CN101714907B - Passive optical network communication method, passive optical network communication system, optical network unit and optical line terminal - Google Patents

Abstract

The invention discloses a passive optical network (PON) communication method, which comprises the following steps: utilizing wavelength division multiplexing technology to generate a plurality of optical carrier groups of which the wavelengths are different from each other, wherein each optical carrier group comprises a plurality of optical carriers of which the wavelengths are the same; adopting optical code division multiple access (OCDMA) technology to perform code division on the carriers of each wavelength; changing user signals into a signal sequence with spread-spectrum characteristic through chaotic spread-spectrum processing; distinguishing different users according to an address code of an OCDMA system on each carrier; and recovering an original signal through related decoding and matching operations at a receiving end. The invention also discloses a PON system, an optical line terminal (OLT) and an optical network unit (ONU). By adopting the PON communication method, the PON communication system, the OLT and the ONU of the invention, the OCDMA is performed on the basis of wavelength division multiplexing, and the address code of the OCDMA system is generated by adopting chaotic spread spectrum technology so that user capacity in the PON system is expanded.

Description

EPON communication means and system, optical network unit and optical line terminal

Technical field

The present invention relates to Technology of Light Access Network, particularly relate to a kind of EPON (PON) communication means and system, a kind of optical network unit (ONU) and a kind of optical line terminal (OLT).

Background technology

The PON technology is the optimal solution that solves at present the Access Network bandwidth bottleneck, realizes fiber entering household (FTTH).Present PON mainly comprises two classes, that is: the PON of the PON of wavelength division multiplexing (WDM) and time division multiplexing (TDM).Wherein, adopt the PON of wavelength division multiplexing can avoid the technological difficulties such as ONU range finding among the time-multiplexed PON and fast bit be synchronous, and have high bandwidth, protocol transparent, line speed independence, virtual point-to-point connection, high security and easy advantages such as upgradability, therefore, the PON of wavelength division multiplexing becomes increasingly conspicuous in the PON technology.

But, because there is non-linear phenomena in optical fiber, therefore after the number of wavelengths of the PON of wavelength division multiplexing system reaches certain threshold value, it is particularly outstanding that the bottleneck that interchannel is crosstalked becomes, the linearity increase of wavelength number can cause the exponential growth of cost, therefore, the quantity of the wavelength available of the PON system of present wavelength division multiplexing is restricted, because in the PON of wavelength division multiplexing system, the light signal of a wavelength is used to a user to carry out transfer of data, namely distinguish different users with different wavelength, so the number of wavelengths quantitative limitation causes present PON system can't realize jumbo user's access.

Summary of the invention

The invention provides a kind of PON communication means, be intended to enlarge the user capacity of PON system.

The present invention also provides a kind of PON system, is intended to the capacity of extending one's service.

The present invention also provides a kind of ONU, is intended to enlarge the user capacity of PON system.

The present invention also provides a kind of OLT, is intended to enlarge the user capacity of PON system.

For achieving the above object, technical scheme of the present invention is achieved in that

The invention discloses a kind of passive optical network PON communication means, the method comprises:

Transmitting terminal generates more than one light carrier group, and each light carrier group comprises the more than one light carrier that wavelength is identical, and wherein, the wavelength of the light carrier that different light carrier groups comprise is different;

Transmitting terminal adopts Chaotic Spreading Spectrum Technology to generate the address code of optical code division multiple access OCDMA system, the address code that the data that sends to a user is corresponding carries out being loaded on the light carrier after the spread processing, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission;

Transmitting terminal is coupled into one road coupled signal with all light carriers in the same light carrier group, and the coupled signal of all light carrier groups is multiplexed into transmitted signal sends to receiving terminal;

Receiving terminal receives transmitted signal, and transmitted signal is carried out wavelength (de) multiplexing, obtains single wavelength signals of an above different wave length;

Receiving terminal is shunted to light receiving signal identical more than with single wavelength signals of each wavelength, and each light receiving signal and the spectrum-spreading address code that presets are carried out computing, and operation result is carried out threshold judgement, obtains user data.

The address code that described employing Chaotic Spreading Spectrum Technology generates the OCDMA system comprises:

Utilize chaotic maps to produce a chaos sequence; The chaos sequence that produces is quantized; With the address code of the chaos sequence after quantizing as the OCDMA system;

Wherein,

The described chaos sequence of chaotic maps generation that utilizes is: adopt one-level logic Logistic mapping to produce chaos sequence; Described one-level logical mappings is:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described chaos sequence to generation is quantified as:

$a_n=\mathrm{sgn}\left(x_n\right)=\left\{\begin{array}{c}1,x_n\&GreaterEqual;0\\ -1,x_n<0\end{array}\right.,$ Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing;

Or,

The described chaos sequence of chaotic maps generation that utilizes is: adopt the two-level logic mapping to produce chaos sequence; Described two-level logic is mapped as:

