Process for providing a pilot aided phase synchronization of carrier

• US 7,409,024 B2
• Filed: 09/01/2004
• Issued: 08/05/2008
• Est. Priority Date: 09/05/2003
• Status: Expired due to Fees

• Current Assignee: Agence Spatiale Europeenne
• Original Assignee: Agence Spatiale Europeenne
• Inventors: De Gaudenzi, Riccardo, Ginesi, Alberto, Bigi, Alan, Fittipaldi, Domenico
• Primary Examiner(s): Payne; David C.
• Assistant Examiner(s): NGUYEN, LEON VIET Q
• Application Number:
  US10/930,864
• Publication Number:
  US 20050111603A1
• Time in Patent Office: 1,434 Days
• Field of Search: 375/316, 375/340, 375/362
• US Class Current: 375/362
• CPC Class Codes: H04L 2027/0032 at baseband and passband
• CPC Class Codes: H04L 2027/0046 Open loops
• CPC Class Codes: H04L 2027/0057 quadrature phase
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657

Abstract

A process for providing a phase synchronization of a pilot aided carrier of an input digital signal z(k), the signal z(k) having signal fields of L_s symbol signals, namely a block of L_P pilot symbol signals Z^P_(k) and a data field of (L_s−L_P) data symbol signals Z^d_(k), and characterized for each signal field (l) by:

• • extracting the pilot symbol signals Z^P_(k) and
  • calculating an unwrapped phase estimate {circumflex over (θ)}(lL_s) over the pilot block of said signal field (1) and:
  • interpolating said unwrapped phase estimates of successive signal fields (l, +1 . . . ) with a Wiener interpolator having M taps to obtain interpolated phase estimates having a Minimum Mean Square Error;
  • providing linear interpolation between said interpolated phase estimates to obtain phase correction estimates ({circumflex over (θ)}(k_s)) over the data field of said signal fields;
  • calculating from said phase correction estimates ({circumflex over (θ)}(k_s)) a phase correction (e^{−j{circumflex over (θ)}(ks)}) to be applied to said signal Z(k).

Claims

1. A process for providing a phase synchronization of a pilot aided carrier of an input digital signal z(k), said signal z(k) comprising signal fields comprised of L_s symbol signals, namely a block of L_P pilot symbol signals Z^P_(k) and a data field of (L_s −

L_P) data symbol signals Z^d_(k), k_s being a symbol index for phase correction estimates, k_s=0 corresponding to the pilot block, and characterized in that it comprises for each signal field (l);

extracting the pilot symbol signals Z^P_(k) and

calculating an unwrapped phase estimate {circumflex over (θ

)}(lL,) over the pilot block of said signal field (l) and;

interpolating said unwrapped phase estimates of successive signal fields (l, l+1 . . . . ) only for k_s=0 with a Wiener interpolator having M taps to obtain interpolated phase estimates having a Minimum Mean Square Error;

providing linear interpolation between said interpolated phase estimates to obtain phase correction estimates ({circumflex over (θ

)}(k_s)) over the data field of said signal fields;

calculating from said phase correction estimates ({circumflex over (θ

)}(k_s)) a phase correction (e<sup>−

j{circumflex over (θ

)}(ks)</sup>) to be applied to said signal z(k).

2. A process as in claim 1, wherein the Wiener filter coefficients γ

of said taps are determined using the phase noise (PSD) and the signal to noise ratio (SNR) of the signal.

3. A process as in claim 2, wherein said phase noise is the worst case phase noise and said signal to noise ratio is the nominal signal to-noise ratio.

4. A process as in claim 1, wherein the Wiener filter taps are scaled by the ratio

$1/\sum _{}^{}$

m = - M M ⁢

⁢

γ

⁡

( m )

so that the sum of the coefficients of the Wiener filter taps is equal to 1.

5. A process for providing a phase synchronization of a pilot aided carder of an input digital signal z(k), said signal z(k) comprising signal fields comprised of L_s symbol signals, namely a block of L_P pilot symbol signals Z^P_(k) and a data field of (L_s−

L_P) data symbol signals Z^d_(k), and characterized in that it comprises for each signal field (l);

extracting the pilot symbol signals Z^P_(k) and

calculating an unwrapped phase estimate {circumflex over (θ

)}(lL_s) over the pilot block of said signal field (l) and;

interpolating said unwrapped phase estimates of successive signal fields (l, l+1 . . . . ) with a Wiener interpolator having M taps to obtain interpolated phase estimates having a Minimum Mean Square Error;

providing linear interpolation between said interpolated phase estimates to obtain phase correction estimates ({circumflex over (θ

)}(k_s)) over the data field of said signal fields;

calculating from said phase correction estimates ({circumflex over (θ

)}(k_s)) a phase correction (e<sup>−

j{circumflex over (θ

)}(ks)</sup>) to be applied to said signal z(k), wherein the Wiener filter coefficients γ

of said taps are determined using the phase noise (PSD) and the signal to noise ratio (SNR) of the signal and wherein said phase noise is the worst case phase noise and said signal to noise ratio is the nominal signal to-noise ratio.

6. A process for providing a phase synchronization of a pilot aided carrier of an input digital signal z(k), said signal z(k) comprising signal fields comprised of L_s symbol signals, namely a block of L_P pilot symbol signals Z^P_(k) and a data field of (L_s−

L_P) data symbol signals Z^d_(k), and characterized in that ft comprises for each signal field (l);

extracting the pilot symbol signals Z^P_(k) and

calculating an unwrapped phase estimate {circumflex over (θ

)}(lL_s) over the pilot block of said signal field (l) and;

interpolating said unwrapped phase estimates of successive signal fields (l, l+1 . . . . ) with a Wiener interpolator having M taps to obtain interpolated phase estimates having a Minimum Mean Square Error;

providing linear interpolation between said interpolated phase estimates to obtain phase correction estimates ({circumflex over (θ

)}(k_s)) over the data field of said signal fields;

calculating from said phase correction estimates ({circumflex over (θ

)}(k_s)) a phase correction (e−

j{circumflex over (θ

)}(k^s)) to be applied to said signal z(k), wherein the Wiener filter taps are scaled by the ratio

$1/\underset{m=-M}{\overset{M}{\sum <br><br>}}<br><br><br><br>\mathrm{\gamma <br><br>}<br><br>\left(m\right)$

so That the sum of the coefficients of the Wiener filter taps is equal to 1.