Presentation on theme: "A Distributed Algorithm for the Dead End Problem of Location Based Routing in Sensor Networks Le Zou, Mi Lu, Zixiang Xiong, Department of Electrical Engineering,"— Presentation transcript:
A Distributed Algorithm for the Dead End Problem of Location Based Routing in Sensor Networks Le Zou, Mi Lu, Zixiang Xiong, Department of Electrical Engineering, Texas A&M University IEEE Transactions,Vehicular Technology 2005
Outline Introduction Network Model The PAGER (partial-partition avoiding geographic routing) Algorithm Simulation Conclusions
Introduction Base Station Sensor nodes Sensor nodes forward data packets to BS in a multihop manner
Introduction Base Station The dead end problem x y Greedy forwarding z g Concave Node: distance(x,BS) < distance(y,BS ) ∀ y ∈ N(x),
Network Model A number of sensor nodes randomly deployed on an unobstructed two-dimensional sensing field with a BS. All sensor nodes within communication range r The BS is located either adjacent to the sensing field or inside it Each node knows the location information of the BS.
The PAGER Algorithm The Shadow Spread Phase Divides a connected graph into subgraphs originated from concave nodes The Cost Spread Phase Establishes paths on a given subgraph obtained in the first phase
The Shadow Spread Phase Base Station A B C D E F concave node
The Shadow Spread Phase Base Station A B C D E F shadow node bright nodes Shadow Area Bright Area
The Shadow Spread Phase Nodes exchange information by means of periodically broadcasting beacon messages beacon(status, location) the shadow spread phase converges in n rounds in terms of beacon broadcast interval B
The Cost Spread Phase 5 12 7 16 20 Base Station 18 8 15 16 20 19 23 A B C D E F Euclidian distance to the BS 19+∆ ∆ should be set to the average Euclidean distance between neighboring sensor nodes ∆ is set to 3 in this example 22
The Cost Spread Phase 5 12 7 16 20 Base Station 18 8 15 16 20 19 23 A B C D E F 22+∆ 22 25
The Cost Spread Phase 5 12 7 16 20 Base Station 18 8 15 16 20 19 23 A B C D E F 23+∆ 22 25 26
The Cost Spread Phase 5 12 7 16 20 Base Station 18 8 15 16 20 19 23 A B C D E F 26+∆ 26 25 22 29
The Cost Spread Phase Once the status of a sensor node turns from bright to shadow, the cost spread phase can be triggered on that node immediately The convergence length of the cost spread algorithm in the whole sensor network is only associated with the maximum size of these shadow areas
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