CN112636783B - A method, device and storage medium for generating frequency hopping pattern of power Internet of things - Google Patents

Abstract

The invention discloses a method, a device and a storage medium for generating a frequency hopping pattern of an electric power Internet of things.L frequency points are randomly selected in a frequency slot set to form a plurality of base sequences respectively, each frequency point in the frequency slot set is selected at least once and can be selected repeatedly, the plurality of base sequences form a sequence set, and a plurality of base sequences meeting the maximum Hamming correlation are selected in the sequence set to obtain a base sequence set; circularly and leftwards shifting each base sequence in the base sequence set to obtain f corresponding shift sequences; and (2) interweaving the f shift sequences to obtain a frequency hopping sequence corresponding to each base sequence, integrating the frequency hopping sequences to obtain an LHZ frequency hopping sequence set, wherein any two frequency hopping sequences in the LHZ frequency hopping sequence set have fewer frequency point collision times in the LHZ and no too many frequency point collision times outside the LHZ, and the frequency hopping sequences after shift combination have enough number and good frequency point randomness, so that the safe access of large-scale nodes provided by the power Internet of things frequency hopping communication system can be met.

Description

A method, device and storage medium for generating frequency hopping pattern of power Internet of things

technical field

The present invention relates to the technical field of frequency hopping communication, and in particular, to a method, device and storage medium for generating a frequency hopping pattern of the power Internet of things.

Background technique

With the continuous development of Energy Internet and Smart Grid, a variety of power high-service devices are connected to the power Internet of Things communication network. This communication network has the following characteristics: a large number of power service nodes (large-scale access), random access time (random access), and high information transmission security. In order to ensure the communication security of the power Internet of things, frequency hopping technology is an optimal communication transmission method. Frequency hopping technology can provide better multiple access capability and effectively avoid multi-node mutual interference and malicious interference. This technology has been widely used in traditional Internet of Things communication systems. The frequency hopping pattern is the core of the frequency hopping technology and determines the above characteristics of the frequency hopping technology. Usually the frequency hopping pattern consists of two parts, one is the frequency hopping frequency point table, in which all available frequency hopping frequency points are recorded; the other is the frequency hopping sequence, which is a pseudo-random sequence, from the frequency hopping frequency A specific number of frequency hopping points are selected in the point table according to a specific mathematical method, and a frequency hopping sequence, that is, a frequency hopping pattern, can be formed by these selected frequency hopping points.

In the power multi-service frequency hopping access communication network, within the scope of the main power station, a large number of service nodes access the network through the frequency hopping technology, and the access time of these nodes is random. In addition to the possible interference between different services and malicious jammers within the range of the main station, the current traditional pseudo-random frequency hopping patterns (including collision-free frequency hopping sequences and optimal random frequency hopping sequences), the number and frequency of traditional base sequences The number of point collisions is completely limited by the size of the frequency slot set, and large-scale node access cannot be achieved; secondly, the frequency point collision of the traditional base sequence is large under any delay, which is not conducive to the high reliability transmission requirements of power communication and cannot meet the frequency hopping. The number of sequences is large (to meet the access of a large number of nodes), the randomness of frequency hopping frequency points is good (to reduce malicious interference), and under any delay, the Hamming correlation value of frequency hopping sequences is small (to reduce user mutual interference).

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is that the traditional pseudo-random frequency hopping pattern cannot satisfy a large number of node access at the same time, the randomness of the frequency hopping frequency point is good, and the Hamming correlation value of the frequency hopping sequence at any time delay is small, and the purpose is to provide a power A method, device and storage medium for generating a frequency hopping pattern for the Internet of Things, selecting a frequency hopping sequence that satisfies the maximum Hamming correlation in a base sequence set composed of conventional frequency hopping sequences, and using a shift frequency hopping sequence interleaving method to generate random access low-collision frequency hopping The pattern provides secure access to large-scale nodes for the frequency hopping communication system of the power Internet of Things.

