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520
Revisiting the TTL-based controlled flooding search: Optimality and randomization
- Proceedings of the Tenth Annual International Conference on Mobile Computing and Networks (MobiCom’04
, 2004
"... In this paper we consider the problem of searching for a node or an object (i.e., piece of data, file, etc.) in a large network. Applications of this problem include searching for a destination node in a mobile ad hoc network, querying for a piece of desired data in a wireless sensor network, and se ..."
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Cited by 61 (5 self)
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In this paper we consider the problem of searching for a node or an object (i.e., piece of data, file, etc.) in a large network. Applications of this problem include searching for a destination node in a mobile ad hoc network, querying for a piece of desired data in a wireless sensor network, and searching for a shared file in an unstructured peer-to-peer network. We limit our attention in this study to the class of controlled flooding search strategies where query/search packets are broadcast and propagated in the network until a preset TTL (time-to-live) value carried in the packet expires. Every unsuccessful search attempt results in an increased TTL value (i.e., larger search area) and the same process is repeated. The primary goal of this study is to derive search strategies (i.e., sequences of TTL values) that will minimize the cost of such searches associated with packet transmissions. The main results of this paper are as follows. When the probability distribution of the location of the object is known a priori, we present a dynamic programming formulation with which optimal search strategies can be derived that minimize the expected search cost. We also derive the necessary and sufficient conditions for two very commonly used search strategies to be optimal. When the probability distribution of the location of the object is not known a priori and the object is to minimize the worst-case search cost, we show that the best strategies are randomized strategies, i.e., successive TTL values are chosen from certain probability distributions rather than deterministic values. We show that given any deterministic TTL sequence, there exists a randomized version that has a lower worst-case expected search cost. We also derive an asymptotically (as the network size increases) optimal strategy within a class of randomized strategies.
Location Information Services in Mobile Ad Hoc Networks
- In Proceedings of the IEEE International Conference on Communications (ICC
, 2003
"... In recent years, several position-based routing protocols have been developed for mobile ad hoc networks. Many of these protocols assume a location service is available that provides location information on the nodes in the network. In this chapter, we survey all the proposed location information ..."
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Cited by 61 (7 self)
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In recent years, several position-based routing protocols have been developed for mobile ad hoc networks. Many of these protocols assume a location service is available that provides location information on the nodes in the network. In this chapter, we survey all the proposed location information services that exist in the literature to date. We classify these location information services into three categories: proactive location database systems, proactive location dissemination systems, and reactive location systems.
Localization with mobile anchor points in wireless sensor networks
- IEEE Transactions on Vehicular Technology
, 2005
"... Abstract—Localization is one of the substantial issues in wireless sensor networks. Several approaches, including range-based and range-free, have been proposed to calculate positions for randomly deployed sensor nodes. With specific hardware, the range-based schemes typically achieve high accuracy ..."
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Cited by 54 (0 self)
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Abstract—Localization is one of the substantial issues in wireless sensor networks. Several approaches, including range-based and range-free, have been proposed to calculate positions for randomly deployed sensor nodes. With specific hardware, the range-based schemes typically achieve high accuracy based on either node-tonode distances or angles. On the other hand, the range-free mechanisms support coarse positioning accuracy with the less expense. This paper describes a range-free localization scheme using mobile anchor points. Each anchor point equipped with the GPS moves in the sensing field and broadcasts its current position periodically. The sensor nodes obtaining the information are able to compute their locations. With the scheme, no extra hardware or data communication is needed for the sensor nodes. Moreover, obstacles in the sensing fields can be tolerated. The localization mechanism has been implemented in the network simulator ns-2. The simulation results show that our scheme performed better than other range-free mechanisms. Index Terms—Geometry, localization, mobile anchor points, range-free, wireless sensor networks. I.
ADHOC MAC: New MAC Architecture for Ad Hoc Networks Providing Efficient and Reliable Point-to-Point and Broadcast Services
- Wireless Networks
, 2004
"... Ad-hoc networking, though an attractive solution for many applications, still has many unsolved issues, such as the hiddenterminal problem, flexible and prompt access, QoS provisioning, and efficient broadcast service. In this paper we present a MAC architecture able to solve the above issues in env ..."
