EDGE - digital wireless technology for mobile communications, which functions as an add-on 2G and 2.5G (GPRS)-networks. This technology works in TDMA and GSM networks. To support EDGE in GSM network requires certain modifications and improvements. 
In addition to GMSK, EDGE uses 8PSK modulation, for five of the nine coding schemes (MCS). EDGE gets a 3-bit word for every change in carrier phase. This is effective (on average 3 times in comparison with GPRS) enhances the overall speed of afforded GSM. EDGE, like GPRS, uses an adaptive algorithm for adjusting the change of modulation and coding scheme (MCS) in accordance with radio quality, which affects, respectively, the speed and stability of data transmission. In addition, EDGE is a new technology which was not in GPRS - Incremental Redundancy (incremental redundancy) - whereby instead resend corrupted packets sent additional redundant information, which is stored in the receiver. This raises the possibility of correct decoding of the damaged package. 
EDGE provides data transfer rates up to 474 kbit / s packet switching matching thus requirements ITU (International Telecommunication Union) networks 3G. This technology has been adopted as part of the ITU IMT-2000 family of standards for 3G. It also expands JavaScript switched data transmission channels HSCSD, increasing the bandwidth of the service. 
Dining EDGE: 
1) ECSD - via CSD 
2) EHSCSD - via HSCSD 
3) EGPRS - via GPRS 
Although EDGE is not required that changes in the hardware of NSS-GSM-network to be subjected to upgrading the base station subsystem (BSS) - must be set transceivers supporting EDGE (8PSK-modulation), and to update their software. Also required and phones themselves, providing hardware and software support modulation and coding schemes used in EDGE.