Adaptive transmission rate and fragmentation threshold mechanism for local area networks
View Patent ↗An apparatus for adjusting the transmission bit rate and fragmentation threshold of a wireless station in response to transmission errors is disclosed. In particular, the illustrative embodiment of the present invention is based on a wireless station that employs both an IEEE 802.11 radio and a Bluetooth radio, and determines whether transmission errors of the IEEE 802.11 radio are due to fading, or interference from the Bluetooth radio. It will be clear to those skilled in the art how to make and use alternative embodiments of the present invention for protocols other than IEEE 802.11 and Bluetooth, as well as stations that employ wireline or non-RF-wireless transceivers.
1. An apparatus comprising:
a processor; and
a memory having instructions stored thereon that, in response to being executed by the processor, the instructions cause the apparatus to set a current bit rate and a current fragmentation threshold for transmitting a current set of one or more frames based at least in part on:
a measured signal quality of a set of one or more previously received acknowledgement frames corresponding to a set of one or more previously transmitted frames; and
error correction activity corresponding to the set of one or more previously transmitted frames, wherein the set of one or more previously transmitted frames has a previous bit rate and a previous fragmentation threshold,
wherein the current bit rate is set to a bit ru/cthn 1 is equal to the previous bit rate if:
the measured signal quality of the set of one or more previously received acknowledgement frames is less than a low signal quality threshold, and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated; or
the measured signal quality of acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the set of one or more previously transmitted frames, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a low error rate threshold.
2. The apparatus of claim 1 , wherein the memory has further instructions stored thereon that, in response to being executed by the processor, cause the apparatus to determine whether errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
3. The apparatus of claim 1 , wherein the current bit rate is set to a bit rate that is lower than the previous bit rate if:
the previous bit rate is greater than a minimum bit rate;
the measured signal quality of the set of one or more previously received acknowledgment frames is less than a low signal quality threshold; and
errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
4. The apparatus of claim 1 , wherein the current bit rate is set to a bit rate that is greater than the previous bit rate if:
the previous bit rate is less than a maximum bit rate;
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the set of one or more previously transmitted frames; and
an error rate based on the error correction activity of the set of one or more previously transmitted frames is less than a low error rate threshold.
5. The apparatus of claim 1 , wherein the current fragmentation threshold is set to a fragmentation threshold that is lower than the previous fragmentation threshold if:
the previous fragmentation threshold is greater than a minimum fragmentation threshold;
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold;
an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a high error rate threshold; and
errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated.
6. The apparatus of claim 1 , wherein the current fragmentation threshold is set to a fragmentation threshold that is greater than the previous fragmentation threshold if:
the previous fragmentation threshold is less than a maximum fragmentation threshold level;
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames remained constant during the transmission of the set of one or more previously transmitted frames; and
an error rate based on the error correction activity of the set of one or more previously transmitted frames decreased during the transmission of the set of one or more previously transmitted frames.
7. The apparatus of claim 1 , wherein the current fragmentation threshold is set to a fragmentation threshold that is equal to the previous fragmentation threshold if:
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold, an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a high error rate threshold, and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated; or
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is less than a high error rate threshold; or
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames remained constant during the transmission of the set of one or more previously transmitted frames. and an error rate based on the error correction activity of the set of one or more previously transmitted frames increased during the transmission of the set of one or more previously transmitted frames.
8. The apparatus of claim 1 , wherein the measured signal quality of the set of one or more previously received acknowledgement frames corresponding to the set of one or more previously transmitted frames is one of a signal strength or a signal-to-noise ratio.
9. The apparatus of claim 1 , wherein the error correction activity corresponding to the set of one or more previously transmitted frames is a retransmission of an unacknowledged frame.