According to x _N+1=f (x _n)=γ x _n(1-x _n), with initial value x ₀The beginning iteration obtains real-valued chaos sequence { x _k, k=0,1,2 ..., select { x _k, k=0,1,2 ... the middle part score value as initial condition, according to $y_{n+1}=f\left(y_n\right)=\frac{a}{2}(\frac{{\mathrm{\&gamma;}}_2}{2}-1)-\frac{{\mathrm{\&gamma;}}_2}{a}{y^2}_n$ Generate chaos sequence, wherein, k is a sequence number, x _kBe the k item in the chaos sequence, n is a sequence number, y _nBe the n item in the chaos sequence, a is real number, γ ₂Be fractal parameter, 3.57＜γ ₂≤ 4;

Described chaos sequence to generation is quantified as:

$y_n=\underset{i=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{a}_i{2}^{-(i+1)}\&ap;2^{-L}\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=2^{-L}{Y}_n,$

Wherein, $Y_n=\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=(a_0{a}_1{a}_2\&CenterDot;\&CenterDot;\&CenterDot;a_i\&CenterDot;\&CenterDot;\&CenterDot;a_{L-1}),$ Wherein, by y _nThe sequence that forms is the chaos sequence after quantizing, a _i=0,1, L is real number.

The invention also discloses a kind of passive optical network PON system, comprising: transmitting terminal and receiving terminal;

Described transmitting terminal generates more than one light carrier group, each light carrier group comprises the more than one light carrier that wavelength is identical, wherein, the wavelength of the light carrier that different light carrier groups comprise is different, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that the data that sends to a user is corresponding carries out being loaded on the light carrier after the spread processing, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission, all light carriers in the same light carrier group are coupled into one road coupled signal, and the coupled signal of all light carrier groups is multiplexed into transmitted signal sends to receiving terminal;

Described receiving terminal receives transmitted signal, transmitted signal is carried out wavelength (de) multiplexing, obtain single wavelength signals of an above different wave length, single wavelength signals of each wavelength is shunted to light receiving signal identical more than, each light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is carried out threshold judgement, obtain user data.

Described transmitting terminal comprises: optical line terminal OLT;

Described receiving terminal comprises: lambda router, more than one coupler and an above optical network unit ONU;

Described lambda router receives the descending transmitted signal from OLT, descending transmitted signal is carried out wavelength (de) multiplexing, obtain descending single wavelength signals of an above different wave length, descending single wavelength signals of a wavelength is sent to a coupler, and descending single wavelength signals of different wave length sends to respectively different couplers;

Each coupler receives the descending single wavelength signals from a wavelength of lambda router, and this descending single wavelength signals is shunted to descending light receiving signal identical more than, and a descending light receiving signal is sent to an ONU;

Each ONU receives a descending light receiving signal, and descending light receiving signal and the spectrum-spreading address code that presets are carried out computing, and operation result is carried out threshold judgement, obtains sending to self user's data.

Described transmitting terminal comprises: lambda router, more than one coupler and more than one optical network unit ONU; Described lambda router links to each other respectively with more than one coupler; Each coupler links to each other with part ONU among all ONU, and each ONU only connects a coupler;

Described receiving terminal comprises: optical line terminal OLT;

Described each ONU generates the up light carrier of a single wavelength, the more than one up light carrier group of the common generation of all ONU, wherein, the up optical carrier wavelength that the different ONU that links to each other from same coupler generates is identical, consist of a up light carrier group, the wavelength of the up light carrier that different up light carrier groups comprises is different; Each ONU adopts Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that a user's the data is corresponding is carried out being loaded on the up light carrier after the spread processing and is sent coupler to, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission;

Each coupler is coupled into all the up light carriers in the up light carrier group on the way, and capable coupled signal sends to lambda router;

Described lambda router receives the up coupled signal from all couplers, and being multiplexed on the way, capable transmitted signal sends OLT to.

Described OLT/ONU utilizes chaotic maps to produce a chaos sequence, the chaos sequence that produces is quantized, with the address code of the chaos sequence after quantizing as the OCDMA system;

Described OLT/ONU adopts the one-level logical mappings to produce chaos sequence, and described one-level logical mappings is:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described chaos sequence to generation is quantified as:

$a_n=\mathrm{sgn}\left(x_n\right)=\left\{\begin{array}{c}1,x_n\&GreaterEqual;0\\ -1,x_n<0\end{array}\right.,$ Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing;

Or,

Described OLT/ONU adopts the two-level logic mapping to produce chaos sequence, and described two-level logic is mapped as:

According to x _N+1=f (x _n)=γ x _n(1-x _n), with initial value x ₀The beginning iteration obtains real-valued chaos sequence { x _k, k=0,1,2 ..., select { x _k, k=0,1,2 ... the middle part score value as initial condition, according to $y_{n+1}=f\left(y_n\right)=\frac{a}{2}(\frac{{\mathrm{\&gamma;}}_2}{2}-1)-\frac{{\mathrm{\&gamma;}}_2}{a}{y^2}_n$ Generate chaos sequence, wherein, k is a sequence number, x _kBe the k item in the chaos sequence, n is a sequence number, y _nBe the n item in the chaos sequence, a is real number, γ ₂Be fractal parameter, 3.57＜γ ₂≤ 4;

Described OLT/ONU quantizes the chaos sequence that produces according to following formula:

$y_n=\underset{i=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{a}_i{2}^{-(i+1)}\&ap;2^{-L}\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=2^{-L}{Y}_n,$

Wherein, $Y_n=\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=(a_0{a}_1{a}_2\&CenterDot;\&CenterDot;\&CenterDot;a_i\&CenterDot;\&CenterDot;\&CenterDot;a_{L-1}),$ Wherein, by y _nThe sequence that forms is the chaos sequence after quantizing, a _i=0,1, L is real number.

