Undesirable energy suppression system in a contention based communication network

• US 5,745,836 A
• Filed: 02/08/1996
• Issued: 04/28/1998
• Est. Priority Date: 09/01/1995
• Status: Expired due to Fees

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Williams, Thomas H.
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): Miller, John W.
• Application Number:
  US08/598,333
• Time in Patent Office: 810 Days
• Field of Search: 348/5.5, 348/6, 348/7, 348/10, 348/11, 348/12, 348/13, 455/3.1, 455/4.1, 455/4.2, 455/5.1, 455/6.1, 455/6.2, 395/200.47-200.49
• US Class Current: 725/125
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

An undesirable energy suppression system in a contention based communications network having a shared communication path between a plurality of remote points and a headend in a simplex network or a bidirectional network. The system includes a method and apparatus for transmitting a signal on the shared communication path from any one of the plurality of remote points contending for the shared communication path, to the headend. The signal includes a gate enabling signal also known as a prybar signal. The shared communication path includes a gate where the gate connects the shared communication path when the gate is closed, and the gate disconnects the shared communication path when the gate is open. The system controls the gate in response to receiving the gate enabling signal. Absent a gate enabling signal, any signal or other energy on the shared communication path will not propagate through the network because the shared communication path is disconnected.

In one embodiment a single gate is located where it can serve an entire distribution branch of remote points in a tree and branch style network. In another embodiment there is a gate dedicated to each individual remote point in the network.

Claims

1. An undesirable energy suppression system in a contention based communication network wherein said contention based communications network includes a communication path between at least one remote point and a headend, said system comprising:

a gate means in said communication path wherein said gate means connects said communication path when said gate means is closed and said gate means disconnects said communication path when said gate means is open;

means for transmitting a signal on said communication path wherein said signal includes a gate enabling signal; and

means for closing said gate means only in response to said gate enabling signal.

2. A system according to claim 1 including:

a bidirectional communication path having a first direction for transmitting from said headend toward said at least one remote point and having a second direction for transmitting from said at least one remote point toward said headend;

means for transmitting a first signal in said first direction wherein said first signal includes a timing signal to synchronize said headend and said at least one remote point;

means responsive to said timing signal, for transmitting a second signal in said second direction on a designated time boundary wherein said second signal includes any one of a plurality of coded signals as said gate enabling signal such that only one of said plurality of coded signals uniquely corresponds to an individual one of said at least one remote point; and

means for closing said gate means in response to said gate enabling signal and said designated time boundary.

3. A system according to claim 1 including:

a bidirectional communication path having a first direction for transmitting from said headend toward said at least one remote point and having a second direction for transmitting from said at least one remote point toward said headend;

means for transmitting a first signal in said first direction wherein said first signal includes a status signal indicative of transmission activity in said second direction;

means responsive to said status signal, for transmitting a second signal in said second direction wherein said second signal includes said gate enabling signal; and

means for closing said gate means in response to said gate enabling signal and said status signal.

4. A system according to claim 3 including:

means for transmitting a first signal in said first direction wherein said first signal includes a timing signal to synchronize said headend and said at least one remote point;

means responsive to said timing signal and said status signal, for transmitting a second signal in said second direction on a designated time boundary when said second direction is clear, wherein said second signal includes said gate enabling signal; and

means for closing said gate means in response to said gate enabling signal and said status signal and said designated time boundary.

5. A system to prevent undesirable energy from propagating along a bidirectional communication path of a contention based communication network, wherein said bidirectional communication path includes a forward path from a headend signal source toward a plurality of remote points and a return path from said plurality of remote points toward said headend, and wherein said communication network includes a tree type trunk and distribution branch configuration, said system comprising:

a primary switch means on said return path of said bidirectional communication path;

at least one secondary switch means in said return path between said primary switch means and said headend;

means for assigning a unique coded switch enabling signal to each of said plurality of remote points;

means for validating said unique coded switch enabling signal associated with a transmitting one of said plurality of remote points; and

means, in response to validating said unique coded switch enabling signal, for enabling said primary switch means and said at least one secondary switch means to complete said return path and allow a transmission from a transmitting one of said plurality of remote points to pass.

6. A system according to claim 5 including:

means for removing said unique coded switch enabling signal from said transmission in said return path when each of said primary switch means and said at least one secondary switch means are enabled.

7. An undesirable energy suppression system in a contention based communications network wherein said contention based communications network includes a bidirectional communication path between a headend signal source and a plurality of remote points and wherein said bidirectional communication path includes a first direction from said headend toward said plurality of remote points and a second direction from said plurality of remote points toward said headend, said system comprising:

means for transmitting a first signal in said first direction of said bidirectional communication path wherein said first signal includes a status signal indicative of transmission activity in said second direction;

means responsive to said status signal, for transmitting a second signal in said second direction of said bidirectional communication path from any one of said plurality of remote points; and

means for controlling a return gate in said second direction of said bidirectional communication path at a time substantially concurrently with said second signal being transmitted in said second direction wherein said controlling means is responsive to said status signal and a gate enabling signal from a transmitting one of said plurality of remote points.

8. A system according to claim 7 wherein said system includes:

means for determining said status signal indicative of transmission activity in said second direction.

9. A system according to claim 7 wherein said means for transmitting said second signal includes:

means for transmitting said second signal in said second direction only when said status signal indicates said second direction is clear; and

means for retransmitting said second signal in said second direction after a delay when said status signal indicates said second direction is jammed.

