Receiver state estimation in a duty cycled radio

1. A method for receiver state estimation comprising:

(a) communicating, from a first communications device to a second communications device, a first plurality of wake-up frames;

(b) receiving, at the first communications device from the second communications device, an indication of a received wake-up frame of the communicated first plurality of wake-up frames;

(c) determining, by the first communications device, a time at which the second communications device is in a ready state based on the received indication;

(d) subsequently communicating, from the first communications device to the second communications device, a second plurality of wake-up frames;

(e) wherein the first plurality is greater than the second plurality, the reduction in number from the first plurality to the second plurality being based on the determined time at which the second communications device is in a ready state.

2. The method of claim 1 , wherein the first communications device and the second communications device each comprise a remote sensor node (RSN).

3. The method of claim 1 , wherein the wake-up frames comprise wake-up messages.

4. The method of claim 1 , wherein the wake-up frames of the second plurality of wake-up frames are numbered in descending order.

5. The method of claim 1 , wherein, after the numbering of the wake-up frames has descended to zero, a message is transmitted.

6. A method for receiver state estimation comprising:

(a) communicating, from a first communications device to a second communications device, a first plurality of wake-up frames;

(b) receiving, at the first communications device from the second communications device, an indication of a received wake-up frame of the communicated first plurality of wake-up frames;

(c) determining, by the first communications device, an offset time relative to a clock of the first communications device based on the received indication;

(d) subsequently communicating, from the first communications device to the second communications device, a second plurality of wake-up frames;

(e) wherein the first plurality is greater than the second plurality, the reduction in number from the first plurality to the second plurality being based on the determined offset time.

7. The method of claim 6 , wherein the first communications device and the second communications device each comprise a remote sensor node (RSN).

8. The method of claim 6 , further comprising the step of storing the offset time at the first communications device.

9. A system, comprising:

(a) a first communications device configured to communicate, to a second communications device, a first plurality of wake-up frames;

(b) a second communications device configured to, based upon receipt of one or more wake-up frames of the first plurality of wake-up frames, communicate an indication of a received wake-up frame to the first communications device;

(c) wherein the first communications device is further configured to

(i) determine a time at which the second communications device is in a ready state based on the communicated indication, and

(ii) subsequently communicate to the second communications device, a second plurality of wake-up frames;

(d) wherein the first plurality is greater than the second plurality, the reduction in number from the first plurality to the second plurality being based on the determined time at which the second communications device is in a ready state.

10. The system of claim 9 , wherein the first communications device and the second communications device each comprise a remote sensor node (RSN).