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WO2012040905A1 - Procédé et appareil permettant de déterminer l'occupation d'une pluralité de canaux sans fil - Google Patents

Procédé et appareil permettant de déterminer l'occupation d'une pluralité de canaux sans fil Download PDF

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Publication number
WO2012040905A1
WO2012040905A1 PCT/CN2010/077408 CN2010077408W WO2012040905A1 WO 2012040905 A1 WO2012040905 A1 WO 2012040905A1 CN 2010077408 W CN2010077408 W CN 2010077408W WO 2012040905 A1 WO2012040905 A1 WO 2012040905A1
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WO
WIPO (PCT)
Prior art keywords
data streams
datastream
data stream
radio
occupation
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.)
Ceased
Application number
PCT/CN2010/077408
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English (en)
Inventor
Feng Yang
Daqing Gu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
France Telecom Research and Development Beijing Co Ltd
Original Assignee
France Telecom Research and Development Beijing Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by France Telecom Research and Development Beijing Co Ltd filed Critical France Telecom Research and Development Beijing Co Ltd
Priority to PCT/CN2010/077408 priority Critical patent/WO2012040905A1/fr
Priority to PCT/IB2011/002706 priority patent/WO2012042383A1/fr
Publication of WO2012040905A1 publication Critical patent/WO2012040905A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0006—Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio
    • 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
    • H04L27/2668—Details of algorithms
    • H04L27/2669—Details of algorithms characterised by the domain of operation
    • H04L27/2672—Frequency domain
    • 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
    • H04L27/2668—Details of algorithms
    • H04L27/2673—Details of algorithms characterised by synchronisation parameters
    • H04L27/2676—Blind, i.e. without using known symbols
    • H04L27/2678—Blind, i.e. without using known symbols using cyclostationarities, e.g. cyclic prefix or postfix