10. A system according to claim 7 wherein said means for controlling includes:

means for assigning a gate enabling signal to each of said plurality of remote points;

means for transmitting said gate enabling signal by said transmitting one of said plurality of remote points substantially concurrently with said second signal transmitted in said second direction;

means for enabling said return gate to complete said second direction of said bidirectional communication path in response to said gate enabling signal from said transmitting one of said plurality of remote points and in response to said status signal indicating said second direction is clear; and

means for disabling said return gate to disconnect said second direction of said bidirectional communication path in response to said status signal indicating said second direction is not busy.

11. A system according to claim 10 including:

means for assigning said gate enabling signal wherein said gate enabling signal is shared by at least two of said plurality of remote points.

12. A system according to claim 10 including:

means for assigning said gate enabling signal wherein said gate enabling signal is unique for each of said plurality of remote points.

13. A system according to claim 10 including:

means for removing said gate enabling signal from said second signal after enabling said return gate.

14. A system according to claim 7 including:

means for serving a subset of said plurality of remote points on a distribution branch of said network by way of a single return gate.

15. A system according to claim 7 including:

means for serving said plurality of remote points in said network by way of a plurality of return gates each dedicated to a corresponding one of said plurality of remote points in said network.

16. A system according to claim 15 including:

means for disconnecting an individual one of said plurality of remote points from said first direction of said bidirectional communication path; and

means for reconnecting said individual one of said plurality of remote points to said first direction of said bidirectional communication path.

17. A system according to claim 15 including:

means for interdicting said bidirectional communication path at a location proximate to each of said plurality of return gates.

18. A method for suppressing undesirable energy in a contention based communications network wherein said contention based communications network includes a bidirectional communication path between a headend signal source and a plurality of remote points and wherein said bidirectional communication path includes a first direction from said headend toward said plurality of remote points and a second direction from said plurality of remote points toward said headend, said system comprising:

transmitting a first signal in said first direction of said bidirectional communication path wherein said first signal includes a status signal indicative of transmission activity in said second direction;

transmitting a second signal in said second direction of said bidirectional communication path from any one of said plurality of remote points in response to said status signal; and

controlling a return gate in said second direction of said bidirectional communication path at a time substantially concurrently with said second signal being transmitted in said second direction wherein said controlling step is responsive to said status signal and a gate enabling signal from a transmitting one of said plurality of remote points.

19. A method according to claim 18 including:

determining said status signal indicative of transmission activity in said second direction.

20. A method according to claim 18 wherein said step of transmitting said second signal includes:

transmitting said second signal in said second direction only when said status signal indicates said second direction is clear; and

retransmitting said second signal in said second direction after a delay when said status signal indicates said second direction is jammed.

21. A method according to claim 18 wherein said controlling step includes:

assigning a gate enabling signal to each of said plurality of remote points;

transmitting said gate enabling signal by said transmitting one of said plurality of remote points substantially concurrently with said second signal transmitted in said second direction;

enabling said return gate to complete said second direction of said bidirectional communication path in response to said gate enabling signal from said transmitting one of said plurality of remote points and in response to said status signal indicating said second direction is clear; and

disabling said return gate to disconnect said second direction of said bidirectional communication path in response to said status signal indicating said second direction is not busy.

22. A method according to claim 21 including:

assigning said gate enabling signal wherein said gate enabling signal is shared by at least two of said plurality of remote points.

23. A method according to claim 21 including:

assigning said gate enabling signal wherein said gate enabling signal is unique to each of said plurality of remote points.

24. A method according to claim 21 including:

removing said gate enabling signal from said second signal after enabling said return gate.

25. A method according to claim 18 including:

serving a subset of said plurality of remote points on a distribution branch of said network by way of a single return gate.

26. A method according to claim 18 including:

serving said plurality of remote points in said network by way of a plurality of return gates each dedicated to a corresponding one of said plurality of remote points in said network.

27. A method according to claim 26 including:

disconnecting an individual one of said plurality of remote points from said first direction of said bidirectional communication path; and

reconnecting said individual one of said plurality of remote points to said first direction of said bidirectional communication path.

28. A method according to claim 26 including:

interdicting said bidirectional communication path at a location proximate to each of said plurality of return gates.

29. A method for suppressing undesirable energy in a contention based communications network having a bidirectional communication path between a headend signal source and a plurality of remote points wherein said bidirectional communication path includes a first direction from said headend toward said plurality of remote points and a second direction from said plurality of remote points toward said headend, said method comprising:

determining transmission activity in said second direction and generating a status signal representing said transmission activity;

transmitting a first signal in said first direction of said bidirectional communication path wherein said first signal includes said status signal;

transmitting a second signal in said second direction of said bidirectional communication path from any one of said plurality of remote points only when said status signal indicates said second direction is clear; and

enabling a return gate in said second direction of said bidirectional communication path at a time substantially concurrently with said second signal being transmitted in said second direction wherein said return gate connects said second direction when said status signal indicates that said second direction is clear and in response to said gate enabling signal from a transmitting one of said plurality of remote points.

30. A method according to claim 29 wherein said gate enabling signal is shared among at least one subset of said plurality of remote points.

31. A method according to claim 29 wherein said gate enabling signal is unique to each of said plurality of remote points.