A chirp communication method

Abstract

The invention discloses a chirp communication method, which belongs to the field of communication technology. The generated chirp signal is packaged using a large SF and small bandwidth package method, and then the packaged chirp data is received and frequency offset compensated. Finally, the frequency offset compensated chirp data is sent to a demodulation module to splice to obtain a data packet, thereby completing the communication process. The method solves the technical problems in the prior art that high-sensitivity chirp communication can only be performed under ideal conditions, the framing overhead is too large, and the delay result and the frequency offset result cannot be effectively compensated.

Description

Technical Field

[0001] The invention belongs to the field of communication technology, and in particular relates to a chirp communication method. Background Art

[0002] In wireless communications, chirp waveforms are a spread spectrum technology that can achieve high sensitivity because the occupied bandwidth is much larger than the signal. In addition, the signal is widely used in various radar and communication scenarios because of its strong anti-multipath capability, low transmission energy and long transmission distance.

[0003] When chirp signals are used for communication, a larger spreading factor and smaller bandwidth can achieve higher sensitivity, but the time required to transmit the same data is longer. For example, when SF=6 and BW=500KHz, the length of a symbol is 0.12 milliseconds, but when SF=12 and BW=7.8125KHz, the transmission time of a symbol is 0.5s (seconds).

[0004] In the communication system, when the information transmitted is large and a large SF (such as SF=12) and a small bandwidth (such as BW=7.8125KHz) are used, the non-ideal characteristics of the actual hardware (such as temperature changes, long-term jitter, external interference, etc.) cause the frequency deviation and other non-ideal characteristics in a packet of data to change, which ultimately leads to abnormal frequency deviation compensation and received data errors. This situation not only causes the communication function to be impaired, but also causes the sensitivity of the communication system to fail to reach the high sensitivity index. Therefore, a real-time communication method for large SF and small bandwidth is needed to ensure the high sensitivity of the entire communication system. Summary of the invention

[0005] In view of the problem of reduced system sensitivity in communication transmission in the prior art, the present invention proposes a CHIRP communication method, the purpose of which is to improve the sensitivity of chirp communication under non-ideal conditions and reduce the overhead of framing.

[0006] To achieve the above purpose, the present invention adopts the following technical approach: providing a chirp communication method,

[0007] Step 1: Generate chirp signal;

[0008] Step 2: Pack the generated chirp signal using a large SF and small bandwidth packetization method;

[0009] Step 3: Receive the chirp data after packetization and compensate for the frequency deviation;

[0010] Step 4: Send the chirp data after frequency offset compensation to the demodulation module to splice the data packet to complete the communication.

[0011] Preferably, the specific process of generating the chirp signal in the first step is as follows:

[0012] First, a modulated chirp symbol is generated according to the signal bandwidth BW, the spreading factor SF, the modulated bit information, etc. Represents the length of time for a symbol

[0013] Then the modulated signal It is expressed as:

[0014]

[0015]

[0016] in Equal to 1 or -1, when =1 represents upchirp signal, when =-1 represents a downchirp signal, K represents the modulated bit information, t represents time, j represents the imaginary unit, and B represents bandwidth.

[0017] Preferably, the chirp signal is packaged as follows in the second step:

[0018] First, generate The number of preambles is generated according to the upchirp method. =1, K=0;

[0019] Then generate The number of downchirp signals, =-1, K=0, , Represents a configurable length; then the header data and the payload data (PL) data are grouped into one symbol per SF, and the corresponding signal is generated according to the chirp generation method in the first step; if the header data and the payload data (PL) data cannot be divided by SF, then they are rounded up.

[0020] Preferably, the header data and the payload data are split into groups of L bits each. When the sum of the header data and the payload data is P bits, the header data and the payload data are divided into G groups: ;

[0021] Where ceil represents rounding up. If it is not an integer, then add a number of 0 bits after P until P is an integer multiple of L. The number of 0 bits Z added is expressed as: .