A method for generating a frequency hopping pattern for the Internet of Things in electric power, comprising the following steps:

Step S1, select multiple frequency points in the frequency slot set Fq, and randomly combine the multiple frequency points to obtain multiple base sequences with the number of frequency points L, and the multiple base sequences with the number of frequency points L form a sequence set;

Step S2, select a plurality of base sequences satisfying the maximum Hamming correlation from the described sequence set, and obtain the base sequence set S that the number of base sequences is M;

Step S3, cyclically shift each base sequence in the base sequence set S to the left, and obtain corresponding f shift sequences after each base sequence is cyclically shifted to the left;

Step S4: Interleave the f shift sequences to obtain a frequency hopping sequence corresponding to each base sequence, and finally obtain M frequency hopping sequences. The M frequency hopping sequences form a corresponding LHZ frequency hopping sequence set R.

Further, the frequency slot set Fq includes q frequency points available for hopping; the L frequency points in the base sequence include the q frequency points available for hopping, and the L ≥q, where, q is a natural number. Since the frequency points in the frequency slot set can be selected repeatedly and each frequency point is selected at least once, the base sequence not only includes all the frequency points in the frequency slot set, but also the number of frequency points in the base sequence is larger than that in the frequency slot set. number of frequency points.

Further, the value of the maximum Hamming correlation is Hm, and the specific calculation process is:

，0≤i ≤M-1，0≤ j ≤M-1，T1表示基序列长度为L时的相对时延，在计算最大汉明相关的值时满足0 ≤ T1≤ L-1。Wherein, Ha is the maximum Hamming autocorrelation of the base sequence set S , Hc is the maximum Hamming cross-correlation of the base sequence set S ; S ⁱ and S ^j are any two base sequences in the base sequence set S , S = { S ⁰ , S ¹ , ... , S ^{M -1} },

, 0 ≤ i ≤ M -1, 0 ≤ j ≤ M -1, T 1 represents the relative delay when the base sequence length is L, and 0 ≤ T 1 ≤ L-1 is satisfied when calculating the maximum Hamming correlation value.

Among them, the Hamming correlation function is:

；

;

，b和d表示频隙集Fq中的频点，上述汉明相关函数中的符号下标按模L运算，即除以L取余，T表示相对时延，相对时延的大小取决于序列长度。Among them, the function

, b and d represent the frequency points in the frequency slot set Fq. The symbol subscripts in the above Hamming correlation function are calculated according to the modulo L , that is, the remainder is divided by L, and T represents the relative delay. The size of the relative delay depends on the sequence length.

Further, the low collision zone LHZ size LHZ of the _LHZ frequency hopping sequence set R is:

；

;

Among them, H _a ( R ) and H _c ( R ) are two preset non-negative integers, L _AHZ is the Hamming autocorrelation low collision zone, L _CHZ is the Hamming cross correlation low collision zone, T 2 represents frequency hopping The relative latency of the sequence in the low-collision zone.

Further, the f shift sequences obtained in the step S3 are:

；

;

Among them, ke represents the number of bits that Si cyclically shifts to the left, e represents the setting parameter, e is a positive integer and satisfies ef = L , ^0≤k≤f - 1 , 0≤i≤M - 1 .

Further, in the step S4, the process of interweaving the f shift sequences obtained by cyclic left shifting of each base sequence is as follows:

中下标为

的元素

赋值给

，所述

为跳频序列中的元素，最终得到fL个元素；计算公式为：

；其中， 0≤ j ≤fL-1，

为j除以f取余数（即j模f计算），

为j除以f的取整数部分；the shift sequence

The middle subscript is

Elements

assign to

, the

is the element in the frequency hopping sequence, and finally fL elements are obtained; the calculation formula is:

; where, 0≤ j ≤ fL -1,

Divide j by f and take the remainder (i.e. j modulo f calculation),

is the integer part of j divided by f;

According to the obtained fL elements, the frequency hopping sequence Ri is formed, and the frequency hopping sequence Ri ^{is expressed} as:

；

;

According to the obtained frequency hopping sequence R ⁱ , the LHZ frequency hopping sequence set R is formed, and the LHZ frequency hopping sequence set R is expressed as:

。

.

