Background technology
Due to the development of China's sustain economic fast and stable, cause urban construction and the demand rapid growth of life to electric power, the transformer station of a large amount of voltage levels and electrical network have been built or have been built, and current electromagnetic environment is become increasingly complex.The focus of 21 century war will concentrate on how to obtain information needed quickly and accurately, and how to deprive the useful information of enemy, Information Superiority has become the key factor determining war face-off both sides victory or defeat, and ensure efficiently, information transmission is smoothly comprehensive various operation key element, the key link playing fullfledged combat capability.Material is thus formed new key element---the Complicated Electromagnetic Environment in Battlefield being different from traditional battlefield.Under such battlefield surroundings, information-based and combined operation have developed into a kind of brand-new mode of operation.Combined operation under Information Condition, the various scouting detection systems be distributed on the space war battlefield of land, sea and air, command and control system and attack weapon system (comprising offensive electronic warfare system) is required organically to combine, form a unification, efficiently combat system-of-systems, decision superiority and operation advantage is reached by capturing Information Superiority, realize the shared resources of situation of battlefield perception, operation hight coordinate with collaborative, greatly could improve fighting efficiency.But, there is lance to have shield, in the process of contention Information Superiority, due to the use of a large amount of electronic information equipment, they are substantial amounts, system complexity, wide variety not only, and power is large, make the electromagnetic signal very dense in space, battlefield, define very complicated electromagnetic environment.
So-called complex electromagnetic environment, refer to polymorphic type, entire spectrum, highdensity ELECTROMAGNETIC RADIATION SIGNATURE that Information Battlefield produces under the fierce Resisting Condition of both sides at war, and one's own side use electronic equipment to cause in a large number influencing each other and disturbing, thus cause crowded overlap on crisscross on changeable, the spatial domain of happening suddenly in time domain, frequency domain, have a strong impact on the invisible battlefield surroundings of effectiveness of weapon equipment, operational commanding and troop operation action.
In order to improve the survival ability under complex electromagnetic environment, how research utilizes advanced Digital Signal Processing, improves or strengthens the antijamming capability of existing communication system, especially improves the jamming pattern that those conventional Anti-Jamming Technique measures can not resist and obviously have its necessity, importance and urgency.
Along with the develop rapidly of the communication technology, business demand also constantly increases.Which results in the contradiction between the growth of traffic demands and limited frequency spectrum resource, make frequency spectrum resource more and more nervous.From communication countermeasures angle, the crowded limited available bandwidth meaning each communication system of frequency band, so must cause the difficulty resisting Communication Jamming to strengthen.Especially for spread spectrum communication, its frequency band for raising signal to noise ratio institute broadening also also exists following shortcoming: one, it can not make full use of the anti-interference potentiality adding broadband and bring, when signal to noise ratio is very low in fact at the frequency spectrum resource that " waste " is valuable; Its two, after occupying wide frequency band, the user that same minizone communicates simultaneously is not one but multiple, under the environment of multipath fading, inevitably causes serious intersymbol interference.In limited frequency spectrum resource, realize antijam communication, just utilize frequency spectrum resource, arrowband Anti-Jamming Technique proposes new higher requirement.Second needs the problem solved to be that the impact of white Gaussian noise interference signal on channel is larger, and is not easy in the ordinary course of things to remove.So-called white Gaussian noise interference signal be exactly the amplitude distribution Gaussian distributed of interference signal, and its power spectral density is equally distributed.Frequency band due to white Gaussian noise interference signal is very wide almost occupies whole field, and it is overlapping with signal of communication cannot distinguish useful signal and interference signal, uses above-mentioned frequency hopping and spread spectrum just can not reach gratifying effect.
Summary of the invention
The invention provides a kind of method realizing frequency hopping communications and networking under strong electromagnetic interference environment to solve the problems of the technologies described above, object improves the reliability of communication system and validity makes it adapt to strong electromagnetic complex environment.
For reaching a kind of method realizing frequency hopping communications under strong electromagnetic interference environment of above-mentioned purpose the present invention, step is as follows:
(1) foundation of frequency-hopping system Mathematical Modeling, by carrying out baseband modulation to input information code sequence, then making debit synchronous with originating party by the control of frequency hop sequences controller, completing reception and the transmission of Frequency Hopping Signal;
(2) foundation of frequency-hopping synchronization, allows frequency-hopping receiver use identical frequency with frequency hopping transmitter in the identical moment, obtains correct IF-FRE;
(3) determination of frequency hopping pattern, is designed by the frequency hopping pattern based on RS code, choosing coefficient in galois field, then converts;
(4) networking of frequency hopping communications, and then the coverage in expansion radio station carries out networking.
