CN112636783B - Power Internet of things frequency hopping pattern generation method and device and storage medium - Google Patents
Power Internet of things frequency hopping pattern generation method and device and storage medium Download PDFInfo
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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
Technical Field
The invention relates to the technical field of frequency hopping communication, in particular to a method and a device for generating a frequency hopping pattern of an electric power internet of things and a storage medium.
Background
With the continuous development of energy internet and smart grid, various electric power high-business devices are accessed to an electric power internet of things communication network. Such a communication network has the following features: the power service nodes are numerous (large-scale access), the access time is random (random access), the information transmission safety is high, and the like. In order to ensure the communication safety of the power internet of things, the frequency hopping technology is an optimal communication transmission mode. The frequency hopping technology can provide better multiple access capability and effectively avoid mutual interference and malicious interference of multiple nodes, and the technology is widely applied to the traditional Internet of things communication system. The hopping pattern is the core of the hopping technique and determines the above-mentioned characteristics of the hopping technique. Usually, a frequency hopping pattern is composed of two parts, one is a frequency hopping frequency point table, and all available frequency hopping frequency points are recorded in the frequency hopping frequency point table; one is a frequency hopping sequence which is a pseudo random sequence, a specific number of frequency hopping points are selected from a frequency hopping point table according to a specific mathematical method, and a frequency hopping sequence, namely a frequency hopping pattern, can be formed by the selected frequency hopping points.
In the power multi-service frequency hopping access communication network, a large number of service nodes are accessed to the network through a frequency hopping technology within the range of a power master station, and the access time of the nodes is random. Except that interference may exist among different services and a malicious jammer may exist in the range of a master station, the number of conventional base sequences and the frequency point collision frequency of the conventional pseudo-random frequency hopping pattern (including a collision-free frequency hopping sequence and an optimal random frequency hopping sequence) are completely limited by the size of a frequency slot set at present, and large-scale node access cannot be realized; secondly, frequency point collision of the traditional base sequence is large under any time delay, the requirement of high-reliability transmission of power communication is not facilitated, the number of frequency hopping sequences cannot be met (meeting the access of a large number of nodes), the randomness of the frequency hopping points is good (reducing malicious interference), and the Hamming correlation value of the frequency hopping sequences is small (reducing mutual interference of users) under any time delay.
Disclosure of Invention
The invention aims to solve the technical problems that the traditional pseudo-random frequency hopping pattern cannot simultaneously meet the requirements of access of a large number of nodes, the frequency hopping frequency point randomness is good, and the Hamming correlation value of a frequency hopping sequence under any time delay is small, and aims to provide a method, a device and a storage medium for generating the frequency hopping pattern of the power internet of things.
A frequency hopping pattern generation method for an electric power Internet of things comprises the following steps:
step S1, selecting a plurality of frequency points in a frequency slot set Fq, and randomly combining the frequency points to obtain a plurality of base sequences with the frequency point number of L, wherein the base sequences with the frequency point number of L form a sequence set;
step S2, selecting a plurality of base sequences meeting the maximum Hamming correlation from the sequence set to obtain a base sequence set with the number M of the base sequencesS；
Step S3, each base sequence in the base sequence set S is circularly and leftwards moved, and each base sequence is correspondingly obtained after being circularly and leftwards movedfA strip shift sequence;
step S4, thefAnd mutually interweaving the shift sequences to obtain a frequency hopping sequence corresponding to each base sequence, and finally obtaining M frequency hopping sequences, wherein the M frequency hopping sequences form a corresponding LHZ frequency hopping sequence set R.
Further, the frequency slot set Fq includes q frequency points for hopping; the L frequency points in the base sequence comprise the q frequency points for jumping, and L is more than or equal to q, wherein q is a natural number, and the frequency points in the frequency slot set can be selected repeatedly and each frequency point is selected at least once, so that the base sequence not only comprises all the frequency points in the frequency slot set, but also the number of the frequency points in the base sequence is greater than that of the frequency points in the frequency slot set.
