Convex Optimization
A survey of practical issues in underwater networks
WUWNet '06 Proceedings of the 1st ACM international 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
R-MAC: An Energy-Efficient MAC Protocol for Underwater Sensor Networks
WASA '07 Proceedings of the International Conference on Wireless Algorithms,Systems and Applications
On the relationship between capacity and distance in an underwater acoustic communication channel
ACM SIGMOBILE Mobile Computing and Communications Review
Prospects and problems of wireless communication for underwater sensor networks
Wireless Communications & Mobile Computing - Underwater Sensor Networks: Architectures and Protocols
IEEE Transactions on Wireless Communications
INFOCOM'10 Proceedings of the 29th conference on Information communications
Cross-Layer combining of adaptive Modulation and coding with truncated ARQ over wireless links
IEEE Transactions on Wireless Communications
Multichannel random access in OFDMA wireless networks
IEEE Journal on Selected Areas in Communications
Nonbinary LDPC Coding for Multicarrier Underwater Acoustic Communication
IEEE Journal on Selected Areas in Communications
The challenges of building mobile underwater wireless networks for aquatic applications
IEEE Network: The Magazine of Global Internetworking
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In this paper, we investigate OFDM based MAC protocols for underwater acoustic networks. Due to the severe multi-path effects of underwater acoustic channels, the guard time between OFDM blocks becomes significant, which greatly degrades the system rate. In addition, the highly dynamic nature of underwater acoustic channels makes it hard to choose the optimal transmitting power and modulation mode. Furthermore, the bandwidth of most current OFDM modems is only around tens of kHz, which is much less than the available bandwidth in a network with short range communication links. All these challenges make existing OFDM based MAC protocols for designed terrestrial wireless networks unsuitable. In this work, we propose a new MAC protocol called TDM with FDM over OFDM MAC protocol (TFO-MAC), which smoothly couples TDM with FDM/OFDM for the uplink traffic in a cellular like underwater acoustic network. In TFO-MAC, the acoustic channel is divided into multiple sub-channels in frequency via FDM technology, and OFDM modulation is used in every sub-channel. In addition, time is partitioned into slots and every node can use different channels in different slots. Powerful base stations in the network are responsible for the dynamic channel assignment, power optimization and modulation method selection for all nodes in every slot. We formulate the problem as a mixed integer programming problem and propose an efficient greedy algorithm to solve it. Simulation results show that TFO-MAC can achieve high throughput with good fairness.