CN106453171A - Self-interference elimination method of co-frequency co-time full duplex system - Google Patents
Self-interference elimination method of co-frequency co-time full duplex system Download PDFInfo
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- CN106453171A CN106453171A CN201510477735.8A CN201510477735A CN106453171A CN 106453171 A CN106453171 A CN 106453171A CN 201510477735 A CN201510477735 A CN 201510477735A CN 106453171 A CN106453171 A CN 106453171A
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- signal
- frequency
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- full duplex
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- 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
- H04L25/06—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
- H04L25/061—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
- H04B1/1018—Means associated with receiver for limiting or suppressing noise or interference noise filters connected between the power supply and the receiver
-
- 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
- H04L25/08—Modifications for reducing interference; Modifications for reducing effects due to line faults ; Receiver end arrangements for detecting or overcoming line faults
Abstract
The invention provides a self-interference elimination method of a co-frequency co-time full duplex system. The method comprises the following steps of introducing an analog reference signal from a transmitting end, performing dividing operation on a received signal and the reference signal for converting a self-interference signal to a DC signal and a frequency doubling component, and changing an objective signal to a low-frequency signal and a frequency doubling component; transmitting the DC signal and the low-frequency signal to a low-pass filter and a DC blocking filter, filtering the self-interference signal, and keeping the low-frequency signal (objective signal); and before demodulation, multiplying the low-frequency signal with a transmitting end baseband reference signal for recovering the waveform of the objective signal. The self-interference elimination method of the co-frequency co-time full duplex system has advantages of finishing self-interference elimination before digital-to-analog conversion, eliminating effect of a channel characteristic to interference elimination, reducing quantization noise and reducing technical complexity in self-interference elimination.
Description
Technical field
The present invention relates to frequency full duplex interference cancellation techniques simultaneously, belonging to wireless communication field.
Background technology
In traditional half duplex techniques, uplink and downlink signal relies on orthogonal frequency domain or time-domain resource to be distinguish between, spectrum efficiency
Relatively low.With frequency, full duplex technology, as the key technology improving spectrum efficiency, realizes two sides on same physical channel simultaneously
To signal transmission, make each communication node that uplink and downlink signal to be received and dispatched on identical frequency range simultaneously, obtain the extensive of industry
Concern.Compared with traditional half duplex techniques, with frequency, full duplex technology can make full use of frequency spectrum resource simultaneously, realizes bigger
Throughput capacity, has become as one of key technology of 5G communication.
In full duplex system, due to same transceiver transmitting antenna and reception antenna apart from relative close, by transmitting sky
The self-interference signal power ratio target signal power that line is leaked to reception antenna is much larger, and how effectively to eliminate self-interference becomes same
The key of frequency full duplex technology simultaneously.According to the difference in receiver link position for the self-interference cancellation module, self-interference eliminates and is divided into
Antenna interference suppression, radio frequency eliminate and digital baseband eliminates etc..Antenna interference cancellation techniques are to reduce full duplex by Antenna Design
On node, the electromagnetic coupled between transmitting antenna and reception antenna is reducing self-interference signal power；And radio frequency is eliminated and is launched using local
The radiofrequency signal of machine, being adjusted to, opposite in phase identical with receipt signal amplitude, being merged with radio frequency receiving signal thus offsetting
Self-interference；Digital baseband interference elimination method is to eliminate residual self-interference by digital signal processing algorithm after digital sample.
Existing with frequency simultaneously full duplex receiver structure as shown in figure 1, receipt signal comprises target and self-interference signal, they
Sequentially pass through antenna isolation, radio frequency elimination, down coversion, ADC (Analog-to-Digital Converter, analog-digital converter),
The module such as base band elimination and demodulation.Existing interference cancellation techniques have some limitations, and are mainly manifested in following aspect：
First, Radio frequency interference cancellation module needs to adjust the amplitude of reference signal, phase place according to channel response and residual interference,
The time-varying characteristics of wireless channel lead to Radio frequency interference to eliminate the necessary self-adaptative adjustment parameter of circuit with track channel change, and self adaptation is calculated
The implementation complexity of method is higher；
Secondly as the multipath effect of wireless channel, interference signal is the result of multipath interference signal superposition, and existing radio frequency is done
Disturb removing method and can only eliminate the interference of main footpath, and the interference in remaining path cannot be eliminated, interference eradicating efficacy is limited；
3rd, through Radio frequency interference eliminate after signal be converted to digital signal, due to the resolution of ADC is low or dynamic range not
Enough, ADC cannot accurately obtain the useful component in receipt signal, leads to useful signal to be lost in quantizing process, and then affects
The accuracy of base band data demodulation；
Finally, base band interference eliminates the need for corresponding signal processing algorithm estimation interference channel, technical sophistication, realizes difficulty big.
