CN110233701A - Wirelessly communicate the decoding method of physical layer communication safety - Google Patents
Wirelessly communicate the decoding method of physical layer communication safety Download PDFInfo
- Publication number
- CN110233701A CN110233701A CN201910442318.8A CN201910442318A CN110233701A CN 110233701 A CN110233701 A CN 110233701A CN 201910442318 A CN201910442318 A CN 201910442318A CN 110233701 A CN110233701 A CN 110233701A
- Authority
- CN
- China
- Prior art keywords
- bit
- receiving end
- message
- code word
- llr value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
- H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
- H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
- H03M13/11—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits using multiple parity bits
- H03M13/1102—Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
- H03M13/1105—Decoding
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0056—Systems characterized by the type of code used
- H04L1/0061—Error detection codes
Abstract
The invention proposes a kind of decoding methods for wirelessly communicating physical layer communication safety, can significantly reduce the probability that information is stolen using the present invention.The technical scheme is that: transmitting terminal encodes message bit sequence using LDPC encoder, bit XOR operation is carried out to the partial bit of the adjacent code word of transmitting terminal and obtains new bit sequence, BPSK modulator is by newly-generated bit and to have neither part nor lot in the check bit bit modulation of operation be that BPSK symbol is sent to receiving end；The codeword message position prior information and channel that receiving end BPSK demodulator is fed back according to receiving end ldpc decoder receive symbol, demodulate the log-likelihood ratio LLR value of code word check bit；Receiving end ldpc decoder calculates message digit LLR value, decodes out the message digit of current code word, and codeword message position LLR value is fed back to receiving end BPSK demodulator, and such iteration goes on, the message digit until decoding out all code words.
Description
Technical field
The present invention relates to information theory security fields, especially communication information security technology, are mainly used for channel radio
Believe physical layer, ensures low-density checksum (LDPC) decoding method of physical layer communication safety.
Background technique
As the development speed of computer information technology is increasingly accelerated, traditional wire communication is gradually wirelessly communicated and is replaced
Generation.Wireless communication is as current mainstream communication mode, and there are some potential safety problemss for open communication mode, to entire
The safety of communication brings biggish threat.In a wireless communication system, the broadcast characteristic and wireless channel that electromagnetic signal is propagated
Open nature make any user in a certain range all have receive wireless transmission signal ability.Due to wireless communication
The channel open of middle transmission medium, signal are arbitrarily propagated in space by radio wave, lose the constraint of " wired ".Electricity
Electromagnetic wave propagation loses barrier, this information for causing wireless signal to carry is easier to be ravesdropping, and listener-in does not need very high skill
Art or equipment can obtain the communication information.At this stage, disparate networks audiomonitor and monitoring means are to communications security and secrecy
Property bring serious loss, be related to business and the secure wireless communication problem of military secrecy become more and more important.According to working as
Preceding information technology feature, communication construction can be divided into this five layer frame of application layer, transport layer, network layer, MAC layer and physical layer
Structure.In traditional information communication, relevant safety protection technique is usually all disposed in the above contour level level of MAC layer.It passes
System method ensures the confidentiality and safety communicated frequently with the mode of communication encryption.At this stage, safety of physical layer is protected
Attention dynamics will be markedly less than communication construction high level.The safety protection technique that physical layer uses is mainly by handling channel
And protection, to ensure the safety and confidentiality of communication channel.The effect of physical layer is to convert the information into suitable wireless channel
The form of transmission.Transmitting terminal mainly includes the functional modules such as channel coding, digital modulation, baseband postprocessing, radio-frequency modulations, is received
The signal received is restored at end accordingly, mainly includes radio demodulating, synchronization and channel estimation, digital demodulation, channel
The functional modules such as decoding.It is each due to being widely present in the opening of wireless channel, broadcast and fading and wireless channel
Noise and interference are planted, the perfect channel of the so-called error free transmission of channel between enciphering/deciphering is often difficult to set up.It is wirelessly communicating
In also tend to be difficult to ensure for the safe lane of cipher key delivery.Therefore, when physical layer is unreliable, only with conventional cryptography machine
The safety of the system of system will be declined.If physical layer is fully transparent to listener-in, listener-in easily passes through wireless channel pair
It transmits information and carries out illicit reception.Once listener-in decodes out or has known the close of upper layer information enciphering/deciphering by other approach
Key will seriously threaten communication security.It is unstable due to the intrinsic broadcast of radio communication channel, opening and transmission link
Property so that wireless communication system compared to traditional wired communication system be more easier the investigation by illegal user, intercept and capture and
It monitors, brings transmission data secret leaking problem.Traditional secrecy means utilize mainly using contemporary cryptology as theoretic basis
Encryption Algorithm and cipher key pair information are encrypted.Traditional Encryption Algorithm is mostly based on existing computer can not be in asking in short-term
It is cracked.But with the fast development of computer computation ability and possess the rapid Factorization for executing flood tide complexity
The appearance of the quantum computer of ability, many traditional encryption methods will be no longer reliable.In addition, traditional block cipher or
Public private key encryption technology often has very high computational complexity and delay, and encryption and decryption is difficult to asking interior completion in short-term, is difficult full
The requirement of sufficient communication delay.
