28-04-2011, 11:24 AM
Presented By
SIVARAM CHINTHALA
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Performance evaluation of EAR routing protocol for fixed power sensor networks
ABSTRACT
Sensor networks are plagued by the problems of interference to wireless communication from environmental noise, node failure and energy-constrained nodes. Routing protocols have to overcome these challenges to achieve robustness in message delivery while expending minimum energy. In this paper, i propose an efficient and reliable (EAR) routing protocol.
Implementation
How do WSNs route data?
Introduction to EAR
Several Existing route protocols in fixed power and multi hob WSN’s use shortest path routing. The environment is also unpredictable and often disrupts operations.
As such routing protocols must ensure that the WSN can reconfigure, be energy efficient and resilient to failures.
With this issues in mind we propose an efficient and reliable protocol that routes messages to one or more hubs for data aggregations
AnEfficient and Reliable Routing Protocol(EAR)
for fixed power sensor networks
Here we takes into account
expected path length
waited combination distance traversed
energy level
page link transmission success history
To dynamically determine and maintain the best routes
Design of EAR
It may be divided into three phases
set up phase
route selection phase
data disseminations
Set Up Phase
In this phase the nodes are going to be created
A node may store more than one route to the hub.
A route in the routing table is indexed using the next hop nodes ID.
A node keeps only one route entry for a neighbor that has a route to the hub even though that neighbor could have multiple routes to the hub.
For each route entry in the route table, only the best route is stored
The selection of the best route is described in the route selection phase
Route Selection Phase
Here we are selecting appropriate routing path based on a page link score metric
LinkScore = PE X WE + PT X WT
Where PE : Energy level of the next hop node (0.0 to 100.0)
WE : Assigned weight for PE (0.0 to 1.0).
PT : Transmission Success rate (0.0 to 100.0)
WT : Assumed Weight for PT (0.0 to 1.0)
Illustration of forwarding based on LinkScore metric
DATA DISSEMINATION
Sensor node generate RPT packets at periodic intervals or sleep, weighting for some event to happen
An RPT packet contains information two phase in its header.
ExpPathLen and NumHopTraversed
ExpPathLen: NH X α, where 0.0 < α < 1.0
Where NH is the no. of hops form this node to the hub for the route selected.
NumHopTraversed : It is the distance a packet has traversed and is initialized as 0.
Route Update
Sensors node’s continually update “best” routes in the routing table
Instead of explicit control packets, EAR uses a handshaking mechanism at the MAC layer.
Route information is piggybacked on to both RTS and CTS packets.
Hence utilize RTS and CTS handshaking instead of separate DATA-ACK would result in more current route information for a node.
Illustration of Route Update
Set up phase
Route Selection Phase
Final Route
Packet Delivery Ratio Vs No. of Nodes