Content of the invention
Frequently receipt signal y of full duplex receiver is expressed as simultaneously together：
Wherein, PT、hTAnd STRepresent the transmission power of echo signal, the analogue signal of channel response and destination node transmitting, P respectivelyI、
hIAnd SIRepresent the transmission power of self-interference signal, the analogue signal of channel response and the transmitting of self-interference node respectively, n makes an uproar for reception
Sound.With frequency, full duplex receiver will eliminate self-interference signal the receipt signal shown in from formula (1) simultaneously, demodulate echo signal.
For reducing the technical sophistication degree that full duplex self-interference eliminates, reduce ADC quantizing noise, eliminate time varying channel and interference is eliminated
Impact, the present invention provide a kind of with frequency full duplex system self-interference removing method simultaneously, the method by three below step Lai
Complete：
(1). interference signal direct current
The intermediate frequency of transmitting terminal or radio frequency analog signal are sent to receiver, this signal is expressed as reference signal SRef_1, and SRef_1=SI.
The receipt signal of receiver and reference signal do division arithmetic, i.e. y/SRef_1, the signal spectrum after computing is as shown in Figure 2.Due to
SRef_1It is sine wave analogue signal with y, after division arithmetic, self-interference signal is changed into direct current signal and two harmonics, target
Signal is changed into low frequency signal and two harmonics.
(2). interference signal filters
Step (1) gained signal passes through low pass filter and stopping direct current wave filter, filters two harmonics and direct current signal, retains
Low frequency signal (echo signal).Signal spectrum with reference to shown in Fig. 2, through this step, self-interference signal is filtered out, and target is believed
Number be retained.
(3). echo signal wave recovery
Transmitting terminal base-band analog signal or digital signal are sent to receiver, this signal is expressed as reference signal SRef_2.In demodulation
Before, by the low frequency (echo signal) and reference signal S that retainRef_2It is multiplied to recover echo signal waveform.Due to step (2)
The amplitude of output signal, phase place are interfered the modulation of signal, and through this step, echo signal waveform is recovered, with after an action of the bowels
Continuous signal processing module demodulating information bit.
Beneficial effects of the present invention：
While the present invention provides, self-interference signal is converted into direct current letter by division arithmetic by co-channel full duplex self-interference removing method
Number, and direct current is filtered by stopping direct current wave filter.The method technical sophistication degree is low, and the characteristic of channel is only had with the intensity of direct current signal
Close, do not affect to disturb eradicating efficacy, effectively overcome the impact that channel multi-path and time-varying characteristics eliminate to interference.Additionally, this
Invent proposed method and be directed to analogue signal realization interference elimination it is not necessary to estimate interference channel in numeric field, technical difficulty drops
Low.Receipt signal eliminated self-interference signal before ADC, reduced ADC quantizing noise, improve the bit error rate of system
Performance.
Brief description
The interference of Fig. 1 existing full duplex receiver eliminates structure chart；
Fig. 2 receipt signal and reference signal be divided by after signal spectrum schematic diagram；
Fig. 3 embodiment of the present invention is with the transmitter architecture schematic diagram of frequency full duplex system simultaneously；
Receiver interference in Fig. 4 embodiment of the present invention eliminates structure chart.
Specific embodiment
Below in conjunction with the accompanying drawings and specific embodiment, the present invention is described in further detail.
With frequency full duplex system simultaneously transmitter architecture as shown in figure 3, bit sequence is modulated, molding filtration, numerically become
Frequency and DAC (Digital-to-Analog Converter, digital to analog converter) form analog intermediate frequency signal, through up-converting to radio frequency
Signal, then launched by antenna.Intermediate frequency and radiofrequency signal are respectively by SmfAnd SrfRepresent.
In the receiving terminal of full duplex node, reception antenna has self-interference isolating power, and the radiofrequency signal that it receives comprises to come spontaneous
Penetrate the self-interference signal at end, from echo signal and the noise of destination node.Receipt signal completes self-interference in analog domain and eliminates,
Then the demodulation of information bit is completed by modules such as ADC, channel equalization, matched filterings.
Consider two full-duplex communication nodes carry out point-to-point communication, communication node identical frequency and carry out on the time transmitting and
Receive.Receiver structure in the present invention is as shown in figure 4, intermediate frequency (or radio frequency) signal of transmitter generation and baseband signal are passed
Deliver to receiver as reference signal, be designated as S respectivelyRef_1And SRef_2, transmitter directly generates 1/SRef_1, through multiplier with
Receipt signal is multiplied, and self-interference signal is changed into direct current signal and two harmonics, and echo signal is changed into low frequency signal and two times of frequency divisions
Amount, signal sequentially passes through low pass filter and stopping direct current wave filter is changed into low frequency signal (echo signal).Subsequently, signal is multiplied by base
Band reference signal SRef_2, recover amplitude and the phase place of echo signal, the echo signal of recovery carries out channel equalization, coupling filter successively
Ripple and symbol demodulation etc..