In step (1), transmitting terminal information data is by after waveform transformation, and incoming carrier is modulated, and carrier wave controls variable frequency synthesizer by FH Sequence Generator and produces, and frequency hop sequences value changes once, and carrier frequency changes once, the wide T of code element of frequency hop sequences
c, then at interval of time T
c, carrier frequency saltus step once, the carrier wave produced by FH Sequence Generator control frequency synthesizer like this and information data carry out carrier modulation, and then remove low frequency signal through high pass filter, signal out carries out launching receiving end through radio-frequency filter again from high pass filter later and receives, at receiving terminal, the signal received is first through a broadband filter, in order to ensure the synchronous of debit and originating party signal, the local oscillation signal of receiver is also a frequency hopped signals, saltus step rule is by the control of the pseudo noise code of receiving terminal, and the pseudo noise code of receiving terminal generation and the identical of transmitting terminal, the rule of control frequency change is identical, the frequency of two frequency synthesizer generations is corresponding, but the frequency of correspondence has a frequency difference f
i, be just in time the intermediate frequency of receiver, as long as the pseudo noise code of receiving-transmitting sides is synchronous, the jump frequency that just frequency synthesizer of receiving-transmitting sides can be made to produce is synchronous, after a band pass filter, just can obtain a changeless intermediate-freuqncy signal, then this intermediate-freuqncy signal carries out demodulation through a data demodulator, just can recover the information sent, so far complete transmission and the reception of Frequency Hopping Signal.
In step (2), carry out in synchronous process debit, recipient is in slow scanning state once starting shooting, frequency hopping is carried out with the speed lower than chirp rate, to catch the synchronizing information in targeting sequencing, if do not capture synchronizing information, proceed slow scanning and repeat above-mentioned steps again, if the synchronizing information of capturing, then determine whether targeting sequencing further, if targeting sequencing is then proofreaded lock in time and is carried out with jumping, otherwise enter and enter net state late, then targeting sequencing is reaffirmed after having proofreaded lock in time, if targeting sequencing then carries out reception network No. and temporal information, if be not also targeting sequencing, get back to initial slow scanning state, finally complete synchronous foundation.
In step (3), to the design process of frequency hopping pattern be: (1) input galois field generator polynomial coefficient, the power m in territory, and the value of c1, c0; Unit in galois field have three kinds of method for expressing, for GF (2
3) on, the multinomial of generation is f (x)=x
3+ x+1 α=2=(010), for galois field α=2=(010), like this by territory 2
3=8 elements three kinds of diverse ways show, and obtain α
nbe α
n-1carry out moving to left one, and when the left side highest order of vector is 1, then m-1 item before the vector after moving to left, the coefficient module two of the power corresponding with generator polynomial adds, and obtains the coefficient of Jia Luohua like this; (2) period p of the sequence of calculation; (3) call subfunction, convert the value of c1 to power by the decimal system and represent, and then the power of c1 is represented the power matirx cxm with the element multiplication output multiplication result in territory; (4) whether coefficient of determination c0 is 0, if be 0, convert the power in matrix cxm to decimal number, finally exports, if coefficient is not 0, then convert c0 and matrix cxm to 2 yuan, m position vector C 0-w, cxw, convert each component phase adduction of c0-w, cxw to the decimal system again; (5) improvement of code generator polynomial, in order to solve asynchronous networking, the problem that between any two sequences, Hamming cross-correlation secondary lobe increases sharply, improves generator polynomial, below by sequence { p
jeach code bit element add a fixed amount { α
2j, obtain
multinomial; If another sequence { q
jmultinomial by Q (α
sx)=(α
sx)
2+ C
0+ C
1α
sthis multinomial of x produces, then the difference of P (x) and Q (x) is expressed as P (x)-Q (α
sx)=(1-α
2s) x
2+ C
1(1-α
s) x, because α
sin s can choose arbitrarily, so opening code position between two sequences between maximum consistent code bit number and two sequences has nothing to do, may be used for asynchronous frequency hopping communications networks.