[0022] Preferably, the first packaging method of the G groups of data is as follows: the first group of preambles, the first group of downchirps, the first group of headers, the first group of payload data, the second group of preambles, the second group of downchirps, the second group of headers, the second group of payload data, ... the Gth group of preambles, the Gth group of downchirps, the Gth group of headers, the Gth group of payload data;

[0023] The second packaging method of G groups of data is as follows: preamble, first group of downchirps, first group of headers, first group of payload data, second group of downchirps, second group of headers, second group of payload data, Gth group of downchirps, Gth group of headers, Gth group of payload data.

[0024] Preferably, if the first packet grouping method is used, the third step is as follows: Let the estimated delay result of the gth group be , the frequency deviation result of the g-th group estimation is , where 1≤ ≤G, and then perform delay compensation and frequency deviation compensation.

[0025] Preferably, frequency offset compensation includes the following methods:

[0026] Method 1: and The estimated result of is used to compensate the header data and the payload data of the g-th group;

[0027] Method 2: Set the data from group 1 to group g Find the average and convert the data from group 1 to group g into Taking the average, we get:

[0028] , ,

[0029] and will as well as Compensate to the header data and payload data of the g-th group;

[0030] Method 3: Set the data from group 1 to group g Find the average value and convert the data from group 1 to group g into Taking the average, we get:

[0031] , ,

[0032] and will as well as Compensate into the header data and payload data of each group;

[0033] Method 4: First calculate the weight of each set of data:

[0034] , ,

[0035] in Represents the average value of G package sto, Represents the standard deviation of the g-th package sto;

[0036] The weight of sto for group g is ,

[0037] The final calculated It is expressed as follows:

[0038] ;

[0039] Calculate the mean and standard deviation of cfo:

[0040]

[0041]

[0042] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0043] The cfo weight of group g is ;

[0044] The final calculated It is expressed as follows:

[0045] ,

[0046] and will as well as Compensate to the header and payload data of group g;

[0047] Method 5: First calculate the weight of each set of data:

[0048]

[0049]

[0050] in Represents the average value of G package sto, Represents the standard deviation of the sto value of the gth package;

[0051] The sto weight of group g is ;

[0052] The final calculated It is expressed as follows:

[0053]

[0054] Calculate the mean and standard deviation of cfo:

[0055]

[0056]

[0057] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0058] The cfo weight of group g is ;

[0059] The final calculated It is expressed as follows:

[0060] ,

[0061] and will as well as Compensate to the header data and payload data of the g-th group;

[0062] Method 6: The weights obtained by arbitrarily combining the scattered results of methods 4 and 5 are used as the STO and CFO values ​​for compensation.

[0063] Preferably, if the second packaging method is used, the third step is as follows: Let the frequency deviation result of the g-th group estimation be , where 1≤ ≤G.

[0064] Better, get the g group The methods for calculating the final CFO compensation value include the following:

[0065] Method A: The estimated result is used to compensate the header data and the payload data of the g-th group;

[0066] Method B: Set the data from group 1 to group g Taking the average, we get:

[0067] , and Compensate to the header data and payload data of the g-th group;

[0068] Method C: Set the data from group 1 to group g Taking the average, we get:

[0069] ,

[0070] and will Compensate into the header data and payload data of each group;

[0071] Method D: Calculate the mean and standard deviation of CFO:

[0072]

[0073]

[0074] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0075] The cfo weight of group g is ;

[0076] The final calculated It is expressed as follows:

[0077] ,

[0078] and will Compensate to the header and payload data of group g;

[0079] Method E: Calculate the mean and standard deviation of CFO:

[0080]

[0081]

[0082] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0083] The cfo weight of group g is ;

[0084] The final calculated It is expressed as follows:

[0085] ,

[0086] and will Compensate to the header data and payload data of group g.

