Vectoring. Downstream or also upstream?

Will it just improve downstream sync, or will it help upstream as well?

I assume it is transmitter end driven and only on downstream. Or will it be smart enough to cancel crosstalk on upstream too?

It works in both directions.

In reply to a post by RobertoS:

Will it just improve downstream sync, or will it help upstream as well?

I assume it is transmitter end driven and only on downstream. Or will it be smart enough to cancel crosstalk on upstream too?

The DSLAM pre-equalises the downstream, it applies noise cancellation before transmitting, and post-equalises the upstream, applies noise cancellation after receiving the signal.

Upstream is actually easier than down - on downstream the DSLAM has to rely on telemetry from the modems for information on disturbers as they see the crosstalk / noise on the received signal, while on upstream it has no need as it sees the result of noise + signal.

A brilliant short explanation. Thanks .

One of those things that are obvious once you know, and totally opaque when you don't!

But....vectoring isn't available for us all at the moment?

In reply to a post by RobertoS:

A brilliant short explanation. Thanks .

One of those things that are obvious once you know, and totally opaque when you don't!

You're very welcome. The first reply came when I was in the middle of a work call, waiting for customer and killing time, hence the brevity. Had more time for the second

Neither are a lot of things; doesn't mean we can't be curious about how they work.

Edited by deleted (Fri 31-Jul-15 12:00:19)

The reason was this PN Community post, and my reply on the next page.

I can't say BT won't deploy vectoring en masse, I can say that they've given no indication of any intent to do so and the business case gets more and more marginal with every passing week.

The only intent they've shown so far is to deploy vectoring largely in areas upgraded under BDUK where it would help them hit the coverage targets they've agreed with local authorities.

Edited by deleted (Fri 31-Jul-15 23:23:43)