Adjustment of transmit power based on an estimated electrical length of a loop

In a digital subscriber line (DSL) system, a method for adjusting transmit power of a DSL modem based on an estimated electrical length of a loop, the method comprises:

• estimating an electrical length of a loop for each of a plurality signals based on a known power level of the plurality of signals, a known frequency for each of the plurality of signals, and a received power level for each of the plurality of signals;
• processing the plurality of estimated electrical lengths in accordance with a function corresponding to characteristics of the loop to produce a determined electrical length;
• and
• adjusting the transmit power of the DSL modem coupled to the loop based on the determined electrical length.

A digital subscriber line (DSL) system comprises:

• a first DSL modem at a first location operable to transmit a plurality of signals to a second DSL modem at a second location, wherein each signal of the plurality of signals has a known frequency and is transmitted at a known power level;
• the second DSL modem including means for determining received power level for each signal of the plurality of signals as the signal is received;
• the second DSL modem including means for estimating an electrical length of a loop between the first and second DSL modems for each of the plurality signals received from the first DSL modem to produce a plurality of estimated electrical lengths;
• the second DSL modem including means for processing the plurality of estimated electrical lengths in accordance with a function corresponding to characteristics of the loop between the first and second DSL modems to produce a determined electrical length;
• the second DSL modem operable to adjust the transmit power of the second DSL modem based on the determined electrical length.

An apparatus for estimating electrical length of a loop in a digital subscriber line (DSL) system, the apparatus comprises:

• means for estimating an electrical length of a loop for each of a plurality signals based on a known power level of the plurality of signals, a known frequency for each of the plurality of signals, and a received power level for each of the plurality of signals;
• and
• means for processing the plurality of estimated electrical lengths to produce a determined electrical length by establishing a weighting factor for each of the plurality of estimated electrical lengths such that lower valued estimated electrical lengths of the plurality of estimated electrical lengths have a greater weighting factor than higher valued estimated electrical lengths of the plurality of estimated electrical lengths to produce a plurality of weighted estimated electrical lengths, and computing the determined electrical length as at least one of:
• an average, a root mean square, and a least mean square of the plurality of weighted estimated electrical lengths.

In a digital subscriber line (DSL) system, an apparatus for adjusting transmit power of a DSL modem based on an estimated electrical length of a loop, the apparatus comprises:

• means for estimating an electrical length of a loop for each of a plurality signals based on a known power level of the plurality of signals, a known frequency for each of the plurality of signals, and a received power level for each of the plurality of signals;
• means for processing the plurality of estimated electrical lengths in accordance with a function corresponding to characteristics of the loop to produce a determined electrical length;
• and
• means for adjusting transmit power of a DSL modem coupled to the loop based on the determined electrical length.