Method and apparatus for power tuning a terminal of a bi-directional communications system

• US 6,111,887 A
• Filed: 10/08/1997
• Issued: 08/29/2000
• Est. Priority Date: 10/08/1997
• Status: Expired due to Fees

• Current Assignee: Zenith Electronics Corporation (LG Corporation)
• Original Assignee: Zenith Electronics Corporation (LG Corporation)
• Inventors: Johnson, Thomas M., Pennacchia, Thomas E., Daily, Mack S.
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): NGUYEN, BRIAN D
• Application Number:
  US08/947,038
• Time in Patent Office: 1,056 Days
• Field of Search: 370/449, 370/422, 370/345, 370/346, 370/241, 370/245, 370/312, 370/404, 370/431, 370/432, 455/5.1, 455/4.1, 455/68, 455/69, 455/77, 340/825.06, 340/825.07, 340/825.08
• US Class Current: 370/449
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6377 directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 7/17354 in an intermediate station common to a plurality of user terminals
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range

Abstract

A method and apparatus for power tuning a terminal of a bi-directional communications system, such as a cable television plant. An iterative or cycle method is used to achieve a proper terminal transmitter power level at a remote terminal. A polling signal is transmitted in a downstream direction from a controller to the terminal. If the controller receives a status signal which is transmitted upstream from the terminal, then the controller compares a received power level measured at a head end against a predetermined range of acceptable power levels. If the power level is outside of the predetermined range, then the controller calculates and transmits a terminal transmitter power level in a downstream direction to the terminal. The iterative or cyclic method repeats until the received power level is within the predetermined range. If the received power level of the terminal remains outside of the predetermined range after a specified count of cycles or iterations or if the head end does not receive a status signal, then the controller either aborts the cycle or attempts to revive the terminal.

Claims

1. A method for power tuning a terminal of a bi-directional communications system, an iteration of the method comprising:

(a) transmitting a polling signal in a downstream direction from a controller to the terminal;

(b) receiving in the controller a status signal transmitted upstream from the terminal, comparing a received power level of the status signal against a predetermined signal range; and

(c) if the received power level is outside of the predetermined signal range, calculating a new terminal transmitter power level and transmitting the new terminal transmitter power level in the downstream direction to the terminal.

2. The method according to claim 1 wherein a head end transmits the polling signal.

3. The method according to claim 1 wherein the terminal is located remote with respect to the head end.

4. The method according to claim 1 wherein the received power level is measured at the head end.

5. The method according to claim 1 wherein the terminal transmitter power level is calculated as a function of at least one of a minimum power tune level of the predetermined signal range, a maximum power tune level of the predetermined signal range, a received power level measured at the controller, an incremental power level step, and the old terminal transmitter power level.

6. The method according to claim 5 wherein the function is equal to the old terminal transmitter power level plus a quantity equal to a difference between an average power level at a midpoint between the minimum power tune level and the maximum power tune level and the power level measured at the controller divided by the incremental power level step.

7. The method according to claim 1 wherein if the controller fails to receive the status signal a silent count of the polling signal is incremented to form an incremented polling signal, and a cycle is repeated with the incremented polling signal.

8. The method according to claim 7 wherein if the silent count reaches a maximum value the controller attempts to revive the terminal.

9. The method according to claim 8 wherein reviving the terminal comprises transmitting at least one terminal transmitter power level signal to the terminal until the controller receives the status signal transmitted from the terminal.

10. The method according to claim 9 wherein if the controller receives the status signal from the terminal a cycle is repeated.

11. The method according to claim 9 wherein if all of the terminal transmitter power level signals in the signal range are transmitted to the terminal and the controller fails to receive the status signal, a fault signal identifying a fault of the terminal is determined by the controller.

12. A method for power tuning a terminal of a bi-directional communications system, an iteration of the method comprising:

(a) transmitting a polling signal in a downstream direction from a controller to the terminal;

(b) receiving in the controller a status signal transmitted upstream from the terminal, comparing a received power level of the status signal against a predetermined signal range; and

(c) if the received power level is outside of the predetermined signal range, determining a new terminal transmitter power level and transmitting the new terminal transmitter power level in the downstream direction to the terminal; and

(d) wherein the terminal transmitter power level is determined as a function of at least one of a minimum power tune level of the predetermined signal range, a maximum power tune level of the predetermined signal range, a received power level measured at the controller, an incremental power level step, and the received old terminal transmitter power level; and

(e) wherein the function is equal to the old terminal transmitter power level plus a quantity equal to a difference between an average power level at a midpoint between the minimum power tune level and the maximum power tune level and the power level measured at the controller divided by the incremental power level step.

13. A method for power tuning a terminal of a bi-directional communications system, an iteration of the method comprising:

(a) transmitting a polling signal in a downstream direction from a controller to the terminal;

(b) receiving in the controller a status signal transmitted upstream from the terminal, comparing a received power level of the status signal against a predetermined signal range; and

(c) if the received power level is outside of the predetermined signal range, determining a new terminal transmitter power level and transmitting the new terminal transmitter power level in the downstream direction to the terminal; and

(d) wherein if the controller fails to receive the status signal a silent count of the polling signal is incremented to form an incremented polling signal, and a cycle is repeated with the incremented polling signal; and

(e) wherein if the silent count reaches a maximum value the controller attempts to revive the terminal; and

(f) wherein reviving the terminal comprises transmitting at least one terminal transmitter power level signal to the terminal until the controller receives the status signal transmitted from the terminal; and

(g) wherein if all of the terminal transmitter power level signals in the signal range are transmitted to the terminal and the controller fails to receive the status signal, a fault signal identifying a fault of the terminal is determined by the controller.