Safe coding technology is a kind of physical layer commonly security technique, is mainly to ensure that connection net in this way
The legitimate user of network can obtain reliable and safety communication channel.If illegal user than legitimate user channel condition more
Difference, then illegal user can not obtain in channel can identification information.Safety of physical layer coding is the basis for realizing safe transmission,
It avoids information from being ravesdropping by the difference of the main channel quality for stealing channel from the angle of information theory.In main channel transmission quality
When better than tapping channel transmission quality, it can theoretically ensure perfect safe transmission；On the other hand, pass through signal processing hand
Section, the various resources that can effectively integrate wireless communication system are come, and steal interchannel using the main otherness for stealing link to break up master
Communication quality difference, provide solid foundation for the realization of safe coding.Safe coding technical application feelings from current various countries
From the point of view of condition, currently in the world there are many kinds of the channel coding of class, common channel coding has polarization code, Turbo code and low close
Even-odd check LDPC code etc. is spent, these channel codings adaptability certain in the upper change appropriate of application can be relatively easy to
Reach the secrecy capacity limit.Other than several common safe codings mentioned above, there are also compile when some algebra precodings, sky
Code etc. can have certain safety protection function to secure communication.At this stage, ensure that the major measure of secure wireless communication has
Two classes.First kind method is the high level in open system interconnection (Open System Interconnection, OSI) model
Encipher-decipher method is designed, safety is promoted by encryption mechanism, prevents listener-in from stealing secret information.But this safety approach face it is logical
Letter delay is longer, encryption and decryption expense is big and Encryption Algorithm is cracked the problems such as failing.Second class method is set in physical layer
Reasonable communications scheme is counted, the supplement or substitute technology as upper layer encryption method.It is legal that safety of physical layer method utilizes
The intrinsic difference of channel quality between channel and tapping channel, prevents private information to be ravesdropping from information level.
Wireless communication safety of physical layer covers technological means abundant, can play very to the promotion of security of system
Important role.Common metric parameter of the signal-to-noise ratio (SNR) as assessment channel quality can be used to assess main channel and eavesdropping
Difference in channel quality between channel.If the SNR of main channel is SNRBAnd corresponding bit error rate (BER) is PB, tapping channel
SNR be SNREAnd corresponding BER is PE.In order to guarantee the reliability and safety of information, the following conditions need to be met
Wherein,To meet highest BER value needed for the transmission of main channel reliable communications, (set up is 10-5, BER becomes in main channel
It is bordering on 0, indicates that transmitted bit is almost properly received, authorization both sides can communicate normally, meet authorization intercommunication reliability
Requirement),To meet the required minimum bit error rate BER value of tapping channel communication security transmission, (setting up is 0.49, eavesdropping
BER levels off to 0.5 in channel, receives sequence and is similar to random sequence, listener-in can not steal secret information, and meet wanting for communications security
It asks).Main channel bit error rate BER isWhen corresponding bit error rate SNR be SNRB,min, tapping channel bit error rate BER isWhen corresponding SNR be SNRE,max。
Conventional encoder code method reaches the mesh of protection classified information by punching low-density checksum LDPC code message digit
's.In receiving end, message bit sequence is encoded using system type low-density checksum LDPC code.Then, disappearing code word
It punches and remaining check bit position is modulated to biphase phase shift keying BPSK symbol and is sent in breath position.In receiving end,
BPSK demodulator recalls log-likelihood ratio (LLR) value of check bit according to the symbolic solution received.Ldpc decoder is by message digit
LLR value be initialized as 0, and the posteriority LLR value of message digit is calculated using belief propagation algorithm according to check bit LLR value, from
And estimate message bit sequence.The corresponding bit error rate BER curve of the coding and decoding method of physical layer communication safety has sharp
Characteristic, i.e., when SNR value is more than a threshold value, bit error rate BER can happen suddenly steep drop.It is special that conventional encoder code method does not have this
Property, therefore the ability for reducing safety clearance is limited, the application scenarios of adaptation are limited.
Summary of the invention
The deficiency of safety clearance ability is reduced in order to solve conventional encoder code method, the present invention proposes a kind of in the main letter of guarantee
Under the premise of road normal communication, it can reduce the probability that information is stolen with improving information safety, significant decrease main channel and steal
Listen the decoding method of the wireless communication physical layer communication safety of safety clearance between channel (SNRgap).
Above-mentioned purpose of the invention can be obtained by following measures, a kind of volume wirelessly communicating physical layer communication safety
Coding/decoding method has following technical characteristic: wireless communication transmitting terminal encodes message bit sequence using LDPC encoder,
And code word is divided into message digit and check bit two parts, bit XOR operation is carried out to the partial bit of the adjacent code word of transmitting terminal,
Obtain new bit sequence；Sequence is handled by serioparallel exchange, using transmitting terminal BPSK modulator by newly-generated bit
And the check bit bit modulation of operation is had neither part nor lot in as BPSK symbol and is sent to receiving end；Receiving end is according to the BPSK received
The priori log-likelihood ratio LLR value of symbol and preamble code word message digit, demodulates the log-likelihood ratio LLR value of code word check bit,
And the log-likelihood ratio LLR value of the code word check bit is passed into receiving end ldpc decoder；Receiving end ldpc decoder is by code
The log-likelihood ratio LLR value of word message digit is initialized as 0, and the posteriority pair of the codeword message position is calculated using belief propagation algorithm
Number likelihood ratio LLR value, and the LLR value of the codeword message position is passed into receiving end BPSK demodulator；Receiving end BPSK demodulator
Symbol is received according to the codeword message position prior information of receiving end ldpc decoder feedback and channel, to next code word check bit
Log-likelihood ratio LLR value demodulated, obtain the log-likelihood ratio LLR value of check bit and pass to receiving end LDPC decoding
Device, receiving end ldpc decoder and the mutual iteration interactive information of demodulator, such iteration goes on, until decoding out all codes
The message digit of word completes entire demodulation coding process.
