CN104022990A - Distributed beam forming carrier phase synchronization method based on sea wireless sensor network - Google Patents

Abstract

The invention relates to a distributed beam forming carrier phase synchronization method based on a sea wireless sensor network, and belongs to the technical field of wireless sensor networks and distributed beam forming. The distributed beam forming carrier phase synchronization method is provided to solve the problems that an existing time slot back-and-forth carrier synchronization method is poor in expansibility, phase synchronization between nodes is slow and a distributed beam can not reach a satellite in time due to small power of a single sensor, and is provided to suppress the Doppler effect appearing in the process of signal transmission between the nodes. The distributed beam forming carrier phase synchronization method includes the steps that the target node sends a single frequency beacon signal to the main node and the auxiliary node, and the main node after being processed through a phase discrimination circuit obtains a main node modulating signal; the auxiliary node sends the received single frequency beacon signal to the main node, and the single frequency beacon signal processed through the main node is sent to the auxiliary node again to form an auxiliary node modulating signal; the main node modulating signal and the auxiliary node modulating signal are superposed in an in-phase mode at the target node to obtain power gain. The distributed beam forming carrier phase synchronization method is further suitable for the wireless sensor networks.

Description

A kind of distributed wave beam based on sea wireless sense network forms carrier phase synchronization method

Technical field

The invention belongs to wireless sense network, distributed beam-forming technology field.

Background technology

Ocean is survive procreation and the important bases of social realization sustainable development of the mankind, exploitation ocean, Development of Marine economy are the only ways of whole human survival and social development, in view of the importance of ocean, the monitoring of oceanic resources and environment is just being become to a large focus of countries in the world research.Marine information adopts satellite to transmit as relaying conventionally, and flood and field difference, cannot set up large base station on sea and satellite communicates, and base station also cannot dispense at random on sea simultaneously.And sensor node is due to its low cost and small size, can dispense at random on sea, but the energy of single-sensor node is less, cannot directly communicate with satellite, realize sensor network and satellite direct communication so need utilize distributed (working in coordination with) wave beam of sea multisensor node to form long-distance transmissions technology, and carry out key problem that this distributed wave beam forms be carrier phase, time synchronously.

The existing carrier phase synchronization scheme that is applicable to distributed wave beam formation mainly contains two kinds: one of them is the Scalable Feedback Control for Distributed Beamforming in Sensor Networks (in sensor network, distributed wave beam forms extendible feedback) that the people such as R.Mudumbai propose.This method needs destination node to carry out several check and correction judgement to the phase information of source node, finally selects optimum a kind of result to carry out wave beam formation.Because this check and correction need to be carried out many times, namely destination node need to be communicated by letter frequently with source node, so be only applicable to the situation that the short distance wave beam using aircraft or terrestrial base station as relaying forms, be not suitable for the situation that sea transducer and satellite directly communicate.

Another kind is the Time-Slotted Round-Trip Carrier Synchronization (time slot comes and goes carrier synchronization) that the people such as D.Richard Brown propose.First this method sends to phase information institute's active node by destination node, thereby between source node, time-division slot carries out the phase-accumulated internodal Phase synchronization that obtains.Its advantage in not needing to carry out phase place check and correction with destination node frequently, is still linear structure due to what adopt between source node at source node, and its autgmentability is not strong.In the radio sensing network of sea, single-sensor power is less, the distributed wave beam of its output can not arrive satellite, and therefore for the rapidity that ensures satellite communication needs a large amount of sensor nodes, and this is just based on sea wireless sense network problem place anxious to be resolved.

Summary of the invention

The present invention comes and goes source node that carrier synchronization method occurs in the time being applied to sea transducer and satellite and directly communicating and adopts linear structure to cause Phase synchronization problem slowly by force and between node of the method autgmentability in order to solve existing time slot, also be the problem that can not arrive satellite in order to solve the less distributed light beam causing of single-sensor power, also be in order to suppress due to the sea Doppler effect that between the node that the sensor network nodes irregular movement that causes causes, signals transmission occurs that fluctuates, propose a kind of distributed wave beam based on sea wireless sense network and formed carrier phase synchronization method.

Distributed wave beam based on sea wireless sense network forms a carrier phase synchronization method, and this method is to carry out under the condition of not considering frequency and phase estimation error, and the method comprises the steps:

Step 1, source node Node _iobtain and store data copy signal m (t), source node Node _imiddle Node ₁for host node, Node _kfor from node, wherein, K is more than or equal to 2 positive integer; I is more than or equal to 1 positive integer; K ∈ i;

Step 2, destination node D are to source node Node _isend single-frequency beacon signal x ₀(t); Source node Node _ireceive described single-frequency beacon signal x ₀, and form source node and receive signal y (t) _0i(t);

Source node receives signal y _0i(t) y in ₀₁(t) represent that host node receives signal, y _0K(t) represent to receive signal from node;

Step 3, host node Node ₁host node is received to signal y ₀₁(t) carry out signal processing and obtain host node carrier signal x ₁₀(t), from node Node _kto receiving signal y from node _0K(t) carrying out signal processing obtains from node carrier signal x _k0(t);

Step 4, host node Node ₁described data copy signal m (t) are carried in to host node carrier signal x ₁₀(t) on, obtain host node modulation signal s ₁(t); From node Node _kdescribed data copy signal m (t) are carried in from node carrier signal x _k0(t) on, obtain from node modulation signal s _k(t);

Step 5, host node Node ₁by described host node modulation signal s ₁(t) be sent to destination node D; From node Node _kby described from node modulation signal s _k(t) be sent to destination node D;

Step 6, destination node D are by the host node modulation signal s receiving ₁(t) and from node modulation signal s _k(t) stack obtains destination node modulation signal S (t).