If SRef_1For transmitter intermediate-freuqncy signal Smf, the receipt signal of reception antenna carries out down-converting to intermediate-freuqncy signal, complete in intermediate frequency
Become to sequentially pass through interference signal direct current, interference signal filters to eliminate self-interference with echo signal wave recovery three step, then passes through
The module demodulating information bit such as ADC, Digital Down Convert, matched filtering.If SRef_1For transmitter RF signal Srf, receive letter
Number frequency spectrum is changed into low frequency, because without the down conversion module shown in Fig. 4 dotted line.
During recovering echo signal waveform, multiplying completes in signal mode near-field or numeric field, corresponding SRef_2Respectively
For transmitting terminal base-band analog signal or baseband digital signal.
When transmitting terminal adopts MPSK to modulate, pass band near flat, launch end signal SIFor constant envelope signal.
Reference signal is generated by transmitter, the signal being formed through conjugater transformation is expressed as SRef_1 *, by receipt signal and SRef_1 *Mutually it is multiplied
Become the direct current of interference signal, reduce further complicated technology realization degree.
If additionally, the carrier signal of receiver I, Q road quadrature frequency conversion can be with the carrier wave on I, Q road receiving interference signal
Signal phase is identical, then carry out signal processing for I, Q road respectively in base band.
The interference signal of transmitting can be information symbol can also be frequency pilot sign.
Above with example, the present invention will be further described.It should be noted that the purpose announcing example is to help further
Understand the present invention, but it will be appreciated by those skilled in the art that：In the scope without departing from the present invention and claims
Interior, various substitutions and modifications are all possible.Therefore, the present invention should not be limited to example disclosure of that, application claims
The scope of protection is defined by the scope that claims define.
Claims (8)
1. a kind of same frequency full duplex system self-interference removing method simultaneously, comprises the steps：
1) interference signal direct current：Introduce analog from transmitting terminal, the receipt signal of receiver is removed with this reference signal
Method computing, makes self-interference signal be changed into direct current signal and two harmonics, echo signal is changed into low frequency signal and two harmonics；
2) interference signal filters：Step 1) gained signal passes sequentially through low pass filter and stopping direct current wave filter, filters two frequencys multiplication
Component and direct current signal, retain low frequency signal；
3) echo signal wave recovery：Before echo signal demodulation, above-mentioned low frequency signal is multiplied by transmitting terminal baseband reference signal.
2. as claimed in claim 1 with frequency simultaneously full duplex system self-interference removing method it is characterised in that step 1) in
Intermediate frequency or radio frequency analog signal that analog generates for transmitter.
3. as claimed in claim 1 with frequency simultaneously full duplex system self-interference removing method it is characterised in that step 3) in
Transmitting terminal baseband reference signal be transmitting terminal base-band analog signal or baseband digital signal.
4. as claimed in claim 2 with frequency simultaneously full duplex system self-interference removing method it is characterised in that transmitter generate
As reference signal, receipt signal carries out down-converting to intermediate-freuqncy signal intermediate-freuqncy signal first.
5. as claimed in claim 1 with frequency simultaneously full duplex system self-interference removing method it is characterised in that directly by launching
Machine generate analogue signal form reciprocal, by step 1) in division be converted into signal multiplication.
6. as claimed in claim 1 with frequency simultaneously full duplex system self-interference removing method it is characterised in that transmitting terminal adopt
MPSK modulates, step 1) in the analogue signal that generated by transmitter forms reference signal through conjugater transformation, then believe receiving
Number it is multiplied with this reference signal.
7. as claimed in claim 1 with frequency simultaneously full duplex system self-interference removing method it is characterised in that make receiver I,
The carrier signal of Q road quadrature frequency conversion is identical with the carrier signal phase on I, Q road receiving interference signal, is respectively directed in base band
I, Q road carries out step 1) 3) shown in self-interference eliminate.
8. as claimed in claim 1 with frequency simultaneously full duplex system self-interference removing method it is characterised in that transmitting end signal
It is information symbol or frequency pilot sign.