[0087] Preferably, the first group of header data to the Gth group of header data after frequency offset compensation are averaged and then demodulated to obtain the header bit data;

[0088] Then, the first group of payload data to the Gth group of payload data are demodulated respectively, and finally the demodulated data are spliced ​​in sequence to obtain the received data packet, thus completing the communication process.

[0089] Compared with the prior art, the technical approach of the present invention has the following advantages / benefits:

[0090] 1. By and The estimation result is compensated to the header data and payload data of the g-th group, thereby improving the timeliness of compensation and the sensitivity of communication.

[0091] 2. Packetize 1-G groups of payload data in the following manner: the first group of preambles, the first group of downchirps, the first group of headers, the first group of payload data, the second group of preambles, the second group of downchirps, the second group of headers, the second group of payload data, ... the Gth group of preambles, the Gth group of downchirps, the Gth group of headers, the Gth group of payload data; reduce the amount of computation for packetization, reduce the requirements for hardware facilities, and improve the stability of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] In order to more clearly illustrate the technical methods of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0093] Figure 1 It is a flow chart of a chirp communication method of the present invention. DETAILED DESCRIPTION

[0094] In order to make the purpose, technical methods and advantages of the present invention clearer, the technical methods in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0095] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it may not be further defined or explained in the subsequent drawings.

[0096] Embodiment 1:

[0097] like Figure 1 As shown, a chirp communication method comprises the following steps:

[0098] Step 1: Generate chirp signal;

[0099] Step 2: Pack the generated chirp signal using a large SF and small bandwidth packetization method;

[0100] Step 3: Receive the chirp data after packetization and compensate for the frequency deviation;

[0101] Step 4: Send the chirp data after frequency offset compensation to the demodulation module to splice the data packet to complete the communication.

[0102] Preferably, the specific process of generating the chirp signal in the first step is as follows:

[0103] First, a modulated chirp symbol is generated according to the signal bandwidth BW, the spreading factor SF, the modulated bit information, etc. Represents the length of time for a symbol

[0104] Then the modulated signal It is expressed as:

[0105]

[0106]

[0107] in Equal to 1 or -1, when =1 represents upchirp signal, when =-1 represents a downchirp signal, K represents the modulated bit information, t represents time, j represents the imaginary unit, and B represents bandwidth.

[0108] The chirp signal is packaged as follows in the second step:

[0109] First, generate The number of preambles is generated according to the upchirp method. =1, K=0;

[0110] Then generate The number of downchirp signals, =-1, K=0, , Represents a configurable length; then the header data and the payload data (PL) data are combined into one symbol per SF, and the corresponding signal is generated according to the above chirp generation method; if the header data and the payload data (PL) data cannot be divided by SF, then they are rounded up.

[0111] The header data and the payload data are split into groups of L bits each. When the sum of the header data and the payload data is P bits, the header data and the payload data are divided into G groups: ;

[0112] Where ceil represents rounding up. If it is not an integer, then add a number of 0 bits after P until P is an integer multiple of L. The number of 0 bits Z added is expressed as: .

[0113] The G groups of data are packaged as follows: the first group of preambles, the first group of downchirps, the first group of headers, the first group of payload data, the second group of preambles, the second group of downchirps, the second group of headers, the second group of payload data, ... the Gth group of preambles, the Gth group of downchirps, the Gth group of headers, the Gth group of payload data;

[0114] The third step is as follows: Let the estimated delay result of group g be , the frequency deviation result of the g-th group estimation is , where 1≤ ≤G, and then perform delay compensation and frequency deviation compensation.

[0115] Frequency offset compensation includes the following methods:

[0116] Method 1: and The estimated result is used to compensate the header data and payload data of the g-th group, thereby improving the timeliness of the compensation.

[0117] Method 2: Set the data from group 1 to group g Find the average and convert the data from group 1 to group g into Taking the average, we get:

[0118] , ,

[0119] and will as well as The compensation is added to the header data and payload data of the g-th group, which improves the stability of the compensation process.

