How to Implement Fog RAN in ns2

To implement the Fog Radio Access Network (F-RAN) within ns2 (Network Simulator 2) that has a challenging because of the limitations of ns2, that was not created for modern network models such as Fog computing or 5G. But, we can estimated the idea of F-RAN by mimicking a network architecture in which contains fog nodes, remote radio heads (RRHs), and centralized baseband units (BBUs). This fog nodes performs as intermediate processing units that can manage tasks nearer to the user devices, decreasing latency and offloading some of the workload from the central BBU.

Step-by-Step Implementations:

Conceptual Overview

In a Fog RAN architecture:

  1. Fog Nodes: It has nodes are set up nearer to the end users to offer local processing, storage, and networking capabilities.
  2. Remote Radio Heads (RRHs): These are the dispersed antennas that manage the radio frequency (RF) communication including the mobile users.
  3. Baseband Unit (BBU) Pool: A centralized unit in which difficult baseband processing is executed.
  4. Fronthaul Network: The communication links among the RRHs, Fog nodes, and the BBU pool.

Step 1: Conceptualize the Fog RAN Simulation

In this instance, we can emulate a Fog RAN architecture with the below components:

  • RRHs: Denoted as nodes that connect to the user devices.
  • Fog Nodes: Performs as middle nodes among the RRHs and the BBU pool.
  • BBU Pool: Signifies the centralized baseband processing unit.
  • Fronthaul and Fog Links: Mimic communication links among the RRHs, Fog nodes, and the BBU pool.

Step 2: Create the Tcl Script

The following is an example Tcl script that emulates a basic Fog RAN scenario in ns2.

Example Tcl Script for Simulating Fog RAN in ns2

# Create a simulator object

set ns [new Simulator]

# Define the topography object

set topo [new Topography]

$topo load_flatgrid 2000 2000  # 2km x 2km area

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

create-god 12  # Number of nodes (6 RRHs, 3 Fog nodes, 1 BBU Pool, 2 User devices)

# Configure the nodes for Fog RAN communication

$ns node-config -llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 100 \

-antType Antenna/OmniAntenna \

-propType Propagation/TwoRayGround \

-phyType Phy/WirelessPhy \

-channelType Channel/WirelessChannel \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace OFF

# Open trace and NAM files for recording the simulation

set tracefile [open fogran_out.tr w]

$ns trace-all $tracefile

set namfile [open fogran_out.nam w]

$ns namtrace-all-wireless $namfile 2000 2000

# Define a finish procedure to close files and end the simulation

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam fogran_out.nam &

exit 0

}

# Create the BBU Pool node (centralized baseband processing)

set bbu_pool [$ns node]

# Create Fog nodes (intermediate processing)

set fog1 [$ns node]

set fog2 [$ns node]

set fog3 [$ns node]

# Create RRH nodes (remote radio heads)

set rrh1 [$ns node]

set rrh2 [$ns node]

set rrh3 [$ns node]

set rrh4 [$ns node]

set rrh5 [$ns node]

set rrh6 [$ns node]

# Create user device nodes

set user1 [$ns node]

set user2 [$ns node]

