Method for IoT device to stagger TX and save power
Disclosed are methods and systems for delaying packet transmissions over a wireless communication channel until a more favorable channel condition is detected. A device may measure a channel metric when it receives periodic beacon signals. The device may compare the channel metric against a programmed metric threshold. If the channel metric is less than the metric threshold, the device may delay the transmission of a packet until a later transmission window or transmit opportunity (TXOP) when the channel metric rises above the metric threshold, indicating the presence of a more favorable condition for transmission, or until a preconfigured timeout period elapses before the more favorable condition is found.
1. A method of operating a wireless local area network (WLAN) device, comprising:
receiving, by the WLAN device, a plurality of beacon signals transmitted by an access point (AP) over a WLAN channel;
monitoring, by the WLAN device, a channel metric indicative of a signal quality of the WLAN channel based on the plurality of beacon signals;
determining, by the WLAN device, a timeout period associated with a packet to transmit;
waiting, by the WLAN device, to transmit the packet until the channel metric exceeds a predetermined threshold within the timeout period or otherwise when the timeout period elapses; and
after the channel metric exceeds the predetermined threshold within the time period or the time period elapses, transmitting, by the WLAN device, the packet over the WLAN channel, wherein transmission of the packet comprises a first transmission of the packet.
2. The method of claim 1 , wherein the channel metric comprises a received signal strength indicator (RSSI) of the WLAN channel.
3. The method of claim 1 , wherein the channel metric comprises a signal to noise ratio (SNR) of the WLAN channel.
4. The method of claim 1 , wherein the channel metric comprises one or more of an adjacent channel interference (ACI) of the WLAN channel, a noise level of the WLAN channel, a channel condition number indicative of a quality of a channel matrix of a multiple-in-multiple-out (MIMO) channel of the WLAN channel, or eigen values of the channel matrix.
5. The method of claim 1 , wherein determining, by the WLAN device, the timeout period associated with the packet to transmit comprises:
initializing a timeout counter with a maximum time to delay transmitting the packet;
counting down the timeout counter while the packet is waiting to be transmitted; and
declaring the timeout period elapses when the timeout counter reaches zero.
6. The method of claim 1 , further comprising:
measuring, by the WLAN device, a signal power of the WLAN channel; and
detecting, by the WLAN device, a transmission window in which the signal power of the WLAN channel is below a detection threshold,
and wherein transmitting, by the WLAN device, the packet over the WLAN channel comprises transmitting the packet during the transmission window.
7. The method of claim 1 , wherein transmitting, by the WLAN device, the packet over the WLAN channel comprises transmitting the packet at a highest data rate supported by the channel metric for a predetermined packet error rate.
8. The method of claim 1 , wherein the predetermined threshold indicates a desired signal quality of the WLAN channel for transmitting the packet.
9. The method of claim 1 , wherein the predetermined threshold is dynamically adjusted based on a plurality of channel metrics monitored based on the plurality of beacon signals.
10. The method of claim 1 , further comprising:
receiving, by the WLAN device, a packet over the WLAN channel; and
measuring, by the WLAN device, the channel metric of the WLAN channel based on the packet.
11. A wireless local area network (WLAN) device, comprising:
a processing device configured to:
receive a plurality of beacon signals transmitted by an access point (AP) over a WLAN channel;
monitor a channel metric indicative of a signal quality of the WLAN channel based on the plurality of beacon signals;
determine a timeout period associated with a packet to transmit;
wait to transmit the packet until the channel metric exceeds a predetermined threshold within the timeout period or otherwise when the timeout period elapses; and
after the channel metric exceeds the predetermined threshold within the time period or the time period elapses, transmit the packet over the WLAN channel, wherein transmission of the packet comprises a first transmission of the packet.
12. The device of claim 11 , wherein the channel metric comprises a received signal strength indicator (RSSI) of the WLAN channel.
13. The device of claim 11 , wherein the channel metric comprises one or more of an adjacent channel interference (ACI) of the WLAN channel, a signal to noise ratio (SNR) of the WLAN channel, a noise level of the WLAN channel, a channel condition number indicative of a quality of a channel matrix of a multiple-in-multiple-out (MIMO) channel of the WLAN channel, or eigen values of the channel matrix.
14. The device of claim 11 , wherein the processing device configured to determine the timeout period associated with the packet to transmit comprises the processing device being further configured to:
initialize a timeout counter with a maximum time to delay transmitting the packet;
count down the timeout counter while the packet is waiting to be transmitted; and
declare the timeout period elapses when the timeout counter reaches zero.
15. The device of claim 11 , wherein the processing device is further configured to:
measure a signal power of the WLAN channel; and
detect a transmission window in which the signal power of the WLAN channel is below a detection threshold,
and wherein the processing device configured to transmit the packet over the WLAN channel comprises the processing device being further configured to transmit the packet during the transmission window.
16. The device of claim 11 , wherein the processing device configured to transmit the packet over the WLAN channel comprises the processing device being further configured to transmit the packet at a highest data rate supported by the channel metric for a predetermined packet error rate.
17. The device of claim 11 , wherein the processing device is further configured to:
dynamically adjust the predetermined threshold based on a plurality of channel metrics monitored based on the plurality of beacon signals.
18. The device of claim 11 , wherein the processing device is further configured to:
receive a packet over the WLAN channel; and
measure the channel metric of the WLAN channel based on the packet.
19. An wireless local area network (WLAN) device, comprising:
one or more antennas configured to transmit or receive over a WLAN channel;
a processing device configured to:
receive a plurality of beacon signals from the one or more antennas, wherein the plurality of beacon signals is received by the one or more antennas from an access point (AP) over the WLAN channel;
monitor a channel metric indicative of a signal quality of the WLAN channel based on the plurality of beacon signals;
determine a timeout period associated with a packet to transmit;
wait to transmit the packet until the channel metric exceeds a predetermined threshold within the timeout period or otherwise when the timeout period elapses; and
after the channel metric exceeds the predetermined threshold within the time period or the time period elapses, transmit the packet from the one or more antennas over the WLAN channel, wherein transmission of the packet comprises a first transmission of the packet.
20. The WLAN device of claim 19 , wherein the channel metric comprises a received signal strength indicator (RSSI) of the WLAN channel.