The present invention is also applicable to radio sensing network.

Beneficial effect of the present invention: the present invention adopts distributed wave beam to form environment, basic thought is the reciprocity property of utilizing on two-way approach, process the reversion of realizing route accumulation phase delay in the conjugation of node by signal, the phase delay producing on two-way approach is offseted, thereby it is synchronous to realize distributed wave beam carrier signal phase, and form wave beam at destination node place.In the present invention, source node adopts main-slave structure mode, phase information from node is concentrated by host node processing, feed back to afterwards from node, as the reference that transmits from node, on two-way reciprocal path, producing phase delay offsets reversion, realize the phase alignment of signal on carrier frequency point, each node is transmitted and reach Phase synchronization at target place, thereby and realized stack produce beam gain, strong and the distributed light beam of extensibility arrives satellite, this method has suppressed effectively due to the sea Doppler effect that between the node that the sensor network nodes irregular movement that causes causes, signals transmission occurs that fluctuates.

Brief description of the drawings

Fig. 1 is schematic diagram of the present invention;

Fig. 2 is method flow block diagram of the present invention;

Fig. 3 is phase identification of circuit figure;

Fig. 4 is the graph of a relation of power efficiency and phase error in embodiment nine;

Fig. 5 is that in embodiment nine, power efficiency is schemed over time;

Fig. 6 is that in embodiment nine, efficiency fiducial probability is schemed over time.

Embodiment

Embodiment one, seeing figures.1.and.2 illustrates present embodiment, a kind of distributed wave beam based on sea wireless sense network described in present embodiment forms carrier phase synchronization method, this method is to carry out under the condition of not considering frequency and phase estimation error, and the method comprises the steps:

Step 1, source node Node _iobtain and store data copy signal m (t), source node Node _imiddle Node ₁for host node, Node _kfor from node, wherein, K is more than or equal to 2 positive integer; I is more than or equal to 1 positive integer; K ∈ i;

Step 2, destination node D are to source node Node _isend single-frequency beacon signal x ₀(t); Source node Node _ireceive described single-frequency beacon signal x ₀, and form source node and receive signal y (t) _0i(t);

Source node receives signal y _0i(t) y in ₀₁(t) represent that host node receives signal, y _0K(t) represent to receive signal from node;

Step 3, host node Node ₁host node is received to signal y ₀₁(t) carry out signal processing and obtain host node carrier signal x ₁₀(t), from node Node _kto receiving signal y from node _0K(t) carrying out signal processing obtains from node carrier signal x _k0(t);

Step 4, host node Node ₁described data copy signal m (t) are carried in to host node carrier signal x ₁₀(t) on, obtain host node modulation signal s ₁(t); From node Node _kdescribed data copy signal m (t) are carried in from node carrier signal x _k0(t) on, obtain from node modulation signal s _k(t);

Step 5, host node Node ₁by described host node modulation signal s ₁(t) be sent to destination node D; From node Node _kby described from node modulation signal s _k(t) be sent to destination node D;

Step 6, destination node D are by the host node modulation signal s receiving ₁(t) and from node modulation signal s _k(t) stack obtains destination node modulation signal S (t).

In present embodiment, data message copy is that sensor network will be to the data of destination node/satellite transmission; Before wave beam forms and starts, in sensor network, each node obtains data storage by the data sharing mechanism between net.

The formation of wave beam mainly relies on two category nodes, destination node/satellite and source node, and source node is divided into host node and from node.

Process described in present embodiment is relatively static at hypothesis source node and destination node, ignores to carry out under the condition of impact of various disturbing factors.

In present embodiment, step 3 has realized carrier phase synchronization, and step 4, step 5 and step 6 have realized the stack of modulation signal, thereby has formed distributed wave beam, has solved the problem that the single-sensor power less distributed light beam causing can not satellite.Very fast from the forming process of node carrier signal and host node carrier signal in this method, realized source node and destination node Phase synchronization, and autgmentability is strong.

