Construction method of high-capacity wide-interval frequency hopping sequence set

Abstract

The invention discloses a construction method of a high-capacity wide-interval frequency hopping sequence set, and relates to the technical field of wireless communication. According to the method, all frequencies in an initial frequency set are permutated and combined, any non-coincident or primary coincident sequence set on the initial frequency set is constructed to serve as a base sequence set, and any k sequences are selected from the base sequence set to serve as alternative sequences; the method comprises the following steps of: traversing all k sequences in a base sequence set to update alternative sequences, processing the alternative sequences to enable the frequency of a t-th position of each processed alternative sequence to be unequal to the frequency of a (t + 1)-th position, and then constructing a wide-interval frequency hopping sequence according to each processed alternative sequence, and traversing all k sequences in the base sequence set to update the alternative sequences, a high-capacity wide-interval frequency hopping sequence set containing a plurality of sequences can be obtained through multi-round construction, and the Hamming correlation is optimal. According to the invention, the anti-interference performance of the frequency hopping communication system can be improved, and the frequency hopping networking capability and the user capacity can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of wireless communications, and in particular to a method for constructing a large-capacity and wide-interval frequency-hopping sequence set. Background Art

[0002] At present, from a narrow perspective, communication-restricted environments refer to environments with limited resources, harsh environments, and damaged infrastructure. These include areas where 4G / 5G base stations are difficult to deploy and wireless networks are difficult to cover; environments where communication interference is severe and normal communication is difficult to implement. Such as remote mountainous areas, virgin forests, uninhabited areas, etc.; disasters such as earthquakes and floods, and environments where communication facilities are severely destroyed. In order to ensure rescue and emergency assistance, it is necessary to comprehensively utilize various communication resources and establish an emergency communication system. To ensure the accurate transmission of information and the smooth progress of rescue, the emergency communication system must have efficient and reliable functions. Shortwave emergency communication is a key technology used by emergency communication systems, with the advantages of long-distance transmission capability, no reliance on ground relay stations or network hubs, rapid deployment, low operating cost, multi-scenario applicability, and real-time vehicle monitoring.

[0003] Frequency hopping is a key technology used by shortwave emergency communication ad hoc radio stations (ad hoc frequency hopping radio stations). It deploys a frequency hopping communication system through a frequency hopping module in an ad hoc frequency hopping radio station. Due to its flexible and rapid deployment, efficient data transmission, and all-weather communication, frequency hopping radio stations have become a key component in emergency communication systems. They perform frequency point changes based on pseudo-random frequency hopping sequences to achieve frequency diversity and interference resistance, effectively improving the transmission quality of wireless links and reducing the impact of interference on wireless transmission. In emergency communications, even if some frequencies are interfered with by natural or artificial interference such as lightning and electromagnetics, normal communication can still be carried out on other frequencies that are not interfered with. The communication is relatively concealed and it is difficult to intercept the communication content. The frequency intervals between two adjacent frequencies in a wide-interval frequency hopping sequence are unequal, which can further improve the efficiency, safety, and reliability of the emergency communication system.

[0004] At present, theoretical research on wide-interval frequency hopping sequence sets is a hot topic, and related construction methods have been proposed, such as processing the base sequence set, extending the sequence period, and constructing a long-period wide-interval frequency hopping sequence set; splicing several base sequences to construct a single long-period wide-interval frequency hopping sequence; constructing a wide-interval frequency hopping sequence set based on the polynomial representation of the frequency set; using the frequency hopping sequence as the base sequence, the construction method of the low-collision zone wide-interval frequency hopping sequence set and the construction method of the generalized collision-free zone wide-interval frequency hopping sequence set; the construction method of the narrow collision-free zone wide-interval frequency hopping sequence set based on the finite field; the construction method of the generalized collision-free zone wide-interval frequency hopping sequence set based on the Chinese remainder theorem.

