Reliable Communications Across Parallel Asynchronous Channels With Arbitrary Skews

Transmissions across asynchronous communication channels are subject to delay injection attacks, which can cause an arbitrary number of skews. That is, such attacks can cause an arbitrary number of transmitted signals to arrive after the first signal of the next transmission has arrived. The (common) assumption that despite the delays, all signals from the ith transmission arrive at the decoder before any signal from the (i+2)nd transmission arrives is called a no switch assumption. This paper presents a self-synchronizing, zero-latency, zero-error coding scheme that requires no acknowledge and can decode transmissions distorted by an arbitrary number of skews that obey this no switch assumption. The rate associated with the coding scheme provides a lower bound of 0.6942 for the (zero-error) capacity of such a channel. It is further shown that zero-error channel capacity of the channel is upper bounded by 0.7248. Finally, this paper presents bounds on the (zero-error) capacity of a channel for which the number of transmissions that can mix with one another is large.