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| CN201510477735.8A CN106453171A (en) | 2015-08-06 | 2015-08-06 | Self-interference elimination method of co-frequency co-time full duplex system |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110912582A (en) * | 2018-09-17 | 2020-03-24 | 西安中兴新软件有限责任公司 | Method, equipment and storage medium for eliminating simultaneous same-frequency full-duplex self-interference signal |
| CN111107027A (en) * | 2019-12-05 | 2020-05-05 | 北京航空航天大学杭州创新研究院 | High-performance same-frequency full-duplex self-interference cancellation method |
| CN112821903A (en) * | 2020-12-30 | 2021-05-18 | 天津师范大学 | Simultaneous same-frequency full-duplex self-adaptive digital self-interference elimination time slot selection method |
| CN112910885A (en) * | 2021-01-29 | 2021-06-04 | 湖北民族大学 | Secure communication system and method based on Wheatstone bridge balance method |
| CN112970232A (en) * | 2018-11-08 | 2021-06-15 | 华为技术有限公司 | Method, equipment and system for eliminating interference |
| CN113169762A (en) * | 2021-04-19 | 2021-07-23 | 华为技术有限公司 | Communication device and method |
| CN115473560A (en) * | 2022-08-29 | 2022-12-13 | 西安电子科技大学 | Unmanned aerial vehicle communication radar integrated full-duplex relay transmission system, relay method and node |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338172A (en) * | 2013-07-24 | 2013-10-02 | 电子科技大学 | Simultaneous common-frequency full duplex self-interference offset method in multi-path environment |
| CN103634022A (en) * | 2013-12-09 | 2014-03-12 | 电子科技大学 | Full-duplex transceiver in flat fading environment and method for canceling self-interference |
| CN103957182A (en) * | 2014-05-21 | 2014-07-30 | 苏州东奇信息科技股份有限公司 | Co-channel full-duplex system based on MPPSK modulation |
-
2015
- 2015-08-06 CN CN201510477735.8A patent/CN106453171A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338172A (en) * | 2013-07-24 | 2013-10-02 | 电子科技大学 | Simultaneous common-frequency full duplex self-interference offset method in multi-path environment |
| CN103634022A (en) * | 2013-12-09 | 2014-03-12 | 电子科技大学 | Full-duplex transceiver in flat fading environment and method for canceling self-interference |
| CN103957182A (en) * | 2014-05-21 | 2014-07-30 | 苏州东奇信息科技股份有限公司 | Co-channel full-duplex system based on MPPSK modulation |
Non-Patent Citations (1)
| Title |
|---|
| JUN WANG，HONGZHI ZHAO，YOUXI TANG: "A RF Adaptive Least Mean Square Algorithm for self-interference Cancellation in Co-frequency Co-time Full Duplex Systems", 《IEEE ICC 2014 - WIRELESS COMMUNICATIONS SYMPOSIUM》 * |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110912582B (en) * | 2018-09-17 | 2023-04-07 | 西安中兴新软件有限责任公司 | Method, equipment and storage medium for eliminating simultaneous same-frequency full-duplex self-interference signal |
| CN110912582A (en) * | 2018-09-17 | 2020-03-24 | 西安中兴新软件有限责任公司 | Method, equipment and storage medium for eliminating simultaneous same-frequency full-duplex self-interference signal |
| CN112970232A (en) * | 2018-11-08 | 2021-06-15 | 华为技术有限公司 | Method, equipment and system for eliminating interference |
| US11895522B2 (en) | 2018-11-08 | 2024-02-06 | Huawei Technologies Co., Ltd. | Interference cancellation method, device, and system |
| CN112970232B (en) * | 2018-11-08 | 2022-07-12 | 华为技术有限公司 | Method, equipment and system for eliminating interference |
| CN111107027A (en) * | 2019-12-05 | 2020-05-05 | 北京航空航天大学杭州创新研究院 | High-performance same-frequency full-duplex self-interference cancellation method |
| CN111107027B (en) * | 2019-12-05 | 2022-06-28 | 北京航空航天大学杭州创新研究院 | High-performance same-frequency full-duplex self-interference cancellation method |
| CN112821903A (en) * | 2020-12-30 | 2021-05-18 | 天津师范大学 | Simultaneous same-frequency full-duplex self-adaptive digital self-interference elimination time slot selection method |
| CN112821903B (en) * | 2020-12-30 | 2022-09-16 | 天津师范大学 | Simultaneous same-frequency full-duplex self-adaptive digital self-interference elimination time slot selection method |
| CN112910885A (en) * | 2021-01-29 | 2021-06-04 | 湖北民族大学 | Secure communication system and method based on Wheatstone bridge balance method |
| CN113169762B (en) * | 2021-04-19 | 2023-03-31 | 华为技术有限公司 | Communication device and method |
| CN113169762A (en) * | 2021-04-19 | 2021-07-23 | 华为技术有限公司 | Communication device and method |
| CN115473560A (en) * | 2022-08-29 | 2022-12-13 | 西安电子科技大学 | Unmanned aerial vehicle communication radar integrated full-duplex relay transmission system, relay method and node |
| CN115473560B (en) * | 2022-08-29 | 2024-02-06 | 西安电子科技大学 | Unmanned plane communication radar integrated full duplex relay transmission system, relay method and node |
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