Cellular Phones and Base Stations

• When a cellular phone is used, signals containing a user's message travel between the antenna of the cellular phone and the antenna of a base station.
• These signals are called electro-magnetic waves.
• Antennas of base stations are often mounted on top of buildings or poles along major traffic routes.
• Those antennas look like grey, rectangular boxes.
• Question:If two cellular phones communicate with the same base station, how can the base station separate the two signals?
  
    

  Figure 2.1: Cellular Phones and Base Station