$($Trying to do this in MATLAB and struggling$)$Extra Credit: Simulation of Mobility Models $(20$ points$).$ Assume that a $3$x$3$ grid $($cell$)$ is used

to represent a geographical area, and $20$ mobile users follow a mobility model, exploration and preferential

return model with probability moving to new location $($neighboring cells$)$ with probability $P_{\text{n}\text{e}\text{w}}=S^{-},$

where $=0\mathrm{.}2,S=2,$ and $=0\mathrm{.}5.$

Draw one figure with the trajectory of all mobile users for $100$ time slots with respect to $9$ cells, and one

figure with the probability density function, which is the statistical analytic of all users in each location.

Note: the initial location can be randomly chosen, which can be a Poisson Point distribution, if matlab

or $C++$ is used as your coding language; otherwise, rand can be used. Once a location $($or a cell$),$ then

it should be recorded a mobile station's buffer as a previously visited location such that it will be

considered as $P_{\text{r}\text{e}\text{t}}=1-S^{-}$ a preferable return point rather than a new location.