10. A method comprising:
setting a current bit rate and a current fragmentation threshold for transmitting a current set of one or more frames based at least in part on a measured signal quality of a set of one or more previously received acknowledgement frames corresponding to a set of one or more previously transmitted frames, and error correction activity corresponding to the set of one or more previously transmitted frames, wherein the set of one or more previously transmitted frames has a previous bit rate and a previous fragmentation threshold; and
initiating the transmission of the current set of one or more frames at the current bit rate and the current fragmentation threshold,
wherein setting the current bit rate and the current fragmentation threshold comprises setting the current bit rate to a bit rate that is equal to the previous bit rate if:
the measured signal quality of the set of one or more previously received acknowledgement frames is less than a low signal quality threshold, and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated; or
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the corresponding set of one or more previously transmitted frames, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a low error rate threshold.
11. The method of claim 10 , wherein setting the current bit rate and the current fragmentation threshold comprises:
determining whether errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
12. The method of claim 10 , wherein setting the current bit rate and the current fragmentation threshold comprises setting the current bit rate to a bit rate that is lower than the previous bit rate if:
the previous bit rate is greater than a minimum bit rate;
the measured signal quality of the set of one or more previously received acknowledgment frames is less than a low signal quality threshold; and
errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
13. The method of claim 10 , wherein setting the current bit rate and the current fragmentation threshold comprises setting the current bit rate to a bit rate that is greater than the previous bit rate if:
the previous bit rate is less than a maximum bit rate;
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the corresponding set of one or more previously transmitted frames; and
an error rate based on the error correction activity of the set of one or more previously transmitted frames is less than a low error rate threshold.
14. The method of claim 10 , wherein setting the current bit rate and the current fragmentation threshold comprises setting the current fragmentation threshold to a fragmentation threshold that is lower than the previous fragmentation threshold if:
the previous fragmentation threshold is greater than a minimum fragmentation threshold;
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold;
an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a high error rate threshold; and
errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated.
15. The method of claim 10 , wherein setting the current bit rate and the current fragmentation threshold comprises setting the current fragmentation threshold to a fragmentation threshold that is greater than the previous fragmentation threshold if:
the previous fragmentation threshold is less than a maximum fragmentation threshold;
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames remained constant during the transmission of the set of one or more previously transmitted frames; and
an error rate based on the error correction activity of the set of one or more previously transmitted frames decreased during the transmission of the set of one or more previously transmitted frames.
16. The method of claim 10 , wherein setting the current bit rate and the current fragmentation threshold comprises setting the current fragmentation threshold to a fragmentation threshold that is equal to the previous fragmentation threshold if:
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold, an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a high error rate threshold, and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated; or
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is less than a high error rate threshold; or
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames remained constant during the transmission of the set of one or more previously transmitted frames, and an error rate based on the error correction activity of the set of one or more previously transmitted frames increased during the transmission of the set of one or more previously transmitted frames.
17. The method of claim 10 , wherein the measured signal quality of the set of one or more previously received acknowledgement frames corresponding to the set of one or more previously transmitted frames is one of a signal strength or a signal-to-noise ratio.
18. The method of claim 10 , wherein the error correction activity corresponding to the set of one or more previously transmitted frames is a retransmission of an unacknowledged frame.
19. A tangible computer-readable medium having instructions stored thereon, the instructions comprising:
instructions for setting a current bit rate and a current fragmentation threshold for transmitting a current set of one or more frames based at least in part on a measured signal quality of a set of one or more previously received acknowledgement frames corresponding to a set of one or more previously transmitted frames, and error correction activity corresponding to the set of one or more previously transmitted frames, wherein the set of one or more previously transmitted frames has a previous bit rate and a previous fragmentation threshold; and
instructions for initiating the transmission of the current set of one or more frames at the current bit rate and the current fragmentation threshold,
wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise instructions for setting the current bit rate to a bit rate that is equal to the previous bit rate if:
the measured signal quality of the set of one or more previously received acknowledgement frames is less than a low signal quality threshold, and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated; or
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the corresponding set of one or more previously transmitted frames, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is eater than a low error rate threshold.
20. The tangible computer-readable medium of claim 19 , wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise:
instructions for determining whether errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
21. The tangible computer-readable medium of claim 19 , wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise instructions for setting the current bit rate to a bit rate that is lower than the previous bit rate if:
the previous bit rate is greater than a minimum bit rate;
the measured signal quality of the set of one or more previously received acknowledgment frames is less than a low signal quality threshold; and
errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
22. The tangible computer-readable medium of claim 19 , wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise instructions for setting the current bit rate to a bit rate that is greater than the previous bit rate if:
the previous bit rate is less than a maximum bit rate;
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the corresponding set of one or more previously transmitted frames; and
an error rate based on the error correction activity of the set of one or more previously transmitted frames is less than a low error rate threshold.
23. The tangible computer-readable medium of claim 19 , wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise instructions for setting the current fragmentation threshold to a fragmentation threshold that is lower than the previous fragmentation threshold if:
the previous fragmentation threshold is greater than a minimum fragmentation threshold;
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold;
an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a high error rate threshold; and
errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated.
24. The tangible computer-readable medium of claim 19 , wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise instructions for setting the current fragmentation threshold to a fragmentation threshold that is greater than the previous fragmentation threshold if:
the previous fragmentation threshold is less than a maximum fragmentation threshold;
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames remained constant during the transmission of the corresponding set of one or more previously transmitted frames; and
an error rate based on the error correction activity of the set of one or more previously transmitted frames decreased during the transmission of the set of one or more previously transmitted frames.
25. The tangible computer-readable medium of claim 19 , wherein the instructions for setting the current bit rate and the current fragmentation threshold comprise instructions for setting the current fragmentation threshold to a fragmentation threshold that is equal to the previous fragmentation threshold if:
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold, an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a high error rate threshold, and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated; or
the measured signal quality of the set of one or more previously received acknowledgment frames is greater than a high signal quality threshold, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is less than a high error rate threshold; or
the measured signal quality of the acknowledgement frames in the set of one or more previously received acknowledgement frames remained constant during the transmission of the set of one or more previously transmitted frames, and an error rate based on the error correction activity of the set of one or more previously transmitted frames increased during the transmission of the set of one or more previously transmitted frames.
26. The tangible computer-readable medium of claim 19 , wherein the measured signal quality of the set of one or more previously received acknowledgement frames corresponding to the set of one or more previously transmitted frames is one of a signal strength or a signal-to-noise ratio.
27. The tangible computer-readable medium of claim 19 . wherein the error correction activity corresponding to the set of one or more previously transmitted frames is a retransmission of an unacknowledged frame.
28. An apparatus comprising:
means for setting a current bit rate and a current fragmentation threshold for transmitting a current set of one or more frames based at least in part on:
a measured signal quality of a set of one or more previously received acknowledgement frames corresponding to a set of one or more previously transmitted frames; and
error correction activity corresponding to the set of one or more previously transmitted frames, wherein the set of one or more previously transmitted frames has a previous bit rate and a previous fragmentation threshold,.
wherein the current bit rate is set to a bit rate that is equal to the previous bit rate if:
the measured signal quality of the set of one or more previously received acknowledgement frames is less than a low signal quality threshold. and errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally uncorrelated; or
the measured signal quality of acknowledgement frames in the set of one or more previously received acknowledgement frames increased during the transmission of the set of one or more previously transmitted frames, and an error rate based on the error correction activity of the set of one or more previously transmitted frames is greater than a low error rate threshold.
29. The apparatus of claim 28 , further comprising:
means for determining whether errors corresponding to the error correction activity of the set of one or more previously transmitted frames are temporally correlated.
30. The apparatus of claim 28 , wherein the measured signal quality of the set of one or more previously received acknowledgement frames corresponding to the set of one or more previously transmitted frames is one of a signal strength or a signal-to-noise ratio.
31. The apparatus of claim 28 , wherein the error correction activity corresponding to the set of one or more previously transmitted frames is a retransmission of an unacknowledged frame.