Further, the maximum hamming related value is Hm, and the specific calculation process is as follows:
wherein,Hais the base sequence setSThe maximum of the self-correlation of the hamming,Hcas a set of base sequencesSMaximum hamming cross-correlation of;S i 、S j as a set of base sequencesSAny two of the base sequences of (a),S= {S 0, S 1, ... , S M-1}，
，0≤ i ≤M-1，0≤ j ≤M-1，T1 represents the relative time delay when the length of the base sequence is L, and the maximum Hamming related value is calculated and meets the condition that 0 is less than or equal toT1≤ L-1。
Wherein the Hamming correlation function is:
wherein the function
B and d represent the frequency points in the frequency slot set Fq, and the symbol subscripts in the Hamming correlation function are in modulo orderLThe operation, i.e. division by L, is left, T representing the relative delay, the size of which depends on the sequence length.
Further, the size of the LHZ low collision zone LHZ of the LHZ frequency hopping sequence set RL HZ Comprises the following steps:
wherein,H a (R) AndH c (R) Is two preset non-negative integers,L AHZ is a hamming self-correlation low collision region,L CHZ for the hamming cross-correlation low collision zone,T2 denotes the relative delay of the hopping sequence in the low collision zone.
Further, the step S3 is obtainedfThe bar shift sequences are:
wherein ke representsS i The number of bits to be shifted left in the loop,eit is shown that the set-up parameters,eis a positive integer and satisfiesef= L，0≤k≤f-1，0≤i≤M-1。
Further, theIn step S4, each base sequence is circularly left shiftedfThe process of interleaving the strip shift sequences comprises the following steps:
shifting the sequence
Middle subscript of
Of (2) element(s)
Is assigned to
Said
Are elements in the frequency hopping sequence to obtainfLAn element; the calculation formula is as follows:
(ii) a Wherein, 0 is less than or equal toj ≤fL-1，
Is composed ofjIs divided byfTaking the remainder (i.e. j modulo f calculation),
an integer part of j divided by f;
according to obtainingfLElements forming a hopping sequenceR i Frequency hopping sequenceR i Expressed as:
according to the obtained frequency hopping sequenceR i Forming an LHZ frequency hopping sequence set R, wherein the LHZ frequency hopping sequence set R is expressed as:
in the electric power multi-service frequency hopping access communication network, a large number of service nodes can access the network through a frequency hopping technology within an electric power master station range, the access time of the nodes is random, except that interference may exist among different services, malicious jammers may exist within the master station range, the core of the frequency hopping technology is the design of a frequency hopping pattern, the traditional pseudo-random frequency hopping pattern (comprising a collision-free frequency hopping sequence and an optimal random frequency hopping sequence) is completely limited by the size of a frequency slot set, and large-scale node access cannot be realized; secondly, under any time delay, the frequency point collision of the traditional base sequence is large, and the high-reliability transmission requirement of power communication is not facilitated, the frequency hopping sequence meeting the maximum Hamming correlation is selected from the base sequence set consisting of the conventional frequency hopping sequences to carry out circular left shift, the frequency hopping sequences after the circular left shift are utilized to carry out interweaving, and finally, the frequency hopping sequence set meeting the requirement that the power Internet of things frequency hopping communication system provides safe access of large-scale nodes is obtained, and all the frequency points { f1, f2,. fara, Fq } in the frequency slot set Fq can be used by each frequency hopping sequence, namely all the frequency points in the frequency slot set Fq can be selected repeatedly and each frequency point is selected at least once, so that the maximum processing gain can be realized; in the generated frequency hopping sequence set, for any two frequency hopping sequences, the frequency point collision frequency is very small (the Hamming cross-correlation value is small) when the quasi-synchronous access is performed, and the frequency point collision frequency is slightly widened when the asynchronous random access is performed, so that the interference between power service nodes can be effectively eliminated; compared with the traditional optimal pseudo-random frequency hopping sequence with the same frequency point number q, the frequency hopping sequence set generated by the invention has the advantages that the number of the sequences is multiplied after the cyclic left shift, so that the frequency hopping system can accommodate more power service nodes for access, and for any hopping sequence and its shift sequence in the hopping sequence set, the frequency point collision times of the two are few, i.e. the Hamming autocorrelation sidelobe value is small, under any time delay, the 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 the frequency point collision times of any two frequency hopping sequences in the LHZ frequency hopping sequence set in the LHZ are less, the frequency point collision times outside the LHZ are not too many, the Hamming related value of the frequency hopping sequence is small, and the Hamming related value is the number of the same sequence or any two sequences corresponding to the same bit under different time delays; the frequency point collision is smaller than that of the traditional random frequency hopping pattern under the small time delay; frequency point collisions are increased with large delays but still smaller than conventional low collision hopping patterns.
