CN108540284B - Continuous variable quantum key distribution post-processing heterodyne detection phase compensation method - Google Patents
Continuous variable quantum key distribution post-processing heterodyne detection phase compensation method Download PDFInfo
- Publication number
- CN108540284B CN108540284B CN201810559087.4A CN201810559087A CN108540284B CN 108540284 B CN108540284 B CN 108540284B CN 201810559087 A CN201810559087 A CN 201810559087A CN 108540284 B CN108540284 B CN 108540284B
- Authority
- CN
- China
- Prior art keywords
- data
- phase
- phase compensation
- alice
- component
- 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.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
- H04L9/0852—Quantum cryptography
- H04L9/0858—Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Theoretical Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
- Optical Communication System (AREA)
Abstract
The invention discloses a continuous variable quantum key distribution post-processing heterodyne detection phase compensation method. The method comprises the following steps: 1) a receiving end Bob receives the quantum state prepared by the sender Alice and blocks data obtained by heterodyne detection according to a set proportion; 2) bob sends the phase compensation data to Alice; 3) calculating the phase drift of the X component and the phase drift of the P component of the two adjacent phase compensation data according to the two adjacent phase compensation data and the corresponding sending data recorded by the Alice during the quantum state preparation; 4) alice calculates the phase drift of the X component of the data to be compensated between the corresponding sending data recorded during the quantum state preparation according to the phase drift of the two adjacent phase compensation dataThe phase shift θ of the P component; 5) alice base onAnd theta performs phase rotation on X, P components of the data to be compensated to obtain the data after phase compensation.
Description
Technical Field
The invention relates to the technical field of quantum information, in particular to a data structure method for heterodyne detection phase compensation by post-processing in a continuous variable quantum key distribution system.
Background
Generally, after a signal is transmitted over a long distance, particularly when the signal is transmitted in an atmospheric channel, the phase of the signal light may shift to some extent due to the influence of the channel. For the receiver of the signal, it is necessary to perform phase compensation on the signal to obtain accurate information. In the continuous variable quantum key distribution protocol based on the optical fiber, a phase reference signal is generally added when a signal is sent, and a feedback voltage can be generated to a phase modulator on an intrinsic optical path of a receiving end by measuring the phase reference signal, so that real-time phase compensation is realized. In the atmospheric channel, the phase compensation is more complicated.
The phase compensation method using the electrical method is limited in accuracy of the electrical method by the accuracy of the digital and analog circuits, and the compensation accuracy is limited due to the extra electrical noise introduced during the compensation process.
Disclosure of Invention
In view of the technical problems in the prior art, an object of the present invention is to provide a method for performing phase compensation by post-processing in a continuous variable quantum key distribution protocol for heterodyne detection. The invention compensates the phase of the signal by using the algorithm in the post-processing of the signal, not only improves the precision of the phase compensation, but also reduces the complexity of a physical implementation system of a receiving end, greatly improves the flexibility and the portability of the phase compensation, and ensures that the phase compensation can be suitable for various external environments without making great data adjustment.
The method of the invention processes data, thereby avoiding the limitation brought by the problems, improving the precision of phase compensation and reducing the complexity of a physical realization system of a receiving end. In addition, the method has the advantages of flexible structure and strong portability because the proportion of the compensation data can be specifically adjusted according to the phase drift rate without changing the format of the whole data structure according to different experimental environments.
Aiming at the purposes, the technical scheme adopted by the invention is as follows:
a method for heterodyne detection phase compensation by post-processing is suitable for a continuous variable quantum key distribution system and comprises the following steps:
1) in a quantum key distribution system in which the data detected by the heterodyne are continuous variables, Bob selects data used for phase compensation according to a certain proportion from the data obtained by heterodyne detection, and the blocking proportion of the common data is that the phase compensation data and the data to be compensated are blocked in a ratio of 1: 9; the data after being partitioned are distributed at intervals according to the phase compensation data and the data to be compensated, and the phase drift of each block of data is constant; in addition, the phase compensation effect can also be optimized by selecting data with different proportions as phase compensation data according to different specific environment tests (the phase drift rate of the system needs to be determined according to specific experimental environments).
