CN110213183A - A kind of channel estimation methods of the full duplex relaying system based on Chu sequence - Google Patents
A kind of channel estimation methods of the full duplex relaying system based on Chu sequence Download PDFInfo
- Publication number
- CN110213183A CN110213183A CN201910345811.8A CN201910345811A CN110213183A CN 110213183 A CN110213183 A CN 110213183A CN 201910345811 A CN201910345811 A CN 201910345811A CN 110213183 A CN110213183 A CN 110213183A
- Authority
- CN
- China
- Prior art keywords
- chu sequence
- channel
- full duplex
- signal
- channel estimation
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/024—Channel estimation channel estimation algorithms
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Radio Relay Systems (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
The invention belongs to wireless communication technology fields, disclose a kind of channel estimation methods of full duplex relaying system based on Chu sequence；The use of Chu sequence and OFDM symbol is to send data using non-blind algorithm for estimating, after transmission, the Chu sequence of the Chu sequence and transmitting terminal that receive is subjected to cross-correlation in receiving end, the resulting cross correlation value of the two is the impulse response estimated value of channel；By the Chu sequence phase convolution of the channel value estimated and transmitting terminal, obtained value is reconstruction signal；Signal will be received to subtract each other with reconstruction signal, carry out self-interference elimination.The present invention sets about in terms of theoretical simulation and USRP practice emulation two, co-channel full duplex relaying loop channel simultaneously is estimated as training sequence using Chu sequence, and according to the self-interference channel information estimated, reconstruction signal is produced, the counteracting of self-interference signal is realized.Wherein transmitting terminal and receiving end are transmitted using two USRP, and trunking is simulated using amplification forwarding agreement.
Description
Technical field
The invention belongs to wireless communication technology field more particularly to a kind of full duplex relaying systems based on Chu sequence
Channel estimation methods.
Background technique
Currently, the immediate prior art: having the technology for carrying out channel estimation using m-sequence at present, m-sequence is easy to produce
It is raw, and autocorrelation performance is also relatively good, but cross correlation is undesirable.Using the estimation method based on Chu sequence, can obtain
Lower peak-to-average force ratio, good cross correlation are obtained, and enhances synchronous accuracy.With the development of science and technology, modern communications
Philosophy and technique rapidly promoted, the high-speed communication facility and communication mode of continuous development make people that can more relax in life
It fits, conveniently.But the growth of global communications subscribers exponential form and the continuous rising to communicating requirement, so that script quantity has
Limit, the frequency spectrum resource that can not increase become extremely rare.As long term evolution project (LTE) is answered on a large scale all over the world
With the research work of 5G has also been unfolded.For IMT-2020 (5G) compared with 4G, defining 5G is that the availability of frequency spectrum is higher, transmission is fast
The network communication mode that degree is fast, handling capacity is bigger.So how the wireless communication system needs of a new generation are put forth effort in transmission speed
Degree, using limited frequency spectrum resource, plays higher utilization rate under the higher and higher environment of quality requirement.
The technology of the optimization spectrum efficiency of present mainstream is roughly divided into two classes, the frequency spectrum that one kind passes through raising radiobeam
Utilization rate keeps each channel spectrum occupation rate low, such as typical high frequency modulated technology, spread spectrum, super-broadband tech, MIMO days
Cable architecture.The another kind of utilization rate by improving radio channel, keeps idle time of channel minimum.In the promotion of advanced technology
Under, the method for another kind optimization spectrum efficiency, full duplex relaying technology is also proposed in succession.
It is time division duplex communication mode (TDD) or frequency duplex communications side mostly in present used communication mode
Formula (FDD).Time division duplex sends and receives signal under same frequency, and reception and transmission letter are separated using different time slots
Road.Frequency division duplex handles information using two independent channels, and at different frequencies, transmitting terminal upload information receives at place
Download information needs two frequency channels symmetrical.Time division duplex adds required protection time slot, and frequency division duplex is added
Required guard band, the time resource of two ways or frequency resource relative to co-channel full duplex simultaneously waste half or
More than half.Co-channel full duplex refers to a set of communication equipment or device simultaneously, in the same frequency of same time slot in identical medium
Rate is received and is sent,, can be by the utilization of communications compared with traditional time-division, frequency division duplex by theoretical validation
Rate is doubled with handling capacity, so that communication efficiency be greatly improved, improves system effectiveness.
Meanwhile relay cooperative communication also plays an important role in a communications system.Due to communication media and route of transmission meeting
It changes over time, there is interference and decline in transmission process, signal is caused not transmit correctly.And relay can reduce it is long away from
Interference from transmission, solves the problems, such as interference fading.By increasing relaying in source node and destination node, can effectively expand
The coverage area of big communication system, promotes the transmission performance of wireless communication system.Full duplex relaying system brings high usage etc.
While advantage, can also lead to the problem of one it is crucial, be exactly self-interference.Due to penetrating and receiving with taking place frequently simultaneously, emit signal
Power can generate interference to signal is received much larger than signal, the transmission signal of equipment itself is received, therefore eliminate self-interference and be
The key of full duplex relaying technology.Want eliminate self-interference, self-interference channel must just be estimated, obtain channel parameter with
Self-interference elimination is carried out after characteristic, and wants to offset self-interference signal, it is necessary to which signal phase alignment, latency measurement are correct.Cause
This channel estimation is a highly important ring.
