How to Implement Network Slicing HetNets in NS2

To implement the Network Slicing in HetNets (Heterogeneous Networks) in NS2, we have to develop a several virtualized network slices over a shared physical infrastructure. Every slice have various aspects (such as bandwidth, latency or priority) and can serve various kinds of services including enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), or ultra-reliable low-latency communication (URLLC). It is very important for 5G and beyond in which different services require unique levels of performance. In the below, we provided the implementation steps of Network Slicing HetNets using ns2:

Overview of Network Slicing in HetNets

HetNet (Heterogeneous Networks) have a different kinds of networks like macrocells, small cells and Wi-Fi coexist. We can distribute resources differently over these networks by enforcing the network slicing, we have to certainly build multiple “virtual” networks, each enhanced for a particular type of service.

Key Elements:

  1. HetNet: Consisting of macrocells, small cells, and Wi-Fi networks.
  2. Network Slices: Logical partitions of the network infrastructure, each serving certain traffic.
  3. Traffic Types: Various slices will manage different variants of traffic like high bandwidth for eMBB or low-latency communication for URLLC.

Steps to Implement Network Slicing in HetNets in NS2

  1. Set Up the NS2 Environment

Make sure to install the ns2 and check whether it is properly configured on your system. If not, you can install NS2 using the below command:

wget https://sourceforge.net/projects/nsnam/files/latest/download -O ns-allinone-2.35.tar.gz

tar -xzvf ns-allinone-2.35.tar.gz

cd ns-allinone-2.35

./install

  1. Design HetNet Topology

The HetNet will consist of numerous types of networks, including:

  • Macrocells: Large coverage, high-power base stations.
  • Small Cells: Low-power base stations offering maximized capacity in high-density areas.
  • Wi-Fi Access Points: Used to offload traffic or offer extra coverage.

2.1 Create HetNet Nodes

Generate nodes for macrocells, small cells, Wi-Fi access points, and user devices that will be distributed to multiple slices.

Example OTcl Script to Create HetNet Nodes:

# Create a simulator object

set ns [new Simulator]

# Open a NAM trace file for network animation

set nf [open out.nam w]

$ns namtrace-all $nf

# Macrocell Base Station

set macrocell [$ns node]

# Small Cells

set smallcell1 [$ns node]

set smallcell2 [$ns node]

# Wi-Fi Access Points

set wifi1 [$ns node]

set wifi2 [$ns node]

# User Devices

set user1 [$ns node]

set user2 [$ns node]

set user3 [$ns node]

set user4 [$ns node]

# Define Backhaul Connections

# Macrocell to core network

set core [$ns node]

$ns duplex-link $macrocell $core 1Gb 5ms DropTail

# Small cells to core network

$ns duplex-link $smallcell1 $core 1Gb 2ms DropTail

$ns duplex-link $smallcell2 $core 1Gb 2ms DropTail

# Wi-Fi to core network

$ns duplex-link $wifi1 $core 100Mb 10ms DropTail

$ns duplex-link $wifi2 $core 100Mb 10ms DropTail

# Users connected to different access points (dynamic allocation will follow)

$ns duplex-link $user1 $macrocell 100Mb 20ms DropTail

$ns duplex-link $user2 $smallcell1 100Mb 10ms DropTail

$ns duplex-link $user3 $smallcell2 100Mb 10ms DropTail

$ns duplex-link $user4 $wifi1 50Mb 15ms DropTail

  1. Define Network Slices

Each slice will have various aspects in terms of service demands:

  • Slice 1 (eMBB): High bandwidth for streaming or enhanced mobile broadband.
  • Slice 2 (URLLC): Ultra-low latency communication for applications like autonomous driving or IoT.
  • Slice 3 (mMTC): Massive machine-type communication for IoT devices.

Modify the bandwidth, delay and traffic priority amongst user devices and network nodes to discriminate slices.

3.1 Create Slice Parameters

# Create network slices by defining different link capacities and delays

# Slice 1 (eMBB): High Bandwidth

$ns duplex-link $user1 $macrocell 500Mb 5ms DropTail

# Slice 2 (URLLC): Ultra-low latency

$ns duplex-link $user2 $smallcell1 100Mb 1ms DropTail

# Slice 3 (mMTC): Massive communication with lower priority and bandwidth

$ns duplex-link $user3 $smallcell2 50Mb 50ms DropTail

In this setup:

  • eMBB slice uses high-bandwidth, low-delay links.
  • URLLC slice uses low-latency, high-priority links.
  • mMTC slice uses lower-priority, low-bandwidth links.
  1. Simulate Traffic for Each Slice

Use TCP or UDP agents to design various traffic patterns for each slice. For instance:

  • Slice 1 (eMBB) will produce high-bandwidth TCP traffic.
  • Slice 2 (URLLC) will have low-latency UDP traffic.
  • Slice 3 (mMTC) will manage low-priority traffic.

