CN103095440A - System and method for hybrid automatic request retransmission in free space optical communication - Google Patents
System and method for hybrid automatic request retransmission in free space optical communication Download PDFInfo
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Abstract
The invention discloses a system and a method for hybrid automatic request retransmission in free space optical communication, and mainly solves the problem of reliability in an existing free space optical communication. In the system and the method for the hybrid automatic request retransmission in the free space optical communication, a blocking, error detecting and coding module achieves self-adaption blocking and error detection coding for sent data under the control of a self-adaption control module. An error correction coding module achieves error correction coding for error detection coded data. A diversity sending and controlling module achieves diversity sending for error correction coded data under the control of the self-adaption control module. A diversity receiving module achieves diversity receiving for received data. A code merging and error correction coding module achieves self-adaption code merging and error correction coding for diversity received data under the control of the self-adaption control module. The blocking, error detecting and coding module achieves block coding for the error correction coded data and requires retransmission. The system and the method for the hybrid automatic request retransmission in the free space optical communication improve reliability of a communication system, give consideration to communication instantaneity and transmission efficiency, and can be used in the field of the free space optical communication.
Description
Technical field
The invention belongs to communication technical field, further relate to a kind of free space optical communication (the Free Space Optical in the error-control technique field of free space optical communication, FSO) mix automatic repeat request (Hybrid Automatic Repeat reQuest, HARQ) system and method in.In the free-space optical communication system that the present invention can be used for real-time, reliability and efficiency of transmission are had higher requirements.
Background technology
Free space optical communication is a kind of Wideband wireless communication technology that communicates as carrier take light (mainly referring to laser) in free space.It has that modulation rate is high, bandwidth, capacity greatly, do not take frequency spectrum resource, good confidentiality, cost is low, installation is quick, protocol transparent and the plurality of advantages such as networking flexibility is convenient, be one of best mode of the following wide-band mobile communication of generally acknowledging, thereby have broad application prospects.In recent years, along with substantially building up of backbone network, the appearance of last kilometer problem, the development of each side technology, the maturation gradually of equipment development, and broadband data service and the driving of emergency traffic fast, FSO has been subject to people's extensive attention as one of Communication Highlights technology.
FSO is subjected to the impact of weather conditions, orographic condition, exotic larger, particularly the random error and burst error that causes of time change, multipath, shade, the Doppler frequency shift etc. in atmospheric channel can the severe exacerbation systematic function, affects FSO Systems balanth and reliability.Simultaneously, growing broadband data service and quick emergency traffic are also had higher requirement to real-time and the reliability of system.The method that in FSO, tradition improves communication quality mainly contain large aperture reception technique, multiple beam transmission diversity technique, multi-wavelength transmission technology, partially coherent optical transport technology, catch, aim at and follow the tracks of (Acquisition Pointing and Tracking, APT) technology, adaptive optical technique and modulation-demodulation technique etc.But these technical methods have certain limitation, they are often only effective when condition is better, when weather conditions during abominable and other worsening conditions, it is even invalid that these method performances sharply descend, and in various degree have that range of application is little, complexity is high, bandwidth availability ratio is low, the time shortcoming such as prolongation.
Therefore, improving the reliability and stability of communicating by letter is one of key technology of FSO.HARQ combines automatic repeat request (Automatic Repeat reQuest as a kind of error-control technique, ARQ) high reliability and forward error correction (Forward Error Correction, FEC) high-efficiency, stability and the reliability of the more effective assurance of the energy FSO communication under mal-condition of relatively traditional method, thereby be subject to people's attention, but the research that applies it in the FSO system also is in the starting stage.
At present HARQ mode commonly used mainly contains three kinds: I type HARQ all retransmits information sequence and verification sequence thereof and carries out code merging, II type HARQ alternately retransmits information sequence and verification sequence and merges decoding with the information sequence that has sent or verification sequence, III type HARQ with information sequence and verification sequence according to the punching matrix partial retransmission.These 3 kinds of HARQ modes exist some shortcomings, such as, in the burst error situation, all mistakes concentrate on the sub-fraction of data usually, even only there is the mistake of a small amount of bit after decoding, whole data still need retransmit, and cause system effectiveness significantly to reduce; Repeatedly re-transmission makes data transmission delay long, can't guarantee real-time reception; The memory capacity of sending and receiving end storage data retransmission is large, consumes resources; Receive data can't fully merge, and easily loses effective reception information etc.In existing HARQ system, generally take following methods to improve systematic function.
The people such as Zhou Qinying are at " based on the New HARQ System of block data transmission " (" Xian Electronics Science and Technology University's journal " natural science edition 200532 (5): propose a kind of novel HARQ method based on the block data transmission 720-723).This method is determined block count and the required number of retransmissions of correct transmission of every frame data according to the channel situation of estimating, Frame is carried out piecemeal and according to the number of retransmissions of estimating, each piecemeal copied, then each piecemeal is carried out CRC check, merge at last a Frame and send.This method can reduce delay of feedback, improves the real-time of system.But the weak point that the method exists is, because each piecemeal to Frame copies and CRC check, makes data volume large, produces too much redundant information; Send together after the identical piecemeal that copies merges, can increase the correlation of minute interblock, make receive data fully to merge, be unfavorable for improving code and merge performance; And after decoding, correct piecemeal receives, and the piecemeal of mistake abandons, and does not retransmit, and can destroy the integrality of transmitting data frame.
