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169
Understanding spatio-temporal uncertainty in medium access with aloha protocols
- In Proceedings of the Second ACM International Workshop on UnderWater Networks (WUWNet
, 2007
"... The goal of this paper is to gain deep understanding of how location-dependent propagation latency affects medium access control (MAC) by using ALOHA as a case study. MAC protocols in underwater acoustic networks suffer from latency that is five orders-of-magnitude larger than that in radio networks ..."
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Cited by 34 (9 self)
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The goal of this paper is to gain deep understanding of how location-dependent propagation latency affects medium access control (MAC) by using ALOHA as a case study. MAC protocols in underwater acoustic networks suffer from latency that is five orders-of-magnitude larger than that in radio networks. Existing work on analyzing MAC throughput in RF networks, where the propagation latency is negligible, generally makes assumptions that render propagation latency irrelevant. As a result, only transmit time is considered as being uncertain in contention-based protocols. We introduce the spatial dimension of uncertainty that is inherent to varying locations of transmitters, resulting in unequal propagation latency to a receiver, where collision occurs. We show through simulation that the benefit of synchronization in slotted ALOHA is lost due to such latency. We propose a modification that adds guard bands to transmission slots to handle spatial uncertainty. We then perform simulation and first order analysis on this modified MAC to find its optimal operating parameters. 1
Focused beam routing protocol for underwater acoustic,” in
- Proc. of ACM WUWNeT,
, 2008
"... ABSTRACT Multi-hop transmission is considered for large coverage areas in bandwidth-limited underwater acoustic networks. In this paper, we present a scalable routing technique based on location information, and optimized for minimum energy per bit consumption. The proposed Focused Beam Routing (FB ..."
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Cited by 34 (8 self)
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ABSTRACT Multi-hop transmission is considered for large coverage areas in bandwidth-limited underwater acoustic networks. In this paper, we present a scalable routing technique based on location information, and optimized for minimum energy per bit consumption. The proposed Focused Beam Routing (FBR) protocol is suitable for networks containing both static and mobile nodes, which are not necessarily synchronized to a global clock. A source node must be aware of its own location and the location of its final destination, but not those of other nodes. The FBR protocol can be defined as a cross-layer approach, in which the routing protocol, the medium access control and the physical layer functionalities are tightly coupled by power control. It can be described as a distributed algorithm, in which a route is dynamically established as the data packet traverses the network towards its final destination. The selection of the next relay is made at each step of the path after suitable candidates have proposed themselves. The system performance is measured in terms of energy per bit consumption and average packet end-to-end delay. The results are compared to those obtained using pre-established routes, defined via Dijkstra's algorithm for minimal power consumption. It is shown that the protocol's performance is close to the ideal case, as the additional burden of dynamic route discovery is minimal.
Underwater sensor networks: applications, advances, and challenges
"... Subject collections Email alerting service This article cites 25 articles ..."
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Cited by 27 (0 self)
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Subject collections Email alerting service This article cites 25 articles
Prospects and Problems of Wireless Communication for Underwater Sensor Networks
"... This paper reviews the physical fundamentals and engineering implementations for efficient information exchange via wireless communication using physical waves as the carrier among nodes in an underwater sensor network. The physical waves under discussion include sound, radio, and light. We first pr ..."
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Cited by 24 (5 self)
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This paper reviews the physical fundamentals and engineering implementations for efficient information exchange via wireless communication using physical waves as the carrier among nodes in an underwater sensor network. The physical waves under discussion include sound, radio, and light. We first present the fundamental physics of different waves; then we discuss and compare the pros and cons for adopting different communication carriers (acoustic, radio, and optical) based on the fundamental first principles of physics and engineering practice. The discussions are mainly targeted at underwater sensor networks with densely deployed nodes. Based on the comparison study, we make recommendations for the selection of communication carriers for underwater sensor networks with engineering countermeasures that can possibly enhance the communication efficiency in specified underwater environments.
Underwater acoustic communications: Design considerations on the physical layer
- Fifth Annual Conference on Wireless on Demand Network Systems and Services
, 2008
"... Abstract—Acoustic propagation is characterized by three major factors: attenuation that depends on the signal frequency, multipath propagation, and low speed of sound (1500 m/s). The channel has a sparse impulse response, where each physical path acts as a time-varying low-pass filter, and motion in ..."