Relaying can be improved the coverage area and handling capacity of channel, can be divided into half-duplex (HD) by existing working method
Repeater mode and full duplex relaying mode (FD), full-duplex communication is compared to can preferably improve frequency spectrum for half-duplex operation
Utilization rate.And trunking scheme can be divided into single-input single-output system (SISO) according to I/O mode and how defeated multi input is
System (MIMO) out, it is generally the case that the transmitting terminal of multi-input multi-output system (MIMO) and receiving end need to configure a plurality of day
Line, in the case where not needing to improve the transmission power of relay and increase its bandwidth cost, this method can be significantly improved
The spectrum efficiency of system.There is remarkable effect for anti-multipath, so as to improve system reliability.And SISO can be in relaying to frequency spectrum
In the case where of less demanding, complete to relay more conveniently.
For full duplex technology, main problem is the inhibition of self-interference.Self-interference inhibits to be divided into three kinds again, space
Domain self-interference inhibits, numeric field self-interference inhibits, analog domain self-interference inhibits.Currently, scientific research personnel is mainly to full duplex relaying
The basic channel estimation that these three suppressor modes of communication and realization well inhibit is studied.To full duplex in some documents
The suppressor mode and channel estimation of relay system different modes are analyzed, and are compared in the performance of different duplexing relayed communicationss
In, the ergodic capacity of full duplex relaying and half-duplex relay on forwarding amplification mode is compared.By in full duplex
After the analysis with half-duplex relay, show that full duplex relaying is better than the critical point of half-duplex relay.It describes in a kind of full duplex
Ergodic capacity and relay ability are compared after transmission plan, and with half-duplex relay, wherein testing two different relaying sides
Formula: amplification forwarding and decoding forward, and have studied carrier wave penetration loss and self-interference inhibition ratio, are obtained by the comparison of the two
The loss of full duplex is less than half-duplex, provides theoretical foundation using full duplex technology to future wireless system by result.
In terms of self-interference inhibition, research is broadly divided into three kinds.A kind of simulation based on single antenna full-duplex transmission system
Self-interference technology for eliminating, separated using radio frequency circulator transmitting and receive signal, with traditional estimation self-interference signal and from
The mode difference that signal subtracts self-interference signal is received, author uses the self-interference signal of antenna-reflected present in circulator,
It goes to reduce the main self-interference signal leaked by transmitting terminal to receiving end.A kind of mixing self-interference cancellation scheme, by two-tap mould
The single antenna full duplex radio station of quasi- Canceller and a digital multipath self-interference arrester composition.Analog domain counteracting partially removes
Strongest part in self-interference, and digital cancellation part has used the receiver of an auxiliary to subtract to collect radio frequency transmissions
Few remaining multipath self-interference.The verification experimental verification under the 20MHZ Long Term Evolution 20dbm signal testing program it is feasible
Property.One kind is under 60GHZ bandwidth, suitable for the digital self-interference Restrain measurement of OFDM full duplex relaying, take it is digital from
Interference is eliminated with convolution correcting vector technology (CVC) and eliminates serious self-interference.Convolution correcting vector can solve circulation and
The not reciprocity problem of linear convolution.
In self-interference inhibition, most important problem is exactly to estimate channel.A kind of new training frame structure is used for full duplex
Amplification forwarding relay system, and the remaining self-interference of system is had estimated, and cascaded channel is used for using Minimum Mean Squared Error estimation
With remaining self-interference channel method, channel relevant parameter is obtained.Using the method that active self-interference inhibits, conventional frame is being used
In the case where structure, a kind of channel estimation methods of wireless rule of new obedience are proposed, and have estimated self-interference channel and its
Time delay.Have studied path transmission loss and the RMS delay spread of co-channel full duplex self-interference channel simultaneously under various varying environments.
A method of the channel estimation in ofdm system, traditional LS channel estimation methods be easy it is affected by noise,
LMMSE and approximation LMMSE channel estimation methods can provide better performance, but more more complicated than LS method, and this article newly proposes
A kind of new low order LMMSE simplifies filtering matrix and diagonal matrix, in addition to ideal channel estimation methods, low order LMMSE letter
Road estimation can provide optimal signal-to-noise ratio, simplify the calculating of channel autocorrelation matrix and provide more preferably multi-path system
Energy.
Wireless channel is an important factor for influencing communication quality, and accurate channel estimation can make system more stable, effective.
High speed data transfer is carried out, the availability of frequency spectrum is improved, just must accurately estimate channel.Since signal will receive in the channel
The influence of shadow effect, multipath fading just have to be understood that the detailed characteristics of channel in order to restore the signal of transmission, be convenient for it
AF panel and decoding afterwards.