Embodiment two, present embodiment are that a kind of distributed wave beam based on sea wireless sense network described in embodiment one is formed to further illustrating of carrier phase synchronization method, in present embodiment, and the single-frequency beacon signal x described in step 2 ₀(t) expression formula is $x_0\left(t\right)=e^{j[w(t-t_0)+{\mathrm{\φ}}_0]};$

Wherein, t ₀represent initial time, φ ₀represent the initial phase of single-frequency single-frequency beacon signal at destination node D place, w is frequency, j ²=-1, t is the time;

Source node described in step 1 receives signal y _0i(t) expression formula is

$y_{0i}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0i})+{\mathrm{\φ}}_0]};$

Wherein, τ _0irepresent destination node D to source node Nodei (i=1,2 ..., K) the path delay of time;

In the time of i=1, host node receives signal and is

Work as i=2,3 ... when K, bring into after source node receives signal expression and be from node reception signal y _0K(t),

The expression formula that receives signal from node is

Embodiment three, illustrate present embodiment with reference to Fig. 3, present embodiment is that a kind of distributed wave beam based on sea wireless sense network described in embodiment one or two is formed to further illustrating of carrier phase synchronization method, in present embodiment, the Node of host node described in step 3 ₁host node is received to signal y ₀₁(t) carry out signal processing and obtain host node carrier signal x ₁₀(t), the process that obtains described host node carrier signal is realized by phase identification of circuit, and the process that obtains described host node carrier signal is:

Step 3 one, host node Node ₁in local oscillator produce local oscillated signal O ₁(t), its expression formula is wherein, φ ₁represent the initial phase of local signal;

Step 3 two, according to the local oscillated signal O in step 3 one ₁(t), host node Node ₁host node receive signal y ₀₁(t) can also be expressed as:

$y_{01}\left(t\right)=O_1\left(t\right)e^{j[w(-{\mathrm{\τ}}_{01})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]}=O_1\left(t\right)h\left(t\right)$

Wherein, that host node receives signal y ₀₁(t) with signal O ₁(t) phase difference, the conjugated signal of h (t) $h^{*}\left(t\right)=e^{j[w(-{\mathrm{\τ}}_{01})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]};$

Step 3 three, described local oscillated signal O ₁(t) with conjugated signal h ^*(t) multiply each other and obtain host node carrier signal x ₁₀(t), described host node carrier signal x ₁₀(t) expression formula is $x_{10}\left(t\right)=O_1\left(t\right)\·h^{*}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{01})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

Embodiment four, present embodiment are that a kind of distributed wave beam based on sea wireless sense network described in embodiment one or two is formed to further illustrating of carrier phase synchronization method, in present embodiment, described in step 3 from node Node _kto receiving signal y from node _0K(t) carrying out signal processing obtains from node carrier signal x _k0(t), described acquisition from the process of node carrier signal is:

Step 3 A, from node Node _kto the single-frequency beacon signal x receiving ₀(t) carry out obtaining the single-frequency beacon signal x after continuation after periodic extension _0K(t), $x_{0K}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K})+{\mathrm{\φ}}_0]};$

Single-frequency beacon signal x after described continuation _0K(t) by from node Node _kbe denoted as from node and receive signal y _0K(t), from node Node _kreceive signal y by described from node _0K(t) be forwarded to host node Node ₁;

Step 3 B, host node Node ₁after periodic extension, receive signal y by what receive from node _0K(t) be denoted as and receive signal y from node after continuation _k1(t); $y_{K1}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0]};$

Step 3 C, host node Node ₁to receiving signal y from node after described continuation _k1(t) carry out phase identification of circuit processing and obtain principal and subordinate's signal x _1K(t); $x_{1K}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{0K}+{\mathrm{\τ}}_{K1})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]};$

Step 3 D, host node Node ₁by described principal and subordinate's signal x _1K(t) be back to again from node Node _k, from node Node _kby described principal and subordinate's signal x _1K(t) be denoted as from main signal y _1K(t);

Step 3 E, from node Node _kby described from main signal y _1K(t) be converted into from node carrier signal x _k0(t), $x_{K0}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{0K})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

Embodiment five, present embodiment are that a kind of distributed wave beam based on sea wireless sense network described in embodiment four is formed to further illustrating of carrier phase synchronization method, in present embodiment, and the Node of host node described in step 3 C ₁to receiving signal y from node after described continuation _k1(t) carry out phase identification of circuit processing and obtain principal and subordinate's signal x _1K(t),, obtain principal and subordinate's signal x _1K(t) process is:

Step C1, host node Node ₁in local oscillator produce local oscillated signal O ₁(t), its expression formula is wherein, φ ₁represent the initial phase of local signal;

Step C2, according to the local oscillated signal O in step C1 ₁(t), host node Node ₁continuation after receive signal y from node _k1(t); $y_{K1}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0]};$ Can also be expressed as:

$y_{K1}\left(t\right)=O_1\left(t\right)e^{j[w(-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]}=O_1\left(t\right)h_0\left(t\right);$

Wherein, to receive signal y from node after continuation _k1(t) with local oscillated signal O ₁(t) phase difference, τ _k1represent from node Node _kto host node Node ₁path delay; h ₀(t) conjugated signal $h^{*}\left(t\right)=e^{-j[w(-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]};$

Step C3, described local oscillated signal O ₁(t) with conjugated signal h ₀ ^*(t) multiply each other and obtain principal and subordinate's signal x _1K(t), described principal and subordinate's signal x _1K(t) expression formula is $x_{1K}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{0K}+{\mathrm{\τ}}_{K1})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

