LEADER-FOLLOWER POWER CONTROL

• US 20060270442A1
• Filed: 08/07/2006
• Published: 11/30/2006
• Est. Priority Date: 07/30/2004
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Miller, Mark J., O'Neill, John H.
• Granted Patent: US 7,580,673 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks

Abstract

In a satellite or other relayed communication system having a plurality of subscriber terminals that communicate through an elevated wireless relay (typically a satellite operating in bent pipe mode), a technique for subscriber terminal power control is provided whereby the power level is controlled via leader-follower operation relying on sharing control factors determined at a single calibrated subscriber terminal transmitter (the leader terminal) to create traffic to be compared to the received traffic of the other subscriber terminals. The power level of the subscriber terminals is then adjusted based on the relationship of their received energy to the received energy of the leader terminal.

Claims

1. In a relayed communication system having a hub and a plurality of subscriber terminals coupled for communication with one another via an elevated wireless relay operative in a bent pipe mode through a forward uplink path from the hub, a forward downlink path to the subscriber terminals, a return uplink path from the subscriber terminals, and a return downlink path to the hub, a method for transmit power level control at the subscriber terminals comprising:

providing a calibrated transmit signal terminal operative as a leader terminal and having a leader uplink from the leader terminal and a leader downlink to the hub so that the leader terminal experiences a downlink propagation path that approximates all subscriber terminal downlink propagation paths;

causing the leader terminal to calibrate its power level using power levels of its leader uplink and leader downlink;

generating leader testing signals at the leader terminal via the leader uplink;

generating subscriber testing signals at the subscriber terminals via the subscriber uplink;

estimating leader terminal power level received at the hub;

comparing the respective subscriber terminal power levels with the leader terminal power level to produce an error signal; and

using the error signal to produce a control signal to control the transmit power level of the subscriber terminals.

2. The method according to claim 1 wherein the comparing step is operative at the hub.

3. The method according to claim 2 wherein the hub communicates at least one of an error signal and a control signal to the subscriber terminals.

4. The method according to claim 1 wherein the comparing step is performed at each subscriber terminal.

5. The method according to claim 4 wherein the hub communicates the leader terminal power level estimate and a measured specific subscriber terminal power level to each corresponding specific subscriber terminal.

6. The method according to claim 5 wherein the error signal using step is performed at the subscriber terminal.

7. The method according to claim 5 wherein the communicating of the leader terminal power level estimate to the other subscriber terminals is via traffic through the forward downlink.

8. The method according to claim 1 wherein the leader terminal is collocated with the hub.

9. The method according to claim 1 wherein the leader terminal is remotely located away from the hub.

10. The method according to claim 1 wherein the subscriber testing signals comprise burst signals of dummy data from the subscriber terminals.

11. The method according to claim 10 wherein the dummy data is encoded with an error detection code.

12. The method according to claim 1 wherein the subscriber testing signals comprise normal message traffic from the subscriber terminals.