CN106332068A - Safety communication method of wireless sensor network of lightweight class heterogeneous radio frequency parameters - Google Patents

Abstract

The invention discloses a safety communication method of wireless sensor network of lightweight class heterogeneous radio frequency parameters, which generates jump pattern by combining false random sequence, to realize 3D change of three radio frequency parameters of joint bit rate, channel frequency and modulation way. The method is characterized by (1) preventing malicious interference attach of single channel through jump change of channel frequency; (2) introducing jump change of bit rate and modulation in jump change of channel frequency, to change retention time of signals and time sequence wave form, which greatly improves incoherence between signal wave form and frequency spectrum and adds price of tracking interference and invading wireless network, and effectively prevents attack of intermediary; and (3) lightweight class, able to distributively operate in each node of the wireless sensor network.

Description

A kind of wireless sense network safety communicating method of lightweight isomery radio frequency parameter saltus step

Technical field

The present invention relates to the secure communications of radio sensing network, particularly a kind of lightweight isomery radio frequency parameter saltus step Wireless sense network safety communicating method.

Background technology

Along with wireless communication technology and the fast development of electronics technologies, low cost, low-power consumption, multi-functional wireless biography The exploitation of sensor and extensively application are possibly realized.Yet with sensor node resource space and the restriction of power consumption, wireless sensing Net, in the case of multi-hop ad hoc, is faced with many security threats, and radio sensing network is except to consider in cable network Beyond the safety problem existed, also have many new safety problems, as a example by the common attack in wireless sense network.Mainly There is following two to attack:

1) malicious interference is attacked

Malicious node broadcast data packet in the channel, causes network congestion, normal node cannot route selection, thus node Between cannot be carried out communicating normally.

2) man-in-the-middle attack

In wireless communications, node uses, with node communication, the wireless channel shared, and malicious node can be monitored and distort Content of Communication.

Research shows the basic reason that above-mentioned attack exists: the feature of sensor network self multi-hop communication mode makes nothing Line sensing network is easily attacked by signal disturbing and invasion etc..Assailant utilizes shared wireless channel, can be in the wireless network Monitor channel, to attack meanses such as channels transmit bit stream, the packets listened to before resetting.

Existing research uses speed change frequency hopping communications, authentication and the defensive measure etc. on some upper stratas for invasion and interference Defending invasion and interference, this is improved by the present invention, has combined that channel frequency, bit rate and modulation system are multiple penetrates Frequently parameter resists invasion and interference, adds the non-correlation between signal waveform, simultaneously by pseudo-random sequence randomization, The three-dimensional hopping patterns making channel frequency, bit rate and modulation system composition is more complicated, various and random, greatly carries The high anti-intrusion of radio sensing network, capacity of resisting disturbance.

In actual radio communication, wireless sensor network to be invaded, it is necessary first to catch wireless signal, then analyze nothing The various agreements used in line communication, reduction Content of Communication, thus find out leak, implement invasion.And use combined channel frequency, Bit rate, modulation system radio frequency multiparameter saltus step communicate compared to traditional wireless communications method, can strengthen seizure and The difficulty of recovering signal.Owing in communication process, channel frequency, bit rate and modulation system all there occurs saltus step, invader needs To use different bit rates and modulation system to remove sniff wireless signal at multiple channel frequencies, just can capture signal.With Time invader to analyze the communication protocol of whole network, in addition it is also necessary to substantial amounts of sampling, to analyze the rule of saltus step in communication process Rule, just can trace into signal of communication.

Summary of the invention

The technical problem to be solved is, not enough for prior art, it is provided that a kind of lightweight isomery radio frequency ginseng The wireless sense network safety communicating method of number saltus step.