The invention also discloses a kind of optical line terminal OLT, comprising: the first lambda router and more than one optical code division multiple access OCDMA group;

Each described OCDMA group comprises: the first optical transceiver, the first coupler and the first optical chaos codec more than;

At down direction, the first optical transceiver of each OCDMA group generates the descending light carrier of a wavelength, and wherein, the wavelength of the descending light carrier that the first optical transceiver of different OCDMA groups generates is different; In an OCDMA group, the descending light carrier that the first optical transceiver will generate is sent into more than one the first optical chaos codec; Each first optical chaos codec receives the descending light carrier from the first optical transceiver, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the first different in same OCDMA group optical chaos codecs are selected different address codes, and address code corresponding to this first optical chaos codec of the data that each first optical chaos codec will send to a user carried out being loaded into after the spread processing on the descending light carrier of reception and sent the first coupler to; The first coupler receives the descending light carrier of all the first optical chaos encoders in the same OCDMA group, sends into the first lambda router after being coupled into one tunnel descending coupled signal; Described the first lambda router receives the descending coupled signal from all the first couplers, is multiplexed into one tunnel descending transmitted signal and sends out;

At up direction, described the first lambda router receives up transmitted signal, up transmitted signal is carried out wavelength (de) multiplexing, obtain up single wavelength signals of an above different wave length, up single wavelength signals of a wavelength is sent to the first coupler of an OCDMA group, up single wavelength signals of different wave length sends to respectively the first coupler of different OCDMA groups; In an OCDMA group, the first coupler receives the up single wavelength signals from a wavelength of lambda router, this up single wavelength signals is shunted to up light receiving signal identical more than, sends each up light receiving signal to first an optical chaos codec; Each first optical chaos codec receives a up light receiving signal from the first coupler, up light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is sent into the first optical transceiver, and the first optical transceiver obtains the user by threshold judgement and sends data.

Described the first optical encoder comprises: chaos generator, quantization modules and coding module; Described chaos generator utilizes chaotic maps to produce a chaos sequence and sends to quantization modules; Quantization modules quantizes the chaos sequence that chaos generator produces, and the chaos sequence after quantizing is sent into coding module; Described coding module receives the chaos sequence after quantizing, with the address code of the chaos sequence after quantizing as the OCDMA system;

Described chaos generator adopts the one-level logical mappings to produce chaos sequence, described one-level logical mappings be:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described quantization modules is quantified as the chaos sequence that produces:

$a_n=\mathrm{sgn}\left(x_n\right)=\left\{\begin{array}{c}1,x_n\&GreaterEqual;0\\ -1,x_n<0\end{array}\right.,$ Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing;

Or,

Described chaos generator adopts the two-level logic mapping to produce chaos sequence, and described two-level logic is mapped as:

According to x _N+1=f (x _n)=γ x _n(1-x _n), with initial value x ₀The beginning iteration obtains real-valued chaos sequence { x _k, k=0,1,2 ..., select { x _k, k=0,1,2 ... the middle part score value as initial condition, according to $y_{n+1}=f\left(y_n\right)=\frac{a}{2}(\frac{{\mathrm{\&gamma;}}_2}{2}-1)-\frac{{\mathrm{\&gamma;}}_2}{a}{y^2}_n$ Generate chaos sequence, wherein, k is a sequence number, x _kBe the k item in the chaos sequence, n is a sequence number, y _nBe the n item in the chaos sequence, a is real number, γ ₂Be fractal parameter, 3.57＜γ ₂≤ 4;

Described quantization modules is quantified as the chaos sequence that produces:

$y_n=\underset{i=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{a}_i{2}^{-(i+1)}\&ap;2^{-L}\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=2^{-L}{Y}_n,$

Wherein, $Y_n=\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=(a_0{a}_1{a}_2\&CenterDot;\&CenterDot;\&CenterDot;a_i\&CenterDot;\&CenterDot;\&CenterDot;a_{L-1}),$ Wherein, by y _nThe sequence that forms is the chaos sequence after quantizing, a _i=0,1, L is real number.

The invention also discloses a kind of optical network unit ONU, comprising: the second optical chaos codec and the second optical transceiver;

At down direction, described the second optical chaos codec receives descending light receiving signal, and descending light receiving signal and the spectrum-spreading address code that presets are carried out computing, and operation result is sent into the second optical transceiver; The second optical transceiver obtains sending to self user's data by threshold judgement;

At up direction, described the second optical transceiver generates the up light carrier of a single wavelength and sends to the second optical chaos codec; The second optical chaos codec receives the up light carrier from the second optical transceiver, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that a user's the data to be sent is corresponding is carried out being loaded into after the spread processing on the up light carrier of reception and is sent out.

