the correction can be obtained, and according to the time length occupied by the first midamble sequence or the number of chips of the interval between the first midamble and the preamble, the accuracy range can be obtained. Alternatively, the accuracy of the SFO range is preconfigured in the second communication device and the first communication device, so no calculation is needed.

[0230] If the sixth signal includes at least three midambles, the interval between the second midamble and the third midamble can be a fifth time domain length (e.g. M*N chips), or a time domain length longer or shorter than the fifth time domain length, for example, according to the measurement accuracy of a period of time before the second midamble (i.e. the difference between the upper limit value and the lower limit value of the SFO range that can be reached by measurement), or the accuracy of the supported SFO range, to further determine the time domain length of the interval between the third midamble and the second midamble, which is not limited in the embodiments of the present application.

[0231] In one possible implementation, the first communication device and the second communication device can save the fifth time domain length for a period of time, and in the "new transmission" of the period of time, the interval between the preamble and the first midamble can be the fifth time domain length, and / or the interval between two adjacent midambles can also be the fifth time domain length.

[0232] For example, after the sixth signal, the first communication device sends a seventh signal, and the second communication device receives the seventh signal accordingly; or the second communication device sends the seventh signal, and the first communication device receives the seventh signal. The interval between the seventh signal and the sixth signal is less than or equal to the first time length. For example, the first time length is one day or one week, etc. The seventh signal includes a preamble and at least one intermediate preamble, and the interval between the preamble and the first intermediate preamble is the fifth time length. Further, the interval between two adjacent intermediate preambles in the seventh signal is the fifth time length. After determining the fifth time length, the fifth time length is still used in a shorter time (i.e., the first time length), which can reduce the calculation amount. In addition, the fifth time length is longer than the fourth time length, the placement position of the intermediate preamble is more sparse, and the overhead is smaller.

[0233] The interval between the seventh signal and the sixth signal has the following cases: The sixth signal can be the starting position or the ending position of the last preamble (which can be an intermediate preamble or a postamble) in the sixth signal, the ending position of the sixth signal, a position in the sixth signal that is spaced apart from the ending position by a preset distance (which is before the ending position and can be applicable to the scenario that the sixth signal does not include a postamble), the starting position of the sixth signal, or a position in the sixth signal that is spaced apart from the starting position by a preset distance (which is after the starting position). The seventh signal can be the starting position or the ending position of the first preamble in the seventh signal, the starting position of the seventh signal, a position in the seventh signal that is spaced apart from the starting position by a preset distance (which is after the starting position), the ending position of the seventh signal, or a position in the seventh signal that is spaced apart from the ending position by a preset distance (which is before the ending position and can be applicable to the scenario that the seventh signal does not include a postamble). In a specific example, the interval between the ending position of the last preamble in the sixth signal and the starting position of the first preamble in the seventh signal is less than or equal to the second time length.

[0234] In a possible example, a second time length is set, for example, the second time length is multiple of the fifth time domain length, and the second time length is much smaller than the first time length. The second time length can be understood as a maximum tolerable time length that can be correctly decoded in the process of time offset accumulation. That is, when the time offset accumulation is too large after the second time length, the probability of decoding error increases. If the time length between the seventh signal and the sixth signal after the sixth signal is less than or equal to the second time length, the seventh signal can not include the preamble and include at least one intermediate preamble. For example, the start of the seventh signal is the first intermediate preamble, or the start of the seventh signal is a data part, and the first intermediate preamble is after a period of time. In this example, the second communication device can perform time offset correction according to the last preamble in the sixth signal after receiving the sixth signal, and can not need the preamble for synchronization in a short time (that is, within the second time length) after the sixth signal, so that the transmission of the preamble is omitted, and the overhead of the signal can be reduced.

[0235] Embodiment three:

[0236] As shown in FIG. 8, a flowchart of a communication method is introduced.

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

[0238] The eighth signal includes an intermediate preamble and / or a postamble. On this basis, further optionally, the eighth signal further includes a preamble.

[0239] Optionally, step 802: The second communication device performs time offset correction based on the preamble (for example, the intermediate preamble and / or the postamble) included in the eighth signal.

