Systems and Methods for G.Vector Initialization

1. A method of initializing a first joining Digital Subscriber Line (DSL) line and a second joining DSL line that are joining a first vectored DSL line group operating in Showtime, the method comprising: assigning a first super-periodic orthogonal pilot sequence to the first joining DSL line; assigning a second super-periodic orthogonal pilot sequence to the second joining DSL line, wherein the first and second super-periodic orthogonal pilot sequences have length L and are orthogonal over a segment of a pre-defined length T, wherein T<L; using the first and second super-periodic pilot sequences on the first and second joining DSL lines, respectively, to generate M sync-symbols worth of initialization data, wherein M>=T and M <L; and processing the generated initialization data to generate joining DSL line Far-End Crosstalk (FEXT) mitigation coefficients.

2. The method of claim 1 further comprising using the generated FEXT mitigation coefficients to operate the vectored DSL line group.

3. The method of claim 1 further comprising disabling FEXT mitigation coefficient updating in the first vectored DSL line group prior to using the first and second super-periodic pilot sequences to generate the initialization data.

4. The method of claim 1 further comprising disabling any online reconfiguration in the first vectored DSL line group prior to using the first and second super-periodic pilot sequences to generate the initialization data.

5. The method of claim 1 further comprising assigning a third super-periodic orthogonal pilot sequence to one or more DSL lines in the first vectored DSL line group prior to using the first and second super-periodic pilot sequences to generate the initialization data, wherein the first, second and third super-periodic orthogonal pilot sequences have length L and are orthogonal over length T<L.

6. The method of claim 5 further comprising reassigning Showtime orthogonal pilot sequences to DSL lines in a second vectored DSL line group comprising the first vectored DSL line group and the first and second joining DSL lines.

7. The method of claim 6 wherein the reassigned Showtime orthogonal pilot sequences are not super-periodic.

8. The method of claim 1 further comprising adjusting M to be greater than T to improve estimation error and/or Signal-to-Noise Ratio (SNR) degradation.

9. The method of claim 1 wherein L is 2 or a multiple of 4.

10. The method of claim 1 wherein T is 2 or a multiple of 4.

11. The method of claim 1 , wherein the using and processing steps are performed during a vector 1 phase of initialization according to G.vector.

12. The method of claim 1 wherein using the first and second super-periodic pilot sequences on the first and second joining DSL lines, respectively, to generate M sync-symbols worth of initialization data further comprises generating M=nT sync-symbols worth of initialization data, wherein n is an integer.

13. The method of claim 1 further comprising assigning a new pilot sequence to each Showtime line group line after completion of the joining DSL lines' joining the Showtime line group.

14. A vectoring control entity (VCE) configured to implement the method of claim 1 .

15. A method for initializing K joining Digital Subscriber Line (DSL) lines to determine Far-End Crosstalk (FEXT) coefficients as part of the joining DSL lines' joining a Showtime line group comprising a group of DSL lines running in Showtime as a vectored DSL group, the method comprising: assigning one orthogonal pilot sequence to each joining DSL line, wherein each orthogonal pilot sequence comprises a pilot sequence of length L from a subset of pilot sequences that are orthogonal to each other over a segment of a predefined length T, wherein T<L; stopping adaptation of FEXT mitigation coefficients for the Showtime line group; processing W sync-symbols worth of information, wherein W<L; estimating FEXT mitigation coefficients based on the processed sync-symbols information; using the estimated FEXT mitigation coefficients during operation of a vectored DSL group comprising the Showtime line group and the joining DSL lines.

16. The method of claim 15 wherein the method comprises at least part of a vector 1 phase under G.vector for adding new DSL lines to vectored DSL line group pursuant to G.vector.

17. The method of claim 15 further comprising disabling Online Reconfiguration (OLR) in the Showtime line group lines prior to processing W sync-symbols worth of information.

18. The method of claim 15 further comprising assigning at least one Showtime orthogonal pilot sequence from the pilot sequence subset to the Showtime line group lines, wherein the Showtime orthogonal pilot sequence is not an orthogonal pilot sequence assigned to one of the joining DSL lines.

19. The method of claim 18 further comprising assigning a new pilot sequence to each Showtime line group line after completion of vector- 1 phases of G.vector initialization.

20. The method of claim 15 , further comprising assigning a new pilot sequence to each Showtime line group line after completion of the joining DSL lines' joining the Showtime line group.