2) Bob sends the phase compensation data to Alice;
3) respectively calculating the phase drift of the phase compensation data of the X component (regular coordinate) data and the P component (regular momentum) data which are adjacent twice by Alice according to the phase compensation data and the data in the hand;
4) respectively calculating the phase drift of the data to be compensated between the adjacent X data and the data to be compensated between the adjacent P data by Alice according to the phase drift of the two adjacent phase compensation data;
5) and respectively carrying out phase rotation on the data X and the data P to be compensated according to the phase drift of the data to be compensated by Alice to obtain data after phase compensation.
Further, the data obtained by Bob through heterodyne detection in the step 1) comprises X component data XBAnd P component data PB。
Further, the data in the hand in step 3) refers to data information recorded by Alice during quantum state preparation, and includes X component (regular coordinate) data XAAnd P component (regular momentum) data PA。
Further, the method for calculating the phase drift of each phase compensation data in step 3) comprises the following steps:
3-1) Alice calculates the data X in the hand respectivelyAWith corresponding phase compensation data XBAnd PBTo obtain cov (X)A,XB) And cov (X)A,PB) (ii) a Data XAWith corresponding phase compensation data XBAnd PBIs data generated at the same time, in continuous variable quantum key distribution, if Bob uses heterodyne detection, Bob generates a set of data X each timeBAnd PBWill generate a set of X corresponding to AliceAAnd PA。
3-2) cov (X) obtained by the above calculationA,XB) And cov (X)A,PB) Calculating a phase drift of X component data of the phase compensation data
3-3) Alice calculates the data P in the hand respectivelyAAnd phase compensation data XBAnd PBTo obtain cov (P)A,XB) And cov (P)A,PB);
3-4) cov (P) obtained from the above calculationA,XB) And cov (P)A,PB) Calculating a phase drift θ of the P component data of the phase compensation data.
Further, cov (X) described in step 3-1)A,XB) And cov (X)A,PB) The calculation formula of (2) is as follows:
whereinThe phase drift of the X component data, which is phase compensation data, t represents a scaling factor, V, introduced during signal transmission due to noise and the likeAAnd the variance of modulation data at the Alice terminal is shown.
Further, the phase of the phase compensation data in step 3-2) is shiftedThe calculation formula of (2) is as follows:
cov therein(XA,PB) As data X in the handAAnd phase compensation data PBCovariance of (2), cov (X)A,XB) As data X in the handAAnd phase compensation data XBThe covariance of (a).
Further, cov (P) described in step 3-3)A,XB) And cov (P)A,PB) The calculation formula of (2) is as follows:
cov(PA,XB)=tVAsin(θ)
cov(PA,PB)=tVAcos(θ)
where θ is the phase shift of the P component data of the phase compensation data, t represents the scaling factor introduced by noise and the like during signal transmission, and VAThe variance of data sent by Alice side is shown.
Further, the calculation formula of the phase shift θ of the P component data of the phase compensation data in step 3-4) is:
cov (P) thereinA,XB) For compensating the data X for the phaseBAnd data P in handACovariance of (2), cov (P)A,PB) For compensating the data PBAnd data P in handAThe covariance of (a).
Further, if it is assumed that the data X phase drifts of the two adjacent phase compensation data in step 3) are respectivelyThe phase drift of the data to be compensated between the data sent corresponding to the two adjacent phase compensation data recorded by Alice during the quantum state preparation in the step 4) is
Further, if it is assumed that the two adjacent phase compensations in step 3) are performedThe data P of the data has a phase shift of theta1、θ2If so, the phase drift of the data to be compensated between the sending data corresponding to the two adjacent phase compensation data recorded by Alice during the quantum state preparation in the step 4) is theta0=0.5(θ1+θ2)。
Further, the data to be compensated X, P in step 5) is calculated as follows to perform phase rotation, so as to obtain data X 'and P' after phase compensation;
whereinFor the phase drift, theta, of the data to be compensated between the two adjacent X phase compensation data0And compensating the phase drift of the data to be compensated between the two adjacent data P phases.
The invention has the beneficial effects that:
the invention provides a method for heterodyne detection phase compensation by utilizing a post-processing mode, which is suitable for a continuous variable quantum key distribution system. The method reduces the complexity of a physical realization system of a receiving end by realizing phase compensation in the post-processing of a continuous variable quantum key distribution system; the flexibility and the portability of phase compensation are improved; meanwhile, as the method carries out phase compensation in a data processing mode, compared with the prior mode of passing through a circuit, the method improves the precision of phase compensation.
