1. A system for wireless communication, comprising:a transmitter configured to transmit wireless messages;
a receiver configured to receive wireless messages;
a processor operably connected to the transmitter and the receiver; and
non-transient computer-readable media operably connected to the processor, containing instructions for causing the processor to perform a method comprising:
transmitting a wireless message while no interfering signals are detected;
then, if a confirmatory reply is not received within a predetermined interval, waiting a time period equal to the sum of a predetermined initial waiting interval plus a randomly selected delay within a predetermined initial contention window and then re-transmitting the wireless message;
then, if a confirmatory reply to the re-transmitted message is not received within a predetermined interval, waiting a predetermined second waiting interval plus a randomly selected delay within a predetermined second contention window, wherein the second waiting interval is shorter than the initial waiting interval, or the second contention window is shorter than the initial contention window; and
then, transmitting the wireless message.