Advanced explanation:
EDGE is a further development of GPRS and is also known as 2.5G. It increased data rates up to 384 kbps by using a more advanced modulation technique called 8PSK (Phase Shift Keying). EDGE allowed for higher spectral efficiency, which meant that more data could be transmitted per hertz. Although EDGE is slower than 3G, it was an important technology to improve data transmission on 2G networks and allow more users to access the mobile internet.
Example:
With EDGE, you could download simple music files and pictures faster on an early mobile phone than with GPRS, although the speed was still far below that of 3G.