# Random Walk

**Random Walk** is a part of Indoor Mobility Models. In Indoor Mobility model, there are 3 parts- Random Walk, Random Way-Point, Random Direction.

Mobility Model is a model that describe the movement of mobile users and how their location, velocity and acceleration change over time. The behavior or activity of a user’s movement can be described using both analytical and simulation models. In this topic, we will discuss Random Walk model.

**Random Walk :**

This model was firstly described by Einstein in 1926. Mobile Node moves from current location to a new location by randomly choosing a direction and speed because it is dynamic. It catches the attribute of minimum speed or maximum speed and direction from 0 to 2pi i.e.,, 360 degree. A constant time interval ‘t’ and distance ‘d’.

There are three types of Random Walk available- 1D, 2D, 3D.

- 2D Random Walk is widely used in mobility.
- It is memory-less mobility pattern.
- Current speed is independent of its past.
- This also generates unrealistic movements such as sudden stops and sharp turns.

Suppose, there is a initial position with a particular angle say, alpha and with some speeds say, 5 m/sec travels to the point 1. Now, node is standing at point 1 then again with some particular angle and with some particular speed, it travels from point 1 to point 2. Then from point 2 to point 3 and so on till it reaches the final position. This whole scenario is known as Random Walk. It is so called because in this the direction, speed and acceleration is also dynamic. Pause time in random walk is 0.

Why is it so ? Because it does not pause or stop and node moves from 1 point to another in no time.

They also have sharp turns see point 5,6,7. Predicting it then seems to be difficult because of the sudden sharp turns they have as it is very steep. This is the main disadvantage of Random Walk. The main advantage is that it is simple to use and can be easily handled flows around complicated boundaries.