CN106027166B - A kind of super broad band radio communication system noise suppressing method based on time reversal - Google Patents
A kind of super broad band radio communication system noise suppressing method based on time reversal Download PDFInfo
- Publication number
- CN106027166B CN106027166B CN201610352168.8A CN201610352168A CN106027166B CN 106027166 B CN106027166 B CN 106027166B CN 201610352168 A CN201610352168 A CN 201610352168A CN 106027166 B CN106027166 B CN 106027166B
- Authority
- CN
- China
- Prior art keywords
- signal
- time reversal
- time
- discrete
- communication system
- 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.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B14/00—Transmission systems not characterised by the medium used for transmission
- H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
- H04B14/026—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation using pulse time characteristics modulation, e.g. width, position, interval
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B14/00—Transmission systems not characterised by the medium used for transmission
- H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
- H04B14/04—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation using pulse code modulation
- H04B14/046—Systems or methods for reducing noise or bandwidth
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
- Noise Elimination (AREA)
Abstract
The invention belongs to the communications fields, a kind of super broad band radio communication system noise suppressing method based on time reversal is provided, this method receives the noise profile feature of signal according to time reversal, it receiver is received into the numerical value of currentitem and its all numerical value previous in discrete-time signal sequence mutually adds up and obtain and formula, then should be exported with formula as this reception signal；Successively processing is overlapped to the discrete signal each single item received again, obtains that treated and receive signal, then normal signal demodulation is carried out to the signal.Receiving end noise level is effectively reduced by the pretreatment to signal is received in the present invention, increases time reversal communication frame length, to improve signal transmission quality and transmission rate, that is, improves the communication performance of time reversal communication system.
Description
Technical field
The invention belongs to the communications field, it is related to the super broad band radio communication system noise suppressing method based on time reversal.
Background technique
Time reversal (Time Reversal, TR) is initially a kind of signal processing technology in acoustics, it can make uniform non-
The sound wave propagated in homogeneous medium realizes the synchronizing focus of time and space；2004, time reversal technology was introduced in electromagnetism
Field, people start to explore application of the time reversal technology in electromagnetic wave system.The study found that utilizing time reversal technology
The time and spatial synchronization that electromagnetic wave may be implemented focus, and this unique physical property allows time reversal electromagnetism by widely
Among the various fields of electronic information science & technology, such as high-speed high capacity wireless data transmission, space super high power
Synthesis, super-resolution target acquisition etc..
Be denoted as point P equipped with a target point, if having dry aerial constitute time reversal mirror (TRM), time reversal it is general
Process can be briefly described as following steps:
Step 1, target point P first emit a direct impulse signal, and time reversal mirror receives signal；
Step 2, time reversal mirror overturn the signal received on a timeline；
Step 3, time reversal mirror emit the signal after above-mentioned overturning again；
The signal in time and spatial synchronization focusing can be received at step 4, target point P position.
By the wireless propagation environment between target point and time reversal mirror, it is modeled as the filtering that time domain impulse response is h (t)
Device, then last received signal can indicate in step 4 are as follows:
Wherein, x (t) is transmitting signal, and n (t) is white Gaussian noise,Indicate convolution algorithm.
And the communication system based on time reversal technology, it is that will receive the detection of target point P transmitting in time reversal mirror
After pulse signal, respective channel impulse response is extracted, and it is overturn on a timeline, using obtained signal as prefilter
Tap；In data transfer phase, by the data for needing to send by the prefilter, i.e., with the channel impulse after time reversal
Response carries out convolution and obtains transmitting signal, is emitted later by each time reversal mirror.