[0005] However, although the wide-interval frequency-hopping sequence set generated by the existing construction method is optimal in some indicators, such as the optimal Hamming correlation, the number of sequences in the sequence set is relatively small, which will limit the frequency-hopping networking capability and user capacity in practical applications. Summary of the invention

[0006] Based on this, it is necessary to provide a method for constructing a large-capacity and wide-interval frequency hopping sequence set to address the above technical issues.

[0007] The present invention adopts the following technical solutions:

[0008] The present invention provides a method for constructing a large-capacity wide-interval frequency hopping sequence set, comprising:

[0009] The frequencies in the initial frequency set Q={0,1,2,...,q-1} in the frequency modulation communication process are arranged and combined to construct any non-overlapping sequence set or one-overlapping sequence set on the initial frequency set as a base sequence set; the number of sequences in the base sequence set is N, and the length of each sequence is L;

[0010] Select any k sequences from the base sequence set as candidate sequences. When the frequency of the t-th position of each candidate sequence is equal to the frequency of the t+1-th position, any candidate sequence is cyclically shifted left by one position or cyclically shifted right by one position, so that the frequency of the t-th position of each candidate sequence after processing is not equal to the frequency of the t+1-th position;

[0011] According to the processed candidate sequences, a frequency set F = {0, 1, 2, ..., q k -1} on a wide-interval frequency-hopping sequence S u =(s u (0),s u (1),...,s u (t),...,s u (L-1)), wide interval frequency hopping sequence S u The frequency of the t-th position in is:

[0012] Traverse all k sequences in the base sequence set to update the candidate sequence, and obtain N sequences through multiple rounds of construction. k A large capacity and wide interval frequency hopping sequence set of sequences for frequency hopping networking;

[0013] Where k>1, s u (t) is the wide interval frequency hopping sequence S u The frequency of the tth position in is the frequency of the tth position in the u0th sequence in the base sequence set.

[0014] Optionally, the selecting any k sequences from the base sequence set as candidate sequences specifically includes:

[0015] Select any k identical or different sequences from the base sequence set as candidate sequences by the following formula:

[0016] u=(u0,u1,...,u k-1 )∈{0,1,...,N-1} k ;

[0017] Wherein, u=(u0,u1,...,uk-1) represents the number set of the selected sequence, {0,1,...,N-1} k It represents an ordered k-tuple consisting of any k numbers selected from the set of all sequence numbers {0, 1, ..., N-1}, where k is a preset number.

[0018] Optionally, the large-capacity wide-interval frequency hopping sequence set is a large-capacity wide-interval frequency hopping sequence set with optimal Hamming correlation;

[0019] The method further comprises:

[0020] The interval between any two adjacent frequencies of each wide-interval frequency hopping sequence is determined by the following formula:

[0021]

[0022] According to communication requirements, a wide-interval frequency hopping sequence with a frequency interval greater than a preset frequency interval is selected from a large-capacity wide-interval frequency hopping sequence set for application;

[0023] Among them, d u,t,t+1 is the wide interval frequency hopping sequence S u The frequency interval between the frequency at the t-th position and the frequency at the t+1-th position.

[0024] At least one of the above technical solutions adopted by the present invention can achieve the following beneficial effects:

[0025] The present invention arranges and combines the frequencies in the initial frequency set Q = {0, 1, 2, ..., q-1}, constructs any non-overlapping or one-overlapping sequence set on the initial frequency set as a base sequence set, selects any k (k>1) sequences from the base sequence set as candidate sequences, and processes the candidate sequences so that the frequency of the t-th position of each candidate sequence after processing is not equal to the frequency of the t+1-th position, and then constructs a frequency set F = {0, 1, 2, ..., q-1} according to each processed candidate sequence. k -1}, in the process of traversing all k sequences in the base sequence set to update the candidate sequence, a wide interval frequency hopping sequence containing N can be obtained through multiple rounds of construction. kThe Hamming correlation of the large-capacity wide-interval frequency-hopping sequence set is optimal. In engineering applications, it can not only improve the anti-interference performance of the frequency-hopping communication system, but also increase the frequency-hopping networking capability and user capacity, providing technical support for a large number of application scenarios such as communication-restricted environments and high-security communication environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A schematic flow chart of a method for constructing a large-capacity wide-interval frequency hopping sequence set provided by the present invention;

