ST-MAC: Spatial-Temporal MAC Scheduling for Underwater Sensor Networks

Asymmetric Propagation Delay-Aware TDMA MAC Protocol for Mobile Underwater Acoustic Sensor Networks

“…In high traffic scenarios, packet collisions of MUASNs not only severely degrade network throughput, but also cause intolerably long latency due to uncertain number of retransmissions. On the other hand, contention-free MAC protocols [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] are significantly superior to contention-based ones in high traffic scenarios because the medium is orthogonalized in a certain domain.…”

“…However, this large propagation delay is being re-interpreted rather positively, and TDMA approaches in MUASN are considered to be one of the most efficient MAC protocols. In particular, spatial reuse MACs [28][29][30][31][32][33][34][35][36][37] take advantage of a large propagation delay for concurrent transmissions without collisions at receivers by considering possible interferences from neighbor nodes.…”

Echoes from the deep : communication scheduling, localization and time-synchronization in underwater acoustic sensor networks

“…Although TDMA is possible in underwater communication, this scheduling approach is generally considered inefficient because of the large propagation-delays of the acoustic signals and resulting large guard-times required. Scheduling approaches such as ST-MAC [15] and STUMP [16] schedule in such a way that the inefficiency of the large propagation delays is avoided. These scheduled based approaches use estimation of the propagation delay to schedule the reception of the packet.…”

“…At the same time there is an increasing interest in scheduling approaches for underwater communication. Examples of scheduling approaches for underwater communication include ST-MAC [15], STUMP [16].…”

“…A valid schedule should follow certain constraints to avoid packet collisions at the receiver. In both [15] and [19], the scheduling constraints for underwater communication have been identified. They are derived from the four possible conflicts that may occur during communication, namely: TX-TX conflict, TX-RX conflict, RX-RX conflict and RX interference (see Figure 2.3).…”