Embodiment six, present embodiment are that a kind of distributed wave beam based on sea wireless sense network described in embodiment one is formed to further illustrating of carrier phase synchronization method, in present embodiment, and the modulation signal of host node described in step 4 s ₁(t) expression formula is:

$s_1\left(t\right)={m\left(t\right)\·x_{10}\left(t\right)=m\left(t\right)e}^{j[w(t-t_0+{\mathrm{\τ}}_{01})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]};$

Described from node modulation signal s _k(t) expression formula is:

$s_K\left(t\right)={m\left(t\right)\·x_{K0}\left(t\right)=m\left(t\right)e}^{j[w(t-t_0+{\mathrm{\τ}}_{0K})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

Embodiment seven, present embodiment are that a kind of distributed wave beam based on sea wireless sense network described in embodiment one is formed to further illustrating of carrier phase synchronization method, in present embodiment, the expression formula of the modulation signal of destination node described in step 6 S (t) is:

$S\left(t\right)=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{s}_i\left(t\right)=\mathrm{Nm}\left(t\right)e^{j[w(t-t_0)-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

Embodiment eight, present embodiment are that a kind of distributed wave beam based on sea wireless sense network described in embodiment two is formed to further illustrating of carrier phase synchronization method, in present embodiment,

Local oscillated signal O ₁(t) can also exist with the form of sinusoidal signal, be expressed as follows:

O ₁(t)＝cos[w(t-t ₀)+φ ₁]。

In present embodiment, host node Node ₁local oscillator produce local oscillated signal O ₁(t), signal indication is:

O ₁(t)＝cos[w(t-t ₀)+φ ₁] (4-1)

Node ₁the signal y receiving ₀₁(t) be expressed as follows:

y ₀₁(t)＝cos[w(t-t ₀-τ ₀₁)+φ ₀] (4-2)

Y ₀₁(t) can resolve into O ₁(t) in-phase component and the form of quadrature component, as follows:

y ₀₁(t)＝y _I(t)·cos[w(t-t ₀)+φ ₁]+y _Q(t)·sin[w(t-t ₀)+φ ₁] (4-3)

Wherein y _i(t), y _q(t) represent respectively the coefficient function of in-phase component and quadrature component, arrangement can obtain

$\left\{\begin{array}{c}{y}_I\left(t\right)=\cos [w(-{\mathrm{\τ}}_{01})+{\mathrm{\φ}}_1-{\mathrm{\φ}}_1]\\ y_Q\left(t\right)=-\sin [w(-{\mathrm{\τ}}_{01})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]\end{array}\right.---(4-4)$

Accordingly, have and comprehensively go out signal x ₁₀(t) can be expressed as

$\begin{array}{c}{x}_{01}\left(t\right)=y_I\left(t\right)\·\cos [w(t-t_0)+{\mathrm{\φ}}_1]-y_Q\left(t\right)\·\sin [w(t-t_0)+{\mathrm{\φ}}_1]\\ =y_I\left(t\right)\·\cos [w(t-t_0)+{\mathrm{\φ}}_1]+y_Q\left(t\right)\·\sin [w(t-t_0)+{\mathrm{\φ}}_1+\mathrm{\π}]\end{array}---(4-5).$

Embodiment nine, present embodiment are to carry out all destination nodes and source node distribute identical condition to the evaluated error of frequency, phase place under, and in present embodiment, phase estimation error is embodied in φ ₀upper, be expressed as wherein φ _{err, k}represent the error that signal produces in the time being received for the k time;

It is upper that estimated frequency error is embodied in w, is expressed as wherein w _{err, k}represent the error that signal produces in the time being received for the k time.

Under the condition of considering frequency and phase estimation error, reanalyse the process of embodiment one to seven, simplify process herein as follows:

Destination node D to source node Nodei (i=1,2 ..., N) send single-frequency single-frequency beacon signal for simply, without loss of generality, establish t herein ₀=0; Each source node receives signal, is expressed as

$y_{0i}\left(t\right)=e^{j[\hat{w}t-w{\mathrm{\τ}}_{0i}+\widehat{{\mathrm{\φ}}_0}]}$

Host node receives signal $y_{01}\left(t\right)=e^{j[\hat{w}t-w{\mathrm{\τ}}_{01}+\widehat{{\mathrm{\φ}}_0}]};$ Receive signal from node $y_{0K}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K})+{\mathrm{\φ}}_0]}.$

Host node is received signal y by host node ₀₁(t) process and obtain host node carrier signal x through phase identification of circuit ₁₀' (t), this host node carrier signal is sent to destination node D by host node.