Drawings
FIG. 1 is a diagram illustrating the position relationship between phase compensation data and data to be compensated according to the present invention.
Fig. 2 is a flowchart of a method for performing heterodyne detection phase compensation by post-processing according to the present invention.
Detailed Description
In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.
In the continuous variable quantum key distribution system, Gaussian modulation data loaded on two regular components by Alice is assumed to be (X)A,PA) And transmitting the prepared quantum state to a receiving end Bob by Alice in a quantum channel. After receiving the quantum state, Bob detects the quantum state and obtains the received data, wherein heterodyne detection is one of the commonly used detection methods. In the heterodyne detection method, data detected by the Bob end is assumed to be XBAnd PBBecause the quantum state inevitably introduces noise and phase drift when passing through the quantum channel and two heterodyne detectors are needed for heterodyne detection, the receiving end is considered to be connected to the XBAnd PBRespectively, areAnd θ, then (X)A,PA) And XBOr PBThere is a relationship as shown in equation (1).
Wherein the content of the first and second substances,in order to shift the phase of data X, θ is the phase shift of data P, ξ and ξ' are noise, and t represents a scaling factor introduced during signal transmission due to noise and the like. In the invention, the sending end Alice needs to rotate the data X corresponding to the data in the hand by the phaseThe data P is rotated by the phase θ to counteract the phase drift. Since the speed of phase shift is a slow process to the data transmission rate, the phase shift of the data can be considered to be a constant value in a short time, so that the data can be divided into blocks, and phase compensation is performed separately for each block of data, and the phase shift in each block of data is considered to be constant. Referring to fig. 1, for data obtained by heterodyne detection, Bob selects a portion of the data in a certain proportion for phase compensation, called phase compensation data. And the rest of the data is reserved as the data to be compensated. Suppose Bob measures an X component ofMeasured P component ofDue to XA,PAξ are independent of one another, so that this part of the data corresponds to the corresponding partAndthe covariance was found to cov (X)A,XB) And cov (X)A,PB) As shown in equation (2).
And can calculate the phase compensation phase of the Alice terminalThe tangent of (c) is as shown in equation (3).
Covariance cov (P) may also be calculatedA,XB) And cov (P)A,PB) As shown in equation (4). And the tangent value of the phase θ of the phase compensation at the Alice end can be calculated as shown in equation (5).
cov(PA,XB)=tVAsin(θ)
cov(PA,PB)=tVAcos(θ) (4)
According to the above formulas (2) and (3) andandthe positive and negative relations of (2) can be calculated to calculate the phase drift of the data XThe phase shift θ of the data P can also be calculated. The phase drift calculation results of the phase compensation data of two adjacent data X are respectivelyThe phase drift calculation results of the phase compensation data of two adjacent data P are respectively theta1、θ2. For a linear circuit, the phase drift process can be understood according to simple linearity, and the phase drifts of the data to be compensated between the sending data corresponding to the two adjacent phase compensation data recorded when Alice performs quantum state preparation can be obtained asθ0=0.5(θ1+θ2)。
The present invention is explained below by referring to an embodiment, referring to fig. 2, the method steps of the embodiment include:
1) bob selects data used as phase compensation according to a certain proportion from data obtained by heterodyne detection, and uses the phase compensation data XB、PBAnd sending the data to Alice. For example, 500 out of every 5000 data are selected as phase compensation data.
2) Respectively calculating the phase compensation data X by AliceB、PBAnd hand data XAAnd data PACovariance of cov (X)A,XB)、cov(XA,PB)、cov(PA,XB)、cov(PA,PB). And according to covariance cov (X)A,XB) And cov (X)A,PB) And the above formula (3), using an inverse trigonometric function andandcalculating the phase drift of the phase compensation dataAccording to covariance cov (P)A,XB) And cov (P)A,PB) And the above equation (5), calculating the phase shift θ of the phase compensation data using the inverse trigonometric function and the positive-negative relationship of cos (θ) and sin (θ).
3) The phase drift calculation results of the two adjacent data X phase compensation data are respectivelyThe phase drift of the data to be compensated between the data sent corresponding to the two adjacent phase compensation data recorded by Alice during the quantum state preparation isThe phase drift calculation results of the phase compensation data of two adjacent data P are respectively theta1、θ2If so, the phase drift of the data to be compensated between the sending data corresponding to the two adjacent phase compensation data recorded by Alice during the quantum state preparation is θ equal to 0.5(θ ═ 0.5)1+θ2)。
4) And (3) performing calculation as shown in the following formulas (6) and (7) on the data to be compensated X, P between the sending data corresponding to the two adjacent phase compensation data recorded during quantum state preparation by Alice, performing phase rotation to obtain data X 'and P' after phase compensation, and storing the data X 'and P' as data of Alice for parameter estimation and subsequent post-processing.
The above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and a person skilled in the art can make modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the present invention, and the scope of the present invention should be determined by the claims.
Claims (10)
1. A continuous variable quantum key distribution post-processing heterodyne detection phase compensation method comprises the following steps:
1) a receiving end Bob receives the quantum state prepared by the sender Alice, detects the received quantum state through heterodyne detection, and then blocks data obtained through heterodyne detection according to a set proportion to obtain data of phase compensation data and data to be compensated which are distributed at intervals;
2) bob sends each phase compensation data to Alice; the phase compensation data comprises X component data and P component data;
3) according to the ith phase compensation data and corresponding sending data recorded by Alice during quantum state preparation, the Alice calculates the phase drift of the X component data in the ith phase compensation dataP component data phase drift θi(ii) a According to the i +1 th phase compensation data and corresponding sending data recorded by Alice during quantum state preparation, the Alice calculates the phase drift of the X component data in the i +1 th phase compensation dataP component data phase drift θi+1;
4) Alice compensates the phase drift of the X component data in the data according to the two adjacent phasesCalculating X component data X of data to be compensated between sending data corresponding to the two adjacent phase compensation data recorded when Alice carries out quantum state preparationDPhase drift ofAccording to the phase shift theta of P component data in two adjacent phase compensation datai、θi+1Calculating P component data P of data to be compensated between the data to be compensated and the data sent corresponding to the two adjacent phase compensation data recorded when the quantum state preparation is carried out by AliceDThe phase drift of θ;
2. The method of claim 1, wherein the quantum state is prepared by loading gaussian modulation data on two canonical components.
3. Method according to claim 1 or 2, characterized in that the phase drift is calculatedThe method comprises the following steps: alice calculates XAAnd XBCovariance of cov (X)A,XB)、XAAnd PBCovariance of cov (X)A,PB) Wherein X isBFor X component data, X, in the phase compensation data received by Bob at the ith timeAFor Alice to interact with X in the transmitted data recorded during quantum state preparationBCorresponding X component data, PBP component data in the phase compensation data received by Bob at the ith time; then according to cov (X)A,XB) And cov (X)A,PB) Calculating the phase drift
5. The method of claim 1 or 2, wherein the phase drift θ is calculatediThe method comprises the following steps: alice calculates PAAnd XBCovariance of cov (P)A,XB)、PAAnd PBCovariance of cov (P)A,PB) Wherein P isBCompensating for the phase received by Bob at the i-th timeData of P component in data, PAFor Alice to record the data in the sending data during the quantum state preparation and PBCorresponding P component data, XBThe data of the X component in the phase compensation data received by Bob at the ith time; then according to cov (P)A,XB) And cov (P)A,PB) Calculating the phase drift θi。
9. The method of claim 1, wherein the set ratio is 1:9, that is, the ratio of the phase compensation data to the data to be compensated in step 1) is 1: 9.
