NS3 Vertical Handover

Vertical handover is the process of migrating/moving the users from the current networks to the target networks. This concept addresses the mobility issue. Nowadays, vertical handover/handoff (VHO) has reached a high level of popularity in 4G wireless networking technologies. 

In specific, the VHO among UMTS (WCDMA) and WLAN have earned extensive attraction among active research scholars. The reasons behind this high demand are better mobility, low cost (WLAN), high coverage (UMTS), and greater bandwidth UMTS (WCDMA). For instance: On using media-independent HO (802.21), one can accomplish the Wi-Max-based VHO between wireless and wired access technologies. 

Here, we have given you the basic requirements of the WiMAX-based VHO process for execution.

• Mobility Area
  • Wide-ranging mobility
• Incidences
  • Free movement of mobile nodes over different access technologies
• Network selection technologies 
  • WLAN-Wi-Max and UMTS-WLAN
• IP Address
  • When the mobile node’s network interface changes then the IP address also changes

One of the biggest challenges of the cellular network is achieving efficient HO control due to the small cells which allow usage of high capacity and coverage in geo-based locations. Similarly, it has other challenges that gain large attraction from the researcher’s perspective. And, some of them are given below. Our technical professionals are expertise in handling not only these issues but also other upcoming issues. So, we support you through optimal research solutions to solve any kind of complex problems in NS3 vertical handover.

Research Issues of Vertical Handover

• New Connectivity
  • Connection Routing
  • Resource Distribution
• Control of Content Streaming
  • Multicasting
  • Sequencing / Buffering
• Instigation
  • Network States
  • User Mobility

Basically, there are many ways to develop using ns3 vertical handover model like analytical modeling, simulation, physical testbeds, and real-world implementation. Currently, everybody prefers the simulation approach which offers a sophisticated environment to create realistic network virtualization. For VHO simulation, the network simulator has furnished with below specified important characteristics. 

• Scalability
• Increased Mobility Characteristics
• User-friendliness 

In particular, we prefer Network simulator NS3 vertical handover projects. Since, it is well-suited for designing, developing, testing, and simulating the vertical handover by doing small modifications in code. Also, there are no independent tools for vertical handover but NS3 provides maximum opportunities to take efficient handover decisions. Most importantly, NS3 is the extended version of the NS2 simulator which overcomes its major issues. And, some of the improved aspects of the NS3 are given below, 

• Correction of Split Language Entities
• Integration of Models 
• Inappropriate Management of Memory 
• Interoperability 

Primarily, there are two ways to implement NS3 Vertical Handover. On the other hand, it can be applied as a manual process. On the other hand, it can be applied as an automated process. Most probably, many of the scholars choose an automated process for their vertical handover project. Our experts give the best guidance in both approaches to fulfill your project requirements effectively. 

Vertical handover using NS3

• Automatically
  • Depends on handover scheme and UE measurements, eNodeB RRC entity will perform initiation
• Explicitly 
  • Schedule the LteEnbRrc::SendHandoverRequest; method execution for initiation

Next, we can see the simulation procedure for the vertical handover process in the NS3 tool. Here, we have classified the whole process based on key operations of handover. These steps are general for developing a basic VHO model and further, it may vary based on the individual application needs. We support you in every aspect of VHO processes like VHO technique selection, optimal network selection, handover decision-making, and handover execution and performance evaluation. 

Vertical Handover Simulation

• Femto cell and Mobile UEs
  • At first, create the femto cell and allocate the mobile user equipment
  • Verify and evaluate the cells for designing femto cell
• Macro-cells
  • Create macro-cells and allocate the femto cells within macro-cells
  • Assign suitable radio interference model to simulate the real-time radio network
  • Assign UEs which roaming over femto cells in various configurations
• EPC connection
  • Link the radio network to the EPC with internet access
  • EPC – Internet, SGW and MME
• Traffic Modeling
  • Managing various traffics in the model
  • Utilize busty traffic, video TCP traffic and CBR traffic for management
• Statistic Wire
  • To collect and inspect results, create the statistic wire in various points
• Scenario Creation and Simulation
  • Based on base configuration, create various kinds of scenarios
  • At last, simulate the created scenarios and evaluate the performance

Further, our developers have given you the list of fundamental header files used for vertical handover development in the NS3 tool. These header files comprise a huge collection of libraries and classes to meet the functional requirements of the handover process. Further, there are more modules designed to support specific networks and access technologies. Our developers are adept to handle and incorporate the necessary header files and libraries based on handpicked network technologies for handover. 