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

[0241] Step 803a: The first communication device sends a 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] Step 803a and step 803b can be executed one of them.

[0244] The ninth signal does not include a preamble, and the time length between the ninth signal and the eighth signal is less than or equal to the second time length. The second time length can be understood as a maximum tolerable time length that can be correctly decoded in the process of time offset accumulation. That is, when the time offset accumulation is too large after the second time length, the probability of decoding error increases.

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

[0246] The time interval between the eighth signal and the ninth signal can be as follows: the eighth signal can be specifically: the starting position or the ending position of the last code (the last code can be a middle code or a post code) in the eighth signal, or the ending position of the eighth signal, or a position in the eighth signal that is spaced apart from the ending position by a preset distance (the position is before the ending position, which can be applicable to a scenario in which the eighth signal does not include a post code), the starting position of the eighth signal, or a position in the eighth signal that is spaced apart from the starting position by a preset distance (the position is after the starting position). The ninth signal can be specifically: the starting position or the ending position of the first code in the ninth signal, or the starting position of the eighth signal, or a position in the ninth signal that is spaced apart from the starting position by a preset distance (the position is after the starting position), or the ending position of the ninth signal, or a position in the ninth signal that is spaced apart from the ending position by a preset distance (the position is before the ending position, which can be applicable to a scenario in which the ninth signal does not include a post code). In one specific example, the time interval between the ending position of the last code in the eighth signal and the starting position of the first code in the ninth signal is less than or equal to the second time length.

[0247] When the second embodiment and the third embodiment are combined, the second time length is multiple times the fifth time domain length, and the second time length is much smaller than the first time length. The eighth signal can be regarded as the sixth signal in the second embodiment, and the ninth signal can be regarded as the seventh signal in the second embodiment.

[0248] As shown in FIG. 9a, three possible cases are introduced: case 1: the time interval between the ending position of the eighth signal and the ending position of the ninth signal is less than the second time length, and the ninth signal can not include any code (for example, a preamble, a middle code, or a post code). Case 2: the time interval between the ending position of the eighth signal and the starting position of the ninth signal is less than the second time length, the time interval between the ending position of the eighth signal and the ending position of the ninth signal is greater than the second time length, the ninth signal does not include a preamble and includes at least one middle code. Case 3: the time interval between the ending position of the eighth signal and the starting position of the ninth signal is greater than the second time length, and the starting 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 according to the code (which can be the last code) included in the eighth signal, and within a short time (i.e., within the second time length) after the eighth signal, a preamble can not be needed for synchronization, transmission of the preamble can be omitted, and the overhead of the signal can be reduced.

[0250] In a possible example, the ninth signal does not include a preamble, and includes at least one midamble, i.e., the beginning of the ninth signal is a data part, and a midamble follows a period of time (i.e., case 2 in FIG. 7). The ninth signal includes a first midamble, and the time interval between the first midamble and the eighth signal is less than or equal to the second time length, and / or, the time interval between the first midamble and the eighth signal is greater than or equal to a third time length, the third time length being the second time length minus a minimum time unit. The minimum time unit can be one chip or one symbol.

[0251] The time interval between the first midamble and the eighth signal has the following cases: the eighth signal here can be specifically: the starting position or the ending position of the last midamble (which can be a midamble or a postamble) in the eighth signal, or the ending position of the eighth signal, or a position in the eighth signal that is spaced apart from the ending position by a preset distance (the position is before the ending position, which can be applicable to a scenario in which the eighth signal does not include a postamble). The first midamble here can be specifically: the starting position or the ending position of the first midamble.

[0252] As shown in FIG. 9b, the last midamble in the eighth signal is a postamble, the beginning of the ninth signal is a data part, the data part is followed by a first midamble, and the time interval between the ending position of the postamble in the eighth signal and the first midamble in the ninth signal is less than the second time length and greater than the third time length.

[0253] The second time length can be understood as the maximum tolerable time length that can be decoded correctly in the process of accumulating the time offset, that is, when the second time length is exceeded, the accumulated time offset is too large, and the probability of decoding error increases. Therefore, the midamble is placed at the latest within the second time length, and the time interval between the first midamble in the ninth signal and the eighth signal is less than the second time length. Within the second time length, the later the position of the midamble, the smaller the overhead of the signal.

