CN102970688B - A kind of frame signal detection method for WLAN devices and device - Google Patents
A kind of frame signal detection method for WLAN devices and device Download PDFInfo
- Publication number
- CN102970688B CN102970688B CN201110255695.4A CN201110255695A CN102970688B CN 102970688 B CN102970688 B CN 102970688B CN 201110255695 A CN201110255695 A CN 201110255695A CN 102970688 B CN102970688 B CN 102970688B
- Authority
- CN
- China
- Prior art keywords
- sequence
- correlation
- added
- frame signal
- postponed
- 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.)
- Active
Links
Abstract
The invention provides a kind of in WLAN devices to IEEE? 802.11g? 802.11a? 802.11n frame signal carries out the method and apparatus detected.The method is according to 20MHz bandwidth and 40MHz bandwidth two kinds of situations, and by Received signal strength, local sequence or the local sequence of 40M carry out related operation with 20M respectively, obtain basic correlated series.Different Late phase add operations is carried out for basic correlated series, and compares from different setting thresholds.As long as there is certain correlation to be greater than corresponding threshold value, then complete the testing process of frame signal.
Description
Technical field:
For 802.11g/802.11a/802.11n frame signal detection method and the device of WLAN devices, it belongs to digital communication technology field, relates to the method and apparatus of achieve frame input in wireless LAN communication process.
Background technology:
In wireless LAN communication process, transmitter sends packet discontinuously according to specific IEEE802.11b, 802.11g, 802.11a, 802.11n frame format.After receiver detects specific frame format, start AGC adjustment, synchronously, demodulation, the subsequent processes such as decoding.
Because wlan system does not have close-loop power control mechanism.Therefore each transmitter is all with close fixing power transmission signal.And the signal energy scope of the burst frame that receiver antenna termination receives can from-95dBm to-10dBm not etc.For the weak signal being less than-80dBm, due to factor impacts such as the noise jamming that radio frequency is introduced, the method adopting energy measuring to carry out frame signal detection becomes very unreliable.Therefore need to adopt correlation technique to detect.The related detecting method of traditional IEEE802.11g, IEEE802.11a preserves one section of correlated series in this locality exactly, carries out computing cross-correlation with the baseband signal of input.When detecting that correlation is greater than setting threshold, namely judge to receive corresponding frame.
When standard evolves to IEEE802.11n standard, the frame format of transmitting changes a lot.IEEE802.11n standard supports single antenna stream frame format, double antenna stream frame format, triantennary stream frame format, and four antenna stream frame formats.For frames more than two antennas, the signal demand that standard gauge fixes in different transmit antennas carries out cyclic shift diversity operation, causes the short training sequence that different transmit antennas is launched to have different cyclic shifts.It is below the cyclic shift list about stream during different sky in IEEE802.11n agreement.The cyclic shift of Non-HT form is used for the frame signal of MixedFormat form.The cyclic shift of HT form is used for the frame signal of Greenfield form.
IEEE802.11n protocol tables non-HT form cyclic shift
IEEE802.11n protocol tables HT form cyclic shift
Because 11n agreement adds the frame (comprising MixedFormat and GreenfieldFormat) of a variety of different cyclic shift, basic related detecting method performance is caused greatly to decline.Simultaneously because WLAN devices works in indoor environment mostly.Environment such as Complex Channel such as non line of sight (NLOS) multipath channel and indoor multipath channel etc. will affect original coherent detection performance.These all cause 11n equipment to adopt basic coherent detection effect undesirable.
Have one intuitively scheme be, for each frame format of IEEE802.11n, design a local sequence, adopt cross-correlation method, carry out threshold test.Certain frame detection perform improvement can be obtained although do like this, there are two shortcomings.First this method needs to use multiple cross-correlator.And the logical circuit scale of correlator is large, adopt this method Logical cost too large.Second this method improves not remarkable for detection perform under multiple antennas.When launch multiple link attenuation and link additive phase inconsistent time, the Detection results of the method will decline.
Accompanying drawing 3 represents the STBC signal output sequence through local sequence cross-correlation after of two antenna STBC signals at single spatial flow two antenna transmission.Can see that sequence of correlation values is all lower than 80, is not easy to detect frame.