In the power multi-service frequency hopping access communication network, within the range of the main power station, a large number of service nodes will access the network through frequency hopping technology. The access time of these nodes is random, except that there may be interference between different services, and the main Malicious jammers may also exist within the station range. The core of frequency hopping technology is the design of frequency hopping patterns. Traditional pseudo-random frequency hopping patterns (including collision-free frequency hopping sequences and optimal random frequency hopping sequences), traditional random frequency hopping sequences The number of collisions and the number of frequency point collisions are completely limited by the size of the frequency slot set, so large-scale node access cannot be achieved; secondly, the frequency point collision of the traditional base sequence is large under any delay, which is not conducive to the high reliability transmission requirements of power communication. The invention selects the frequency hopping sequence that satisfies the maximum Hamming correlation in the base sequence set composed of the conventional frequency hopping sequence to perform cyclic left shift, and uses the frequency hopping sequence after the cyclic left shift for interleaving to finally obtain the frequency hopping communication system that meets the requirements of the power Internet of Things and provides a large-scale The set of frequency hopping sequences for the secure access of the node, and all frequency points {f1, f2, ... , fq} in the frequency slot set Fq can be used by each frequency hopping sequence, that is, all frequencies in the frequency slot set Fq. Points can be selected repeatedly and each frequency point is selected at least once, so that the maximum processing gain can be achieved; in the generated frequency hopping sequence set, for any two frequency hopping sequences, during quasi-synchronous access, frequency point collision occurs The number of times is very small (the Hamming cross-correlation value is small), and the number of frequency collisions is slightly relaxed during asynchronous random access, which can effectively eliminate the interference between power service nodes; Compared with the excellent pseudo-random frequency hopping sequence, the number of the sequence number of the frequency hopping sequence set generated by the present invention is multiplied by the number of shift sequences generated after the cyclic left shift, so that the frequency hopping system can accommodate more power service nodes to access. , and for any frequency hopping sequence and its shift sequence in the frequency hopping sequence set, the number of frequency collisions between them is small, that is, the Hamming autocorrelation side lobe value is small. Under any time delay, the present invention considers the maximum Hamming correlation , including the maximum Hamming correlation of the frequency hopping sequence in the low collision zone LHZ and outside the low collision zone LHZ, so that any two frequency hopping sequences in the LHZ frequency hopping sequence set have fewer frequency collisions in the LHZ, and The number of frequency collisions outside the LHZ is not too many, the Hamming correlation value of the frequency hopping sequence is small, and the Hamming correlation value is the same number of corresponding bits for the same sequence or any two sequences under different delays; The frequency point collision is smaller than the traditional random frequency hopping pattern under the small delay; the frequency point collision is increased under the large delay but still smaller than the traditional low collision frequency hopping pattern.

Further, a device for generating a frequency hopping pattern for the Internet of Things in electric power, comprising:

A sequence set generating unit, used for selecting multiple frequency points from the frequency slot set Fq and performing random combination to obtain multiple base sequences with the number of frequency points being L, and the multiple base sequences with the number of frequency points being L to form a sequence set;

a base sequence set generating unit, used to select a plurality of base sequences satisfying the maximum Hamming correlation from the sequence set, and obtain a base sequence set S with M base sequences;

The shift unit is used to cyclically shift each base sequence in the base sequence set S to the left, to obtain f shift sequences corresponding to each base sequence;

The frequency hopping pattern generation unit is used for interleaving the f shift sequences corresponding to each base sequence to obtain corresponding frequency hopping sequences, and finally obtains M frequency hopping sequences, the M frequency hopping sequences form corresponding LHZ hopping sequences frequency sequence set R.

Further, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in the method of the present invention are implemented. The specific use of this method depends on a large amount of calculation, so the above calculation process is preferably realized by a computer program, so any computer program and storage medium including the protected steps in this method also belong to the protection scope of this application.

