Delay-Bounded Medium Access for Unidirectional Wireless Links

Consider a wireless network where links may be unidirectional, that is, a computer node A can broadcast a message and computer node B will receive this message but if B broadcasts then A will not receive it. Assume that messages have deadlines. We propose a medium access control (MAC) protocol which replicates a message in time with carefully selected pauses between replicas, and in this way it guarantees that for every message at least one replica of that message is transmitted without collision. The protocol ensures this with no knowledge of the network topology and it requires neither synchronized clocks nor carrier sensing capabilities. We believe this result is significant because it is the only MAC protocol that offers an upper bound on the message queuing delay for unidirectional links without relying on synchronized clocks. Delay-Bounded Medium Access for Unidirectional Wireless Links1 1 Due to space limitations, some results in this conference version are omitted. See the extended version for details [11]. Bjorn Andersson, Nuno Pereira, Eduardo Tovar IPP Hurray Research Group Polytechnic Institute of Porto, Portugal {bandersson, npereira, emt}@dei.isep.ipp.pt