OFDM data demodulators synchronization

A synchronization method for data demodulation in an OFDM radio receiver, comprising the steps of:

• computing includes constraining the reference signal so as to make it insensitive to timing misalignment;
• computing includes constraining the reference signal so as to make it insensitive to frequency offset;
• computing a reference signal that is insensitive to any other parametrizable impairment;
• computing an inner product between the received signal and this constrained reference signal;
• and
• assuming an index of the maximum of the result is the index of the start of the long preamble sequence.

A synchronization method for data demodulation in an OFDM radio receiver, comprising the steps of:

• sampling and measuring an OFDM radio transmission to obtain a series of received-signal samples that represent a short preamble, a long preamble guard interval (GI), and a first long preamble, respectively;
• massaging of the samples around x(n+32) can be performed so as to achieve a “coherent” copy of the samples around x(n) and x(n+64)
• 7 z -> B = [ - x ⁡ ( n + 32 ) ⁢ flipud ⁡ ( conj ⁡ ( x ⁡ ( n + 32 - 1 :
• - 1 :
• n + 32 - N ) ) ) ] z -> F = [ - x ⁡ ( n + 32 ) ⁢ flipud ⁡ ( conj ⁡ ( x ⁡ ( n + 32 + 1 :
• 1 :
• n + 32 + N ) ) ) ] ⁢ y ⁢ ( n ) = ⁢ [LeftDoubleBracketingBar] ∑ k = 0 N - 1 ⁢ { x ⁡ ( n - k ) + x ⁡ ( n - k + 64 ) + z -> B ⁡ ( k ) } ⁢ { x ⁡ ( n + k ) + ⁢ x ⁢ ( n + k + 64 ) + z -> F ⁡ ( n ) } [RightDoubleBracketingBar] 2
• assuming an index of the maximum of the result is the index of the start of the first long preamble;
• subtracting a corresponding number of samples to find a first received-signal sample of said long preamble guard interval (GI);
• and
• identifying said first sample of said long preamble GI to synchronize any data demodulation of subsequent parts of said OFDM radio transmission.

A synchronization method for data demodulation in an OFDM radio receiver, comprising the steps of:

• sampling and measuring an OFDM radio transmission to obtain a series of received-signal samples that represent a short preamble, a long preamble guard interval (GI), and a first long preamble, respectively;
• the vector inner products (complex) result) of the previous and subsequent samples starting at x(n) and x(n+32) are added and then collect the sample at x(n+64+32)
• 8 y ⁡ ( n ) = [LeftDoubleBracketingBar] ∑ k = 0 N - 1 ⁢ x ⁡ ( n - k ) ⁢ x ⁡ ( n + k ) + ∑ k = 0 N - 1 ⁢ x ⁡ ( n + 32 - k ) ⁢ x ⁡ ( n + 32 + k ) [RightDoubleBracketingBar] 2
• assuming an index of the maximum of the result is the index of the start of the first long preamble;
• subtracting a corresponding number of samples to find a first received-signal sample of said long preamble guard interval (GI);
• and
• identifying said first sample of said long preamble GI to synchronize any data demodulation of subsequent parts of said OFDM radio transmission.