Comparing underwater MAC protocols in real sea experiments (original) (raw)
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Comparing underwater MAC protocols in real sea experiment
2013
Underwater acoustic networks (UANs) have drawn significant attention from both academia and industry in recent years. Even though many underwater MAC protocols have been proposed and studied based on simulations and theoretical analysis, few work has been conducted to test and evaluate these protocols in a multi-hop real sea experiment. Due to the harsh acoustic channel condition caused by complex multi-path environment, fast varying acoustic channel and heterogenous channel quality, current simulators can hardly tell us how the protocols work in the real world. Along this direction, we conduced real sea experiments at Atlantic Ocean with 9 nodes deployed forming a multi-hop string network. In this experiment, the performance of three representative MAC protocols, random access based UW-Aloha, handshaking based SASHA, and scheduling based pipelined transmission MAC (PTMAC) are compared and analyzed at both packet behavior and node behavior levels. The end-to-end performance of these three protocols are also tested and studied in terms of throughput, delay, and packet delivery ratio. From field experiment results, the high packet loss rate and significant channel asymmetry, temporal and spatial transmission range uncertainty and delayed data transmissions are discovered to have evidential effects on the MAC performance. We provide some inspirations to address these observed issues in MAC design for real multi-hop networks.
Performance evaluation of underwater MAC protocols: From simulation to at-sea testing
OCEANS 2011 IEEE - Spain, 2011
Many MAC protocols have been proposed for underwater sensor networks, usually variants of wellknown terrestrial approaches. Although performance comparisons among different MAC protocols have been estimated by simulations, e.g. [1], [2], no extensive comparison has yet been performed by means of at-sea experiments.
Comparative Analysis of MAC Protocols and Strategies for Underwater Applications
Wireless Personal Communications, 2016
This research focuses on the comparison of the throughput performance of MAC protocols designed for underwater acoustic networks. Our emphasis was to study the key features of the existing MAC protocols for underwater acoustic communications and provide analytical analysis where feasible. We compared some selected underwater MAC protocols like UAN-ALOHA, CSMA, MACA, MACA-EA and S-FAMA and analyzed their throughputs. We chose to evaluate possible improvements in the throughput of S-FAMA by using the retry mechanism. We found the retry mechanism only showed marginal improvement in the throughput. The proposed mechanisms may not have practical efficacy, however, this mechanism may be helpful in saving energy of the sensor nodes by preventing the repetition of the entire transmission cycle.
MAC Protocols in Underwater Wireless Sensor Networks: Issues and Simulations
Underwater Acoustic Wireless Sensor Network (UAWSN) use acoustic signals to transmit data. Acoustic signals in underwater environment have high bit error rate, long propagation delay and limited bandwidth. Another constraint in UWASN is energy. Due to these constraints, design of energy and bandwidth efficient and propagation delay aware MAC protocol is a great challenge in UWASN. Underwater sensor nodes have to share medium. The main role of the MAC layer protocol is to decide when a node accesses a shared medium and to resolve any conflicts between nodes. In this paper, we evaluate the performance of three famous underwater MAC protocols UWAN-MAC[1], R-MAC[2] and Slotted FAMA[3] in terms of packet drop rate, throughput and energy consumption. We have used Aquasim simulator to evaluate MAC protocols.
2008
Unlike the terrestrial wireless networks that utilize the radio channel, underwater networks use the acoustic channel, which poses research challenges in the medium access control (MAC) protocol design due to its low bandwidth and high propagation delay characteristics. Since most of the MAC protocols for wireless terrestrial networks have been designed with negligible propagation delay in mind, they generally perform poorly when applied directly in underwater acoustic networks, especially for the case of handshaking-based protocols. In this paper, we propose a MACA-based MAC protocol with packet train to multiple neighbors (MACA-MN). It improves the channel utilization by forming a train of packets destined for multiple neighbors during each round of handshake, which greatly reduces the relative proportion of time wasted due to the propagation delays of control packets. This approach also reduces the hidden terminal problem. Our simulations show that the MACA-MN is able to achieve much higher throughput than the MACA protocol.
