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ChordPlus： a scalable, decentralized object location and routing algorithm

Journal of Systems Engineering and Electronics 2004年第4期15卷 772-779,787页

作者： BaiHaihuan JiangJunjie WangWeinong ComputerScience&EngineeringDepartment ShanghaiJiaotongUniversityShanghai200030P.R.China

Object looation is a fundamental problem in distributed system such as grid computing and peer-to-peer environment. Chord is one of the typical scalable object looation algorithms for peer-to-peer network. The simplicity, provable correctness and provable performance of Chord make it an attractive option for distributed lookup. However its lookup performance is not satisfying. Based on the decentralized object looation mathematical model. This paper proposes ChordPlus, an improved Chord algorithm, by enlarging dimension size of space M ( M = 2 in Chord) and utilizing data redundancy technology. ChordPlus is a scalable, fault-tolerant, completely decentralized and self-organizing object looation and routing algorithm for overlay network. Results from theoretical analysis and simulation experiments show that increasing the dimension size of space or neighborhood set length can enhance the routing performance of ChordPlus. In a simulation network with 5 000 nodes, the average muting path length of ChordPlus is only as many as half that of Chord algorithm.

关键词： Routing peer to peer computing Algorithm design and analysis Mathematical model Complexity theory Redundancy Object recognition

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A Novel Location-Free Greedy Forward Algorithm for Wireless Sensor Networks

A Novel Location-Free Greedy Forward Algorithm for Wireless ...

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Azzedine Boukerche Horacio A.B.F.Oliveira Eduardo F.Nakamura Antonio A.F.Loureiro PARADISE Research Laboratory SITE-University of Ottawa Department of Computer Science-Federal University of Minas Gerais

In this work,we propose a new Greedy Forward algorithm to be used in Wireless Sensor Networks （WSNs） routing protocols.Differently from current Greedy Forward algorithms,which depend on the position information of nodes,our approach uses only the Received Signal Strength Indicator （RSSI） of exchanged packets.Since nodes’ position are usually computed based on three or more distance estimations （commonly by means of RSSI measurements） and the positions of beacon nodes （which have inaccuracies by themselves）,by using only RSSI measurements,we should achieve better results.Based on this observation,we propose the RSSR （Received Signal Strength Routing） algorithm with two variants:RSSR Election and RSSR Selection.In the RSSR Election,the next hop is dynamically elected at each step and no packets are required for the routing task.In the RSSR Selection,neighbors exchange packets with RSSI information and the next hop of the packet is then selected from a routing table at each step.Our results indicate clearly that the proposed algorithms have all the benefits of a Greedy Forward algorithm but with better performance and without requiring positions information.

关键词： Wireless sensor networks Nominations and elections peer to peer computing Computer science Routing protocols Position measurement Monitoring Temperature sensors Scalability Energy efficiency

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Mutual Information and Energy Tradeoff in Correlated Wireless Sensor Networks

Mutual Information and Energy Tradeoff in Correlated Wireles...

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Laxminarayana S Pillutla Vikram Krishnamurthy Department of Electrical and Computer Engineering The University of British Columbia 2332 Main Mall VancouverBC V6T1Z4Canada

We consider comparison of Mutual Information （MI）-Energy tradeoff in correlated wireless sensor network （WSN） for cooperative multiple input and multiple output （MIMO） and non-cooperative （referred to as single input and single output （SISO）） transmission schemes.Our numerical results indicate that for short distances SISO schemes achieve better MI-Energy tradeoff than the cooperative MIMO schemes,while for long distances the cooperative MIMO schemes achieve better MI-Energy tradeoff.We next consider the issue of sensor placement in a correlated WSN.Specifically,we prove that the spacing between nodes to maximize MI is in general an increasing function of observation SNR.From this structural result,we conclude that at high SNR,the various stages of the WSN can be separated by relatively large distances than at low SNR.

关键词： Mutual information Wireless sensor networks MIMO peer to peer computing Energy consumption Communications Society Batteries Encoding Energy efficiency Source coding

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On the Use of Multiple Antennas to Reduce MAC Layer Coordination in Ad Hoc Networks

On the Use of Multiple Antennas to Reduce MAC Layer Coordina...

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Raymond H.Y.Louie Matthew R.McKay Iain B.Collings Telecommunications Lab School of Electrical and Information EngineeringUniversity of SydneyAustralia Wireless Technologies Laboratory ICT CentreCSIROSydneyAustralia Department of Electronic and Computer Engineering Hong Kong University of Science and TechnologyHong Kong

This paper investigates an important tradeoff in wireless ad hoc networks concerning the allocation of resources to the PHY and MAC layers.We compare two approaches:One which employs a non-coordinated slotted ALOHA MAC with multi-antenna PHY,and one which employs a tightly coordinated MAC and single-antenna PHY.For both cases,we derive new closed-form throughput expressions.Based on these,we show that using simple slotted ALOHA in conjunction with multiple antennas can provide a higher throughput than fully coordinated access protocols in various practical scenarios.Our results are confirmed through comparison with Monte Carlo simulations.