In step (4), there are 8 operating states in frequency hopping communications radio station, comprise scanning mode, calling arrange state, send call state, frequency fixing communication state, late network application status, receive slow networking application information state, send slow networking boot state and frequency hopping communications state, comprising:
A) status scan: before networking, in net, all frequency hopping radio sets are all in scanning mode, by the state residing for status scan determination frequency hopping radio set;
B) first calling procedure: frequency hopping communications can be divided into three steps in the process of networking is that frequency hopping net is exhaled, and a radio station is by arranging all radio station in calling Home Network or other nets exactly, realizes the radio station in calling one net; Next is frequency hopping selective call, and another radio station, in Home Network, by arranging the call object in Home Network, is called out in radio station, a certain portion; Be finally determine frequency calling, frequency hopping radio set, by arranging fixing operating frequency, is operated in frequency fixing communication state, on the selected channel with determine frequency radio station and communicate;
C) network process is entered late: when oneself is in frequency hopping communications state when other radio station in netting, fail to network for a certain reason in one or multi-section radio station, need to take certain measure to enter frequency hopping communications networks operating state, at this moment radio station will enter the application status that networks late, then enter and receive the application status that networks late, transmission will be entered to network late boot state once receive application, finally enter frequency hopping communications state.
Advantageous effect of the present invention: the error rate of system can be reduced thus the overall performance of elevator system.Improve the antijamming capability of communication, particularly under the circumstances of battlefield communications of complexity, improve the confidentiality of communication and the reliability of transmission, and frequency hopping communications can utilize different frequency hopping patterns to receive multiple frequency-hopping system at certain broadband content to work simultaneously, thus greatly improve system spectrum utilance.
Embodiment
In order to make object of the present invention, technical scheme and beneficial effect clearly understand, below in conjunction with accompanying drawing, the present invention is described in further detail.
Under strong electromagnetic interference environment, realize a method for frequency hopping communications, step is as follows:
(1) foundation of frequency-hopping system Mathematical Modeling, by carrying out baseband modulation to input information code sequence, then making debit synchronous with originating party by the control of frequency hop sequences controller, completing reception and the transmission of Frequency Hopping Signal;
(2) foundation of frequency-hopping synchronization, allows frequency-hopping receiver use identical frequency with frequency hopping transmitter in the identical moment, obtains correct IF-FRE;
(3) determination of frequency hopping pattern, is designed by the frequency hopping pattern based on RS code, choosing coefficient in galois field, then converts;
(4) networking of frequency hopping communications, and then the coverage in expansion radio station carries out networking.
In step (1), transmitting terminal information data is by after waveform transformation, and incoming carrier is modulated, and carrier wave controls variable frequency synthesizer by FH Sequence Generator and produces, and frequency hop sequences value changes once, and carrier frequency changes once, the wide T of code element of frequency hop sequences
c, then at interval of time T
c, carrier frequency saltus step once, the carrier wave produced by FH Sequence Generator control frequency synthesizer like this and information data carry out carrier modulation, and then remove low frequency signal through high pass filter, signal out carries out launching receiving end through radio-frequency filter again from high pass filter later and receives, at receiving terminal, the signal received is first through a broadband filter, in order to ensure the synchronous of debit and originating party signal, the local oscillation signal of receiver is also a frequency hopped signals, saltus step rule is by the control of the pseudo noise code of receiving terminal, and the pseudo noise code of receiving terminal generation and the identical of transmitting terminal, the rule of control frequency change is identical, the frequency of two frequency synthesizer generations is corresponding, but the frequency of correspondence has a frequency difference f
i, be just in time the intermediate frequency of receiver, as long as the pseudo noise code of receiving-transmitting sides is synchronous, the jump frequency that just frequency synthesizer of receiving-transmitting sides can be made to produce is synchronous, after a band pass filter, just can obtain a changeless intermediate-freuqncy signal, then this intermediate-freuqncy signal carries out demodulation through a data demodulator, just can recover the information sent, so far complete transmission and the reception of Frequency Hopping Signal.