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Cited by 23 (6 self)
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Abstract—Acoustic propagation is characterized by three major factors: attenuation that depends on the signal frequency, multipath propagation, and low speed of sound (1500 m/s). The channel has a sparse impulse response, where each physical path acts as a time-varying low-pass filter, and motion introduces additional Doppler spreading and shifting. Because propagation is best supported at low frequencies, acoustic communication systems are inherently wideband. The way in which these facts influence the design of signal processing methods is considered for single-carrier and multi-carrier systems. Moreover, the facts that the available bandwidth and transmission power depend heavily on the distance, and that channel latency is high, bear important implications on the design of network architectures and related protocols. I.
Three-dimensional and two-dimensional deployment analysis for . . .
- AD HOC NETWORKS
, 2008
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Network Coding Schemes for Underwater Networks: The Benefits of Implicit Acknowledgement
- In Proc. WUWnet ’07
"... Underwater acoustic communications are characterized by a long propagation delay and limited bandwidth. Power consumption is an additional constraint for underwater networks. Network layer schemes for that minimize both transmission time and power consumption are thus of interest. Conventional routi ..."
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Cited by 16 (8 self)
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Underwater acoustic communications are characterized by a long propagation delay and limited bandwidth. Power consumption is an additional constraint for underwater networks. Network layer schemes for that minimize both transmission time and power consumption are thus of interest. Conventional routing schemes have limitations in both power consumption and delay performance. Application of network coding schemes in rateless fashion results in better delay performance; however, power consumption is greater than for most routing schemes when the network is lightly loaded. This paper proposes a new method for network coding that relies on implicit acknowledgements to improve power consumption performance. Numerical results demonstrate superior performance of the scheme proposed. The method is also applicable to other wireless channels.
Energy Efficient Multi-Path Communication for Time-Critical Applications in Underwater Sensor Networks
, 2008
"... Due to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for time-critical applications in an energy-efficient way. On the one hand, traditional retransmission-upon-failure usually introduces very large end-end delay, thus i ..."
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Cited by 16 (1 self)
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Due to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for time-critical applications in an energy-efficient way. On the one hand, traditional retransmission-upon-failure usually introduces very large end-end delay, thus is not proper for time-critical services. On the other hand, common approaches without retransmission consume lots of energy. In this paper, we propose a new multi-path power-control transmission (MPT) scheme, which can guarantee certain end-to-end packet error rate while achieving a good balance between the overall energy efficiency and the end-to-end packet delay. MPT smartly combines power control with multi-path routing and packet combining at the destination. With carefully designed power control strategies, MPT consumes much less energy than the conventional onepath transmission scheme without retransmission. Besides, since no hop-by-hop retransmission is allowed, MPT introduces much shorter delay than the traditional one-path scheme with retransmission. We conduct extensive simulations to evaluate the performance of MPT. Our results show that MPT is highly energy efficient with low end-to-end packet delays.
Statistical characterization and capacity of shallow water acoustic channels
- Proc. IEEE Oceans’09 Conference
, 2009
"... Abstract — This paper focuses on statistical characterization and capacity evaluation of shallow water acoustic communications channels. Wideband single-carrier and multi-carrier probe signals are employed to measure the time-varying channel response, and to estimate its statistical properties that ..."
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Cited by 15 (7 self)
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Abstract — This paper focuses on statistical characterization and capacity evaluation of shallow water acoustic communications channels. Wideband single-carrier and multi-carrier probe signals are employed to measure the time-varying channel response, and to estimate its statistical properties that play an important role in the design of bandwidth-efficient and powerefficient communication systems. To assess the capacity of an underwater acoustic channel, we first assess the probability density functions that model the signal fading. Rician fading is found to provide a good match for the experimental data collected in the Pacific Ocean during the summer 2008 Kauai acoustic communications experiment (KAM’08). This model is used to evaluate the ergodic channel capacity and the related bandwidth efficiency for both single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems. I.
A Cross-layer Communication Solution for Multimedia Applications in Underwater Acoustic Sensor Networks
"... Underwater multimedia acoustic sensor networks will enable new underwater applications such as multimedia coastal and tactical surveillance, undersea explorations, picture and video acquisition and classification, and disaster prevention. Because of the different requirements of these applications, ..."
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Cited by 15 (7 self)
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Underwater multimedia acoustic sensor networks will enable new underwater applications such as multimedia coastal and tactical surveillance, undersea explorations, picture and video acquisition and classification, and disaster prevention. Because of the different requirements of these applications, it is needed to provide efficient differentiated-service support to delay-sensitive and delaytolerant data traffic as well as to loss-sensitive and losstolerant traffic. The objective of this paper is twofold: 1) explore the interactions of different underwater communication functionalities such as modulation, forward error correction, medium access control and routing, and 2) develop a distributed cross-layer solution integrating specialized communication functionalities that cooperate to allow multiple devices to efficiently and fairly share the bandwidthlimited high-delay underwater acoustic medium. 1