Further, a power internet of things frequency hopping pattern generation device includes:
the frequency slot set Fq is used for selecting a plurality of frequency points from the frequency slot set Fq to carry out random combination to obtain a plurality of base sequences with the frequency point number of L, and the base sequences with the frequency point number of L form a sequence set;
the base sequence set generating unit is used for selecting a plurality of base sequences meeting the maximum Hamming correlation from the sequence set to obtain a base sequence set S with the number of the base sequences being M;
a shift unit for respectively circularly left-shifting each base sequence in the base sequence set S to obtain the corresponding base sequencefA strip shift sequence;
a frequency hopping pattern generating unit for corresponding each base sequencefAnd mutually interweaving the shift sequences to obtain corresponding frequency hopping sequences, and finally obtaining M frequency hopping sequences which form a corresponding LHZ frequency hopping sequence set R.
Further, a computer-readable storage medium stores a computer program which, when executed by a processor, implements the steps in the method of the invention. The specific use of the method relies on a large number of calculations and it is therefore preferred that the above calculation is performed by a computer program, so any computer program and its storage medium containing the steps protected in the method also fall within the scope of the present application.
Furthermore, the frequency hopping system comprises a LHZ frequency hopping sequence set R, and the frequency hopping system enables large-scale service nodes in the power Internet of things communication network to pass through the LHZ frequency hopping sequence set R and enables all the service nodes to be accessed into the master station network through the power frequency hopping communication link, so that frequency hopping communication is achieved.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. according to the method, the device and the storage medium for generating the frequency hopping pattern of the power internet of things, the frequency hopping sequences meeting the maximum Hamming correlation are selected in a base sequence set consisting of conventional frequency hopping sequences to carry out circular left shift, each frequency hopping sequence comprises all frequency points in a frequency slot set, and the frequency points in the frequency slots can be selected repeatedly to realize the maximum processing gain; in the generated frequency hopping sequence set, for any two frequency hopping sequences, the frequency point collision frequency is very small (the Hamming cross-correlation value is small) when the quasi-synchronous access is performed, and the frequency point collision frequency is slightly wider when the asynchronous random access is performed, so that the interference between power service nodes can be effectively eliminated; the random access low-collision frequency hopping pattern is generated by adopting a shift frequency hopping sequence combination method, and the number of the frequency hopping sequences is multiplied by the shift sequence generated after cyclic left shift, so that a frequency hopping system can accommodate more power service nodes for access, and the safe access of large-scale nodes is provided for a power Internet of things frequency hopping communication system;
2. the invention relates to a method, a device and a storage medium for generating frequency hopping patterns of an electric power internet of things, wherein under any time delay, the method considers the maximum Hamming correlation, including the maximum Hamming correlation of frequency hopping sequences in a low collision zone LHZ and outside the low collision zone LHZ, so that any two frequency hopping sequences in an LHZ frequency hopping sequence set have fewer frequency point collision times in the LHZ, the frequency point collision times outside the LHZ are not too many, the Hamming correlation values of the frequency hopping sequences are small, and the Hamming correlation values are the same sequence or the same number of corresponding bits of any two sequences under different time delays; the frequency point collision is smaller than that of the traditional random frequency hopping pattern under the small time delay; frequency point collisions are increased with large delays but still smaller than conventional low collision hopping patterns.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic diagram of a data flow provided by 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 Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: it is not necessary to employ these specific details to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail so as not to obscure the present invention.
Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the invention. Thus, the 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 sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and 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 is to be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore, are not to be construed as limiting the scope of the present invention.
