CN112260976B - Broadband system anti-interference method based on F-OFDM modulation - Google Patents
Broadband system anti-interference method based on F-OFDM modulation Download PDFInfo
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- CN112260976B CN112260976B CN202011110845.8A CN202011110845A CN112260976B CN 112260976 B CN112260976 B CN 112260976B CN 202011110845 A CN202011110845 A CN 202011110845A CN 112260976 B CN112260976 B CN 112260976B
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- 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
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- 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
- H04L27/2626—Arrangements specific to the transmitter only
- H04L27/2627—Modulators
- H04L27/2634—Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
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- 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
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
- H04L27/2691—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation involving interference determination or cancellation
Abstract
The invention discloses an anti-interference method of a broadband system based on F-OFDM modulation, which comprises the following steps: 1) The initial sub-band number is 1, after the information source is coded, modulated and sub-carrier mapped, F-OFDM symbol modulation is carried out and framing is carried out to send out signals; 2) After the wireless signal is processed by a channel and FFT, interference detection is carried out on an idle frame time slot according to a designed multiframe structure, and the interference position is recorded; 3) Replanning the frequency spectrum resource according to the interference position, dividing the number of sub-bands, and calculating the corresponding sub-band filter coefficient; 4) Setting an interference region frequency domain window, and calculating EVM values inside and outside the window to serve as a basis for sub-band subcarrier spacing and data modulation mode adjustment; 5) Adjusting the sending end according to the divided sub-bands and corresponding parameters, re-mapping sub-carriers according to the number of the sub-bands, framing and sending signals; 6) The receiving end analysis process combines the data analyzed by each sub-band and enters a decoding module for decoding; by systematic simulation under the same AWGN channel, the invention not only improves the communication reliability of the broadband system in a complex channel environment, but also solves the problem of low throughput of the broadband system under the condition of the same coding efficiency.
Description
Technical Field
The invention belongs to the technical field of wireless communication, and particularly relates to an anti-interference method for a broadband system based on F-OFDM modulation.
Background
The performance of a broadband wireless communication system is seriously influenced by channel narrow-band interference and multipath frequency domain selective fading, and the system lacking the interference countermeasure even can not work normally at all.
In order to effectively resist narrowband interference and fading influence in a system and comprehensively improve the communication reliability of the system in a complex channel environment, the interference position and the interference strength are positioned through a special interference detection time slot and a detection algorithm, frequency resources planned by a data link layer are used, subcarriers of an interfered frequency band are deducted through information interaction between the link layer and a physical layer, interference frequency points are actively avoided, meanwhile, a variable subcarrier interval method in an F-OFDM (Filtered OFDM) modulation method is utilized, the subcarrier interval is reduced, the subcarrier load number is increased under the condition of not reducing the coding efficiency, and the throughput capacity of a broadband system in the data transmission process is ensured.
Disclosure of Invention
Based on the method, the invention aims to provide an anti-interference method of a broadband system based on F-OFDM modulation, and the broadband system adopting the method can still carry out normal data communication under single tone interference, multi-tone interference and broadband interference.
The invention is realized by the following technical scheme:
an anti-interference method of a broadband system based on F-OFDM modulation comprises the following steps:
step S1, initializing to set the number of sub-bands to be 1, carrying out F-OFDM symbol modulation and framing to send out signals after coding, modulating and sub-carrier mapping are carried out on an information source, and entering step S2;
step S2, after the wireless signal is processed by a channel and FFT, according to a designed multiframe structure, carrying out interference detection on an idle time slot, recording an interference position, and entering step S3;
step S3, replanning the frequency spectrum resource according to the calculated interference position, avoiding interference frequency points, dividing the number of sub-bands, calculating corresponding sub-band filter coefficients, setting a frequency domain window of an interference region, calculating EVM values inside and outside the window, serving as a basis for sub-band sub-carrier interval or data modulation mode adjustment, and entering step S4;
and S4, adjusting the transmitting end and the receiving end by utilizing the number of the divided sub-bands and corresponding calculation parameters, and combining the data blocks analyzed by the sub-bands at the receiving end to complete the anti-interference signal processing of the broadband system.