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Cited by 53 (10 self)
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Ad-hoc networking, though an attractive solution for many applications, still has many unsolved issues, such as the hiddenterminal problem, flexible and prompt access, QoS provisioning, and efficient broadcast service. In this paper we present a MAC architecture able to solve the above issues in environments with no power consumption limitations, such as networks for inter-vehicle communications. This new architecture is based on a completely distributed access technique, RR-ALOHA, capable of dynamically establishing, for each active terminal in the network, a reliable single-hop broadcast channel on a slotted/framed structure. Though the proposed architecture uses a slotted channel it can be adapted to operate on the physical layer of different standards, including the UMTS Terrestrial Radio Access TDD, and IEEE 802.11. The paper presents the mechanisms that compose the new MAC: the basic RR-ALOHA protocol, an efficient broadcast service and the reservation of point-to-point channels that exploit parallel transmissions. Some basic performance figures are discussed to prove the effectiveness of the protocol.
Dw-mac: a low latency, energy efficient demand-wakeup mac protocol for wireless sensor networks
- Proceedings of the 9th ACM international
, 2008
"... Duty cycling is a widely used mechanism in wireless sensor networks (WSNs) to reduce energy consumption due to idle listening, but this mechanism also introduces additional latency in packet delivery. Several schemes have been proposed to mitigate this latency, but they are mainly optimized for ligh ..."
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Cited by 48 (4 self)
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Duty cycling is a widely used mechanism in wireless sensor networks (WSNs) to reduce energy consumption due to idle listening, but this mechanism also introduces additional latency in packet delivery. Several schemes have been proposed to mitigate this latency, but they are mainly optimized for light traffic loads. A WSN, however, could often experience bursty and high traffic loads, such as due to broadcast or convergecast traffic. In this paper, we present a new MAC protocol, called Demand Wakeup MAC (DW-MAC), that introduces a new low-overhead scheduling algorithm that allows nodes to wake up on demand during the Sleep period of an operational cycle and ensures that data transmissions do not collide at their intended receivers. This demand wakeup adaptively increases effective channel capacity during an operational cycle as traffic load increases, allowing DW-MAC to achieve low delivery latency under a wide range of traffic loads including both unicast and broadcast traffic. We compare DW-MAC with S-MAC (with and without adaptive listening) and with RMAC using ns-2 and show that DW-MAC outperforms these protocols, with increasing benefits as traffic load increases. For example, under high unicast traffic load, DW-MAC reduces delivery latency by 70 % compared to S-MAC and RMAC, and uses only 50 % of the energy consumed with S-MAC with adaptive listening. Under broadcast traffic, DW-MAC reduces latency by more than 50 % on average while maintaining higher energy efficiency.
Efficient flooding in ad hoc networks: a comparative performance study
- in Proceedings of the IEEE International Conference on Communications (ICC
, 2003
"... Abstract — The blind flooding can become very inefficient because of redundant, “superfluous ” forwarding. In fact, superfluous flooding increases link overhead and wireless medium congestion. In a large network, with heavy load, this extra overhead can have severe impact on performance and should b ..."
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Cited by 35 (0 self)
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Abstract — The blind flooding can become very inefficient because of redundant, “superfluous ” forwarding. In fact, superfluous flooding increases link overhead and wireless medium congestion. In a large network, with heavy load, this extra overhead can have severe impact on performance and should be eliminated. Efficient flooding schemes to choose a dominant set of nodes have been recently proposed in ad hoc networks. In this paper, we compare the performance of a set of representative schemes via simulation using as criteria the flooding efficiency and the delivery ratio. I.
Performance analysis of broadcast protocols in ad hoc networks based on self-pruning
- IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS
, 2004
"... Self-pruning is an effective scheme for efficient broadcasting in ad hoc wireless networks. In a self-pruning broadcast protocol, a node may not forward a broadcast packet if a certain self-pruning condition is satisfied based on the neighborhood information. In a static network with an ideal MAC la ..."
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Cited by 34 (0 self)
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Self-pruning is an effective scheme for efficient broadcasting in ad hoc wireless networks. In a self-pruning broadcast protocol, a node may not forward a broadcast packet if a certain self-pruning condition is satisfied based on the neighborhood information. In a static network with an ideal MAC layer, only a subset of nodes forward the broadcast packet and still guarantee the complete network delivery. Various protocols have been proposed with different self-pruning conditions. Recently, a generic selfpruning protocol was proposed by Wu and Dai [21], which combines the strength of previous conditions and is more effective. In this paper, we first propose an enhanced version of the generic protocol, which is more elegant in interpreting existing protocols and has a simpler correctness proof. Then, we evaluate the performance of the family of self-pruning protocols under various network situations with ns2. The objective is to observe the efficiency and reliability of these protocols as a function of network density, congestion, and mobility, and provide a guideline of implementation in the “real world.” Our performance analysis reveals that the protocol reliability is barely affected by packet collision. However, most self-pruning protocols suffer from low delivery ratio in highly mobile networks. We further explore various techniques that improve the delivery ratio and show that both high efficiency and reliability can be achieved in highly mobile networks.
MISTRAL: Efficient flooding in mobile ad-hoc networks
- In Proceedings of the 7th ACM Int’l Symp. on Mobile Ad Hoc Networking and Computing (MobiHoc
, 2006
"... Flooding is an important communication primitive in mobile ad-hoc networks and also serves as a building block for more complex protocols such as routing protocols. In this paper, we propose a novel approach to flooding, which relies on proactive compensation packets periodically broadcast by every ..."
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Cited by 33 (0 self)
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Flooding is an important communication primitive in mobile ad-hoc networks and also serves as a building block for more complex protocols such as routing protocols. In this paper, we propose a novel approach to flooding, which relies on proactive compensation packets periodically broadcast by every node. The compensation packets are constructed from dropped data packets, based on techniques borrowed from forward error correction. Since our approach does not rely on proactive neighbor discovery and network overlays it is resilient to mobility. We evaluate the implementation of Mistral through simulation and compare its performance and overhead to purely probabilistic flooding. Our results show that Mistral achieves a significantly higher node coverage with comparable overhead.
RBP: Robust broadcast propagation in wireless networks
- In Sensys’06
, 2006
"... Varying interference levels make broadcasting an unreliable operation in low-power wireless networks. Many routing and resource discovery protocols depend on flooding (repeated per-node broadcasts) over the network. Unreliability at the broadcast-level can result in either incomplete flooding covera ..."
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Cited by 33 (0 self)
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Varying interference levels make broadcasting an unreliable operation in low-power wireless networks. Many routing and resource discovery protocols depend on flooding (repeated per-node broadcasts) over the network. Unreliability at the broadcast-level can result in either incomplete flooding coverage or excessive re-flooding, making path maintenance either unreliable or expensive. We present RBP, a very simple protocol that bolsters the reliability of broadcasting in such networks. Our protocol requires only local information, and resides as a service between the MAC and network layer, taking information from both. We show that RBP improves reliability while balancing energy efficiency. RBP is based on two principles: First, we exploit network density to achieve near-perfect flooding reliability by requiring moderate (50-70%) broadcast reliability when nodes have many neighbors. Second, we identify areas of sparse connectivity where important links bridge dense clusters of nodes, and strive for guaranteed reliability over those links. We demonstrate, through both testbed experiments and controlled simulations, that this hybrid approach is advantageous to providing nearperfect reliability for flooding with good efficiency. Testbed experiments show 99.8 % reliability with 48 % less overhead than the level of flooding required to get equivalent reliability, suggesting that routing protocols will benefit from RBP.
On mitigating the broadcast storm problem with directional antennas
- Communications, 2003. ICC '03. IEEE International Conference on Publication Date: 1115
, 2003
"... Abstract — Broadcast has been widely used in mobile ad hoc networks (MANETs) as a communication means to disseminate information to all reachable nodes. However, the conventional broadcast scheme that broadcast packets omnidirectionally suffers from several drawbacks: excessive amount of redundant t ..."
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Cited by 32 (0 self)
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Abstract — Broadcast has been widely used in mobile ad hoc networks (MANETs) as a communication means to disseminate information to all reachable nodes. However, the conventional broadcast scheme that broadcast packets omnidirectionally suffers from several drawbacks: excessive amount of redundant traffic, exaggerated interference/contention among neighboring nodes, and limited coverage (as a result of contention/collision). This is termed as the broadcast storm problem in [20]. In this paper, we address this problem in MANETs with the use of directional antennas. We propose three schemes: on/off directional broadcast, relay-node-based directional broadcast and location-based directional broadcast, in the increasing order of implementation complexity. We implement the proposed schemes in QualNet and compare their performances against the conventional broadcast scheme. The simulation results indicate that the proposed schemes outperform the conventional omnidirectional scheme with respect to coverage, latency, and redundancy over a wide spectrum of network topology and node mobility. B I.