Summary of the invention:
In order to solve for 11n many kinds of frame formats, under multipath channel case, the problem of frame signal detection difficult, the present invention adopts a kind of correlated series to postpone the method be added.Power is detected as by the frame signal under the method increasing various frame format and under multi-path environment.
The invention provides a kind of in WLAN devices to the method and apparatus that IEEE802.11g802.11a802.11n frame signal detects, as shown in Figure 4, frame signal under improve various frame format and under multi-path environment is detected as power, and the method comprises the following steps:
(1) Received signal strength and local sequence are carried out computing cross-correlation, obtain correlated series 1;
(2) be added after correlated series 1 being postponed 0.8us, formation sequence 2;
(3) be added after sequence 2 being postponed 0.4us, formation sequence 3; Be added after sequence 2 is postponed 0.2us, formation sequence 4;
(4) be added after sequence 3 being postponed 0.2us, formation sequence 5;
(5) be added after sequence 4 being postponed 0.1us, formation sequence 6;
(6) be added after sequence 5 being postponed 0.6us, formation sequence 7;
(7) be added after sequence 2 being postponed 0.10us, then be added after postponing 0.05us, then be added after postponing 0.15us, formation sequence 8;
(8) for the frame signal of 802.11g, 802.11a and 802.11n single transmit antenna stream, whether the correlation detecting sequence 2 is greater than setting threshold; Whether the correlation that the frame signal for two transmitting antenna stream MixedFormat patterns detects sequence 3 is greater than setting threshold; For the frame signal of two transmitting antenna stream Greenfield patterns, whether the correlation detecting sequence 4 is greater than setting threshold; For the frame signal of three transmitting antenna stream MixedFormat patterns, whether the correlation detecting sequence 5 is greater than setting threshold; For the frame signal of three transmitting antenna stream Greenfield patterns, whether the correlation detecting sequence 6 is greater than setting threshold; For the frame signal of four antenna stream Greenfield patterns, whether the correlation detecting sequence 8 is greater than setting threshold;
(9) as long as there is certain correlation to be greater than corresponding setting threshold in above-mentioned sequence, then the testing process of frame signal is completed.
Wherein, correlation is greater than threshold value and refers to that the absolute value of the correlation of correlated series is greater than detection threshold.For different correlated serieses, adopt different detection thresholds.
The invention provides a kind of in WLAN devices to the device that IEEE802.11g802.11a802.11n frame signal detects, this device has following modules: computing cross-correlation device, postpone adder, threshold comparator.The effect of computing cross-correlation device the baseband signal of reception and local sequence is carried out computing cross-correlation obtain sequence 1.The effect postponing adder is added with this sequence after list entries is postponed the given time again.Postpone to be added after correlated series 1 is postponed 0.8us by adder, formation sequence 2; Be added after sequence 2 is postponed 0.4us, formation sequence 3; Be added after sequence 2 is postponed 0.2us, formation sequence 4; Be added after sequence 3 is postponed 0.2us, formation sequence 5; Be added after sequence 4 is postponed 0.1us, formation sequence 6; Be added after sequence 5 is postponed 0.6us, formation sequence 7; Be added after sequence 2 is postponed 0.10us, then be added after postponing 0.05us, then be added after postponing 0.15us, formation sequence 8.The effect of threshold comparator is, list entries and given threshold value is compared.For the frame signal of 802.11g, 802.11a and 802.11n single transmit antenna stream, whether the correlation that described threshold comparator detects sequence 2 is greater than setting threshold; For two transmitting antenna stream MixedFormat patterns frame signal described in threshold comparator detect the correlation of sequence 3 and whether be greater than setting threshold; For the frame signal of two transmitting antenna stream Greenfield patterns, whether the correlation that described threshold comparator detects sequence 4 is greater than setting threshold; For the frame signal of three transmitting antenna stream MixedFormat patterns, whether the correlation that described threshold comparator detects sequence 5 is greater than setting threshold; For the frame signal of three transmitting antenna stream Greenfield patterns, whether the correlation that described threshold comparator detects sequence 6 is greater than setting threshold; For the frame signal of four antenna stream Greenfield patterns, whether the correlation that described threshold comparator detects sequence 8 is greater than setting threshold.The value in moment as a certain in infructescence is greater than setting threshold and then exports index signal.Adopt the frame signal checkout gear of said method, have logical circuit small scale, sensitive to Testing of Feeble Signals, the advantage sensitive to input under multi-path channel environment, improves and detects accuracy in the frame signal of various complex condition.
