Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Impulse noise management

Impulse noise management description/claims

This application claims the benefit of and priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60/549,804, entitled “On-Line Impulse Noise Protection (INP) Adaptation,” filed Mar. 3, 2004, and U.S. Provisional Application No. 60/555,982, entitled “Impulse Noise Protection (INP) Training,” filed Mar. 24, 2004, both of which are incorporated herein by reference in their entirety.

1. Field of the Invention

This invention generally relates to communication systems. In particular, an exemplary aspect of this invention relates to impulse noise protection adaptation. Another exemplary aspect of this invention relates to impulse noise length and period determination and use thereof for impulse noise protection adaptation.

2. Description of Related Art

Communications systems often operate in environments that produce impulse noise. Impulse noise is a short-term burst of noise that is higher than the normal noise that typically exists in a communication channel. For example, DSL systems operate on telephone lines and experience impulse noise from many external sources including telephones, AM radio, HAM radio, other DSL services on the same line or in the same bundle, other equipment in the home, etc. It is standard practice for communications systems to use interleaving in combination with Forward Error Correction (FEC) to correct the errors caused by impulse noise. Standard initialization procedures in ADSL and VDSL systems are designed to optimize performance (data rate/reach) in the presence “stationary” crosstalk or noise. Impulse noise protection is handled with interleaving and FEC, but the current xDSL procedure at least does not provide specific states to enable training for the selection of the appropriate interleaving and FEC parameters.

An exemplary problem associated with traditional communication systems is that they use traditional Signal to Noise Ratio (SNR) measurement techniques to determine the SNR of the channel. These traditional techniques assume that the noise is stationary and does not contain non-stationary components such as impulse noise. The most common method for measuring the SNR is to calculate the mean-square error of the received signal based on a known transmitted signal, which is described in the ADSL series of ITU G.992.x standards and the VDSL series of ITU G.993.x standards, which are incorporated herein by reference in their entirety. These traditional methods for measuring SNR do not correctly measure the impact of impulse noise and do not have the noise capability to determine how the system should be configured to handle impulse noise.

There has been proposed that there is a need in ADSL and VDSL systems to provide robust error-free performance in the presence of high, real-world impulse noise. A specific proposal recommends that the standard impulse noise protection (IP) values are extended to values of 4, 8, 16 and 32 in order to handle high levels of impulse noise. Impulse noise protection is defined in the ADSL2 Standard G.992.3, which is incorporated herein by reference in its entirety, as the number of impulse noise corrupted DMT symbols that can be corrected by the FEC and interleaving configuration. Specifically, G.992.3 defines the following variables:

INP=½*(S*D)*R/N

S=8*N/L

Latency (or delay)=S*D/4

• Provisional Patent
• Utility Patent

• What Is a Patent?
• What Is a Trademark or Servicemark?
• What Is a Copyright?
• Patent Laws