Coordination-free deterministic communication for embedded system using the BBC encoding

A major problem in the field of communication is the management of the shared transmission medium. For example, if multiple radios are transmitting simultaneously on the same frequency the signals may overlap, leading to interference. Some wireless techniques require the sender to sense before transmitting, introducing non-determinism as they wait a random delay before trying again. In real-time systems, unpredictable delays are undesirable and numerous techniques have been developed to organize the behavior of transmitters to eliminate this problem. Existing techniques to eliminate “sense-before-send” rely on cooperation and coordination among all senders. The technique demonstrated in this paper uses the BBC encoding scheme to achieve deterministic wireless communications. With this technique, senders can transmit without regard for the state of the medium or coordination with other senders, and receivers can tease apart messages sent simultaneously with a high probability of success. We evaluate implementations of the technique in a wired environment using a simple unmanaged, single-wire bus, and also a wireless implementation with a simple AM radio.