Further, the design of the multiframe structure in step S2 is as follows, where every M + N subframes in the system are one multiframe, including M data subframes and N idle subframes. The idle sub-frame is used for detecting environmental interference noise, the data sub-frame is used for system service transmission, and the sending time parameter of the data is restricted by defining a multi-frame structure so as to ensure the correct execution of sending and receiving;
further, the interference detection in step S2 includes the following steps:
step S21, executing FFT operation, and entering step S22;
step S22, calculating the signal spectrum energy and normalizing the signal spectrum energy,
wherein, in the step (A),
is the peak energy of the frequency spectrum,
step S23 is executed if the energy is the spectral average energy;
step S23, setting interference energy threshold value
And compare if
Recording the location and energy of the disturbance
) Wherein, in the process,
the RB subscript where the interference point is located,
is an interference point; if it is used
Judging whether the interference is avoided, and continuing to execute the next module;
further, the spectrum planning in step S3 includes the following steps:
step S31, setting a frequency domain window according to the interference position calculated by the interference detection,
the flow advances to step S32;
step S32, calculating the error vector magnitude value (EVM) in the frequency domain window,
wherein, in the step (A),
in order to be able to determine the amplitude error,
step S33 is entered for the transmitting end to modulate data;
step S33, judging the signal quality in the current range, if so
If yes, judging that the interference signal exists in the current window and is the subcarrier needing to be deleted, and entering step S34; if it is not
Entering a demodulation module for demodulation;
step S34, replanning the deleted sub-carriers, dividing into
Calculating the filter coefficient of each sub-band simultaneously, and entering step S35;
step S35, calculating the Error Vector Magnitude (EVM) value outside the frequency domain window,
wherein, in the step (A),
in order to be able to determine the amplitude error,
in order to modulate the data for the originating side,
for the ith subband, go to step S36;
step S36, judging that the signal quality adjustment parameter in the current range ensures that the data throughput is not reduced, if so, performing the step
Adjusting the subcarrier spacing; if it is not
Then the modulation mode of the sub-band is increased, wherein
The threshold value is a high-order modulation mode, and the current signal state is fed back to the transmitting end modulation module;
further, the adjusting of the originating end and the receiving end in step S4 includes the following steps:
step S41, according to the number of sub-bands
For the modulated data, the number of the data blocks is divided into
If the adjustment is the adjustment of the subcarrier interval, the step S42 is proceeded; if the data modulation mode is improved, entering the stepA step S43;
step S42, according to the calculated subcarrier interval of each subband, subcarrier data mapping is carried out, F-OFDM symbol modulation, framing and transmission are carried out, and the step S44 is carried out;
step S43, improving the data modulation mode of the sub-band, mapping the sub-carrier data, carrying out F-OFDM symbol modulation, framing and transmission, and entering step S44;
step S44, the receiving end demodulates and combines the data of each sub-band
And the data blocks enter a decoding module for decoding to complete the anti-interference signal processing of the system.
Drawings
Fig. 1 is a signal processing flow diagram of a transmission system of the present invention;
fig. 2, a multiframe structure of a transmission system of the present invention;
fig. 3 is a flow chart of the interference detection and spectrum planning process of the present invention;
fig. 4 shows the subband division process of the wideband system of the present invention.
Detailed Description
To make the objects and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings and examples.
Fig. 1 is a flow chart of signal processing of a transmission system according to the present invention, and the specific method includes the following steps:
step S11, initializing and setting the number of sub-bands
After the information source is coded, modulated and sub-carrier mapped, F-OFDM symbol modulation is carried out and framing is carried out to send out signals, and the step S12 is carried out;
step S12, after the wireless signal is subjected to channel and FFT processing, according to a designed multiframe structure, as shown in fig. 2, M =99, n =1, t =1s, performing interference detection on an idle slot, recording an interference position, and proceeding to step S13;
step S13, replanning the frequency spectrum resource according to the calculated interference position, avoiding interference frequency points, dividing the number of sub-bands, calculating corresponding sub-band filter coefficients, setting a frequency domain window of an interference area, calculating EVM values inside and outside the window, serving as a basis for sub-band sub-carrier interval or data modulation mode adjustment, and entering step S14;
and S14, adjusting the transmitting end and the receiving end by utilizing the number of the divided sub-bands and corresponding calculation parameters, and combining the sub-band analyzed data blocks at the receiving end to complete the anti-interference signal processing of the broadband system.
Fig. 3 is a flowchart of interference detection and spectrum planning processing of the present invention, and the specific method includes the following steps:
step S31, carrying out interference detection on the received signal to obtain an RB subscript where an interference position is located, and entering step S32;
step S32, setting a frequency domain window, nRB =2,
and calculating EVM value in the frequency domain window, and setting demodulation threshold value
The flow proceeds to step S33;
step S33, if the calculated EVM is greater than
Deleting the current frequency point subcarrier and entering step S34; otherwise, directly entering a demodulation module for demodulation;
step S34, replanning the spectrum, dividing into 2 sub-bands as shown in fig. 4, calculating the filter coefficient of each sub-band, and proceeding to step S35;
step S35, calculating the EVM value outside the frequency domain window, and setting the threshold value of the high-order modulation mode
Step S36 is entered;
step S36, if greater than
If so, adjusting the subcarrier interval and carrying out F-OFDM symbol modulation; if less than
Increasing the modulation mode of the sub-band and carrying out F-OFDM symbol modulation; and simultaneously, the current signal state is fed back to the transmitting end modulation module to complete the signal processing process.