Channel estimation is estimated the channel information of wireless channel by receiving signal.If the characteristic of channel is line
Property, channel estimation is exactly to estimate impulse response.Error can be minimized by the channel estimation haveing excellent performance.Mesh
Before, channel estimation is according to characteristic, and there are many mode classifications.It is realized according in time domain realization or frequency domain, time domain channel can be divided into
Algorithm for estimating and channel estimation in frequency domain algorithm.And according to whether can be divided into using known training sequence or pilot frequency sequence
Channel estimation method, Blind channel estimation algorithm, semi-blind channel estimation algorithm based on feedback and the channel estimation based on pilot tone are calculated
Method.Whether parameterized according further to channel, and parametric channel algorithm for estimating and imparametrization channel estimation method can be divided into.
And new transform-domain algorithm can reduce system complexity, and improve accuracy.
Channel blind estimation does not use pilot tone and training sequence, only sends data-signal, is estimated by receiving the characteristic of signal
Count the effective status information of channel.In the case where known channel input and channel output, channel impulse can be gone out with direct estimation
Response.The advantage of Channel blind estimation is exactly not need extra information, only need to can be obtained by higher frequency by sending signal
Utilization rate is composed, the disadvantage is that the complexity of blind estimate is relatively high, the estimation time is longer, and related with the statistical property of signal is sent,
Accuracy is poor, and stability is not high.Therefore in a communications system, less using blind estimate algorithm.
Disadvantage complicated, that calculating magnitude is big is calculated in view of blind estimate, there has been proposed the higher non-blind Channels of computational efficiency
Algorithm for estimating.In principle, blind estimate is to estimate channel by calculating the characteristic of a large amount of input and output signal, therefore such as
Fruit channel variation is very fast, and the accuracy and efficiency of blind estimate can be very low.Rather than the blind estimate availability of frequency spectrum is relatively low, but
It is that complexity is small, and fast speed, obtains letter by sending known training sequence and frequency pilot sign before transmitting data
Road estimation, does not need largely to calculate.But when channel statistic variation is very fast, it is necessary to send a large amount of training sequence
Column, will lead to the shortcomings that transmission speed is slower, this is non-blind estimate.
Semi-blind estimation is the compromise of blind estimate and pilot assistant estimation.It only needs to send some known training symbols and connects
The symbol received can estimate the characteristic of channel.Calculating speed not only can be improved in this mode, but also may not necessarily be with largely
Frequency spectrum send training symbol, keep the availability of frequency spectrum higher, performance is between two kinds of estimation modes.
Non- Blind channel estimation algorithm, the estimation in order to guarantee communication system is accurate, easy, is generally estimated using non-blind Channel
Meter.
In conclusion problem of the existing technology is: current full duplex relaying system due to simultaneously with take place frequently penetrate with
It receives, the power for emitting signal generates interference to signal is received much larger than signal, the transmission signal of equipment itself is received.So that setting
The standby signal that itself sends enters receiving end together with ideal transmission signal, can not demodulate and preferably receive signal.
Solve the difficulty of above-mentioned technical problem: in full duplex relaying communication system, there is strong self-interference signal,
Self-interference can be eliminated using passive removing method directive antenna, but only take it is passive eliminate be can not to transmitting terminal with
What receiving end was effectively isolated, it still needs to using the method actively eliminated, numeric field eliminates interference and analog domain eliminates interference.
Solve the meaning of above-mentioned technical problem: with the development of communication technology, speed and performance of the people to communications
Requirement it is higher and higher, how to be realized in rare frequency spectrum maximized utilization rate at the concern direction of people, while it is same
Frequency resource utilization rate can be doubled in channel full duplex technical know-how, exactly this feature receives it in world wide
Concern.The co-channel full duplex communication technology is considered as improving mass of system in the following 5th generation wireless communication technique (5G) simultaneously
With the effective means of throughput.Meanwhile relaying technique is also considered as a kind of raising future wireless network capacity and coverage area
Effective solution, in space more and more rare today, it is desirable to which building base station on a large scale be already difficult to realize, and relay
Low emissivity, low cost can expand the characteristics of transmission range again and can make up the function of base station well.Relaying is exactly a kind of low
The intermediate node of power consumption is forwarded by handling accordingly by receiving the transmission signal of transmitting terminal, is then forwarded to reception
End, can significantly promote the transmission range of communication and the signal quality of receiving end.So utilizing full duplex relaying communication party
Formula can improve power system capacity to greatest extent, expand the coverage area.But due to the key problem during full duplex relaying
Exactly there is loop self-interference, then effectively inhibits self-interference just into key technology therein.In effectively eliminating
After the self-interference signal of rear channel, need to carry out channel estimation to relaying loop channel to carry out numeric field elimination.
Summary of the invention
In view of the problems of the existing technology, the present invention provides a kind of full duplex relaying systems based on Chu sequence
Channel estimation methods.
The invention is realized in this way a kind of channel estimation methods of the full duplex relaying system based on Chu sequence, described
The channel estimation methods of full duplex relaying system based on Chu sequence include:
The first step is to send data using Chu sequence and OFDM symbol, by transmission using non-blind algorithm for estimating
Afterwards, the Chu sequence of the Chu sequence and transmitting terminal that receive is subjected to cross-correlation in receiving end, the resulting cross correlation value of the two is
The impulse response estimated value of channel；
Second step, by the Chu sequence phase convolution of the channel value estimated and transmitting terminal, obtained value is to rebuild letter
Number；Signal will be received to subtract each other with reconstruction signal, carry out self-interference elimination.