Example 1
As shown in fig. 1, the method for generating a frequency hopping pattern of an electric power internet of things of the invention comprises the following steps:
step S1, selecting a plurality of frequency points in a frequency slot set Fq, and randomly combining the frequency points to obtain a plurality of base sequences with the frequency point number of L, wherein the base sequences with the frequency point number of L form a sequence set;
the frequency slot set Fq comprises q frequency points for jumping; the L frequency points in the base sequence comprise the q frequency points for jumping, and L is more than or equal to q, wherein q is a natural number, and the frequency points in the frequency slot set can be selected repeatedly and each frequency point is selected at least once, so that the base sequence not only comprises all the frequency points in the frequency slot set, but also the number of the frequency points in the base sequence is greater than that of the frequency points in the frequency slot set.
S2, selecting a plurality of base sequences meeting the maximum Hamming correlation from the sequence set to obtain a base sequence set S with the number of the base sequences being M;
wherein, the maximum hamming related value is Hm, and the specific calculation process is as follows:
wherein,Hais the base sequence setSThe maximum of the self-correlation of the hamming,Hcas a set of base sequencesSMaximum hamming cross-correlation of;S i 、S j as a set of base sequencesSAny two of the base sequences of (a),S= {S 0, S 1, ... , S M-1}，
，0≤ i ≤M-1，0≤ j ≤M-1，T1 represents the relative time delay when the length of the base sequence is L, and the maximum Hamming related value is calculated and meets the condition that 0 is less than or equal toT1≤ L-1；
Wherein the Hamming correlation function is:
wherein,
b and d represent the frequency points in the frequency slot set Fq, and the symbol subscripts in the Hamming correlation function are in modulo orderLThe operation, i.e. the division by L remainder operation, T denotes the relative delay, the size of which depends on the sequence length.
Step S3, each base sequence in the base sequence set S is circularly and leftwards moved, and each base sequence is circularly and leftwards moved to obtain f corresponding shift sequences; the shift sequence is represented as:
(ii) a Wherein ke representsS i The number of bits to be shifted left in the loop, eit is shown that the set-up parameters,eis a positive integer and satisfiesef= L，0≤k≤f-1，0≤i≤M-1。
And step S4, mutually interweaving the f shift sequences to obtain a frequency hopping sequence corresponding to each base sequence, and finally obtaining M frequency hopping sequences which form a corresponding LHZ frequency hopping sequence set R.
Obtained by circularly left-shifting each base sequence in the step S4fThe process of interleaving the strip shift sequences comprises the following steps:
shifting the sequence
Middle subscript of
Of (2) element(s)
Is assigned to
Said
Are elements in the frequency hopping sequence to obtainfLAn element; the calculation formula is as follows:
(ii) a Wherein, 0 is less than or equal toj ≤fL-1，
Is composed ofjIs divided byfTaking the remainder (i.e. j modulo f calculation),
an integer part of j divided by f;
according to obtainingfLElements forming a hopping sequenceR i Frequency hopping sequenceR i Expressed as:
according to the obtained frequency hopping sequenceR i Forming an LHZ frequency hopping sequence set R, wherein the LHZ frequency hopping sequence set R is expressed as:
the LHZ size of the low collision zone LHZ of the LHZ frequency hopping sequence set RL HZ Comprises the following steps:
wherein,H a (R) AndH c (R) Is two preset non-negative integers,L AHZ is a hamming self-correlation low collision region,L CHZ for the hamming cross-correlation low collision zone,T2 represents the relative time delay of the frequency hopping sequence in a low collision zone; .
For LHZ hopping sequence setRMaximum Hamming autocorrelation, maximum Hamming cross-correlation and maximum Hamming correlation of an LHZ frequency hopping sequence set R outside a low collision region are also considered, and the specific calculation process is as follows:
wherein,T3 sequence length of the hopping sequence isfLThe relative time delay of the time, Z1 is any positive integer, and Z1 is more than or equal to 0 and is more than or equal to LHZ。
In an embodiment, an apparatus for generating a frequency hopping pattern of an electric internet of things is used to implement the method steps in the above embodiment, and includes: the frequency slot set Fq is used for selecting a plurality of frequency points from the frequency slot set Fq to carry out random combination to obtain a plurality of base sequences with the frequency point number of L, and the base sequences with the frequency point number of L form a sequence set;
the base sequence set generating unit is used for selecting a plurality of base sequences meeting the maximum Hamming correlation from the sequence set to obtain a base sequence set S with the number of the base sequences being M;
a shift unit for respectively circularly left-shifting each base sequence in the base sequence set S to obtain the corresponding base sequencefA strip shift sequence;
a frequency hopping pattern generating unit for corresponding each base sequencefAnd mutually interweaving the shift sequences to obtain corresponding frequency hopping sequences, and finally obtaining M frequency hopping sequences which form a corresponding LHZ frequency hopping sequence set R.