To receive signal y from node from node _0K(t) be transmitted to host node, host node y _0K(t) be denoted as and receive signal y from node after continuation _k1' (t);

${y_{K1}}^{\′}\left(t\right)=e^{j\left[\hat{\hat{w}}t-\hat{w}{\mathrm{\τ}}_{K1}-w{\mathrm{\τ}}_{0K}+\hat{\widehat{{\mathrm{\φ}}_0}}\right]}$

After the described continuation of host node, receive signal y from node _k1' (t) comprehensively obtained signal principal and subordinate signal x after processing by phase identification of circuit _1K' (t),

${x_{1K}}^{\′}\left(t\right)=e^{j[(2w-\hat{\hat{w}})t+w{\mathrm{\τ}}_{0K}+\hat{w}{\mathrm{\τ}}_{K1}-\hat{\widehat{{\mathrm{\φ}}_0}}+2{\mathrm{\φ}}_1]}$

Host node is by principal and subordinate's signal x _1K' (t) feed back to from node, be from main signal y from node by this signal indication _1K' (t),

${y_{1K}}^{\′}\left(t\right)=e^{j[(2w-\widehat{\hat{\hat{w}}})t-2w{\mathrm{\τ}}_{K1}+\stackrel{\widehat{^}}{w}{\mathrm{\τ}}_{K1}+w{\mathrm{\τ}}_{0K}+\hat{w}{\mathrm{\τ}}_{K1}-\hat{\widehat{{\mathrm{\φ}}_0}}+2{\mathrm{\φ}}_1]}$

From node by described from main signal y _1K' (t) be converted into from node carrier signal x _k0' (t) and realize and the communicating by letter of destination node D.

Host node carrier signal and while arriving destination node D from node carrier signal, is expressed as:

$\begin{array}{c}{y}_{i0}\left(t\right)=e^{j[(2w-\widehat{\hat{\hat{w}}})t+(-w+\widehat{\hat{\hat{w}}}){\mathrm{\τ}}_{0i}-(2w-\hat{\hat{w}}-\hat{w}){\mathrm{\τ}}_{i1}-\hat{\hat{\widehat{{\mathrm{\φ}}_0}}}+2{\mathrm{\φ}}_1]}\\ =e^{j[\mathrm{wt}-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}{e}^{j[(w-\widehat{\hat{\hat{w}}})t+(w-2\hat{w}+\widehat{\hat{\hat{w}}}){\mathrm{\τ}}_{0i}-(2w-\hat{\hat{w}}-\hat{w}){\mathrm{\τ}}_{i1}+({\mathrm{\φ}}_0-\hat{\hat{\widehat{{\mathrm{\φ}}_0}}})]}\end{array}.$

Above result represents, under the condition existing in frequency, phase estimation error, carrier signal produces deviation in the phase place of destination node.Deviation phase is due to τ _i1be far smaller than τ _0iso the principal element in deviation phase is and process total time item therefore the signal indication that destination node D receives is as follows:

$Y\left(t\right)\≈e^{[\mathrm{wt}-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(e^{j[(w-\widehat{\hat{\hat{w}}})t+(w-2\hat{w}+\widehat{\hat{\hat{w}}}){\mathrm{\τ}}_{0i}+({\mathrm{\φ}}_0-\hat{\hat{\widehat{{\mathrm{\φ}}_0}}})]}\right)}_i$

Symbol () in Y (t) _irepresent for each source node Nodei (i=1,2 ..., N) different stochastic variables; In Y (t), using about equal sign, is to have omitted τ on the one hand _i1impact; On the other hand, for Node ₁, as broad as long treating, this allows completely in the time that nodes N is larger.

While considering the affecting of error, the form of the signal that destination node D receives, again write out as follows here:

$Y\left(t\right)\≈e^{[\mathrm{wt}-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(e^{j[(w-\widehat{\hat{\hat{w}}})t+(w-2\hat{w}+\widehat{\hat{\hat{w}}}){\mathrm{\τ}}_{0i}+({\mathrm{\φ}}_0-\hat{\hat{\widehat{{\mathrm{\φ}}_0}}})]}\right)}_i---(3-1)$

The power form P (t) of signal can be write as

$P\left(t\right)\≈{\left|\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(e^{j[(w-\widehat{\hat{\hat{w}}})t+(w-2\hat{w}+\widehat{\hat{\hat{w}}}){\mathrm{\τ}}_{0i}+({\mathrm{\φ}}_0-\hat{\hat{\widehat{{\mathrm{\φ}}_0}}})]}\right)}_i\right|}^2---(3-2)$

Formula (3-2) can further arrange and obtain:

$P\left(t\right)\≈{\left|\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(e^{j[(w_{\mathrm{err},1}+w_{\mathrm{err},2}+w_{\mathrm{eer},3})(t-{\mathrm{\τ}}_{0i})+({\mathrm{\φ}}_{\mathrm{err},1}+{\mathrm{\φ}}_{\mathrm{err},2}+{\mathrm{\φ}}_{\mathrm{err},3})]}\right)}_i\right|}^2---(3-3)$

Suppose frequency, the equal Normal Distribution of phase estimation error of signal, and the error that each estimation produces is separate, wherein formula (3-3) can be write as

$P\left(t\right)\≈{\left|\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(e^{j[w_{\mathrm{err}}t+{\mathrm{\φ}}_{\mathrm{err}}]}\right)}_i\right|}^2---(3-4)$

Wherein suppose t > > τ _0i, in formula (3-4), below respectively for w _err, φ _errimpact on received power is discussed.