Further, an application method of a frequency hopping pattern of the power Internet of things, the frequency hopping system includes an LHZ frequency hopping sequence set R, and the frequency hopping system passes the large-scale service nodes in the power Internet of things communication network through the LHZ frequency hopping sequence. Set R, each service node is connected to the master station network through the power frequency hopping communication link to realize frequency hopping communication.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. A method, device and storage medium for generating a frequency hopping pattern of the power Internet of things of the present invention, based on the base sequence composed of conventional frequency hopping sequences, a frequency hopping sequence that satisfies the maximum Hamming correlation is selected to perform a cyclic left shift, and each frequency hopping sequence All the frequency points in the frequency slot set are included in the sequence, and the frequency points in the frequency slot can be repeatedly selected to achieve the maximum processing gain; in the generated frequency hopping sequence set, for any two frequency hopping sequences, in the standard During synchronous access, the number of frequency point collisions is very small (the Hamming cross-correlation value is small), while in asynchronous random access, the number of frequency point collisions is slightly larger, which can effectively eliminate the interference between power service nodes; The bit frequency hopping sequence combination method generates random access low-collision frequency hopping patterns, and the shift sequence generated after the cyclic left shift doubles the number of frequency hopping sequences, so that the frequency hopping system can accommodate more power service node connections. access to provide secure access to large-scale nodes for the frequency hopping communication system of the power Internet of things;

2. The present invention is a method, device and storage medium for generating a frequency hopping pattern of the power Internet of things. Under any time delay, the present invention takes into account the maximum Hamming correlation, including the frequency hopping sequence in the low collision zone LHZ and the low collision zone LHZ. The maximum Hamming correlation outside the LHZ frequency hopping sequence set makes any two frequency hopping sequences in the LHZ frequency hopping sequence set. The Hamming correlation value of the sequence is small, and the Hamming correlation value is the same number of corresponding bits for the same sequence or any two sequences under different delays; the frequency point collision is smaller than the traditional random frequency hopping pattern under the small delay; The frequency point collisions under the time delay have increased but are still smaller than the traditional low collision frequency hopping patterns.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the embodiments of the present invention, and constitute a part of the present application, and do not constitute limitations to the embodiments of the present invention. In the attached image:

1 is a schematic diagram of a data flow provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of a power multi-service communication access network based on frequency hopping.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. as a limitation of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail in order to avoid obscuring the present invention.

Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in the present invention in at least one embodiment. Thus, appearances of the phrases "one embodiment," "an embodiment," "one example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combination and/or subcombination in one or more embodiments or examples. Furthermore, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and that the drawings are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of the present invention, it should be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", The orientation or positional relationship indicated by "low", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated device or Elements must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the scope of the invention.

Example 1

As shown in FIG. 1, a method for generating a frequency hopping pattern for the Internet of Things in the present invention includes the following steps:

Step S1, select multiple frequency points in the frequency slot set Fq, and randomly combine the multiple frequency points to obtain multiple base sequences with the number of frequency points L, and the multiple base sequences with the number of frequency points L form a sequence set;

The frequency slot set Fq includes q frequency points available for hopping; the L frequency points in the base sequence include the q frequency points available for hopping, and L ≥q, where q is a natural number, Since the frequency points in the frequency slot set can be selected repeatedly and each frequency point is selected at least once, the base sequence not only includes all the frequency points in the frequency slot set, but also the number of frequency points in the base sequence is greater than the number of frequency points in the frequency slot set. number.

Step S2, select a plurality of base sequences that satisfy the maximum Hamming correlation from the sequence set, and obtain a base sequence set S whose base sequence number is M;

Wherein, the value of the maximum Hamming correlation is Hm, and the specific calculation process is:

，0≤ i ≤M-1，0≤ j ≤M-1，T1表示基序列长度为L时的相对时延，在计算最大汉明相关的值时满足0 ≤ T1≤ L-1；Wherein, Ha is the maximum Hamming autocorrelation of the base sequence set S , Hc is the maximum Hamming cross-correlation of the base sequence set S ; S ⁱ and S ^j are any two base sequences in the base sequence set S , S = { S ⁰ , S ¹ , ... , S ^{M -1} },

, 0≤ i ≤ M -1, 0≤ j ≤ M -1, T 1 represents the relative delay when the base sequence length is L, and 0 ≤ T 1 ≤ L-1 is satisfied when calculating the maximum Hamming correlation value;

Among them, the Hamming correlation function is:

；

;

，b和d表示频隙集Fq中的频点，上述汉明相关函数中的符号下标按模L运算，即除以L取余运算，T表示相对时延，相对时延的大小取决于序列长度。in,

, b and d represent the frequency points in the frequency slot set Fq, the symbol subscripts in the above Hamming correlation function are calculated according to the modulo L , that is, dividing by L and taking the remainder, T represents the relative delay, and the size of the relative delay depends on sequence length.

