To simulating Vehicle-to-Everything (V2X) communication projects using NS2 have needs to design the dynamic interactions between vehicles (V2V), vehicles and infrastructure (V2I), and potentially other entities such as pedestrians (V2P) and networks (V2N). V2X simulations usually concentrate on contexts such as mobility patterns, wireless communication protocols, message dissemination, and application-specific behaviours (such as safety messages, traffic management).
Since NS2 is not inherently intended for vehicular network simulations, with proper configuration and extensions, we can efficiently replicate V2X scenarios. Drop all your details we will give you tailored simulation assistance.
Below is a comprehensive guide to help you configure and simulate V2X communication projects using NS2.
Steps to Simulate V2X Communication Projects in NS2
- Prerequisites
1.1 Install NS2
- Download NS2: we can download the latest stable version of NS2 from the NS2 Official Website.
- Installation: Follow the installation instructions certain to your operating system (primarily Linux). Make sure that all dependencies are satisfied.
# Example for Ubuntu-based systems
sudo apt-get update
sudo apt-get install ns2
1.2 Install Network Animator (NAM)
- NAM is a envision tool for NS2. It helps visualize the network topology and message passing.
sudo apt-get install nam
1.3 Familiarize Yourself with NS2 Basics
- NS2 Language: NS2 usages TCL (Tool Command Language) for scripting simulations. Understand with TCL and NS2’s architecture is vital.
- Documentation and Tutorials: Appraisal the NS2 Tutorial and NS2 Manual for foundational knowledge.
- Understanding V2X Communication
2.1 V2X Components
- V2V (Vehicle-to-Vehicle): Communication between vehicles for collision avoidance, traffic information, etc.
- V2I (Vehicle-to-Infrastructure): Communication between vehicles and infrastructure such as traffic lights, road sensors, etc.
- V2P (Vehicle-to-Pedestrian): Communication between vehicles and pedestrians for safety.
- V2N (Vehicle-to-Network): Communication among vehicles and cellular networks for broader data exchange.
2.2 Communication Protocols
- DSRC (Dedicated Short Range Communications): According to IEEE 802.11p, intended for low-latency, high-reliability communication.
- C-V2X (Cellular V2X): Utilizes cellular networks for V2X communication.
For NS2 simulations, DSRC (IEEE 802.11p) is more straightforward to execute as NS2 has support for IEEE 802.11 protocols.
- Setting up the Simulation Environment
3.1 Define Simulation Objectives
- Scope: Regulate whether we are concentrate on V2V, V2I, or a combination.
- Metrics: Common parameters such as latency, packet delivery ratio, throughput, and message dissemination delays.
- Scenarios: Describe environment like highway traffic, urban intersections, or certain event-based simulations.
3.2 Configure Mobility Models
V2X simulations need realistic vehicle mobility models to replicate real-world movement.
3.2.1 Using NS2’s Mobility Models
NS2 has involved a simple mobility models, however for more accurate vehicular movement, consider incorporating with SUMO (Simulation of Urban MObility).
- SUMO Integration: Utilize TRM (Traffic-Related Mobility) tools to export vehicle movement to NS2.
- Manual Mobility: Alternatively, manually describe movement patterns in NS2 using the setdest command.
3.2.2 Example: Defining Mobility in NS2
# Create a simulator instance
set ns [new Simulator]
# Define trace files (optional for logging)
set tracefile [open out.tr w]
$ns trace-all $tracefile
set namfile [open out.nam w]
$ns namtrace-all $namfile
# Define number of vehicles
set num_vehicles 10
# Create vehicles (nodes)
for {set i 0} {$i < $num_vehicles} {incr i} {
set node($i) [$ns node]
}
# Define wireless channel parameters (IEEE 802.11p-like settings)
for {set i 0} {$i < $num_vehicles} {incr i} {
# Define the wireless interface (IEEE 802.11)
$node($i) set X_ 0
$node($i) set Y_ [expr $i * 10]
$node($i) set Z_ 0
}
# Define mobility patterns
# Example: Linear movement with constant velocity
for {set i 0} {$i < $num_vehicles} {incr i} {
$ns at 0.0 “$node($i) setdest [expr 100 + $i*10] [expr 100 + $i*10] 10”
}
Note: For complex mobility patterns, assimilating with SUMO or describing more intricate setdest commands is recommended.