The present invention has the advantages that.
The work of BPSK demodulator is had two parts by the present invention, carries out bit XOR operation to preamble code word message digit
Check bit, the preamble code word message digit prior information and channel that BPSK demodulator is fed back according to ldpc decoder receive symbol, meter
Calculate the LLR value of check bit.In the case where main channel authorization intercommunication channel quality is constant, coding and decoding proposed by the present invention
Method will not change the communication quality of authorization both sides.However, when listener-in demodulates code word check bit by tapping channel, due to
Tapping channel quality is worse and demodulates the prior information for needing preamble code word, and demodulation effect can be worse and causes to decode effect more
Difference.Therefore, method proposed by the present invention can not influence to authorize both sides' normal communication, not change main channel and tapping channel
Under the premise of channel quality, the communication quality of listener-in can obviously reduce, reach the purpose of physical layer communication safety.
Partial bit between multi-code word is coupled in transmitting terminal and carries out the processing of bit exclusive or, changes in receiving end by the present invention
For demodulation coding.BPSK demodulator receives symbol according to channel and preamble code word prior information calculates check bit LLR value.LDPC
Message digit LLR value is initialized as 0 by decoder, and calculates message digit using belief propagation algorithm according to check bit LLR value
Posteriority log-likelihood ratio LLR value, to estimate message bit sequence.This design method can be with sharpening BER curve, effectively
Reduce safety clearance.Shield of trying hard to keep is formed with during wireless transmission to upper layer encryption information, effectively prevents listener-in by stealing
It listens channel illegally to obtain useful information, the difficulty by wireless channel eavesdropping and breaking encryption information is greatly improved, significantly increases
The safety of wireless communication.
The present invention designs a kind of iterative demodulation interpretation method in receiving end, successively each code word of demodulation coding.For working as
Preceding code word, BPSK demodulator estimate the logarithm of the code word check bit first with the prior information and reception signal of preamble code word
Likelihood ratio LLR value.Then, the LLR value of message digit is initialized as 0 by ldpc decoder.According to the LLR value of check bit, LDPC is translated
Code device calculates the posteriority LLR value of message digit using belief propagation algorithm, to obtain binary message bit sequence, completes this code
The decoding of word.It is different from conventional encoder code method, for each coding codeword, the part check bit of the code word first with preamble
The message digit of word carries out bit XOR operation, then by the bit modulation after calculating is symbol.Operation is had neither part nor lot in for remaining
Check bit is directly modulated to symbol.Therefore, coding and decoding method proposed by the present invention makes the presence of connection, a code between code word
The decoding failure of word will affect the decoding of subsequent codewords.This coding and decoding method is unfavorable for the eavesdropping with more poor channel quality
Person.Compared to conventional encoder code method, safety clearance needed for method proposed by the present invention is lower, can be adapted for more wireless
Communication scenes.
Refering to Fig. 4.Coding and decoding method and conventional encoder code method provided by the invention carries out BER performance and compares.In emulation
LDPC code code rate is 0.25, code length 3940, and belief propagation algorithm maximum number of iterations is 200.Compared with traditional decoding algorithm,
The BER curve of coding and decoding method of the present invention is more precipitous.Main letter can be significantly reduced using coding and decoding method provided by the invention
Safety clearance (SNRgap) between road and tapping channel, and reduce information under the premise of guaranteeing main channel normal communication and be stolen
The probability taken, improving information safety.
Refering to Fig. 5.Coding and decoding method and conventional encoder code method provided by the invention carries out safety clearance performance and compares.It is imitative
Very middle LDPC code code rate is 0.25, code length 3940, and belief propagation algorithm maximum number of iterations is 200.The BER threshold value of listener-inIt is 0.49, main channel BER threshold valueIt is 10-5.The SNR value of fixed main channel, as main channel and tapping channel SNR are poor
The SNR value of the increase of value, tapping channel gradually decreases.Under identical SNR difference, compared with traditional decoding algorithm, the present invention is compiled
The BER performance that interpretation method corresponds to listener-in is worse, thus has higher communications security.As code word number ρ=20, this
Safety clearance is reduced to 4.6dB from 9.3dB needed for conventional encoder code method by invention coding and decoding method.
Detailed description of the invention
The following further describes the present invention with reference to the drawings.
Fig. 1 is that solution message processing flow figure is compiled safely in present invention wireless communication physical layer transmitting terminal and receiving end.
Fig. 2 is the schematic diagram that Fig. 1 transmitting terminal carries out bit XOR operation to the partial bit of multiple code words.
Fig. 3 is the schematic diagram of bit error rate BER curve of the present invention and safety clearance.
Fig. 4 is the receiving end bit error rate BER curve figure that simulating, verifying of the present invention obtains.
Fig. 5 is listener-in's bit error rate BER curve figure that simulating, verifying of the present invention obtains.