(1) impact of phase error on power

The existence of phase error directly causes the decay of power, below draws the relation between system power decay and phase error size by emulation.The quantity N that supposes source node in simulation process is 100, and (actual power is expected and ideal power output N to obtain average system power efficiency by emulation ²ratio) variances sigma of η and phase error _φrelation, as shown in Figure 4.

(2) impact of frequency error on power

Different on the impact of system power efficiency from phase error, the phase accumulation that frequency error causes in time little by little decays performance.Below obtain under different frequency evaluated error condition by emulation equally, system power efficiency eta over time.Identical with (1), the quantity N of emulation hypothesis source node is 100.Simulation result as shown in Figure 5.

When frequency error one timing of signal, change in time, the probability that system power efficiency is not less than a certain thresholding reduces gradually, knows the power efficiency that cannot ensure certain lower limit probability.Below provide the variation relation that requires efficiency thresholding and time.In emulation, suppose that source node number N is 100, without loss of generality, frequency error is got σ _w=0.5Hz, result as shown in Figure 6.

Embodiment ten, present embodiment are embodiment, have illustrated that this method suppresses due to the fluctuate mode of the Doppler effect of signals transmission appearance between the node that the sensor network nodes irregular movement that causes causes of sea.

Node motion: astatic sea is moved sensor network nodes brokenly.On the one hand, internodal irregular relative motion makes in synchronization slot, has the impact of Doppler effect in signals transmission; On the other hand, wave beam forms in time slot, and the relative position relation of sensor network and destination node/satellite changes.For the node impact that present design is answered of moving is discussed, by the Kinematic Decomposition of nodes, the impact of each component motion on the stability of a system is discussed respectively.For simply and without loss of generality, be three components by the Kinematic Decomposition of network intermediate node: radially general character motion of sighting distance, the tangential general character motion of sighting distance, internetwork irregular movement, below will the impact of three components on systematic function be discussed respectively.

Be the impact of Doppler motion on master and slave node communication due to what discuss, so ignore the frequency, the phase estimation error that exist in signal receiving course, think that the phase place of signal, frequency are accurately estimated.Stress to discuss the impact of relative motion between node, without loss of generality, suppose host node Node ₁be actionless, move brokenly with respect to host node from node.With from node Node ₂for example, the inhibition scheme operation principle of Doppler effect impact from node and host node Phase synchronization process is described.

If from node Node ₂host node Node relatively ₁the speed of relative motion is v.Host node Node ₁local oscillator produce signal O ₁(t);

Destination node/satellite D broadcast single-frequency beacon signal x ₀(t).Node ₂receiving single-frequency beacon signal is

$y_{02}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{02})+{\mathrm{\φ}}_0]}---(5-1)$

From node Node ₂with host node Node ₁between do not have under the condition of relative motion, i.e. v=0; Wave beam forms in time slot TSN, Node ₂x transmits ₂₀(t), be expressed as

$x_{20}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{02})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}---(5-2)$

At Node ₂with Node ₁while there is relative motion, i.e. v ≠ 0.Node ₂by signal y ₀₂(t) be transmitted to Node ₁in process, be subject to the impact of Doppler effect, produce frequency deviation.Be designated as x' ₂₁(t), be expressed as

$x_{21}^{\′}\left(t\right)=e^{j[w\frac{c}{c-v}t-w(t_0+{\mathrm{\τ}}_{02})+{\mathrm{\φ}}_0]}---(5-3)$

X' ₂₁(t) through Node ₂with Node ₁between τ in the path delay of time ₂₁after, arrive node Node ₁, signal is received as

$y_{21}^{\′}\left(t\right)=e^{j[w\frac{c}{c-v}t-w\frac{c}{c-v}{\mathrm{\τ}}_{21}-w(t_0+{\mathrm{\τ}}_{02})+{\mathrm{\φ}}_0]}---(5-4)$

Node ₁by signal y' ₂₁(t) after processing, phase identification of circuit obtains signal x' ₁₂(t), be expressed as

$x_{12}^{\′}\left(t\right)=e^{j[(2w-w\frac{c}{c-v})t+w\frac{c}{c-v}{\mathrm{\τ}}_{21}+w({\mathrm{\τ}}_{02}-t_0)-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}---(5-5)$

Host node Node ₁by signal x' ₁₂(t) feed back to from node Node ₂, through Node ₁with Node ₂between τ in the path delay of time ₁₂=τ ₂₁shi Yanhou, x' ₁₂(t) arrive node Node ₂, be received as y' ₁₂(t), be expressed as

$y_{12}^{\′}\left(t\right)=e^{j[(2w-w\frac{c}{c-v})\frac{c+v}{c}t-(2w-w\frac{c}{c-v}){\mathrm{\τ}}_{21}+w\frac{c}{c-v}{\mathrm{\τ}}_{21}+w({\mathrm{\τ}}_{02}-t_0)-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}$