[0120] Method 3: Set the data from group 1 to group g Find the average value and convert the data from group 1 to group g into Taking the average, we get:

[0121] , ,

[0122] and will as well as The compensation is added to the header data and payload data of each group to further improve the stability of the compensation process.

[0123] Method 4: First calculate the weight of each set of data:

[0124] , ,

[0125] in Represents the average value of G package sto, Represents the standard deviation of the g-th package sto;

[0126] The weight of sto for group g is ,

[0127] The final calculated It is expressed as follows:

[0128] ;

[0129] Calculate the mean and standard deviation of cfo:

[0130]

[0131]

[0132] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0133] The cfo weight of group g is ;

[0134] The final calculated It is expressed as follows:

[0135] ,

[0136] and will as well as The compensation is added to the header and payload data of the g-th group, thereby achieving better communication performance and enhancing communication stability.

[0137] Method 5: First calculate the weight of each set of data:

[0138]

[0139]

[0140] in Represents the average value of G package sto, Represents the standard deviation of the sto value of the gth package;

[0141] The sto weight of group g is ;

[0142] The final calculated It is expressed as follows:

[0143]

[0144] Calculate the mean and standard deviation of cfo:

[0145]

[0146]

[0147] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0148] The cfo weight of group g is ;

[0149] The final calculated It is expressed as follows:

[0150] ,

[0151] and will as well as Compensate to the header data and payload data of the g-th group;

[0152] Method 6: The weights obtained by arbitrarily combining the scattered results of methods 4 and 5 are used as the STO and CFO values ​​for compensation.

[0153] The first group of header data to the Gth group of header data after frequency offset compensation are averaged and then demodulated to obtain the header bit data;

[0154] Then, the first group of payload data to the Gth group of payload data are demodulated respectively, and finally the demodulated data are spliced ​​in sequence to obtain the received data packet, thus completing the communication process.

[0155] Example 2: Figure 1 As shown, a CHIRP communication method comprises the following steps:

[0156] Step 1: Generate chirp signal;

[0157] Step 2: Pack the generated chirp signal using a large SF and small bandwidth packetization method;

[0158] Step 3: Receive the chirp data after packetization and compensate for the frequency deviation;

[0159] Step 4: Send the chirp data after frequency offset compensation to the demodulation module to splice the data packet to complete the communication.

[0160] Preferably, the specific process of generating the chirp signal in the first step is as follows:

[0161] First, a modulated chirp symbol is generated according to the signal bandwidth BW, the spreading factor SF, the modulated bit information, etc. Represents the length of time for a symbol

[0162] Then the modulated signal It is expressed as:

[0163]

[0164]

[0165] in Equal to 1 or -1, when =1 represents upchirp signal, when =-1 represents a downchirp signal, K represents the modulated bit information, t represents time, j represents the imaginary unit, and B represents bandwidth.

[0166] The chirp signal is packaged as follows in the second step:

[0167] First, generate The number of preambles is generated according to the upchirp method. =1, K=0;

[0168] Then generate The number of downchirp signals, =-1, K=0, , Represents a configurable length; then the header data and the payload data (PL) data are combined into one symbol per SF, and the corresponding signal is generated according to the above chirp generation method; if the header data and the payload data (PL) data cannot be divided by SF, then they are rounded up.

[0169] The header data and the payload data are split into groups of L bits each. When the sum of the header data and the payload data is P bits, the header data and the payload data are divided into G groups: ;

[0170] Where ceil represents rounding up. If it is not an integer, then add a number of 0 bits after P until P is an integer multiple of L. The number of 0 bits Z added is expressed as: .

[0171] The G groups of data are packaged as follows: the first group of preambles, the first group of downchirps, the first group of headers, the first group of payload data, the second group of preambles, the second group of downchirps, the second group of headers, the second group of payload data, ... the Gth group of preambles, the Gth group of downchirps, the Gth group of headers, the Gth group of payload data;

[0172] The third step is as follows: Let the estimated delay result of the gth group be , the frequency deviation result of the g-th group estimation is , where 1≤ ≤G, and then perform delay compensation and frequency deviation compensation.

