Tech Primer

Enhanced Data for GSM Evolution (EDGE)

What is an EDGE network?

Enhanced Data for GSM Evolution (EDGE) is a technology that boosts GSM’s capacity to handle services for the third generation of mobile telephony. It offers three times the data capacity of GPRS. Using EDGE, operators can handle three times as many subscribers, triple their data rate per subscriber, or add extra capacity to voice communications. It uses the same TDMA (Time Division Multiple Access) frame structure, logic channel and 200 kHz carrier bandwidth as today’s GSM networks leaving existing cell plans intact. EDGE is a radio-based high-speed mobile data standard that can be integrated into GSM /GPRS and IS-136 networks.

How does it work?

EDGE is intended to build upon enhancements provided by GPRS (General Packet Radio Service) where packet switching is applied to a cellular network. It enables a three-fold increase in the speed of data transmission by adopting a new form of modulation. GSM uses Gaussian Minimum Shift Keying (GMSK), while EDGE changes the modulation to 8-phase shift keying (8-PSK) thereby providing a significant increase in data rates. (8-PSK enables each pulse to carry 3 bits of information versus GPRS 1 bit per pulse rate)

What does a service provider need to implement EDGE?

EDGE systems require an EDGE transceiver unit to be added to each cell along with software upgrades that permit its use. These software upgrades may be implemented remotely. The inclusion of EDGE in a network requires significant investments and as a result, these upgrades will normally be implemented over a period of time. However GSM, GPRS and EDGE can all co-exist on the same network. EDGE requires higher radio signal quality than that found in an average GSM network for higher data throughput to be achieved. This means more base stations (especially indoors) and infrastructure build-out for established GSM operators wishing to migrate to EDGE.

What is EDGE’s advantage?

EDGE will boost all existing circuit and packet switched services and new high-speed data applications will be launched on this platform. It also helps data capacity to be deployed on demand, minimising the investment required. All mobile services benefit from EDGE that enables seamless coverage and capacity extension for 3G like services such as streaming, high-quality audio or video clips, multimedia messaging, full-fledged mobile web browsing and access to corporate data.

Are WCDMA and EDGE complementary technologies?

EDGE and WCDMA are complementary in nature. Together they will sustain an operator’s need for third generation network coverage and capacity nationwide. Enhancing a GPRS network is accomplished through evolution with EDGE within the existing spectrum and by deploying WCDMA (Wideband Code Division Multiple Access) in the new frequency band. Rolling out two technologies in parallel will help telcos offer high-speed data services with lower capital expenditure.

What is the future of EDGE?

It can satisfy increased data demand and enhance revenues especially in urban and office environments for business users and then provide wider area coverage as private usage takes off. The next evolutionary step for the EDGE includes enhanced service provisioning for packet switched networks and increased alignment with service provisioning in UMTS.

Who’s offering EDGE services in India?

AirTel, Hutch-Orange and IDEA Cellular.