[0254] In actual transmission, the transmission interval between the eighth signal and the ninth signal can be an integer multiple of the minimum time unit, or a non-integer multiple of the minimum time unit, for example, 2.5 minimum time units, 6 minimum time units, etc. The length a is set as the transmission interval between the eighth signal and the ninth signal, the length a includes v minimum time units, for example, v is 2.5 or 6, and the sum of the length a and one minimum time unit is less than the second length. Assuming that the second length includes G minimum time units, in the second length, the ninth signal can occupy G-v minimum time units. It can be understood that any signal is transmitted in the length of the minimum time unit, that is, the first midamble in the ninth signal is placed at the start position of a minimum time unit in the ninth signal.

[0255] If v is a non-integer, if the midamble is placed at the start position of the minimum time unit in the ninth signal, the interval between the start position of the midamble and the end position of the eighth signal is greater than the second length, which can cause the accumulated deviation to be too large, so the midamble is placed at the start position of the minimum time unit in the ninth signal. Wherein, is the floor function, is the ceiling function.

[0256] Embodiment four:

[0257] In step 303 of embodiment one, it is introduced that after the first communication device receives the second signal, the time offset correction / sampling frequency correction can be performed based on the first time domain length. For example, after the time offset correction / sampling frequency correction, the first communication device can decode the data after the first midamble in the second signal, or send a signal to the second communication device, or receive a signal from the second communication device. However, how to correct the time offset between the preamble and the first midamble is not introduced in detail. Based on this, embodiment four introduces how to correct the time offset of the data received before based on the midamble or the postamble in any signal.

[0258] As shown in FIG. 2a, the clock of the receiving end runs slower than the clock of the sending end, and the sampling frequency of the receiving end is lower than the sampling frequency of the sending end, so the minimum time unit detected by the receiving end is shorter than the minimum time unit used by the sending end.

[0259] It is set that in the i-th minimum time unit, the data sent by the sending end is x i , without considering noise and SFO, and the data received by the receiving end in the i-th minimum time unit is x i .

[0260] It is assumed that the SFO is -10 5ppm, i.e. 10% deviation forward (in time), then the data received by the receiving end in the first minimum time unit is 0.9x1, in the second minimum time unit is 0.1x1+0.8x2, in the third minimum time unit is 0.2x2+0.7x3, and so on.

[0261] On this basis, the noise in the ith minimum time unit is set as n i Then the data y i received by the receiving end in the ith time unit is: 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 ; corresponding to the tenth minimum time unit.

[0262] As shown in FIG. 2b, the clock of the receiving end runs faster than that of the sending end, and the sampling frequency of the receiving end is higher than that of the sending end, so that a minimum time unit detected by the receiving end is longer than a minimum time unit adopted by the sending end.

[0263] It is assumed that the data sent by the sending end in the ith minimum time unit is x i , without considering noise and without SFO, and the data received by the receiving end in the ith minimum time unit is x i .

[0264] It is assumed that the SFO is +10 5 ppm, i.e. 10% deviation forward (in time), then the data received by the receiving end in the first minimum time unit is x1+0.1x2, in the second minimum time unit is 0.9x2+0.2x3, in the third minimum time unit is 0.8x3+0.3x4, and so on.

[0265] On this basis, the noise in the ith minimum time unit is set as n i Then the data y ix1+0.1x2+n1=y1; (corresponding to a minimum time unit) 0.9x2+0.2x3+n2=y2; (corresponding to a second minimum 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 a tenth minimum time unit).

[0266] It is assumed that the communication device knows the preamble and the intermediate preamble, or the interval H between the preamble and the postamble, H is an integer greater than 1, the minimum time unit can be one chip or one symbol; the noise is very small and has little effect on the data.

[0267] As shown in FIG. 10, a flowchart of a communication method is introduced.

[0268] Step 101: The communication device receives the preamble for synchronization, and after synchronization, determines the sampling result in each minimum time unit according to the sampling points (for example, the data y i in the above formula).

