Synchronization method and system for a digital receiver

An apparatus for synchronizing carrier frequency offset in a modulated OFDM input signal, the signal having a first symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having pseudoperiodicity, comprising:

• means for obtaining a fractional carrier frequency offset, and
• means for obtaining an integral carrier frequency offset coupled to an output of said means for obtaining fractional carrier frequency offset, wherein said integral frequency offset is obtained through a matched filtering process, including
• circuit means for generating and for shifting a plurality of second symbols,
• means for compensating the second symbol of the input signal with said fractional carrier frequency;
• and
• means for multiplying said compensated second symbol with said plurality of generated and shifted second symbols.

An apparatus for synchronizing carrier frequency offset in a modulated OFDM input signal, the signal having a first symbol being the first symbol of the input signal and having substantially less signal power than a second symbol the second symbol having pseudoperiodicity, comprising:

• means for obtaining a fractional carrier frequency offset;
• means for obtaining an integral carrier frequency offset coupled to an output of said means for obtaining fractional carrier frequency offset, wherein said integral frequency offset is obtained through a matched filtering process;
• and
• tracking means coupled to said means for obtaining integral carrier frequency offset for comparing an output of said means for obtaining integral carrier frequency offset with .DELTA. to determine whether synchronization has been lost.

An apparatus for synchronizing carrier frequency offset in a modulated OFDM input signal, the signal having a first symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having pseudoperiodicity, comprising:

• means for obtaining a fractional carrier frequency offset;
• means for obtaining an integral carrier frequency offset coupled to an output of said means for obtaining fractional carrier frequency offset, wherein said integral frequency offset is obtained through a matched filtering process;
• and
• tracking means coupled to said means for obtaining fractional carrier frequency offset for comparing an output of said means for obtaining integral carrier frequency offset with a threshold to determine whether synchronization has been lost.

An apparatus for synchronizing carrier frequency offset in a modulated OFDM input signal, the signal having a first symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having pseudoperiodicity, comprising:

• means for obtaining a fractional carrier frequency offset;
• and
• means for obtaining an integral carrier frequency offset coupled to an output of said means for obtaining fractional carrier frequency offset, wherein said integral frequency offset is obtained through a matched filtering process, comprising
• peak detection means for providing amplitude and position of a peak signal;
• a memory coupled to said peak detection means for retaining a plurality of amplitudes and positions of peak signals provided from said peak detection means;
• and
• means coupled to said memory for comparing said plurality of amplitudes stored in said memory and for determining one having the largest amplitude.

An apparatus for synchronizing carrier frequency offset in a modulated OFDM input signal, the signal having a first symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having pseudoperiodicity, comprising:

• means for obtaining a fractional carrier frequency offset, and
• means for obtaining an integral carrier frequency offset coupled to an output of said means for obtaining fractional carrier frequency offset wherein said integral frequency offset is obtained through a matched filtering process, including
• peak detection means for providing amplitude and position of a peak signal;
• and
• selector means coupled to said plurality of peak detection means for comparing outputs of said plurality of peak detection means.

An apparatus for synchronizing carrier frequency offset in a modulated OFDM input signal, the signal having a first symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having pseudoperiodicity, comprising:

• means for obtaining a fractional carrier frequency offset, and
• means for obtaining an integral carrier frequency offset coupled to an output of said means for obtaining fractional carrier frequency offset, wherein said integral frequency offset is obtained through a matched filtering process, including
• fast Fourier transform means for transforming a product of the input signal and said output of said means for obtaining fractional carrier frequency offset;
• multiplying means respectively connected to said fast Fourier transform means and frequency shifted phase reference means for multiplying outputs of said fast Fourier transform means and said frequency shifted phase reference means;
• inverse fast Fourier transform means coupled to said multiplying means for inversely transforming an output of said multiplying means;
• and
• peak detection means coupled to said inverse fast Fourier transform means for detecting a peak of an output of said inverse fast Fourier transform means.

A method for synchronizing a carrier frequency offset of a modulated OFDM input signal, the input signal having a first OFDM symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having pseudoperiodicity, comprising:

• estimating a fractional frequency offset of the carrier frequency offset;
• and
• obtaining an integral frequency offset of the carrier frequency offset through a matched filtering process, said process being triggered by said estimated fractional frequency offset and including
• obtaining a first peak amplitude by matching the input signal with a second symbol corresponding to a first integral frequency offset;
• obtaining a second peak amplitude by matching the input signal with a second symbol corresponding to a second integral frequency offset;
• comparing and storing the larger of said first peak amplitude and said second peak amplitude;
• and
• repeating said obtaining and comparing for all possible integral frequency offsets for said estimated fractional frequency offset.

A method for synchronizing a carrier frequency offset of a modulated OFDM input signal, the input signal having a first OFDM symbol being the first symbol of the input signal and having substantially less signal power than a second symbol, the second symbol having, pseudoperiodicity, comprising:

• estimating a fractional frequency offset of the carrier frequency offset;
• and
• obtaining an integral frequency offset of the carrier frequency offset through a matched filtering process, said process being triggered by said estimated fractional frequency offset, wherein said obtaining integral frequency offset includes,
• generating a plurality of second symbols;
• shifting said plurality of second symbols;
• compensating the second symbol of the input signal with said fractional frequency offset;
• and
• multiplying said plurality of shifted second symbols with said compensated second symbol.