To keep the technical problem to be solved in the present invention, technical solution and main points clearer, below in conjunction with attached drawing and tool
Body embodiment is described in detail.
Specific embodiment
Refering to fig. 1.According to the present invention, wireless communication transmitting terminal compiles message bit sequence using LDPC encoder
Code, and code word is divided into message digit and check bit two parts, bit exclusive or fortune is carried out to the partial bit of the adjacent code word of transmitting terminal
It calculates, obtains new bit sequence；Sequence is handled by serioparallel exchange, using transmitting terminal BPSK modulator by newly-generated ratio
Check bit bit modulation that is special and having neither part nor lot in operation is BPSK symbol and is sent to receiving end；Receiving end is according to receiving
The priori log-likelihood ratio LLR value of BPSK symbol and preamble code word message digit, demodulates the log-likelihood ratio LLR of code word check bit
Value, and the log-likelihood ratio LLR value of the code word check bit is passed into receiving end ldpc decoder；Receiving end ldpc decoder will
The log-likelihood ratio LLR value of codeword message position is initialized as 0, and the posteriority of the codeword message position is calculated using belief propagation algorithm
Log-likelihood ratio LLR value, and the LLR value of the codeword message position is passed into receiving end BPSK demodulator；Receiving end BPSK demodulation
The codeword message position prior information and channel that device is fed back according to receiving end ldpc decoder receive symbol, verify to next code word
The log-likelihood ratio LLR value of position is demodulated, and is obtained the log-likelihood ratio LLR value of check bit and is passed to receiving end LDPC decoding
Device.Receiving end ldpc decoder and the mutual iteration interactive information of demodulator, such iteration goes on, until decoding out all codes
The message digit of word completes entire demodulation coding process.
Transmitting terminal includes system type LDPC encoder, serioparallel exchange module in sequential series, series processing module and BPSK demodulation
Device, receiving end include main awgn channel, receiving end BPSK demodulator and receiving end ldpc decoder, and listener-in includes eavesdropping AWGN
Channel, BPSK demodulator and listener-in's ldpc decoder.Transmitting terminal LDPC encoder utilizes system type LDPC encoder by length
It is encoded to the code word c that length is n for the message bit sequence b of k, is converted the codeword by serioparallel exchange module as check bit code cp
With message digit code cm.Series processing module handles sequence, the check bit code c that processing is generatedpWith bit sequence cnOutput
To BPSK demodulator.For i-th of code word ci, serioparallel exchange module be classified as length be k message digitThe check bit for being r=n-k with lengthTwo parts,
Wherein r >=k.In message digit bitIn, parameter i represents message digit bit and belongs to i-th of code word, and parameter m represents the bit
For message digit, it is t-th of bit that parameter t, which represents the bit, wherein 1≤t≤k.In check bit bitIn, parameter i is represented
Message digit bit belongs to i-th of code word, and parameter p represents the bit as check bit, and it is t-th of bit that parameter t, which represents the bit,
In 1≤t≤r.
Transmitting terminal carries out bit XOR operation, ρ > 1, for the 1st code word, transmitting terminal sequence to the partial bit of ρ original code word
Column processing module is by its check bitPass to BPSK modulator；For i-th of code wordWherein 1 < i≤ρ, transmitting terminal series processing module is by its preceding k bit check positionWith
The message digit of (i-1) a code wordBit XOR operation is carried out, length is obtained
For the neotectonics bit sequence of kThen, length is k's by transmitting terminal series processing moduleThe residue check position for being r-k with length
Pass to BPSK modulator；The ρ r bit modulation received is symbol sebolic addressing x by BPSK modulator, and with the shape of BPSK symbol
Formula is simultaneously transmitted to receiving end.Symbol sebolic addressing x divides two-way to arrive separately at receiving end and listener-in.
The BPSK symbol y that receiving end is received by main channel.Then, BPSK demodulator in receiving end is according to preamble code word message digit
Prior information and the BPSK symbol that receives, demodulate the LLR value L (c of current code word check bitp), and it is transmitted to receiving end
Ldpc decoder.Then, the LLR value of the codeword message position is initialized as 0 by receiving end ldpc decoder, and utilizes belief propagation
Algorithm obtains the log-likelihood ratio LLR value L (c of the codeword message positionm).The LLR value of message digit is converted to two by ldpc decoder
First bit sequenceEstimate the message sequence of transmitting terminal transmission.In addition, ldpc decoder is by the log-likelihood of codeword message position
Than LLR value L (cm) receiving end BPSK demodulator is passed to, as the prior information L for demodulating next code wordA(cm).BPSK demodulation
The codeword message position L that device is fed back according to receiving end ldpc decoderA(cm) prior information and channel receive symbol y, start to next
The log-likelihood ratio LLR value of a code word check bit is demodulated, such receiving end BPSK demodulator and receiving end ldpc decoder
Mutual iteration interactive information, the message digit until decoding out all code words complete entire demodulation coding process.