；其中，ke表示S ⁱ 循环左移的位数， e表示设定参数，e为正整数且满足ef= L，0≤k≤f-1，0≤i≤M-1。In step S3, each base sequence in the base sequence set S is cyclically shifted to the left, and after each base sequence is cyclically shifted to the left, corresponding f shift sequences are obtained; the shift sequence is expressed as:

; Among them, ke represents the number of bits that Si is shifted to the left cyclically, e represents the setting parameter, e is a positive integer and satisfies ef = L , ^0≤k≤f - 1 , 0≤i≤M - 1 .

Step S4: Interleave the f shift sequences to obtain a frequency hopping sequence corresponding to each base sequence, and finally obtain M frequency hopping sequences. The M frequency hopping sequences form a corresponding LHZ frequency hopping sequence set R.

In the above-mentioned step S4, the process of interweaving the f shift sequences obtained by cyclic left shifting of each base sequence is as follows:

中下标为

的元素

赋值给

，所述

为跳频序列中的元素，最终得到fL个元素；计算公式为：

；其中， 0≤ j ≤fL-1，

为j除以f取余数（即j模f计算），

为j除以f的取整数部分；the shift sequence

The middle subscript is

Elements

assign to

, the

is the element in the frequency hopping sequence, and finally fL elements are obtained; the calculation formula is:

; where, 0≤ j ≤ fL -1,

Divide j by f and take the remainder (i.e. j modulo f calculation),

is the integer part of j divided by f;

According to the obtained fL elements, the frequency hopping sequence Ri is formed, and the frequency hopping sequence Ri ^{is expressed} as:

；

;

According to the obtained frequency hopping sequence R ⁱ , the LHZ frequency hopping sequence set R is formed, and the LHZ frequency hopping sequence set R is expressed as:

。

.

The LHZ size LHZ of the low collision zone of the _LHZ frequency hopping sequence set R is:

；

;

Among them, H _a ( R ) and H _c ( R ) are two preset non-negative integers, L _AHZ is the Hamming autocorrelation low collision zone, L _CHZ is the Hamming cross correlation low collision zone, T 2 represents frequency hopping The relative delay of the sequence in the low collision zone; .

For the LHZ frequency hopping sequence set R , the maximum Hamming autocorrelation, the maximum Hamming cross correlation and the maximum Hamming correlation of the LHZ frequency hopping sequence set R outside the low collision area are also considered. The specific calculation process is as follows:

Among them, T 3 represents the relative delay when the sequence length of the frequency hopping sequence is fL , Z1 is an arbitrary positive integer, and 0 ≤ Z1 ≤ L _HZ .

In one embodiment, an apparatus for generating a frequency hopping pattern for the Internet of Things in electric power is used to implement the method steps in the above embodiments, including: a sequence set generating unit, configured to select multiple frequency points from the frequency slot set Fq to perform Randomly combining to obtain a plurality of base sequences with the number of frequency points L, the multiple base sequences with the number of frequency points of L form a sequence set;

a base sequence set generating unit, used to select a plurality of base sequences satisfying the maximum Hamming correlation from the sequence set, and obtain a base sequence set S with M base sequences;

The shift unit is used to cyclically shift each base sequence in the base sequence set S to the left, to obtain f shift sequences corresponding to each base sequence;

The frequency hopping pattern generation unit is used for interleaving the f shift sequences corresponding to each base sequence to obtain corresponding frequency hopping sequences, and finally obtains M frequency hopping sequences, the M frequency hopping sequences form corresponding LHZ hopping sequences frequency sequence set R.

In another embodiment, a computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps in the method of the present invention. The specific use of this method depends on a large amount of calculation, so the above calculation process is preferably realized by a computer program, so any computer program and storage medium including the protected steps in this method also belong to the protection scope of this application.

Based on another embodiment of the above-mentioned embodiment, a method for applying a frequency hopping pattern of the Internet of Things in electric power is provided. Through the LHZ frequency hopping sequence set R, each service node is connected to the master station network through the power frequency hopping communication link to realize frequency hopping communication.

