Dear Rohit,

welcome,

Conceptually if you have a wireless transmitter , and it is require to cover specific area by this transmitter, then the transmitted power depends on the required received signal power, the distance of propagation and propagation medium and the radial sector to be covered. Assume the required transmitted per solid angle Psa, and assume the angle to be covered is Theta, Then the power required to cover a solid angle Theta= Psa x theta.

In case of broadcast and multicast the radiation is omnidirectional and the coverage solid angle is  4 pi, while, incase of uni cast the radiation can be made directional with a solid angle Theta unicast which cam be made much smaller than omnidirectional radiator with 4 pi radiation angle. 

Therefore, the multicast and broadcast can  need appreciably larger transmit power than unicast case if the unicast can use directional antennas.If they all use omnidirectional antennas then they will need the same transmit power irrespective of the transmission mode.

For more information please refer to the link:https://www.cise.ufl.edu/~sahni/papers/sensors.pdf

Best wishes

Best wishes

I agree with Sir Zekry that It depends on antenna with omnidirectional antennas  they will need the same transmit power irrespective of the transmission mode whereas multicast and broadcast can  need appreciably larger transmit power than unicast case if the unicast can use directional antennas.

You should first find out if your sensor PHY or MAC layers even differentiate between unicast, multicast, and broadcast.