The communication technology that ultra wide band (UWB) wireless communication system is received significant attention as wireless communication field in recent years,
With high message capacity, the particular advantages such as new frequency spectrum (compatible other wireless communication system frequency spectrums), good confidentiality are not needed, still
Wireless communications environment is extremely complex, and thus bring multi-path jamming seriously affects communication quality.It is subsequent in order to overcome the problems, such as this
The efficient transmission of radio links technology of environment self-adaption ultra wide band based on time reversal is researched and proposed, which can greatly mention
The environment self-adaption ability of high ultra-wideband communication system.Time reversal technology can be by the signal in paths different in arbitrarily complicated environment
Energy is pooled in the same spatial point in synchronization, and this Space Time synchronizing focus characteristic can not only efficiently use multipath
Effect improves signal-to-noise ratio, reduces intersymbol interference, improves the transmission rate and distance of communication system, but also may be implemented wireless
Secret communication, inhibition co-channel interference, raising power system capacity etc., and do not increase Receiver Complexity；Therefore there is wide answer
Use prospect.
The modulation technique that ultra wide band (UWB) wireless communication system uses at present is mainly pulse position modulation (PPM) and arteries and veins
Rush amplitude modulation (PAM)；Wherein PPM can remove the energy spikes of UWB spectrum, keep power spectrum more flat, while being also able to achieve
Multiple access；But research finds to receive the noise level meeting of signal in the time reversal UWB communication system merely using PPM modulation
As the bit number of transmission increases and increase, the bit number that transmitter is once sent is more, and noise level is higher, signal-side
Valve ratio can run down, so as to cause the increase of the bit error rate；And up to the present, it can solve there is no effective processing method
The problem.
Summary of the invention
It is an object of the invention to the defect for background technique, to provide a kind of super wideband wireless based on time reversal logical
Believe system noise suppressing method, this method receives the noise profile feature of signal according to time reversal, by reception signal
Processing reduces receiving end noise level, improves the signal secondary lobe ratio SSR for receiving signal, improves the logical of time reversal communication system
Believe performance.
To achieve the above object, the invention adopts a technical scheme as:
A kind of super broad band radio communication system noise suppressing method based on time reversal, comprising the following steps:
The pulse signal that receiver receives is obtained discrete-time signal sequence x later by analog-to-digital conversion by step 1,
It is n total to set discrete signal sequence x, then:
X=[x [1], x [2], x [3] ..., x [k] ..., x [n]]
Step 2, by each single item x [k] in discrete-time signal sequence x, k=1,2..., n and before it all numerical value into
Row is cumulative to be obtained and formula y [k], it may be assumed that
To obtain discrete-time signal sequences y: y=[y [1], y [2], y [3] ..., y [k] ..., y [n]], export
Discrete-time signal sequences y carries out signal demodulation.
Effect of the invention is that:
A kind of super broad band radio communication system noise suppressing method based on time reversal is provided, this method connects receiver
Receive in discrete-time signal sequence that the numerical value of currentitem and its all numerical value previous are mutually cumulative to be obtained and formula, it then should be with
Formula receives signal output as this；Successively processing is overlapped to the discrete signal each single item received again, is obtained everywhere
Reception signal after reason, then normal signal demodulation is carried out to the signal, therefore the present invention is known as preceding paragraph summation (Former-
Term Accumul ation).Receiving end noise level is effectively reduced by the pretreatment to signal is received in the present invention, increases
Time reversal communication frame length, to improve signal transmission quality and transmission rate, i.e., raising time reversal communication system is logical
Believe performance.
Detailed description of the invention
Fig. 1 is system block diagram.
Fig. 2 is that a typical time reversal receives signal waveform.
Fig. 3 is PPM modulation schematic illustration.
Fig. 4 is simulation architecture schematic diagram in embodiment 1.
Fig. 5 is pulse position modulation code in embodiment 1.
Fig. 6 is channel impulse response after overturning in embodiment 1.
Fig. 7 is that time reversal mirror emits signal in embodiment 1.
Fig. 8 is that target point receives signal in embodiment 1.
Fig. 9 is the reception signal in embodiment 1 after preceding paragraph accumulation process.
Figure 10 is 20 bit datas in embodiment 2.
Figure 11 is 20 bit modulations in embodiment 2.
Figure 12 is TRM each unit signal to be transmitted in embodiment 2.
Figure 13 is that target point receives signal in embodiment 2.
