Toward a Packet Duplication Control for

Opportunistic Routing in WSNsGeorgios Z. Papadopoulos, Julien Beaudaux, Antoine Gallais, Periklis Chatzimisios, and Thomas Noel

(University of Strasbourg - France, Norwegian University of Science and Technology – Norway, and Alexander TEI of Thessaloniki - Greece)

In Proceedings of the IEEE Globecom, London, Austin, TX, USA, December 2014

Nov. 24, 2015

Minwoo Joo

(mwjoo@korea.ac.kr)

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Outline

• Introduction

• Problem Statement & Proposed Mechanism

• Performance Evaluation

• Conclusions and Future Work

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Introduction

• Opportunistic Routing• Packets are sent opportunistically (i.e. anycast)

• A data packet is transmitted to the first potential forwarder acknowl-edging the corresponding message

• To save energy, low power listening MAC mechanisms are adopted• where preamble are transmitted (and acknowledged) prior to any data

communication

• By increasing the number of potential forwarders, several neighbors lead to faster (yet multiple) preamble ACKs• Thus, it allows for improved throughput, reduced end-to-end delays

and more balanced energy consumption between nodes

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Introduction

• Redundant Packet Forwarding• A single packet could be received by multiple neighbors due

to their homogenous configurations• e.g., duty-cycle

• This leads to several distinct messages, recursively propa-gated at each hop, and eventually to packet duplication at the sink• Increased traffic and channel occupancy over the entire network

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Introduction

• Potential Deafness• It introduces heterogeneity among nodes to reduce the prob-

ability of having multiple receivers for a single packet

• Nodes dynamically regulate their configurations in localized manner without endangering network disconnection

• Advantages• Improved network performance

• Reduced energy consumption

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Problem Statement & Proposed Mechanism

• Problem Statement: Packet Duplication• In WSNs relying on opportunistic routing, two factors need to

be fulfilled for a single data packet to be received by several neighbors• Two or more nodes have to sample their radio channel while the packet

is being transmitted

• These nodes have to successfully catch the preamble and acknowl-edge it

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Problem Statement & Proposed Mechanism

• Problem Statement: Packet Duplication (Cont’d)• This problem can be formalized by adapting the birthday

paradox• The probability of any other potential forwarder to sample the medium

at the same time slot is given as follows

𝑡𝑂𝑁𝑡𝑖𝑚𝑒 𝑂𝑁𝑡𝑖𝑚𝑒

𝑤𝑎𝑘𝑒−𝑢𝑝 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙

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Problem Statement & Proposed Mechanism

• Problem Statement: Packet Duplication (Cont’d)• is given as the probability of having two or more nodes catch-

ing the preamble at the same time slot

• As shown below, this probability is strongly correlated to both the wake-up interval and the size of the potential receivers set

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Problem Statement & Proposed Mechanism

• Proposed Mechanism: Potential Deafness• This paper introduce the potentiality of deafness in WSN

• The key idea is to adapt a node’s wakeup interval to the local number of potential forwarders

• It is assumed that a gradient protocol is used which generates a routing tree rooted at the sink• Thus, each node can obtain the local number of potential forwarders

by overhearing messages broadcasted during the construction of the routing tree

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Problem Statement & Proposed Mechanism

• Proposed Mechanism: Potential Deafness (Cont’d)• The number of potential forwarders can be used in accor-

dance with application-level performance parameters (e.g., QoS, lifetime, etc.)• to affect each node in the network with a specific wake-up interval

• A multi-objective optimization problem (MOP) is formulated based on these parameters• The solution to this MOP represents the best-suited MAC parameters a

node can be configured with to fulfill all application requirements

• As a result, heterogeneous configurations among the nodes lead to potential deafness• The applicative parameters may change over time for fairness

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Performance Evaluation

• Experimental Setup• Over the Strasbourg platform of the FIT IoT-LAB testbed

• 3D grid of 240 fixed nodes

• TI CC11011 radio chipset and MSP430 micro-controller

• Implementation with X-MAC protocol

• Applicative requirement as a maximal duplication probability of 60%

125𝑚𝑠250𝑚𝑠 500𝑚𝑠

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Performance Evaluation

• Packet Duplication

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Performance Evaluation

• Reliability, Delay, and Energy Consumption

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Conclusions and Future Work

• This paper examines to what extent the auto-adaptive mechanism can mitigate packet duplication in opportunistic routing• The proposed mechanism is based on local configuration at each

node

• The experimental results show that the adaptive mecha-nism achieves better performance in terms of delay, PRR, as well as energy consumption

• The ongoing work consists of further exploring this lead in mobile sensors

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Thank You.Q & A