Channel control based on error correction values
A computing device configured for wireless communication may effectively control adaptation to channel conditions. The device may be configured to identify and classify conditions impacting performance of a channel so that appropriate adaptations may be made. Interference may be detected by correlating received signal strength and packet errors. High received signal strength correlated to a high packet error rate may signify presence of a source of interference. Once a source of interference is detected, other criteria may be used to determine the nature of the interference so that an adaptation that is minimally disruptive of applications can be selected. Additionally, channel degradation may be predicted by monitoring trends in error rates, including Forward Error Correction rates, and adaptation may be used before packet error rates exceed an unacceptable level.
1. A method of operating a computing device comprising a wireless network interface, the method comprising:
for each packet of a plurality of packets communicated over a channel, when performing error correction, computing an error metric by counting error corrections performed by the error correction to correct errors introduced by transmission;
obtaining a signal strength indication indicating a signal strength of the channel;
analyzing the error metric to determine whether the error metric exceeds an error metric threshold; and
providing first logic that will be conditionally executed if determined that the error metric threshold is exceeded by the error metric, the first logic comprising:
determining whether the signal strength indication and the error metric are both sufficiently high to cause a change in channel, and responsive to determining that the signal strength indication and the error metric are both sufficiently high, causing a change in channel from the channel to a new channel;
providing second logic that will be conditionally executed if determined that the error metric threshold is not exceeded by the error metric, the second logic comprising:
determining whether the signal strength indication is sufficiently high and whether the error metric is sufficiently low to initiate an adaptation process for communications over the channel, wherein the adaptation process comprises increasing a data rate for transmission of packets in the channel.
2. The method of claim 1 , wherein the causing a change in channel further comprises:
identifying a period of low activity for communications in the channel; and
responsive to identifying the period of low activity, switching channels according to the identified period of low activity.
3. A method according to claim 1 , wherein the method is performed by a driver for the wireless network interface.
4. An apparatus for interfacing to a wireless network, the apparatus comprising:
a receive circuit that, when the apparatus is operating, receives packets over a channel, the packets received from a transmit circuit that transmits communications over the channel, the receive circuit providing a signal strength indication;
an error correction circuit coupled to the receiver, the error correction circuit, when the apparatus is operating, performing error correction on the packets and counting errors introduced to the packets by transmission thereof over the channel;
processing hardware and storage hardware, the storage hardware storing instructions that when executed by the processing hardware perform a process comprising:
providing an error metric based on the counting of errors;
determining whether the error metric exceeds an error threshold;
providing first logic that is executed if and when it is determined that the error threshold is exceeded, the first logic comprising:
determining if the signal strength indication and the error metric are sufficiently high, and responding to determining that the signal strength indication and the error metric are sufficiently high by changing from the channel to a new channel;
providing second logic that is executed if and when it is determined that the error threshold is not exceeded, the second logic comprising:
determining if the signal strength indication is sufficiently high and the error rate is sufficiently low to increase a data rate for the communications over the channel, and when so determined, increasing the data rate for the communications over the channel.
5. The apparatus of claim 4 , wherein the increasing the data comprises altering an error correction code coding rate.
6. The apparatus of claim 4 , further comprising:
a controller coupled with the error correction circuit and the transmit circuit, the controller, when operating, detecting a trend in a degree of error correction according to the counting, and according to the trend, regulating transmit power of the transmit circuit based on the detected trend.
7. A method according to claim 1 , wherein the error metric threshold is set to a predetermined level.
8. A method according to claim 1 , wherein the error metric threshold is determined adaptively.
9. A method according to claim 1 , wherein the determining whether the signal strength indication is sufficiently high comprises comparing the signal strength indication to a second threshold, and where the determining whether the error metric is sufficiently high comprises comparing the error metric to a third threshold.
10. A method according to claim 9 , wherein the third threshold is different than the error metric threshold.
11. An apparatus according to claim 4 , wherein the determining if the signal strength indication and the error metric are sufficiently high is further responded to by obtaining a measure of utilization of the channel, and determining, based on the measure of utilization, whether to change the channel or to transmit a Request to Send/Request to Clear (RTS/CTS).
12. An apparatus according to claim 11 , wherein the measure of utilization is based on a plurality of signal strength indications.
13. A method of controlling wireless communication performed by a computing device comprising a wireless network interface, processing hardware, and storage hardware, the method performed by the processing hardware and comprising:
communicating with a remote device via a channel between the wireless network interface and the remote device, the communicating comprising receiving data transmitted at a data rate by the remote device, the communicating comprising performing error correction on data received via the channel, the data having been encoded at a data rate by the remote device with an encoding scheme;
obtaining an indication of an error rate of the error correcting and obtaining an indication of signal strength of the channel;
comparing the error rate with an error rate threshold to determine whether the threshold is exceeded by the error rate;
when determined that error rate does not exceed the threshold, determining whether the signal strength is sufficiently high and whether the error rate is sufficiently low to trigger an increase in the data rate, and when so determined adjusting the encoding scheme for the channel to increase the data rate; and
when determined that the error rate does exceed the threshold, determining whether the signal strength is sufficiently high and whether the error rate is sufficiently high to trigger a channel change, and when so determined causing a channel change from the channel to a new channel.
14. A method according to claim 13 , wherein not determined that the signal strength is sufficiently high and the rate is sufficiently high, performing an adaption on the channel, the adaption comprising a power transmission level adjustment or a data rate adjustment.