Figure 14 is preceding paragraph accumulation result in embodiment 2.
Figure 15 is reception signal, main lobe and the first secondary lobe in embodiment 2 after preceding paragraph accumulation process.
Figure 16 is initial signal and the main secondary lobe ratio after accumulation process in embodiment 2.
Specific embodiment
The present invention is described in further details in the following with reference to the drawings and specific embodiments.
The super broad band radio communication system noise suppressing method based on time reversal provided in embodiment, this method according to
Time reversal receives the noise profile feature of signal, by the processing to signal is received, receiving end noise level is reduced, to subtract
Low error rate of system.The system block diagram of its process as shown in Figure 1, wherein dotted line frame 1. in be to be based on method proposed by the invention
Receiver realize increased part,For adder, 2. by increase " feedback " detail, and the signal of feedback is input to and is added
In musical instruments used in a Buddhist or Taoist mass, realize that current input signal numerical value is added with previous item numerical value.And at this time detail 2. in previous item numerical value, due to upper
The processing of one wheel, all data is cumulative before being, carries out real-time preceding paragraph accumulation process to reception signal to realize.
By taking 4 units are constituted time reversal mirror as an example, signal is received using a typical time reversal, as shown in Fig. 2,
It can be seen that its feature shows themselves in that (1) discrete distribution above and below X-axis；(2) whether noise or Focus Peaks, size is all
It is symmetrical about X-axis；(3) noise of multiple time reversal signals can be built up.
For features described above, the present invention receives signal to time reversal and carries out preceding paragraph accumulation process realization noise cancellation, rises
To the effect for inhibiting noise to improve focusing performance.The noise suppressing method of TR-PPM (time reversal displacement modulation) communication,
Specifically includes the following steps:
Step 1 extracts channel impulse response
Target point emits a Gaussian pulse detectable signal in advance, and four TRM units receive respectively, and passes through CLEAN algorithm
Calculate respectively with the channel impulse response of target point；Then, time reversal mirror uses PPM pulse position modulation as transmitter；
Step 2, TR-PPM pulse position modulation
In the time reversal transmission of multidigit bitstream data, PPM modulation (Pulse Position is used
Modulation, pulse position modulation), also known as pulse-position modulation is a kind of time-modulation；PPM is that pulse position is believed according to by tune
Number variation and the modulator approach that changes, i.e., express 0 and 1 with the pulse of different time position；It modulates schematic diagram such as Fig. 3 institute
To show, symbol 0 and 1 can be expressed by the different time position of pulse, it can be seen that symbol 0 can correspond into impulse modulation code 10,
1 corresponding modulating code 01 of symbol；
Step 3, receiving end preceding paragraph preceding paragraph accumulation process
Real-time preceding paragraph accumulation process is carried out to signal is received in receiving end, specific steps are as follows:
1) spacing wireless signal obtains the electric signal of amplitude variation by antenna transmission to receiver；
2) electric signal passes through analog-to-digital conversion module, becomes the discrete digital signal after sampling, quantization by analog signal；
3) signal that feeds back 2. enters adder in the discrete signal and feedback detail inputted, after obtaining accumulation process
Signal；
4) on the one hand the signal after handling is sent into rear end and is for further processing, on the other hand 2. waited by feeding back detail
Carry out the cumulative of next signal.
Embodiment 1
Finite-Difference Time-Domain Method (FDTD) is used to carry out full-wave electromagnetic simulation study (with one in emulation to an indoor environment
A two-dimensional model replaces three-dimensional artificial, sets wall electromagnetic property for boundary), four evenly spaced dipole antennas
As time reversal mirror, target point is located at (288,244) position, near the central point in entire space, simulation architecture such as Fig. 4
It is shown；
Binary data equipped with a 5bits, bits=[11010], data are generated by random function；It is mapped to directly
Modulate the modulation code of pulse position are as follows: mod-code=[0101100110], as shown in Figure 5；Four units of time reversal mirror
Between target point overturn after channel impulse response as shown in fig. 6, with modulation code mod-code carry out pulse position modulation it
Afterwards, the signal of each unit transmitting of time reversal mirror is as shown in Figure 7: the transmitting signal of time reversal mirror each unit is imported into
It is emulated in FDTD, the signal received at target point is as shown in Figure 8, it can be seen that, the noise amplitude for receiving signal is gradually increasing；
Preceding paragraph accumulation process is carried out to signal is received, as a result as shown in Figure 9；Comparison diagram 5 and Fig. 9 receive the pulse position pair in signal
It should be in the position that modulation code 1 occurs；According to signal is received, can demodulate to obtain demodulation code by threshold value；Further according to PPM modulation
Corresponding relationship:
10→0
01→1
Demodulate initial signal.