Accompanying drawing illustrates:
Fig. 1 is IEEE802.11n standard Mixedformat and Greenfieldformat frame format structure.
Fig. 2 is the output sequence of IEEE802.11a frame preamble after local sequence cross-correlation.
Fig. 3 is the output sequence of STBC signal after local sequence cross-correlation of IEEE802.11n mono-spatial flow two antenna transmission.
Fig. 4 is invention detection method flow chart.
Fig. 5 is the structure chart of instantiation.
Fig. 6 is the output sequence of a spatial flow two antenna STBC signal after instantiation.
Embodiment:
Based on content of the present invention, be applied to frame signal testing process under IEEE802.11gIEEE802.11aIEEE802.11n agreement OFDM pattern, provide concrete implementation step.Receiver adopts 40M clock sampling base band I/Q signal, implements base band to 20M bandwidth single antenna 11n signal, and the frame of 11g signal receives and the frame of double antenna STBC signal is received as example.Input structure adjoint 5 is described below:
1. receiver is sampled to the baseband signal received with 40M sampling rate equally.Cross-correlator carries out computing cross-correlation with the baseband signal of the short leader sequence of 20M bandwidth and input.Output sequence 1.
2. the output of sequence 1 is after postponing 0.8us and being added, and obtains sequence 2.
3. the output of sequence 2 is after postponing 0.4us point and being added, and obtains sequence 3.
4. the output of sequence 2 is added after postponing 0.2us point, obtains sequence 4.
5., for sequence 2, sequence 3, sequence 4, compares with corresponding threshold value respectively, if there is the sequential value on a certain road to be greater than setting threshold, then judgment frame detects successfully, opens follow-up AGC adjusting module.
Module described herein and unit both can adopt hardware implementing, also can adopt software simulating, or the compound mode of software and hardware realizes.The technology of the present invention method is not limited to above-described embodiment, and those skilled in the art are understood that the change can made within the scope of the present invention in various forms and details.Namely the present invention can be used for the system meeting IEEE802.11a standard, IEEE802.11g standard, IEEE802.11n standard.
Claims (4)
1. in WLAN devices to the method that frame signal detects, the frame signal under improving various frame format and under multi-path environment is detected as power, and the method comprises the following steps:
(1) Received signal strength and local sequence are carried out computing cross-correlation, obtain correlated series 1;
(2) be added after correlated series 1 being postponed 0.8us, formation sequence 2;
(3) be added after sequence 2 being postponed 0.4us, formation sequence 3; Be added after sequence 2 is postponed 0.2us, formation sequence 4;
(4) be added after sequence 3 being postponed 0.2us, formation sequence 5;
(5) be added after sequence 4 being postponed 0.1us, formation sequence 6;
(6) be added after sequence 5 being postponed 0.6us, formation sequence 7;
(7) be added after sequence 2 being postponed 0.10us, then be added after postponing 0.05us, then be added after postponing 0.15us, formation sequence 8;
(8) for the frame signal of IEEE802.11g, IEEE802.11a and IEEE802.11n single transmit antenna stream, whether the correlation detecting sequence 2 is greater than setting threshold; Whether the correlation that the frame signal for two transmitting antenna stream MixedFormat patterns detects sequence 3 is greater than setting threshold; For the frame signal of two transmitting antenna stream Greenfield patterns, whether the correlation detecting sequence 4 is greater than setting threshold; For the frame signal of three transmitting antenna stream MixedFormat patterns, whether the correlation detecting sequence 5 is greater than setting threshold; For the frame signal of three transmitting antenna stream Greenfield patterns, whether the correlation detecting sequence 6 is greater than setting threshold; For the frame signal of four antenna stream Greenfield patterns, whether the correlation detecting sequence 8 is greater than setting threshold;
(9) as long as there is certain correlation to be greater than corresponding setting threshold in above-mentioned sequence, then complete the testing process of frame signal, if there is the sequential value on a road to be greater than setting threshold, then judgment frame detects successfully, and correlation is greater than threshold value and refers to that the absolute value of the correlation of correlated series is greater than detection threshold.
