CN103532674B - The transmission coded method of a kind of file based on complex network - Google Patents

Abstract

The transmission coded method of a kind of file based on complex network, relates to the reliability transmission field of wireless network data.Process is: add up file size to be transmitted, is grouped file waiting for transmission；A selected degree distribution；Multiple packet by packet basis of original to be output generate new packet, i.e. coded identification, makes original transmit in a network with the form of coded identification sequence；The present invention establishes the mapping relations between the complex network structures that the short-and-medium ring structure of LT code is corresponding, detect according to complex network structures and evade the becate structure in LT code cataloged procedure to greatest extent, improve its successfully decoded probability, construct a kind of transmission encoding scheme of file efficiently and reliably based on complex network.Transmitting particularly with the data in the wireless channel with time-varying characteristics, this invention, so that receiving terminal receives less data just can be recovered by initial data, is effectively increased the bandwidth availability ratio of channel, reduction propagation delay time.

Description

The transmission coded method of a kind of file based on complex network

Technical field

The present invention relates to the reliability transmission field of wireless network data, based on complex network particularly to a kind of employing Becate detects and evades the method that the LT code scheme of algorithm is transmitted file.

Background technology

Luby Transform code (being called for short LT code) is to be had without code check characteristic in the class that 2002 propose by Luby Digital fountain code.Its coding and decoding performance directly depends on the degree distribution of its coded identification.Preferable orphan is distributed in theory can Enough LT code coding/decoding performances realizing optimum, the coding symbol number that i.e. recovering K incoming symbol needs is K.But, due to based on The LT code of preferable orphan's distribution does not ensures that the element number of pretreatment collection is always 1 during whole decoding, pretreatment Collect small fluctuation and cause whole decoding procedure failure.In order to solve the problems referred to above, Luby further provides based on sane lonely The LT code of son distribution, it makes during whole decoding, and in pretreatment, element number is stable is more than in the range of 1 at one. The performance of the LT code being distributed based on sane orphan is better than the performance of LT code based on preferable orphan's distribution, becomes the one of current LT code Individual standard method for designing.Existing LT code scheme is mostly changing of being made based on the LT code to be distributed based on sane orphan Enter, such as the LT code being distributed based on secondary goodness, multiple-objection optimization LT code, the LT code etc. of employing chaology design.2012, Zhao etc. Utilize the short average path length characteristic of scales-free network, it is proposed that a class has the LT code of uncalibrated visual servo characteristic so that LT code Coding and decoding efficiency and successfully decoded probability had bigger improvement.And based on this, associated ideal orphan's degree of being distributed in Advantage in terms of release probability a, it is proposed that class has the LT code of sane uncalibrated visual servo characteristic, further improves the compiling of LT code Code performance.

The research of recent years finds that volume (translating) code performance of LT code is had by the appearance of becate and has a certain impact.For compiling For code process, coded identification expectation obtains the information of more incoming symbol transmission, but, the existence of becate makes incoming symbol Information repeat to pass to coded identification, cause the waste of coded identification.Zhang etc. in 2008 at " Little Cycle Elimination of Fountain codes using Distilling Correlative Columns " literary composition proposes Using extraction related column method to evade the becate structure in LT code, Zhou etc. is at " A cycle elimination algorithm For construction of LT codes " literary composition PEG algorithm is used for LT code becate detection and evade in algorithm so that Data have obtained more preferable successfully decoded probability in ideal communication channel.

Above two method all proposes just for the tetracyclic structure occurred in Tanner figure, and consideration is not more than or equal to The impact on LT code of the becate structure of six rings.Further, since the coded identification of LT code is on-demand generation, when channel condition is poor Time, the stochastic generation of degree will inevitably produce Fourth Ring and six ring structures, and now, both schemes change original coding symbol Number degree distribution.The incoming symbol causing decoding equal number needs to transmit more coded identification, takies more channel strip Wide.Therefore, the maximization becate problem of LT code remains a problem demanding prompt solution.

Summary of the invention

The deficiency existed for prior art, it is an object of the invention to provide the transmission of a kind of file based on complex network and compiles Code method, evades Fourth Ring and six ring structures of LT code during detection, to overcome the problem maximizing becate of LT code.