For solving above-mentioned technical problem, the technical solution adopted in the present invention is: a kind of lightweight isomery radio frequency parameter is jumped The wireless sense network safety communicating method become, comprises the following steps:

1) the channel frequency set F={f that hopping sequences is corresponding is generated_i| i=1,2 ... X}, f_iFor in channel frequency set I-th

Individual channel frequency；Generate the bit rate set R={r that hopping sequences is corresponding_j| j=1,2 ... Y}, r_jFor bit Speed

Jth bit rate in rate set；Generate the modulation system set M={m that hopping sequences is corresponding_k| k=1,2 ... Z}, m_kFor kth modulation system in modulation system set；

2) channel frequency, bit rate and modulation system being carried out random combine, the radio frequency parameter that total C kind is different is joined Put, obtain isomery radio frequency ternary argument sequence set, be abbreviated as G{f_i,r_j,m_k, the computing formula of C is: C=C_F×C_R×C_M, WhereinThe possible quantity selected for channel frequency；Select for the bit rate that residence time length is relevant Possible quantity；The possible quantity selected for modulation system；In conjunction with pseudo-random sequence to obtained ternary argument sequence collection Close G{f_i,r_j,m_kInner parameter point carries out selecting control, thus generates random isomery radio frequency parameter hopping patterns sequence, letter It is designated as G ' { f_i,r_j,m_k}；

3) the isomery radio frequency parameter hopping patterns sequence G ' { f that will have generated_i,r_j,m_kIt is provided in receiving-transmitting sides, and pass through Synchronous method, makes transmitting-receiving communication two ends saltus step initial time synchronize；

4) receiving-transmitting sides is according to isomery radio frequency parameter hopping patterns sequence G ' { f_i,r_j,m_kOrder carry out parameter switching, Arranging enumerator n initial value is 1, if sequence G ' { f_i,r_j,m_kInitial configuration radio frequency parameter is g₁, it is expressed as hopping patterns sequence G ' {f_i,r_j,m_kFirst example, g in }₂It is expressed as hopping patterns sequence G ' { f_i,r_j,m_kSecond example, g in }_nIt is expressed as saltus step Pattern sequence G ' { f_i,r_j,m_kN-th example in }, the rest may be inferred；Wherein 1≤n≤c；Receiving-transmitting sides arranges next saltus step switching Time timer；

5) when saltus step intervalometer switching time triggers, enumerator n adds 1, configures radio frequency parameter g_nIf, n≤C, start Next saltus step intervalometer switching time, goes to step 5)；If n is ＞ C, the most whole hopping patterns all travels through complete, goes to step 4), receive Send out both sides again from isomery radio frequency parameter g₁Start.

Receiving-transmitting sides arranges the process of next saltus step intervalometer switching time: if under continuous data transmission mode, After often carrying out primary parameter switching, according to parameter bits speed r in current ternary argument sequence set, transmission packet is Long length l_max, calculate current residence time t=l_max/ r, arranging next saltus step timer value switching time is that t+ Δ t, Δ t are The switch protecting time；If under cycle data transfer pattern, receiving-transmitting sides triggers according to sampling period T simultaneously and arranges down hop Becoming intervalometer switching time, next saltus step timer interval switching time time is T；T ＞ ＞ l_max/r_min, r_minFor minimum bit Speed.

In existing Frequency-hopping Communication Technology, radiofrequency signal typically uses single transfer rate and modulation system, therefore, often The aerial residence time of bit radiofrequency signal is identical, and signal waveform degree of association is high so that signal is readily identified after being trapped, decoding.

Realize changing the function of channel by changing communication frequency, increase the Tracking Jam difficulty to signal capture.Institute Meaning changes channel, the method that the most traditional frequency hopping communications uses.

The change residence time real-time by changing bit rate, so that energy changes, it is adaptable to data are divided The transmission of group.So-called variable Rate refers to change the radio frequency transmission bit speed of radio communication according to certain algorithm pseudorandom Rate, i.e. every aerial residence time of bit radiofrequency signal is no longer changeless, but pseudorandom in a variety of bit rates Be changed.

By changing modulation system, reduce the dependency between transmission signal waveform, increase Tracking Jam and target is believed Number identification difficulty.Change modulation system, change the transmission amplitude of signal, frequency and phase place the most in the physical sense.In fact Matter is to change the parameter of signal waveform, adds signal and is identified the difficulty of intercepting and capturing.

So increasing modulation system and the change of transmitted bit speed on traditional frequency-hopping communication method, utilize three-dimensional The hopping patterns that isomery saltus step parameter generates, its complexity and hopping patterns amount of space have significantly increase, and then add The difficulty that hopping patterns is decoded by sniff side, thus the method realizing secure communication.