2. the method for claim 1, is characterized in that correlation is greater than threshold value and refers to that the absolute value of the correlation of correlated series is greater than detection threshold.
3. the method for claim 1, is characterized in that, for different correlated serieses, adopts different detection thresholds.
4. in WLAN devices to the device that frame signal detects, comprise computing cross-correlation device, postpone adder, threshold comparator, wherein:
The baseband signal of reception and local sequence are carried out computing cross-correlation and are obtained correlated series 1 by described computing cross-correlation device;
Described delay adder is added with correlated series 1 after correlated series 1 is postponed the given time again;
The sequence of carrying out being added and given threshold value compare by described threshold comparator, if the value in a certain moment of the sequence after being added is greater than setting threshold, export index signal;
Postpone to be added after correlated series 1 is postponed 0.8us by adder, formation sequence 2; Be added after sequence 2 is postponed 0.4us, formation sequence 3; Be added after sequence 2 is postponed 0.2us, formation sequence 4; Be added after sequence 3 is postponed 0.2us, formation sequence 5; Be added after sequence 4 is postponed 0.1us, formation sequence 6; Be added after sequence 5 is postponed 0.6us, formation sequence 7; Be added after sequence 2 is postponed 0.10us, then be added after postponing 0.05us, then be added after postponing 0.15us, formation sequence 8;
For the frame signal of IEEE802.11g, IEEE802.11a and IEEE802.11n single transmit antenna stream, whether the correlation that described threshold comparator detects sequence 2 is greater than setting threshold; For two transmitting antenna stream MixedFormat patterns frame signal described in threshold comparator detect the correlation of sequence 3 and whether be greater than setting threshold; For the frame signal of two transmitting antenna stream Greenfield patterns, whether the correlation that described threshold comparator detects sequence 4 is greater than setting threshold; For the frame signal of three transmitting antenna stream MixedFormat patterns, whether the correlation that described threshold comparator detects sequence 5 is greater than setting threshold; For the frame signal of three transmitting antenna stream Greenfield patterns, whether the correlation that described threshold comparator detects sequence 6 is greater than setting threshold; For the frame signal of four antenna stream Greenfield patterns, whether the correlation that described threshold comparator detects sequence 8 is greater than setting threshold; As long as there is certain correlation to be greater than corresponding setting threshold in above-mentioned sequence, then export index signal, complete the testing process of frame signal, if there is the sequential value on a road to be greater than setting threshold, then judgment frame detects successful correlation and is greater than threshold value and refers to that the absolute value of the correlation of correlated series is greater than detection threshold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110255695.4A CN102970688B (en) | 2011-08-31 | 2011-08-31 | A kind of frame signal detection method for WLAN devices and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110255695.4A CN102970688B (en) | 2011-08-31 | 2011-08-31 | A kind of frame signal detection method for WLAN devices and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102970688A CN102970688A (en) | 2013-03-13 |
| CN102970688B true CN102970688B (en) | 2015-11-25 |
Family
ID=47800487
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201110255695.4A Active CN102970688B (en) | 2011-08-31 | 2011-08-31 | A kind of frame signal detection method for WLAN devices and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102970688B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1534909A (en) * | 2003-03-28 | 2004-10-06 | 中国科学技术大学 | Frame detection of orthogonal frequency division multiplex system under moving environment and frame synchronization method |
| CN1758636A (en) * | 2004-10-09 | 2006-04-12 | 北京中电华大电子设计有限责任公司 | Frame detection and synchronous device for radio communication network |
| CN101034970A (en) * | 2006-03-08 | 2007-09-12 | 北京中电华大电子设计有限责任公司 | Valve value self-adaptive selection synchronization signal detection method and device |
| CN201146507Y (en) * | 2007-08-30 | 2008-11-05 | 中科院嘉兴中心微系统所分中心 | Large dynamic range automatic gain control device for intermediate range sensing network |