10. The method of claim 1, wherein Alice transmits the prepared quantum states in a quantum channel to a receiving end Bob.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201810559087.4A CN108540284B (en) | 2018-06-01 | 2018-06-01 | Continuous variable quantum key distribution post-processing heterodyne detection phase compensation method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201810559087.4A CN108540284B (en) | 2018-06-01 | 2018-06-01 | Continuous variable quantum key distribution post-processing heterodyne detection phase compensation method |
Publications (2)
Publication Number | Publication Date |
---|---|
CN108540284A CN108540284A (en) | 2018-09-14 |
CN108540284B true CN108540284B (en) | 2020-11-20 |
Family
ID=63473407
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201810559087.4A Active CN108540284B (en) | 2018-06-01 | 2018-06-01 | Continuous variable quantum key distribution post-processing heterodyne detection phase compensation method |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN108540284B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109889274B (en) * | 2019-03-25 | 2021-11-02 | 中南大学 | Novel continuous variable quantum key distribution system and phase estimation and compensation method thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102868520A (en) * | 2012-08-28 | 2013-01-09 | 上海交通大学 | Continuous variable quantum key distribution system and phase compensation method thereof |
EP2793425A1 (en) * | 2013-04-19 | 2014-10-22 | Sequrenet | Method and system for determining photon noise in optical communication devices |
CN105490805A (en) * | 2015-11-24 | 2016-04-13 | 上海斐讯数据通信技术有限公司 | System and method for reducing QKD (quantum key distribution) system bit error rate based on extended Kalman filter |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2011099589A1 (en) * | 2010-02-09 | 2011-08-18 | 日本電気株式会社 | Phase excursion/carrier wave frequency excursion compensation device and phase excursion/carrier wave frequency excursion compensation method |
CN103199994B (en) * | 2013-02-19 | 2016-03-02 | 华南师范大学 | The Active phase compensate method of Combisweep and device |
CN107135174B (en) * | 2016-02-29 | 2020-05-08 | 富士通株式会社 | Signal transmission device, carrier phase recovery device and method |
CN106092338A (en) * | 2016-06-16 | 2016-11-09 | 电子科技大学 | A kind of by the heterodyne detection method of time phase compensation Phase perturbation |
-
2018
- 2018-06-01 CN CN201810559087.4A patent/CN108540284B/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102868520A (en) * | 2012-08-28 | 2013-01-09 | 上海交通大学 | Continuous variable quantum key distribution system and phase compensation method thereof |
EP2793425A1 (en) * | 2013-04-19 | 2014-10-22 | Sequrenet | Method and system for determining photon noise in optical communication devices |
CN105490805A (en) * | 2015-11-24 | 2016-04-13 | 上海斐讯数据通信技术有限公司 | System and method for reducing QKD (quantum key distribution) system bit error rate based on extended Kalman filter |
Non-Patent Citations (2)
Title |
---|
《Generating the Local Oscillator "Locally" in Continuous-Variable Quantum Key Distribution Based on Coherent Detection》;Bing Qi et al.;《PHYSICAL REVIEW X》;20151021;第5卷(第4期);全文 * |
《连续变量量子密钥分发实验系统及安全性研究》;韩二虎;《中国优秀硕士学位论文全文数据库 信息科技辑》;20151215;全文 * |
Also Published As
Publication number | Publication date |
---|---|
CN108540284A (en) | 2018-09-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP2008526152A (en) | Transmitter | |
CN108881085B (en) | Method and system for estimating carrier frequency offset | |
EP1444815A1 (en) | Data-aided frequency offset detection using phase unwrapping | |
CN108540284B (en) | Continuous variable quantum key distribution post-processing heterodyne detection phase compensation method | |
CN105227500A (en) | A kind of compensation method of phase deviation and device | |
TW201038028A (en) | Carrier recovery device and related method | |
US6111921A (en) | Estimator of error rate | |
CN113466670A (en) | Time delay measuring circuit, AC calibration device and IC measuring device | |
CN108540285B (en) | Continuous variable quantum key distribution post-processing homodyne detection phase compensation method | |
CN105680858B (en) | A method of estimation TIADC parallel acquisition system time offset errors | |
JP2008211760A (en) | Modulation system estimation apparatus | |
US20050041725A1 (en) | Receiver of an ultra wide band signal and associated reception method | |
CN106878213A (en) | A kind of method that LTE uplink frequency offsets are estimated | |
CN116346558B (en) | Method and system for generating orthogonal signals | |
CN107276694B (en) | Error vector magnitude measuring device and method | |
US11349523B2 (en) | Spread-spectrum modulated clock signal | |
US11435455B2 (en) | Multi-phase correlation vector synthesis ranging method and apparatus | |
US11899097B2 (en) | Distance measurement device and distance measurement method | |
CN108353066B (en) | Apparatus and method for carrier frequency offset correction and storage medium thereof | |
CN113644934B (en) | Satellite-ground heterogeneous spread spectrum frequency hopping carrier capturing frequency compensation method and system | |
CN115242367B (en) | Data error correction method for industrial wireless channel impulse response | |
JP3568284B2 (en) | Demodulation method and demodulation device | |
Colonnese et al. | Gain-control-free blind carrier frequency offset acquisition for QAM constellations | |
KR20030003230A (en) | Correction of quadrature and gain errors in homodyne receives | |
CN109510661B (en) | Method and device for measuring IQ delay difference in optical transmitter and optical transmitter |
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 |