- Configuring Wireless Communication
4.1 Setting up IEEE 802.11 Protocols
NS2 supports IEEE 802.11 protocols that can be adapted for DSRC.
4.1.1 Configure PHY and MAC Layers
- PHY Layer: Describes the physical layer features such as data rate and frequency.
- MAC Layer: Handles the medium access control, necessary for collision avoidance and handling multiple transmissions.
4.1.2 Example: Configuring 802.11 for V2X
# Define the channel type as wireless
set channel [new Channel/WirelessChannel]
$ns trace-queue $channel $tracefile
$ns node-config -adhocRouting DSDV \
-llType LL \
-macType Mac/802_11 \
-ifqType Queue/DropTail/PriQueue \
-ifqLen 50 \
-antType Antenna/OmniAntenna \
-propType Propagation/TwoRayGround \
-phyType Phy/WirelessPhy \
-channel $channel \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace ON
Explanation:
- adhocRouting DSDV: Using DSDV (Destination-Sequenced Distance-Vector) routing protocol. For V2X, consider protocols such as AODV or OLSR.
- Mac/802_11: Using IEEE 802.11 MAC layer.
- Antenna/OmniAntenna: Omnidirectional antennas are usual for vehicular communications.
- Propagation/TwoRayGround: Appropriate for open areas; adapt according to your scenario.
4.2 Setting Wireless Parameters
Adapt parameters to fit DSRC specifications.
- Frequency: 5.9 GHz for DSRC.
- Data Rate: 6, 12, 24, or 54 Mbps (based on IEEE 802.11a standards used in 802.11p).
- Channel Width: 10 MHz (specific to 802.11p).
Example:
# Set PHY layer parameters for DSRC-like communication
$ns node-config -phyType Phy/WirelessPhy \
-channel [new Channel/WirelessChannel] \
-antenna [new Antenna/OmniAntenna] \
-propType [new Propagation/TwoRayGround]
# Configure data rate and frequency
$ns node-config -phyPropagationModel “TwoRayGround” \
-phyFreq 5.9GHz \
-phyRxPower 0.0 \
-phyTxGain 1 \
-phyRxGain 1 \
-macType Mac/802_11 \
-ifqType Queue/DropTail/PriQueue \
-ifqLen 50 \
-antType Antenna/OmniAntenna \
-propType Propagation/TwoRayGround \
-phyDataRate 6Mb
Note: Adapt phyDataRate according to your requirements such as 6 Mbps for basic communication.
- Defining Applications and Traffic Patterns
5.1 Define V2X Applications
V2X applications usually include periodic message dissemination such as beacon messages, event-driven messages like collision alerts, and data exchange like traffic information.
5.1.1 Create Custom Application Agent
NS2 enable generating custom application agents by prolonging existing agents.
# Define a new agent for V2X beacon messages
Agent/V2XBeaconAgent set beaconInterval_ 1.0 ;# Beacon interval in seconds
Agent/V2XBeaconAgent set packetSize_ 200 ;# Beacon message size in bytes
5.1.2 Example: Periodic Beacon Message Generation
# Create and attach V2X Beacon Agents to each node
for {set i 0} {$i < $num_vehicles} {incr i} {
set beacon($i) [new Application/Traffic/CBR]
$beacon($i) set packetSize_ 200 ;# Beacon size in bytes
$beacon($i) set interval_ 1.0 ;# Send beacon every 1 second
$beacon($i) attach-agent $tcp($i)
}
# Schedule beacon transmissions
for {set i 0} {$i < $num_vehicles} {incr i} {
$ns at 1.0 “$beacon($i) start”
}
Note: This example utilizes CBR (Constant Bit Rate) traffic to replicate periodic beacon messages.
5.2 Define Message Types and Routing
Apply message handling logic to differentiate among message types (e.g., beacons, alerts).
5.2.1 Implementing a Simple Routing Protocol
Utilize existing routing protocols such as AODV or DSDV for message dissemination.