After arrangement, obtain

$y_{12}^{\′}\left(t\right)=e^{j[\frac{c^2-\mathrm{cv}+2v^2}{c^2-\mathrm{cv}}\mathrm{wt}+(2w\frac{c}{c-v}-2w){\mathrm{\τ}}_{21}+w({\mathrm{\τ}}_{02}-t_0)-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}---(5-6).$

Node ₂by signal y' ₁₂(t) be designated as x' as carrier signal ₂₀(t), rewriting is as follows

$x_{20}^{\′}\left(t\right)=e^{j[\frac{c^2-\mathrm{cv}+2v^2}{c^2-\mathrm{cv}}\mathrm{wt}+(2w\frac{c}{c-v}-2w){\mathrm{\τ}}_{21}+w({\mathrm{\τ}}_{02}-t_0)-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}---(5-7)$

With formula (5-2) contrast, result is as follows

$x_{20}^{\′}\left(t\right)=x_{20}\left(t\right)e^{\frac{2v^2}{c^2-\mathrm{cv}}\mathrm{wt}+\frac{2v}{c-v}w{\mathrm{\τ}}_{21}}---(5-8)$

Can be found out signal x' by formula (5-8) ₂₀and x (t) ₂₀(t) only differ from a factor analyze knownly, this factor characterizes, and frequency departure and phase deviation that between node, relative motion produces, be respectively because node speed of related movement v is very little compared with electromagnetic wave propagation speed c; On the other hand, node Node ₂and Node ₁between the propagation delay time τ of Path generation ₁₂very little, so this is because the deviation that Doppler effect produces can be ignored substantially, very little on the impact of systematic function.

Claims (8)

1. the distributed wave beam based on sea wireless sense network forms a carrier phase synchronization method, it is characterized in that, the method comprises the steps:

Step 1, source node Node _iobtain and store data copy signal m (t), source node Node _imiddle Node ₁for host node, Node _kfor from node, wherein, K is more than or equal to 2 positive integer; I is more than or equal to 1 positive integer; K ∈ i;

Step 2, destination node D are to source node Node _isend single-frequency beacon signal x ₀(t); Source node Node _ireceive described single-frequency beacon signal x ₀, and form source node and receive signal y (t) _0i(t);

Source node receives signal y _0i(t) y in ₀₁(t) represent that host node receives signal, y _0K(t) represent to receive signal from node;

Step 3, host node Node ₁host node is received to signal y ₀₁(t) carry out signal processing and obtain host node carrier signal x ₁₀(t), from node Node _kto receiving signal y from node _0K(t) carrying out signal processing obtains from node carrier signal x _k0(t);

Step 4, host node Node ₁described data copy signal m (t) are carried in to host node carrier signal x ₁₀(t) on, obtain host node modulation signal s ₁(t); From node Node _kdescribed data copy signal m (t) are carried in from node carrier signal x _k0(t) on, obtain from node modulation signal s _k(t);

Step 5, host node Node ₁by described host node modulation signal s ₁(t) be sent to destination node D; From node Node _kby described from node modulation signal s _k(t) be sent to destination node D;

Step 6, destination node D are by the host node modulation signal s receiving ₁(t) and from node modulation signal s _k(t) stack obtains destination node modulation signal S (t).

2. a kind of distributed wave beam based on sea wireless sense network according to claim 1 forms carrier phase synchronization method, it is characterized in that the single-frequency beacon signal x described in step 2 ₀(t) expression formula is

Wherein, t ₀represent initial time, φ ₀represent the initial phase of single-frequency reference signal at destination node D place, w is frequency, j ²=-1, t is the time;

Source node described in step 1 receives signal y _0i(t) expression formula is

$y_{0i}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\ι}}_{0i})+{\mathrm{\φ}}_0]};$

Wherein, τ _0irepresent destination node D to source node Nodei (i=1,2 ..., K) the path delay of time;

In the time of i=1, host node receives signal and is

Work as i=2,3 ... when K, bring into after source node receives signal expression and be from node reception signal y _0K(t),

The expression formula that receives signal from node is

3. a kind of distributed wave beam based on sea wireless sense network according to claim 1 and 2 forms carrier phase synchronization method, it is characterized in that the Node of host node described in step 3 ₁host node is received to signal y ₀₁(t) carry out signal processing and obtain host node carrier signal x ₁₀(t), the process that obtains described host node carrier signal is realized by phase identification of circuit, and the process that obtains described host node carrier signal is:

Step 3 one, host node Node ₁in local oscillator produce local oscillated signal O ₁(t), its expression formula is

wherein, φ ₁represent the initial phase of local signal;

Step 3 two, according to the local oscillated signal O in step 3 one ₁(t), host node Node ₁host node receive signal y ₀₁(t) can also be expressed as:

$y_{01}\left(t\right)=O_1\left(t\right)e^{j[w(-{\mathrm{\τ}}_{01})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]}=O_1\left(t\right)h\left(t\right)$

Wherein, that host node receives signal y ₀₁(t) with signal O ₁(t) phase difference, the conjugated signal of h (t) $h^{*}\left(t\right)=e^{j[w(-{\mathrm{\τ}}_{01})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]};$