Described the second optical encoder comprises: chaos generator, quantization modules and coding module; Described chaos generator utilizes chaotic maps to produce a chaos sequence and sends to quantization modules; Quantization modules quantizes the chaos sequence that chaos generator produces, and the chaos sequence after quantizing is sent into coding module; Described coding module receives the chaos sequence after quantizing, with the address code of the chaos sequence after quantizing as the OCDMA system;

Described chaos generator adopts the one-level logical mappings to produce chaos sequence, described one-level logical mappings be:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described quantization modules is quantified as the chaos sequence that produces:

$a_n=\mathrm{sgn}\left(x_n\right)=\left\{\begin{array}{c}1,x_n\&GreaterEqual;0\\ -1,x_n<0\end{array}\right.,$ Wherein by a _nThe sequence that forms is the chaos sequence after quantizing;

Or,

Described chaos generator adopts the two-level logic mapping to produce chaos sequence, and described two-level logic is mapped as:

According to x _N+1=f (x _n)=γ x _n(1-x _n), with initial value x ₀The beginning iteration obtains real-valued chaos sequence { x _k, k=0,1,2 ..., select { x _k, k=0,1,2 ... the middle part score value as initial condition, according to $y_{n+1}=f\left(y_n\right)=\frac{a}{2}(\frac{{\mathrm{\&gamma;}}_2}{2}-1)-\frac{{\mathrm{\&gamma;}}_2}{a}{y^2}_n$ Generate chaos sequence, wherein, k is a sequence number, x _kBe the k item in the chaos sequence, n is a sequence number, y _nBe the n item in the chaos sequence, a is real number, γ ₂Be fractal parameter, 3.57＜γ ₂≤ 4;

Described quantization modules is quantified as the chaos sequence that produces:

$y_n=\underset{i=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{a}_i{2}^{-(i+1)}\&ap;2^{-L}\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=2^{-L}{Y}_n,$

Wherein, $Y_n=\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=(a_0{a}_1{a}_2\&CenterDot;\&CenterDot;\&CenterDot;a_i\&CenterDot;\&CenterDot;\&CenterDot;a_{L-1}),$ Wherein, by y _nThe sequence that forms is the chaos sequence after quantizing, a _i=0,1, L is real number.

By the foregoing invention content as seen, in PON communication means and system that the present invention proposes, at first adopt WDM technology that system bandwidth is carried out wavelength division multiplexing, generate a plurality of carrier wave set, each carrier wave set comprises a plurality of carrier waves of Same Wavelength, and wavelength differs from one another between each carrier wave set, and then adopts the OCDMA technology that the carrier wave of each wavelength is carried out code and divide, on each carrier wave, can distinguish different users according to address code again, therefore expand the user capacity in the PON system.And, in PON communication means and system that the present invention proposes, adopt Chaotic Spreading Spectrum Technology to produce the address code of OCDMA system, because it is strong that chaos is calculated randomness, therefore the address code quantity that obtains by Chaotic Spreading Spectrum Technology is large, enlarged each carrier wave has been carried out the number of codewords that code divides, thereby expanded the user capacity of PON system.

Description of drawings

Fig. 1 is the flow chart of embodiment of the invention PON communication means;

Fig. 2 is the structural representation of embodiment of the invention PON system.

Embodiment

In order to make the purpose, technical solutions and advantages of the present invention clearer, describe the present invention below in conjunction with the drawings and specific embodiments.

Basic thought of the present invention is: at first adopt WDM technology that system bandwidth is carried out wavelength division multiplexing, obtain a plurality of carrier waves of different wave length, and then adopt optical code division multiple access (OCDMA) technology that the carrier wave of each wavelength is carried out code and divide, in each carrier wave, embed one group of OCDMA user, and adopt Chaotic Spreading Spectrum Technology to produce the address code of OCDMA system.For example, wavelength division multiplexing is take N carrier wave as example, and its wavelength is respectively λ ₁, λ ₂..., λ _N, OCDMA is take M code as example, and coding is respectively C ₁, C ₂..., C _M, by (λ, C) this two dimension amount the user is distinguished, therefore expanded the user capacity of system.

At first by a specific embodiment PON communication means that the present invention proposes is described.Fig. 1 is the flow chart of embodiment of the invention PON communication means.As shown in Figure 1, the PON communication means of embodiment of the invention proposition comprises the steps:

Step 101: transmitting terminal generates more than one light carrier group, and wherein each light carrier group comprises the more than one light carrier that wavelength is identical, and the wavelength of the light carrier that different light carrier groups comprise is different.

Step 102: transmitting terminal adopts Chaotic Spreading Spectrum Technology to generate the address code of optical code division multiple access (OCDMA) system, the address code that the data that sends to a user is corresponding carries out being loaded on the light carrier after the spread processing, adopt the address code difference corresponding to each user of Same Wavelength transmission, namely adopt respectively different address codes to load the data of different user on each light carrier in the same light carrier group.

Step 103: transmitting terminal is coupled into one road coupled signal with all light carriers in the same light carrier group.

Step 104: transmitting terminal is multiplexed into transmitted signal with the coupled signal of all light carrier groups and sends to receiving terminal.