NS3 Modules (Header Files) for Vertical Handover 

• #include
  • <ns3/test.h>
  • “ns3/lte-module.h”
  • “ns3/core-module.h”
  • “ns3/network-module.h”
  • “ns3/applications-module.h”
  • “ns3/internet-module.h”
  • “ns3/point-to-point-module.h”
  • “ns3/mobility-module.h”
  • “ns3/config-store-module.h”

From the above list of header files, we have selected “NS3/LTE-module.h” as an example. Now, we can see in what way the LTE module works in vertical handover simulation. Here, we have highlighted the essential properties of the 3GPP LTE which support vertical handover. Similarly, we support other modules intending to achieve optimized handover.

For instance, how LTE module supports for Vertical Handover

• Network-controlled
  • Handover decision, initiation, supervision and simulation are under the control of network
• UE-assisted
  • For VHO process, the input parameters are collected from the user equipment (UE)
  • Then, the collected parameters are given to the network in measurements format
  • This overall process can be managed through UE RRC Measurements Model

As a matter of fact, the handover algorithm takes effective automated decisions for efficient handover in source eNodeB. It enables communication of eNodeB RRC instances through the HO-SAP interface. Further, we have given you the 2 significant elements that improve the behavior of the HVA. And, our developers are smart to tackle the complexity of HOA through advanced technologies. Two attributes can be set to tune the algorithm behavior:

• NeighbourCellOffset
  • Offset is intended to attain high signal quality once the HO is completed
  • Neighbor cell act as a target cell for HO
  • In this, RSRQ value should be greater than RSRQ of serving cell through its offset
• ServingCellThreshold
  • Set threshold value for Event A2
  • In this, RSRQ value of user equipment should be lower than the threshold for HO

Generally, the above-specified attributes are represented in the RSRQ value. This value ranges from 0 to 34 (positive integer) where the lowest RSRQ value is 0. Further, our developers have also given the procedure to calculate the RSRQ value. It also includes the network selection procedure based on the RSRQ value. Let’s have a look over the below steps, 

• Step 1 – UE send measurement reports to eNodeB through Event A4 and A2
  • User Parameters
    • User preferences (QoS, cost and security)
    • Terminal features (battery, velocity and reinforced RATs)
• Step 2 – If RSRQ of serving cell is less than the threshold then it finds neighbor cell with best RSRQ else again go to step 1
  • Network Parameters (best Network selection)
    • Network state (load, bandwidth, security, link quality)
    • Operator preferences (resource and revenue)
    • Services (QoS and QoE)
    • Available RATs (CPICH Ec/NO and RSS)
• Step 3 – If the value (neighbor RSRQ – serving cell RSRQ) is greater than or equal to neighborcell Offset then initiate the HOA to best neighbor else repeat from step 1

In addition, we have also included the primitives required for the X2-based handover function for your awareness. 

• UE Context Release`
• Handover Request
• SN Status transfer
• Handover Request ACK
• Handover Preparation Failure

The above-specified primitives have a key player role in the current RRC model for designing, developing, and executing HO algorithms. Also, it is more useful in customizing code not only for communicating with the RRC model but also for adjusting the RRC state machine. Here, we have given you the major functions used for the execution of the handover algorithm in implementing ns3 vertical handover research projects. Also, it includes the procedure of handover in 3 different phases starting from user measurement configuration to handover algorithm trigger.

Steps for Vertical Handover Simulation using NS3

• AddUeMeasReportConfigForHandover
  • HOA transmit report configuration to eNodeB RRC entity for requesting measurement reports
  • Here, the configuration takes place will available user equipment
• ReportUeMeas
  • User equipment transmit the report to the eNodeB through their configured measurements
  • Then, the eNodeB RRC entity forward the measurement reports to the HOA using ReportUeMeas
• TriggerHandover
  • Inspect the measurements reports for decision-making
  • Declare the handover decision by HOA for informing eNodeB RRC entity
  • Next, follow the HO procedure for execution

Before simulating the vertical handover scenario, we need to follow the below steps in NS3:

