2_OBA001009 ADSL Parameters in-Depth ISSUE1.0

7/29/2019 2_OBA001009 ADSL Parameters in-Depth ISSUE1.0

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HUAWEI TECHNOLOGIES CO., LTD. All rights reserved

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OBA001009 ADSL

Parameters In-depth

ISSUE 1.0


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HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page 1

Introduction

This course introduces various

parameters in the ADSL line profile

and guide the configuration of ADSL

services.


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Upon completion of this course, you will be

able to:

Master the meanings of all parameters

in the ADSL activation template

Master the method of selecting

parameters


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Chapter 1 ADSL Line profile

Chapter 2 ADSL Line Activation Parameters


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Adsl line-profile

Profi le index :1 Name: DEFVAL

ADSL transm issio n mode : All(G992.1~5,T1.413)

Trel l is mo de : Enable

Upstream channel bi t swap : Disable

Down stream channel bi t swap : Disable

Channel mode : Interleaved

Maximum dow nstream inter leaved delay(ms) : 6

Maximum upstream inter leaved delay(ms) : 6

Target dow nstream SNR margin(dB) : 6

Maximum acceptable dow nstream SNR margin(dB) : 31

Minimum acceptable downstream SNR margin(dB) : 0

Target ups tream SNR margin(dB ) : 6

Maximum acceptable ups tream SNR margin(dB) : 31


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Adsl line-profile

Minimum acceptable ups tream SNR margin(dB) : 0

Downs tream SNR margin for rate dow nsh i f t (dB ) : 0

Downs tream SNR margin for rate ups hi f t (dB) : 0

Upstream SNR margin for rate dow nsh i f t (dB) : 0

Upstream SNR margin for rate upsh i f t (dB ) : 0

Minimum upsh i f t t ime in dow nstream(secon ds) : 0

Min imum downs hi f t t ime in downst ream(seconds) : 0

Minimum upsh i f t t ime in ups tream(seconds ) : 0

Minimum downshi f t t ime in ups tream(seconds ) : 0

Downs tream Form of transm it rate adaptat ion : Adapt ing at star tup

Minimum transmit rate dow nstream(Kbps) : 32Maximum transmit rate dow nstream(Kbps) : 6144

Minimum transmit rate ups tream(Kbps ) : 32

Maximum transmit rate upstream(Kbps) : 640

-----------------------------------------------------------------------------


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ADSL transmission mode

ADSL transmission mode:

> 0: All (G992.1, G992.2, T1.413)

> 1: Full rate (G992.1 or T1.413)

> 2: G992.2(g.l i te) (ADLI bo ard doesn 't supp ort g.l i te operating mode)

> 3: T1.413 (ADL I bo ard doesn 't supp ort T1.413 operating mode)

> 4: G992.1 (g.dm t)

> 5: g.hs (G992.1 and G992.2, G992.1 is pr io r to G992.2)


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ADSL standards

Standard type Standard name Description

First generation

ADSL

G992.1,T1.413Full-rate ADSL, with downstream rate of up to

8 Mbit/s.

G992.2 (G.Lite) Splitterless ADSL, with downstream rate of upto 1.5 Mbit/s.

Second generation

ADSL

G992.3 (G.dmt.bis)ADSL2 standard, with downstream rate of up to

12 Mbit/s.

G992.4 (G.lite.bis) ADSL2 G.lite

G992.5 (G.dmt.bisplus)ADSL2+ standard, with downstream rate of up

to 24 Mbit/s.


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Trellis Coding

Achieve the best coding effect by special coding algorithms so

as to improve the SNR gain of the line. Practice shows that the

use of Trellis coding can improve the line SNR gain by at least

3 dB to 6 dB.

The line SNR value can be improved by 3 dB to 6 dB after

Trellis coding is used while the redundancy code used for error

control occupies the same line bandwidth.

> Trell is mode 0-disable 1-enable (0~1) [1]:


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Uplink/Downlink Bit Swapping

Function is to adjust bit distribution or power between sub-channels without deactivating the line.

> Downs tream channel bit swap 0-dis able 1-enable (0~1) [0]:

> Upstream channel bit swap 0-disable1-enab le (0~1) [0]:


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Channel Mode

Fast: Fast mode. It has general error correction capability but has little delay.

It is suitable for delay-sensitive services.

Interleaved: Interleaved mode. It has strong error correction capability.

However, the delay will increase as the error correction capability becomes

stronger with the increase of the interleave depth. This mode is suitable for

the services that require high reliability but are delay insensitive.