Listener-in obtains BPSK symbol z by the eavesdropping channel AWGN, and then, listener-in BPSK demodulator is according to preamble codeword message
The prior information of position and the BPSK symbol received, demodulate the LLR value L (c of current code word check bitp), and it is transmitted to eavesdropping
The LLR value of the codeword message position is initialized as 0 by person's ldpc decoder, then, listener-in's ldpc decoder, and is passed using confidence
It broadcasts algorithm and obtains the log-likelihood ratio LLR value L (c of the codeword message positionm).Listener-in's ldpc decoder is by the LLR value of message digit
Be converted to binary bits sequenceEstimate the message sequence of transmitting terminal transmission.In addition, ldpc decoder is by codeword message position
Log-likelihood ratio LLR value L (cm) listener-in's BPSK demodulator is passed to, as the prior information L for demodulating next code wordA
(cm).The codeword message position L that BPSK demodulator is fed back according to listener-in's ldpc decoderA(cm) prior information and channel receive symbol
Number y, starts to demodulate the log-likelihood ratio LLR value of next code word check bit, such listener-in BPSK demodulator and steals
The mutual iteration interactive information of hearer's ldpc decoder, the message digit until decoding out all code words complete entire demodulation coding mistake
Journey.
Below to the information process expansion narration in detail of receiving end.Since listener-in's information process and receiving end are handled
Process is completely the same, no longer carries out repeated description here.Receiving end BPSK demodulator receives biphase phase shift keying BPSK symbol
Sequences y=x+n, then, receiving end BPSK demodulator demodulate the check bit of code word, obtain its LLR value；Receiving end BPSK
The treatment process of demodulator is divided into two kinds of situations, the i.e. demodulation to the demodulation of the 1st code word to other ρ -1 code words, wherein
N be mean value be 0, variance σ2=N0/ 2 Gaussian sequence.
When the demodulation of the 1st code word, receiving end BPSK demodulator demodulates its check bit, to obtain its check bit
LLR value, for t-th of bit, LLR value isWherein, y is the BPSK symbol received, σ2For noise side
Difference.
When i-th of code word demodulation, receiving end BPSK demodulator demodulates its check bit, to obtain the LLR value of check bit.
It is k for length and carries out the check bit of bit XOR operation with preamble code word message digit, its t-th of (t≤k) bit is corresponding
LLR value be
Wherein, 1 < i≤ρ, 1≤t≤r, y are the BPSK symbol received, σ2For noise variance,It is that LDPC is translated
The prior information of t-th of message digit bit in (i-1) a code word of code device transmitting.It is the untreated of r-k for length
Check bit, its t-th of (k < t≤r) corresponding LLR value of bit beWherein, y is received
BPSK symbol, σ2For noise variance.Next, receiving end ldpc decoder decodes code word, codeword message position is obtained
LLR value simultaneously estimates message bit sequence, and treatment process is divided into two kinds of situations, i.e. the decoding to preceding ρ -1 code words and to ρ
The decoding of code word；When i-th of codeword decoding, wherein 1≤i < ρ, receiving end ldpc decoder receives the code word check bit's
LLR value sequenceBy the codeword message positionLLR value be initialized as 0, using setting
Letter propagation algorithm obtains the posteriority LLR value of message digitTo estimate transmitting terminal
The message bit of transmitting.For t-th of message bit, valuation is
Wherein, t≤k,For the LLR value after the bit decoding of t-th of codeword message position.Ldpc decoder is by i-th yard
The LLR value of word message digitBPSK demodulator is passed to, as BPSK demodulator meter
Calculate the prior information of (i+1) a code word check bit LLR value.For t-th of bit, i.e.,
When ρ codeword decoding, receiving end ldpc decoder receives the code word check bitLLR value sequence, i.e.,Receiving end ldpc decoder is by the codeword message positionLLR value be initialized as
0.Receiving end ldpc decoder obtains the posteriority LLR value of message digit using belief propagation algorithmTo estimate the message bit of transmitting terminal transmitting.For t-th of message ratio
Spy, t≤k, valuation are
Wherein,For the LLR value after the ρ t-th of codeword message position bit decoding.
Refering to Fig. 2.Transmitting terminal utilizes system type LDPC code, be length by the message bit sequential coding that length is k is n's
Code word.I-th of code word is divided into two parts by transmitting terminal, i.e. the length message digit that is kWith
Length is the check bit of r=n-kWherein r >=k.For message digit bitGinseng
Number i represents message digit bit and belongs to i-th of code word, and parameter m represents the bit as message digit, and it is t-th that parameter t, which represents the bit,
Bit.For check bit bitParameter i represents message digit bit and belongs to i-th of code word, and parameter p represents the bit as school
Position is tested, it is t-th of bit that parameter t, which represents the bit,.
For the 1st code wordTransmitting terminal is by its check bitIt is directly passed to modulator.For i-th yard
WordWherein 1 < i≤ρ, transmitting terminal is by its part check bitWith a upper code word's
Message digitBit XOR operation is carried out, new bit sequence is obtainedAnd pass to modulator.The code word is remaining not to join
With the check bit of bit XOR operationIt is also passed to modulator.
Receiving end ldpc decoder receives the check bit of i-th of code wordLLR value sequence, i.e.,Receiving end ldpc decoder is by the codeword message positionLLR value be initialized as
0.Receiving end ldpc decoder obtains the posteriority LLR value of message digit using belief propagation algorithmTo estimate the message bit of transmitting terminal transmitting.For t-th of message ratio
Spy, t≤k, valuation are
Wherein,For the LLR value after the bit decoding of t-th of codeword message position.