[0028] Figure 2 A schematic diagram of the minimum frequency interval of each sequence in a large-capacity wide-interval frequency hopping sequence set S provided by the present invention;

[0029] Figure 3 A distribution diagram of adjacent frequency intervals of the sixth sequence in a large-capacity wide-interval frequency hopping sequence set S provided by the present invention;

[0030] Figure 4 A schematic diagram of the minimum frequency interval of each sequence in a large-capacity wide-interval frequency hopping sequence set S′ provided by the present invention;

[0031] Figure 5 A schematic diagram of the minimum frequency interval of the 359th sequence in a large-capacity wide-interval frequency hopping sequence set S′ provided by the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] Figure 1 The present invention is a flowchart of a method for constructing a wide-interval frequency hopping sequence set, which specifically includes the following steps:

[0035] S101: Arrange and combine the frequencies in an initial frequency set Q={0,1,2,...,q-1} in a frequency modulation communication process to construct any non-overlapping sequence set or one-overlapping sequence set on the initial frequency set as a base sequence set; the number of sequences in the base sequence set is N, and the length of each sequence is L.

[0036] S102: Select any k sequences from the base sequence set as candidate sequences. When the frequency of the t-th position of each candidate sequence is equal to the frequency of the t+1-th position, perform a cyclic left shift or a cyclic right shift on any candidate sequence so that the frequency of the t-th position of each candidate sequence after the processing is not equal to the frequency of the t+1-th position.

[0037] S103: construct a frequency set F={0,1,2,...,q k -1} on a wide-interval frequency-hopping sequence S u =(s u (0),s u (1),...,s u (t),...,s u (L-1)), wide interval frequency hopping sequence S u The frequency of the t-th position in is:

[0038] S104: Traverse all k sequences in the base sequence set to update the candidate sequence, and obtain N candidate sequences through multiple rounds of construction. k A large-capacity, wide-interval frequency hopping sequence set of sequences is used for frequency hopping networking.

[0039] For the convenience of explanation, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0040] In practical applications, we can first set the initial frequency set to Q = {0, 1, 2, ..., q-1}, and construct any non-overlapping sequence set or one-overlapping sequence set X = {x i =(x i (0),x i (1),,...,x i (L-1)),i=0,1,...,N-1} is the basis sequence set.

[0041] In the formula, q is the number of elements in the initial frequency set, X is the base sequence set, and x i is the i-th sequence, L is the sequence length, and N is the number of sequences in the base sequence set.

[0042] Then, let the preset number k>1, u=(u0,u1,...,u k-1 )∈{0,1,...,N-1} k, {0,1,...,N-1} k Indicates the selection of an ordered k-tuple consisting of any k numbers from the set of all sequence numbers {0,1,...,N-1}, indicating the selected candidate sequence The frequency distribution of each candidate sequence in Then you can Circularly shift left or right by one position. Of course, only Take this as an example to illustrate.

[0043] In the formula, u=(u0,u1,...,u k-1 ) represents the number set of the selected sequence, and k is a preset number.

[0044] Afterwards, based on the processed candidate sequence Construct a frequency set {0,1,2,...,q k -1} is a wide-interval frequency hopping sequence S u =(s u (0),s u (1),...,s u (L-1)), the frequency of the tth position is

[0045]

[0046] Among them, s u (t) represents the wide-interval frequency hopping sequence S u The frequency of the tth position in is the uth i The frequency of the t-th position in a sequence, t=0,...,L-1, i=0,...,k-1.

