EDGE - Enhanced Data rates for GSM Evolution

Enhanced Data rates for GSM Evolution [EDGE] or Enhanced GPRS [EGPRS], is a digital mobile phone technology that allows increased data transmission rates and improved data transmission reliability.

Although technically a 3G network technology, EDGE is typically classified as the unofficial standard 2.75G, due to its slower network speed.

EDGE technology increases the capacity of GSM to handle services for the third generation of mobile telephony. Using EDGE, operators can support three-times more subscribers than GPRS, by either tripling their data rate per subscriber, or adding extra capacity to their voice communications.

EDGE uses the same TDMA [Time Division Multiple Access] frame structure, logic channel and 200kHz carrier bandwidth as today's GSM networks, which allows existing cell plans to remain intact.

EDGE Deployments

EDGE has been introduced into GSM networks since 2003, and can be used for any packet switched application, such as:

• Internet connection
• High-speed data applications - video services and other multimedia
• Interactive applications

EDGE Evolution continues in Release 7 of the 3GPP standard providing doubled performance e.g. to complement High-Speed Packet Access [HSPA].

EDGE/EGPRS is easy for existing GSM carriers to upgrade, being implemented as a bolt-on enhancement for 2G and 2.5G GSM and GPRS networks.

Although EDGE requires no hardware or software changes to be made in GSM core networks, base stations must be modified. EDGE compatible transceiver units must be installed and the base station subsystem [BSS] needs to be upgraded to support EDGE.

New mobile terminal hardware and software is also required to decode/encode the new modulation and coding schemes and carry the higher user data rates to implement new services.

EDGE Circuit Switched is a possible future development.

Transmission

EDGE uses both:

• Gaussian minimum-shift keying [GMSK], and
• PSK/8 phase shift keying [8PSK] for the upper five of its nine modulation and coding schemes.

EDGE produces a 3-bit word for every change in carrier phase. effectively increasing the gross data rate offered by GSM by 300 percent.

Like GPRS, EDGE uses a rate adaptation algorithm that adapts the modulation and coding scheme [MCS] according to the quality of the radio channel, and thus the bit rate and robustness of data transmission.

It introduces Incremental Redundancy, a new technology [not found in GPRS] , which, instead of retransmitting disturbed packets, sends more redundancy information to be combined in the receiver. This increases the probability of correct decoding.

Transmission Rates

EDGE can carry data speeds up to 236.8 kbit/s for 4 timeslots [theoretical maximum is 473.6 kbit/s for 8 timeslots] in packet mode and will therefore meet the International Telecommunications Union's requirement for a 3G network, and has been accepted by the ITU as part of the IMT-2000 family of 3G standards. It also enhances the circuit data mode called HSCSD, increasing the data rate of this service.

Classification

Whether EDGE is 2G or 3G depends on implementation:

• Class 3 and below EDGE devices are not 3G
• Class 4 and above devices perform at a higher bandwidth than other technologies conventionally considered as 2G as 1xRTT).

Because of the variability, EDGE is generally classified as 2.75G network technology.

EDGE Evolution

EDGE Evolution improves on EDGE by:

• Latencies are reduced by lowering the Transmission Time Interval by half (from 20 ms to 10 ms).
• Bit rates are increased up to 1 MBit/s peak speed and latencies down to 100 ms using dual carriers
• Higher symbol rate and higher-order modulation (32QAM and 16QAM instead of 8-PSK)
• Using Turbo codes improve error correction.
• Signal quality is improved using dual antennas

An EDGE Evolution terminal or network can support some of these improvements, or roll them out in stages.

EDGE Networks

EDGE is actively supported by GSM operators in North America. Some GSM operators planned to skip EDGE and proceed directly to UMTS a upgrades, sometimes deploying EDGE outside the UMTS coverage area. The high cost and slow uptake of UMTS has delayed most UMTS upgrades, driving more support for EDGE in the global GSM/GPRS market.

USA EDGE Networks

• Alltel
• AT&T Mobility
• Centennial Wireless
• Chinook Wireless
• Cincinnati Bell
• Corr Wireless
• Edge Wireless
• i wireless
• Mid-Tex Cellular
• Petrocom
• Plateau Wireless
• PSC Wireless
• Suncom
• T-Mobile
• Unicel
• Viaero
• Westlink
• XIT Communications

United Kingdom EDGE Networks

• Telefónica O2 - currently upgrading to support iPhone.
• Orange
• T-Mobile
  

Australasia EDGE Networks

Australia

Telstra has nationwide EDGE coverage (approximately 96% of population).

New Zealand

Vodafone NZ - Nationwide EDGE coverage across main metropolitan areas, for corporate and industrial use only. New Zealand's public use only available via Australia's Telstra network.

Samoa

Digicel Pacific (previously Telecom NZ) is still under initiation.

Fiji

Vodafone (Fiji) and Digicel Pacific has no EDGE service.

Back To Top

Mobile Index | GSM | EDGE | CDMA | WCDMA | SIMs | Mobile OS | Mobile Apps | Mobile Video | Global Cellphone | Mobile Desktop | Device Market Share | Motorola Roadmap | Cingular Roadmap | Sprint Roadmap | Verizon Wireless Roadmap