Compared with prior art, the had the beneficial effect that present invention of the present invention changes while channel hopping and penetrates Frequently parameter bits speed and modulation system, forms the hopping patterns simultaneously changed with bit rate, channel frequency and modulation system, In time domain, change the signal characteristics such as the residence time of waveform, bit period and wave amplitude, add the uncertainty of signal, Reduce tracked probability；On frequency domain, change the frequency spectrum of modulated signal, enhance the irrelevant of signal frequency spectrum Property so that sniff person is difficult to trace analysis signal characteristic.

To sum up, the method applied in the present invention, have the advantage that (1) saltus step by channel frequency, can defend single The malicious interference of channel is attacked；(2) in channel frequency saltus step simultaneously, by introducing bit rate and the saltus step of modulation system, change Become residence time and the timing waveform form of signal, drastically increased the non-correlation between signal waveform, frequency spectrum, increased Follow the tracks of interference and the cost of invasion wireless network, can effectively defend man-in-the-middle attack；(3) lightweight, can run in a distributed manner On each node in wireless sense network.

Accompanying drawing explanation

Fig. 1 is the actual effect schematic diagram that the present invention is obtained by spectrum analyzer from frequency domain；

Fig. 2 is the actual effect schematic diagram that the present invention is obtained by oscillograph from time domain.

Detailed description of the invention

The present invention uses CC1101 or CC2500 radio frequency chip and ATmega128 microprocessor to constitute wireless sensor node Point, runs embedded type wireless sensing net TinyOS operating system, the interface of design isomery radio frequency parameter saltus step switching and assembly, leads to Cross the programmable register of radio frequency chip, control to arrange channel frequency, modulation system, bit rate, it is achieved receiving-transmitting sides isomery Radio frequency parameter switches.

CC1101 frequency range: CC1101 can be operated in 300-348MHz, 387-463MHz and 779-928MHz frequency range； Support more modulation pattern (OOK, ASK, GFSK, 2-FSK, 4-FSK and MSK), can arrange between 1.2kbps to 500kbps Bit rate.

CC2500 frequency range: 2400.0MHz～2483.5MHz working frequency range；Support more modulation pattern (OOK, GFSK, 2-FSK and MSK)), the bit rate between 1.2kbps to 500kbps can be set.

The channel frequency of radio frequency chip has CHANNR register configuration, and it is the depositor of eight, and it is mainly used in Select the communication channel under a certain fundamental frequency.Low two values determining CHANSPC_E of MDMCFG1 modulation /demodulation depositor, MDMCFG0 modulation /demodulation depositor (8) determines the value of CHANSPC_M.Then, the value of above-mentioned depositor can be by below equation Calculate:

$f_{base}=\frac{f_{XOSC}}{2^{16}}\×FREQ\[23:0\]---\left(1\right)$

${\mathrm{\Δf}}_{CHANNEL}=\frac{f_{XOSC}}{2^{16}}\×(256+CHANSPC\_M)\×2^{CHANSPC\_E}\×CHAN---\left(2\right)$

$f_{carrier}=\frac{f_{XOSC}}{2^{16}}\×(FREQ\[23:0\]+(256+CHANSPC\_M)\×2^{CHANSPC\_E-2}\×CHAN)---\left(3\right)$

Wherein, formula (1) is fundamental frequency computing formula, formula (2) position channel spacing Bandwidth Calculation Formula, and formula (3) is public Formula (1) and formula (2) sum, be expressed as channel carrier frequencies.

The modulation system of radio frequency chip is configured by MDMCFG2 depositor, when using 2-FSK/GFSK modulation, DEVIATN depositor defines the expected frequency deviation of input signal in RX pattern.Utilize in DEVIATN depositor Frequency departure is programmed by DEVIATION_M and DEVIATION_E value.This value is index/mantissa's form, and final deviation can Drawn by formula 4

$f_{DEV}=\frac{f_{XOSC}}{2^{17}}\×(8+DEVIATION\_M)\×2^{DEVIATION\_E}---\left(4\right)$

The bit rate of radio frequency chip is configured by MDMCFG3 and MDMCFG4 depositor, computational methods such as formula (5) institute Showing, wherein, R_M represents complete 8 the binary values of depositor MDMCFG3, R_E represent depositor MDMCFG4 low 4 binary Value, f_xoscRepresent the crystal oscillator frequency of processor.

