How to Calculate Coverage Reliability in NS2
To calculate the coverage reliability in Network Simulator 2 (NS2), we have to concentrate on stating how consistent the network’s coverage in over time, responsible for metrics like node mobility, energy utilization, communication range and sensor failure. It reflects the probability that a target area or event is reliability covered by one or more nodes through the simulation. Follow the computational guide to measure the coverage reliability in NS2:
Step-by-Step Implementation:
- Define Coverage Reliability Concept:
- Coverage Reliability computes how consistently the area of interest remains covered during the simulation.
- It’s frequently calculated as the ratio of time the area is covered to the entire simulation time.
- Coverage Reliability formula: Coverage Reliability=∑(Time Area is Covered)Total Simulation Time×100\text{Coverage Reliability} = \frac{\sum (\text{Time Area is Covered})}{\text{Total Simulation Time}} \times 100Coverage Reliability=Total Simulation Time∑(Time Area is Covered)×100
- Set Up the Simulation:
- State the region of interest and deploy nodes.
- Configure mobility models (if applicable) and node failure models to simulate real-world dynamics.
- Define the total simulation time and initialize network parameters like node transmission/sensing range.
- TCL Script Setup for Coverage Reliability:
Here’s a simple sample of how to set up nodes and sensing ranges in an NS2 TCL script to prepare for coverage reliability calculation:
# Create Simulator
set ns [new Simulator]
# Define the total simulation time
set totalSimulationTime 1000.0 ;# Total time in seconds
# Create Topography
set topo [new Topography]
$topo load_flatgrid 100 100 ;# Assuming a 100m x 100m area
# Create nodes
set node_(0) [$ns node]
set node_(1) [$ns node]
# Add more nodes as needed
# Assign positions to nodes
$node_(0) set X_ 20
$node_(0) set Y_ 30
$node_(1) set X_ 60
$node_(1) set Y_ 50
# Define the sensing range for coverage (e.g., 30 meters)
set sensingRange 30
# Define mobility models (if applicable)
$ns at 10.0 “$node_(0) setdest 50 70 10” ;# Move node 0 to a new location at time 10s
- Tracking Time-Coverage Events:
- Write an approach that will track coverage events over time.
- The procedure will estimate how long a specific area (or the whole region) remains covered by one or more nodes.
You can break the region into grid points and occasionally check if each point is covered by at least one node. If the point is covered, increment the time covered for that point.
- Code to Calculate Coverage Reliability:
The following TCL code calculates coverage reliability by validating if the region of interest is covered at regular breaks:
# Define global variables to track coverage
set totalCoverageTime 0.0
set checkInterval 1.0 ;# Check every 1 second
set gridStep 5 ;# Grid resolution (5 meters)
# Function to check if a point (x, y) is covered by any node
proc isCovered {x y} {
global ns node_ sensingRange
set covered 0
foreach nodeID [array names node_] {
set nodeX [$node_($nodeID) set X_]
set nodeY [$node_($nodeID) set Y_]
# Calculate Euclidean distance between the node and point (x, y)
set distance [expr sqrt(($nodeX – $x) * ($nodeX – $x) + ($nodeY – $y) * ($nodeY – $y))]
# If the point is within the sensing range, mark it as covered
if {$distance <= $sensingRange} {
set covered 1
break
}
}
return $covered
}
# Function to check coverage of the entire area at a given time
proc checkCoverage {} {
global ns totalCoverageTime totalSimulationTime gridStep checkInterval
set areaCovered 0
set totalPoints 0
# Loop through the grid points and check coverage
for {set x 0} {$x <= 100} {incr x $gridStep} {
for {set y 0} {$y <= 100} {incr y $gridStep} {
incr totalPoints
if {[isCovered $x $y]} {
incr areaCovered
}
}
}
# If any part of the area is covered, increase coverage time
if {$areaCovered > 0} {
set timeCovered [expr $checkInterval * ($areaCovered.0 / $totalPoints)]
set totalCoverageTime [expr $totalCoverageTime + $timeCovered]
}
# Schedule the next coverage check
if {[$ns now] < $totalSimulationTime} {
$ns at [expr [$ns now] + $checkInterval] “checkCoverage”
}
}
# Schedule the first coverage check
$ns at 0.0 “checkCoverage”
# End the simulation after the total time has passed
$ns at $totalSimulationTime “finishSimulation”
# Function to finish simulation and print coverage reliability
proc finishSimulation {} {
global totalCoverageTime totalSimulationTime
set coverageReliability [expr ($totalCoverageTime / $totalSimulationTime) * 100]
puts “Coverage Reliability: $coverageReliability%”
exit 0
}
- Explanation of Key Elements:
- isCovered {x y}: This function confirms if the point (x, y) is inside the sensing range of any node. It returns 1 if covered and 0 otherwise.
- checkCoverage: This function iterate through grid points, verifying coverage at each point. It increments totalCoverageTime in terms of how many points are covered.
- finishSimulation: At the end of the simulation, this function calculates the overall coverage reliability as the proportion of time the region was covered.
- Running the Simulation:
- Position your nodes across the area of interest.
- Simulate the realistic conditions by modifying node mobility, failure rates and other parameters.
- Execute the simulation and observe the printed output to get the Coverage Reliability.
- Enhancing the Model:
- Node Mobility: If nodes are mobile, you can attach mobility models (like random waypoint) to mimic how node movement impacts coverage reliability.
- Node Failure: You can simulate node failure by deactivating certain nodes during the simulation and assessing how this influences coverage reliability.
- Analysis of Coverage Reliability:
- High Coverage Reliability: This represents that the area was dependably covered throughout the simulation.
- Low Coverage Reliability: This suggests that some portions of the area were left uncovered for significant periods, possibly because of node failures, mobility, or inadequate deployment.
In this manual, we have offered the step-by-step approach to calculate the coverage reliability in NS2 environment including snippet codes to track the time and formula. You can also enhance the simulation as per your preferences. If needed, we will provide another method of computation.
Figuring out Coverage Reliability in NS2 can be pretty tricky, so keep in touch with us! We’re here to help you get the best results. Just share all the parameter details, and we promise you’ll get top-notch project comparison outcomes.