1. (canceled)
2. A symmetric transmit opportunity (TXOP) truncation method comprising:
receiving a first frame at a first station that truncates a TXOP around a second station that transmitted the first frame;
determining an estimated distance between the first station and the second station based on one or more characteristics of the received first frame; and
responsive to a determination that the coverage areas for both the first station and the second station do not substantially overlap, sending a second frame from the first station that truncates the TXOP around the first station.
3. The method of claim 2, further comprising sending an acknowledgement (ACK) frame before sending the second frame.
4. The method of claim 2, wherein the first frame is sent at a non-basic rate, and the second frame is sent at a basic rate.
5. The method of claim 2, wherein sending the second frame comprises sending the first frame with an address of an access point (AP).
6. The method of claim 5, wherein the address of the AP comprises an address in a BSSID field of the first frame.
7. The method of claim 2, wherein the first frame is a CF-end frame.
8. The method of claim 2, further comprising sending a frame that includes an indicator of an end of a TXOP.
9. The method of claim 9, wherein the indicator is a trigger to truncate the TXOP.
10. A symmetric transmit opportunity (TXOP) truncation station comprising a processor configured to:
receive a frame that truncates a TXOP around a first station that transmitted the frame;
determine an estimated distance between the second station and the first station based on one or more characteristics of the received frame; and
responsive to a determination that the coverage areas for both the first station and second station do not substantially overlap, send a second frame from the second station that truncates the TXOP around the second station.
11. The station of claim 10, wherein the processor is further configured to send an acknowledgement (ACK) frame before sending the second frame.
12. The station of claim 10, wherein the first frame is sent at a non-basic rate, and the second frame is sent at a basic rate.
13. The station of claim 10, wherein the processor is further configured to send the second frame by sending the first frame with an address of an access point (AP).
14. The station of claim 13, wherein the address of the AP comprises an address in a BSSID field of the first frame.
15. The station of claim 10, wherein the first frame is a CF-end frame.
16. A non-transitory, computer-readable medium having instructions stored there-on for performing a symmetric transmit opportunity (TXOP) truncation between a first station and a second station, the instructions comprising:
instructions for receiving a first frame at a first station that truncates a TXOP around a second station that transmitted the first frame;
instructions for determining an estimated distance between the first station and the second station based on one or more characteristics of the received first frame; and
instructions for sending a second frame from the first station that truncates the TXOP around the first station responsive to a determination that the coverage areas for both the first station and the second station do not substantially overlap.
17. The computer-readable medium of claim 16, further comprising instructions for sending an acknowledgement (ACK) frame before sending the second frame.
18. The computer-readable medium of claim 16, wherein the first frame is sent at a non-basic rate, and the second frame is sent at a basic rate.
19. The computer-readable medium of claim 16, wherein sending the second frame comprises sending the first frame with an address of an access point (AP).
20. The computer-readable medium of claim 19, wherein the address of the AP comprises an address in a BSSID field of the first frame.
21. The computer-readable medium of claim 16, wherein the first frame is a CF-end frame.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A vision prosthesis comprising:
an intra-ocular lens system having a focal length that varies in response to a change in an index of refraction, the intra-ocular lens system comprising a lens element with no moving parts;
a controller for causing a change in the focal length, the extent of the change being dependent on an estimate of a distance to an object of regard;
a first actuator for changing an index of refraction of the intra-ocular lens system in response to a signal from the controller; and
a second actuator for mechanically changing the focal length of the intra-ocular lens system in response to a signal from the controller.
2. The vision prosthesis of claim 1, further comprising a rangefinder for providing the controller with an estimate of a distance to an object-of-regard.
3. The vision prosthesis of claim 1, wherein the intra-ocular lens system comprises a chamber containing nematic liquid crystal.
4. The vision prosthesis of claim 1, wherein the intra-ocular lens system further comprises:
an additional lens element moveable relative to the lens element with no moving parts; and
wherein the second actuator comprises a motor coupled to the additional lens element for moving the additional lens element relative to the lens element with no moving parts.
5. The vision prosthesis of claim 2, further comprising a transducer for detecting a stimulus from an anatomic structure within the eye and providing a signal indicative of the stimulus to the rangefinder.
6. The vision prosthesis of claim 4, further comprising a manual focusing control for enabling a patient to fine tune focusing of the lens.
7. The vision prosthesis of claim 1, wherein the second actuator includes a micromechanical motor.
8. A vision-prosthesis comprising:
an intra-ocular lens system having a focal length that varies in response to a change in an index of refraction, the intra-ocular lens system comprising a lens element with no moving parts and a first actuator for changing an index of refraction of the intra-ocular lens system; and
a second actuator coupled to the intra-ocular lens system for mechanically causing a change in the focal length thereof, the extent of the change being dependent on an estimate of the distance to an object of regard.
9. The vision prosthesis of claim 8, further comprising a controller coupled to the second actuator for causing the second actuator to cause the change in the focal length.
10. The vision prosthesis of claim 8, further comprising a rangefinder for providing an estimate of a distance to an object of regard, the estimate forming a basis for determining an extent to which to vary the focal length.
11. The vision prosthesis of claim 8, further comprising a transducer for coupling to an anatomic structure within the eye, the transducer generating a signal indicative of a distance to an object-of-regard, the signal providing information to be used in determining an extent to which to vary the focal length.
12. The vision prosthesis of claim 8, wherein the second actuator includes a micromechanical motor.
13. A vision prosthesis comprising:
an intra-ocular lens system having a focal length that varies in response to a change in an index of refraction, the intra-ocular lens system comprising a lens element with no moving parts;
a first actuator for changing an index of refraction of the intra-ocular lens system;
a second actuator coupled to the intra-ocular lens system for mechanically causing a change in the focal length; and
a rangefinder for providing an estimate of an extent to which to vary the focal length.
14. The vision prosthesis of claim 13, wherein the rangefinder is configured to provide an estimate at least in part on the basis of activity of an anatomic structure within the eye.
15. The vision prosthesis of claim 14, further comprising a transducer configured to be coupled to the anatomic structure and to the rangefinder for providing the rangefinder with information indicative of activity of the anatomic structure.
16. The vision prosthesis of claim 13, further comprising a controller for receiving information from the rangefinder and causing a change to the focal length of the intra-ocular lens system at least in part on the basis of the information.
17. The vision prosthesis of claim 13, wherein the second actuator includes a micromechanical motor.
18. An apparatus comprising:
an intraocular lens having an index of refraction that varies in response to a focusing stimulus, the intraocular lens comprising a lens element with no moving parts;
a first actuator in communication with the intraocular lens for providing the focusing stimulus;
a second actuator coupled to the intra-ocular lens for mechanically causing a change in the focal length;
a rangefinder for generating a range estimate indicative of a relative distance to an object-of-regard; and
a controller coupled to the rangefinder and to the actuator for causing the actuator to generate a focusing stimulus on the basis of the range estimate.
19. The apparatus of claim 18, wherein the rangefinder includes a transducer for detecting a stimulus from an anatomic structure in an eye, the stimulus being indicative of a range to the object-of-regard.
20. The apparatus of claim 18, wherein the second actuator includes a micromechanical motor.