Proposing a kind of parallel redundancy in the patent of Southwest Jiaotong University's application " parallel redundancy sends and the parallel method that receives grouped data that merges in the mixed automatic retransmission Request System " (publication number CN1444352A application number 02133719.5, applying date 2002.9.9) sends and the parallel method that receives grouped data that merges.The transmitting terminal of the method will carry out packet after error correction coding through the perforation of N puncture module processing after, then the time line number order be the parallel transmission of N; Receiving terminal to parallel receive to packet recover through N depuncture module, then carry out code merging processing.The weak point that the method exists is, be applied in cdma system, the parallel number N that sends equals the orthogonal channel number of codes that the CDMA packet data communication system distributes, and is fixed value, can not carry out adaptive adjustment with the channel situation, be unfavorable for the raising of efficiency of transmission; For after error-correcting decoding still vicious grouping abandon and request retransmission, retransmit the parallel redundancy transmission and the parallel redundancy that still re-execute whole grouped data and merge reception, even mistake only concentrates on a bit of of grouping like this, whole data still need retransmit, and cause the reduction of efficiency of transmission.
Summary of the invention
The object of the invention is to overcome above-mentioned the deficiencies in the prior art, a kind of mixed automatic retransfer system for free space optical communication and method are provided, to satisfy free space optical communication to the requirement of real-time, reliability and efficiency of transmission.
For achieving the above object, thinking of the present invention is: self adaptation piecemeal transmission technology, adaptive diversity technology and adaptive code folding are applied in mixed automatic retransfer system, can be according to current channel condition, dynamically adjust the block count of Frame, the diversity number of send and receive, coding mode and the code merging method of each diversity, thereby improved the reliability of free-space optical communication system, and taken into account real-time and efficiency of transmission.
System of the present invention comprises transmitting portion, receiving unit and control section, wherein:
Transmitting portion comprises piecemeal error detection coding module, error correction coding module, diversity transmission module; The output of piecemeal error detection coding module connects the input of error correction coding module, and the output of error correction coding module connects the input of diversity transmission module; Piecemeal error detection coding module is used under self-adaptive control module is controlled, and carries out the error detection coding of self adaptation piecemeal and piecemeal to sending Frame, and retransmits when piecemeal is made mistakes; The error correction coding module is used for the Frame of piecemeal error detection coding module output is carried out error correction coding; The diversity transmission module is used for the Frame after error correction coding being carried out adaptive diversity sending under self-adaptive control module is controlled.
Receiving unit comprises that diversity reception module, code merge and error-correcting decoding module, piecemeal error detection decoding module; The output of diversity reception module connects the input of code merging and error-correcting decoding module, and code merges and is connected the input of piecemeal error detection decoding module with the output of error-correcting decoding module; The diversity reception module is used for the Frame that receives is carried out diversity reception and decoding; Code merges and the error-correcting decoding module, is used under self-adaptive control module is controlled, the diversity reception data being carried out code and merges and error-correcting decoding; Piecemeal error detection decoding module is used for the Frame after error-correcting decoding is carried out piecemeal error detection decoding, and provides corresponding feedback information.
Control section comprises signal-to-noise ratio (SNR) estimation module, self-adaptive control module; The output of signal-to-noise ratio (SNR) estimation module connects the input of self-adaptive control module, and the output of self-adaptive control module merges and is connected with the input of error-correcting decoding module with input, the input of diversity transmission module, the code of piecemeal error detection coding module respectively; The signal-to-noise ratio (SNR) estimation module is used for the signal to noise ratio of current channel is estimated; Self-adaptive control module, be used for the required number of retransmissions of transmission correct in feedback information, signal-to-noise ratio (SNR) estimation information and previous frame data and estimate current channel condition, and produce control information according to the current channel condition of estimating, realize to diversity number and coding mode, code in the block count that sends Frame in piecemeal error detection coding module, diversity transmission module merge with the error-correcting decoding module in code merge the adaptive control of mode.
Method of the present invention comprises two steps in process of transmitting and receiving course, wherein:
The concrete steps of process of transmitting comprise as follows:
(1) generate a plurality of deblockings:
The Data Division module receives the control information of self-adaptive control module, carries out the self adaptation piecemeal according to the piecemeal control information in control information to sending Frame, generates corresponding a plurality of deblockings.
(2) generate a plurality of error detection coding piecemeals:
2a) a plurality of error detection coding unit carries out error detection coding to a plurality of deblockings, and for each piecemeal distributes corresponding piecemeal number, generates a plurality of error detection coding piecemeals.
2b) divide block cache to merge module a plurality of error detection coding piecemeals are carried out buffer memory.
(3) merge re-transmission:
3a) divide block cache to merge the control information that module receives self-adaptive control module.
3b) divide block cache to merge whether to exist in the control information that the module judgement receives the piecemeal number that retransmits piecemeal, if exist, will retransmit with number corresponding piecemeal of makeing mistakes of piecemeal; If there is no, divide block cache to merge module with step 2b) in a plurality of error detection coding piecemeals of buffer memory be merged into a Frame, and this Frame is sent to the error correction coding module.
(4) error correction coding:
The error correction coding module is carried out error correction coding to the Frame that receives, and generates corresponding error correction encoded data.
(5) adaptive diversity sends:
5a) the diversity transmission control module receives the diversity control information of self-adaptive control module.
