Enhanced Data Rates for GSM Evolution
The last change to a 2G GSM system on the road to 3G is the implementation of enhanced data rates for GSM evolution (EDGE). It was once believed that EDGE could be more than enough for 3G systems. That view has changed dramatically as multi-megabit air interfaces have been developed and video to mobile handsets has become a reality.
As designed, EDGE provides both circuit-switched and packet-switched capabilities. The speed increase comes from replacing the 14.4 kbps per time slot GMSK modulation with 8 phase shift keyed (8PSK) modulation that provides 48 kbps per slot. With 48 kbps per slot, the assignment of eight time slots for a data channel results in a maximum data rate of 384 kbps.
EDGE gives the service provider increased data rates but it will never get to the megabit range.