The technical scheme is that and be achieved in that: the transmission coded method of a kind of file based on complex network, including Following steps:

Step 1: add up file size to be transmitted, is grouped file waiting for transmission；

Described grouping process is: by bit order, file to be transmitted is divided into k group, and wherein, k is positive integer, and k >10³If the data volume in last packet is less than average amount, then by the remaining bits position zero padding in this packet；

Step 2: select a degree distribution according to k value；

Step 3: generate new packet, i.e. coded identification in multiple packet by packet basis of original to be output, make original Transmit in a network with the form of coded identification sequence；

Step 3.1: generate first coded identification；

Step 3.1.1: degree distribution one value d of stochastic generation selected by step 2, randomly chooses d in former output file Individual different packet, wherein, d is natural number；

Step 3.1.2: this d different packet carries out XOR, forms a new packet, this packet is just for generating First coded identification；

Step 3.1.3: the coded identification generated with step 3.1.2, as start node, generates one by a node group The network structure become；

Step 3.1.4: this coded identification is put and transmits in the channel；

Step 3.2: generate next coded identification；

Step 3.2.1: be distributed according to the degree of step 2, this degree be distributed stochastic generation another positive integer d ', at random from former Selecting a packet in k packet of file, it is former that this be grouped into generation next coded identification selection first had selected The packet of file, is also first the optional packet generating next coded identification.Add a new node in the network architecture. If the packet of original selected be generate other certain or some there is a packet of coded identification, then, this Even limit, and limit is had between the node that individual new node is the most corresponding with above-mentioned certain or some already present coded identification Weights be select original a packet being grouped in all k originals in sequence number；If d '=1, then perform step 3.2.2；Otherwise perform step 3.2.3；

Step 3.2.2: all zero bit sequence isometric with it that be grouped of the original that step 3.2.1 selects carries out different Or, forming a new packet, this is grouped into the next coded identification of generation, this coded identification is put and passes in the channel Defeated, continue executing with to step 3.3；

Step 3.2.3: in all packets of original in addition to for generating the packet that next coded identification had been selected, surplus Under packet in select another packet of original, this be grouped into generate that another of next coded identification selected point Group；

Step 3.2.4: find out that all another packets by step 3.2.3 participate in generating exist coded identification and Its node corresponding in the network architecture, checks that the node that the new node in step 3.2.1 is the most corresponding with these exists even limit. If there is not even limit, showing that another packet selected does not results in the tetracyclic structure of LT code, then continuing to hold from step 3.2.5 OK；If there is even limit, then showing that this another packet will result in the tetracyclic structure of LT code, this another packet is not to generate next The optional packet of individual coded identification.Now, if yet suffering from dividing of the original into generating the next the most selected mistake of coded identification Group, then return to step 3.2.3 and continue executing with, otherwise arrive step 3.2.9 and continue executing with；

Step 3.2.5: find out that all another packets by step 3.2.3 participate in generating exist coded identification and Its node corresponding in the network architecture, checks whether the node that there is even limit in the network architecture with new node is grouped with another There is even limit in the coded identification node corresponding in the network architecture that exists participating in generating.If there is not even limit or existence even The weights on limit and limit are grouped in the sequence number in all packets of original equal to another, then show that another packet will not Cause six ring structures of LT code, this another be grouped into the optional packet generating next coded identification, continue to hold to step 3.2.6 OK；If there is even limit, and the weights connecting limit are not equal to another sequence number being grouped in the packet of original, then show to exist Six ring structures, i.e. this another packet will result in six ring structures of LT code, and this another packet is not to generate next coded identification Optional packet.Now, if yet suffering from the packet of the original of the most selected mistake, then return to step 3.2.3 and continue executing with；No Then, continue executing with from step 3.2.9；

Step 3.2.6；Find out that all another packets by step 3.2.3 participate in generating exist coded identification and Its node corresponding in the network architecture, adds the node of these correspondences and the company limit of new node, the power on limit in the network architecture Value is grouped in the sequence number in all packets of original for another；

Step 3.2.7: if optional grouping number continues executing with from step 3.2.8 equal to d ', if optional grouping number Individual less than d ', then continue executing with from step 3.2.9；

Step 3.2.8: the individual packet of this d ' carries out XOR and obtains a new packet, what this was new is grouped into next coding Symbol.This coded identification is put and is transmitted in the channel；Perform step 3.3；

Step 3.2.9: if yet suffering from the packet of the original of the most selected mistake, then repeat step 3.2.3；If the most not The packet of selected mistake, then arbitrarily select the packet of original beyond optional packet, until selected packet count is that d ' is Only.The individual packet of this d ' carries out XOR and generates a new packet, i.e. next coded identification, and this coded identification is placed on channel In be transmitted；

Step 3.3: the process of repeated execution of steps 3.2, generates remaining coded identification, until transmitting terminal receives reception Till the feedback information that the file that end returns to the most correctly recovers.