5b) the diversity transmission control module is under the control of diversity control information, adopt adaptive approach selection diversity number and the mixing automatic repeat request type that is respectively I, II, III, select coding mode according to selected mixing automatic repeat request type for each diversity, coding mode is consistent with selected mixing automatic repeat request type.
5c) the diversity transmission control module is encoded to error correction encoded data according to selected coding mode, generates corresponding diversity coded data.
5d) transmitting element carries out diversity transmission to the diversity coded data on respective diversity.
The concrete steps of receiving course comprise as follows:
(6) diversity reception decoding:
6a) receiving element detects receive data, when the diversity coded data being detected, it is carried out diversity reception.
6b) diversity translated code cache module to each diversity reception to the diversity coded data carry out decoding, generate corresponding diversity decoding data.
6c) diversity translated code cache module is carried out buffer memory to the diversity decoding data.
(7) code merges:
Code merges the control information that receives self-adaptive control module with the error-correcting decoding module, and merges a control information according to the code in control information and the diversity decoding data is carried out code merge and process, and generates corresponding yard merging data.
(8) error-correcting decoding:
Code merges and the error-correcting decoding module is carried out error-correcting decoding to the code merging data, generates corresponding error-correcting decoding data.
(9) piecemeal error detection decoding:
9a) the Data Division module is carried out piecemeal to the error-correcting decoding data, generates corresponding a plurality of deblockings.
9b) the error detection decoding unit carries out error detection decoding to a plurality of deblockings, generates a plurality of error detection decoding piecemeals that comprise right and wrong.
9c) divide block cache to merge module to carrying out buffer memory through the piecemeal after error detection coding, the error detection decoding piecemeal of request retransmission mistake, and record piecemeal number and the number of retransmissions of correct error detection decoding piecemeal, when all piecemeals all correctly receive or after number of retransmissions reaches the maximum of default, each piecemeal are merged into a Frame submit to.
The present invention compared with prior art has the following advantages:
The first, the present invention has adopted structure and the self adaptation block transmission method that transmits based on the self adaptation piecemeal due to system, realized the coupling of block count and the current channel condition of Frame, and only retransmit the piecemeal of makeing mistakes, overcome in the prior art and transmitted and efficiency of transmission low shortcoming poor to channel adaptability without piecemeal or fixed block, made the present invention improve efficiency of transmission and the real-time of system.
The second, the present invention is because system has adopted structure and adaptive diversity method based on adaptive diversity, the several dynamic adjustment according to current channel condition of diversity have been realized, overcome a plurality of identical data piecemeals serial simultaneously transmission in prior art, the correlation of minute interblock is increased, thereby the shortcoming that receive data can't fully merge, make the present invention can reduce correlation between Frame, improve the performance that code merges, thereby increase the reliability of error-correcting decoding, reduce number of retransmissions, reduce the time delay of system; Simultaneously, also overcome the fixing minute poor shortcoming of set pair channel adaptability in the prior art, made the present invention can improve the efficiency of transmission of system.
the 3rd, the present invention is owing to each diversity being adopted the method for adaptive coding, and adjust the coding mode of each diversity by residual matrix, realized that selected HARQ type is according to the dynamic adjustment of current channel condition, only use by the form of dynamic adjustment residual matrix and realize dynamic adjustment to coding mode, thereby can avoid configuring simultaneously the independently HARQ of three types in system, make the present invention can effectively take into account system transmissions efficient and reliability, reduce system complexity, the consumption of minimizing to hardware resource, reach the unified effect of systematic function and implementation complexity.
Four, the present invention is owing to adopting adaptive code merging method, realized the coupling of the HARQ type of code merging mode and current channel condition and employing, overcome and used the single code merging method shortcoming poor to channel adaptability in the prior art, the code that makes the present invention can improve system merges performance, increases reliability of decode.
Five, the present invention is when carrying out code merging processing to data retransmission, the Frame that retransmits merges with the Frame through after error-correcting decoding of last transmission, overcome that in the prior art, code merges the shortcoming that can not take full advantage of the effective information that increases in the error-correcting decoding process, the code that makes the present invention can improve system merges performance, increase reliability of decode, and then the minimizing number of retransmissions, reduce the time delay of system.
Description of drawings
Fig. 1 is system block diagram of the present invention;
Fig. 2 is transmitting portion structural representation in system of the present invention;
Fig. 3 is receiving unit structural representation in system of the present invention;
Fig. 4 is process of transmitting flow chart in method of the present invention;
Fig. 5 is receiving course flow chart in method of the present invention.
Embodiment
The present invention is described in further detail below in conjunction with accompanying drawing.
With reference to accompanying drawing 1, system of the present invention comprises transmitting portion, receiving unit and control section.
Transmitting portion comprises piecemeal error detection coding module, error correction coding module, diversity transmission module.
The output of piecemeal error detection coding module connects the input of error correction coding module, and the output of error correction coding module connects the input of diversity transmission module.Piecemeal error detection coding module is used under self-adaptive control module is controlled, and carries out the error detection coding of self adaptation piecemeal and piecemeal to sending data, and retransmits when piecemeal is made mistakes.The error correction coding module is used for the Frame of piecemeal error detection coding module output is carried out error correction coding.The diversity transmission module is used for the Frame after error correction coding being carried out adaptive diversity sending under self-adaptive control module is controlled.
