ZigBee, thread and BLE co-existence with 2.4 GHz WIFI
A system and method of minimizing interference and retries in an environment where two or more network protocols utilize the same frequency spectrum is disclosed. A lower-power network controller is co-located with a WIFI controller. The lower-power network controller parses incoming packets as they are received and generates a request signal once it is determined that the incoming packet is destined for this device. This maximizes the likelihood that no WIFI traffic will occur while the incoming packet is being received.
1. A system comprising:
a WIFI controller, comprising a request signal used as an input to request exclusive access to a shared medium and a grant signal used as an output indicating that the exclusive access to the shared medium has been granted; and
a lower-power network controller, comprising a processing unit and an associated memory element, wherein the lower-power network controller is configured to:
determine when there is a lower-power network packet to transmit;
calculate a random delay to be used by the lower-power network controller prior to attempting to transmit the lower-power network packet on the shared medium; and
assert the request signal a predetermined amount of time after determining that there is a lower-power network packet to transmit, wherein the predetermined amount of time is determined based on the random delay.
2. The system of claim 1 , wherein the predetermined amount of time is less than the random delay by a predetermined value.
3. The system of claim 1 , wherein the lower-power network controller is further configured to transmit the lower-power network packet after the random delay only if the grant signal is active.
4. The system of claim 1 , wherein the WIFI controller further comprises a status signal used as an output to indicate whether the WIFI controller is active.
5. The system of claim 4 , wherein the lower-power network controller is further configured to determine if the WIFI controller is active prior to transmitting the lower-power network packet.
6. The system of claim 4 , wherein the lower-power network controller is further configured to not transmit the lower-power network packet if the grant signal is not active or the WIFI controller is active.
7. A method of simultaneously operating a WIFI network and a lower-power network, comprising:
determining using a lower-power network controller, when there is a lower-power network packet to transmit;
calculating a random delay to be used by the lower-power network controller prior to attempting to transmit the lower-power network packet on a shared medium; and
asserting a request signal from the lower-power network controller to a WIFI controller a predetermined amount of time after determining that there is a lower-power network packet to transmit, wherein the predetermined amount of time is determined based on the random delay, and wherein the request signal is used as an input to the WIFI controller to request exclusive access to the shared medium.
8. The method of claim 7 , wherein the predetermined amount of time is less than the random delay by a predetermined value.
9. The method of claim 7 , wherein the WIFI controller outputs a grant signal if exclusive access to the shared medium has been granted.
10. The method of claim 9 , further comprising:
transmitting, using the lower-power network controller, the lower-power network packet after the random delay only if the grant signal is active.
11. The method of claim 9 , wherein the WIFI controller outputs a status signal to indicate whether the WIFI controller is active.
12. The method of claim 11 , further comprising:
determining, using the lower-power network controller, if the WIFI controller is active prior to transmitting the lower-power network packet.
13. The method of claim 11 , wherein the lower-power controller does not transmit the lower-power network packet if the grant signal is not active or the WIFI controller is active.