The foregoing is merely presently preferred embodiments of the present invention, is merely illustrative for the purpose of the present invention, and not restrictive
, those skilled in the art understand that it can be carried out in the spirit and scope defined by the claims in the present invention it is many change,
It modifies, is even equivalent, but falling in protection scope of the present invention.
Claims (10)
1. a kind of decoding method for wirelessly communicating physical layer communication safety, has following technical characteristic: wireless communication transmitting terminal
Message bit sequence is encoded using LDPC encoder, and code word is divided into message digit and check bit two parts, to transmission
It holds the partial bit of adjacent code word to carry out bit XOR operation, obtains new bit sequence；Sequence is carried out by serioparallel exchange
Processing by newly-generated bit and has neither part nor lot in the check bit bit modulation of operation using transmitting terminal BPSK modulator as BPSK symbol
And it is sent to receiving end；Receiving end is according to the BPSK symbol received and the priori log-likelihood ratio LLR of preamble code word message digit
Value, demodulates the log-likelihood ratio LLR value of code word check bit, and the log-likelihood ratio LLR value of the code word check bit is passed to
Receiving end ldpc decoder；The log-likelihood ratio LLR value of codeword message position is initialized as 0 by receiving end ldpc decoder, is utilized
Belief propagation algorithm calculates the posteriority log-likelihood ratio LLR value of the codeword message position, completes the decoding of the codeword message position.It connects
, the LLR value of the codeword message position is passed to receiving end BPSK demodulator by receiving end ldpc decoder；Receiving end BPSK demodulation
The codeword message position prior information and channel that device is fed back according to receiving end ldpc decoder receive symbol, verify to next code word
The log-likelihood ratio LLR value of position is demodulated, and is obtained the log-likelihood ratio LLR value of check bit and is passed to receiving end LDPC decoding
Device.Receiving end ldpc decoder and the mutual iteration interactive information of demodulator, such iteration goes on, until decoding out all codes
The message digit of word completes entire demodulation coding process.
2. the decoding method of wireless communication physical layer communication safety as described in claim 1, it is characterised in that: wireless communication
Transmitting terminal includes system type LDPC encoder, serioparallel exchange module in sequential series, series processing module and BPSK demodulator, nothing
Line communication receiver includes main awgn channel, receiving end BPSK demodulator and receiving end ldpc decoder, and listener-in includes eavesdropping
Awgn channel, BPSK demodulator and listener-in's ldpc decoder.It wirelessly communicates transmitting terminal LDPC encoder and utilizes system type LDPC
The message bit sequence b that length is k is encoded to the code word c that length is n by encoder, is converted the codeword by serioparallel exchange module
For check bit code cpWith message digit code cm, and export to BPSK demodulator；For i-th of code word ci, serioparallel exchange module is by its point
The message digit bit sequence for being k for lengthThe check bit bit sequence for being r=n-k with length
ColumnTwo parts, wherein r >=k.In message digit bitIn, parameter i represents message digit
Bit belongs to i-th of code word, and parameter m represents the bit as message digit, and it is t-th of bit that parameter t, which represents the bit, wherein 1≤t
≤k.In check bit bitIn, parameter i represents message digit bit and belongs to i-th of code word, and parameter p represents the bit as school
Position is tested, it is t-th of bit that parameter t, which represents the bit, wherein 1≤t≤r.
3. the decoding method of wireless communication physical layer communication safety as claimed in claim 2, it is characterised in that: transmitting terminal pair
The partial bit of ρ original code word carries out bit XOR operation, ρ > 1.For the 1st code word, transmitting terminal series processing module will
Its check bitPass to BPSK modulator；For i-th of code wordSend terminal sequence
Processing module is by its preceding k bit check positionWith the message digit of (i-1) a code wordBit XOR operation is carried out, the neotectonics bit sequence that length is k is obtainedWherein 1 < i≤ρ.Length is k's by transmitting terminal series processing moduleThe residue check position bit sequence for being r-k with lengthPass to BPSK modulator；The ρ r bit tune that BPSK modulator will receive
It is made as symbol sebolic addressing x, and in the form of BPSK symbol and is transmitted to receiving end, and symbol sebolic addressing x divides two-way to arrive separately to connect
Receiving end and listener-in.
4. the decoding method of wireless communication physical layer communication safety as described in claim 1, it is characterised in that: receiving end is logical
It crosses after main channel receives biphase phase shift keying BPSK symbol y, receiving end BPSK demodulator is according to the elder generation of preamble code word message digit
The biphase phase shift keying BPSK symbol testing information and receiving demodulates the LLR value L (c of current code word check bitp), and transmit
To receiving end ldpc decoder.The LLR value of codeword message position is initialized as 0 by receiving end ldpc decoder, utilizes belief propagation
Algorithm obtains the log-likelihood ratio LLR value L (c of the codeword message positionm), and the LLR value of message digit is converted into binary bits sequence
ColumnEstimate the message sequence of transmitting terminal transmission.Receiving end ldpc decoder is by the log-likelihood ratio LLR value of codeword message position
L(cm) receiving end BPSK demodulator is passed to, as the prior information L for demodulating next code wordA(cm)。
5. the decoding method of wireless communication physical layer communication safety as claimed in claim 4, it is characterised in that: BPSK demodulation
The codeword message position L that device is fed back according to receiving end ldpc decoderA(cm) prior information and channel receive symbol y, start to next
The log-likelihood ratio LLR value of a code word check bit is demodulated, such receiving end BPSK demodulator and receiving end ldpc decoder
Mutual iteration interactive information, the message digit until decoding out all code words complete entire demodulation coding process.