# Configure AODV routing protocol
$ns node-config -adhocRouting AODV
5.3 Example: Full Application Setup
# Create simulator and trace files
set ns [new Simulator]
set tracefile [open out.tr w]
$ns trace-all $tracefile
set namfile [open out.nam w]
$ns namtrace-all $namfile
# Define channel and node configurations
set channel [new Channel/WirelessChannel]
set prop [new Propagation/TwoRayGround]
set ant [new Antenna/OmniAntenna]
set phy [new Phy/WirelessPhy]
$ns node-config -adhocRouting AODV \
-llType LL \
-macType Mac/802_11 \
-ifqType Queue/DropTail/PriQueue \
-ifqLen 50 \
-antType Antenna/OmniAntenna \
-propType Propagation/TwoRayGround \
-phyType Phy/WirelessPhy \
-channel $channel \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace OFF
# Create nodes
for {set i 0} {$i < $num_vehicles} {incr i} {
set node($i) [$ns node]
}
# Define mobility for each node
for {set i 0} {$i < $num_vehicles} {incr i} {
$ns at 0.0 “$node($i) setdest [expr 100 + $i*10] [expr 100 + $i*10] 10”
}
# Create and attach V2X Beacon Agents
for {set i 0} {$i < $num_vehicles} {incr i} {
set tcp($i) [new Agent/TCP]
set sink($i) [new Agent/TCPSink]
$ns attach-agent $node($i) $tcp($i)
$ns attach-agent $node($i) $sink($i)
$ns connect $tcp($i) $sink($i)
set beacon($i) [new Application/Traffic/CBR]
$beacon($i) set packetSize_ 200
$beacon($i) set interval_ 1.0
$beacon($i) attach-agent $tcp($i)
$ns at 1.0 “$beacon($i) start”
}
# Define finish procedure
proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
exec nam out.nam &
exit 0
}
# Schedule finish
$ns at 100.0 “finish”
# Run simulation
$ns run
- Running and Visualizing the Simulation
6.1 Running the Simulation
- Save TCL script, e.g., v2x_simulation.tcl.
- execute the simulation using NS2:
ns v2x_simulation.tcl
6.2 Visualizing with NAM
- The simulation creates a .nam file (out.nam in the examples).
- If not automatically launched, open NAM manually:
nam out.nam
- NAM Features:
- Envision node movements and interactions.
- Monitor on packet transmissions and receptions.
- Evaluate network dynamics in real-time.
- Collecting and Analysing Results
7.1 Trace Files
- Trace File (out.tr): Contains detailed logs of events such as packet transmissions, receptions, and drops.
- Parse Trace Files: Utilize tools such as awk, grep, or custom scripts to extract relevant parameters.
7.2 Common Metrics
- Latency: Time taken for a message to reach its destination.
- Packet Delivery Ratio (PDR): Ratio of successfully delivered packets to the total sent.
- Throughput: Rate of successful message delivery over time.
- Jitter: Variability in packet delivery times.
- Network Overhead: Extra packets generated because of routing or control messages.
7.3 Example: Calculating Packet Delivery Ratio
We can utilize Awk to process the trace file and estimate PDR.
# Count total sent and received packets
sent=$(grep “AGT” out.tr | wc -l)
received=$(grep “RCV” out.tr | wc -l)
# Calculate PDR
pdr=$(echo “scale=2; $received / $sent * 100” | bc)
echo “Packet Delivery Ratio: $pdr%”
Note: This is a simplistic approach. For more accurate parameters, consider using specialized NS2 evaluation tools or scripts.
- Enhancing the Simulation
8.1 Incorporate Realistic Mobility with SUMO
Incorporate SUMO (Simulation of Urban MObility) for more realistic vehicle movement patterns.
- Export Trajectories: Utilize SUMO to create vehicle movement data and import into NS2.
- Synchronization: Make sure NS2 and SUMO execute in tandem for synchronized mobility and communication.
8.2 Implement Advanced V2X Protocols
NS2’s default protocols cannot fully capture V2X-specific behaviors. Consider implementing or extending:
- IEEE 1609 Standards: For handling communication services in vehicular environments.
- Dedicated V2X Applications: apply certain V2X applications such as collision avoidance, traffic light information, etc.
