Problem #$1$:

In a $3G$ network, a connected mobile is moving from NodeB$1($serving base station$)$ to NodeB$2($new base station$).$ A mobile is served by two base stations if the ratio between the power received from NodeB$2$ to the power received from NodeB$1$ exceeds $70\%.$ Then, one of the two serving base stations will be dropped, if the ratio of the power received from one of them $($NodeB$1)$ to the other one $($NodeB$2)$ decreases below $50\%.$ Assume the distance between the two base stations is $400$ meters, the power measured at $d_0=20$ is $7dBm$ and the path loss exponent is $3.$

a$)$ Determine the distance from NodeB$1$ at which two base stations will start serving the Mobile Terminal.

b$)$ Determine the Power received from NodeB $1$ at that distance

c$)$ Determine the Power received from NodeB$2$ at that distance

d$)$ Verify the ratio