[0047] Let u=(u0,u1,...,u k-1 ) Take all the numbers in {0,1,...,N-1} k All k-tuples in , the frequency set {0,1,2,...,q k A large capacity interval frequency hopping sequence set on

[0048] In addition, suppose the wide-interval frequency hopping sequence S u The frequency of the t-th position and the frequency of the t+1-th position in are:

[0049] and

[0050]

[0051] The interval between any two adjacent frequencies of each wide-interval frequency hopping sequence can be determined by the following formula:

[0052]

[0053] Calculate the frequency intervals of all wide-interval frequency hopping sequences in the large-capacity wide-interval frequency hopping sequence set, and obtain the frequency interval value range of the wide-interval frequency hopping sequence set S 2≤d S ≤q k-1 According to the communication requirements, a wide-interval frequency hopping sequence with a frequency interval greater than a preset frequency interval can be selected from a large-capacity wide-interval frequency hopping sequence set for application. For example, a wide-interval frequency hopping sequence with a frequency interval greater than a given frequency interval of 5 can be selected.

[0054] based on Figure 1 The method for constructing a wide-interval frequency hopping sequence set shown in the figure first arranges and combines the frequencies in the initial frequency set Q = {0, 1, 2, ..., q-1}, constructs any non-overlapping or one-overlapping sequence set on the initial frequency set as a base sequence set, selects any k (k>1) sequences from the base sequence set as candidate sequences, and processes the candidate sequences so that the frequency of the t-th position of each processed candidate sequence is not equal to the frequency of the t+1-th position, and then constructs a frequency set F = {0, 1, 2, ..., q-1} according to each processed candidate sequence. k -1}, in the process of traversing all k sequences in the base sequence set to update the candidate sequence, a wide interval frequency hopping sequence containing N can be obtained through multiple rounds of construction. k The Hamming correlation of the large-capacity wide-interval frequency-hopping sequence set is optimal. In engineering applications, it can not only improve the anti-interference performance of the frequency-hopping communication system, but also increase the frequency-hopping networking capability and user capacity, providing technical support for a large number of application scenarios such as communication-restricted environments and high-security communication environments.

[0055] In addition, the present invention also provides two construction examples of a method for constructing a wide-interval frequency hopping sequence set:

[0056] 1. The case where adjacent frequencies are not equal: Assume that the frequency set of the frequency hopping communication bandwidth Q = {0, 1, 2, ..., 16}, and construct a non-repeating sequence set X on Q, as shown in Table 1.

[0057] Table 1 Base sequence set X

[0058]

[0059] It can be seen that the length of the base sequence set is 16 and the number of base sequences is 17. Take k = 2, u = (u0, u1) ∈ {0, 1, ..., 16} 2 , select the alternative sequence Construct a wide-interval frequency-hopping sequence S on F = {0, 1, 2, ..., 288} u =(s u (0),...,s u(15)), the frequency of the t-th position is Take all {0,1,...,16} 2 For all pairs in , similar operations can be performed to obtain a wide-interval frequency hopping sequence set S = {S (0,0) ,S (0,1) ,S (0,2) ,...,S (1,16)}, which contains 289 wide-interval frequency hopping sequences, as shown in Table 2.

[0060] Table 2 Wide interval frequency hopping sequence set S

[0061]

[0062] 2. When adjacent frequencies are equal: Take the frequency set Q = {0, 1, 2, ..., 19} of the frequency hopping communication bandwidth and construct a non-repeating sequence X′ on Q, as shown in Table 3.

[0063] Table 3 Base sequence set X′

[0064]

[0065] It can be seen that the sequence length of the base sequence set is 19, and the number of sequences in the base sequence set is 19. Take k = 2, u = (u0, u1) ∈ {0, 1, ..., 18} 2 , there are cases where adjacent frequencies in X′ are equal, select the alternative sequence Then Circularly shift left by one bit to construct a wide interval frequency hopping sequence S on F = {0,...,360} u ′=(s u ′(0),...,s u ′(18)), the frequency of the t-th position is Finally, we get a wide interval frequency hopping sequence set S′={S′ (0,0) ,S′ (0,1) ,S′ (0,2) ,...,S′ (1,18)}, which contains 381 wide-interval frequency hopping sequences, as shown in Table 4.