关键词： Ad hoc networks Physical layer Throughput Media Access Protocol peer to peer computing Interference Slot antennas Time division multiple access Array signal processing Paper technology

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Energy Conservation in Reliable Wireless Sensor Networks

Energy Conservation in Reliable Wireless Sensor Networks

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Fatma Bouabdallah Nizar Bouabdallah Raouf Boutaba INRIA-IRISA Campus de Beaulieu 35042RennesFrance School of Computer Science University of Waterloo

Energy-efficiency is one of the major concerns in wireless sensor networks since it impacts the network lifetime.In this paper,we investigate the relationship between sensor network performance,particularly its lifetime,and the number of active reporting nodes N by using both analytical and simulation approaches.We first demonstrate that decreasing the number of reporting nodes increases the number of reports that need to be sent to the sink,in order to achieve the desired information reliability regarding the detected event.On the other hand,we show that reducing the number of reporting nodes alleviates the energy wastage due to collisions.Based on this tradeoff,and as a main contribution,we derive the optimal number of reporting nodes N opt energy that minimizes the energy consumed to report reliably the occurrence of an event.In other words,we prove that limiting the reporting tasks of a detected event to a small subset of sensor nodes （i.e.,N opt energy）,instead of using all the sensor nodes in the event area,enables significant energy conservation.

关键词： Energy conservation Wireless sensor networks peer to peer computing Event detection Energy consumption Energy efficiency Media Access Protocol Routing protocols Communications Society Computer network reliability

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Performance Analysis of Distributed Spatial Diversity with Selection Combining

Performance Analysis of Distributed Spatial Diversity with S...

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Jeremiah Hu Norman C.Beaulieu iCORE Wireless Communications Laboratory University of Alberta 2nd Floor ECERF Building EdmontonAlbertaCanada T6G 2V4

Cooperative diversity,where multiple communication nodes collaborate to exploit independent signal replicas that are combined at the destination has been proposed.Practical diversity receivers often employ simple combining techniques especially if comparable performance to more complex optimum combining can be achieved.The performances of cooperative diversity systems that use selection combining are investigated.In particular,we consider decode-and-forward and amplifyand-forward relaying protocols.Closed-form expressions for the outage probability of systems with an arbitrary number of relay nodes are derived.By comparing the performance of a system that uses selection combining to one that uses optimum maximal ratio combining,the trade-off between performance and receiver complexity is determined.

关键词： Diversity reception Performance analysis Relays Closed-form solution Wireless communication Decoding Protocols Cultural differences peer to peer computing Collaboration

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Multi-channel Multi-interface MAC Protocol in Wireless Ad Hoc Networks

Multi-channel Multi-interface MAC Protocol in Wireless Ad Ho...

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Eunsook Shim Seunghoon Baek Joungsik Kim Dongkyun Kim Department of Computer Engineering Kyungpook National University Graduate School of Electrical Engineering and Computer Science Kyungpook National University Electronics and Telecommunications Research Institute

In wireless ad hoc networks,utilizing multiple interfaces as well as multiple channels at MAC layer is known as one of key techniques to improve network capacity.Since the existing multi-channel MAC protocols like MMAC and SSCH assume that a single interface is used,a protocol such as HMCP was proposed in order to make the best use of multiple interfaces.However,a fixed specific channel is assigned to an interface in HMCP.In addition,HMCP requires one interface to accomplish an exclusive purpose of either transmission or reception.To address these shortcomings,we propose a multi-channel multi-interface MAC （MM-MAC） protocol,which dynamically assigns channels to each interface of the nodes and reserves the transmission times of nodes on these selected channels.The scheduled transmission of packets also enables our MM-MAC protocol to reduce the number of channel collisions and the overhead of exchanging control messages.Through extensive study using the ns-2 simulator,we observe that our MM-MAC protocol performs better than the existing protocols such as MMAC and HMCP.

关键词： Media Access Protocol Wireless application protocol Mobile ad hoc networks Scheduling peer to peer computing Throughput Data communication Communications Society Computer interfaces Computer networks

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Spatial Reuse for Practical Scenarios:Iterative Power Adjustment from Distributed Contour Estimation and Propagation

Spatial Reuse for Practical Scenarios:Iterative Power Adjust...

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2008 IEEE International Conference on Communications(ICC 2008)

作者： Sofie Pollin Bart Adams Ahmad Bahai University of California Berkeley Interuniversity Micro-Electronics Center Stanford University Katholieke Universiteit Leuven

The number of wireless networks that coexist in space is increasing steeply.To allow coexistence while avoiding interference,it becomes important to properly characterize the propagation contour where the received power of wireless transmitters reaches a certain threshold.Detailed channel modeling taking into account the specificities of typical urban scenarios is however a very complex task.Thanks to the widespread use of wireless access technology,it becomes feasible to use network nodes to estimate and communicate these propagation contours.In this paper,we propose a lightweight practical scheme for local contour estimation of a given transmitter.The local estimate is efficiently propagated to all other secondary transmitters that can then meet interference constraints optimally,i.e.,without having to consider large safety margins that limit spatial reuse gains.This optimality is obtained through iterative power control based on true propagation contour distances and local pathloss estimates.The overhead of the estimation and communication phases is simulated to be close to linear in the number of nodes,so that the solution scales well.The scheme can be used for optimal power control in practical wireless networks,or for the deployment of secondary networks in areas with primary transmitters that should be protected.

关键词： Transmitters Safety Power control Wireless networks Space technology peer to peer computing Optical propagation Interference constraints Wireless sensor networks TV

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