8.3 Integrate Security Features
Simulate security mechanisms such as encryption, authentication, and intrusion detection to learn their effect on V2X performance.
8.4 Model Network Conditions
Establish the changing network conditions to learn their impacts on V2X communications:
- Variable Traffic Load: Replicate high-density traffic scenarios.
- Channel Interference: Model interference from other wireless devices.
- Mobility Patterns: Different movement speeds and directions.
- Example: Comprehensive V2X Simulation Script
Below is a more comprehensive sample that contains mobility, application setup, and visualization.
# Initialize simulator
set ns [new Simulator]
# Open trace and NAM files
set tracefile [open v2x_sim.tr w]
$ns trace-all $tracefile
set namfile [open v2x_sim.nam w]
$ns namtrace-all $namfile
# Define channel and propagation models
set channel [new Channel/WirelessChannel]
set prop [new Propagation/TwoRayGround]
set ant [new Antenna/OmniAntenna]
set phy [new Phy/WirelessPhy]
# Configure node settings
$ns node-config -adhocRouting AODV \
-llType LL \
-macType Mac/802_11 \
-ifqType Queue/DropTail/PriQueue \
-ifqLen 50 \
-antType Antenna/OmniAntenna \
-propType Propagation/TwoRayGround \
-phyType Phy/WirelessPhy \
-channel $channel \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace OFF
# Define number of vehicles
set num_vehicles 20
# Create vehicles (nodes)
for {set i 0} {$i < $num_vehicles} {incr i} {
set node($i) [$ns node]
}
# Define initial positions and mobility
for {set i 0} {$i < $num_vehicles} {incr i} {
# Initial positions can be set here if needed
# Example: Arrange vehicles in a line
$node($i) set X_ [expr 100 + $i * 20]
$node($i) set Y_ 100
$node($i) set Z_ 0
}
# Define mobility patterns (moving east at 10 m/s)
for {set i 0} {$i < $num_vehicles} {incr i} {
$ns at 0.0 “$node($i) setdest [expr 1000 + $i * 20] 100 10”
}
# Create and attach V2X Beacon Agents
for {set i 0} {$i < $num_vehicles} {incr i} {
set tcp($i) [new Agent/TCP]
set sink($i) [new Agent/TCPSink]
$ns attach-agent $node($i) $tcp($i)
$ns attach-agent $node($i) $sink($i)
$ns connect $tcp($i) $sink($i)
set beacon($i) [new Application/Traffic/CBR]
$beacon($i) set packetSize_ 200
$beacon($i) set interval_ 1.0
$beacon($i) attach-agent $tcp($i)
# Start beacon after 2 seconds to allow network stabilization
$ns at 2.0 “$beacon($i) start”
}
# Define finish procedure
proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
exec nam v2x_sim.nam &
exit 0
}
# Schedule finish
$ns at 100.0 “finish”
# Run simulation
$ns run
- Tips and Best Practices
10.1 Validate Your Simulation
- Small-Scale Tests: initiate with a small number of nodes to validate behaviour.
- Compare with Real-World Data: check simulation outcomes against empirical data if available.
10.2 Modularize Your Scripts
- Reusable Components: Generate reusable TCL scripts for common tasks such as node creation, mobility setup, and application configuration.
- Comments and Documentation: Clearly comment the scripts for easier maintenance and considerate.
10.3 Optimize Simulation Parameters
- Scalability: Adapt parameters to make sure simulations execute efficiently, specific with a large number of nodes.
- Accuracy vs. Performance: Balance the level of detail with simulation performance according to your objectives.
10.4 Explore Extensions and Alternative Simulators
Since NS2 can be modified for V2X simulations, consider discover other simulators intended for vehicular networks for more advanced characteristics:
- NS3: The successor to NS2 with better support for modern networking protocols and extensions.
- Veins: Incorporate SUMO with OMNeT++ for detailed vehicular network simulations.
- MATLAB-based Simulations: For custom V2X design with certain analytical necessities.
From the entire manual, we had understood and gain knowledge on the concepts of Vehicle-to-Everything using ns2 tool including examples and their explanations which helps to complete the simulation process. Additional specific details regarding the Vehicle-to-Everything will also be provided.
