FDMA
FDMA is the oldest and most familiar method of radio communication
• used since 1890 in broadcasting, two-way radio, and cellular systems
Each user has a private frequency for the duration of their call
Distant users are far enough that they cause no interference
When the call is finished, the channel is released and available for a new call FDMA is the method used in the original cellular systems
• “AMPS” Advanced Mobile Phone System.
TDMA
Each user has a specific frequency but only during an assigned time slot. The frequency is used by other users during other time slots.
INTERNATIONAL VERSION
GSM: Groupe Special Mobile
Developed in Europe, used in roughly 50% of all wireless systems
worldwide.
8 timeslots, 7 or 8 users occupy in rotation