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127
Data mules: Modeling a threetier architecture for sparse sensor networks
 IN IEEE SNPA WORKSHOP
, 2003
"... Abstract — This paper presents and analyzes an architecture that exploits the serendipitous movement of mobile agents in an environment to collect sensor data in sparse sensor networks. The mobile entities, called MULEs, pick up data from sensors when in close range, buffer it, and drop off the data ..."
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Cited by 324 (6 self)
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Abstract — This paper presents and analyzes an architecture that exploits the serendipitous movement of mobile agents in an environment to collect sensor data in sparse sensor networks. The mobile entities, called MULEs, pick up data from sensors when in close range, buffer it, and drop off the data to wired access points when in proximity. This leads to substantial power savings at the sensors as they only have to transmit over a short range. Detailed performance analysis is presented based on a simple model of the system incorporating key system variables such as number of MULEs, sensors and access points. The performance metrics observed are the data success rate (the fraction of generated data that reaches the access points) and the required buffer capacities on the sensors and the MULEs. The modeling along with simulation results can be used for further analysis and provide certain guidelines for deployment of such systems. I.
Spray and Wait: An Efficient Routing Scheme for Intermittently Connected Mobile Networks
 SIGCOMM'05
, 2005
"... Intermittently connected mobile networks are sparse wireless networks where most of the time there does not exist a complete path from the source to the destination. These networks ..."
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Cited by 258 (9 self)
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Intermittently connected mobile networks are sparse wireless networks where most of the time there does not exist a complete path from the source to the destination. These networks
WorstCase Optimal and AverageCase Efficient Geometric AdHoc Routing
, 2003
"... In this paper we present GOAFR, a new geometric adhoc routing algorithm combining greedy and face routing. We evaluate this algorithm by both rigorous analysis and comprehensive simulation. GOAFR is the first adhoc algorithm to be both asymptotically optimal and averagecase e#cient. For our simul ..."
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Cited by 180 (13 self)
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In this paper we present GOAFR, a new geometric adhoc routing algorithm combining greedy and face routing. We evaluate this algorithm by both rigorous analysis and comprehensive simulation. GOAFR is the first adhoc algorithm to be both asymptotically optimal and averagecase e#cient. For our simulations we identify a network density range critical for any routing algorithm. We study a dozen of routing algorithms and show that GOAFR outperforms other prominent algorithms, such as GPSR or AFR.
Efficient routing in intermittently connected mobile networks: The multiplecopy case
, 2008
"... Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that follow this model, for example, wildlife tracking sensor networks, military networks, vehicular ad hoc net ..."
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Cited by 149 (17 self)
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Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that follow this model, for example, wildlife tracking sensor networks, military networks, vehicular ad hoc networks, etc. In this context, conventional routing schemes fail, because they try to establish complete endtoend paths, before any data is sent. To deal with such networks researchers have suggested to use floodingbased routing schemes. While floodingbased schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention which can significantly degrade their performance. Furthermore, proposed efforts to reduce the overhead of floodingbased schemes have often been plagued by large delays. With this in mind, we introduce a new family of routing schemes that “spray ” a few message copies into the network, and then route each copy independently towards the destination. We show that, if carefully designed, spray routing not only performs significantly fewer transmissions per message, but also has lower average delivery delays than existing schemes; furthermore, it is highly scalable and retains good performance under a large range of scenarios. Finally, we use our theoretical framework proposed in our 2004 paper to analyze the performance of spray routing. We also use this theory to show how to choose the number of copies to be sprayed and how to optimally distribute these copies to relays.
Probabilistic Broadcast for Flooding in Wireless Mobile Ad hoc Networks
, 2002
"... Although far from optimal, flooding is an indispensable message dissemination technique for networkwide broadcast within mobile ad hoc networks (MANETs). As such, the plain flooding algorithm provokes a high number of unnecessary packet rebroadcasts, causing contention, packet collisions and ult ..."
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Cited by 129 (1 self)
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Although far from optimal, flooding is an indispensable message dissemination technique for networkwide broadcast within mobile ad hoc networks (MANETs). As such, the plain flooding algorithm provokes a high number of unnecessary packet rebroadcasts, causing contention, packet collisions and ultimately wasting precious limited bandwidth. Studies have been undertaken to optimize flooding using a deterministic approach. Because of the highly dynamic and mobile characteristics of MANETs, probabilistic algorithms may be better suited. We explore the phase transition phenomenon observed in percolation theory and random graphs as a basis for defining probabilistic flooding algorithms. We consider models with and without packet collisions to better understand when phase transition occurs. We show through simulation that in cases of no collision control, probabilistic flooding greatly enhances network performance while significantly reducing broadcast packets in dense networks, although phase transition is not observed.
On the Capacity of Hybrid Wireless Networks
, 2003
"... We study the throughput capacity of hybrid wireless networks. A hybrid network is formed by placing a sparse network of base stations in an ad hoc network. These base stations are assumed to be connected by a highbandwidth wired network and act as relays for wireless nodes. They are not data source ..."