| CN101730121A (en) * | 2009-11-06 | 2010-06-09 | 山东大学 | Frame detection method of orthogonal frequency division multiplexing (OFDM) access downlink |
-
2011
- 2011-08-31 CN CN201110255695.4A patent/CN102970688B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1534909A (en) * | 2003-03-28 | 2004-10-06 | 中国科学技术大学 | Frame detection of orthogonal frequency division multiplex system under moving environment and frame synchronization method |
| CN1758636A (en) * | 2004-10-09 | 2006-04-12 | 北京中电华大电子设计有限责任公司 | Frame detection and synchronous device for radio communication network |
| CN101034970A (en) * | 2006-03-08 | 2007-09-12 | 北京中电华大电子设计有限责任公司 | Valve value self-adaptive selection synchronization signal detection method and device |
| CN201146507Y (en) * | 2007-08-30 | 2008-11-05 | 中科院嘉兴中心微系统所分中心 | Large dynamic range automatic gain control device for intermediate range sensing network |
| CN101730121A (en) * | 2009-11-06 | 2010-06-09 | 山东大学 | Frame detection method of orthogonal frequency division multiplexing (OFDM) access downlink |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102970688A (en) | 2013-03-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101163124B (en) | Method of implementing multi-input multi-output orthogonal frequency division multiplexing system time synchronization | |
| CN101083647B (en) | Method for realizing synchronization in multi-input multi-output OFDM system | |
| CN1988526B (en) | Synchronizing method for multiple input multiple output orthogonal frequency division multiplex radio system | |
| CN103117965B (en) | A kind of spaceborne ais signal timing frequency deviation combined estimation method and realize system | |
| CN102497349B (en) | Multi-strategy-combined OFDM (Orthogonal Frequency Division Multiplexing) frame synchronization method | |
| CN105007150A (en) | Low-signal-noise-ratio SC-FDE (Single Carrier-Frequency Domain Equalization) system synchronization method and synchronization device | |
| CN101330316B (en) | Time synchronization method and device for up link of wireless communication system | |
| CN101127753A (en) | A channel estimation method applicable to multi-carrier system | |
| CN103763222A (en) | Channel ambiguity removing method in MIMO signal blind detection process | |
| CN101001234B (en) | Method for sending signal by orthogonal frequency division multiplex system and method of cell search | |
| CN105141562A (en) | Communication system and synchronization method thereof | |
| CN104753832A (en) | Secondary synchronization signal (SSS) detection method and device | |
| CN103428153A (en) | Gaussian minimum shift keying (GMSK) signal receiving method in satellite mobile communication | |
| WO2004070980A1 (en) | Transmission device and transmission method | |
| CN107612652B (en) | Small region search method and system based on protenchyma networking protocol | |
| CN104363037A (en) | Rapid detection system and method for detecting quantity of antenna ports of LTE (Long Term Evolution) system | |
| WO2021143649A3 (en) | Signal processing system and related electronic device | |
| CN103023830A (en) | Turbo iteration detecting device and method directing at big carrier frequency excursion | |
| CN102143574A (en) | Timing synchronization method suitable for IEEE (Institute of Electrical and Electronic Engineers) 802.16m preamble structure | |
| CN102404044B (en) | Frame synchronization detecting method for uplink signals in digital wireless trunking communication system based on TDMA (Time Division Multiple Access) technology and frame synchronization detecting device | |
| CN102970688B (en) | A kind of frame signal detection method for WLAN devices and device | |
| CN103078819B (en) | Fine symbol timing synchronization method and device thereof | |
| CN107360624A (en) | A kind of smooth auto-correlation timing coarse synchronization method that targeting sequencing is repeated based on multistage | |
| CN101867543B (en) | A kind of frame arrival detection method based on signal-to-noise ratio (SNR) estimation | |
| WO2012052771A1 (en) | Multicarrier packet synchronisation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: 102209 Beijing, Beiqijia, the future of science and technology in the south area of China electronic network security and information technology industry base C building, Applicant after: Beijing CEC Huada Electronic Design Co., Ltd. Address before: 100102 Beijing City, Chaoyang District Lize two Road No. 2, Wangjing science and Technology Park A block five layer Applicant before: Beijing CEC Huada Electronic Design Co., Ltd. |
|
| COR | Change of bibliographic data | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |