Assignment:
The frequency band 870 - 890 MHz is used for analog (FM) cellular telephone systems. A base station transmits a signal with a power of 1 watt to an antenna with a gain of 10 dB. The signal is received by a cell phone 2 km away with an antenna gain of 0 dB.
a. For the path length of 2.0 km, calculate the free space path loss in dB at a frequency of 880 MHz, assuming line of sight (LOS) conditions between the base station and the cell phone.
b. Calculate the power at the input to the cell phone receiver, in dBW. Set your answer out as a link budget and include 3 dB miscellaneous losses.
c. The cell phone receiver has a system noise temperature of 450 K and a noise bandwidth of 30 kHz. Calculate the noise power and carrier to noise ratio (CNR) in the receiver.
d. The threshold carrier to noise ratio (CNR) for successful reception of the FM signal is 20.0 dB. What is the link margin under line of sight (LOS) conditions? Under what conditions might the margin be reduced to 0 dB, or the CNR at the receiver fall below 20 dB?
Provide complete and step by step solution for the question, use formulas.