6. the decoding method of wireless communication physical layer communication safety as claimed in claim 4, it is characterised in that: receiving end
After BPSK demodulator receives biphase phase shift keying BPSK symbol sebolic addressing y=x+n, the check bit of code word is demodulated and obtained
Its LLR value, wherein n be mean value be 0, variance σ2=N0/ 2 Gaussian sequence.The processing of receiving end BPSK demodulator
Process is divided into two kinds of situations, the i.e. demodulation to the demodulation of the 1st code word to other ρ -1 code words；It is demodulated in the 1st code word
When, receiving end BPSK demodulator demodulates its check bit, and to obtain the LLR value of its check bit, t-th is compared
Spy, LLR value are
Wherein, 1≤t≤r, y are the biphase phase shift keying BPSK symbol received, σ2For noise variance.
7. the decoding method of wireless communication physical layer communication safety as claimed in claim 4, it is characterised in that: at i-th
When (1 < i≤ρ) code word demodulates, receiving end BPSK demodulator demodulates its check bit, to obtain the LLR value of check bit；
It is k for length and carries out the check bit of bit XOR operation with preamble code word message digit, its t-th of (t≤k) bit is corresponding
LLR value be
The untreated check bit for being r-k for length, its t-th of (k < t≤r) corresponding LLR value of bit are
Wherein, y is the BPSK symbol received, σ2For noise variance,It is (i-1) of ldpc decoder transmitting
The prior information of t-th of message digit bit in a code word.
8. the decoding method of wireless communication physical layer communication safety as claimed in claim 4, it is characterised in that: receiving end
Ldpc decoder decodes code word, obtains the LLR value of codeword message position and estimates message bit sequence, treatment process point
For the decoding to preceding ρ -1 code words and to two kinds of situations of decoding of the ρ code word, when i-th of (1≤i < ρ) codeword decoding, connect
Receiving end ldpc decoder receives the code word check bitLLR value sequenceIt should
Codeword message positionLLR value be initialized as 0, obtain the posteriority LLR value of message digit using belief propagation algorithmTo estimate the message bit of transmitting terminal transmitting；For t-th of message ratio
Spy, valuation areWherein, t≤k,It is translated for t-th of codeword message position bit
LLR value after code.
9. the decoding method of wireless communication physical layer communication safety as claimed in claim 4, it is characterised in that: receiving end
Ldpc decoder is by the LLR value of i-th of codeword message position (1≤i < ρ)Transmitting
BPSK demodulator is given, the prior information of (i+1) a code word check bit LLR value is calculated as BPSK demodulator；T-th is compared
It is special
10. the decoding method of wireless communication physical layer communication safety as claimed in claim 4, it is characterised in that: the ρ code
When transliteration code, receiving end ldpc decoder receives the code word check bitLLR value sequenceReceiving end ldpc decoder is by codeword message positionLLR value be initialized as 0,
The posteriority LLR value of message digit is obtained using belief propagation algorithmEstimate transmission
Hold the message bit of transmitting；For t-th of message bit, t≤k, valuation isWherein,For the LLR value after the ρ t-th of codeword message position bit decoding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910442318.8A CN110233701B (en) | 2019-05-25 | 2019-05-25 | Coding and decoding method for wireless communication physical layer communication safety |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910442318.8A CN110233701B (en) | 2019-05-25 | 2019-05-25 | Coding and decoding method for wireless communication physical layer communication safety |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110233701A true CN110233701A (en) | 2019-09-13 |
| CN110233701B CN110233701B (en) | 2021-11-19 |
Family
ID=67861055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910442318.8A Active CN110233701B (en) | 2019-05-25 | 2019-05-25 | Coding and decoding method for wireless communication physical layer communication safety |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110233701B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111342958A (en) * | 2020-02-13 | 2020-06-26 | 北京邮电大学 | Low-bit-error-rate Y-00 quantum noise stream encryption transmission method |
| CN111447160A (en) * | 2020-04-15 | 2020-07-24 | 上海交通大学 | Signal detection method of large-scale MIMO passive random access based on neural network |
| CN112003626A (en) * | 2020-08-31 | 2020-11-27 | 武汉梦芯科技有限公司 | LDPC decoding method, system and medium based on known bits of navigation message |
| CN113630163A (en) * | 2020-05-06 | 2021-11-09 | 哈尔滨工业大学 | Artificial noise assisted beam forming method with robustness for related stealing channels |
| CN114337925A (en) * | 2021-12-28 | 2022-04-12 | 福州大学 | Joint coding and decoding method based on polarization code and physical layer under non-orthogonal multiple access |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102064917A (en) * | 2011-01-11 | 2011-05-18 | 河海大学 | Demodulation decoding method for LDPC (Low Density Parity Code) modulation system |
| WO2015045897A1 (en) * | 2013-09-26 | 2015-04-02 | ソニー株式会社 | Data processing device and data processing method |
| CN104780022A (en) * | 2015-04-10 | 2015-07-15 | 清华大学 | Physical layer secure transmission method and system based on dynamic change of channel encoding matrix |