Definitions

  • the present invention relates in general to a method and apparatus for determining the occupation of a plurality of wireless channels. Particularly, but not exclusively the invention relates to spectrum sensing for cognitive radio systems.
  • Cognitive radio is widely regarded as a promising solution to the current low usage of radio resources. It has the potential to utilize the large amount of unused licensed spectrum while swiftly vacating the occupied channel when a licensed user is detected.
  • a series of techniques including spectrum sensing, real-time spectrum allocation, interference detection etc. are indispensable.
  • fast and reliable spectrum sensing is one of the most important elements for a CR system, since the first task of a CR terminal is to detect the unused frequency holes.
  • Waveform-based spectrum sensing for Chinese digital television terrestrial broadcasting system is described in the document by H. Chen, et al., "Spectrum sensing for DMB-T systems using PN” (Proc. I EEE Int. Conf. Commun., 2008).
  • This document describes a method of spectrum sensing by correlating the received signal with the known pseudo noise (PN) sequence that is specified in the Chinese digital broadcasting standard.
  • PN pseudo noise
  • Such waveform-based approaches can be applied in a very low SNR situation, but they require that known patterns (e.g. a PN sequence in this case) should be inserted in the transmission signal which is not always satisfied in practical systems.
  • cyclostationarity (I EEE Trans. Signal Process., Vol. 42, No.9, 1994), which proposes time-domain and frequency-domain optimal tests to detect the presence of cyclostationarity. Cyclostationarity-based spectrum sensing is also described in the document by H. Chen and W. Gao, "Apparatus and method for sensing a signal using cyclostationarity” (PCT patent, No. : WO 20081 108797 Al), which proposes an Advanced Television Systems Committee (ATSC) signal detector by selecting one of a number of ATSC channels and determining the cyclostationary feature of the signal on the selected channel.
  • ATSC Advanced Television Systems Committee
  • Cyclostationarity-based approach can be a good trade-off between performance and requirements on system's deployment, since it allows for detecting communication signals at low SNR regime while only assumes that parameter like symbol rate is known a priori.
  • SCF cyclic correlation or spectral correlation function
  • a registered frequency band is composed of from several to several hundred channels (e.g. a GSM downlink band is divided into 1 20 channels and the bandwidth of a single channel is 200KHz).
  • the feasible way for a CR terminal that has to locate the unused frequency spectrum is to detect the cyclostationarity of each channel one by one, which is inefficient as well as computationally intensive.
  • a first aspect of the invention provides a computer implemented method of determining the occupation of a plurality of radio-frequency channels, the method comprising : collecting baseband data streams from a plurality L of radio-frequency channels; performing a transformation on each data stream to modify a cyclo-stationary parameter of said each data stream ; combining the transformed data streams to generate a combined datastream ; and performing cyclostationarity detection on the combined datastream to determine the occupation of the plurality of radio frequency channels.
  • a second aspect of the invention provides an apparatus for determining the occupation of a plurality of radio-frequency channels, the apparatus comprising : data stream collection means for collecting baseband data streams from a plurality of L radio-frequency channels; transformation means for performing a
  • the step of collecting baseband data streams comprises collecting the data streams in series at different time slots
  • each datastream is characterised by a central frequency and wherein each datastream is collected by tuning the frequency of a local oscillator of a receiving device receiving the datastream signals to the central frequency of each data stream sequentially.
  • the step of collecting baseband data streams comprises collecting at least a portion of the data streams in parallel at the same time slot.
  • the step of performing a transformation comprises upsampling, by an upsampling integer factor J, each sample of the respective data stream to derive transformed samples, and wherein (J-1 ) zeros are padded between every two samples of the data stream.
  • the method further includes smoothing each upsampled signal by an interpolation filter.
  • the step of combining the transformed data streams comprises linearly summing the data streams.
  • the step of performing cyclostationarity detection on the combined datastream comprises: computing a discrete Fourier transform (FFT) on a segment of the combined data stream ; correlating the discrete Fourier transformed segment for a plurality of RF channels; averaging the correlated segment; multiplying the averaged segment by a weighting factor; and comparing the weighted segment with a threshold parameter to determine occupation of the corresponding RF channel.
  • FFT discrete Fourier transform
  • the step of averaging comprises averaging the output of the correlation step over Q datablocks by computing ⁇ f + a)z * X) (f - )
  • the proposed method and system may jointly detect the cyclostationarity of multiple channels while keeping the
  • At least part of the methods according to the invention may be computer implemented.
  • the methods may be implemented in software on a programmable apparatus. They may also be implemented solely in hardware or in software, or in a combination thereof.
  • a tangible carrier medium may comprise a storage medium such as a floppy disk, a CD-ROM, a hard disk drive, a magnetic tape device or a solid state memory device and the like.
  • a transient carrier medium may include a signal such as an electrical signal, an electronic signal, an optical signal, an acoustic signal, a magnetic signal or an electromagnetic signal, e.g. a microwave or RF signal.
  • Figure 1 is a flow chart of a method of determining occupation of a plurality of wireless channels according to a general embodiment of the invention
  • Figure 2 is an apparatus for collecting datastreams according to an embodiment of the invention
  • Figure 3 is an apparatus for collecting datastreams according to an alternative embodiment of the invention
  • Figure 4 is an apparatus for upsampling datastreams according to an embodiment of the invention
  • Figure 5 is an apparatus for performing datastream transformation according to an embodiment of the invention.
  • Figure 6 is an example of a SCF map of a signal with symbol rate f s in which peaks corresponding to f s 2f s and 3f s can be identified;
  • Figure 7 is an example of a SCF map according to an embodiment of the
  • Figure 8 is an example of a SCF map according to an alternative embodiment of the invention.
  • Figure 9 is an apparatus for performing cyclostationarity for U channels sharing a FFT module according to an embodiment of the invention.
  • Figure 10 is an apparatus for performing cyclostationarity according to the prior art.
  • the data streams can be collected from the same RF front-end at different time slots or from different RF front-ends at the same time slot.
  • L' L/K, where K is an integer.
  • the purpose of this operation is to enable different RF channels to have different symbol rates. Since cyclostationarity (e.g. correlated frequency) has a one to one mapping with the symbol rate, in a subsequent step, i.e. for cyclostationarity detection, different channels are resolvable because they have different symbol rates.
  • step S1 03 the L' transformed data streams are linearly combined (for example summed) to generate a single stream which can be referred to as an observation stream.
  • step S1 04 a cyclostationarity test is performed on the observation stream in step S1 04 to determine the occupation of the L' channels. If K > 1 , steps S1 02 to S1 04 are repeated K-1 times until the L channels are all detected.
  • the input to a CR terminal is a RF signal containing a plurality of wireless RF channels which are characterized by their respective central frequency f- ⁇ , f L ,
  • FIG. 2 is a schematic diagram of a RF-to-baseband module device 1 0, the main elements of which include an antenna 1 1 for receiving RF signals, a local oscillator (LO) 1 2, two down-converters 1 3-1 , 1 3-2 and two analog-to-digital converters (ADC) 14-1 , 14-2.
  • data streams are collected using the same RF-to-baseband module 1 0 at different time slots by tuning the central frequency of the LO 1 2 to frequencies f- ⁇ , f L sequentially.
  • a second embodiment of an apparatus for implementing step S1 01 for collecting baseband data streams will be described with reference to Figure 3.
  • FIG 3 is a schematic diagram of a RF-to-baseband apparatus comprising an array of L RF-to-baseband modules 1 0 as illustrated in Figure 3.
  • Data streams are collected using a plurality of RF-to-baseband modules but at the same time slot.
  • further embodiment of the apparatus can be easily derived by changing the number of element modules in the array, e.g. L/2, L/3 etc.
  • the output of this module i.e. datastreams x-i , x 2 , ... Xi_ are collected for further processing.
  • the objective of signal transformation step S102 is to change the cyclo- stationary feature of the original signal so that different signals may be resolved after linearly combining them to produce a single stream.
  • up-sampling by an integer factor is employed as the realization of signal transformation.
  • alternative transformations e.g. rational up-sampling, integral down-sampling and rational down-sampling
  • cyclo-stationary feature may be applied within the scope of the invention.
  • step S1 12 (J - 1 ) zeros are padded between every two samples of the original data sequence x(n) to generate signal v(m) which can be formulated as:
  • step S1 13 signal v(m) ⁇ s smoothed by an interpolation filter to produce the final output y(m).
  • upsampling factor Jj's is essential to accurately identify the existence of multiple channels from the single linearly combined stream Zj(k) due to the inter-signal inference in the spectral correlation domain, since peaks will appear at locations corresponding to n/ s (ne N) other than f s , in the map of SCF as shown in Fig. 6, where f s , is the symbol rate of the signal.
  • FIG. 9 An embodiment of the apparatus implemented for the cyclostationarity detection for L' channels is depicted in Fig. 9, and comprises one N-point FFT module S1 15, L' correlating modules S1 16 , L' averaging modules S1 17 and L' feature detection modules S1 18.
  • ⁇ (N - 1)) can be calculated, where f sa mpie is the sampling rate of the ADC and always a multiple of f s , the FFT size N should be a number like K x J x J 2 x.... xJu-i , where K ⁇ s an integer.
  • Feature detect module S1 18 adds the energy of the output of the averaging module multiplied by weighting factor w ⁇ £) , Le. T jilO Si , f+a)Z*, ⁇ - ) ⁇ w(f) and compares the sum with a threshold to infer the occupation of the detected channel.
  • the implementation of the conventional cyclostationarity detection method is also provided as shown in Fig.10, which includes an N-point FFT module, a correlating module, an averaging module and a feature detection module.
  • the exemplary implementation of the invention is made up of U parallel branches, and each branch is part of the implementation of the conventional cyclostationarity detection method.
  • the exemplary implementation employs only one FFT module which is the most computationally intensive component and shared among the L' branches.
  • a rough estimation of the complexity reduction of the invention over the conventional method can be carried out as follows. For detecting L' channels, the invention needs Q FFTs while the conventional method needs L'Q FFTs. So the invention could save roughly ( .' - !Q / .' FFTs per channel detection.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)