Piecemeal error detection coding module in transmitting portion comprises that Data Division module, M (M for greater than 1 integer) individual error detection coding unit and minute block cache merge a module, described the structural relation between piecemeal error detection coding module included Data Division module, a M error detection coding unit and minute block cache merging module in accompanying drawing 2.The M of a Data Division module output is connected with the input of M error detection coding unit respectively, the output of M error detection coding unit is connected with M the input that minute block cache merges module respectively, divide the input of the output connection error correction coding module of block cache merging module, the output of self-adaptive control module is connected with the input that minute block cache merges module with the input of Data Division module respectively.
The Data Division module is used under self-adaptive control module is controlled, and carries out the self adaptation piecemeal to sending Frame, and piecemeal is sent to the error detection coding unit.
M error detection coding unit is used for each piecemeal is carried out error detection coding, and the piecemeal after error detection coding is sent to a minute block cache merging module.M is the integer greater than 1, and its maximum determined by the applied environment of system and partition strategy, and the number of using in reality sends data with each, and to pass through the actual block count that Data Division module carries out after piecemeal identical.
Minute block cache merges module, be used for carrying out buffer memory and merging through the piecemeal after error detection coding, and the Frame after merging sends to the error correction coding module, and under the control of self-adaptive control module, the piecemeal of makeing mistakes is retransmitted.
Diversity transmission module in transmitting portion comprises the individual transmitting element of diversity transmission control module and N (N for greater than 1 integer), described the structural relation between the included diversity transmission control module of diversity transmission module and N transmitting element in accompanying drawing 2.The output of error correction coding module connects the input of diversity transmission control module, and the N of a diversity transmission control module output is connected with the input of N transmitting element respectively, and the output of self-adaptive control module connects the input of diversity transmission control module.
The diversity transmission control module is used for carrying out adaptively selected according to the control information of self-adaptive control module to the diversity number of data transmission and the coding mode of each diversity.
N transmitting element is used for the Frame of each diversity is sent.N is the integer greater than 1, and its maximum is definite by applied environment and the diversity strategy of system, and the number of using in reality is identical with the selected diversity number of diversity transmission control module.
Receiving unit comprises that diversity reception module, code merge and error-correcting decoding module, piecemeal error detection decoding module.
The output of diversity reception module connects the input of code merging and error-correcting decoding module, and code merges and is connected the input of piecemeal error detection decoding module with the output of error-correcting decoding module.The diversity reception module is used for the Frame that receives is carried out diversity reception and decoding.Code merges and the error-correcting decoding module, is used under self-adaptive control module is controlled, the diversity reception data being carried out code and merges and error-correcting decoding.Piecemeal error detection decoding module is used for the Frame after error-correcting decoding is carried out piecemeal error detection decoding, and provides corresponding feedback information.
Diversity reception module in receiving unit comprises N (N for greater than 1 integer) individual receiving element and diversity translated code cache module, in accompanying drawing 3, included N the receiving element of diversity reception module and the structural relation between diversity translated code cache module is illustrated.The output of N receiving element is connected with N input of diversity translated code cache module respectively, and the output of diversity translated code cache module connects the input of code merging and error-correcting decoding module.
N receiving element is used for the Frame of each diversity is received, and N is the integer greater than 1, and its maximum is identical with the maximum of transmitting element number in the diversity transmission module, and the number of using in reality is identical with actual transmission diversity number.
Diversity translated code cache module is used for the Frame of each diversity reception is carried out decoding and buffer memory, and the Frame after decoding is sent to code merging and error-correcting decoding module.
Piecemeal error detection decoding module in receiving unit comprises that Data Division module, M (M is the integer greater than 1) individual error detection decoding unit and minute block cache merge a module.Described included Data Division module, the M error detection decoding unit of piecemeal error detection decoding module and reached the structural relation of dividing between block cache merging module in accompanying drawing 3.Code merges the input that splits module with the output connection data of error-correcting decoding module, the M of a Data Division module output is connected with the input of M error detection decoding unit respectively, and the output of M error detection decoding unit is connected with a minute M input of block cache merging module respectively.
The Data Division module is used for the receiving data frames after error correction coding is carried out piecemeal, and piecemeal is sent to the error detection decoding unit.
M error detection decoding unit, be used for each piecemeal is carried out error detection coding, and the piecemeal after error detection coding is sent to a minute block cache merging module, M is the integer greater than 1, identical in its maximum and piecemeal error detection coding module, the actual block count that the number of using in reality and each receive data carry out after piecemeal through Data Division module is identical.
Divide block cache to merge module, be used for carrying out buffer memory through the piecemeal after error detection coding, the error detection decoding piecemeal of request retransmission mistake is when all piecemeals all correctly receive or after number of retransmissions reaches the maximum of default, each piecemeal are merged into a Frame submit to.
Control section comprises signal-to-noise ratio (SNR) estimation module, self-adaptive control module.
The output of signal-to-noise ratio (SNR) estimation module connects the input of self-adaptive control module, and the output of self-adaptive control module merges and is connected with the input of error-correcting decoding module with input, the input of diversity transmission module, the code of piecemeal error detection coding module respectively.The signal-to-noise ratio (SNR) estimation module is used for the signal to noise ratio of current channel is estimated; Self-adaptive control module, be used for according to the required number of retransmissions of the correct transmission of feedback information, signal-to-noise ratio (SNR) estimation information and previous frame data, current channel condition being estimated, and produce control information according to the current channel condition of estimating, realize to diversity number and coding mode, code in the block count that sends Frame in piecemeal error detection coding module, diversity transmission module merge with the error-correcting decoding module in code merge the adaptive control of mode.