| WO2016079185A1 (en) * | 2014-11-19 | 2016-05-26 | Lantiq Beteiligungs-GmbH & Co.KG | Ldpc decoding with finite precision and dynamic adjustment of the number of iterations |
| CN106209710A (en) * | 2016-07-25 | 2016-12-07 | 河南科技大学 | A kind of method building first kind tapping channel under BI AWGN broadcast channel |
-
2019
- 2019-05-25 CN CN201910442318.8A patent/CN110233701B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102064917A (en) * | 2011-01-11 | 2011-05-18 | 河海大学 | Demodulation decoding method for LDPC (Low Density Parity Code) modulation system |
| WO2015045897A1 (en) * | 2013-09-26 | 2015-04-02 | ソニー株式会社 | Data processing device and data processing method |
| WO2016079185A1 (en) * | 2014-11-19 | 2016-05-26 | Lantiq Beteiligungs-GmbH & Co.KG | Ldpc decoding with finite precision and dynamic adjustment of the number of iterations |
| CN104780022A (en) * | 2015-04-10 | 2015-07-15 | 清华大学 | Physical layer secure transmission method and system based on dynamic change of channel encoding matrix |
| CN106209710A (en) * | 2016-07-25 | 2016-12-07 | 河南科技大学 | A kind of method building first kind tapping channel under BI AWGN broadcast channel |
Non-Patent Citations (2)
| Title |
|---|
| AHMADREZA AMIRZADEH 等: "Adaptive Granular HARQ LDPC-Based Coding for Secrecy Enhancement in Wiretap Channels", 《IEEE》 * |
| 白慧卿: "基于无线信道特征的物理层安全编码技术研究", 《中国优秀硕士学位论文全文数据库 信息科技辑》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111342958A (en) * | 2020-02-13 | 2020-06-26 | 北京邮电大学 | Low-bit-error-rate Y-00 quantum noise stream encryption transmission method |
| CN111447160A (en) * | 2020-04-15 | 2020-07-24 | 上海交通大学 | Signal detection method of large-scale MIMO passive random access based on neural network |
| CN113630163A (en) * | 2020-05-06 | 2021-11-09 | 哈尔滨工业大学 | Artificial noise assisted beam forming method with robustness for related stealing channels |
| CN112003626A (en) * | 2020-08-31 | 2020-11-27 | 武汉梦芯科技有限公司 | LDPC decoding method, system and medium based on known bits of navigation message |
| CN112003626B (en) * | 2020-08-31 | 2023-11-10 | 武汉梦芯科技有限公司 | LDPC decoding method, system and medium based on navigation message known bits |
| CN114337925A (en) * | 2021-12-28 | 2022-04-12 | 福州大学 | Joint coding and decoding method based on polarization code and physical layer under non-orthogonal multiple access |
| CN114337925B (en) * | 2021-12-28 | 2024-01-26 | 福州大学 | Combined coding and decoding method based on polarization code and physical layer under non-orthogonal multiple access |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110233701B (en) | 2021-11-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110233701A (en) | Wirelessly communicate the decoding method of physical layer communication safety | |
| US7415043B2 (en) | Code division multiple access (CDMA) method and apparatus for protecting and authenticating wirelessly transmitted digital information | |
| US20070121939A1 (en) | Watermarks for wireless communications | |
| US20050220322A1 (en) | Watermarks/signatures for wireless communications | |
| CN107148015B (en) | Continuous encryption physical layer secure transmission method based on polarization code structure | |
| CN104270227B (en) | Based on the empty safe transmission method of physical layer for moving keying in MISO system | |
| CN111065096B (en) | Physical layer encryption transmission system and method for wireless communication | |
| CN108632255A (en) | A kind of convert communication system based on random noise modulation | |
| CN104320777B (en) | A kind of method of the raising multiaerial system communication security based on beam forming | |
| CN107359929B (en) | Air interface encryption method based on constellation overlapping in bidirectional relay system | |
| CN101180846A (en) | Detection of signal modulation format type | |
| Borle et al. | Physical layer spectrum usage authentication in cognitive radio: Analysis and implementation | |
| CN101710852A (en) | LDPC code encoding/decoding method and encoder/decoder with encryption function | |
| Zhan et al. | A differential chaotic bit-interleaved coded modulation system over multipath Rayleigh channels | |
| CN109462456B (en) | Streaming media safe transmission method based on error code diffusion and noise aggregation | |
| CN109743155B (en) | Physical layer secure transmission method based on antenna selection differential chaos keying | |
| CN109617655A (en) | A kind of polarization code wireless data safe transmission method based on random scrambling code auxiliary | |
| CN109889254B (en) | Satellite-ground link physical layer secure communication method suitable for satellite communication | |
| CN109257743A (en) | The method that WTC-I is constructed by steady BSBC when no channel state information | |
| CN106059713A (en) | Method for constructing first-class wiretap channel through BSBC (Binary Symmetric Broadcast Channel) | |
| CN102647258B (en) | Cross-layer enhancing safety processing method of wireless communication MIMO (Multi-Input Multi-Output) system | |
| Vucetic et al. | Performance off 8-PSK trellis codes over nonlinear fading mobile satellite channels | |
| Vo-Huu et al. | Mitigating rate attacks through crypto-coded modulation | |
| CN106209710A (en) | A kind of method building first kind tapping channel under BI AWGN broadcast channel | |
| CN109688582A (en) | Without the method based on BI-AWGN channel build WTC-I under channel state information |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |