How to Implement MIMO in ns2

To implement the MIMO (Multiple Input Multiple Output) in ns2 (Network Simulator 2), we can’t directly execute this due to ns2 lacks the support for advanced wireless features like MIMO. Yet, you can fairly precise the MIMO actions by tailoring the wireless channel properties and using several wireless interfaces on nodes to imitate some perspectives of MIMO. It will be a basic simulation and won’t fully cover the extremes of MIMO systems. Get best simulation result from us, by sharing your project details with us.

Here in the below, we offered the procedure for the implementation of MIMO using ns2:

Step-by-Step Implementation:

Step 1: Understanding the Limitations

Ns2 was generated before MIMO technology became well-known, so it does not have the in-built support for replicating MIMO systems that has several antennas at both the transmitter and receiver to enhance communication performance. To simulate MIMO in ns2, we may need to follow the below:

  1. Approximate MIMO behavior by maximizing the data rate and decreasing the error rate on the wireless links.
  2. Simulate multiple channels to denote the numerous spatial streams that MIMO would use.
  3. Use multiple wireless interfaces on the nodes to imitate the impact of multiple antennas.

Step 2: Create the Tcl Script

Below is a shortened Tcl script to simulate MIMO-like actions by setting up several wireless interfaces and optimizing link characteristics to recreate the enhanced performance of MIMO.

Example Tcl Script for Simulating MIMO-like Behavior

# Create a simulator object

set ns [new Simulator]

# Define the topography object

set topo [new Topography]

$topo load_flatgrid 1000 1000

# Create the General Operations Director (GOD) for wireless simulations

create-god 2  # Number of nodes in the network

# Configure the first wireless interface (representing one MIMO stream)

$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 \

-channelType Channel/WirelessChannel \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace ON

# Create nodes

set n0 [$ns node]

set n1 [$ns node]

# Position nodes

$n0 set X_ 100.0

$n0 set Y_ 200.0

$n0 set Z_ 0.0

$n1 set X_ 300.0

$n1 set Y_ 400.0

$n1 set Z_ 0.0

# Add another wireless interface (representing another MIMO stream)

set phy1 [new Phy/WirelessPhy]

set ant1 [new Antenna/OmniAntenna]

$phy1 set Antenna_ $ant1

$phy1 set channel_ [$ns node-channel $n0]

set mac1 [new Mac/802_11]

$mac1 set phy_ $phy1

$mac1 set ifqType_ Queue/DropTail/PriQueue

$mac1 set ifqLen_ 50

$mac1 set llType_ LL

$n0 add-interface $mac1

# Repeat for the second node

set phy2 [new Phy/WirelessPhy]

set ant2 [new Antenna/OmniAntenna]

$phy2 set Antenna_ $ant2

$phy2 set channel_ [$ns node-channel $n1]

set mac2 [new Mac/802_11]

$mac2 set phy_ $phy2

$mac2 set ifqType_ Queue/DropTail/PriQueue

$mac2 set ifqLen_ 50

$mac2 set llType_ LL

$n1 add-interface $mac2

# Configure duplex link to represent improved MIMO performance

$ns duplex-link $n0 $n1 200Mb 1ms DropTail  # Increase data rate and reduce delay

# Define TCP traffic between nodes to simulate data transmission

set tcp [new Agent/TCP]

$ns attach-agent $n0 $tcp

set sink [new Agent/TCPSink]

$ns attach-agent $n1 $sink

$ns connect $tcp $sink

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ftp start

# Schedule the end of the simulation

$ns at 10.0 “finish”

# Run the simulation

$ns run

Step 3: Run the Tcl Script

Save the script with a .tcl extension, for instance, mimo_simulation.tcl. Then execute the script using the below command in your terminal:

ns mimo_simulation.tcl

Step 4: Visualize the Simulation

To visualize the network and the traffic, open the created NAM file using:

nam mimo_out.nam

It will show the nodes, the links amongst them and the simulated traffic.

Script Explanation

  • Multiple Wireless Interfaces: It attach a second wireless interface to every node to replicate the usage of multiple antennas in MIMO system. It is very simple fairly precise and lacks to recreate the original spatial diversity and multiplexing gains of MIMO.
  • Improved Link Characteristics: The script maximizes the data rate (200Mb) and decreases the delay (1ms) on the duplex link to indicate the optimized performance that MIMO could deliver.
  • TCP Traffic: TCP traffic is stated amongst the two nodes to replicate data transmission, showcasing the enhanced throughput because of the simulated MIMO actions.

Limitations

  • Simplification: This process does not truly simulate MIMO however fairly precise it by enhancing link characteristics and using multiple interfaces.
  • Lack of Advanced MIMO Features: Mechanisms like spatial diversity, beamforming, or the actual parallel data streams are not modeled.
  • Not a True MIMO Simulation: For a realistic simulation of MIMO systems, you may need to utilize more advanced simulators like ns3, which has better support for modern wireless communication technologies.

In this procedure, we entirely offered the guide to help you get started with a basic MIMO simulation in ns2 by approximating the behavior and recreate multiple channel and then using several wireless interfaces. Also, it has some restrictions to implement it however you can fairly precise its capabilities.