Method of the present invention comprises process of transmitting and receiving course.
With reference to accompanying drawing 4, process of transmitting in method of the present invention is described further.
Step 1 generates a plurality of deblockings.
The signal-to-noise ratio (SNR) estimation module is estimated the signal to noise ratio of current channel, and signal-to-noise ratio (SNR) estimation information is sent to self-adaptive control module, if do not carry out the transmission of data, self-adaptive control module is estimated current channel condition according to signal-to-noise ratio (SNR) estimation information; If carried out the transmission of data, the comprehensive signal-to-noise ratio (SNR) estimation information of self-adaptive control module, feedback information, the required information such as number of retransmissions of the correct transmission of previous frame data are estimated current channel condition.Self-adaptive control module carries out the self adaptation piecemeal according to the current channel condition of estimating to sending Frame: if current channel condition is good, reduce block count, if current bad channel conditions increases block count.The piecemeal number that increases or reduce is consistent with the change trend of current channel condition, self-adaptive control module is compared the current channel condition of estimating with the last channel condition of estimating, if it is large that current channel condition changes degree, the piecemeal number that increases or reduce is just many, if it is little that current channel condition changes degree, the piecemeal number that increases or reduce is just few.Self-adaptive control module is put into the piecemeal control information with block count and is sent to the Data Division module, the Data Division module is carried out the self adaptation piecemeal according to the block count in the piecemeal control information to sending data, and a plurality of deblockings that generate are sent in M error detection coding unit unit accordingly.If the deblocking number is less than M, the unit number of using in reality is identical with block count.
Step 2 generates a plurality of error detection coding piecemeals.
M error detection coding unit carries out error detection coding to the deblocking that receives, and for each piecemeal distributes corresponding piecemeal number, generates corresponding a plurality of error detection coding piecemeal, and send to the error detection coding piecemeal a minute block cache merging module to carry out buffer memory.
Step 3 merges re-transmission.
Self-adaptive control module judges whether that according to feedback information the piecemeal needs of makeing mistakes retransmit, if having, needs the piecemeal of the piecemeal that retransmits number to put into Retransmission control information and send to the piecemeal buffer memory to merge module; If no, do not put into any piecemeal number in Retransmission control information.Minute block cache merges module and judges whether the piecemeal that exists needs to retransmit according to Retransmission control information, if exist, number retransmits corresponding piecemeal according to the piecemeal in Retransmission control information; If there is no, the piecemeal with buffer memory in step 2 is merged into a Frame, and this Frame is sent to the error correction coding module.
(4) error correction coding.
The error correction coding module is carried out error correction coding to the Frame that receives, and generates corresponding error correction encoded data, and error correction encoded data is sent to the diversity transmission module.
(5) adaptive diversity sends.
The signal-to-noise ratio (SNR) estimation module is estimated the signal to noise ratio of current channel, and signal-to-noise ratio (SNR) estimation information is sent to self-adaptive control module, if do not carry out the transmission of data, self-adaptive control module is estimated current channel condition according to signal-to-noise ratio (SNR) estimation information; If carried out the transmission of data, the comprehensive signal-to-noise ratio (SNR) estimation information of self-adaptive control module, feedback information, previous frame data are correctly transmitted the required current channel condition of the information estimators such as number of retransmissions.
Self-adaptive control module is according to the current channel condition of estimating, adaptively selected diversity number and mixing automatic repeat request HARQ type, and selected diversity number and HARQ type are put into the diversity control information send to the diversity transmission control module, the diversity transmission control module is carried out the selection of diversity number and HARQ type according to the diversity number in the diversity control information and HARQ type, and selects corresponding coding mode according to selected HARQ type for each diversity.
Self-adaptive control module is estimated the required number of retransmissions of current correct transmission one Frame according to the current channel condition of estimating, determine the diversity number by the number of retransmissions of estimating: if current channel condition is good, required number of retransmissions is few, corresponding minimizing diversity number, if current bad channel conditions, required number of retransmissions is many, corresponding increase diversity number.
Self-adaptive control module selects to mix automatic repeat request HARQ type according to the current channel condition of estimating: if current channel condition is good, and Selective type I mixing automatic repeat request HARQ; If current channel condition is medium, Selective type II mixing automatic repeat request HARQ; If current bad channel conditions, Selective type III mixing automatic repeat request HARQ.
Self-adaptive control module is put into the diversity control information with selected diversity number and HARQ type and is sent to the diversity transmission control module, the diversity transmission control module is carried out the selection of diversity number and HARQ type according to the diversity number in the diversity control information and HARQ type, and selects corresponding coding mode according to selected HARQ type for each diversity.Coding mode is by selecting corresponding residual matrix to realize: when adopting type i to mix automatic repeat request HARQ, use the residual matrix of regular coding; When adopting Type II or type-iii mixing automatic repeat request HARQ, use the residual matrix of rate-matched.
The diversity transmission control module is encoded to error correction encoded data according to selected coding mode, generates corresponding diversity coded data, and the diversity coded data is sent to corresponding unit in N transmitting element according to selected diversity number.If selected diversity number is less than N, the unit number of using in reality is identical with the diversity number.
Transmitting element carries out diversity transmission to the diversity coded data on respective diversity.
With reference to accompanying drawing 5, receiving course in method of the present invention is described further.
Step 6, diversity reception decoding.