In step (2), carry out in synchronous process debit, recipient is in slow scanning state once starting shooting, frequency hopping is carried out with the speed lower than chirp rate, to catch the synchronizing information in targeting sequencing, if do not capture synchronizing information, proceed slow scanning and repeat above-mentioned steps again, if the synchronizing information of capturing, then determine whether targeting sequencing further, if targeting sequencing is then proofreaded lock in time and is carried out with jumping, otherwise enter and enter net state late, then targeting sequencing is reaffirmed after having proofreaded lock in time, if targeting sequencing then carries out reception network No. and temporal information, if be not also targeting sequencing, get back to initial slow scanning state, finally complete synchronous foundation.
In step (3), to the design process of frequency hopping pattern be: (1) input galois field generator polynomial coefficient, the power m in territory, and the value of c1, c0; Unit in galois field have three kinds of method for expressing, for GF (2
3) on, the multinomial of generation is f (x)=x
3+ x+1 α=2=(010), for galois field α=2=(010), like this by territory 2
3=8 elements three kinds of diverse ways show, and obtain α
nbe α
n-1carry out moving to left one, and when the left side highest order of vector is 1, then m-1 item before the vector after moving to left, the coefficient module two of the power corresponding with generator polynomial adds, and obtains the coefficient of Jia Luohua like this; (2) period p of the sequence of calculation; (3) call subfunction, convert the value of c1 to power by the decimal system and represent, and then the power of c1 is represented the power matirx cxm with the element multiplication output multiplication result in territory; (4) whether coefficient of determination c0 is 0, if be 0, convert the power in matrix cxm to decimal number, finally exports, if coefficient is not 0, then convert c0 and matrix cxm to 2 yuan, m position vector C 0-w, cxw, convert each component phase adduction of c0-w, cxw to the decimal system again; (5) improvement of code generator polynomial, in order to solve asynchronous networking, the problem that between any two sequences, Hamming cross-correlation secondary lobe increases sharply, improves generator polynomial, below by sequence { p
jeach code bit element add a fixed amount { α
2j, obtain
multinomial; If another sequence { q
jmultinomial by Q (α
sx)=(α
sx)
2+ C
0+ C
1α
sthis multinomial of x produces, then the difference of P (x) and Q (x) is expressed as P (x)-Q (α
sx)=(1-α
2s) x
2+ C
1(1-α
s) x, because α
sin s can choose arbitrarily, so opening code position between two sequences between maximum consistent code bit number and two sequences has nothing to do, may be used for asynchronous frequency hopping communications networks.
In step (4), there are 8 operating states in frequency hopping communications radio station, comprise scanning mode, calling arrange state, send call state, frequency fixing communication state, late network application status, receive slow networking application information state, send slow networking boot state and frequency hopping communications state, comprising:
At scanning mode, if certain radio station not yet networks, application networks late, thus enters the application status that networks late, after the application that networks late, automatically returns to scanning mode.At scanning mode, receive and the net of Home Network exhaled or to after the selective call of this TV station, automatically enters frequency hopping communications state.At scanning mode, other radio station be called out, if oneself completes setting, if directly call thus enter transmission call state and do not complete setting, then enter calling and state is set, after being provided with, then get back to scanning mode, if call out other radio station, enter transmission call state.After sending calling, entering frequency hopping communications state, being communicated with exhaling radio station.In frequency hopping communications state, if receive applying for as netted late of other radio station, then while continuation keeps frequency hopping communications, send the guidance information that networks late.If receive determine frequency radio station determine frequency calling, operator then can determine to carry out frequency fixing communication, while maintenance frequency-hopping synchronization, proceeds to and determines frequency channel and communicate with fixed frequency radio station, after having communicated, get back to frequency hopping communications state.After frequency hopping communications completes or among frequency hopping communications process, application enters scanning, then get back to scanning mode.In order to make radio station only search sweep in Home Network in net, in net, each radio station need arrange calling parameter before networking.Like this, just enter frequency hopping communications state when radio station only listens to Home Network or this TV station calling in net, that is, belong to platform only synchronous with main of calling out Home Network network No..Before networking, in net, all frequency hopping radio sets are all in scanning mode, when pressing transmit-receive switch for main, first main send synchronizing signal, this synchronizing signal netted in other belongs to after platform correctly receives, each genus platform first automatic calibration this TV station clock, then the frequency hopping rate of oneself is traced on the frequency hopping rate of main automatically, then set up frequency hopping communications.Communicate complete, in net, scanning mode is got back to again in all radio station, communicates to wait for next time.
