EDGE

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Enhanced Data rates for Global Evolution (EDGE) is a high-speed mobile data standard that allows data transmission speeds of up to 200 kbps to be achieved. The “G” in EDGE previously stood for “GSM” but was changed to “Global” when the TDMA network community adopted EDGE as part of its roadmap to 3G.

EDGE was initially developed (by Ericsson) for GSM mobile network operators who fail to win Third Generation (3G) spectrum. It was soon realized that EDGE would also work on TDMA networks. EDGE can also provide an evolutionary migration path to 3G by making the changes in modulation that will be necessary for implementing 3G later. The idea behind EDGE is to eke out even higher data rates on the current 200 kHz GSM radio carrier by changing the type of modulation used, whilst still working with current circuit (and packet) switches.

	Applications
	Data Transfer Rate
	Technical

Applications

Multiplayer Games: Because of the higher speeds, its possible to play online with another player, playing on another phone in a different location. When player A makes a move on his phone, it is seen on player B’s phone, and vice versa. It is much more fun, because you are playing with another human being, and so the game and the outcome is that much unpredictable.

Live TV: Live TV streaming is still a new concept in most countries (in the few networks where it has been deployed), the experience depends on the bandwidth available. Equally important is the RF tuning and optimization done at the BTS level, which can perceptibly change the user experience.

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Data Transfer Rate

The highest theoretical throughput with EDGE is 384Kbps when all eight timeslots are used. This means a maximum bit rate of 48 kbps per timeslot- higher per timeslot any other previously available mobile data services. However, the estimated actual throughput is up to 70Kbps.

EDGE uses a new modulation technique called 8PSK (Eight phase shift keying) across the air interface on a GSM network. This new modulation gives a theoretical throughput of 48Kbps per timeslot which when multiplied by the maximum 8 timeslots gives the maximum theoretical throughput of 384Kbps. Currently this standard is still in development and there are no EDGE networks or terminals. It is anticipated that data rates will realistically be offered at between 50 to 70Kbps give network capacity and terminal constraints.

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Technical

Both High Speed Circuit Switched Data (HSCSD) and GPRS are based on something called Gaussian Minimum Shift Keying (GMSK) that only yields a moderate increase in data bit rates per time slot. EDGE on the other hand is based on a new modulation scheme that allows a much higher bit rate across the air interface. This modulation technique is called eight-phase-shift keying (8 PSK). It automatically adapts to radio circumstances and thereby offers its highest rates in good propagation conditions close to the site of base stations. This shift in modulation from GMSK to 8 PSK is the central change with EDGE that prepares GSM and TDMA networks for 3G

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