[0269] The sampling points refer to a plurality of points collected in one minimum time unit based on the sampling frequency, and each minimum time unit includes a very large number of sampling points. If the storage capacity of the communication device is limited, the communication device will not store each sampling point, but can store the sampling result in each minimum time unit.

[0270] Step 102: After H minimum time units, the communication device synchronizes according to the intermediate preamble or the postamble, and obtains the accumulated time offset in the time interval between the preamble and the preamble.

[0271] Step 103: The communication device divides the accumulated time offset to R minimum time units according to the accumulated time offset to correct the sampling result, and R is an integer greater than or equal to 1.

[0272] If a midamble or postamble is expected to be received in the Rth smallest time unit, due to the sampling time offset of the receiving end, the receiving end samples the R+1th smallest time unit, and detects the midamble or postamble in the R-1th smallest time unit and the R+1th smallest time unit. The signal waveform of the midamble or postamble in the R-1th or R+1th smallest time unit needs to be stored (for example, stored in the receiver), and based on the sampling result of the remaining midamble or postamble, the signal strength of the midamble or postamble is calculated, and then the sampling result of the last smallest time unit is derived.

[0273] It can be understood that, in order to implement the functions in the above embodiments, the first communication device and the second communication device include corresponding hardware structures and / or software modules for performing the functions. Those skilled in the art should easily understand that, in combination with the units and method steps of the examples described in the embodiments disclosed in the present application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in hardware or computer software driven hardware depends on the specific application scenario and design constraints of the technical solution.

[0274] FIGS. 11 and 12 are structural schematic diagrams of possible communication devices provided by the embodiments of the present application. These communication devices can be used to implement the functions of the first communication device or the 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 FIG. 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 (for example, the first communication device or the second communication device) in the above method embodiments shown in FIGS. 3, 6, 7, 8 and 10. The transceiver unit 1120 can perform the receiving actions and the sending actions performed by the communication device in the above method embodiments. The processing unit 1110 can perform the actions performed by the communication device in the above method embodiments, except for the sending actions and the receiving actions.

[0277] For example, when the communication device 1100 is used to implement the functions of the second communication device in the method embodiment shown in FIG. 3, the transceiver unit 1120 is used to receive the first signal and send the second signal. The processing unit 1110 is used to analyze the first signal, generate the second signal, determine the first SFO range based on the first signal, and determine the first time domain length based on the first SFO range.

[0278] More details of the processing unit 1110 and the transceiver unit 1120 can be found in the description of the method embodiments shown in FIG. 3, FIG. 6, FIG. 7, FIG. 8 and FIG. 10, which are not 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 FIG. 12, the communication apparatus 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are coupled to each other. It can be understood that the interface circuit 1220 can be a transceiver or an input / output interface. Optionally, the communication apparatus 1200 can further include a memory 1230, which is used to store instructions executed by the processor 1210, or to store input data required by the processor 1210 to execute instructions, or to store data generated after the processor 1210 executes instructions. Sometimes, the interface circuit 1220 can also be understood as a part of the processor 1210, and at this time, the communication apparatus 1200 includes the processor 1210.

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

[0281] When the above communication apparatus 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 that the information is first received by other modules (such as a radio frequency module or an antenna) in the terminal device, and then sent to the terminal device chip by these modules. The terminal device chip sends information to the network device, which can be understood as that the information is first sent to other modules (such as a radio frequency module or an antenna) in the terminal device, and then sent to the network device by these modules.

[0282] When the above communication apparatus 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 a terminal device, which can be understood as that the information is first received by other modules (such as a radio frequency module or an antenna) 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 that the information is first sent to other modules (such as a radio frequency module or an antenna) in the network device, and then sent to the terminal device by these modules. The network device module here can be a baseband chip of the network device, or a DU or other module, and the DU here can be a DU under the open radio access network (O-RAN) architecture.