Further, the channel estimation methods of the full duplex relaying system based on Chu sequence carry out letter using Chu sequence
Road estimation；The following mathematical expression subrepresentation of Chu sequence:
Wherein, q is arbitrary integer, WNIt is basis n times square root；
R represents the group number of original series, is the positive integer relatively prime with N；Q is different from the value of r, resulting Chu sequence
It is different；
Taking not is root sequence by the Chu sequence shifted；When N is even number, q=1, r=1, auto-correlation are taken are as follows:
Wherein m indicates the number of displacement,The sequence being conjugated after being displacement m；
When N is odd number, q=1, r=1 are equally taken, identical result is obtained.
Further, the channel estimation methods of the full duplex relaying system based on Chu sequence are by channel to received
OFDM symbol is handled, by the signal demodulated and the initial detecting for sending signal and carrying out the bit error rate, the principle of channel estimation
Are as follows:
In formula, z is the Chu sequence sent, and r is the Chu sequence of receiving end；The impulse response of channel is expressed as:
The estimation to channel impulse response is completed in the time domain using Chu sequence, whereinFor the channel of estimation；It will estimate
It counts outWith send signal phase convolution:
The reconstruction signal estimated, the two is subtracted each other, and obtains the result of self-interference elimination.
Another object of the present invention is to provide the channel estimations of the full duplex relaying system described in one kind based on Chu sequence
Application of the method in the fixed covering scene of wireless relay, user terminal with base station is direct-connected cannot achieve through base station-relaying-use
The mode of family terminal connects.
Another object of the present invention is to provide the channel estimations of the full duplex relaying system described in one kind based on Chu sequence
Application of the method in heavy construction in-door covering scene, by disposing trunking at building external, subway.
Another object of the present invention is to provide the channel estimations of the full duplex relaying system described in one kind based on Chu sequence
Application of the method in provisional covering and urgency communication scene, communication disruption place trunking.
Another object of the present invention is to provide the channel estimations of the full duplex relaying system described in one kind based on Chu sequence
Application of the method in transit equipment covering scene, user on a vehicle when, generate switching request in the process of moving；
After relaying access, the connection of receiving end and trunking.
In conclusion advantages of the present invention and good effect are as follows: the present invention emulates two sides from theoretical simulation and USRP practice
Face is set about, and is estimated as training sequence co-channel full duplex relaying loop channel simultaneously using Chu sequence, and according to estimation
Self-interference channel information out, produces reconstruction signal, realizes the counteracting of self-interference signal.Wherein transmitting terminal and receiving end benefit
It is transmitted with two USRP, and trunking is simulated using amplification forwarding agreement.
The present invention carries out channel estimation using Zadoff-Chu sequence (abbreviation Chu sequence).There are two features for Chu sequence:
It is permanent envelope in time-domain and frequency-domain, makes it have stronger anti-interference ability；The autocorrelation performance of Chu sequence only has zero point
Zero is not taken, other points are all zero, and phase characteristic is good.Due to the two characteristics, can be compressed with large-scale application in pulse radar
Equipment, spread spectrum technic and ofdm communication system.
The present invention is based on general software radio peripheral hardwares (USRP) to have carried out reality to the channel estimation methods by verifying
The estimation for relaying loop channel, carries out sending and receiving Chu sequence by USRP, using Chu sequence as training sequence, uses
Chu sequence and the mode for receiving signal cross-correlation can estimate the gain information of channel, and can be accurate by signal processing method
Reduction receives signal, the final elimination for realizing self-interference signal.
The wireless relay that the present invention uses due to it is at low cost, convenient for deployment etc. characteristics, can be used for following scene:
Fixed covering scene: wireless relay can provide stable, continual covering, can equally expand covering with base station
Range, raising power system capacity and handling capacity, but energy minimization cost, and do not need to be routed.Trunking can be placed on
On the high buildings such as street lamp, roof, this mode can guarantee the radio link quality in communication with lower cost, solve
The problems such as edge customer signal fadeout is big, can not receive signal, and realize the covering of shadow region.User terminal is straight with base station
Even insurmountable problem can be solved by way of base station-relaying-user terminal, not only increase capacity, but also expand
Coverage area.
Heavy construction in-door covering: when signal frequency range is higher, when its pass through building when, be lost it is larger, decline compared with
By force, such as inside heavy construction, subway tunnel.In this case, construction base station is unreasonable, can be by outer in building
Trunking is disposed at portion, subway, and interior is made to remain to receive normal signal.
Provisional covering and urgency communication: it when emergency case, which occur, in some areas leads to communication disruption, can temporarily put
Set trunking.Such as when earthquake, flood major disaster occurs, provisional communication can be restored using trunking.Meanwhile
It,, can be by traffic balance to adjacent base using relaying when large-scale game such as concert under the situation that some interim telephone traffics increase severely
It stands.
The covering of transit equipment: when user is on the vehicles such as automobile, train, it can generate cut in the process of moving
Request is changed, biggish load is caused to base station equipment, after relaying access, the connection of receiving end and trunking is more steady
Connecting path that is fixed, changing with the only trunking and base station of switching.