As shown in Figure 2, in the power multi-service frequency hopping access communication network, within the scope of the main power station, a large number of service nodes will access the network through the frequency hopping technology, and the access time of these nodes is random, except between different services. There may be interference, and there may also be malicious jammers within the range of the main station. The core of frequency hopping technology is the design of frequency hopping patterns. Traditional pseudo-random frequency hopping patterns (including collision-free frequency hopping sequences and optimal random frequency hopping sequences), The number of traditional random frequency hopping sequences and the number of frequency point collisions are completely limited by the size of the frequency slot set, so large-scale node access cannot be achieved; secondly, the frequency point collision of the traditional base sequence is large under any delay, which is not conducive to high power communication. To meet the requirements of reliable transmission, the present invention selects the frequency hopping sequence that satisfies the maximum Hamming correlation in the base sequence set composed of the conventional frequency hopping sequence to perform a cyclic left shift, and uses the frequency hopping sequence after the cyclic left shift for interleaving to finally meet the requirements of the power Internet of Things hopping. The frequency communication system provides a set of frequency hopping sequences for secure access of large-scale nodes, and all frequency points {f1, f2, ... , fq} in the frequency slot set Fq can be used by each frequency hopping sequence, that is, frequency slots All the frequency points in the set Fq can be selected repeatedly and each frequency point is selected at least once, so that the maximum processing gain can be achieved; in the generated frequency hopping sequence set, for any two frequency hopping sequences, in the quasi-synchronous access When the number of frequency point collisions is small (the Hamming cross-correlation value is small), the number of frequency point collisions is slightly relaxed during asynchronous random access, which can effectively eliminate the interference between power service nodes; Compared with the traditional optimal pseudo-random frequency hopping sequence with the number q, the number of the sequence number of the frequency hopping sequence set generated by the present invention is multiplied by the number of shift sequences generated after the cyclic left shift, so that the frequency hopping system can accommodate more For any frequency hopping sequence and its shift sequence in the frequency hopping sequence set, the number of frequency collisions between the two is small, that is, the Hamming autocorrelation side lobe value is small. Under any delay, the present invention Taking into account the maximum Hamming correlation, including the maximum Hamming correlation of the frequency hopping sequence in the low collision zone LHZ and outside the low collision zone LHZ, so that any two frequency hopping sequences in the LHZ frequency hopping sequence set, the frequency of the two in the LHZ. The number of point collisions is small, and the number of frequency point collisions outside the LHZ is not too many. The Hamming correlation value of the frequency hopping sequence is small, and the Hamming correlation value is the same sequence or any two sequences corresponding to different delays. The number of bits is the same; the frequency collision is smaller than the traditional random frequency hopping pattern under the small delay; the frequency collision is increased under the large delay but still smaller than the traditional low collision frequency hopping pattern.

The theorem used in the present invention is: the frequency hopping sequence set R is the LHZ frequency hopping sequence set, the sequence length is f L , the size of the LHZ is Z = e -1, the maximum Hamming correlation in the LHZ is fH _m , and the maximum Hamming correlation in the LHZ is fH m . The maximum Hamming correlation is ( f -1) Hm ₊ L .

The proof of the above theorem is: Since the maximum Hamming correlation value of the frequency hopping sequence set S is H _m , according to the results of the interleaving technique, it is easy to obtain that R is the LHZ frequency hopping sequence set, and its LHZ size is Z = e -1. The maximum Hamming correlation of is fH _m ; and for the maximum Hamming correlation outside the LHZ, under the relative time delay T ≥ e , where R ⁱ , R ^j ∈ R, the Hamming correlation function is:

，如果要使

，则

。由此可求得存在唯一正整数n ₁=g，0≤g≤f-1，使得n ₂满足取0≤n ₂≤L-1任意值时，都有

；这样R ⁱ 、R ^j∈R的汉明相关函数变为：Case 1. When i = j . Because ef = L , when the relative delay satisfies T ≥ e , that is

, if you want to use

,but

. From this, it can be found that there is a unique positive integer n ₁ = g , 0≤ g ≤ f -1, so that when n ₂ satisfies any value of 0≤ n ₂ ≤L-1, there are

; so that the Hamming correlation function of R ⁱ , R ^j ∈ R becomes:

Case 2. When i ≠ j . The Hamming correlation function of R ⁱ , R ^j ∈ R is:

；

;

。In summary, the maximum Hamming correlation outside the LHZ is

.

