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NO930911L - RECEIVING OF FREQUENCY PARTICULAR ORTHOGONAL MULTIPLE SIGNALS - Google Patents

RECEIVING OF FREQUENCY PARTICULAR ORTHOGONAL MULTIPLE SIGNALS

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Publication number
NO930911L
NO930911L NO93930911A NO930911A NO930911L NO 930911 L NO930911 L NO 930911L NO 93930911 A NO93930911 A NO 93930911A NO 930911 A NO930911 A NO 930911A NO 930911 L NO930911 L NO 930911L
Authority
NO
Norway
Prior art keywords
demodulated
samples
values
frequency
complex
Prior art date
Application number
NO93930911A
Other languages
Norwegian (no)
Other versions
NO930911D0 (en
Inventor
Jeffrey John Gledhill
Santosh Vasudev Anikhindi
Peter Anthony Avon
Original Assignee
Nat Transcommunications 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
Priority claimed from GB909020170A external-priority patent/GB9020170D0/en
Application filed by Nat Transcommunications Ltd filed Critical Nat Transcommunications Ltd
Publication of NO930911D0 publication Critical patent/NO930911D0/en
Publication of NO930911L publication Critical patent/NO930911L/en

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  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

I et OFDM-signal moduleres individuelle OFDM-bærere med sampler av signaler, som kun kan ta et begrenset antall tillatte verdier, og en blokksampler modulerer gruppen av bærere i løpet av en tidsperiode T. I en mottaker kan signalet som modulerer en invididuell OFDM-bærer demoduleres ved å estimere posisjonene til referanseakser som tjener som referanseramme mot hvilken de tillatte modulerende verdiene er definert, og å multiplisere verdiene av de demodulerte samplene med den kompleks-konjugerte for et punkt på én av de estimerte referanseaksene. Spredningen av samplingsgruppene demodulert fra hver OFDM-bærer gir en indikasjon på hvorvidt mottakeren er synkronisert med blokkgrensene. Spredningen av de komplekse samplene evalueres fortrinnsvis kun i radiell retning, og benyttes til å styre samplingsklokkens frekvens. Fase-avdrift av de demodulerte samplene fra én blokk til den neste, indikerer graden av frekvensfeil i lokal oscillator. Fase-avdrift blir fortrinnsvis målt ved å multiplisere komplekse verdier med den kompleks-konjugerte for et tidligere sampel demodulert fra den samme OFDM-bæreren, og ved å benytte det resulterende måltallet til å styre den lokale oscillatorens frekvens via en frekvenslåst sløyfe.In an OFDM signal, individual OFDM carriers are modulated with samples of signals, which can only take a limited number of allowable values, and a block sampler modulates the group of carriers during a time period T. In a receiver, the signal modulating an individual OFDM carrier is demodulated by estimating the positions of reference axes which serve as a reference frame against which the allowable modulating values are defined, and multiplying the values of the demodulated samples by the complex-conjugate for a point on one of the estimated reference axes. The scattering of the sampling groups demodulated from each OFDM carrier provides an indication of whether the receiver is synchronized with the block boundaries. The scattering of the complex samples is preferably evaluated only in the radial direction, and is used to control the frequency of the sampling clock. Phase drift of the demodulated samples from one block to the next indicates the degree of frequency error in the local oscillator. Phase drift is preferably measured by multiplying complex values with the complex conjugate of a previous sample demodulated from the same OFDM carrier, and by using the resulting target number to control the frequency of the local oscillator via a frequency locked loop.

NO93930911A 1990-09-14 1993-03-12 RECEIVING OF FREQUENCY PARTICULAR ORTHOGONAL MULTIPLE SIGNALS NO930911L (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB909020170A GB9020170D0 (en) 1990-09-14 1990-09-14 Orthogonal frequency division multiplexing
PCT/GB1991/001571 WO1992005646A1 (en) 1990-09-14 1991-09-13 Reception of orthogonal frequency division multiplexed signals

Publications (2)

Publication Number Publication Date
NO930911D0 NO930911D0 (en) 1993-03-12
NO930911L true NO930911L (en) 1993-03-12

Family

ID=26297653

Family Applications (1)

Application Number Title Priority Date Filing Date
NO93930911A NO930911L (en) 1990-09-14 1993-03-12 RECEIVING OF FREQUENCY PARTICULAR ORTHOGONAL MULTIPLE SIGNALS

Country Status (1)

Country Link
NO (1) NO930911L (en)

Also Published As

Publication number Publication date
NO930911D0 (en) 1993-03-12

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