In another embodiment, a computer-readable storage medium stores a computer program which, when executed by a processor, performs the steps in the method of the invention. The specific use of the method relies on a large number of calculations and it is therefore preferred that the above calculation is performed by a computer program, so any computer program and its storage medium containing the steps protected in the method also fall within the scope of the present application.
Based on another embodiment of the above embodiments, an application method of a frequency hopping pattern of an electric power internet of things includes a LHZ frequency hopping sequence set R in a frequency hopping system, and the frequency hopping system accesses large-scale service nodes in an electric power internet of things communication network into a master station network through an electric power frequency hopping communication link through the LHZ frequency hopping sequence set R, so as to implement frequency hopping communication.
As shown in fig. 2, in the power multi-service frequency hopping access communication network, a large number of service nodes can access the network through a frequency hopping technology within a power master station, the access time of the nodes is random, except that interference may exist between different services, and a malicious jammer may also exist within the master station, the core of the frequency hopping technology is the design of a frequency hopping pattern, a traditional pseudo-random frequency hopping pattern (including a collision-free frequency hopping sequence and an optimal random frequency hopping sequence) is completely limited by the size of a frequency slot set, and large-scale node access cannot be realized; secondly, under any time delay, the frequency point collision of the traditional base sequence is large, and the high-reliability transmission requirement of power communication is not facilitated, the frequency hopping sequence meeting the maximum Hamming correlation is selected from the base sequence set consisting of the conventional frequency hopping sequences to carry out circular left shift, the frequency hopping sequences after the circular left shift are utilized to carry out interweaving, and finally, the frequency hopping sequence set meeting the requirement that the power Internet of things frequency hopping communication system provides safe access of large-scale nodes is obtained, and all the frequency points { f1, f2,. fara, Fq } in the frequency slot set Fq can be used by each frequency hopping sequence, namely all the frequency points in the frequency slot set Fq can be selected repeatedly and each frequency point is selected at least once, so that the maximum processing gain can be realized; in the generated frequency hopping sequence set, for any two frequency hopping sequences, the frequency point collision frequency is very small (the Hamming cross-correlation value is small) when the quasi-synchronous access is performed, and the frequency point collision frequency is slightly widened when the asynchronous random access is performed, so that the interference between power service nodes can be effectively eliminated; compared with the traditional optimal pseudo-random frequency hopping sequence with the same frequency point number q, the frequency hopping sequence set generated by the invention has the advantages that the number of the sequences is multiplied after the cyclic left shift, so that the frequency hopping system can accommodate more power service nodes for access, and for any hopping sequence and its shift sequence in the hopping sequence set, the frequency point collision times of the two are few, i.e. the Hamming autocorrelation sidelobe value is small, under any time delay, the 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 the frequency point collision times of any two frequency hopping sequences in the LHZ frequency hopping sequence set in the LHZ are less, the frequency point collision times outside the LHZ are not too many, the Hamming related value of the frequency hopping sequence is small, and the Hamming related value is the number of the same sequence or any two sequences corresponding to the same bit under different time delays; the frequency point collision is smaller than that of the traditional random frequency hopping pattern under the small time delay; frequency point collisions are increased with large delays but still smaller than conventional low collision hopping patterns.
