The correct answer is D. Power of base station.
Multipath is a phenomenon that occurs when a radio signal travels from a transmitter to a receiver via multiple paths. This can happen when the signal is reflected off of objects or when it travels through different media. Multipath can cause a number of effects, including:
- Random frequency modulation: The signal can be distorted by the different paths that it takes to reach the receiver. This can cause the signal to be received at different frequencies, which can make it difficult to decode.
- Time dispersion: The signal can arrive at the receiver at different times, which can cause it to be spread out in time. This can make it difficult to decode the signal.
- Rapid changes in signal strength: The signal can be received at different strengths, which can make it difficult to decode.
The power of the base station is not an effect caused by multipath. The power of the base station is the amount of power that is transmitted from the base station to the receiver. This power is not affected by multipath.
Here are some additional details about each of the effects that can be caused by multipath:
- Random frequency modulation: This is caused by the different paths that the signal takes to reach the receiver. The signal can be reflected off of objects or travel through different media, which can cause it to be distorted. This distortion can cause the signal to be received at different frequencies, which can make it difficult to decode.
- Time dispersion: This is caused by the different paths that the signal takes to reach the receiver. The signal can arrive at the receiver at different times, which can cause it to be spread out in time. This can make it difficult to decode the signal.
- Rapid changes in signal strength: This is caused by the different paths that the signal takes to reach the receiver. The signal can be received at different strengths, which can make it difficult to decode.
Multipath can be a problem for wireless communication systems. It can cause signal distortion, which can make it difficult to decode the signal. Multipath can also cause signal fading, which can cause the signal to be lost. There are a number of techniques that can be used to mitigate the effects of multipath, such as using directional antennas and diversity reception.