4.1 Generate Traffic for Slices

Example OTcl Script for Traffic Generation:

# Slice 1 (eMBB) – TCP traffic for user1

set tcp1 [new Agent/TCP]

$ns attach-agent $user1 $tcp1

set sink1 [new Agent/TCPSink]

$ns attach-agent $macrocell $sink1

$ns connect $tcp1 $sink1

# Create CBR traffic for Slice 1

set cbr1 [new Application/Traffic/CBR]

$cbr1 attach-agent $tcp1

$cbr1 set packetSize_ 1000   ;# Packet size of 1000 bytes

$cbr1 set rate_ 100Mb        ;# Data rate of 100 Mbps

# Start eMBB traffic at 1.0 seconds

$ns at 1.0 “$cbr1 start”

# Slice 2 (URLLC) – UDP low-latency traffic for user2

set udp2 [new Agent/UDP]

$ns attach-agent $user2 $udp2

set sink2 [new Agent/Null]

$ns attach-agent $smallcell1 $sink2

$ns connect $udp2 $sink2

# Create CBR traffic for Slice 2

set cbr2 [new Application/Traffic/CBR]

$cbr2 attach-agent $udp2

$cbr2 set packetSize_ 800    ;# 800-byte packets

$cbr2 set rate_ 50Mb         ;# 50 Mbps rate

# Start URLLC traffic at 2.0 seconds

$ns at 2.0 “$cbr2 start”

# Slice 3 (mMTC) – Lower-priority UDP traffic for user3

set udp3 [new Agent/UDP]

$ns attach-agent $user3 $udp3

set sink3 [new Agent/Null]

$ns attach-agent $smallcell2 $sink3

$ns connect $udp3 $sink3

# Create CBR traffic for Slice 3

set cbr3 [new Application/Traffic/CBR]

$cbr3 attach-agent $udp3

$cbr3 set packetSize_ 500    ;# Smaller packets for IoT devices

$cbr3 set rate_ 10Mb         ;# Low rate for mMTC

# Start mMTC traffic at 3.0 seconds

$ns at 3.0 “$cbr3 start”

This traffic generation replicates different kinds of data being delivered over various slices of HetNet.

  1. Dynamic User Allocation to Slices

Users can be dynamically allocated to different slices depends on factors like signal strength, network load, or QoS demands. Simulate this dynamic activity by altering the traffic patterns or move users amongst slices during the simulation.

5.1 Dynamic Slice Switching

For example, a user initially linked to Slice 3 (mMTC) can be swapped to Slice 2 (URLLC) according to its latency requirements.

# After 5 seconds, switch user3 from mMTC slice to URLLC slice due to latency requirement

$ns at 5.0 “$ns duplex-link-delete $user3 $smallcell2”

$ns at 5.0 “$ns duplex-link $user3 $smallcell1 100Mb 1ms DropTail”

  1. Enable Trace Files and Visualization

Enable trace files to observe the performance of the HetNet with slicing and visualize the simulation by using NAM (Network Animator).

6.1 Enable Trace Files:

# Create a trace file to record simulation data

set tracefile [open “out.tr” w]

$ns trace-all $tracefile

6.2 Run and Visualize the Simulation:

After running the simulation, you can visualize it in NAM:

ns your_script.tcl

nam out.nam

  1. Performance Analysis of HetNet Slices

You can assess the performance of each slice by:

  • Throughput: Verify the data rate for each slice.
  • Latency: Computing end-to-end delay for each traffic type.
  • Packet Loss: Analyzing the packet loss rate in various slices.

This can be accomplished by parsing the trace file with tools like AWK or Python scripts.

In this step-by-step approach, we have delivered the details on how to install the simulation tool and how to define HetNet topology to implement the Network Slicing in Heterogenous Network using NS2 tool. Also, we provided additional instructions like how to analyze the simulation and so on.

Our expertise lies in enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable low-latency communication (URLLC). Contact us for expert guidance on implementing Network Slicing in HetNets using NS2.