The theorem used in the invention is as follows: the frequency hopping sequence set R is an LHZ frequency hopping sequence set, and the sequence length isf LLHZ size is Z =e-1, maximum Hamming correlation in LHZ isfH m The maximum Hamming correlation outside the LHZ is: (f-1）H m +L。
The proof of the above theorem is: due to frequency hopping sequence setSHas a maximum Hamming correlation value ofH m Easily obtained according to the interleaving technique resultRIs an LHZ frequency hopping sequence set, the LHZ size of which is Z =e-1, maximum Hamming correlation in LHZ isfH m (ii) a And for maximum Hamming correlation outside the LHZ, at relative time delayT≥eWhereinR i 、R jE.r, hamming correlation function is:
case 2 wheni ≠ jThen (c) is performed.R i 、R jThe Hamming correlation function for e.R is:
in summary, the maximum Hamming correlation outside the LHZ is
。
After the syndrome is confirmed.
Example 2
To better understand the implementation of the method of the present invention, an example is provided, when q = 7, L = 16, and M = 3, the base sequence is selectedCollectionS={S 0，S 1，S 2Therein of
It is easy to verify that the base sequence set S is a frequency hopping sequence set with a maximum hamming correlation size Hm =2, let e =2, and f = 8, then the shift sequence D = (0, 2, 4, …, 14) can be obtained. Then a hopping sequence set R = { R } can be obtained0，R1，R2}, wherein:
it can be verified that the hopping sequence set R is a LHZ hopping sequence set with a LHZ size Z =1, and the sequence length thereof is 128. The maximum hamming correlation within the LHZ is 16 and the maximum hamming correlation outside the LHZ is 30.
Therefore, the maximum Hamming correlation in the low collision zone LHZ and the maximum Hamming correlation outside the low collision zone LHZ are considered, and for any frequency hopping sequence and any translation sequence thereof in the frequency hopping sequence set, the frequency point collision times of the frequency hopping sequence and the translation sequence in the LHZ are few, the frequency point collision times outside the LHZ are not too many, the number of the frequency hopping sequences is enough, and the frequency point randomness is good.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. A frequency hopping pattern generation method of an electric power Internet of things is characterized by comprising the following steps:
step S1, selecting a plurality of frequency points in a frequency slot set Fq, and randomly combining the frequency points to obtain a plurality of base sequences with the frequency point number of L, wherein the base sequences with the frequency point number of L form a sequence set;
s2, selecting a plurality of base sequences meeting the maximum Hamming correlation from the sequence set to obtain a base sequence set S with the number of the base sequences being M;
step S3, respectively performing left shift ke on each base sequence in the base sequence set S, and obtaining f corresponding shift sequences after each base sequence is performed left shift:
wherein ke represents SiThe digit of the cyclic left shift, e represents a set parameter, e is a positive integer and satisfies ef ═ L, k is more than or equal to 0 and less than or equal to f-1, and i is more than or equal to 0 and less than or equal to M-1;
step S4, the f shift sequences are interleaved with each other to obtain a frequency hopping sequence corresponding to each base sequence, and finally M frequency hopping sequences are obtained, wherein the M frequency hopping sequences form a corresponding LHZ frequency hopping sequence set R, and the specific process is as follows:
the shift sequence Si(ke) middle subscript
Of (2) element(s)
Is assigned to
The above-mentioned
The fL elements are obtained finally for the elements in the frequency hopping sequence; the calculation formula is as follows:
wherein j is more than or equal to 0 and less than or equal to fL-1,<j>fis j divided by fThe remainder of the process is,
an integer part of j divided by f;
forming a frequency hopping sequence R according to the obtained fL elementsiFrequency hopping sequence RiExpressed as:
according to the obtained frequency hopping sequence RiForming an LHZ frequency hopping sequence set R, wherein the LHZ frequency hopping sequence set R is expressed as:
R＝{R0，R1，…，RM-1}。
2. the method for generating the frequency hopping pattern of the power internet of things according to claim 1, wherein the frequency slot set Fq comprises q frequency points for hopping; and the L frequency points in the base sequence comprise the q frequency points for hopping, and L is more than or equal to q, wherein q is a natural number.
3. The method for generating the frequency hopping pattern of the power internet of things according to claim 1, wherein the maximum hamming related value is Hm, and the specific calculation process is as follows:
Ha＝{H(Si，Si；T1)|Si∈S，0≤T1≤L-1}
Hc＝{H(Si，Sj；T1)|Si，Sj∈S，i≠j，0≤T1≤L-1}
Hm＝max{Ha，Hc}
wherein HaThe maximum Hamming self-correlation of the base sequence set S is obtained, and Hc is the maximum Hamming cross-correlation of the base sequence set S; si、SjFor any two base sequences in the base sequence set S, S ═ S0，S1，...，SM-1}，
I is more than or equal to 0 and less than or equal to M-1, j is more than or equal to 0 and less than or equal to M-1, and T1 represents the relative time delay when the length of the base sequence is L.