# Set positions for BBU Pool, Fog nodes, RRHs, and user devices

$bbu_pool set X_ 1000.0

$bbu_pool set Y_ 1000.0

$bbu_pool set Z_ 0.0

$fog1 set X_ 500.0

$fog1 set Y_ 1000.0

$fog1 set Z_ 0.0

$fog2 set X_ 1000.0

$fog2 set Y_ 1500.0

$fog2 set Z_ 0.0

$fog3 set X_ 1500.0

$fog3 set Y_ 1000.0

$fog3 set Z_ 0.0

$rrh1 set X_ 300.0

$rrh1 set Y_ 800.0

$rrh1 set Z_ 0.0

$rrh2 set X_ 700.0

$rrh2 set Y_ 1200.0

$rrh2 set Z_ 0.0

$rrh3 set X_ 1300.0

$rrh3 set Y_ 1200.0

$rrh3 set Z_ 0.0

$rrh4 set X_ 1700.0

$rrh4 set Y_ 800.0

$rrh4 set Z_ 0.0

$rrh5 set X_ 500.0

$rrh5 set Y_ 500.0

$rrh5 set Z_ 0.0

$rrh6 set X_ 1500.0

$rrh6 set Y_ 500.0

$rrh6 set Z_ 0.0

$user1 set X_ 600.0

$user1 set Y_ 1100.0

$user1 set Z_ 0.0

$user2 set X_ 1400.0

$user2 set Y_ 900.0

$user2 set Z_ 0.0

# Define fronthaul links between RRHs and Fog nodes

$ns duplex-link $rrh1 $fog1 1Gb 10ms DropTail

$ns duplex-link $rrh2 $fog1 1Gb 10ms DropTail

$ns duplex-link $rrh3 $fog2 1Gb 10ms DropTail

$ns duplex-link $rrh4 $fog3 1Gb 10ms DropTail

$ns duplex-link $rrh5 $fog1 1Gb 10ms DropTail

$ns duplex-link $rrh6 $fog3 1Gb 10ms DropTail

# Define links between Fog nodes and BBU Pool

$ns duplex-link $fog1 $bbu_pool 10Gb 20ms DropTail

$ns duplex-link $fog2 $bbu_pool 10Gb 20ms DropTail

$ns duplex-link $fog3 $bbu_pool 10Gb 20ms DropTail

# Define communication links between users and RRHs (wireless links)

$ns duplex-link $user1 $rrh2 1Gb 5ms DropTail

$ns duplex-link $user2 $rrh4 1Gb 5ms DropTail

# Define traffic between the users and the BBU pool via Fog nodes and RRHs

set tcp1 [new Agent/TCP]

$ns attach-agent $user1 $tcp1

set sink1 [new Agent/TCPSink]

$ns attach-agent $bbu_pool $sink1

$ns connect $tcp1 $sink1

set ftp1 [new Application/FTP]

$ftp1 attach-agent $tcp1

$ftp1 start

set tcp2 [new Agent/TCP]

$ns attach-agent $user2 $tcp2

set sink2 [new Agent/TCPSink]

$ns attach-agent $bbu_pool $sink2

$ns connect $tcp2 $sink2

set ftp2 [new Application/FTP]

$ftp2 attach-agent $tcp2

$ftp2 start

# Schedule the end of the simulation

$ns at 20.0 “finish”

# Run the simulation

$ns run

Step 3: Run the Tcl Script

We may save the script with a .tcl extension, for instance, fogran_simulation.tcl and then we run the script using the below command in the terminal:

ns fogran_simulation.tcl

Step 4: Visualize the Simulation

We can visualize the emulation, open the created NAM file using:

nam fogran_out.nam

Script Explanation

  • BBU Pool Node: The bbu_pool node is signifies the centralized baseband processing unit.
  • Fog Nodes: The fog nodes like fog1, fog2, and fog3 are denote the middle fog nodes that process data nearer to the users, decreasing latency and offloading some tasks from the BBU pool.
  • RRH Nodes: The rrh1 to rrh6 nodes are signifies the remote radio heads in which to communicate with user devices and forward data to the fog nodes.
  • User Devices: The user1 and user2 nodes are denotes the mobile users connected to the RRHs.
  • Fronthaul Links: The links among the RRHs, fog nodes, and the BBU pool emulate the fronthaul network that connects these components.

Customization

  • Multiple Users: Append more user nodes to mimic a bigger number of users connected to various RRHs.
  • Advanced Traffic Patterns: Testing with various traffic patterns like VoIP, video streaming to mimic several services and QoS requirements in the Fog RAN architecture.
  • Mobility Models: To execute the mobility models to emulate user mobility among various RRHs and fog nodes.
  • Fronthaul Network Variations: Change the fronthaul network parameters like bandwidth, latency to learn the effect on overall network performance.

Limitations

  • Simplified Approximation: This emulation offers a basic model of Fog RAN and it does not encapsulate the comprehensive complexity of advanced Fog RAN characteristic, like dynamic resource allocation, load balancing, or distributed fog computing.
  • No Physical Layer Simulation: This script does not mimic the physical layer features particular to Fog RAN, like RF signal processing or advanced wireless methods such as beamforming.
  • Limited Fog RAN-Specific Features: The tool ns2 is not created for Fog RAN networks, thus the simulation is limited to simple functionality and high-level abstractions.

In this above demonstration shows various stages for the Fog RAN that were executed and simulated using the ns2 simulation tool. If you need more information regarding this topic we will provide it.

Fog RAN project topics with implementation results are supported by the developers at ns2projects.com, who assist you in enhancing project performance. We focus on user devices, reducing latency and offloading in the Fog Radio Access Network (F-RAN) using ns2.