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| | I'm a 41 years old, married and working at the college (Human Ecology).<br>In my spare time I try to teach myself Japanese. I've been twicethere and look forward to go there sometime in the future. I love to read, preferably on my kindle. I like to watch Family Guy and Sons of Anarchy as well as docus about anything scientific. I like Backpacking.<br><br>Look into my homepage ... [http://tweak.s341.xrea.com/drupal6/node/314308 информативным сообщение] |
| '''Binary Offset Carrier''' (BOC) modulation <ref>ION-AM99</ref><ref>MITRE00</ref> currently used in [[Galileo (satellite navigation)|Galileo]] <ref>SIS-ICD08</ref> is a square sub-carrier [[modulation]], where a signal is multiplied by a rectangular [[sub-carrier]] of frequency <math>f_{sc}</math> equal or higher to the [[chip (CDMA)]] rate. Following this [[sub-carrier]] [[multiplication]], the [[spectrum]] of the signal is divided into two parts, therefore BOC modulation is also known as a split-spectrum modulation. | |
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| The main idea behind BOC modulation is to reduce the interference with [[BPSK]]-modulated signal, which has a [[sinc function]] shaped spectrum. Therefore, BPSK-modulated signals such as C/A [[GPS]] codes have most of their spectral energy concentrated around the carrier frequency, while BOC-modulated signals (used in [[Galileo system]]) have low energy around the carrier frequency and two main spectral lobes further away from the carrier (thus, the name of split-spectrum).
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| BOC modulation has several variants: sine BOC (SinBOC),<ref name="ENC-GNSS04">ENC-GNSS04</ref><ref>ION-GPS02</ref> cosine BOC (CosBOC)<ref name="ENC-GNSS04" /><ref>GJU</ref><ref name="Wiley06">Wiley06</ref> Alternative BOC (AltBOC),<ref>Septentrio</ref><ref>GPSJournal07</ref><ref>Margaria08</ref><ref>IEE06</ref> multiplexed BOC ([[MBOC]]),<ref>InsideGNSS07</ref><ref>ION-GNSS07</ref><ref>ION-GNSS07bis</ref><ref>EW07</ref><ref>ESA06</ref> Double BOC (DBOC) <ref name="Wiley06" /> etc. and some of them have been currently selected for Galileo [[GNSS]] signals.
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| A BOC waveform is typically denoted via BOC(m,n) or BOC<math>(f_{sc}\;,f_c)</math>, where <math>f_{sc}</math> is the sub-carrier frequency, <math>f_c</math> is the chip frequency, <math>m=f_{sc}/f_{ref}</math>, <math>n=f_{c}/f_{ref}</math>, and <math>f_{ref}=1.023</math> Mcps is the reference chip frequency of C/A [[GPS]] signal.
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| A sine BOC(1,1) modulation is similar to [[Manchester code]], that is, in digital domain, a '+1' is encoded as a '+1 −1' sequence, and a '0' is encoded as a '−1 +1' sequence.
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| For an arbitrary <math>N_{BOC}=2m/n</math> modulation order, in sine BOC(m,n) case, a '+1' is encoded as an alternating sequence of '+1 −1 +1 −1 +1 ...', having <math>N_{BOC}</math> elements, and a '0' (or '−1') is encoded as an alternating '−1 +1 ...' sequence, also having <math>N_{BOC}</math> elements.
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| BOC modulation is typically applied on [[CDMA]] signals, where each chip of the [[pseudorandom]] code is split into BOC sub-intervals, as explained above (i.e., there are <math>N_{BOC}</math> BOC intervals per chip).