[0173] The third step is as follows: Let the frequency deviation result of the g-th group be , where 1≤ ≤G.

[0174] Get the gth group The methods for calculating the final CFO compensation value include the following:

[0175] Method A: The estimated result is used to compensate the header data and the payload data of the g-th group;

[0176] Method B: Set the data from group 1 to group g Taking the average, we get:

[0177] , and Compensate to the header data and payload data of the g-th group;

[0178] Method C: Set the data from group 1 to group g Taking the average, we get:

[0179] ,

[0180] and will Compensate into the header data and payload data of each group;

[0181] Method D: Calculate the mean and standard deviation of CFO:

[0182]

[0183]

[0184] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0185] The cfo weight of group g is ;

[0186] The final calculated It is expressed as follows:

[0187] ,

[0188] and will Compensate to the header and payload data of group g;

[0189] Method E: Calculate the mean and standard deviation of CFO:

[0190]

[0191]

[0192] in Represents the average value of G package cfo, Represents the standard deviation of the cfo value of the g-th package;

[0193] The cfo weight of group g is ;

[0194] The final calculated It is expressed as follows:

[0195] ,

[0196] and will Compensate to the header data and payload data of group g.

[0197] The first group of header data to the Gth group of header data after frequency offset compensation are averaged and then demodulated to obtain the header bit data;

[0198] Then, the first group of payload data to the Gth group of payload data are demodulated respectively, and finally the demodulated data are spliced ​​in sequence to obtain the received data packet, thus completing the communication process.

[0199] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A chirp communication method, characterized in that: The following steps are involved: Step 1: Generate chirp signal; Step 2: Packaging the generated chirp signal using a large spreading factor and small bandwidth packaging method; Step 3: Receive the chirp data after packetization and compensate for the frequency deviation; Step 4: Send the chirp data after frequency offset compensation to the demodulation module to obtain the data packet and complete the communication; The chirp signal packaging method in the second step is as follows: First, generate The number of preambles is generated according to the rule of generating upchirp signals, where =1, K=0; Then generate The number of downchirp signals, =-1, K=0, , Represents the configurable signal length; then the header data and the payload data are grouped according to the number of spreading factors, each group of data constitutes a symbol, and the corresponding signal is generated according to the above-mentioned chirp signal generation method; If the header data and payload data cannot be divided by SF, they are rounded up; The header data and the payload data are divided into groups of L bits each. When the sum of the header data and the payload data is P bits, the header data and the payload data are divided into G groups: ; Where ceil represents rounding up. If it is not an integer, then add a number of 0 bits after P until P is an integer multiple of L. The number of 0s added Z is expressed as: , L is the number of bits, P is the number of bits; The first grouping mode of the G groups of data is as follows: the first group of preambles, the first group of downchirps, the first group of headers, the first group of payload data, the second group of preambles, the second group of downchirps, the second group of headers, the second group of payload data, ... the Gth group of preambles, the Gth group of downchirps, the Gth group of headers, the Gth group of payload data; The second packaging method of the G groups of data is as follows: preamble, first group downchirp, first group header, first group payload data, second group downchirp, second group header, second group payload data, Gth group downchirp, Gth group header, Gth group payload data.

2. A chirp communication method according to claim 1, characterized in that: The specific process of generating the chirp signal in the first step is as follows: First, a modulated chirp symbol is generated according to the signal bandwidth BW, the spreading factor SF, and the modulated bit information. Represents the time length of a symbol, , Modulated signal It is expressed as: ， ， in is equal to 1 or -1, when When it is equal to 1, it represents the upchirp signal. When it is equal to -1, it represents a downchirp signal, K represents the modulated bit information, t represents time, j represents the imaginary unit, and B represents bandwidth.