Beneficial effects of the present invention: the present invention establishes between the complex network structures that the short-and-medium ring structure of LT code is corresponding Mapping relations, detect according to complex network structures and evade the becate structure in LT code cataloged procedure to greatest extent, improve Its successfully decoded probability, constructs a kind of transmission encoding scheme of file efficiently and reliably based on complex network.Particularly with There is the data transmission in the wireless channel of time-varying characteristics, this invention so that receiving terminal to receive less data the most permissible Initial data is recovered, is effectively increased the bandwidth availability ratio of channel, reduce propagation delay time.

Accompanying drawing explanation

Fig. 1 is that the file that bit number is N=k L is divided equally into k packet schematic diagram by embodiment of the present invention；

Fig. 2 is that the file that bit number is N=k L-δ (δ < L) is divided into k packet schematic diagram by embodiment of the present invention；

Fig. 3 is the schematic diagram that embodiment of the present invention randomly generates angle value d；

Fig. 4 is that embodiment of the present invention selects d=3 different packet schematic diagram in original；

Fig. 5 is the network G schematic diagram of embodiment of the present invention only one of which node；

Fig. 6 is the schematic network structure after embodiment of the present invention generates the 2nd coded identification；

One of the 3rd coded identification of generation is selected to be grouped into S if Fig. 7 is embodiment of the present invention₂, cause tetracyclic structure Schematic network structure；

Fig. 8 is that embodiment of the present invention selects one of the 4th coded identification of generation to be grouped into S₄, cause six ring structures Schematic network structure；

Fig. 9 is the schematic network structure constituted after embodiment of the present invention generates the 5th coded identification；

Figure 10 is that embodiment of the present invention file based on complex network transmits coded method flow chart；

Figure 11 is that embodiment of the present invention first coding generates process flow diagram flow chart；

Figure 12 is LT code and the tradition LT code comparison curves in terms of successfully decoded probability of embodiment of the present invention composition, Wherein packet count is 10⁴。

Detailed description of the invention

Below in conjunction with the accompanying drawings embodiment of the present invention is described in further detail.

File based on the complex network transmission coded method used in present embodiment, as shown in Figure 10.Concrete steps As follows:

Step 1: add up file size to be transmitted, is grouped file waiting for transmission.

If data waiting for transmission are file, the most first want statistics file size, use C language in the present embodiment Fopen () function opens file, uses fseek () function by the position of needle locating to file, passes through to know with ftell () function The position of not last byte obtains the size of file.If data waiting for transmission are bit stream, the most directly treat transmitted bit and flow to Row is grouped.Described grouping process is: by bit order, file to be transmitted is divided into K group, and wherein, K is positive integer, And K > 10³.Assume that file to be transmitted can be converted into the bit stream of 2KB, can use said method that this bit stream is divided into K=2000 Group, the most each packet comprises L=8 bit.As it is shown in figure 1, wherein

First packet: total 8bits, content is 01011000；

Second packet: total 8bits, content is 10110011；

……

The K=2000 packet: total 8bits, content is 11100101.

In the present embodiment, the file of 2KB (16000bit) just can be divided into the packet of 2000 8bit.But For some file, it just can not be divided into multiple packet, i.e. the data volume of last packet after division is less than Packeting average data volume.At this time, it may be necessary in the end zero padding that last is grouped so that last is grouped the bit number comprised Average number of bits equal to each packet.Such as: assume the file of a 15994bit to be grouped, still by bit flow point Becoming 2000 groups, often group comprises L=8 Bit data, then last packet is by less than 8, it would be desirable to mend 0 behind.Such as figure Shown in 2, wherein

First packet: total 8bits, content is 01011000；

Second packet: total 8bits, content is 10110011；

……

The K=2000 packet: total 8bits, content is 11000000.Wherein last 6bit is filler.

Through said process, the file of one 2KB can be divided into 2000 groups by us.

Step 2: select a degree distribution according to the value of packet count K；

Described degree distribution can use sane orphan to be distributed, may be used without scale-free degree distribution and sane uncalibrated visual servo divides The degree distribution of the coded identification of the existing common LT code such as cloth, user can need to select voluntarily distribution function according to oneself. Dividing as a example by μ (d) cloth by sane orphan in present embodiment, the determination process of degree of explanation distribution is as follows:

μ (d) is defined as follows,

$\mathrm{\&mu;}\left(d\right)=\frac{\mathrm{\&rho;}\left(d\right)+\mathrm{\&tau;}\left(d\right)}{{\mathrm{\&Sigma;}}_{i=1}^K(\mathrm{\&rho;}\left(i\right)+\mathrm{\&tau;}\left(i\right))},\&ForAll;d=\mathrm{1,2}...,K-1,K.---\left(1\right)$

Wherein

And

$\mathrm{\&rho;}\left(d\right)=\left\{\begin{array}{cc}\frac{1}{K},& d=1\\ \frac{1}{d(d-1)},& d=\mathrm{2,3},...,K\end{array}\right.$

In formula, S be decoding process each step in desired remaining degree be the coding symbol number of 1:

$S=\mathrm{\&beta;}\sqrt{K}\ln K/\mathrm{\&delta;}>1---\left(2\right)$

In formula, β ∈ (0,1) is a free variable, and δ represents when receiving terminal receives K coded identification, tolerable decoding Error probability.

