GSM Mobile Network – mobile network of 2nd generation
EDGE Data Transmission in GSM Network

A data transmission technique in 2.75G of mobile networks, denoted as EDGE (Enhanced Data Rates for GSM Evolution), increases the network capacity and available transfer rates in the context of HSCSD and GPRS techniques. The improvement of data transmission through more potential coding or by utilization of more timeslots is no longer an option. The only possible method to further increase of the throughput is achieved by the utilization of more efficient modulation technique. Thus instead of the original GMSK (Gaussian Minimum Shift Keying) modulation, the EDGE uses eight level phase modulation, 8-PSK (Phase Shift Keying),

Data transmission through EDGE

The symbol rate at one frequency channel with a width of 200 kHz is the same as before, i.e., 270.833 ksymbols/s. Nonetheless, by utilization of eight level modulation schemes, the bit rate is now three times higher comparing to the original binary modulation. The maximum theoretical reachable transfer rate is 473.6 kbps (59.2 kbps per time slot). However, this is available only if all 8 slots are employed and conditions for signal propagation are favourable.

Deployment of this technology requires implementation of a new type of transceivers to the network. This change must be applied in each cell, where new technology will be deployed. The next step is an adjustment related primarily to update its own software. Combination of EDGE technology along with GPRS and HSCSD technologies seems to be very convenient, especially for widespread transmission the new modulation method principle brings significant acceleration of data transfers. A common deployment arise principles called as ECSD (Enhanced Circuit Switched Data) and EGPRS (Enhanced General Packet Radio System). EDGE is generally considered as a last step in improvement of the original GSM system before the introduction of the third generation called as UMTS.