In summary, the above description is only a preferred example of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. An anti-interference method of broadband system based on F-OFDM modulation is characterized in that the number of the initial sub-bands of a system transmitting end is set to be 1, data sub-carrier mapping is carried out, and framing is carried out to send out signals; the receiving end carries out interference detection on an idle frame time slot and records the interference position in the process of processing the received multi-frame data; re-planning the frequency spectrum resources according to the interference position, avoiding interference frequency points, dividing the number of sub-bands, and calculating corresponding sub-band filter coefficients; setting an interference region frequency domain window, and calculating EVM values inside and outside the window to serve as a basis for sub-band subcarrier spacing and data modulation mode adjustment; adjusting the transmitting end by utilizing the number of the divided sub-bands and corresponding calculation parameters, blocking the modulation data according to the number of the sub-bands, respectively carrying out sub-carrier mapping on different sub-bands and framing to send signals; analyzing the data at the receiving end, combining the analyzed data of each sub-band, and entering a decoding module for decoding;
the multiframe data is that every M + N subframes in the system are a multiframe, and the multiframe comprises M data subframes and N idle subframes; the idle sub-frame is used for detecting environmental interference noise, the data sub-frame is used for system service transmission, and the sending time parameter of the data is restricted by defining a multi-frame structure so as to ensure the correct execution of sending and receiving;
the spectral planning and sub-band segmentation, the specific implementation steps include,
4.1 setting a frequency domain window according to the interference position calculated by the interference detection,
W＝[RB index -nRB：RB index +nRB]entering step 4.2;
4.2 calculate the Error Vector Magnitude (EVM) value in the frequency domain window,
4.3 judging the signal quality in the current range, if
Judging that the interference signal exists in the current window, and entering the step 4.4 if the interference signal is a subcarrier needing to be deleted; if it is not
Entering a demodulation module for demodulation;
4.4 replanning the deleted sub-carriers, dividing into N sub The sub-bands are calculated, and the filtering coefficient of each sub-band is calculated at the same time, and the step 4.5 is carried out;
4.5 calculate the Error Vector Magnitude (EVM) outside the frequency domain window,
4.6 judging the signal quality adjusting parameter in the current range to ensure that the data throughput is not reduced, if so, judging whether the signal quality adjusting parameter in the current range is in the same range as the signal quality adjusting parameter in the current range or not
Adjusting the subcarrier spacing; if it is not
The modulation scheme of the sub-band is increased, wherein
And the current signal state is fed back to the transmitting end modulation module at the same time when the current signal state is the threshold value of the high-order modulation mode.
2. The method of claim 1, wherein the interference detection comprises the following steps,
3.1 executing FFT operation, and entering step 3.2;
3.2 calculating the signal spectrum energy and normalizing the signal spectrum energy,
E u ＝E peak /E mean wherein, E peak Is the peak energy of the spectrum, E mean Entering step 3.3 for the spectrum mean energy;
3.3 setting the interference energy threshold, E TH And compare if E u ＞E TH Recording the location and energy of the disturbance
Wherein RB index RB subscript, I, where interference point is located pos Is an interference point; if E u ≤E TH And if no interference exists, continuing to execute the next module.
3. The method of claim 1, wherein the transmitter is adapted to implement the steps of,
5.1 the originating received signal state and processing, including the number of sub-bands N sub Adjusting the subcarrier spacing delta f or increasing the modulation mode mcs, and blocking the modulation data, wherein the number of the data blocks is N sub If the adjustment is the subcarrier interval adjustment, the step 5.2 is carried out; if it is a data modulation modeIncreasing, and entering step 5.3;
5.2, mapping the sub-carrier data according to the calculated sub-carrier interval of each sub-band, wherein the sub-band bandwidth is reduced, the modulation mode is unchanged, and the number of the sub-carriers is increased so as to ensure that the data transmission rate is unchanged, carrying out F-OFDM symbol modulation, framing and transmission, and entering step 5.4;
5.3, improving the data modulation mode of the sub-band, mapping the sub-carrier data, reducing the bandwidth, keeping the number of the sub-carriers unchanged, improving the modulation mode to ensure that the data transmission rate is unchanged, carrying out F-OFDM symbol modulation, framing and transmission, and entering the step 5.4;
5.4 the receiving end demodulates the data of each sub-band and combines N sub And the data blocks enter a decoding module for decoding to complete the anti-interference signal processing of the system.
