Collision detection method
A wireless device may receive packets according to a protocol, such as Bluetooth, and may rapidly react to receive an interfering RF packet instead of dropping the first RF packet and the interfering RF packet, to decrease message delay due to collisions in high device density environments. When a received signal strength indicator (RSSI) difference between the interfering RF packet and the first RF packet exceeds a threshold, the device may detect the interfering packet and resync a portion of its circuitry to lock on to and receive the interfering packet. The wireless receiver may detect the interfering RF packet by detecting one or more of: a specific resync byte sequence, an increase in RSSI, or a phase shift. Additionally, a wireless device may add the specific resync byte sequence to an RF packet of a standard protocol.
1. A wireless device comprising:
an antenna configured to communicate wireless signals;
a transceiver operably connected to the antenna, wherein the transceiver is configured to:
detect a first RF packet via the antenna;
synchronize to and demodulate the first RF packet to create demodulated bits;
store the demodulated bits of the first RF packet in a buffer;
during the demodulation of the first RF packet, detect a second RF packet, wherein the second RF packet further comprises a preamble, a resync byte sequence prior to the preamble, a payload subsequent to the preamble, and one or more bits of dead time between the resync byte sequence and the preamble, wherein to detect the second RF packet comprises to detect the resync byte sequence;
upon detection of the second RF packet, synchronize to the second RF packet and clear the demodulated bits from the buffer during the dead time;
demodulate the second RF packet; and
store the demodulated bits from the second RF packet in the buffer.
2. The wireless device of claim 1 , wherein the first and second RF packets comprise Bluetooth packets.
3. The wireless device of claim 1 , wherein to detect the second RF packet further comprises to detect an increase in RSSI greater than or equal to a threshold during receipt of the first RF packet.
4. The wireless device of claim 3 , wherein the threshold is 10 dB.
5. The wireless device of claim 1 , wherein to detect the second RF packet further comprises to detect an increase in RSSI greater than or equal to a threshold during demodulation of the first RF packet.
6. The wireless device of claim 1 , wherein to detect the second RF packet further comprises to detect a phase shift in one or more data symbols during receipt of the first RF packet.
7. The wireless device of claim 1 , wherein the second RF packet comprises a lighting control command.
8. A method of receiving an interfering RF packet, the method comprising:
detecting a first RF packet;
synchronizing to and demodulating the first RF packet to create demodulated bits;
storing the demodulated bits of the first RF packet in a buffer;
while demodulating the first RF packet, detecting a second RF packet, wherein the second RF packet comprises a preamble, a resync byte sequence prior to the preamble, and a payload subsequent to the preamble, and one or more bits of dead time between the resync byte sequence and the preamble, wherein detecting the second RF packet comprises detecting the resync byte sequence;
upon detecting the second RF packet, synchronizing to the second RF packet and clearing the demodulated bits of the first RF packet from the buffer during the dead time;
demodulating the second RF packet; and
storing the demodulated bits from the second RF packet in the buffer.
9. The method of claim 8 , wherein the first and second RF packets are Bluetooth packets.
10. The method of claim 8 , wherein detecting the second RF packet further comprises detecting an increase in RSSI while receiving the first RF packet.
11. The method of claim 10 , wherein the increase in RSSI is greater than a threshold.
12. The method of claim 11 , wherein the threshold is 10 dB.
13. The method of claim 8 , wherein detecting the second RF packet further comprises detecting a phase shift in one or more data symbols while receiving the first RF packet.
14. The method of claim 8 , wherein the second RF packet comprises a lighting control command.