Overview of NS3 Simulation System

• Setup for Simulation
  • Describe the simulation scenarios with time and parameters  
• Code Simulation
  • Code the simulation process suitable for described scenarios
• Outline of Metrics and Results Estimate
  • Adjust the metrics of configuration and performance to assess the experimental results

Next, follow the below approaches to examine the behavior of the modeled system:

• Physical Measurements in Real-world
  • It is a real-time implementation which requires extreme time, cost and resources
• Analytical Modeling
  • It is tedious for complicated models to analyze the functionalities of models
• Computer Network Simulations / Virtualization
  • It is widely used practical method to perform both qualitative and quantitative analysis for traffic and computer networks

Generally, the parameters are used to evaluate the performance of the system. In fact, these parameters are not only used for performance evaluation but also for performance improvement in the designing phase. Based on the parameter value selection, we can enhance the performance of the handover process. This is achieved by following the below procedure using NS3simulator. 

How to optimize the vertical handover performance using NS3?

• Test and evaluate the generated models based on values of parameters to enhance the system optimization
• Identify the suitable network parameters to enhance the network optimization (reliable and fast)

Next, we can see the current emerging technologies of vertical handover. Our research and development teams are currently working on many types of research in the following technologies to support you in every aspect. 

Key Technologies in Vertical Handover

• Edge Networks
• LTE Networks
• Internet of Vehicles (IoV)
• Software Defined Networks (SDN)
• Mobile Ad Hoc Networks (MANET Simulator)
• Vehicular Ad Hoc Networks (VANET)

For any technology, we need to assess the performance of the system in vertical handover simulation. So, here we have given you the list of parameters used for the configuration phase. Further, we also support you in enhancing the efficiency of the system based on your project requirements.

Simulation Parameters for Vertical Handover 

• Count of Overall Completed Handovers
• Mobility Metrics     // incase of IoV, or vehicular systems
  • obuS (static value or configuration wait time (in m/s))
  • obuD (static value or configuration wait time (in m))
  • rsuD / APs (static value or configuration wait time (in ms))
• Network Metrics
  • ProbeDelay (static value or configuration wait time (in ms))
  • ChannelTime (static value or configuration wait time (in ms))
  • ScanType (Passive, Active and Both)
  • MaxChannelTime (static value or configuration wait time (in ms))
  • BeaconInterval (static value or configuration wait time (in ms))
  • MinChannelTime (static value or configuration wait time (in ms))
• Other Metrics
  • Route trace file for present execution (string)
  • Number of execution iterations for each simulation (positive integer)
  • Signal Interference Noise Ratio (SINR) (dB)

Example for NS3 based Vertical handover

In cellular networks (4G and 5G beyond), the best algorithm for selecting a network is Multiple Attribute Decision Making (MADM). Actually, it is composed of several techniques. For illustration purposes, now we have selected VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) technique. It is one of the best techniques in MADM for network selection. For your information, now we can see the development of NS3 vertical handover with their simulation parameters. 

Simulate the real-time NS3 vertical handover

• At first, filter the QoS parameters
• Meanwhile, collect application needs and perform pairwise comparison (streaming, interactive, streaming and conversational)
• Then, compute the AHP weights by QoS parameters and pairwise comparison
• Implement VIKOR technique
• Decide on network selection
• At last, execute the handover process

NS3 Simulation Parameters

• Sum of Nodes
  • 100
• Simulation Duration
  • 650s
• Available Networks
  • Wi-Max and WLAN
• Quality of Services (QoS)
  • Jitter
  • Throughput
  • Bit Error Rate
  • End-to-end Latency
• Range of WLAN (m)
  • 150
• Area Size (m²)
  • 500*500
• Mobility Models
  • Constant Velocity
• Range of Wi-Max (m)
  • 500
• Traffic of Application
  • Streaming (Video)
  • Background (Emailing)
  • Conversational (Voice)
  • Interactive (Web traffic)

On the whole, we support you in every aspect of NS3 vertical handover development and simulation. Further, we also provide you up-to-date research topics to match your research expectation. And also, we encourage our handhold scholars to bring their ideas to support their requirements. So, if you are looking for the best guidance for your research journey then approach us. We assure you that we fulfil your needs with a high-quality experimental outcome.

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