METHOD AND APPARATUS FOR CROSSTALK MANAGEMENT AMONG DIFFERENT VECTORED GROUPS
The present invention relates generally to data communications, and more particularly to techniques based on the G.fast protocol for managing operation around potentially degrading un-cancellable crosstalk among separate vector groups implemented in a single G.fast based box located at a network distribution point, referred to as a Distribution Point Unit (DPU). In embodiments, techniques according to the invention configure transmission of signals from the different vector groups so as to avoid or prevent transmission of signals, either in the frequency domain or time domain or a combination of the two, from causing severe degradation in performance due to un-cancelled crosstalk among the separate groups.
1 . A method of controlling communications by transceivers in a common distribution point unit (DPU), the method comprising:
configuring all of the transceivers to use a time division duplex (TDD) physical frame having a downstream set of discrete multitone (DMT) symbol periods and an upstream set of DMT symbol periods;
configuring first ones of the transceivers to transmit in a first portion of the downstream set of DMT symbol periods of the physical frame; and
configuring second ones of the transceivers to transmit in a second portion of the downstream set of DMT symbol periods of the physical frame,
wherein the first and second portions do not contain any common DMT symbol periods in the physical frame.
2 . A method according to claim 1 , wherein the first and second ones of the transceivers are in first and second separate vectored groups for performing crosstalk cancellation, respectively.
3 . A method according to claim 2 , wherein the all of the transceivers are coupled to loops contained in a common bundle, such that the common bundle contains two or more separate vectored groups for performing crosstalk cancellation.
4 . A method according to claim 1 , wherein configuring the first and second transceivers to transmit includes defining first and second different downstream logical frames, respectively, wherein the first and second different downstream logical frames both contain the same number of DMT symbol periods but are aligned in time at different positions within the physical frame.
5 . A method according to claim 4 , wherein defining the first and second different downstream logical frames includes defining first and second different positions of a robust management channel (RMC) symbol in the downstream set of DMT symbol periods.
6 . A method according to claim 4 , wherein defining the first and second different downstream logical frames includes defining a normal operation interval in both of the first and second different downstream logical frames and at least two different discontinuous operation sub-intervals in both of the first and second different downstream logical frames.
7 . A method according to claim 6 , wherein configuring the first and second transceivers to transmit includes configuring the first and second transceivers to transmit during the normal operation interval and in one or more of the two different discontinuous operation sub-intervals.
8 . A method according to claim 1 , wherein the communications are in accordance with G.fast.
9 . A distribution point unit (DPU) comprising:
a plurality of transceivers; and
a dynamic resource allocation (DRA) function, the DRA having circuitry adapted to:
configure all of the transceivers to use a time division duplex (TDD) physical frame having a downstream set of discrete multitone (DMT) symbol periods and an upstream set of DMT symbol periods;
configure first ones of the transceivers to transmit in a first portion of the downstream set of DMT symbol periods of the physical frame; and
configure second ones of the transceivers to transmit in a second portion of the downstream set of DMT symbol periods of the physical frame,
wherein the first and second portions do not contain any common DMT symbol periods in the physical frame.
10 . A DPU according to claim 9 , further comprising:
a first vector engine for performing crosstalk cancellation for the first transceivers; and
a second vector engine for performing crosstalk cancellation for the second transceivers, such that the common bundle contains two or more separate vectored groups for performing crosstalk cancellation.
11 . A DPU according to claim 10 , wherein the all of the transceivers are coupled to loops contained in a common bundle.
12 . A DPU according to claim 9 , wherein configuring the first and second transceivers to transmit includes defining first and second different downstream logical frames, respectively, wherein the first and second different downstream logical frames both contain the same number of DMT symbol periods but are aligned in time at different positions within the physical frame.
13 . A DPU according to claim 12 , wherein defining the first and second different downstream logical frames includes defining first and second different positions of a robust management channel (RMC) symbol in the downstream set of DMT symbol periods.
14 . A DPU according to claim 12 , wherein defining the first and second different downstream logical frames includes defining a normal operation interval in both of the first and second different downstream logical frames and at least two different discontinuous operation sub-intervals in both of the first and second different downstream logical frames.
15 . A DPU according to claim 14 , wherein configuring the first and second transceivers to transmit includes configuring the first and second transceivers to transmit during the normal operation interval and in one or more of the two different discontinuous operation sub-intervals.
16 . A DPU according to claim 9 , wherein the transceivers are G.fast transceivers.