${\mathrm{Bit}}_{base}=\frac{(256+R\_M)\×2^{R\_E}}{2^{28}}\×f_{XOSC}---\left(5\right)$

As a example by CC1101 radio frequency chip, selected frequency hopping channel f₁=315MHz, f₂=433MHz, f₃=915Mhz；Will f₁、f₂、f₃Substitute into formula 3 respectively, be calculated the value of the CHANSPC_E of low two of three groups of MDMCFG1 modulation /demodulation depositors, And the value of the CHANSPC_M of MDMCFG0 modulation /demodulation depositor (8).

In like manner select bit rate r₁=9.6kbps, r₂=19.2kbps, r₃=38.4kbps；And selected modulation system m₁=ASK, m₂=FSK, m₃=MSK；And correspondence calculates the value in MDMCFG2, MDMCFG3 and MDMCFG4 depositor.More than by Parameter, can form ternary parameter array G{f of corresponding register value₁,r₁,m₁；f₁,r₁,m₂；......；f₃,r₃,m₃It is total to C=C_F ×C_M×C_RThe ternary parameter array of=27 groups of various combinations.

After ternary parameter array G is carried out M sequence, obtain a pseudorandom three-dimensional hopping sequences G ' { f_i,r_j,m_k}。 Then by the pseudorandom three-dimensional hopping patterns download configuration of communication configuration and generation to receiving-transmitting sides, and initialize.Logical The time synchronization protocol TPSN crossed in wireless sense network carries out receiving-transmitting sides time synchronized.

One, under continuous data transmission mode, after synchronously completing, by hopping patterns sequence after M sequence first group three Tuple parameters is sent to saltus step changeover module module, calls saltus step changeover module module and carries out radio frequency parameter switching.Receiving-transmitting sides Trigger simultaneously and choose current tlv triple, according to parameter bits speed r in current tlv triple, transmission packet greatest length l_max, calculate current residence time t=l_max/ r, obtains next saltus step t+ switching time Δ t, arranges next saltus step fixed for switching time Time device (wherein Δ t is the switch protecting time), transmitting and receiving data.

When receiving-transmitting sides triggers next saltus step intervalometer switching time, go back to hopping patterns sequence G ' { f_i,r_j,m_k, choose Next organizes triplet parameters, is sent to saltus step changeover module module, calls saltus step changeover module and carries out radio frequency parameter switching, and presses Current radio frequency parameter recalculates and arranges next saltus step intervalometer switching time, transmitting and receiving data.

Two, under cycle data transfer pattern, after synchronously completing, call saltus step changeover module module and carry out radio frequency parameter and cut Change.Receiving-transmitting sides triggers according to sampling period T simultaneously and arranges next saltus step intervalometer switching time, and the timer interval time is T.

Sender checks currently transmitted queue: if queue is not for empty, then send packet.When saltus step timing switching time After device triggers, go back to hopping patterns sequence, choose next group triplet parameters, be sent to saltus step changeover module module, call jumping Become changeover module module and carry out radio frequency parameter switching, and restart next saltus step intervalometer switching time timing, send next Individual packet is until queue is empty；If transmit queue is empty, after waiting that saltus step intervalometer switching time triggers, go back to saltus step figure Case sequence, chooses next group triplet parameters, is sent to saltus step changeover module module, calls saltus step changeover module module and penetrate Frequently parameter switching, and restart next saltus step intervalometer switching time timing.

When next saltus step intervalometer switching time of recipient triggers, go back to hopping patterns sequence G ' { f_i,r_j,m_k, choose down One group of triplet parameters, is sent to saltus step changeover module module, calls saltus step changeover module and carries out radio frequency parameter switching, and again Start next saltus step intervalometer switching time timing, wait data to be received.

Fig. 1 is that the actual effect that the present invention is tested to by the maximum retained-mode of spectrum analyzer from frequency domain is illustrated Figure, audiofrequency spectrometer parameter: mid frequency is 2.403GHz, sweep wide 4.401MHz, sweep time 10ms.As can be seen from the figure have 8 The channel frequency of individual saltus step, uses the modulation system of ASK simultaneously at first frequency signal, and second frequency signal uses Be the modulation system of 2-FSK, be indicated above isomery radio frequency multiparameter saltus step medium frequency and modulation system there occurs change.

