Training signal in a single carrier transmission

1. A method for enhancing reception of a single carrier signal, the single carrier signal including a periodic training signal and data; the periodic training signal includes N symbols and L symbols, wherein L<N that constitute either a start portion or an end portion of said N symbols; the method comprising the step of:

(a) duplicating for each training signal said L symbols to the end portion of the training signal if said L symbols constitute a start portion, or otherwise, duplicating for each training signal said L symbols to the start portion of the training signal if said L symbols constitute an end portion, so as to constitute a modified training signal having a duplicated extension.

2. The method according to claim 1 , further comprising:

(b) calculating a channel model utilizing at least the modified training signal in said single carrier signal.

3. The method according to claim 1 , wherein said single carrier signal being a VSB signal.

4. The method according to claim 1 , wherein said single carrier signal being a QAM signal.

5. A method for enhancing reception of a single carrier signal, the single carrier signal including a periodic training signal and data; the periodic training signal includes N symbols and L symbols, wherein L<N that constitute either a start portion or an end portion of said N symbols; in respect of each training signal the method comprising the steps of:

(a) duplicating said L symbols to the end portion of the training signal if said L symbols constitute a start portion, or otherwise, duplicating said L symbols to the start portion of the training signal if said L symbols constitute an end portion, so as to constitute a modified training signal having a duplicated extension; transmitting said single carrier signal; and,

(b) receiving said transmitted single carrier signal and in respect of each modified training signal applying at least the steps of:

(b1) calculating at least IIR coefficients utilizing the modified training signal; and,

(b2) applying to the received single carrier signal at least a time domain digital filter that uses the IIR coefficients.

6. The method according to claim 5 , wherein said IIR coefficients are calculated in a single pass.

7. A system for enhancing reception of a single carrier signal, the single carrier signal including a periodic training signal and data; the periodic training signal includes N symbols and L symbols, wherein L<N that constitute either a start portion or an end portion of said N symbols; the system comprising:

(a) a first processor and associated transmitter configured, in respect of each training signal, to: duplicate said L symbols to the end portion of the training signal if said L symbols constitute a start portion, or otherwise, duplicate said L symbols to the start portion of the training signal if said L symbols constitute an end portion, so as to constitute a modified training signal having a duplicated extension; and transmit said single carrier signal; and

(b) a second processor and associated receiver configured to: receive said transmitted single carrier signal and in respect of each modified training signal applying signal processing operations that include:

(b1) calculation of FIR coefficients utilizing said modified training signal;

(b2) calculation of a residue signal using FIR with said FIR coefficients;

(b3) calculation of feedback coefficients (IIR) based on said residue; and

(b4) application of a time domain digital filter to the received single carrier signal, wherein the time domain digital filter is in accordance with the respective IIR coefficients and FIR coefficients.

8. The system according to claim 7 , wherein said processor includes FFT and IFFT modules configured to calculate the FIR coefficients.

9. The system of claim 8 , wherein said FIR coefficients and said IIR coefficients are calculated in a single pass.

10. The system according to claim 7 , wherein said processor includes FFT and IFFT modules configured to calculate the IIR coefficients.

11. The system according to claim 7 , wherein said single carrier being a VSB (ATSC) signal.

12. The system according to claim 11 , wherein the ATSC signal includes frames that are divided into 2 fields, an even field and an odd field; each field further being divided into 313 segments of 832 symbols each; the first segment in every field contains a modified training signal that consists of portions A through H, wherein

A—signifies 4 symbols segment sync;

B—signifies 511 symbols of a PN511 training signal;

C—signifies 63 symbols of a PN63 training signal;

D—signifies 63 symbols of a PN63 training signal having alternate polarity every field;

E—signifies 63 symbols of a PN63 training signal;

F—signifies 24 symbols VSB mode;

G—signifies 92 unused symbols;

H—signifies 12 symbols for trellis coding; and,

the other 312 segments each contain 4 segment sync symbols plus 828 symbols of data; wherein N=511 and L=305.

13. The system according to claim 11 , wherein said duplicated extension is the end portion.

14. The system according to claim 11 , wherein said first processor is configured to produce said modified training signal by applying a calculation that includes at least:

modifying the N symbols to a 2n length series;

duplicating L symbols (L<N) from among a start portion of the resulting modified N symbols, to the end portion of the training signal so as to give rise to a duplicated extension in a modified training signal; and,

repeating the modified training signal at a pre-determined rate inside the single carrier signal.

15. The system according to claim 7 , wherein said single carrier signal is a QAM signal.

16. The system according to claim 7 , wherein said duplicated extension is the end portion.