Embodiment 2
Again by taking the signal of 20bits as an example, it is as shown in Figure 10 to be randomly generated 20 one-bit data signals, according to mapping relations, obtains
Modulation code to modulation pulse is as shown in figure 11, and the signal to be transmitted of each TRM is as shown in figure 12, imports in FDTD and is imitated
Very, the reception signal for obtaining target point is as shown in figure 13, carries out preceding paragraph and adds up, as a result as shown in figure 14, it can be seen that its result
It is consistent with 20 bit modulations；Its initial reception signal, the pulse signal of demodulation and side-lobe signal are as shown in figure 15.
By comparing the signal waveform that the unprocessed and process present invention is handled, intuitively just it can be seen that clock synchronization of the present invention
Between inverting signal time focusing performance have the effect of being significantly improved.With signal-secondary lobe ratio (SSR) for index, to measure this
Method is to the improvement of the time focusing performance of time reversal signal, according to definition, signal-secondary lobe ratio (SSR:the
Signal-to-Sidelob e Ratio) it is defined as in time reversal reception signal, the ratio of main lobe and the first secondary lobe is as follows
Shown in formula:
Wherein, xj (tpeak),xj(t'peak) respectively indicate time reversal at some receiving point receive main lobe in signal with
First side-lobes power；
Signal secondary lobe is than ssr analysis: the reception signal of 20 bit datas in calculated examples 2, obtains its signal secondary lobe ratio SSR
As shown in figure 16, it can be seen that by after preceding paragraph accumulation process, main secondary lobe ratio is significantly improved, and SSR is steady in the case where 20bit
It is scheduled on 10dB or more, and the main secondary lobe of initial signal is than then with the increase of signal bit number, gradually decreasing, or even close to 0dB,
The time focusing performance of namely signal becomes very poor.Obviously, after preceding paragraph accumulation process, multipath noise has been obtained obviously
Inhibition, it is more prominent that time reversal focuses main lobe, with better time focusing effect.After preceding paragraph accumulation process
Signal, signal-secondary lobe ratio are enhanced, and maximum improves 12.9dB, averagely raising 9.8dB.
In addition, the bit number that transmitter is once sent is more, noise level is higher, and signal-secondary lobe ratio can run down, from
And leading to the increase of the bit error rate, method proposed by the present invention can effectively inhibit the noise level of receiving end, so that same
Under the conditions of the tolerance of one bit error rate, transmitting terminal can disposably send the data of more bits, it can increase the length of each frame.
The above description is merely a specific embodiment, any feature disclosed in this specification, except non-specifically
Narration, can be replaced by other alternative features that are equivalent or have similar purpose；Disclosed all features or all sides
Method or in the process the step of, other than mutually exclusive feature and/or step, can be combined in any way.