4. The method for generating power Internet of things frequency hopping pattern according to claim 3, wherein the LHZ frequency hopping sequence set R is in a low collision zone LHZ size LHZComprises the following steps:
LAHZ＝max{T2|H(Ri，Ri；T2)≤Ha(R)，Ri∈R}
LCHZ＝max{T2|H(Ri，Rj；T2)≤Hc(R)，Ri，Rj∈R，i≠j}
LHZ＝min{LAHZ，LCHZ}；
wherein Ha(R) and Hc(R) is two preset non-negative integers, LAHZIs a Hamming autocorrelation low collision region, LCHZFor a hamming cross-correlation low collision zone, T2 represents the relative delay of the hopping sequence in the low collision zone.
5. An electric power thing networking frequency hopping pattern generation device, characterized by includes:
the frequency slot set Fq is used for selecting a plurality of frequency points from the frequency slot set Fq to carry out random combination to obtain a plurality of base sequences with the frequency point number of L, and the base sequences with the frequency point number of L form a sequence set;
the base sequence set generating unit is used for selecting a plurality of base sequences meeting the maximum Hamming correlation from the sequence set to obtain a base sequence set S with the number of the base sequences being M;
a shift unit, configured to respectively cycle left shift ke of each base sequence in the base sequence set S, and obtain f corresponding shift sequences after cycle left shift of each base sequence:
wherein ke represents SiThe digit of the cyclic left shift, e represents a set parameter, e is a positive integer and satisfies ef ═ L, k is more than or equal to 0 and less than or equal to f-1, and i is more than or equal to 0 and less than or equal to M-1;
a hopping pattern generating unit for generating the shift sequence S generated by the shifting uniti(ke) middle subscript
Of (2) element(s)
Is assigned to
The above-mentioned
The fL elements are obtained finally for the elements in the frequency hopping sequence;
wherein j is more than or equal to 0 and less than or equal to fL-1,<j>fthe remainder is taken as the division of j by f,
an integer part of j divided by f;
forming a frequency hopping sequence R according to the obtained fL elementsi：
According to the obtained frequency hopping sequence RiForming an LHZ frequency hopping sequence set R:
R＝{R0，R1，…，RM-1}。
6. the device for generating frequency hopping pattern of internet of things as claimed in claim 5, wherein the maximum Hamming related value is Hm, and the specific calculation process is as follows:
Ha＝{H(Si，Si；T1)|Si∈S，0≤T1≤L-1}
Hc＝{H(Si，Sj；T1)|Si，Sj∈S，i≠j，0≤T1≤L-1}
Hm＝max{Ha，Hc}
wherein Ha is the maximum Hamming self-correlation of the base sequence set S, and Hc is the maximum Hamming cross-correlation of the base sequence set S; si、SjIs any two base sequences in the base sequence set S, S ═ S0，S1，...，SM-1}，
I is more than or equal to 0 and less than or equal to M-1, j is more than or equal to 0 and less than or equal to M-1, and T1 represents the relative time delay when the length of the base sequence is L.
7. The device of claim 6, wherein the LHZ hopping sequence set R has a low collision zone LHZ size LHZComprises the following steps:
LAHZ＝max{T2|H(Ri，Ri；T2)≤Ha(R)，Ri∈R}
LCHZ＝max{T2|H(Ri，Rj；T2)≤Hc(R)，Rt，Rj∈R，i≠j}
LHZ＝min{LAHZ，LCHZ}；
wherein Ha(R) and Hc(R) is two preset non-negative integers, LAHZIs a Hamming autocorrelation low collision region, LCHZFor a hamming cross-correlation low collision zone, T2 represents the relative delay of the hopping sequence in the low collision zone.
8. A computer-readable storage medium, on which a computer program is stored which, when executed, implements the method of any of claims 1-4.
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