A survey of practical issues in underwater networks
WUWNet '06 Proceedings of the 1st ACM international workshop on Underwater networks
Proceedings of the 12th annual international conference on Mobile computing and networking
Understanding spatio-temporal uncertainty in medium access with ALOHA protocols
Proceedings of the second workshop on Underwater networks
Distributed CDMA-based MAC Protocol for Underwater Sensor Networks
LCN '07 Proceedings of the 32nd IEEE Conference on Local Computer Networks
MU-Sync: a time synchronization protocol for underwater mobile networks
Proceedings of the third ACM international workshop on Underwater Networks
A reservation mac protocol for ad-hoc underwater acoustic sensor networks
Proceedings of the third ACM international workshop on Underwater Networks
Performance of a Propagation Delay Tolerant ALOHA Protocol for Underwater Wireless Networks
DCOSS '08 Proceedings of the 4th IEEE international conference on Distributed Computing in Sensor Systems
A CDMA-based medium access control for underwater acoustic sensor networks
IEEE Transactions on Wireless Communications
A linear time synchronization algorithm for underwater wireless sensor networks
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Time Synchronization Protocol with Minimum Message Communication for High Latency Networks
Wireless Personal Communications: An International Journal
System Design Considerations for Undersea Networks: Link and Multiple Access Protocols
IEEE Journal on Selected Areas in Communications
Comparison and Evaluation of the T-Lohi MAC for Underwater Acoustic Sensor Networks
IEEE Journal on Selected Areas in Communications
RIPT: A Receiver-Initiated Reservation-Based Protocol for Underwater Acoustic Networks
IEEE Journal on Selected Areas in Communications
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In a wireless network, where propagation delay is high but known, slotted Aloha (S-Aloha) is synchronized with respect to the receiver's time slots. Since the transmitter knows the propagation delay to its receiver, after a frame is generated, the transmitter introduces a suitable delay before its transmission, such that the frame arrives exactly in a slot at the receiver. However, in an underwater wireless network, due to significantly less signal propagation speed, the channel dynamics has a significant effect on the time dispersion of propagation speed. Due to this uncertainty in propagation speed, even if the transmitter-receiver distance is exactly known, it is likely that a perfect synchronization at the receiver is not possible. In this paper, we first show that, even a little-less-than-perfect synchronization at the receiver reduces the throughput of receiver synchronized S-Aloha (RSS-Aloha) to that of pure Aloha. We modify the RSS-Aloha for underwater by accommodating the error in delay estimate while deciding the receiver-end slot size. Via probabilistic analysis, supported by simulations, we show that our proposed modified protocol offers a gradual increase in throughput as the propagation delay uncertainty decreases. We also show that the throughput of our proposed modified protocol is consistently higher compared to the transmitter synchronized S-Aloha when operating under the same propagation delay uncertainty. However, when the uncertainty is high, delay performance of the modified RSS-Aloha remains poorer than that of the transmitter synchronized S-Aloha in a system with smaller nodal communication range.