📶 Visualizing the transmission between users and base stations!

Play with it! https://chonyy.github.io/handoff-visualizer/

Handoff is the transition for any given user of signal transmission from one base station to a geographically adjacent base station as the user moves around. In this project, we visualize the process of handoff by generating cars moving around the blocks and connecting them to different base stations based on different policies.

This project is to visualize handoff and make the concept of handoff in wireless network easy to understand. Different policies are implemented to perform the handoff in different situations. The goal is to make the users try out all the different policies, understand the differences, and find out the most efficient policy.

If your are interested in this visualiztion, please also check out the handoff-simulator. We want people to understand handoff in this visualizer project, and we value the data in that handoff-simulator.

Simulation Structure

Each node is a 20 * 20 (m^2) square. A block is composed of 24 nodes, whick makes the block size 120 * 80 (m^2). Cars are assummed to be moving on an extremely thin line path between blocks, the path doesn't take up any space. The velocity of the car is 20m/s. In our simulation, we iterate once in a second. The cars move one node, and all the data are calculated and updated every second.

• Velocity = 72km/hr = 20m/s
• Probability of cars entrance follows Poisson distribution
• ⋋ = 1 cars/ min [ P(t) = ⋋"e" ^(−"⋋" ) (t is in sec) ]
• Probability of cars turning based on predefined value listed below
• Received Power Calculation explained below

Car Entrance Distribution

The probability of the entrance follows Poisson distribution and

In our simultation

• ⋋ = 0.0167 cars/ sec
• k = 1

Received Power

The received power is calculated by the formula below. Read ScienceDirect to dig deeper.

• Base station transmission Pt(mW) = -50 dBm
• Base = 1mW
• 10log(Pt / Base) = dBm
• First-meter path loss = 10 dBm
• P0 = -50 dBm
• Pd = -50 - 10 - 20log(d(m) / 1m)

Policies Pseudocode

Received Power referred to P, base station referered to B.

Threshold referred to T, entrophy referred to E.

Best Policy

if (Pnew > Pold) {
    car.bs = Bnew;
    car.power = Pnew;
}

Threshold Policy

if (Pnew > Pold && Pold < T) {
    car.bs = Bnew;
    car.power = Pnew;
}

Entrophy Policy

if (Pnew > Pold + E) {
    car.bs = Bnew;
    car.power = Pnew;
}

Minimum Policy

if (Pnew < Pmin) {
    car.bs = Bnew;
    car.power = Pnew;
}

Demo Video

What is handoff?

Handoff is the transition for any given user of signal transmission from one base station to a geographically adjacent base station as the user moves around.

Each time a mobile or portable cellular subscriber passes from one cellinto another, the network automatically switches coverage responsibility from one basestation to another. Each base-station transition, as well as the switching processor sequence itself, is called handoff.

Policies parameter value

The different parameters for each policy are listed below.

Parameters	Value
Threshold	-108 dBm
Entrophy	5 dBm
Minimum	-112 dBm

Posssibility of turning

The possibility of changing direction when encountering intersection is listed below.

Intersection with four roads

Direction	Possibility
Go straight	1/2
Turn right	1/3
Turn left	1/6

Intersection with three roads

Direction	Possibility
Turn right	1/2
Turn left	1/2

This project was bootstrapped with Create React App.

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In the project directory, you can run:

npm start

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Your app is ready to be deployed!

See the section about deployment for more information.

npm run eject

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