Certificate completed.

Example 2

In order to better understand the implementation process of the method of the present invention, an example is provided. When q = 7, L = 16, and M = 3, a base sequence set S = { S ⁰ , S ¹ , S ² } is selected, where

It is easy to verify that the base sequence set S is the frequency hopping sequence set with the maximum Hamming correlation size of Hm = 2, and let e = 2, f = 8, then the shift sequence D = (0, 2, 4, ..., 14 can be obtained ). Then the frequency hopping sequence set R={R ⁰ , R ¹ , R ² } can be obtained, where:

It can be verified that the frequency hopping sequence set R is an LHZ frequency hopping sequence set whose LHZ size is Z=1, and its sequence length is 128. The maximum Hamming correlation within the LHZ is 16 and the maximum Hamming correlation outside the LHZ is 30.

It can be seen that not only the maximum Hamming correlation in the low collision zone LHZ is considered, but also the maximum Hamming correlation outside the low collision zone LHZ is considered. The number of collisions of frequency points in the interior is small, and the number of collisions of frequency points outside the LHZ is not too many, the number of frequency hopping sequences is sufficient, and the randomness of frequency points is good.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. A method for generating a frequency hopping pattern of the power Internet of Things, characterized in that, comprising the following steps: Step S1, select multiple frequency points in the frequency slot set Fq, and randomly combine the multiple frequency points to obtain multiple base sequences with the number of frequency points L, and the multiple base sequences with the number of frequency points L form a sequence set; Step S2, select a plurality of base sequences that satisfy the maximum Hamming correlation from the sequence set, and obtain a base sequence set S whose base sequence number is M; In step S3, each base sequence in the base sequence set S is cyclically shifted to the left by ke bits, and after each base sequence is cyclically shifted to the left, corresponding f shift sequences are obtained:

Among them, ke represents the number of bits of cyclic left shift of Si, e represents the setting parameter, e is a positive integer and satisfies ef=L, ^0≤k≤f -1, 0≤i≤M-1; In step S4, the f shift sequences are interleaved to obtain a frequency hopping sequence corresponding to each base sequence, and finally M frequency hopping sequences are obtained, and the M frequency hopping sequences form a corresponding LHZ frequency hopping sequence set R, specifically: The process is: The subscript in the shift sequence S ⁱ (ke) is

Elements

assign to

said

is the element in the frequency hopping sequence, and finally fL elements are obtained; the calculation formula is:

Among them, 0≤j≤fL-1, <j> _f is the remainder when j is divided by f,

is the integer part of j divided by f; According to the obtained ^fL elements, the frequency hopping sequence Ri is formed, and the frequency hopping sequence ^Ri is expressed as:

According to the obtained frequency hopping sequence R ⁱ , the LHZ frequency hopping sequence set R is formed, and the LHZ frequency hopping sequence set R is expressed as: R={R ⁰ , R ¹ , ..., R ^M-1 }. 2 . The method for generating a frequency hopping pattern for the Internet of Things in electric power according to claim 1 , wherein the frequency slot set Fq includes q frequency points available for hopping; the L frequency points in the base sequence include The q frequency points available for hopping, and the L≥q, where q is a natural number. 3. The method for generating a frequency hopping pattern for the Internet of Things in electric power according to claim 1, wherein the maximum Hamming correlation value is Hm, and the specific calculation process is: H _a ={H(S ⁱ , S ⁱ ; T1)|S ⁱ ∈S, 0≤T1≤L-1} H _c ={H(S ⁱ , S ^j ; T1)|S ⁱ , S ^j ∈ S, i≠j, 0≤T1≤L-1} H _m =max{H _a , H _c } Wherein, H _a is the maximum Hamming autocorrelation of the base sequence set S, Hc is the maximum Hamming cross-correlation of the base sequence set S; S ⁱ and S ^j are any two base sequences in the base sequence set S, S= {S ⁰ , S ¹ , ..., S ^M-1 },

