Parameter prediction for autonomous DSL system configuration profile selection

Patent metadata

Field	Value
Publication number	US-9042251-B2
Application number	US-201013638184-A
Country	US
Kind code	B2
Filing date	Apr 1, 2010
Priority date	Apr 1, 2010
Publication date	May 26, 2015
Grant date	May 26, 2015

Abstract

Method and arrangement for predicting a parameter indicative of an achievable bit rate when using a certain configuration in a digital subscriber line. The method involves obtaining basic configuration parameters of a known configuration; selecting a candidate configuration; and deriving an estimated parameter, indicative of an achievable bit rate, based on the obtained and selected parameters.

First claim

The invention claimed is:

1. A method for predicting a parameter indicative of an achievable bit rate when using a certain configuration in a digital subscriber line, the method comprising:
obtaining the following parameters, associated with a known configuration Ci: a Discrete Multi-Tone modulation (DMT) symbol size (Li), a Signal-to-Noise Ratio (SNR) margin, and a first Impulse Noise Protection (INP) parameter associated with a predefined coding gain value γc, where the SNR margin is one of a target SNR margin and an actual SNR margin, and the first INP parameter is one of (a) a minimum INP (INPmin_i) and (b) an actual INP (INPact_i);
selecting a new candidate configuration Ci+1 associated with a target SNR margin (γm_i+1) and a second INP parameter (INPmin_i+1), where the INPmin_i+1 value is associated with a predefined coding gain value γc_i+1;
and deriving an estimated parameter indicative of at least one of the DMT symbol size Li+1 and the achievable bit rate (Dr_i+1) based on: the obtained parameters, the target SNR margin γm_i+1 of the candidate configuration, and the coding gain value γc_i+1 associated with the second INP parameter INPmin_i+1 of the candidate configuration, thus enabling estimation of the achievable bit rate, Dr_i+1, of the candidate configuration, wherein
an estimated DMT symbol size L for a certain configuration is calculated based on the parameters: NSC, γc, γm, SNRk and Pe, where NSC is the number of subcarriers on the line, γc is the coding gain associated with the minimum or actual INP value of the configuration, γm is the target or actual SNR margin of the line, SNRk is the SNR for subcarrier no. k, and Pe is the desired bit error probability, and
the DMT symbol size L for a certain configuration is estimated as:

L
≅

(

NSC
-
1

)

×

log
2

⁡

(

γ
c

)

-

(

NSC
-
1

)

×

log
2

⁡

(

γ
m

)

+

log
2

⁡

(

∏

k
=
1

NSC
-
1

⁢

SNR
k

Γ
⁡

(
Pe
)

)

,

where
Γ(Pe) is the Shannon gap for the desired bit error probability Pe, and, wherein L should fall within the constraint:

L
≤

4
×
R
×
D

INP

m
⁢

⁢
i
⁢

⁢
n

where R is the redundancy per Forward Error Correction codeword, and D is the interleaver depth.

2. The method according to claim 1 , wherein the estimated parameter is one of the DMT symbol size Li+1 and the achievable bit rate, Dr_i+1.

3. The method according to claim 1 , wherein an estimated difference in DMT symbol size between a configuration Ci and a configuration Ci+1 is calculated based on the parameters NSC, γc_i, γc_i+1, γm_i and γm_i+1, where NSC is the number of subcarriers on the line, γc is the coding gain associated with the minimum or actual INP of a configuration, and γm is the target or actual SNR margin of the line for a configuration.

4. The method according to claim 1 , wherein a forward error correction (FEC) block length N, a redundancy R and an interleaver depth D of a candidate configuration profile are estimated by emulating modem behaviour by applying a heuristic process taking the DMT symbol length Li+1, INPmin and maxDelay as input, where the INPmin and maxDelay are obtained from the candidate configuration Ci+1.

5. The method according to claim 4 , wherein one goal of the heuristic process is set to minimizing the interleaver depth D.

6. The method according to claim 1 , wherein the method is used in a process of adapting a line configuration to current line conditions, wherein the method further comprises:
obtaining information concerning current line conditions, and
determining whether the candidate line configuration fulfils certain requirements for use as a next line configuration, based on at least one of a predicted DMT symbol length and a predicted achievable bit rate.

7. The method according to claim 6 , wherein the information concerning line conditions relates to at least one of current line conditions and historic line conditions.

8. The method according to claim 1 , further comprising:
ranking different candidate configurations, based on at least one of a predicted DMT symbol length and a predicted achievable bit rate.

9. The method according to claim 1 , further comprising the step of providing information concerning at least one suitable, in terms of predicted achievable bit rate, candidate configuration to a unit, which is to perform a line reconfiguration based on said information.

10. The method according to claim 1 , further comprising the step of sel

Assignees

• Berg Miguel
• Augusto Sales Dantas Ramide
• Cederholm Daniel
• Goncalves Glauco
• Guedino De Siqueira Rodolpho
• Perazzo Rabelo Rodrigo
• Sadok Djamel
• Ericsson Telefon Ab L M

Inventors

• Berg Miguel
• Augusto Sales Dantas Ramide
• Cederholm Daniel
• Goncalves Glauco
• Guedino De Siqueira Rodolpho
• Perazzo Rabelo Rodrigo
• Sadok Djamel

Classifications

• H04L43/04 Primary

  Processing captured monitoring data, e.g. for logfile generation · CPC title

• H04L1/0001 Primary

  Systems modifying transmission characteristics according to link quality, e.g. power backoff (adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04) · CPC title

• H04L47/10

  Flow control; Congestion control · CPC title

• H04L41/083

  for increasing network speed · CPC title

• H04L1/0007

  by modifying the frame length · CPC title