Step 105: receiving terminal receives transmitted signal, and transmitted signal is carried out wavelength (de) multiplexing, obtains single wavelength signals of an above different wave length.

Step 106: single wavelength signals of each wavelength is shunted to light receiving signal identical more than.

Step 107: each light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is carried out threshold judgement, obtain user data.In this step, address code corresponding to each user is complementary when requiring the spectrum-spreading address code preset and encoding.A kind of better operation method is that each light receiving signal and the spectrum-spreading address code that presets are carried out related operation.

Because the as a result randomness of chaotic computing is strong, if therefore chaotic computing is applied to coding, can obtain more available codeword, so in above-mentioned PON communication means, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system.Its detailed process is as follows: utilize chaotic maps to produce a chaos sequence; The chaos sequence that produces is quantized; With the address code of the chaos sequence after quantizing as the OCDMA system.

Wherein, generation and quantification chaos sequence specifically can adopt following two kinds of methods:

First method: adopt one-level logic (Logistic) mapping.

At first, adopt the one-level logical mappings to produce chaos sequence.

Described one-level logical mappings is:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4.When system is in chaos state, by sequence aperiodic, the non-convergence, very responsive to initial value of its generation.γ and initial value x ₀Determined the difference of sequence.

Correspondingly, the chaos sequence that produces is quantified as:

$a_n=\mathrm{sgn}\left(x_n\right)=\left\{\begin{array}{c}1,x_n\&GreaterEqual;0\\ -1,x_n<0\end{array}\right.,$ Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing.

Second method: adopt the two-level logic mapping.Because the real-valued sequence that single chaotic maps produces is limited, for avoiding this situation, a plurality of chaotic maps can be cascaded up the chaos sequence that generating period is longer.Only be mapped as example with two-level logic herein.

At first, adopt the two-level logic mapping to produce chaos sequence.

Described two-level logic is mapped as:

According to x _N+1=f (x _n)=γ x _n(1-x _n), with initial value x ₀The beginning iteration obtains real-valued chaos sequence { x _k, k=0,1,2 ..., select { x _k, k=0,1,2 ... the middle part score value as initial condition, according to $y_{n+1}=f\left(y_n\right)=\frac{a}{2}(\frac{{\mathrm{\&gamma;}}_2}{2}-1)-\frac{{\mathrm{\&gamma;}}_2}{a}{y^2}_n$ Generate chaos sequence, wherein, k is a sequence number, x _kBe the k item in the chaos sequence, n is a sequence number, y _nBe the n item in the chaos sequence, a is real number, γ ₂Be fractal parameter, 3.57＜γ ₂≤ 4.

Correspondingly, the chaos sequence that produces is quantified as:

$y_n=\underset{i=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{a}_i{2}^{-(i+1)}\&ap;2^{-L}\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=2^{-L}{Y}_n,$

Wherein, $Y_n=\underset{i=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{a}_i{2}^{(L-1)-i}=(a_0{a}_1{a}_2\&CenterDot;\&CenterDot;\&CenterDot;a_i\&CenterDot;\&CenterDot;\&CenterDot;a_{L-1}),$ Wherein, by y _nThe sequence that forms is the chaos sequence after quantizing, a _i=0,1, L is real number.

The above PON communication means that the present invention is proposed is illustrated, adopt above-mentioned communication means, also need the structure of PON system and OLT and ONU is improved accordingly, the below introduces the PON system that the present invention proposes, and the OLT that adopts in the PON system and ONU.

The PON system that the present invention proposes comprises: transmitting terminal and receiving terminal.

Transmitting terminal generates more than one light carrier group, and each light carrier group comprises the more than one light carrier that wavelength is identical, and wherein, the wavelength of the light carrier that different light carrier groups comprise is different.Transmitting terminal adopts Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that the data that sends to a user is corresponding carries out being loaded on the light carrier after the spread processing, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission.Transmitting terminal is coupled into one road coupled signal with all light carriers in the same light carrier group, and the coupled signal of all light carrier groups is multiplexed into transmitted signal sends to receiving terminal.

Receiving terminal receives transmitted signal, transmitted signal is carried out wavelength (de) multiplexing, obtain single wavelength signals of an above different wave length, single wavelength signals of each wavelength is shunted to light receiving signal identical more than, each light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is carried out threshold judgement, obtain user data.

The OLT and the ONU that adopt in the concrete composition structure of the PON system that next the present invention is proposed with two specific embodiments describing the up-downgoing transmission respectively and the PON system describe.Fig. 2 is the structural representation of embodiment of the invention PON system.PON system configuration in two specific embodiments all as shown in Figure 2, the PON system in the embodiment of the invention comprises: OLT 21, lambda router 22, more than one coupler 23 and more than one ONU 24.Lambda router 22 1 ends link to each other with OLT 21, and the other end links to each other respectively with more than one coupler 23; Each coupler 23 1 end links to each other with lambda router 22, and the other end links to each other with part ONU 24 among all ONU24; Each ONU24 only connects a coupler 23.

Wherein, OLT 21 comprises: more than one OCDMA group the 210 and first lambda router 211.Each OCDMA group 210 comprises: the first optical transceiver 2101, the first optical chaos codec 2101 and the first coupler 2103 more than one.