3. A chirp communication method according to claim 2, characterized in that: After using the first packetization method, the process of receiving the chirp data after packetization and compensating the frequency offset is as follows: Let the estimated delay result of the gth group be , the frequency deviation result of the g-th group estimation is , where 1≤ ≤G, and then perform delay compensation and frequency deviation compensation.

4. A chirp communication method according to claim 3, characterized in that: The frequency offset compensation includes the following methods: Method 1: compensating the estimated delay result of the g-th group and the estimated frequency offset result of the g-th group into the header data and payload data of the g-th group; Method 2: average the delay results from the first group to the g-th group of data, and average the estimated delay results from the first group to the g-th group of data, and get: ， ， and will as well as Compensate to the header data and payload data of the g-th group; Method 3: Average the delay results from the first group to the Gth group of data, and average the frequency deviation results from the first group to the gth group of data, and get: ， ， and will as well as Compensate into the header data and payload data of each group; Method 4: First calculate the weight of each set of data: ， ， in Represents the average value of the delay result of the Gth packet, Represents the standard deviation of the delay result of the gth packet; The weight of the delay result of group g is , The final calculated It is expressed as follows: ; Calculate the mean and standard deviation of the frequency deviation results: in Represents the average value of the frequency deviation result of the Gth packet, Represents the standard deviation of the frequency deviation result of the gth packet; The frequency deviation result weight of group g is ; The final calculated It is expressed as follows: , and will as well as Compensate to the header data and payload data of the g-th group; Method 5: First calculate the weight of each set of data: in Represents the average value of the delay result of the Gth packet, Represents the standard deviation of the delay result of the gth packet; The delay result weight of group g is ; The final calculated It is expressed as follows: Calculate the mean and standard deviation of the frequency deviation results: in Represents the average value of the frequency deviation result of the Gth packet, Represents the standard deviation of the frequency deviation result of the gth packet; The frequency deviation result weight of group g is ; The final calculated It is expressed as follows: , and will as well as Compensate to the header data and payload data of the g-th group; Method 6: The weights obtained by arbitrarily combining the scattered results of methods 4 and 5 are used as the delay results and frequency deviation results for compensation.

5. A chirp communication method according to claim 4, characterized in that: After using the second packetization method, the process of receiving the chirp data after packetization and compensating the frequency offset is as follows: Let the frequency offset result of the g-th group be , where 1≤ ≤G.

6. A chirp communication method according to claim 5, characterized in that: Methods for calculating the compensation value of the final frequency deviation result after obtaining the frequency deviation result of the gth group include the following: Method A: The estimated result is compensated to the header data and payload data of the g-th group; Method B: Set the data from group 1 to group g Taking the average, we get: , and Compensate to the header data and payload data of the g-th group; Method C: average the frequency deviation results of the first to the Gth group of data to obtain: ， and will Compensate into the header data and payload data of each group; Method D: Calculate the mean and standard deviation of the frequency deviation results: in Represents the average value of the frequency deviation result of the Gth packet, Represents the standard deviation of the frequency deviation result of the gth packet; The frequency deviation result weight of group g is ; The final calculated It is expressed as follows: , and will Compensate to the header and payload data of group g; Method E: Calculate the mean and standard deviation of the frequency deviation results: in Represents the average value of the frequency deviation result of the Gth packet, Represents the standard deviation of the frequency deviation result value of the g-th packet; The frequency deviation result weight of group g is ; The final calculated It is expressed as follows: , and will Compensate to the header data and payload data of group g.

7. A chirp communication method according to claim 3 or 5, characterized in that: The fourth step is as follows: average the first group of header data to the Gth group of header data after frequency offset compensation and then demodulate to obtain the header bit data; Then, the first group of payload data to the Gth group of payload data are demodulated respectively, and finally the demodulated data are spliced ​​in sequence to obtain the received data packet, thus completing the communication process.

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