N receiving element detects receive data, when the diversity coded data being detected, it carried out diversity reception, and the diversity coded data that receives is sent to diversity translated code cache module.If the actual diversity coded data number that receives is less than N, the unit number of using in reality is identical with the actual diversity coded data number that receives.
Diversity translated code cache module to each diversity reception to the diversity coded data carry out decoding and buffer memory, generate corresponding diversity decoding data, and send to code to merge and an error-correcting decoding module diversity decoding data.
Step 7, code merges.
The signal-to-noise ratio (SNR) estimation module is estimated the signal to noise ratio of current channel, and signal-to-noise ratio (SNR) estimation information is sent to self-adaptive control module, if do not carry out the transmission of data, self-adaptive control module is estimated current channel condition according to signal-to-noise ratio (SNR) estimation information; If carried out the transmission of data, the comprehensive signal-to-noise ratio (SNR) estimation information of self-adaptive control module, feedback information, the required information such as number of retransmissions of the correct transmission of previous frame data are estimated current channel condition.Yard merging method that self-adaptive control module is selected according to the current channel condition of estimating and current channel condition is complementary: when channel condition is good, use Chase merging method, when bad channel conditions, use steadily increase redundancy IR merging method.Self-adaptive control module merges Method type with selected code to be put into code and merges a control information and send to code to merge and an error-correcting decoding module, and code merges and merges code in control information with the error-correcting decoding module according to code and merge a Method type and select corresponding code merging method.When carrying out the code merging, in a plurality of diversity decoding datas, identical piecemeal can carry out the diversity merging.When having piecemeal to retransmit, the Frame after the error-correcting decoding of the Frame of re-transmission and last transmission merges, to utilize the effective information that increases in the error-correcting decoding process.
Step 8, error-correcting decoding.
Code merges and the error-correcting decoding module is carried out error-correcting decoding to the code merging data, generates corresponding error-correcting decoding data, and the error-correcting decoding data are sent to piecemeal error detection decoding module.
Step 9, piecemeal error detection decoding.
The Data Division module is carried out piecemeal to the error-correcting decoding data, generates corresponding a plurality of deblockings, and a plurality of deblockings are sent in M error detection coding unit unit accordingly.If the deblocking number is less than M, the unit number of using in reality is identical with block count.
The error detection decoding unit carries out error detection decoding to a plurality of deblockings, generates a plurality of error detection decoding piecemeals that comprise right and wrong.
Minute block cache merges module to carrying out buffer memory through the piecemeal after error detection coding, if there is wrong piecemeal in the piecemeal that receives, the piecemeal of wrong piecemeal number is fed back to transmitting terminal as feedback information, the error detection decoding piecemeal of request retransmission mistake.If after all piecemeals all correctly receive or number of retransmissions reaches the maximum of default, each piecemeal is merged into a Frame submits to.
Claims (10)
1. mix automatic repeat request system in a free space optical communication, comprise transmitting portion, receiving unit and control section, wherein:
Described transmitting portion comprises piecemeal error detection coding module, error correction coding module, diversity transmission module; The output of piecemeal error detection coding module connects the input of error correction coding module, and the output of error correction coding module connects the input of diversity transmission module; Described piecemeal error detection coding module is used under self-adaptive control module is controlled, and carries out the error detection coding of self adaptation piecemeal and piecemeal to sending Frame, and retransmits when piecemeal is made mistakes; Described error correction coding module is used for the Frame of piecemeal error detection coding module output is carried out error correction coding; Described diversity transmission module is used for the Frame after error correction coding being carried out adaptive diversity sending under self-adaptive control module is controlled;
Described receiving unit comprises that diversity reception module, code merge and error-correcting decoding module, piecemeal error detection decoding module; The output of described diversity reception module connects the input of code merging and error-correcting decoding module, and code merges and is connected the input of piecemeal error detection decoding module with the output of error-correcting decoding module; Described diversity reception module is used for the Frame that receives is carried out diversity reception and decoding; Described code merges and the error-correcting decoding module, is used under self-adaptive control module is controlled, the diversity reception Frame being carried out code and merges and error-correcting decoding; Described piecemeal error detection decoding module is used for the Frame after error-correcting decoding is carried out piecemeal error detection decoding, and provides corresponding feedback information;
Described control section comprises signal-to-noise ratio (SNR) estimation module, self-adaptive control module; The output of signal-to-noise ratio (SNR) estimation module connects the input of self-adaptive control module, and the output of self-adaptive control module merges and is connected with the input of error-correcting decoding module with input, the input of diversity transmission module, the code of piecemeal error detection coding module respectively; Described signal-to-noise ratio (SNR) estimation module is used for the signal to noise ratio of current channel is estimated; Described self-adaptive control module, be used for the required number of retransmissions of transmission correct in feedback information, signal-to-noise ratio (SNR) estimation information and previous frame data and estimate current channel condition, produce control information according to the current channel condition of estimating, realize to diversity number and coding mode, code in the block count that sends Frame in piecemeal error detection coding module, diversity transmission module merge with the error-correcting decoding module in code merge the adaptive control of mode.
2. the mixing automatic repeat request system for free space optical communication according to claim 1 is characterized in that: the piecemeal error detection coding module in described transmitting portion comprises that Data Division module, a plurality of error detection codings unit and minute block cache merge a module; A plurality of outputs of Data Division module connect the input of a plurality of error detection codings unit, the output of a plurality of error detection codings unit is connected with minute a plurality of inputs of block cache merging module respectively, divide the input of the output connection error correction coding module of block cache merging module, the output of self-adaptive control module is connected with the input that minute block cache merges module with the input of Data Division module respectively; Wherein:
Described Data Division module is used under self-adaptive control module is controlled, and carries out the self adaptation piecemeal to sending Frame, and piecemeal is sent to the error detection coding unit;
Described a plurality of error detection codings unit, be used for each piecemeal is carried out error detection coding, and the piecemeal after error detection coding is sent to a minute block cache merging module, the number of error detection coding unit is the integer greater than 1, its maximum determined by the applied environment of system and partition strategy, and the unit number of using in reality sends Frame with each, and to pass through the actual block count that Data Division module carries out after piecemeal identical;
Described minute block cache merges module, be used for carrying out buffer memory and merging through the block data frame after error detection coding, and the Frame after merging sends to the error correction coding module, under the control of self-adaptive control module, the piecemeal of makeing mistakes retransmitted.
3. the mixing automatic repeat request system for free space optical communication according to claim 1, it is characterized in that: the diversity transmission module in described transmitting portion comprises diversity transmission control module and a plurality of transmitting element; The output of error correction coding module connects the input of diversity transmission control module, a plurality of outputs of diversity transmission control module are connected with the input of a plurality of transmitting elements respectively, and the output of self-adaptive control module connects the input of diversity transmission control module; Wherein:
Described diversity transmission control module is used for carrying out adaptively selected according to the control information of self-adaptive control module to the diversity number of data transmission and the coding mode of each diversity;
Described a plurality of transmitting element, be used for the Frame of each diversity is sent, the number of transmitting element is the integer greater than 1, and its maximum is definite by applied environment and the diversity strategy of system, and the unit number of using in reality is identical with the selected diversity number of diversity transmission control module.
4. the mixing automatic repeat request system for free space optical communication according to claim 1, it is characterized in that: the diversity reception module in described receiving unit comprises a plurality of receiving elements and diversity translated code cache module; The output of a plurality of receiving elements is connected with a plurality of inputs of diversity translated code cache module respectively, and the output of diversity translated code cache module connects the input of code merging and error-correcting decoding module; Wherein:
Described a plurality of receiving element is used for the Frame of each diversity is received, and the number of receiving element is the integer greater than 1, and the number of receiving element is identical with the number of transmitting element in transmission diversity module;
Described diversity translated code cache module is used for the Frame of each diversity reception is carried out decoding and buffer memory, and the Frame after decoding is sent to code merging and error-correcting decoding module.
5. the mixing automatic repeat request system for free space optical communication according to claim 1 is characterized in that: the piecemeal error detection decoding module in described receiving unit comprises that Data Division module, a plurality of error detection decoding unit and minute block cache merge a module; A plurality of outputs of Data Division module are connected with the input of a plurality of error detection decoding units respectively, the output of a plurality of error detection decoding units is connected with minute a plurality of inputs of block cache merging module respectively, and code merges the input that splits module with the output connection data of error-correcting decoding module; Wherein:
Described Data Division module is used for the receiving data frames after error correction coding is carried out piecemeal, and piecemeal is sent to the error detection decoding unit;
Described a plurality of error detection decoding unit, be used for each piecemeal is carried out error detection coding, and the piecemeal after error detection coding is sent to a minute block cache merging module, the number of error detection decoding unit is the integer greater than 1, in receiving unit in the number of error detection decoding unit and transmitting portion the number of error detection coding unit identical;
Block cache merged module in described minute, be used for carrying out buffer memory through the piecemeal after error detection coding, the error detection decoding piecemeal of request retransmission mistake is when all piecemeals all correctly receive or after number of retransmissions reaches the maximum of default, each piecemeal are merged into a Frame submit to.
6. a mixing automatic request retransmission method that is used for free space optical communication, comprise two steps in process of transmitting and receiving course, wherein:
Described process of transmitting comprises the steps:
(1) generate a plurality of deblockings:
The Data Division module receives the control information of self-adaptive control module, carries out the self adaptation piecemeal according to the piecemeal control information in control information to sending Frame, generates corresponding a plurality of deblockings;
(2) generate a plurality of error detection coding piecemeals:
2a) a plurality of error detection coding unit carries out error detection coding to a plurality of deblockings, and for each piecemeal distributes corresponding piecemeal number, generates a plurality of error detection coding piecemeals;
2b) divide block cache to merge module a plurality of error detection coding piecemeals are carried out buffer memory;
(3) merge re-transmission:
3a) divide block cache to merge the control information that module receives self-adaptive control module;
3b) divide block cache to merge whether to exist in the control information that the module judgement receives the piecemeal number that retransmits piecemeal, if exist, will retransmit with number corresponding piecemeal of makeing mistakes of piecemeal; If there is no, divide block cache to merge module with step 2b) in a plurality of error detection coding piecemeals of buffer memory be merged into a Frame, then this Frame is sent to the error correction coding module;
(4) error correction coding:
The error correction coding module is carried out error correction coding to the Frame that receives, and generates corresponding error correction encoded data frame;
(5) adaptive diversity sends:
5a) the diversity transmission control module receives the diversity control information of self-adaptive control module;
5b) the diversity transmission control module is under the control of diversity control information, adopt adaptive approach selection diversity number and the mixing automatic repeat request type that is respectively I, II, III, select coding mode according to selected mixing automatic repeat request type for each diversity, coding mode is consistent with selected mixing automatic repeat request type;
5c) the diversity transmission control module is encoded to the error correction encoded data frame according to selected coding mode, generates corresponding diversity coded frame data;
5d) transmitting element carries out diversity transmission to the diversity coded frame data on respective diversity;
Described receiving course comprises the steps:
(6) diversity reception decoding:
6a) receiving element detects receiving data frames, when the diversity coded frame data being detected, it is carried out diversity reception;
6b) diversity translated code cache module to each diversity reception to the diversity coded frame data carry out decoding, generate corresponding diversity decoding data;
6c) diversity translated code cache module is carried out buffer memory to the diversity decoding data;
(7) code merges:
Code merging and error-correcting decoding module receive the control information of self-adaptive control module, merge control information according to the code in control information the diversity decoding data is carried out code merging processing, generate corresponding code merging data;
(8) error-correcting decoding:
Code merges and the error-correcting decoding module is carried out error-correcting decoding to the code merging data, generates corresponding error-correcting decoding data;
(9) piecemeal error detection decoding:
9a) the Data Division module is carried out piecemeal to the error-correcting decoding data, generates corresponding a plurality of block data frames;
9b) the error detection decoding unit carries out error detection decoding to a plurality of Frame piecemeals, generates a plurality of error detection decoding piecemeals that comprise right and wrong;
9c) divide block cache to merge module to carrying out buffer memory through the piecemeal after error detection coding, the error detection decoding piecemeal of request retransmission mistake, record piecemeal number and the number of retransmissions of correct error detection decoding piecemeal, when all piecemeals all correctly receive or after number of retransmissions reaches the maximum of default, each piecemeal are merged into a Frame submit to.
7. the mixing automatic request retransmission method for free space optical communication according to claim 6, it is characterized in that: the self adaptation piecemeal described in step (1) refers to, the signal-to-noise ratio (SNR) estimation module is estimated the signal to noise ratio of current channel, signal-to-noise ratio (SNR) estimation information is sent to self-adaptive control module, self-adaptive control module is according to the current channel condition of signal-to-noise ratio (SNR) estimation information estimator, carry out piecemeal according to the current channel condition of estimating to sending Frame: if current channel condition is good, reduce block count, if current bad channel conditions, increase block count, the piecemeal number that increases or reduce is consistent with the change trend of current channel condition, self-adaptive control module is put into the piecemeal control information with block count and is sent to the Data Division module, and the Data Division module is carried out piecemeal according to the block count in the piecemeal control information to sending Frame.
8. the mixing automatic request retransmission method for free space optical communication according to claim 6, it is characterized in that: the step of the adaptive approach step 5b) is as follows:
The first step, signal-to-noise ratio (SNR) estimation module estimate the signal to noise ratio of current channel, and signal-to-noise ratio (SNR) estimation information is sent to self-adaptive control module, and self-adaptive control module is according to the current channel condition of signal-to-noise ratio (SNR) estimation information estimator;
Second step, self-adaptive control module is estimated the required number of retransmissions of current correct transmission one Frame according to the current channel condition of estimating, selects the diversity number that equates with the number of retransmissions of estimating;
In the 3rd step, self-adaptive control module is selected the mixing automatic repeat request of three kinds according to the estimated current channel condition of the first step: if current channel condition is good, and Selective type I mixing automatic repeat request; If current channel condition is medium, Selective type II mixing automatic repeat request; If current bad channel conditions, Selective type III mixing automatic repeat request;
The 4th step, self-adaptive control module is put into the diversity control information with selected diversity number with mixing automatic repeat request type and is sent to the diversity transmission control module, the diversity transmission control module is according to the diversity number in the diversity control information and mix the selection that the automatic repeat request type is carried out diversity number and mixing automatic repeat request type, is that each diversity is selected corresponding coding mode according to selected mixing automatic repeat request type.
9. the mixing automatic request retransmission method for free space optical communication according to claim 6, it is characterized in that: the coding mode step 5b) refers to, the diversity transmission control module is selected corresponding residual matrix according to the coding mode that selected type mixing automatic repeat request uses: when adopting type i to mix automatic repeat request, use the residual matrix of regular coding; When adopting Type II or type-iii mixing automatic repeat request, use the residual matrix of rate-matched.
10. the mixing automatic request retransmission method for free space optical communication according to claim 6, it is characterized in that: the code described in step (7) merges processing and refers to, code merges with the error-correcting decoding module according to the code pooling information in control information, the code merging method that selection and current channel condition are complementary, when channel condition is good, use Chase merging method, when bad channel conditions, use steadily increase redundancy merging method; Identical piecemeal carries out diversity and merges, and the Frame after the error-correcting decoding of the Frame of re-transmission and last transmission merges.
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| CN103701562A (en) * | 2013-12-10 | 2014-04-02 | 桂林电子科技大学 | Error control protocol in free space optical communication system |
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| CN107241172A (en) * | 2017-07-17 | 2017-10-10 | 中国联合网络通信集团有限公司 | A kind of data repeating method and access network equipment |
| CN107241172B (en) * | 2017-07-17 | 2019-11-26 | 中国联合网络通信集团有限公司 | A kind of data repeating method and access network equipment |
| WO2022199227A1 (en) * | 2021-03-24 | 2022-09-29 | 华为技术有限公司 | Data transmission method, and communication device and system |
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