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Cited by 119 (3 self)
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We study the throughput capacity of hybrid wireless networks. A hybrid network is formed by placing a sparse network of base stations in an ad hoc network. These base stations are assumed to be connected by a highbandwidth wired network and act as relays for wireless nodes. They are not data sources nor data receivers. Hybrid networks present a tradeoff between traditional cellular networks and pure ad hoc networks in that data may be forwarded in a multihop fashion or through the infrastructure. It has been shown that the capacity of a random ad hoc network does not scale well with the number of nodes in the system [1]. In this work, we consider two different routing strategies and study the scaling behavior of the throughput capacity of a hybrid network. Analytical expressions of the throughput capacity are obtained. For a hybrid network of n nodes and m base stations, the results show that if m grows asymptotically slower than # n, the benefit of adding base stations on capacity is insignificant. However, if m grows faster than # n, the throughput capacity increases linearly with the number of base stations, providing an effective improvement over a pure ad hoc network. Therefore, in order to achieve nonnegligible capacity gain, the investment in the wired infrastructure should be high enough.
Impact of Interferences on Connectivity in Ad Hoc Networks
 in Proc. IEEE INFOCOM
, 2003
"... We study the impact of interferences on the connectivity of largescale adhoc networks, using percolation theory. We assume that a bidirectional connection can be set up between two nodes if the signal to noise ratio at the receiver is larger than some threshold. The noise is the sum of the contri ..."
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Cited by 115 (13 self)
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We study the impact of interferences on the connectivity of largescale adhoc networks, using percolation theory. We assume that a bidirectional connection can be set up between two nodes if the signal to noise ratio at the receiver is larger than some threshold. The noise is the sum of the contribution of interferences from all other nodes, weighted by a coefficient gamma, and of a background noise. We find that there is a critical value of gamma above which the network is made of disconnected clusters of nodes. We also prove that if gamma is non zero but small enough, there exist node spatial densities for which the network contains a large (theoretically infinite) cluster of nodes, enabling distant nodes to communicate in multiple hops. Since small values of gamma cannot be achieved without efficient CDMA codes, we investigate the use of a very simple TDMA scheme, where nodes can emit only every nth time slot. We show qualitatively that it even achieves a better connectivity than the previous system with a parameter gamma/n.
The Critical Transmitting Range for Connectivity in Sparse Wireless Ad Hoc Networks
, 2003
"... In this paper, we analyze the critical transmitting range for connectivity in wireless ad hoc networks. More specifically, we consider the following problem: assume n nodes, each capable of communicating with nodes within a radius of r, are randomly and uniformly distributed in a ddimensional re ..."
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Cited by 100 (12 self)
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In this paper, we analyze the critical transmitting range for connectivity in wireless ad hoc networks. More specifically, we consider the following problem: assume n nodes, each capable of communicating with nodes within a radius of r, are randomly and uniformly distributed in a ddimensional region with a side of length l; how large must the transmitting range r be to ensure that the resulting network is connected with high probability? First, we consider this problem for stationary networks, and we provide tight upper and lower bounds on the critical transmitting range for onedimensional networks, and nontight bounds for two and threedimensional networks. Due to the presence of the geometric parameter l in the model, our results can be applied to dense as well as sparse ad hoc networks, contrary to existing theoretical results that apply only to dense networks. We also investigate several related questions through extensive simulations. First, we evaluate the relationship between the critical transmitting range and the minimum transmitting range that ensures formation of a connected component containing a large fraction (e.g. 90%) of the nodes. Then, we consider the mobile version of the
A MicroPayment Scheme Encouraging Collaboration in MultiHop Cellular Networks
, 2003
"... We propose a micropayment scheme for multihop cellular networks that encourages collaboration in packet forwarding by letting users benefit from relaying others' packets. At the same time as proposing mechanisms for detecting and rewarding collaboration, we introduce appropriate mechanisms for ..."
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Cited by 98 (8 self)
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We propose a micropayment scheme for multihop cellular networks that encourages collaboration in packet forwarding by letting users benefit from relaying others' packets. At the same time as proposing mechanisms for detecting and rewarding collaboration, we introduce appropriate mechanisms for detecting and punishing various forms of abuse. We show that the resulting scheme  which is exceptionally lightweight  makes collaboration rational and cheating undesirable.
MDDV: A MobilityCentric Data Dissemination Algorithm . . .
, 2004
"... There has been increasing interest in the exploitation of advances in information technology in surface transportation systems. One trend is to exploit onboard sensing, computing and communication capabilities in vehicles, e.g., to augment and enhance existing intelligent transportation systems. A ..."
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Cited by 91 (1 self)
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There has been increasing interest in the exploitation of advances in information technology in surface transportation systems. One trend is to exploit onboard sensing, computing and communication capabilities in vehicles, e.g., to augment and enhance existing intelligent transportation systems. A natural approach is to use vehicletovehicle communications to disseminate information. In this paper, we propose MDDV, a mobilitycentric approach for data dissemination in vehicular networks designed to operate efficiently and reliably despite the highly mobile, partitioned nature of these networks. MDDV is designed to exploit vehicle mobility for data dissemination, and combines the idea of opportunistic forwarding, trajectory based forwarding and geographical forwarding. We develop a generic mobile computing approach for designing localized algorithms in vehicular networks. Vehicles perform local operations based on their own knowledge while they collectively achieve a global behavior. We evaluate the performance of the MDDV algorithm using realistic simulation of the vehicle traffic in Atlanta area.