Each ONU 24 comprises: the second optical chaos codec 241 and the second optical transceiver 242.

In first embodiment, as an example of the downlink transfer of PON system example each part in the system is described.In PON system shown in Figure 2, at down direction, OLT21 is as transmitting terminal; Receiving terminal comprises: lambda router 22, more than one coupler 23 and more than one ONU24.

In OLT 21, the first optical transceiver 2101 of each OCDMA group 210 generates the descending light carrier of a wavelength, and the wavelength of the descending light carrier that the first optical transceiver 2101 of different OCDMA groups 210 generates respectively is different.In an OCDMA group 210, the descending light carrier that the first optical transceiver 2101 will generate is sent into more than one the first optical chaos codec 2102.The descending light carrier that each first optical chaos codec 2102 receives from the first optical transceiver 2101 adopts Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system.Same OCDMA organizes the address code difference that 210 interior the first different optical chaos codecs 2102 generate.After user's the address code that each first optical chaos codec 2102 will send to these the first optical chaos codec 2102 correspondences of the data of a user is carried out spread processing, be loaded on the descending light carrier of reception, send the first coupler 2103 to.Wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission.The first coupler 2103 receives the descending light carrier of all the first optical chaos encoders 2102 in the same OCDMA group 210, sends into the first lambda router 211 after being coupled into one tunnel descending coupled signal.The descending coupled signal that the first lambda router 211 receives from all the first couplers 2103 is multiplexed into one tunnel descending transmitted signal and sends lambda router 22 to.

The descending transmitted signal that lambda router 22 receives from OLT 21, descending transmitted signal is carried out wavelength (de) multiplexing, obtain descending single wavelength signals of an above different wave length, descending single wavelength signals of a wavelength is sent to a coupler 23, and descending single wavelength signals of different wave length sends to respectively different coupler 23.

Descending single wavelength signals that each coupler 23 receives from a wavelength of lambda router 22 is carried out shunt to this descending single wavelength signals, obtains descending light receiving signal identical more than, sends each descending light receiving signal to an ONU 24.

In each ONU 24, the descending light receiving signal that the second optical chaos codec 241 receives from coupler 23, descending light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is sent into the second optical transceiver 242, the second optical transceivers 242 obtain sending to self user by threshold judgement data.A kind of better execution mode is that 241 pairs of descending light receiving signals of the second optical chaos codec carry out related operation with the spectrum-spreading address code that presets.

In second embodiment, as an example of the uplink of PON system example each part in the system is described.In PON system shown in Figure 2, at up direction, transmitting terminal comprises more than one ONU 24, more than one coupler 23 and lambda router 22; Receiving terminal comprises OLT 21.

In each ONU 24, the second optical transceiver 242 generates the up light carrier of a single wavelength and sends to the second optical chaos codec 241.Wherein, all ONU 24 that link to each other with same coupler 23 consist of a up light carrier group, and the wavelength of the uplink optical signal that their the second optical transceiver 242 generates is identical; The wavelength of the uplink optical signal that the second optical transceiver 242 of the ONU 24 that links to each other from different couplers 23 generates is different.The up light carrier that the second optical chaos codec 241 receives from the second optical transceiver 242, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that a user's the data to be sent is corresponding is carried out being loaded into after the spread processing on the up light carrier of reception and is sent coupler 23 to.Wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission, the second optical chaos codec 241 of the ONU 24 that therefore links to each other from same coupler 23 adopts different address codes.

Each coupler 23 receives the up light carrier of all the second optical chaos codecs 241 that link to each other, and is coupled on the way and sends into lambda router 22 behind the capable coupled signal.

The up coupled signal that lambda router 22 receives from all couplers 23, being multiplexed on the way, capable transmitted signal sends OLT 21 to.

In OLT 21, the up transmitted signal that the first lambda router 211 receives from lambda router 22, up transmitted signal is carried out wavelength (de) multiplexing, obtain up single wavelength signals of an above different wave length, up single wavelength signals of a wavelength is sent to first coupler 2103.Up single wavelength signals of different wave length sends to respectively the first coupler 2103 of different OCDMA groups.In an OCDMA group 210, up single wavelength signals that the first coupler 2103 receives from a wavelength of the first lambda router 211, this up single wavelength signals is carried out shunt, obtain up light receiving signal identical more than, send each up light receiving signal to first an optical chaos codec 2102.The up light receiving signal that each first optical chaos codec 2102 receives from the first coupler 2103, up light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is sent into the first optical transceiver 2101, the first optical transceivers 2101 send data by threshold judgement acquisition user.A kind of better execution mode is that 2102 pairs of up light receiving signals of the first optical chaos codec carry out related operation with the spectrum-spreading address code that presets.

In PON system shown in Figure 2, the first optical chaos codec 2101 among the OLT 21 and the second optical chaos codec 241 among the ONU 24 all adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, carry out the OCDMA coding.The internal structure of the first optical encoder 2101 and the second optical chaos codec 241 all comprises at least: chaos generator, quantization modules and coding module.Chaos generator utilizes chaotic maps to produce a chaos sequence and sends to quantization modules; Quantization modules quantizes the chaos sequence that chaos generator produces, and the chaos sequence after quantizing is sent into coding module; Described coding module receives the chaos sequence after quantizing, with the address code of the chaos sequence after quantizing as the OCDMA system.