0≤i≤M-1, 0≤j≤M-1, and T1 represents the relative delay when the base sequence length is L. 4. A kind of electric power Internet of Things frequency hopping pattern generation method according to claim 3, is characterized in that, the low collision zone LHZ size LHZ of described _LHZ frequency hopping sequence set R is: L _AHZ =max{T2|H(R ⁱ ,R ⁱ ;T2)≤H _a (R),R ⁱ ∈R} L _CHZ =max{T2|H(R ⁱ ,R ^j ;T2)≤H _c (R),R ⁱ ,R ^j ∈R,i≠j} L _HZ = min {L _AHZ , L _CHZ }; Among them, H _a (R) and H _c (R) are two preset non-negative integers, L _AHZ is the Hamming autocorrelation low collision zone, L _CHZ is the Hamming cross correlation low collision zone, and T2 represents the frequency hopping sequence Relative latency in the low collision zone. 5. A device for generating a frequency hopping pattern for the Internet of Things in electric power, characterized in that it comprises: A sequence set generating unit, used for selecting multiple frequency points from the frequency slot set Fq and performing random combination to obtain multiple base sequences with the number of frequency points being L, and the multiple base sequences with the number of frequency points being L to form a sequence set; a base sequence set generating unit, used to select a plurality of base sequences satisfying the maximum Hamming correlation from the sequence set, and obtain a base sequence set S with M base sequences; The shift unit is used to cyclically shift each base sequence in the base sequence set S by ke bits to the left. After each base sequence is cyclically shifted to the left, the corresponding f shift sequences are obtained:

Among them, ke represents the number of bits of cyclic left shift of Si, e represents the setting parameter, e is a positive integer and satisfies ef=L, ^0≤k≤f -1, 0≤i≤M-1; The frequency hopping pattern generation unit is used to subscript the shift sequence S ⁱ (ke) generated by the shift unit as

Elements

assign to

said

For the elements in the frequency hopping sequence, fL elements are finally obtained;

Among them, 0≤j≤fL-1, <j> _f is the remainder when j is divided by f,

is the integer part of j divided by f; According to the obtained fL elements, the frequency hopping sequence R ⁱ is formed:

According to the obtained frequency hopping sequence R ⁱ , the LHZ frequency hopping sequence set R is composed: R={R ⁰ , R ¹ , ..., R ^M-1 }. 6. The device for generating a frequency hopping pattern for the Internet of Things in electric power according to claim 5, wherein the maximum Hamming correlation value is Hm, and the specific calculation process is: H _a ={H(S ⁱ , S ⁱ ; T1)|S ⁱ ∈S, 0≤T1≤L-1} H _c ={H(S ⁱ , S ^j ; T1)|S ⁱ , S ^j ∈ S, i≠j, 0≤T1≤L-1} H _m =max{H _a , H _c } Wherein, Ha is the maximum Hamming autocorrelation of the base sequence set S, Hc is the maximum Hamming cross-correlation of the base sequence set S; S ⁱ and S ^j are any two base sequences in the base sequence set S, S= {S ⁰ , S ¹ , ..., S ^M-1 },

0≤i≤M-1, 0≤j≤M-1, and T1 represents the relative delay when the base sequence length is L. 7. The device for generating a frequency hopping pattern for the power Internet of Things according to claim 6, wherein the low collision zone LHZ size LHZ of the _LHZ frequency hopping sequence set R is: L _AHZ =max{T2|H(R ⁱ ,R ⁱ ;T2)≤H _a (R),R ⁱ ∈R} L _CHZ =max{T2|H(R ⁱ , R ^j ; T2)≤H _c (R), R ^t , R ^j ∈ R, i≠j} L _HZ = min {L _AHZ , L _CHZ }; Among them, H _a (R) and H _c (R) are two preset non-negative integers, L _AHZ is the Hamming autocorrelation low collision zone, L _CHZ is the Hamming cross correlation low collision zone, and T2 represents the frequency hopping sequence Relative latency in the low collision zone. 8. A computer-readable storage medium, characterized in that a computer program is stored thereon, and the computer program implements the method of any one of claims 1-4 when running.

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