[0066] Table 4 Wide interval frequency hopping sequence set S′

[0067]

[0068] The maximum Hamming correlation value of S and S′ is 1, which has the best Hamming correlation characteristic; it has excellent wide interval characteristics, and the minimum frequency interval of each wide interval frequency hopping sequence in S and S′ is as follows: Figure 2 And such as Figure 4As shown in Figure 2, the adjacent frequency intervals of each wide-interval frequency hopping sequence in S and S′ are almost randomly distributed. Select a sequence and calculate its adjacent frequency intervals. The distribution is shown in Figure 2. Figure 3 And such as Figure 5 As shown, the adjacent frequency intervals of other arbitrary wide-interval frequency hopping sequences have similar distributions. The sequence set generated by the construction method of the large-capacity wide-interval frequency hopping sequence set proposed by the present invention not only has a large number of sequences, but also has the optimal Hamming correlation characteristics and good wide-interval characteristics, while improving the anti-interference performance of the frequency hopping communication system, it also increases the user capacity of the frequency hopping networking capability set.

[0069] The above is a method for constructing a large-capacity wide-interval frequency hopping sequence set provided by one or more embodiments of the present invention. The above embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for constructing a large-capacity wide-interval frequency hopping sequence set, characterized in that: include: The frequencies in the initial frequency set Q={0,1,2,...,q-1} in the frequency modulation communication process are arranged and combined to construct any non-overlapping sequence set or one-overlapping sequence set on the initial frequency set as a base sequence set; the number of sequences in the base sequence set is N, and the length of each sequence is L; Select any k sequences from the base sequence set as candidate sequences. When the frequency of the t-th position of each candidate sequence is equal to the frequency of the t+1-th position, any candidate sequence is cyclically shifted left by one position or cyclically shifted right by one position, so that the frequency of the t-th position of each candidate sequence after processing is not equal to the frequency of the t+1-th position; According to the processed candidate sequence, a frequency set F = {0, 1, 2, ..., q k -1} on a wide-interval frequency-hopping sequence S u =(s u (0),s u (1),...,s u (t),...,s u (L-1)), wide interval frequency hopping sequence S u The frequency of the t-th position in is: Traverse all k sequences in the base sequence set to update the candidate sequence, and obtain N sequences through multiple rounds of construction. k A large capacity and wide interval frequency hopping sequence set of sequences for frequency hopping networking; Where k>1, s u (t) is the wide interval frequency hopping sequence S u The frequency of the tth position in is the frequency of the tth position in the u0th sequence in the base sequence set.

2. The method for constructing a large-capacity wide-interval frequency hopping sequence set according to claim 1, characterized in that: The selecting any k sequences from the base sequence set as candidate sequences specifically includes: Select any k identical or different sequences from the base sequence set as candidate sequences by the following formula: u=(u0,u1,...,u k-1 )∈{0,1,...,N-1} k ; Wherein, u=(u0,u1,...,uk-1) represents the number set of the selected sequence, {0,1,...,N-1} k It represents an ordered k-tuple consisting of any k numbers selected from the set of all sequence numbers {0, 1, ..., N-1}, where k is a preset number.

3. The method for constructing a large-capacity wide-interval frequency hopping sequence set according to claim 1, characterized in that: The large-capacity wide-interval frequency hopping sequence set is a large-capacity wide-interval frequency hopping sequence set with optimal Hamming correlation; The method further comprises: The interval between any two adjacent frequencies of each wide-interval frequency hopping sequence is determined by the following formula: According to communication requirements, a wide-interval frequency hopping sequence with a frequency interval greater than a preset frequency interval is selected from a large-capacity wide-interval frequency hopping sequence set for application; Among them, d u,t,t+1 is the wide interval frequency hopping sequence S u The frequency interval between the frequency at the t-th position and the frequency at the t+1-th position.

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