Method and apparatus for minimizing near end cross talk due to discrete multi-tone transmission in cable binders

• US 20010055332A1
• Filed: 01/26/2001
• Published: 12/27/2001
• Est. Priority Date: 02/17/2000
• Status: Active Grant

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Sonalkar, Ranjan V., Sadjadpour, Hamid R.
• Granted Patent: US 6,393,052 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04B 3/32 Reducing cross-talk, e.g. by compensating
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority

Abstract

In a discrete multi-tone modem, a method of minimizing cross talk over a twisted pair of a twisted pair cable binder in which discrete multi-tone data transmission is utilized comprises the steps of one of jointly minimizing near end cross talk while maximizing total data rate, jointly minimizing an arbitrary function of total power while maximizing total data rate and minimizing total near end cross talk for a given data rate, selecting a function to be optimized and performing a bit and power allocation algorithm responsive to the selected function. The process may be combined with known optimization functions such as jointly minimizing an average bit error rate while maximizing the data rate. As a result, the process is considerably more flexible and adaptable to changing parameters such as environmental parameters impacting data transmission performance in the presence of cross talk. Either a telecommunications central office modem or a remote terminal modem may be so adapted to apply such a cross talk minimization method.

Claims

1. In a discrete multi-tone modem, a method of minimizing cross talk over a twisted pair of a twisted pair cable binder, the method comprising the steps of:

one of jointly minimizing near end cross talk while maximizing total data rate;

jointly minimizing an arbitrary function of total power while maximizing total data rate and minimizing total near end cross talk for a given data rate;

selecting a function to be optimized; and

performing a bit and power allocation algorithm responsive to the selected function.

2. The method of

claim 1

further comprising the step of estimating settings for time and frequency domain equalizers.

3. The method of

claim 1

comprising the initial step of:

measuring a noise power spectral density of said twisted pair.

4. The method of

claim 1

wherein said twisted pair comprises a section of a hybrid fiber twisted pair channel between a central office telecommunications modem and a remote terminal modem.

5. The method of

claim 1

wherein said function selection step is responsive to one of a power minimization function, a joint average bit error rate minimization while maximizing data rare function, a maximizing data rate function and a joint power minimization and maximization of data rate function.

6. In a discrete multi-tone modem, apparatus for minimizing cross talk in a twisted pair, said apparatus comprising:

means for one of minimizing near end cross talk while maximizing total data rate, jointly minimizing an arbitrary function of total power while maximizing total data rate and minimizing total near end cross talk for a given data rate;

means for selecting a function to be optimized; and

means for performing a bit and power allocation algorithm responsive to the selected function.

7. The apparatus of

claim 6

further comprising means for estimating settings for time and frequency domain equalizers.

8. The apparatus of

claim 6

comprising means for initially measuring a noise power spectral density of said twisted pair.

9. The apparatus of

claim 6

wherein said twisted pair comprises a section of a hybrid fiber twisted pair channel between a central office telecommunications modem and a remote terminal modem.

10. The apparatus of

claim 6

wherein means for selecting a function is responsive to one of a power minimization function, a joint average bit error rate minimization while maximizing data rare function, a maximizing data rate function and a joint power minimization and maximization of data rate function.