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| The [[Spectral density|power spectral density]] of a BOC-modulated signal depends on the BOC modulation order <math>N_{BOC}=2\frac{f_{sc}}{f_c}=2\frac{m}{n}</math> and its derivation can be found, for example, in
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| <ref name="Wiley06" /><ref>VTC04</ref>
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| ==References==
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| {{Reflist}}
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| {{Refbegin}}
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| *Betz J. The offset carrier modulation for GPS modernization. In Proceedings of ION Technical meeting, (Cambridge, Massachusetts) June 1999; 639–648. (ION-AM99)
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| *J. Betz, “Design and performance of code tracking for the GPS M code signal,” MITRE, Mclean, Va, USA, September 2000, http://www.mitre.org/work/tech_papers/tech_papers_00/ betz_codetracking/ (MITRE00)
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| * Galileo Open Service Signal in Space Interface Control Document http://www.gsa.europa.eu/go/galileo/os-sis-icd/galileo-open-service-signal-in-space-interface-control-document (SIS-ICD08)
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| *Hein G, Irsigler M, Rodriguez JA, Pany T. Performance of Galileo L1 signal candidates. In CDROM Proceedings of European Navigation Conference GNSS, May 2004. (ENC-GNSS04)
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| * Ries L, Lestarquit L, Armengou-Miret E, et al. A software simulation tool for GNSS2 BOC signals analysis. In Proceedings of ION GPS, (Portland, OR) September 2002; 2225-2239 (ION-GPS02)
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| * GJU. Galileo standardisation document for 3GPP. Galileo Joint Undertaking (GJU) webpages, http://www.galileoju.com/page.cfm?voce=s2&idvoce=64&plugIn=1 (GJU)
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| *www.septentrio.com/papers/GallileoAltBOC_paperFinal.pdf
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| *E. S. Lohan, A. Lakhzouri, and M. Renfors, “Binary-offset-carrier modulation techniques with applications in satellite navigation systems,” Wiley Wireless Communications and Mobile Computing, vol. 7, no. 6, pp. 767–779, 2006, http://www3.interscience.wiley.com/cgi-bin/fulltext/112693999/PDFSTART (Wiley06)
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| * Raghavan SH, Holmes JK. Modeling and simulation of mixed modulation formats for improved CDMA bandwidth efficiency. In Proceedings of Vehicular Technology Conference 2004; 6: 4290-4295 (VTC04).
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| * D. Margaria, F. Dovis, P. Mulassano, An Innovative Data Demodulation Technique for Galileo AltBOC Receivers, Journal of Global Positioning Systems, Journal of Global Positioning Systems, Vol.6, No.1, pp. 89–96, ISSN: 1446-3156, 2007, http://www.gmat.unsw.edu.au/wang/jgps/v6n1/v6n1p10.pdf (GPSJournal07)
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| * D. Margaria, F. Dovis, P. Mulassano, Galileo AltBOC Signal Multiresolution Acquisition Strategy, IEEE Aerospace and Electronic Systems Magazine, Vol.23, No.11, pp. 4–10, ISSN: 0885-8985, November 2008. (Margaria08)
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| * E. S. Lohan, A. Lakhzouri, M. Renfors, ``Complex Double-Binary-Offset-Carrier modulation for a unitary characterization of Galileo and GPS signals'', IEE Proceedings on Radar, Sonar, and Navigation, vol. 153(5), pp. 403-408, Oct 2006.[IEE06]
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| * Avila-Rodriguez, J.A., Hein, G.W., Wallner, S., Issler, J.L., Ries, L., Lestarquit, L., De Latour, A., Godet, J., Bastide, F., Pratt, T., Owen, J. The MBOC Modulation- A Final Touch for the Galileo Frequency and Signal Plan, http://www.insidegnss.com/node/174 (InsideGNSS07)
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| *Avila-Rodriguez, J.A., Wallner, S., Hein, G.W., Eissfeller, B., Irsigler, M., Issler, J.L.: A vision on new frequencies, signals and concepts for future GNSS systems, Proceedings of ION GNSS 2007, Fort Worth, Texas, USA, 25–28 September 2007 (ION-GNSS07)
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| *Avila-Rodriguez, J.A., Hein, G.W., Wallner, S., Issler, J.L., Ries, L., Lestarquit, L., De Latour, A., Godet, J., Bastide, F., Pratt, T., Owen, J.: The MBOC Modulation: The Final Touch to the Galileo Frequency and Signal Plan, Proceedings of ION GNSS 2007, Fort Worth, Texas, USA, 25–28 September 2007 (ION-GNSS07bis)
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| * E.S. Lohan and M. Renfors, ``On the performance of Multiplexed-BOC (MBOC) modulation for future GNSS signals'', in Proc. of European Wireless Conference, Apr 2007, Paris, France.(EW07)
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| *Avila-Rodriguez J.A., Wallner S., Hein G.W.: MBOC: The New Optimized Spreading Modulation Recommended for Galileo E1 OS and GPS L1C, ESA Navitec 2006, Noordwijk, The Netherlands, 11-13 Dec. 2006 (ESA06)
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| {{Refend}}
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| ==External links==
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| * Binary Offset Carrier (BOC) signal generator in Matlab, http://www.mathworks.com/matlabcentral/fileexchange/12829
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| {{DEFAULTSORT:Binary Offset Carrier}}
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| [[Category:Quantized radio modulation modes]]
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I'm a 41 years old, married and working at the college (Human Ecology).
In my spare time I try to teach myself Japanese. I've been twicethere and look forward to go there sometime in the future. I love to read, preferably on my kindle. I like to watch Family Guy and Sons of Anarchy as well as docus about anything scientific. I like Backpacking.
Look into my homepage ... информативным сообщение