For all of K value, sane orphan is distributed needs to meet equation below:

${\mathrm{\&Sigma;}}_{d=1}^K\mathrm{\&mu;}\left(d\right)=1$

Research finds that during δ=1.0, the LT code being distributed based on sane orphan has when parameter beta=0.1 of sane orphan distribution Preferably performance.By β=0.1, δ=1.0, K=10000 substitutes into formula (2), can obtain S=92.10.And then when can obtain K=10000, compile The degree distribution of code sign.

In like manner, similar method can be used, try to achieve the parameter in scale-free degree distribution and sane scale-free degree distribution, determine It is distributed to the degree of the LT code of defining K value.

As a example by K=2000 the packet that the file of 2KB in present embodiment is divided into, by β=0.1, δ=1.0, K=2000 substitutes into It is 33.99 that formula (2) obtains the value of S.The value of S, δ substitute into formula (1) just can obtain packet number be 2000 based on steadily and surely The degree distribution of orphan's indexing.

Step 3: generate new packet in 2000 packet by packet basis of the original that size to be output is 2KB, i.e. encode Symbol, makes original transmit in a network with the form of coded identification sequence；2000 packets of original are referred to as input symbol Number.This implementation process is simple in order to describe, and introduces its part as a example by only have selected 5 incoming symbols in 2000 incoming symbols The generation process of coded identification.These 5 groups of incoming symbols are designated as S respectively₁,S₂,S₃,S₄,S₅, wherein S₁=01011000, S₂= 10110011, S₃=11100101, S₄=01011000, S₅=10110010。

Step 3.1: generate first coded identification, as shown in figure 11.

Step 3.1.1: in the present embodiment, degree distribution stochastic generation one the value d selected according to step 2₁, work done in the manner of a certain author is The degree of first coded identification.From S₁,S₂,S₃,S₄,S₅These 5 groups of incoming symbols select d₁Group is used for generating first coding Symbol.Value d₁Selection course as follows:

The degree distribution selected according to step 2, the variable d in formula (1) takes 1 respectively ..., it is 1 that K different value can be spent ..., K Probability shared by coded identification.Because the present embodiment carries out example with the cataloged procedure of 5 groups in 2000 groups, therefore, this Place is we assume that K=5, and limits d and take the integer between [1,5].First, 0-1.0 scope is divided into 5 according to this probability Section；Then a random number is produced with the rand () function in C language, it is judged that this random number is which of these 5 segmentations of 0-1.0 Individual segmentation, in which segmentation, then the angle value of first coded identification selected by step 3.1.1 is just for several.As it is shown on figure 3, Degree of hypothesis be the probability of 1 be 0.1, degree is the probability 0.4 of 2, degree be the probability of 3 be 0.3, degree be the probability of 4 be 0.15, degree is 5 Probability be 0.05.Application cumulative distribution, if the size of random number is between 0～0.1, then the angle value selected is 1；If it is random The size of number is between 2～0.5, then the angle value selected is 2；By that analogy.

Now, it is assumed that producing a value is the random number of 0.51, as shown in Figure 3, it is known that 0.51 is more than 0.5, less than 0.8, I.e. fall in the 3rd segmentation, therefore, plan the degree d of first coded identification₁It is entered as 2.

In 5 packets of original, randomly choose 3 different packets, select the probability phase of arbitrary packet of original With, in the present embodiment, this probability is 1/5.

Rand () function 2 randoms number of generation in employing C language in present embodiment, respectively 0.29,0.17.They Falling in the 2nd segmentation as shown in Figure 4 and the 1st segmentation, therefore, 2 selected by this step for generating first The packet of the original of coded identification is respectively the 1st packet and the 2nd packet.

Step 3.1.2: first packet in present embodiment is designated as C₁, C₁Select equal to step 3.1.1 2 of value The XOR of different original packets.That is, C₁=S₁⊕S₂=11101011；

Step 3.1.3: the coded identification generated with step 3.1.2, as start node, generates one by a node group Network structure G become, as shown in Figure 5.In the present embodiment, refer to coded identification C₁Corresponding node V₀Generation network is tied Structure G, this step is primarily to initialize G, and the content related to mainly includes using the malloc () function in C language Initialize node and the limit of G.

Step 3.1.4: coded identification C₁Put and transmit in the channel；

Step 3.2: in the present embodiment, generates the 2nd coded identification；

Step 3.2.1: be distributed according to the degree of step 2, this degree be distributed the degree d of random second coded identification₂=1, at random From S₁, S₂, S₃, S₄, S₅These 5 packets select 1 packet, it is assumed that this is selected is grouped into S₁.One is added in network structure G New node V₁, because S₁It is to generate C₁A packet, then, C₂And C₁Node V corresponding on G₁,V₀Between there is even limit, And the weight on limit is S₁, as shown in Figure 6.

Owing to the angle value of the 2nd coded identification is 1 and selected is uniquely grouped into S₁, therefore, step 3.2 generate Two coded identifications C₂=S₁=01011000.And by C₂Put and be transmitted in the channel.

Step 3.3: in the present embodiment, generates the 3rd coded identification；

Step 3.3.1: randomly choose the degree of the 3rd coded identification according to the degree distribution of step 2, it is assumed that its value is d₃=3, Now we need at S₁, S₂, S₃, S₄, S₅These 5 packets select to meet 3 packets of condition.Its process is as follows:

Random from S₁, S₂, S₃, S₄, S₅These 5 packets select to generate the 1st packet of the 3rd coded identification, it is assumed that should Selected it is grouped into S₁.A new node V is added in network structure G₂, due to S₁It is to generate C₁And C₂An original point Group, then increase by one in G and connect node V₂With node V₀Weights be S₁Company limit, and one connect node V₂With joint Point V₁Weights be S₁Company limit.

Random from S₂, S₃, S₄, S₅The packet of these 4 originals select a packet as generating the 3rd coded identification The 2nd select packet, it is assumed that it is S₂。S₂Participation generates coded identification C₁, new node V simultaneously₂With C₁Corresponding node V₀There are weights is S₁Company limit, as shown in Figure 7.Yin Yin, selects S herein₂Tetracyclic structure will be caused, it be not one optional Packet.

Random from remaining packet S₃, S₄, S₅These 3 packets select a packet S₃, Fourth Ring and six is not constituted due to it Ring structure, so S₃Can be as the optional packet generating the 3rd coded identification.Again from remaining packet S₄, S₅In random Select a packet, it is assumed that for S₄If find S simultaneously₄It is placed in complex network structures and does not the most constitute Fourth Ring or six ring structures, Therefore S₄Also can be as the optional packet generating the 3rd coded identification.

Therefore, the 3rd coded identification C₃Can there is S₁, S₃, S₄These three coded identification XOR and obtain, i.e. C₃=S₁⊕S₃⊕S₄= 01100101, by coded identification C₃Put and be transmitted in the channel.

Step 3.4: in the present embodiment, generates the 4th coded identification C₄；

Step 3.4.1: randomly choose the degree of the 4th coded identification according to the degree distribution of step 2, it is assumed that its value d₄=2, this Time we need at S₁, S₂, S₃, S₄, S₅These 5 packets select to meet 2 packets of condition.Process is as follows:

Random from S₁, S₂, S₃, S₄, S₅These 5 packets select to generate the 1st packet of the 4th coded identification, it is assumed that should Selected it is grouped into S₂.A new node V is added in network structure G₃, due to S₂It is to generate coded identification C₁An original text The packet of part, therefore, adds one in G and connects node V₃With node V₀Weights be S₂Company limit.

At random from remaining 4 packet S₁, S₃, S₄, S₅Middle selection one packet S₄As generating the of the 4th coded identification 2 have been selected packet.Due in network structure G, new node V₃The node V being connected₀, with packet S₄The existence participating in generating is compiled Code sign C₃Corresponding node V₂Between there is even limit, and the weights on even limit are S₁≠S₄, as shown in Figure 8.So, select S herein₄Meeting Cause six ring structures, i.e. S₄It not to generate C₄An optional packet.

At random from remaining 3 packet S₁, S₃, S₅Middle selection one packet, it is assumed that selected be grouped into S₅, i.e. S₅As life The next one becoming the 4th coded identification has selected packet.Due to S₅Tetracyclic structure and six ring structures, therefore, S will not be constituted₅It is to generate Coded identification C₄Another optional packet.

By step 3.4, generate the 4th coded identification C in the present embodiment₄=S₂⊕S₅=00000001.Coding symbol Number C₄Put into channel to be transmitted.

Step 3.5: in the present embodiment, generates the 5th coded identification C₅；

Degree distribution according to step 2 randomly chooses the degree of the 5th coded identification, it is assumed that its value d₅=2, now need at S₁, S₂, S₃, S₄, S₅These 5 packets select to meet 2 packets of condition.Process is as follows:

Random from S₁, S₂, S₃, S₄, S₅These 5 packets select a packet as one of the 5th coded identification of generation Optional packet, it is assumed that this is grouped into S₃.A new node V is added in G₄, due to S₃Participation generates coded identification C₃, because of This, add one in G and connect node V₂And V₄Weights be S₃Limit.

At random from remaining 4 packet S₁, S₂, S₄, S₅These 4 packets select 1 packet, it is assumed that for S₂.Due in G with New node V₄There is the node V on even limit₂With S₂Participate in coded identification C generated₁Node V corresponding in G₀There is even limit, and limit Weights be S₁≠S₂, therefore, if herein by S₂Will result in six ring structures as optional packet.

At random from remaining 3 packet S₁, S₄, S₅These 3 packets select 1 packet, it is assumed that for S₁, as selecting point Group.Due to S₁Participate in coded identification C generated₃Node V corresponding in G₂With new node V₄There are weights is S₃Company limit, because of This, S₁Tetracyclic structure is will result in as optional packet.

At random from remaining 2 packet S₄, S₅Middle selection 1 packet, as generating coded identification C₅The next one selected point Group, it is assumed that for S₄.Due to S₄Participate in coded identification C generated₃Node V corresponding in G₂With new node V₄There are weights is S₃ Company limit, therefore, if S₄Tetracyclic structure is will result in as optional packet.

At random from remaining 1 packet S₅Middle selection 1 packet, this is grouped into S₅If select S herein₅I.e. do not result in four Ring structure does not results in six ring structures yet, so, S₅It is to generate coded identification C₅An optional packet.Due to S₅Participate in generating Coded identification C₄, so, G adds one and connects node V₃And V₄Weights be S₅Company limit.As shown in Figure 9.

By step 3.5, generate the 5th coded identification C in the present embodiment₅=S₃⊕S₅=01010111, C₅It is placed on Channel transmits.

Step 3.6: in the present embodiment, generates the 6th coded identification C₆；

Degree distribution according to step 2 randomly chooses the degree of the 6th coded identification, it is assumed that its value d₆=3.Now need at S₁, S₂, S₃, S₄, S₅These 5 packets select to meet 3 packets of condition.Process is as follows:

Random from S₁, S₂, S₃, S₄, S₅In these 5 packets, selection one packet can as 1 that generates the 6th coded identification Choosing packet, it is assumed that this is grouped into S₂.A new node V is added in G₅, due to S₂Participation generates coded identification C₁And C₄, because of This, add in G and connect V₅, V₀Weights be S₂Company limit and connect V₅, V₃Weights be S₂Company limit.

Random from S₁, S₃, S₄, S₅These 4 packets select 1 packet as having generated the 2nd of the 6th coded identification Choosing packet, it is assumed that this is grouped into S₁.Due in network structure G, S₁Participate in coded identification C generated₁Node corresponding in G V₀With new node V₅There are weights is S₂Company limit, therefore, if select S herein₁Tetracyclic structure will be caused.

At random from remaining 3 packet S₃, S₄, S₅Middle selection 1 packet is as generating C₆The 3rd select packet, it is assumed that This is grouped into S₃.Due in G with new node V₅There is the node V on even limit₀With S₃Participate in coded identification C generated₃Correspondence in G Node V₂Between to there are the weights on even limit and even limit be S₁≠S₃, therefore, S herein₃It it not an optional packet.

At random from remaining 2 packet S₄, S₅Middle selection one packet is as generating C₆The 4th select packet, it is assumed that for S₄.Due in G with new node V₅There is the node V on even limit₀With S₄Participate in coded identification C generated₃Node V corresponding in G₂Between The weights on existence even limit and even limit are S₁≠S₄, therefore, if S herein₄Six ring structures will be constituted as optional packet.

Analyze last packet S₅, due to S₅Participate in coded identification C generated₄Node V corresponding in G₃With new joint Point V₅There are weights is S₂Company limit, therefore, S₅Tetracyclic structure is will result in as optional packet.

In summary, if generating the 6th first selected by coded identification to be grouped into S₂, then no matter select S₁, S₃, S₄ Or S₅Becate structure will be caused.Now, from except S₂Outer S₁, S₃, S₄, S₅These 4 packets randomly choose 2 packets, it is assumed that For S₁, S₄, as generating coded identification C₆Two other optional packet.

The 6th coded identification C is obtained by step 3.6₆=S₂⊕S₁⊕S₄=10110011, C6 is put and carries out in the channel Transmission.