Please select channel mode 0-interleaved 1-fast (0~1) [0]:

Wil l you set inter leaved d elay? (y/n)[n] :y

Maximum downstream in ter leaved delay(0~255 ms) [6] :

Maximum upstream inter leaved delay(0~255 ms) [6] :


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Channel Mode

Interleaved

send receive

transmitinput output

output input


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Interleaving Principle

1234567

891011121314

15161718192021

Bit sequence(withoutinterleaving)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Bit sequence(with interleaving)

1 8 15 2 9 16 3 10 17 4 11 18 5 12 19 6 13 20 7 14 21

Burst error

Receive bit(withoutinterleaving)

1 2 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Receive bit(with interleaving)

1 3 4 5 6 7 8 10 11 12 13 14 16 17 18 19 20 21

1234567

891011121314

15161718192021

Write into FEC

Read in channel

Interleaving Process

Deinterleaving Process:

Write into channel

Read in FEC

DepthD=3

Span N=7

21654321

16921581

21654321


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Form of transmit rate

Fixed

It indicates that an ADSL port is activated at a fixed downstream rate. This

downstream rate must be equal to the maximum/minimum downstream rate to beset.

adaptAtStartup

It indicates that an ADSL connection is set up between an ADSL port and the

Modem at an optimal rate according to the auto-training result between them. This

rate shall be within the range from the maximum to the minimum rate to be set.

adaptAtRuntime

It indicates that the line rates are adjusted according to line conditions. When line

conditions deteriorate, the line rate will be reduced to boost ADSL connection

stability. When line conditions are good, the line rate will be boosted.

> Please select form of transm it rate adaptation in dow nstream:> 0-f ixed 1-adaptA tStartup 2-adaptA tRun time (0~2) [1]:


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SNR margin

SNR (Signal to Noise Ratio) margin refers to the level of noise that is tolerable without

deteriorating the current line rates and Bit Error Rate (BER).

The SNR margin for a Modem is proportional to ADSL connection stability. The largerthe SNR margin is, the higher the stability will be.

> Wil l you set SNR margin for modem? (y/n) [n] :

> Target SNR margin in down stream (0~15 dB ) [6] :

> Minim um SNR margin in downstream (0~6 dB ) [0] :

> Maximum SNR margin in downstream (6~31 dB ) [31]:> Target SNR margin in ups tream (0~15 dB ) [6]:

> Minim um SNR margin in ups tream (0~6 dB ) [0] :

> Maximum SNR margin in upstream (6~31 dB ) [31]:


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Rate parameters

The rate is closely related to the ADSL line stability. A too high rate maycause poor stability in an ADSL connection.

> Wil l you set parameters for rate? (y/n) [n] :y

> Minim um transm it rate in dow nstream (32~32000 Kbps) [32]:

> Maximum transm it rate in down stream (32~32000 Kbps) [24544]:

> Minim um transm it rate in up stream (32~3000 Kbps ) [32]:

> Maximum transm it rate in up stream (32~3000 Kbps ) [1024]:


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Chapter 1 ADSL Line profile

Chapter 2 ADSL Line Activation Parameters


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Uplink/Downlink Noise Margin

The SNR

taken up for

bit allocation

Current

noise

margin

SNRduring

training

Used to

allocate

bits

Target

noisemargin

SNRatacertain

practicalmoment

The SNR

taken up for

bit

allocation

Current noisemargin

SNRatacertain

practicalmoment

The noise margin has

become a complex valueThe noise margin

can still be tolerated


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Uplink/Downlink Rate

The maximum rate that can be activated varies for the interleaved mode

and the fast mode due to the different overheads and algorithms they

adopt. The downlink rate can be up to 8128 kbps for the fast mode while

it can be only up to 7616 kbps for the interleaved mode.

The uplink rate can be up to 896 kbps for both the interleaved mode andthe fast mode. These values all refer to the values measure din the

G.dmt and T1.413 modes.

In the G.lite mode, the maximum uplink rate is 512 kbps and the

maximum downlink rate is 1536 kbps.


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Maximum Uplink/Downlink Rate

The maximum attainable rate is only a calculation result


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Uplink/Downlink Attenuation

The attenuation of a line is decided by the core diameter,

length, conductorand media material feature of the line.


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Transmit Power

The transmit power refers to the signal power sent by the Modem (CO,

CPE) to the line.


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Summary Upon completion we learned:

Various parameters in the ADSLactivation template

Guide the configuration of ADSL

services.


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2_OBA001009 ADSL Parameters in-Depth ISSUE1.0