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| CN114726700B (en) * | 2022-04-22 | 2024-02-06 | 哈尔滨工业大学 | Self-adaptive anti-interference synchronization method of multi-carrier communication system facing interference scene |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102427441A (en) * | 2011-12-09 | 2012-04-25 | 杭州宏睿通信技术有限公司 | Anti-interference method applied to time-division OFDM (Orthogonal Frequency Division Multiplexing) system |
| CN103036836A (en) * | 2011-10-10 | 2013-04-10 | 京信通信系统（中国）有限公司 | Orthogonal frequency division multiple access (OFDMA) system signal processing method and device |
| CN103095633A (en) * | 2011-11-04 | 2013-05-08 | 上海瀚讯无线技术有限公司 | Method resisting narrow-band interference in orthogonal frequency division multiplexing (OFDM) communication system |
| CN103581092A (en) * | 2012-08-08 | 2014-02-12 | 中国移动通信集团公司 | Method and device for reducing out-of-band interference of cognitive radio |
| JP2015027069A (en) * | 2013-07-29 | 2015-02-05 | エフシーアイ インク | Ofdm reception signal processing method and ofdm receiver using the same |
| WO2016039668A2 (en) * | 2014-09-08 | 2016-03-17 | Telefonaktiebolaget L M Ericsson (Publ) | Interference mitigation |
| CN110677186A (en) * | 2019-08-22 | 2020-01-10 | 西安空间无线电技术研究所 | Satellite communication anti-interference method based on carrier splitting |
| CN111698185A (en) * | 2020-06-16 | 2020-09-22 | Oppo广东移动通信有限公司 | Carrier interference elimination method and device, electronic equipment and storage medium |
| CN113794664A (en) * | 2021-09-10 | 2021-12-14 | 北京环佳通信技术有限公司 | Anti-interference method based on subcarrier deduction |
-
2020
- 2020-10-16 CN CN202011110845.8A patent/CN112260976B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103036836A (en) * | 2011-10-10 | 2013-04-10 | 京信通信系统（中国）有限公司 | Orthogonal frequency division multiple access (OFDMA) system signal processing method and device |
| CN103095633A (en) * | 2011-11-04 | 2013-05-08 | 上海瀚讯无线技术有限公司 | Method resisting narrow-band interference in orthogonal frequency division multiplexing (OFDM) communication system |
| CN102427441A (en) * | 2011-12-09 | 2012-04-25 | 杭州宏睿通信技术有限公司 | Anti-interference method applied to time-division OFDM (Orthogonal Frequency Division Multiplexing) system |
| CN103581092A (en) * | 2012-08-08 | 2014-02-12 | 中国移动通信集团公司 | Method and device for reducing out-of-band interference of cognitive radio |
| JP2015027069A (en) * | 2013-07-29 | 2015-02-05 | エフシーアイ インク | Ofdm reception signal processing method and ofdm receiver using the same |
| WO2016039668A2 (en) * | 2014-09-08 | 2016-03-17 | Telefonaktiebolaget L M Ericsson (Publ) | Interference mitigation |
| CN110677186A (en) * | 2019-08-22 | 2020-01-10 | 西安空间无线电技术研究所 | Satellite communication anti-interference method based on carrier splitting |
| CN111698185A (en) * | 2020-06-16 | 2020-09-22 | Oppo广东移动通信有限公司 | Carrier interference elimination method and device, electronic equipment and storage medium |
| CN113794664A (en) * | 2021-09-10 | 2021-12-14 | 北京环佳通信技术有限公司 | Anti-interference method based on subcarrier deduction |
Non-Patent Citations (3)
| Title |
|---|
| A Reliable OFDM-Based MMW Mobile Fronthaul With DSP-Aided Sub-Band Spreading and Time-Confined Windowing;You-Wei Chen;《Journal of Lightwave Technology》;20190425;第37卷(第13期);全文 * |
| Fractionally Spaced Frequency-Domain MMSE Receiver for OFDM Systems;Qinghua Shi;《IEEE Transactions on Vehicular Technology》;20100927;第59卷(第9期);全文 * |
| OFDM系统干扰消除方法研究;马涛;《中国优秀硕士学位论文全文数据库 (信息科技辑)》;20200615;全文 * |
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