Generating 6 coded identifications by said process, they are all to be generated by 5 packets in original.At this In embodiment, for comprising the original of 2000 packets, it would however also be possible to employ identical method, generate coded identification sequence. At receiving terminal according to the value of coded identification and coded identification and the relation of multiple packets of original, original is recovered Come.

Present invention can be directly applicable to the Volume data such as video, image transmitting in wireless channel, for It is easy to verify feasibility and the advantage of described method, the most only from the encoding scheme of successfully decoded probability angle with tradition LT code It is analyzed.

The present invention with 1000 groups of incoming symbol numbers for 10⁴, block length be 1 bit there is sane uncalibrated visual servo characteristic As a example by LT code and the LT code that is distributed based on sane orphan, effectiveness of the invention is verified, wherein participate in the LT code bag of contrast Include；

(1) RD-SF (cycle-6priority): parameter selects P₁=0.1, λ=1.9, reduce Fourth Ring and six ring structures as far as possible The LT code with sane uncalibrated visual servo characteristic；

(2) RD-SF (cycle-4priority): parameter selects P₁=0.1, λ=1.9, reduce Fourth Ring as far as possible, do not consider six The LT code with sane uncalibrated visual servo characteristic of ring；

(3) RD-SF (random): parameter selects P₁=0.1, λ=1.9, do not consider that the sane nothing that has of Fourth Ring and six rings is marked The LT code of degree characteristic；

(4) RSD (cycle-6priority): parameter selects c=0.1, δ=1, reduces Fourth Ring and the base of six ring structures as far as possible In the LT code that sane orphan is distributed；

(5) RSD (cycle-4priority): parameter selects c=0.1, δ=1, reduces Fourth Ring as far as possible, does not consider the base of six rings In the LT code that sane orphan is distributed；

(6) RSD (random): parameter selects c=0.1, δ=1, does not consider being distributed based on sane orphan of Fourth Ring and six rings LT code.

This invention does not change the degree distribution of coded identification, therefore, generates the average XOR number of times that coded identification needs It is more or less the same with original coding scheme, but owing to Fourth Ring and six ring probabilities of occurrence reduce, recovers what identical incoming symbol needed Coding symbol number will decrease so that the average XOR number of times of program decoding process reduces.It is different coding as shown in table 1 The relativity of redundancy factor in scheme, redundancy factor is the lowest, and the coding symbol number that showing to recover original input symbol needs is got over Few, required decoding delay is the lowest:

The LT code of table 1 the present embodiment structure and the Performance comparision of tradition LT code

Analytical table 1 understands, and applies the average redundancy factor of LT code of six ring priority algorithms less than application Fourth Ring priority algorithm The average redundancy factor of LT, they both less than do not carry out the average redundancy factor of the LT code of becate optimization, therefore use becate The LT code evading algorithm recovers the coding symbol number of equal number of incoming symbol needs less than the LT code not carrying out becate optimization.

Owing to the degree of each coded identification is independent generation, and there is the LT code of sane uncalibrated visual servo characteristic and based on reason As long as thinking that the LT code that orphan is distributed receives enough coded identifications and is to ensure that recipient can decode completely, with transmission number According to channel condition unrelated, therefore, the most only consider to apply becate based on Complex Networks Theory to evade the LT code of algorithm resonable Think the successfully decoded probability under channel condition.

Figure 12 be incoming symbol number be 10⁴, construct 1000 groups of above-mentioned six kinds of LT codes respectively, obtain the successfully decoded of them Relation between probability and redundancy factor.

Analysis Figure 12 understands, and on the premise of redundancy factor is identical, it is sane without mark that having of algorithm generation evaded by application becate The successfully decoded probability of the LT code of degree characteristic is higher than the LT code with sane uncalibrated visual servo characteristic and additionally not considering becate structure Three kinds of LT codes being distributed based on sane orphan.And apply becate to evade the LT code being distributed based on sane orphan that algorithm generates, connect Receiving end receive the successfully decoded probability of equal number of coded identification N=(1+ α) K higher than do not consider becate structure based on surely The LT code of strong orphan's distribution.

The studies above shows, the LT code of algorithm design evaded by application becate can be in the premise ensureing to compile (translating) code efficiency Under so that successfully decoded probability is greatly improved.

Although the foregoing describing the detailed description of the invention of the present invention, but the those skilled in the art in this area should managing Solving, these are merely illustrative of, and these embodiments can be made various changes or modifications, without departing from the principle of the present invention And essence.The scope of the present invention is only limited by the claims that follow.