The calling of frequency hopping radio set is divided into that following three kinds of mode frequency hopping nets are exhaled, frequency hopping selective call, fixed calling frequently.
(1), frequency hopping net is exhaled: all radio station referred in a calling-up Home Network or other nets exhaled by frequency hopping net, realize frequency hopping communications.When certain frequency hopping radio set carry out net exhale time, every other radio station with this radio station with identical Hopping frequencies table, cipher key number, network No., all radio station namely in same subnet, all can respond net and exhale signal.
(2), frequency hopping selective call: frequency hopping selective call refers to another radio station, in a certain portion calling-up Home Network, realizes frequency hopping communications.Radio station selective call is in another radio station, in same subnet, calls out as long as directly choose by page station number and send.Radio station can not selective call two not radio station on the same stage number simultaneously.
(3), fixed calling frequently: frequency hopping radio set can be operated in frequency fixing communication state, on the selected channel with determine frequency radio station and communicate.The frequency calling frequency of determining of fixed radio station frequently agreement sends calling to frequency hopping radio set, frequency hopping radio set is windowed at this fixed calling frequency frequently, operator's pressing " surely exhaling " key proceeds to be determined frequency channel and communicates with fixed radio station frequently, and after communication, pressing " surely exhaling " key returns former frequency hopping net again.
When slow networking refers to that oneself is in frequency hopping communications state when other radio station in netting, networking is failed in one or multi-section radio station for a certain reason, needs to take certain measure to enter a kind of network access mode of frequency hopping communications networks work.Slow networking is mainly divided into three kinds of network access modes, and initiatively application networks late, passive traction networks late and duties synchronously network late.
(1) initiatively application networks late: initiatively application networks late and refers to that the radio station not entering work in frequency hopping communications networks initiatively sends the application that networks, then sends the network access mode of slow networking pilot signal by radio station in net.The course of work that initiatively application networks late is divided into four-stage to send the slow networking application information stage, receives the slow networking application information stage, sends the slow networking guidance information stage, networks late and set up state phase.
(2) passive traction networks late: passive traction networks late and refers to that in net, radio station finds that there is by roll-call mode the radio station that do not network after networking, by the function that networks late, guides the radio station that do not network to enter the slow network access mode of one of communication network.The course of work is in scanning mode for the radio station that do not network, and in net, radio station is under frequency hopping communications state, and direct transmission networks pilot signal late, and the radio station that do not network is pulled and enters frequency hopping communications networks.
(3) duties synchronously network late: duties synchronously network late and refer to the radio station neither initiatively application that do not network, and in net, radio station names no names again, but by receiving the slow network access mode of one that the duties synchronizing information inserted in frequcny modulation data stream realizes networking late.The course of work is that in all nets, radio station, in normal frequency hopping communications process, often at regular intervals, predetermined duties frequency sends duties synchronizing information, and the duties synchronizing information inserted in frequency-hopped data stream is searched in the radio station that do not network in predetermined duties frequency.Do not network after radio station receives all required synchronizing informations, adjustment real-time clock, just achieves slow networking.
Under strong electromagnetic environment, the interference of more complicated in communication system, can be produced, the hybrid technology that common Anti-Jamming Technique has spread spectrum, intelligent antenna technology and multiple technologies to combine.Frequency hopping is one of the most frequently used spread spectrum mode, its operation principle refers to that the carrier frequency of receiving-transmitting sides signal transmission carries out the communication mode of Discrete Change according to predetermined rule, and the carrier frequency that is used in communication is random jump by the control of pseudorandom change code.Time domain, Frequency Hopping Signal is a multifrequency frequency shift keyed signals; From frequency domain, the frequency spectrum of Frequency Hopping Signal be one in very broadband with unequal interval random jump.Compared with directly-enlarging system, the pseudo random sequence in frequency-hopping system does not directly transmit, and is used to selective channel.
