Method for transferring information using modems

• US 5,394,392 A
• Filed: 12/14/1992
• Issued: 02/28/1995
• Est. Priority Date: 12/14/1992
• Status: Expired due to Fees

• Current Assignee: Paradyne Corporation (Dasan Networks Incorporated)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Scott, Robert E.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): FOURNIER, PAUL
• Application Number:
  US07/990,159
• Time in Patent Office: 806 Days
• Field of Search: 379/93, 379/406, 379/410, 375/8, 375/121, 370/32, 370/32.1, 370/24, 370/27, 370/32, 370/29
• US Class Current: 370/295
• CPC Class Codes: H04B 3/20 Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
• CPC Class Codes: H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers

Abstract

A modem'"'"'s data reception rate is increased by decreasing the amplitude of the signals transmitted by the modem. Decreasing the amplitude of the transmitted signals reduces the amplitude of the resulting echoes, and thereby reduces the residual echoes that remain after echo cancellation. Reducing the residual echoes permits increasing the data reception rate. Decreasing the amplitude of the transmitted signals also involves decreasing the data transmission rate; however, asymmetrical data transfer rates are acceptable for many modem applications.

Claims

1. A method for transferring information between communication devices, over a communication channel having a near end and a far end, said method, comprising the steps of:

transmitting a first plurality of symbols from the near end of the communication channel to the far end of the communication channel with a first average signal level at the near end of the communication channel;

receiving a second plurality of symbols at the near end of the communication channel that are transmitted from the far end of the communication channel with a second average signal level at the far end of the communication channel, said second average signal level being substantially higher than said first average signal level;

using overlapping portions of the communications channel'"'"'s bandwidth for transmitting and receiving symbols; and

at least one of said communication devices monitoring a backlog of information to be transmitted and changing said first and second average signal levels when said backlog crosses a threshold.

2. The method of claim 1 wherein the step of monitoring a backlog of information to be transmitted comprises changing said first and second average signal levels so that said first average signal level is substantially higher than said second average signal level.

3. A method for transferring information between modems, over a communication channel having a near end and a far end, said method comprising the steps of:

transmitting a first plurality of symbols from the near end of the communication channel to the far end of the communication channel with a first average signal level at the near end of the communication channel;

receiving a second plurality of symbols at the near end of the communication channel that are transmitted from the far end of the communication channel with a second average signal level at the far end of the communication channel, said second average signal level being substantially higher than said first average signal level;

using overlapping portions of the communications channel'"'"'s bandwidth for transmitting and receiving symbols; and

at least one of said modems monitoring a backlog of information to be transmitted and changing said first and second average signal levels when said backlog crosses a threshold.

4. The method of claim 3 wherein the step of monitoring a backlog of information to be transmitted comprises changing said first and second average signal levels so that said first average signal level is substantially higher than said second average signal level.

5. The method of claim 3, further comprising the step of adding a tone to said first plurality of symbols.

6. A method for transferring information between modems, over a communication channel having a near end and a far end, said method comprising the steps of:

transmitting a first plurality of symbols from the near end of the communication channel to the far end of the communication channel with a first average signal level at the near end of the communication channel;

receiving a second plurality of symbols at the near end of the communication channel that are transmitted from the far end of the communication channel with a second average signal level at the far end of the communication channel, said second average signal level being substantially higher than said first average signal level;

using the same portions of the communication channel'"'"'s bandwidth for transmitting and receiving symbols; and

at least one of said modems monitoring a backlog of information to be transmitted and changing said first and second average signal levels when said backlog crosses a threshold.

7. The method of claim 6 wherein the step of monitoring a backlog of information to be transmitted comprises changing said first and second average signal levels so that said first average signal level is substantially higher than said second average signal level.

8. The method of claim 6, further comprising the step of adding a tone to said first plurality of symbols.