Claims (1)
1. a kind of super broad band radio communication system noise suppressing method based on time reversal, the system uses pulse position tune
System, the described method comprises the following steps:
The pulse signal that receiver receives is obtained discrete-time signal sequence x later by analog-to-digital conversion by step 1, is set
Discrete-time signal sequence x is n total, then:
X=[x [1], x [2], x [3] ..., x [k] ..., x [n]]
Each single item x [k] in discrete-time signal sequence x, k=1,2..., n are carried out tired by step 2 with its preceding all numerical value
Add to obtain and formula y [k], it may be assumed that
To obtain discrete-time signal sequences y: y=[y [1], y [2], y [3] ..., y [k] ..., y [n]], export discrete
Timing signal sequence y carries out signal demodulation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610352168.8A CN106027166B (en) | 2016-05-25 | 2016-05-25 | A kind of super broad band radio communication system noise suppressing method based on time reversal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610352168.8A CN106027166B (en) | 2016-05-25 | 2016-05-25 | A kind of super broad band radio communication system noise suppressing method based on time reversal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106027166A CN106027166A (en) | 2016-10-12 |
| CN106027166B true CN106027166B (en) | 2019-03-05 |
Family
ID=57093864
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610352168.8A Expired - Fee Related CN106027166B (en) | 2016-05-25 | 2016-05-25 | A kind of super broad band radio communication system noise suppressing method based on time reversal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106027166B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113691474A (en) * | 2021-06-28 | 2021-11-23 | 科米纳(天津)通信科技有限公司 | Electromagnetic pulse power synthesis technology based on time reversal |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9226304B2 (en) * | 2014-03-10 | 2015-12-29 | Origin Wireless, Inc. | Time-reversal wireless paradigm for internet of things |
| CN103763225B (en) * | 2013-11-28 | 2017-01-18 | 电子信息系统复杂电磁环境效应国家重点实验室 | Signal processing device and method based on time reversal |
-
2016
- 2016-05-25 CN CN201610352168.8A patent/CN106027166B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN106027166A (en) | 2016-10-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2005518720A (en) | M-ary orthogonal coded communication method and system | |
| CN105743542B (en) | A kind of radar based on chirp waveforms-communicating integral Design of Signal method and device | |
| Kim et al. | Orthogonal pulse design in consideration of FCC and IEEE 802.15. 4a constraints | |
| CN106027166B (en) | A kind of super broad band radio communication system noise suppressing method based on time reversal | |
| Sun et al. | Novel pseudorandom phase generation in transform domain communication systems | |
| Wang et al. | A GA-based UWB pulse waveform design method | |
| CN115001917A (en) | Modulation signal generation method for radar communication integration | |
| Taki et al. | Pulse parity modulation for impulse radio UWB transmission based on non-coherent detection | |
| Askar et al. | Spectral keying/spl trade: a novel modulation scheme for UWB systems | |
| Yin et al. | Design of pulse waveform for waveform division multiple access UWB wireless communication system | |
| Wang et al. | Genetic algorithm optimization for ultra wideband impulse radio to mitigate multi-band jam interference | |
| Goyal et al. | Ultra Wideband PAM Modulation and Reception in UWB Multi Path channel Using Rake Configurations | |
| CN106385301B (en) | The method for reducing the interference of ultra-wideband impulse radio system multiband based on genetic algorithm | |
| Goyal et al. | Analyzing Pulse Position Modulation Time Hopping UWB in IEEE UWB Channel. | |
| Yao et al. | Modulation technology in ultra-wideband wireless communication | |
| Wu et al. | Multipath beamforming for UWB: channel unknown at the receiver | |
| Jemaa et al. | Chaotic time hopping based multiple access in BPSK-UWB system | |
| Chen et al. | Waveform design for UWB communication based on combined sinusoid Gaussian Pulse | |
| Kotti et al. | Asynchronous direct‐sequence ultra‐wideband communication using spatiotemporal chaotic sequences | |
| Fang et al. | Performance evaluation of RAKE receiver for ultra-wideband wireless body area network communication | |
| Shehzadi et al. | Multimode wideband waveform for software defined radio based on hybrid CPM-CDMA concept | |
| Han et al. | A novel multi-address chaotic sequence for TH-PPM-UWB system | |
| Nuño-Barrau et al. | A new time-hopping multiple access communication system simulator: Application to ultra-wideband | |
| Ou et al. | Adaptive Equalization Algorithm for 60GHz Band in 5G | |
| Craciun et al. | Multi-user interference performances for PPM-TH-UWB systems |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190305 |