Wherein, chaos generator can adopt the mapping of one-level logical mappings or two-level logic or more senior logical mappings to produce chaos sequence, and is identical in concrete implementation and the previous embodiment, do not repeat them here.

By above embodiment as seen, in PON communication means and system that the present invention proposes, at first adopt WDM technology that system bandwidth is carried out wavelength division multiplexing, generate a plurality of carrier wave set, each carrier wave set comprises a plurality of carrier waves that wavelength is identical, and the wavelength of each carrier wave set differs from one another, and then adopts the OCDMA technology that the carrier wave of each wavelength is carried out code and divide, on each carrier wave, can distinguish different users according to address code again, therefore expand the user capacity in the PON system.And, in PON communication means and system that the present invention proposes, adopt Chaotic Spreading Spectrum Technology to produce the address code of OCDMA system, because the randomness of chaos result of calculation is strong, therefore the address code quantity that obtains by Chaotic Spreading Spectrum Technology is large, enlarged each carrier wave has been carried out the optional number of codewords of yard timesharing, thereby expanded the user capacity of PON system.

The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, is equal to replacement, improvement etc., all should be included within the scope of protection of the invention.

Claims (6)

1. a passive optical network PON communication means is characterized in that, the method comprises:

Transmitting terminal generates more than one light carrier group, and each light carrier group comprises the more than one light carrier that wavelength is identical, and wherein, the wavelength of the light carrier that different light carrier groups comprise is different;

Transmitting terminal adopts Chaotic Spreading Spectrum Technology to generate the address code of optical code division multiple access OCDMA system, the address code that the data that sends to a user is corresponding carries out being loaded on the light carrier after the spread processing, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission;

Transmitting terminal is coupled into one road coupled signal with all light carriers in the same light carrier group, and the coupled signal of all light carrier groups is multiplexed into transmitted signal sends to receiving terminal;

Receiving terminal receives transmitted signal, and transmitted signal is carried out wavelength (de) multiplexing, obtains single wavelength signals of an above different wave length;

Receiving terminal is shunted to light receiving signal identical more than with single wavelength signals of each wavelength, and each light receiving signal and the spectrum-spreading address code that presets are carried out computing, and operation result is carried out threshold judgement, obtains user data;

Wherein, the described employing Chaotic Spreading Spectrum Technology address code that generates the OCDMA system comprises: utilize chaotic maps to produce a chaos sequence; The chaos sequence that produces is quantized; With the address code of the chaos sequence after quantizing as the OCDMA system; Wherein, the described chaos sequence of chaotic maps generation that utilizes is:

Adopt the one-level logical mappings to produce chaos sequence; Described one-level logical mappings is:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described chaos sequence to generation is quantified as:

Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing.

2. a passive optical network PON system is characterized in that, comprising: transmitting terminal and receiving terminal;

Described transmitting terminal generates more than one light carrier group, each light carrier group comprises the more than one light carrier that wavelength is identical, wherein, the wavelength of the light carrier that different light carrier groups comprise is different, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that the data that sends to a user is corresponding carries out being loaded on the light carrier after the spread processing, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission, all light carriers in the same light carrier group are coupled into one road coupled signal, and the coupled signal of all light carrier groups is multiplexed into transmitted signal sends to receiving terminal;

Described receiving terminal receives transmitted signal, transmitted signal is carried out wavelength (de) multiplexing, obtain single wavelength signals of an above different wave length, single wavelength signals of each wavelength is shunted to light receiving signal identical more than, each light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is carried out threshold judgement, obtain user data, wherein

Described transmitting terminal comprises optical line terminal OLT or optical network unit ONU, and described OLT/ONU utilizes chaotic maps to produce a chaos sequence, the chaos sequence that produces is quantized, with the address code of the chaos sequence after quantizing as the OCDMA system;

Described OLT/ONU adopts the one-level logical mappings to produce chaos sequence, and described one-level logical mappings is:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described chaos sequence to generation is quantified as:

Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing.

3. PON according to claim 2 system is characterized in that,

Described transmitting terminal comprises: optical line terminal OLT;

Described receiving terminal comprises: lambda router, more than one coupler and an above optical network unit ONU;

Described lambda router receives the descending transmitted signal from OLT, descending transmitted signal is carried out wavelength (de) multiplexing, obtain descending single wavelength signals of an above different wave length, descending single wavelength signals of a wavelength is sent to a coupler, and descending single wavelength signals of different wave length sends to respectively different couplers;

Each coupler receives the descending single wavelength signals from a wavelength of lambda router, and this descending single wavelength signals is shunted to descending light receiving signal identical more than, and a descending light receiving signal is sent to an ONU;

Each ONU receives a descending light receiving signal, and descending light receiving signal and the spectrum-spreading address code that presets are carried out computing, and operation result is carried out threshold judgement, obtains sending to self user's data.