Claims (1)

1. file based on a complex network transmission coded method, it is characterised in that: comprise the following steps:

Step 1: add up file size to be transmitted, is grouped file waiting for transmission；

Described grouping process is: by bit order, file to be transmitted is divided into k group, and wherein, k is positive integer, and k ＞ 10³If the data volume in last packet is less than average amount, then by the remaining bits position zero padding in this packet；

Step 2: select a degree distribution according to k value；

Step 3: generate new packet, i.e. coded identification in multiple packet by packet basis of original to be output, makes original to compile The form of code sign sequence is transmitted in a network；

Step 3.1: generate first coded identification；

Step 3.1.1: degree distribution one value d of stochastic generation selected by step 2, randomly chooses d not in former output file Same packet, wherein, d is natural number；

Step 3.1.2: this d different packet carries out XOR, forms one new packet, this packet is just for the of generation One coded identification；

Step 3.1.3: the coded identification that generated with step 3.1.2, as start node, generates one and is made up of a node Network structure；

Step 3.1.4: this coded identification is put and transmits in the channel；

Step 3.2: generate next coded identification；

Step 3.2.1: be distributed according to the degree of step 2, this degree be distributed stochastic generation another positive integer d ', at random from original K packet in select a packet, this is grouped into first original selected generating the selection of next coded identification Packet, be also first the optional packet generating next coded identification；Add a new node in the network architecture, if choosing One packet of the original selected be generate other certain or some there is a packet of coded identification, then, this is new Even limit, and the power on limit is had between the node that node is the most corresponding with above-mentioned certain or some already present coded identification Value is the sequence number in a packet being grouped in all k originals of the original selected；If d '=1, then perform step 3.2.2；Otherwise perform step 3.2.3；

Step 3.2.2: all zero bit sequence isometric with it that be grouped of the original that step 3.2.1 selects carries out XOR, Forming a new packet, this is grouped into the next coded identification of generation, this coded identification is put and transmits in the channel, arrives Step 3.3 continues executing with；

Step 3.2.3: in all packets of original in addition to for generating the packet that next coded identification had been selected, remaining Selecting another packet of original in packet, this is grouped into another packet selected generating next coded identification；

Step 3.2.4: find out that all another packets by step 3.2.3 participate in generating exist coded identification and Node corresponding in network structure, checks that the node that the new node in step 3.2.1 is the most corresponding with these exists even limit, if not There is even limit, show that another packet selected does not results in the tetracyclic structure of LT code, then continue executing with from step 3.2.5；If There is even limit, then show that this another packet will result in the tetracyclic structure of LT code, this another packet is not to generate the next one to compile The optional packet of code sign, now, if yet suffering from the packet of the original into generating the next the most selected mistake of coded identification, then Return to step 3.2.3 continue executing with, otherwise arrive step 3.2.9 and continue executing with；

Step 3.2.5: find out that all another packets by step 3.2.3 participate in generating exist coded identification and Node corresponding in network structure, checks whether the node that there is even limit in the network architecture with new node participates in another packet There is even limit in the node that there is coded identification correspondence in the network architecture of generation, if there is not even limit or existence to connect limit also And the weights on limit are grouped in the sequence number in all packets of original equal to another, then show that another packet does not results in Six ring structures of LT code, this another be grouped into the optional packet generating next coded identification, continue executing with to step 3.2.6； If there is even limit, and the weights connecting limit are not equal to another sequence number being grouped in the packet of original, then show to have six Ring structure, i.e. this another packet will result in six ring structures of LT code, and this another packet is not to generate next coded identification Optional packet, now, if yet suffering from the packet of the original of the most selected mistake, then returns to step 3.2.3 and continues executing with；Otherwise, Continue executing with from step 3.2.9；

Step 3.2.6: find out that all another packets by step 3.2.3 participate in generating exist coded identification and Node corresponding in network structure, adds the node of these correspondences and the company limit of new node in the network architecture, and the weights on limit are Another is grouped in the sequence number in all packets of original；

Step 3.2.7: if optional grouping number continues executing with from step 3.2.8, if optional grouping number is less than equal to d ' D ' is individual, then continue executing with from step 3.2.9；

Step 3.2.8: the individual packet of this d ' carries out XOR and obtains a new packet, what this was new is grouped into next coding symbol Number, this coded identification is put and is transmitted in the channel；Perform step 3.3；

Step 3.2.9: if yet suffering from the packet of the original of the most selected mistake, then repeat step 3.2.3；If it is the most selected The packet crossed, then arbitrarily select the packet of original beyond optional packet, until selected packet count is d '；This The individual packet of d ' carries out XOR and generates a new packet, i.e. next coded identification, and puts to enter in the channel by this coded identification Row transmission；

Step 3.3: the process of repeated execution of steps 3.2, generates remaining coded identification, until transmitting terminal receives receiving terminal and returns Back to the feedback information that the most correctly recovers of file till.