[0283] In the present application, the sending of information from entity A to entity B can be direct sending from A to B or indirect sending from A to B via other entities. Similarly, the receiving of information from entity A by entity B can be direct receiving of the information sent by entity A or indirect receiving of the information sent by entity A via other entities. The entity A and the entity B can be network devices or terminal devices, or modules in a network device or a terminal device. The sending and receiving of information can be information interaction between a network device and a terminal device, or information interaction between two network devices, such as information interaction between a CU and a DU, or information interaction between different modules in one device, such as information interaction between a terminal device chip and other modules in the terminal device, or information interaction between a network device chip and other modules in the network device.

[0284] It can be understood that the processor in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0285] The embodiments of the present application further provide a computer readable storage medium, which stores a computer program. When the computer program is executed by a computer, the computer can be used to execute the communication method described above. In other words, the computer program includes instructions for implementing the communication.

[0286] The embodiments of the present application further provide a computer program product, which includes computer program code. When the computer program code is run on a computer, the computer can execute the communication method provided above.

[0287] The embodiments of the present application further provide a communication system, which includes a first communication device and a second communication device for executing the communication method described above.

[0288] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk, a mobile hard disk, a compact disc read-only memory (CD-ROM) (also known as a read-only optical disc), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. Of course, the processor and the storage medium can also exist as discrete components in the base station or the terminal.

[0289] In the above embodiments, the implementation can be entirely or partially by software, hardware, firmware, or any combination thereof. When implemented by software, the implementation can be entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When loaded and executed on a computer, the computer programs or instructions perform the processes or functions described in the embodiments of the present application 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, user equipment, or other programmable devices. The computer programs or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another, for example, the computer programs or instructions can be transferred from one website, computer, server, or data center to another by wired or wireless means. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center, etc. that integrates one or more available media. The available media can be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape; an optical medium, such as a digital video disc; or a semiconductor medium, such as a solid-state disk. The computer-readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile storage media.

[0290] In various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be mutually referred to if there is no special description and no logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0291] In the embodiments of the present application, the number of nouns, unless otherwise specified, represents "a singular noun or a plural noun", i.e. "one or more". "At least one" refers to one or more, and "multiple" refers to two or more. "And / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone, wherein A or B can be singular or plural. The character " / " generally represents that the associated objects before and after it are in an "or" relationship. For example, A / B represents A or B. "At least one of the following" or "one or more of the following" and the like refer to any combination of these items, including any combination of single item or multiple items. For example, at least one of a, b and (or) c, or one or more of a, b and (or) c, represents 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 "first", "second", etc. mentioned in the embodiments of the present application are used to distinguish a plurality of objects, and are not used to limit the size, content, order, time sequence, priority or importance of the plurality of objects. Moreover, such names also do not represent the difference in the content, sending / receiving end, sending order, size, application scenario, priority or importance of the two pieces of information. In addition, the numbering of steps in each embodiment introduced in the present application is only for distinguishing different steps, and is not used to limit the order between the steps.

Claims

1. A communication method characterized by comprising: Comprising: receiving a first signal; sending a second signal; the second signal comprising a preamble and at least one intermediate code, a first time domain length being spaced between the preamble and the first intermediate code; and / or, the second signal comprising at least two intermediate codes, a first time domain length being spaced between two adjacent intermediate codes; the first time domain length being determined according to a first sampling frequency offset range, the first sampling frequency offset range being determined according to the first signal.

2. The method of claim 1, wherein, The first time domain length is determined according to a first sampling frequency offset range, comprising: The first time domain length is determined according to a first associated value of the first sampling frequency offset range, the first associated value being an absolute value of an upper limit value or an absolute value of a lower limit value.

3. The method of claim 2, wherein, The first time domain length is determined according to a first associated value of the first sampling frequency offset range, comprising: The first time domain length is determined according to the first associated value and a maximum sampling time offset value.

4. The method of claim 3, wherein, The first time domain length comprises M minimum time units; The first associated value, the maximum sampling time offset value and the M satisfy the following formula: or Wherein, F is the time length of the minimum time unit, a is the maximum sampling time offset value, Indicates rounding down.

5. The method according to any one of claims 2 to 4, wherein, Further comprising: sending a third signal, the third signal being used to indicate the first time domain length.

6. The method of claim 5, wherein, The third signal comprises a first preamble, the first preamble being associated with the first time domain length; or, The third signal comprises a preamble and indication information, the indication information being used to indicate the first time domain length, the indication information being located after the preamble, a K-bit interval being spaced between the indication information and the preamble, the K being an integer greater than or equal to 0.