Abstract

L'invention concerne un procédé informatisé et un appareil permettant de déterminer l'occupation d'une pluralité de canaux de radiofréquence. Ce procédé consiste : à collecter des flux de données de bande de base à partir d'une pluralité de L canaux de radiofréquence; à réaliser une transformation sur chaque flux de données pour modifier un paramètre cyclo-stationnaire dudit flux; à combiner les flux de données transformés pour générer un flux de données combiné; et à effectuer une détection de cyclo-stationnarité sur les flux de données combinés pour déterminer l'occupation de la pluralité de canaux de radiofréquence.
PCT/CN2010/077408 2010-09-28 2010-09-28 Procédé et appareil permettant de déterminer l'occupation d'une pluralité de canaux sans fil Ceased WO2012040905A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/CN2010/077408 WO2012040905A1 (fr) 2010-09-28 2010-09-28 Procédé et appareil permettant de déterminer l'occupation d'une pluralité de canaux sans fil
PCT/IB2011/002706 WO2012042383A1 (fr) 2010-09-28 2011-09-28 Procédé et appareil permettant de déterminer le spectre simultané d'une pluralité de canaux sans fil par détection d'éléments cyclostationnaires

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Application Number Priority Date Filing Date Title
PCT/CN2010/077408 WO2012040905A1 (fr) 2010-09-28 2010-09-28 Procédé et appareil permettant de déterminer l'occupation d'une pluralité de canaux sans fil

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PCT/IB2011/002706 Ceased WO2012042383A1 (fr) 2010-09-28 2011-09-28 Procédé et appareil permettant de déterminer le spectre simultané d'une pluralité de canaux sans fil par détection d'éléments cyclostationnaires

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CN110601971B (zh) * 2019-09-17 2021-10-26 南京林业大学 一种数据传输方法、装置、电子设备及存储介质

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101630983A (zh) * 2009-07-30 2010-01-20 哈尔滨工业大学 认知无线电中利用循环谱统计量的空闲频谱检测方法
CN101753232A (zh) * 2009-12-16 2010-06-23 北京航空航天大学 协作频谱检测方法和系统

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CN101371569B (zh) * 2006-01-17 2011-07-27 皇家飞利浦电子股份有限公司 使用周期平稳工具箱检测嵌入到噪声中的电视信号的存在
US8077676B2 (en) * 2007-01-07 2011-12-13 Futurewei Technologies, Inc. System and method for wireless channel sensing
JP2010520704A (ja) 2007-03-08 2010-06-10 トムソン ライセンシング 周期定常性を用いて信号を検知する装置及び方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101630983A (zh) * 2009-07-30 2010-01-20 哈尔滨工业大学 认知无线电中利用循环谱统计量的空闲频谱检测方法
CN101753232A (zh) * 2009-12-16 2010-06-23 北京航空航天大学 协作频谱检测方法和系统

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