Detailed description of the invention
Fig. 1 is the channel estimation methods process of the full duplex relaying system provided in an embodiment of the present invention based on Chu sequence
Figure.
Fig. 2 is Chu sequence autocorrelation performance schematic diagram provided in an embodiment of the present invention.
Fig. 3 is Chu sequence perseverance envelope trait schematic diagram provided in an embodiment of the present invention.
Fig. 4 is the bit error rate schematic diagram of the different beta provided in an embodiment of the present invention under 50-50-50cm distance.
Fig. 5 is full duplex relaying transmission pictorial diagram provided in an embodiment of the present invention.
Fig. 6 is provided in an embodiment of the present invention by full duplex relaying reception signal (Chu sequence) schematic diagram.
Fig. 7 is full duplex relaying characteristic of channel schematic diagram provided in an embodiment of the present invention.
Fig. 8 is the comparison diagram provided in an embodiment of the present invention for receiving signal and reconstruction signal.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to embodiments, to the present invention
It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to
Limit the present invention.
Since nearly half a century.Development communication technologies are rapid, and communication requirement is continuously improved in user, limited frequency spectrum resource
Become extremely nervous.Therefore, spectrum efficiency is improved preferably to meet the problem of user demand is urgent need to resolve.In advanced biography
Under the promotion of defeated, antenna and signal processing technology, there has been proposed one kind can the same time using same frequency send and
Received full duplex technical solution.And the capacity and coverage area of future wireless network can be improved in relaying technique.It is theoretically complete
The capacity of duplexing relay system is doubled than half-duplex relay system, this is extremely in the cellular system for taking base station as relaying
It is crucial and merit attention.One main problem of full duplex relaying system is exactly the elimination of self-interference, eliminates the pass of self-interference
Key is exactly to estimate accurate channel.Full duplex relaying node loop channel estimation technique of the invention, utilizes training sequence pair
Channel is estimated, realizes that self-interference inhibits；According to the characteristic of Zadoff-Chu sequence, the channel based on Chu sequence is proposed
Estimation method, and emulated using Matlab.Using USRP real-time Transmission Chu sequence, using Chu sequence as training sequence
Numeric field channel estimation is carried out, and eliminates interference, has obtained simulation result with Matlab.
Application principle of the invention is explained in detail with reference to the accompanying drawing.
As shown in Figure 1, the channel estimation methods of the full duplex relaying system provided in an embodiment of the present invention based on Chu sequence
The following steps are included:
S101: using non-blind algorithm for estimating, the use of Chu sequence and OFDM symbol is to send data, after transmission,
The Chu sequence of the Chu sequence and transmitting terminal that receive is subjected to cross-correlation in receiving end, the resulting cross correlation value of the two is channel
Impulse response estimated value；
S102: by the Chu sequence phase convolution of the channel value estimated and transmitting terminal, obtained value is reconstruction signal；
Signal will be received to subtract each other with reconstruction signal, i.e. progress self-interference elimination.
Application principle of the invention is further described with reference to the accompanying drawing.
The present invention carries out channel estimation using Zadoff-Chu sequence (abbreviation Chu sequence).There are two features for Chu sequence:
It is permanent envelope in time-domain and frequency-domain, has strong anti-interference ability；The autocorrelation performance of Chu sequence only has zero point not take
Zero, other points are all zero, and phase characteristic is good.Due to the two characteristics, can with large-scale application in pulse radar compression device,
Spread spectrum technic and ofdm communication system.
1, the characteristic and verifying of CHU sequence, Chu sequence can use following mathematical expression subrepresentation:
Wherein, q is arbitrary integer, WNIt is basis n times square root；
R represents the group number of original series, is the positive integer relatively prime with N.Q is different from the value of r, resulting Chu sequence
It is different.
Taking not is root sequence by the Chu sequence shifted.When N is even number, q=1, r=1, auto-correlation are taken are as follows:
Wherein m indicates the number of displacement,The sequence being conjugated after being displacement m.
When N is odd number, q=1, r=1 are equally taken, identical result can be obtained.
The characteristic of Chu sequence can be summed up from the formula present invention:
(1) permanent envelope trait: no matter what value N takes, and Chu sequence amplitude is constant.As shown in Fig. 2, working as N=1280
When, amplitude stabilization is about 1.
(2) good autocorrelation performance and cross correlation: and original as shown in figure 3, after Chu sequential shift is m any
Root sequence it is uncorrelated, only in m=0, get peak value N.Take different r and q, Chu cross correlation value at 0 above and below fluctuate.
(3) low peak average ratio: since Chu sequence is permanent envelope, the ratio of peak value and mean value is lower, and difference is smaller.
(4) good time-frequency characteristic: being still Chu sequence after Chu sequence Fourier transformation and inverse Fourier transform.
2, the channel estimation test based on Chu sequence
In channel estimation test, the present invention uses Chu sequence for training sequence, special using its cyclic shift in receiving end
Property estimates channel information, and recovers transmission data.Its specific test thought is as follows:
Firstly, the use of Chu sequence and OFDM symbol is to send data using non-blind algorithm for estimating, after transmission,
The Chu sequence of the Chu sequence and transmitting terminal that receive is subjected to cross-correlation in receiving end, the resulting cross correlation value of the two is channel
Impulse response estimated value.Again by the Chu sequence phase convolution of the channel value estimated and transmitting terminal, obtained value is to rebuild
Signal, and signal will be received and subtracted each other with reconstruction signal, that is, carry out self-interference elimination.And the present invention passes through channel to received
OFDM symbol is handled, and by the signal demodulated and the initial detecting for sending signal and carrying out the bit error rate, can be reacted channel and be estimated
The accuracy of meter.The principle of its channel estimation are as follows:
In formula (3), z is the Chu sequence sent, and r is the Chu sequence of receiving end.When the value of noise is much smaller than reception signal
Value when, so that it may ignoreInfluence, so the impulse response of channel can be expressed as:
The estimation to channel impulse response is completed in the time domain using Chu sequence, whereinFor the channel of estimation.It will estimate
It counts outWith transmission signal phase convolution, it may be assumed that
It can be obtained by the reconstruction signal estimated, the two subtracted each other, the result of self-interference elimination can be obtained.
Application effect of the invention is explained in detail below with reference to emulation.
1, the channel estimation test based on USRP
Test is based on Matlab and USRPB210 platform, has used directional aerial, and amplifier serves as amplification forwarding relaying, makes
It is used to realize the reception and transmission of signal with two USRPB210, the channel of transmission is estimated, and has detected to utilize and estimate
Error rates of data after the channel of meter.
1.1, USRP experimental enviroment is debugged
In order to make in test mostly through less, channel estimation is more accurate, and the present invention needs to carry out the experimental enviroment of USRP
Setting.Firstly, present invention utilizes directive antennas, and keep reception parallel with transmission antenna, self-interference is carried out in spatial domain
Inhibit.Secondly, the present invention joined amplifier between directional aerial, amplification forwarding agreement is used to the signal of transmission,
And according to the distance between distinct device, first carry out the qpsk error rate test of different distance, select the characteristic of channel preferably away from
From test measures transmitting terminal-receiving antenna distance, receiving antenna-transmission antenna distance, transmission antenna-reception respectively
The distance at end, and control under different distances the gain beta (1~26) of amplifier, measures distance in 50-50-50 respectively,
Bit error rate situation under 50-50-100,50-55-55,50-55-100cm, as shown in Figure 4.Therefore, experimental enviroment of the invention
Final choice transmitting terminal and receiving antenna distance be 50cm, receiving antenna and transmission antenna distance be 50cm, transmission antenna with
Receiving end distance is to measure under 50cm distance, and be taken as 14, in the case, channel to the attenuation coefficient β of amplifier
The bit error rate is lower, the data sent conducive to reduction.As shown in Figure 5.
1.2, the channel estimation based on Chu sequence
After experimental enviroment has been got well in erection, the present invention will drive USRP to carry out full duplex relaying loop letter using Matlab
Entire channel loop is estimated in the estimation in road.Firstly, the present invention is existed using UHD (USRP Hardware Drivers)
Transmitting terminal establish send class signal radio_Tx, wherein the signal sent be formula (3-9) in q=0, the Chu sequence of r=1,
Middle length is 1280, and the present invention takes signal the sampling of 1600e^3HZ, by starting, USRP sends signal, same
When also utilize Matlab driving USRP to establish in receiving end in the other end to receive class signal radio_Rx, the two is same in the same time
One frequency is sent and received.
Signal is preferably received in order to acquire characteristic, the transmission of 300 signals has been carried out using USRP in transmitting terminal, has passed through
The detection of correlation selects the maximum reception signal of one of correlation to be analyzed.
As shown in fig. 6, being the signal that is received after full duplex relaying of sequence of a N=1280 in figure, due to making an uproar
The influence of sound, the waveform for receiving signal can float up and down.
It is come out after receiving end regenerates Chu sequence identical with transmitting terminal, then by the Chu sequential extraction procedures of receiving end,
Using xcorr function by the Chu sequence cross-correlation of the Chu sequence of receiving end and transmitting terminal, cross correlation value maximum is therefrom chosen, it is special
The optimal channel parameter of property, for eliminating self-interference signal, the channel after interception is as shown in Figure 7.
By the Chu sequence phase convolution of obtained channel parameter ht and transmitting terminal, the reconstruction signal estimated, and will connect
The collection of letters number subtracts reconstruction signal, self-interference error can be obtained, as shown in Figure 8.
Reconstruction signal and reception signal as shown in Figure 8 are essentially identical, and the error after the two is subtracted each other is smaller, basic to can be ignored not
Meter.Therefore, estimated channel information is accurately, to can be used for signaling protein14-3-3.
The present invention simultaneously devises the channel estimation methods based on Chu sequence on the basis of USRPB210 equipment and disturbs inhibition side
Method.The present invention tests the environment of USRP first, has selected to test correlation properties in the lower situation of the bit error rate.In benefit
After estimating channel information with USRP and Matlab, the present invention has rebuild signal, and has obtained self-interference letter by subtracting each other
Number.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.
Claims (7)
1. a kind of channel estimation methods of the full duplex relaying system based on Chu sequence, which is characterized in that described to be based on Chu sequence
The channel estimation methods of the full duplex relaying system of column include:
The first step is to send data using Chu sequence and OFDM symbol using non-blind algorithm for estimating, after transmission,
The Chu sequence of the Chu sequence and transmitting terminal that receive is carried out cross-correlation by receiving end, and the resulting cross correlation value of the two is channel
Impulse response estimated value；
Second step, by the Chu sequence phase convolution of the channel value estimated and transmitting terminal, obtained value is reconstruction signal；It will
It receives signal to subtract each other with reconstruction signal, carries out self-interference elimination.
2. the channel estimation methods of the full duplex relaying system based on Chu sequence as described in claim 1, which is characterized in that
The channel estimation methods of the full duplex relaying system based on Chu sequence carry out channel estimation using Chu sequence；Chu sequence
With following mathematical expression subrepresentation:
Wherein, q is arbitrary integer, WNIt is basis n times square root；
R represents the group number of original series, is the positive integer relatively prime with N；Q is different from the value of r, and resulting Chu sequence is also different；
Taking not is root sequence by the Chu sequence shifted；When N is even number, q=1, r=1, auto-correlation are taken are as follows:
Wherein m indicates the number of displacement,The sequence being conjugated after being displacement m；
When N is odd number, q=1, r=1 are equally taken, identical result is obtained.
3. the channel estimation methods of the full duplex relaying system based on Chu sequence as described in claim 1, which is characterized in that
The channel estimation methods of the full duplex relaying system based on Chu sequence by channel to received OFDM symbol at
Reason, by the signal demodulated and the initial detecting for sending signal and carrying out the bit error rate, the principle of channel estimation are as follows:
In formula, z is the Chu sequence sent, and r is the Chu sequence of receiving end；The impulse response of channel is expressed as:
The estimation to channel impulse response is completed in the time domain using Chu sequence, whereinFor the channel of estimation；It will estimate
'sWith send signal phase convolution:
The reconstruction signal estimated, the two is subtracted each other, and obtains the result of self-interference elimination.
4. a kind of channel estimation methods of the full duplex relaying system as described in claims 1 to 3 any one based on Chu sequence
Application in the fixed covering scene of wireless relay, which is characterized in that user terminal with base station is direct-connected cannot achieve through base station-
Relaying-user terminal mode connects.
5. a kind of channel estimation methods of the full duplex relaying system as described in claims 1 to 3 any one based on Chu sequence
Application in heavy construction in-door covering scene, which is characterized in that set by disposing relaying at building external, subway
It is standby.
6. a kind of channel estimation methods of the full duplex relaying system as described in claims 1 to 3 any one based on Chu sequence
Application in provisional covering and urgency communication scene, which is characterized in that communication disruption places trunking.
7. a kind of channel estimation methods of the full duplex relaying system as described in claims 1 to 3 any one based on Chu sequence
Application in transit equipment covering scene, which is characterized in that user on a vehicle when, in the process of moving generate cut
Change request；After relaying access, the connection of receiving end and trunking.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910345811.8A CN110213183A (en) | 2019-04-26 | 2019-04-26 | A kind of channel estimation methods of the full duplex relaying system based on Chu sequence |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910345811.8A CN110213183A (en) | 2019-04-26 | 2019-04-26 | A kind of channel estimation methods of the full duplex relaying system based on Chu sequence |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110213183A true CN110213183A (en) | 2019-09-06 |
Family
ID=67786437
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910345811.8A Pending CN110213183A (en) | 2019-04-26 | 2019-04-26 | A kind of channel estimation methods of the full duplex relaying system based on Chu sequence |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110213183A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110572797A (en) * | 2019-10-28 | 2019-12-13 | 西安电子科技大学 | Route-finding network topology structure for emergency communication and routing method thereof |
| CN113746615A (en) * | 2021-07-30 | 2021-12-03 | 天津师范大学 | Method for switching communication node between full-duplex mode and half-duplex mode |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101877594A (en) * | 2009-04-30 | 2010-11-03 | 杨浩 | Receiver algorithm for mobile communication random access introduction burst |
| CN106301457A (en) * | 2016-10-08 | 2017-01-04 | 西安电子科技大学 | Self-interference removing method in bi-directional full-duplex MIMO relay communications system |
| CN107154818A (en) * | 2017-04-07 | 2017-09-12 | 西安电子科技大学 | Co-channel full duplex bi-directional relaying transmission method while based on single carrier frequency domain equalization |
| CN107171997A (en) * | 2017-05-08 | 2017-09-15 | 北京科技大学 | A kind of numeric field self-interference removing method of full-duplex communication and a kind of base station |
| CN107210907A (en) * | 2015-02-09 | 2017-09-26 | 华为技术有限公司 | The system and method for the training signal of full duplex communication system |
| CN107359977A (en) * | 2017-07-17 | 2017-11-17 | 清华大学 | CDMA is with frequency with code wireless full-duplex communication channel self-interference removing method |
| CN107534626A (en) * | 2015-04-23 | 2018-01-02 | 华为技术有限公司 | The channel impulse of full-duplex communication network |
| US20180026773A1 (en) * | 2015-01-23 | 2018-01-25 | Lg Electronics Inc. | Method for estimating, by device using fdr scheme, non-linear self-interference signal channel |
| CN108494466A (en) * | 2018-04-20 | 2018-09-04 | 西安电子科技大学 | The full duplex relaying transmission method that reconstruct is offset is interfered based on loop |
| CN108599789A (en) * | 2018-03-30 | 2018-09-28 | 清华大学 | Full duplex radio frequency self-interference suppressing method and device |
-
2019
- 2019-04-26 CN CN201910345811.8A patent/CN110213183A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101877594A (en) * | 2009-04-30 | 2010-11-03 | 杨浩 | Receiver algorithm for mobile communication random access introduction burst |
| US20180026773A1 (en) * | 2015-01-23 | 2018-01-25 | Lg Electronics Inc. | Method for estimating, by device using fdr scheme, non-linear self-interference signal channel |
| CN107210907A (en) * | 2015-02-09 | 2017-09-26 | 华为技术有限公司 | The system and method for the training signal of full duplex communication system |
| CN107534626A (en) * | 2015-04-23 | 2018-01-02 | 华为技术有限公司 | The channel impulse of full-duplex communication network |
| CN106301457A (en) * | 2016-10-08 | 2017-01-04 | 西安电子科技大学 | Self-interference removing method in bi-directional full-duplex MIMO relay communications system |
| CN107154818A (en) * | 2017-04-07 | 2017-09-12 | 西安电子科技大学 | Co-channel full duplex bi-directional relaying transmission method while based on single carrier frequency domain equalization |
| CN107171997A (en) * | 2017-05-08 | 2017-09-15 | 北京科技大学 | A kind of numeric field self-interference removing method of full-duplex communication and a kind of base station |
| CN107359977A (en) * | 2017-07-17 | 2017-11-17 | 清华大学 | CDMA is with frequency with code wireless full-duplex communication channel self-interference removing method |
| CN108599789A (en) * | 2018-03-30 | 2018-09-28 | 清华大学 | Full duplex radio frequency self-interference suppressing method and device |
| CN108494466A (en) * | 2018-04-20 | 2018-09-04 | 西安电子科技大学 | The full duplex relaying transmission method that reconstruct is offset is interfered based on loop |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110572797A (en) * | 2019-10-28 | 2019-12-13 | 西安电子科技大学 | Route-finding network topology structure for emergency communication and routing method thereof |
| CN110572797B (en) * | 2019-10-28 | 2021-06-25 | 西安电子科技大学 | Route-finding network topology structure for emergency communication and routing method thereof |
| CN113746615A (en) * | 2021-07-30 | 2021-12-03 | 天津师范大学 | Method for switching communication node between full-duplex mode and half-duplex mode |
| CN113746615B (en) * | 2021-07-30 | 2023-09-01 | 天津师范大学 | Method for switching communication node between full duplex mode and half duplex mode |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8428040B2 (en) | Reception apparatus and reception method for setting a format per divided band | |
| US9014149B2 (en) | Communication apparatus and base station apparatus | |
| CN101534269B (en) | Underwater sound communication system | |
| CN101753176B (en) | Interference rejection combining method and system | |
| CN104767545A (en) | Method and apparatus for communication with high interferences | |
| CN102860064A (en) | Channel estimation and data detection in a wireless communication system in the presence of inter-cell interference | |
| CN101729140A (en) | Channel calibration method and device | |
| US20050041693A1 (en) | Method and apparatus for frequency synchronization in MIMO-OFDM wireless communication systems | |
| CN1941663B (en) | Multi-antenna channel duplicating method and wavebeam shaping method | |
| CN102571659B (en) | Interference noise estimation and interference inhibition method and corresponding system | |
| CN107733513B (en) | Transmission method and device for downlink received beam training signal | |
| CN103716263B (en) | Based on the parallel efficient pilot frequency system offset in large-scale multi-antenna system | |
| CN101411151B (en) | Radio reception device, radio transmission device, radio base station, reception method, and transmission method | |
| Mehlführer et al. | Measurement-based performance evaluation of MIMO HSDPA | |
| US8654667B2 (en) | Method for demodulating data and demodulating apparatus based on a downlink transmit diversity mode in a LTE system | |
| CN102710390B (en) | The method and apparatus of precoding in a kind of multi-user MIMO system | |
| CN110213183A (en) | A kind of channel estimation methods of the full duplex relaying system based on Chu sequence | |
| CN101807979A (en) | Method for multi-user pre-coding based on single-antenna power constraint in wireless communication | |
| CN101577968A (en) | Method, system and device for obtaining descending channel information | |
| CN106160814B (en) | A kind of multi-base station cooperative downlink transmission method based on interference alignment techniques | |
| Shao et al. | Downlink multicell MIMO-OFDM: An architecture for next generation wireless networks | |
| CN103283197A (en) | Covariance estimation method for space-requency domain equalization and apparatus and system associated therewith | |
| CN103379048A (en) | Channel estimation and detection method and base station | |
| CN103873125B (en) | The launching technique and equipment of downstream signal in a kind of multiaerial system | |
| CN102447658B (en) | Method and device for suppressing and merging interference |
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 | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20190906 |