4. PON according to claim 2 system is characterized in that,

Described transmitting terminal comprises: lambda router, more than one coupler and more than one optical network unit ONU; Described lambda router links to each other respectively with more than one coupler; Each coupler links to each other with part ONU among all ONU, and each ONU only connects a coupler;

Described receiving terminal comprises: optical line terminal OLT;

Described each ONU generates the up light carrier of a single wavelength, the more than one up light carrier group of the common generation of all ONU, wherein, the up optical carrier wavelength that the different ONU that links to each other from same coupler generates is identical, consist of a up light carrier group, the wavelength of the up light carrier that different up light carrier groups comprises is different; Each ONU adopts Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that a user's the data is corresponding is carried out being loaded on the up light carrier after the spread processing and is sent coupler to, wherein, adopt the address code difference corresponding to each user of Same Wavelength transmission;

Each coupler is coupled into all the up light carriers in the up light carrier group on the way, and capable coupled signal sends to lambda router;

Described lambda router receives the up coupled signal from all couplers, and being multiplexed on the way, capable transmitted signal sends OLT to.

5. an optical line terminal OLT is characterized in that, comprising: the first lambda router and more than one optical code division multiple access OCDMA group;

Each described OCDMA group comprises: the first optical transceiver, the first coupler and the first optical chaos codec more than;

At down direction, the first optical transceiver of each OCDMA group generates the descending light carrier of a wavelength, and wherein, the wavelength of the descending light carrier that the first optical transceiver of different OCDMA groups generates is different; In an OCDMA group, the descending light carrier that the first optical transceiver will generate is sent into more than one the first optical chaos codec; Each first optical chaos codec receives the descending light carrier from the first optical transceiver, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the first different in same OCDMA group optical chaos codecs are selected different address codes, and address code corresponding to this first optical chaos codec of the data that each first optical chaos codec will send to a user carried out being loaded into after the spread processing on the descending light carrier of reception and sent the first coupler to; The first coupler receives the descending light carrier of all the first optical chaos encoders in the same OCDMA group, sends into the first lambda router after being coupled into one tunnel descending coupled signal; Described the first lambda router receives the descending coupled signal from all the first couplers, is multiplexed into one tunnel descending transmitted signal and sends out;

At up direction, described the first lambda router receives up transmitted signal, up transmitted signal is carried out wavelength (de) multiplexing, obtain up single wavelength signals of an above different wave length, up single wavelength signals of a wavelength is sent to the first coupler of an OCDMA group, up single wavelength signals of different wave length sends to respectively the first coupler of different OCDMA groups; In an OCDMA group, the first coupler receives the up single wavelength signals from a wavelength of lambda router, this up single wavelength signals is shunted to up light receiving signal identical more than, sends each up light receiving signal to first an optical chaos codec; Each first optical chaos codec receives a up light receiving signal from the first coupler, up light receiving signal and the spectrum-spreading address code that presets are carried out computing, operation result is sent into the first optical transceiver, and the first optical transceiver obtains the user by threshold judgement and sends data

Wherein, described the first optical chaos codec comprises: chaos generator, quantization modules and coding module; Described chaos generator utilizes chaotic maps to produce a chaos sequence and sends to quantization modules; Quantization modules quantizes the chaos sequence that chaos generator produces, and the chaos sequence after quantizing is sent into coding module; Described coding module receives the chaos sequence after quantizing, with the address code of the chaos sequence after quantizing as the OCDMA system;

Described chaos generator adopts the one-level logical mappings to produce chaos sequence, and described one-level logical mappings is:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described quantization modules is quantified as the chaos sequence that produces:

Wherein, by a _nThe sequence that forms is the chaos sequence after quantizing.

6. an optical network unit ONU is characterized in that, comprising: the second optical chaos codec and the second optical transceiver;

At down direction, described the second optical chaos codec receives descending light receiving signal, and descending light receiving signal and the spectrum-spreading address code that presets are carried out computing, and operation result is sent into the second optical transceiver; The second optical transceiver obtains sending to self user's data by threshold judgement;

At up direction, described the second optical transceiver generates the up light carrier of a single wavelength and sends to the second optical chaos codec; The second optical chaos codec receives the up light carrier from the second optical transceiver, adopt Chaotic Spreading Spectrum Technology to generate the address code of OCDMA system, the address code that a user's the data to be sent is corresponding is carried out being loaded into after the spread processing on the up light carrier of reception and is sent out;

Wherein, described the second optical chaos codec comprises: chaos generator, quantization modules and coding module; Described chaos generator utilizes chaotic maps to produce a chaos sequence and sends to quantization modules; Quantization modules quantizes the chaos sequence that chaos generator produces, and the chaos sequence after quantizing is sent into coding module; Described coding module receives the chaos sequence after quantizing, with the address code of the chaos sequence after quantizing as the OCDMA system;

Described chaos generator adopts the one-level logical mappings to produce chaos sequence, described one-level logical mappings be:

x _N+1=f (x _n)=γ x _n(1-x _n), wherein, n is a sequence number, x _nBe the n item in the chaos sequence, γ is fractal parameter, 3.57＜γ≤4;

Described quantization modules is quantified as the chaos sequence that produces:

Wherein by a _nThe sequence that forms is the chaos sequence after quantizing.

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