Fig. 2 is the actual effect schematic diagram that the present invention is tested to by oscillograph from time domain, oscillograph parameter: between transverse axis Every 100ms, longitudinal axis interval 10mV.By sending a fixed-length data bag, contrast time of giving out a contract for a project illustrates to give out a contract for a project bit speed The change of rate.As can be seen from the figure the time of giving out a contract for a project of its correspondence of packet of equal length is respectively 100ms and 140ms, by This shows that in isomery multiparameter saltus step, bit rate change causes signal residence time to change.

The present invention tests radio sensing network node radio-frequency communication module used and is respectively CC1101 and CC2500, MCU Use is all ATmega128 processor.

Claims (2)

1. the wireless sense network safety communicating method of a lightweight isomery radio frequency parameter saltus step, it is characterised in that include following Step:

1) the channel frequency set F={f that hopping sequences is corresponding is generated_i| i=1,2 ... X}, f_iFor i-th in channel frequency set Channel frequency；Generate the bit rate set R={r that hopping sequences is corresponding_j| j=1,2 ... Y}, r_jFor in bit rate set Jth bit rate；Generate the modulation system set M={M that hopping sequences is corresponding_k| k=1,2 ... Z}, m_kFor modulation system collection Kth modulation system in conjunction；

2) channel frequency, bit rate and modulation system are carried out random combine, the radio frequency parameter configuration that total C kind is different, Obtain isomery radio frequency ternary argument sequence set, be designated as G{f_i,r_j,m_k, the computing formula of C is: C=C_F×C_R×C_M, whereinThe possible quantity selected for channel frequency；The possibility selected for the bit rate that residence time length is relevant Quantity；The possible quantity selected for modulation system；In conjunction with pseudo-random sequence to obtained ternary argument sequence set G {f_i,r_j,m_kInner parameter point carries out selecting control, thus generates random isomery radio frequency parameter hopping patterns sequence, be abbreviated as G′{f_i,r_j,m_k}；

3) the isomery radio frequency parameter hopping patterns sequence G ' { f that will have generated_i,r_j,m_kIt is provided in receiving-transmitting sides, and by synchronizing Method, makes transmitting-receiving communication two ends saltus step initial time synchronize；

4) receiving-transmitting sides is according to isomery radio frequency parameter hopping patterns sequence G ' { f_i,r_j,m_kOrder carry out parameter switching, arrange Enumerator n initial value is 1, if sequence G ' { f_i,r_j,m_kInitial configuration radio frequency parameter is g₁, it is expressed as hopping patterns sequence G ' { f_i, r_j,m_kFirst example, g in }₂It is expressed as hopping patterns sequence G ' { f_i,r_j,m_kSecond example, g in }_nIt is expressed as saltus step figure Case sequence G ' { f_i,r_j,m_kN-th example in }, the rest may be inferred；Wherein 1≤n≤C；When receiving-transmitting sides arranges next saltus step switching Between intervalometer；

5) when saltus step intervalometer switching time triggers, enumerator n adds 1, configures radio frequency parameter g_nIf, n≤C, start down hop Become intervalometer switching time, go to step 5)；If n is ＞ C, the most whole hopping patterns all travels through complete, goes to step 4), receiving-transmitting sides Again from isomery radio frequency parameter g₁Start.

The wireless sense network safety communicating method of lightweight isomery radio frequency parameter saltus step the most according to claim 1, it is special Levying and be, receiving-transmitting sides arranges the process of next saltus step intervalometer switching time and is: if under continuous data transmission mode, often After carrying out primary parameter switching, according to parameter bits speed r in current ternary argument sequence set, transmission packet is maximum Length l_max, calculate current residence time t=l_max/ r, arranging next saltus step timer value switching time is t+ Δ t, and Δ t is for cutting Change guard time；If under cycle data transfer pattern, receiving-transmitting sides triggers according to sampling period T simultaneously and arranges next saltus step Switching time intervalometer, next saltus step timer interval switching time time is T；T ＞ ＞ l_max/r_min, r_minFor minimum bit speed Rate.