Step 3 three, described local oscillated signal O ₁(t) with conjugated signal h ^*(t) multiply each other and obtain host node carrier signal x ₁₀(t), described host node carrier signal x ₁₀(t) expression formula is $x_{10}\left(t\right)=O_1\left(t\right)\·h^{*}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{01})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

4. a kind of distributed wave beam based on sea wireless sense network according to claim 1 and 2 forms carrier phase synchronization method, it is characterized in that, described in step 3 from node Node _kto receiving signal y from node _0K(t) carrying out signal processing obtains from node carrier signal x _k0(t), described acquisition from the process of node carrier signal is:

Step 3 A, from node Node _kto the single-frequency beacon signal x receiving ₀(t) carry out obtaining the single-frequency beacon signal x after continuation after periodic extension _0K(t), $x_{0K}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K})+{\mathrm{\φ}}_0]};$

Single-frequency beacon signal x after described continuation _0K(t) by from node Node _kbe denoted as from node and receive signal y _0K(t), from node Node _kreceive signal y by described from node _0K(t) be forwarded to host node Node ₁;

Step 3 B, host node Node ₁after periodic extension, receive signal y by what receive from node _0K(t) be denoted as and receive signal y from node after continuation _k1(t); $y_{K1}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0]};$

Step 3 C, host node Node ₁to receiving signal y from node after described continuation _k1(t) carry out phase identification of circuit processing and obtain principal and subordinate's signal x _1K(t); $x_{1K}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{0K}+{\mathrm{\τ}}_{K1})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]};$

Step 3 D, host node Node ₁by described principal and subordinate's signal x _1K(t) be back to again from node Node _k, from node Node _kby described principal and subordinate's signal x _1K(t) be denoted as from main signal y _1K(t);

Step 3 E, from node Node _kby described from main signal y _1K(t) be converted into from node carrier signal x _k0(t), $x_{K0}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{0K})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

5. a kind of distributed wave beam based on sea wireless sense network according to claim 4 forms carrier phase synchronization method, it is characterized in that the Node of host node described in step 3 C ₁to receiving signal y from node after described continuation _k1(t) carry out phase identification of circuit processing and obtain principal and subordinate's signal x _1K(t),, obtain principal and subordinate's signal x _1K(t) process is:

Step C1, host node Node ₁in local oscillator produce local oscillated signal O ₁(t), its expression formula is wherein, φ ₁represent the initial phase of local signal;

Step C2, according to the local oscillated signal O in step C1 ₁(t), host node Node ₁continuation after receive signal y from node _k1(t); $y_{K1}\left(t\right)=e^{j[w(t-t_0-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0]};$ Can also be expressed as:

$y_{K1}\left(t\right)=O_1\left(t\right)e^{j[w(-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]}=O_1\left(t\right)h_0\left(t\right);$

Wherein, to receive signal y from node after continuation _k1(t) with local oscillated signal O ₁(t) phase difference, τ _k1represent from node Node _kto host node Node ₁path delay; h ₀(t) conjugated signal $h^{*}\left(t\right)=e^{-j[w(-{\mathrm{\τ}}_{0K}-{\mathrm{\τ}}_{K1})+{\mathrm{\φ}}_0-{\mathrm{\φ}}_1]};$

Step C3, described local oscillated signal O ₁(t) with conjugated signal h ₀ ^*(t) multiply each other and obtain principal and subordinate's signal x _1K(t), described principal and subordinate's signal x _1K(t) expression formula is $x_{1K}\left(t\right)=e^{j[w(t-t_0+{\mathrm{\τ}}_{0K}+{\mathrm{\τ}}_{K1})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

6. a kind of distributed wave beam based on sea wireless sense network according to claim 1 forms carrier phase synchronization method, it is characterized in that the modulation signal of host node described in step 4 s ₁(t) expression formula is:

$s_1\left(t\right)={m\left(t\right)\·x_{10}\left(t\right)=m\left(t\right)e}^{j[w(t-t_0+{\mathrm{\τ}}_{01})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]};$

Described from node modulation signal s _k(t) expression formula is:

$s_K\left(t\right)={m\left(t\right)\·x_{K0}\left(t\right)=m\left(t\right)e}^{j[w(t-t_0+{\mathrm{\τ}}_{0K})-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

7. a kind of distributed wave beam based on sea wireless sense network according to claim 1 forms carrier phase synchronization method, it is characterized in that, the expression formula of the modulation signal of destination node described in step 6 S (t) is:

$S\left(t\right)=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{s}_i\left(t\right)=\mathrm{Nm}\left(t\right)e^{j[w(t-t_0)-{\mathrm{\φ}}_0+2{\mathrm{\φ}}_1]}.$

8. a kind of distributed wave beam based on sea wireless sense network according to claim 2 forms carrier phase synchronization method, it is characterized in that local oscillated signal O ₁(t) can also exist with the form of sinusoidal signal, be expressed as follows:

O ₁(t)＝cos[w(t-t ₀)+φ ₁]。