Route Update and Repair in WSNs

In WSNs, the multihop routes between sensors and sinks suffer breakage or damage because of the moving targets and sinks, or power exhaustion of some sensors. Flooding based routing protocol use broadcast omni-directionally to route discovery or rediscovery packet, It causes significant communication overhead. Query Localization (QL) protocol limits the broadcast of route rediscovery packet within the local region of the old route.
In this paper, the authors propose to update the route by using the information of old route, in the same time, select a new route unnecessary overlapping to the old route.

A sensor network generally comprises a large number of sensors, some relay devices , and a few data collectors. Sensors are , which responsible for generating and reporting sensor data, called “source” .Data collectors are called “sinks”.

Proactive or reactive routing protocols can be used to establish multihop routes between sources and sinks on network dynamics.

one problem of Ad Hoc On Demand Distance Vector (AODV) is that directional information provided by the old route is not used. route Request Packet (RRQ)s are always broadcast omni0directionally.

we can find a brief explanation about AODV and Query Localization (QL) in this paper.

The authors propose an Efficient Route Update Protocol (ERUP) to conduct route rediscovery only in the visinage of existing damaged route. In their protocol, the route update process is divided to two step : first, the nodes along the old route braodcast locally a Route Discovery Region (RDR) packet to define the spreading area of Route Request (RRQ) packet, then a RRQ packet is released from the source or the upstream node of the broken link/node to discover new routes to the sink. Only nodes within the route discovery region can rebroadcast the RRQ.

Route Dynamics In Wireless Sensor Networks

Three kinds of route dynamcis :
a. Endpoint (Sink and Target Mobility)
Although the movement some sinks is caused by unexpected external forces, many sinks do move intentionally by themselves. for example on vehicles systems, such as planes, tanks. the sinks change their positions for better communication channels, safety,etc.in other reasons are keep moving around to prevent their neighbour from power exhausting quickly.

b. Death of Individual Sensors
some sensors deployed in hostile environment or dangerous area, most sensors can not be attended frequently. some sensors may failure since battery exhaustion, channel jamming, etc. It need detour the problematic sensors via their working neighbors to solve these problems.

c. Route-wide power depletion

ERUP divides the route update process to two steps : definition of route discovery region and discovery of new routes within the region.

Simulation
They evaluate and compare perdormance of ERUP with expanding ring search of AODV (ERS-AODV) and QL, they implement ERUP in OPNET 7.0 and the MAC layer of ERUP is 802.11 WLAN model provided by OPNET network simulation package.

Scenarios :

– Effect of Route Size and Network Density
– Effect of speed
– Effect of number of source on Data Delivery

Reference :
Route Update and Repair in Wireless Sensor Networks
Xuhui HU, Yong Liu, Myung J.Lee, Tarek N, Saadawi
City University of New York

Note : This resume is created for self-learning only. Author and Publisher hold copyrights

Paper Predator Jutsu [Mode On] – Searching Research Idea

February 15 2008,
Taipei City
High Speed Network Lab

Udin Harun

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