Slotted FAMA: a MAC protocol for underwater acoustic networks
2006
Long propagation delays and low bit rates of underwater acoustic networks make these systems fundamentally different from the packet radio networks. As a consequence, many of the network protocols designed for radio channels are either not applicable, or have extremely low efficiency over underwater acoustic channels. These facts necessitate a dedicated design of protocols for an underwater acoustic network.
Comparative Performance Evaluation of MAC Layer Protocols for Underwater Wireless Sensor Networks
Modern Applied Science, 2012
Underwater Acoustic Wireless Sensor Networks (UAWSN) use acoustic communication for transmitting data. High bit error rate, long propagation delay and limited bandwidth in underwater harsh environment are big issues for designing wireless sensor networks for many applications including ocean monitoring. Another consideration in UWASN is energy constraint. Similar to other wireless sensor networks the design process of energy and efficient bandwidth and also propagation-delay-aware MAC protocols are great challenges in UWASN. In this paper, the performance of three underwater MAC protocols for underwater environment, R-MAC, Slotted FAMA and UWAN-MAC are evaluated. Throughput, energy consumption and packet drop rate are those parameters which are considered for evaluating their performances. These protocols are implemented in Aqua-Sim, an NS-2 based simulator for underwater sensor networks. The simulation results show the effectiveness of the proposed method.
State-of-the-Art in MAC Protocols for Underwater Acoustics Sensor Networks
Lecture Notes in Computer Science, 2007
Many potential applications such as ocean sampling network, environment monitoring, undersea exploration, disaster prevention, assisted navigation, and mine reconnaissance can be provided by deploying the Underwater Acoustic Sensor Networks. Because of the peculiarities of acoustic communication in underwater, the MAC protocol which play a role of managing and controlling the channels, must overcome the required of energy consumption, propagation delay and time synchronize as well as other factors. In this paper, we summarize and classify some current proposed MAC protocols as well as make a comparison table in order to bring out the current development of a very interesting research area. Beside, we briefly introduce our suggestion of MAC mechanisms for Underwater Acoustic Sensor Networks (UWASNs) named Gain-time and Guard-time TDMA mechanism and UWA-NAV mechanism.
DC-MAC: A data-centric multi-hop MAC protocol for underwater acoustic sensor networks
2011 IEEE Symposium on Computers and Communications (ISCC), 2011
Due to the unique characteristics of long signal propagation, high error rate and low bandwidth in the underwater environment, the design of the medium access control (MAC) protocol for underwater acoustic networks poses significant challenges. The previous MAC protocols designed for flexible communication models have limited achievements in performance. In this paper, we consider a practical application and propose a data-centric multi-hop MAC protocol, called DC-MAC, to enhance the performance on throughput and average end-to-end packet transmission delay. Our design uses multi-channel strategy to limit transmission interference by creating multiple collision domains, and dynamic collisionfree polling strategy to offer efficient protocol handshake. We analyze the saturation throughput performance and conduct extensive simulation experiments to study the throughput and delay performance. Comparing to slotted FAMA which is a potential MAC protocol candidate for the same environment, our results show that DC-MAC outperforms its peer.
Aloha-Based MAC Protocols with Collision Avoidance for Underwater Acoustic Networks
2007
Unlike terrestrial networks that mainly rely on radio waves for communications, underwater networks utilize acoustic waves, which have comparatively lower loss and longer range in underwater environments. However, the use of acoustic waves pose a new research challenge in the networking area. While existing network schemes for terrestrial sensor networks are mainly designed for negligible propagation delay and high data rate, underwater acoustic communications are characterized by high propagation delay and low data rate. These terrestrial schemes, when directly applied to the underwater channel, will under-utilize its already limited capacity. We investigate how the underwater channel's throughput may be enhanced via medium access control (MAC) techniques that consider its unique characteristics. Specifically, we study the performance of Aloha-based protocols in underwater networks, and propose two enhanced schemes, namely, Aloha with collision avoidance (Aloha-CA), and Aloha with advance notification (Aloha-AN), which are capable of using the long propagation delays to their advantage. Simulation results have shown that both schemes can boost the throughput by reducing the number of collisions, and, for the case of Aloha-AN, also by significantly reducing the number of unproductive transmissions.