In the modelling process of frequency hopping communications, we introduce following Mathematical Modeling, and at the transmitting terminal of system, carry out baseband modulation to input information code sequence and obtain modulation signal m (t), its frequency bandwidth is B
m.The pseudo-random code sequence that FH Sequence Generator independently produces removes control frequency synthesizer as frequency hop sequences, makes its output frequency by the change of different frequency hopping patterns or instruction random skip.Modulation signal m (t) is modulated random carrier, obtains Frequency Hopping Signal S
i(t), this class signal is similar to carrier (boc) modulated signals, can be expressed as with mathematical formulae:
in this formula, ω
0+ n ω
△with
for at nT
c≤ t< (n+1) T
cthe frequency that the time interval transmits and first phase, ω
△for Hopping frequencies interval.Frequency-hopping system is by different conversion, and final output signal is S (t), is formulated as: S (t)=S
i(t)+J (t)+n (t).At receiving terminal, in order to input signal demodulation, need the frequency hopping instruction generated with identical local pseudo-code generator of making a start to go to control local frequency synthesizer, the local oscillation signal frequency making it export is with the corresponding saltus step of originating party frequency, the local oscillation signal of saltus step carries out frequency conversion to the Frequency Hopping Signal received, again by low pass filter, realize separating and jump, obtain modulation signal m (t).After low pass filter, can obtain
The design that frequency-hopping system is synchronous, frequency-hopping synchronization refers to that frequency-hopping receiver uses identical frequency with frequency hopping transmitter in the identical moment.The frequency that the frequency of such Received signal strength and local frequency synthesizer produce just can obtain correct IF-FRE after mixing, then therefrom demodulates information signal, otherwise correctly can not demodulate information signal.Digital frequency-hop system refers to the frequency-hopping communication system transmitting digital voice or data.Therefore, it transmits hopping synchronization information is carry out with the form of Frame.Digital system frequency hopping synchronization method nothing more than synchronous prefix method, self-synchronizing method and reference clock method.Synchronous prefix method.To make a start the code word that need send containing synchronizing information, after receiving terminal decoding, according to synchronizing information make the local frequency hopper of receiving end with make a start synchronous.Synchronizing information, except bit synchronization, frame synchronization, mainly should comprise the real time status information of frequency hopping pattern or real-time clock information, i.e. so-called " TOD " information (TimeoftheDay).Real time clock information comprises date Hour Minute Second, millisecond, microsecond, nanosecond etc.; State information refers to the code sequence state that pseudo-code generator is real-time.According to these information, receiving end just can know that what frequency the frequency of current frequency hopping residence time and down hop residence time should be in, thus makes sending and receiving end frequency hopper synchronous working.In order to ensure the correct reception of TOD information, in synchronizing information data frame format as shown in the figure, bit synchronization and frame lock bit are housed.In addition, can adopt error-control technique to TOD information bit, as error correction coding, correlative coding or employing majority decision, to improve the reliability of transmission.
The design of frequency hopping pattern, so-called frequency hopping is exactly the rule of carrier wave saltus step.When Frequency Hopping Communication Networks mode is identical, designs a good frequency hopping pattern and can greatly reduce frequency hopping code collision.The design major design of Families of Frequency-Hopping Sequences is to 5 parameters; Frequency number q, sequence length L, sequence number N, Hamming correlation H and frequency interval d.These parameters retrain mutually, by the analysis to these parameters, can design comparatively ideal Families of Frequency-Hopping Sequences.If each frequency occurs once at most in a sequence period, then this sequence is called non repetitive sequence.The design of frequency hopping pattern is actually the select permeability of pseudo-code pattern.In order to the frequency hopping pattern obtained, have following requirement to pseudo noise code: 1, under different translation, the coincidence number between each code is little, in hop period, average coincidence number is little, and this just requires that the their cross correlation of code will be got well; 2, the coincidence number of each yard of sequence and oneself translation is little, and this just requires that the autocorrelation performance of code will be got well; 3, operational code sequence quantity wants many, and first this quantity will meet the requirement of the frequency hopping communications number of users using same frequency range, and wish that its quantity is the more the better, to meet the requirement of confidentiality.The kind of frequency hopping pattern generally refers to pseudo noise code as frequency hopping pattern control code and control method, at present, with more pseudo noise code mainly m sequence, M sequence and R-S code sequence.M sequence is the control code that frequency hopping pattern is conventional, and it easily produces, but from the viewpoint of maintaining secrecy, this frequency hopping pattern is with having weak point in a communications system, because when adopting computer simulation, it can be found very soon regular, and the size of key of m sequence is large not.M sequence number is more much more than m sequence, and be non-linear shift register sequence, can produce a lot of frequency hopping patterns, confidentiality is also strong.R-S code is a kind of nearly orthogonal code of the best, and number of users is many, easily realizes, and is a kind of desirable frequency hopping control code.