7. The method of claim 1, wherein, The first time domain length is determined according to a first sampling frequency offset range, comprising: The first time domain length is determined according to a first difference value between an upper limit value and a lower limit value of the first sampling frequency offset range.

8. The method of claim 7, wherein, The first time domain length is determined according to the first difference value, comprising: The first time domain length is determined according to the first difference value and a maximum sampling time offset value.

9. The method of claim 8, wherein, The first time domain length comprises M minimum time units; The first difference value, the maximum sampling time offset value and the M satisfy the following formula: or wherein F is the duration of a minimum time unit, a is the maximum sampling time offset value, Indicates rounding down.

10. The method according to any one of claims 7 to 9, characterized in that, Further comprising: sending a fourth signal, the fourth signal being used to indicate the first difference value or the first time domain length.

11. The method according to any one of claims 7 to 10, wherein, The second signal is sent after compensating for the sampling frequency offset according to the upper limit value or the lower limit value of the first sampling frequency offset range.

12. The method of any one of claims 1-4, 6-9, and 11, wherein, The first time domain length is spaced between the preamble and the first intermediate code; and / or, the first time domain length is spaced between two adjacent intermediate codes, comprising: The second time domain length is spaced between the preamble and the first intermediate code; and / or, the second time domain length is spaced between two adjacent intermediate codes; wherein, the second time domain length is: a third time domain length smaller than or equal to the first time domain length and having the smallest difference value with the first time domain length in a plurality of third time domain lengths pre-stored.

13. The method of claim 12, wherein, Further comprising: sending a fifth signal, the fifth signal being used to indicate the second time domain length.

14. The method of any one of claims 1-13, wherein, In a case that the second signal comprises a preamble and two intermediate preambles, the first intermediate preamble and the second intermediate preamble are separated by a first time domain length, and the second intermediate preamble and the preamble are separated by N times of the first time domain length, N is a positive integer greater than or equal to 1, and N is determined according to the accuracy of the supported sampling frequency offset range.

15. A method of communication, comprising: Comprise: transmitting or receiving a sixth signal, the sixth signal comprising a preamble and at least two intermediate preambles, the preamble and the first intermediate preamble being separated by a fourth time domain length; the first intermediate preamble and the second intermediate preamble being separated by a fifth time domain length, the fifth time domain length being N times of the fourth time domain length, N being a positive integer greater than or equal to 1, and N being determined according to the difference between the upper limit value and the lower limit value of the supported sampling frequency offset range.

16. The method of claim 15, wherein, Further comprise: transmitting 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 separated 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 interval.

17. The method of claim 15 or 16, wherein, The fourth time domain length is determined based on the maximum sampling frequency offset value.

18. The method of any one of claims 15-17, wherein, N is determined according to the difference between the upper limit value and the lower limit value of the supported SFO range.

19. A method of communication, comprising: Comprise: transmitting or receiving an eighth signal, the eighth signal comprising an intermediate preamble and / or a postamble; transmitting or receiving a ninth signal, the ninth signal not comprising a preamble, and the time interval between the ninth signal and the eighth signal being less than or equal to a second time interval.

20. The method of claim 19, wherein, The time interval between the ninth signal and the eighth signal is less than or equal to a second time interval, comprising: 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.

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

22. A communications device, characterized by Comprise a module for performing the method of any one of claims 1-21.

23. A communications device, characterized by Comprise a processor coupled with a memory; The memory is configured to store computer programs or instructions; The processor is configured 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 method of any one of claims 1-21.

24. A communications device, characterized by Comprise a processor and a memory; The memory is configured to store computer programs or instructions; The processor is configured 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 method of any one of claims 1-21.

25. A computer-readable storage medium, characterized in that, The storage medium stores computer programs or instructions, and when the computer programs or instructions are executed by a communication device, the method of any one of claims 1-21 is implemented.

26. A computer program product, characterised in that, The computer program product comprises computer instructions which, when run on a computer, cause the method of any one of claims 1-21 to be implemented.

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