Enhanced Data rates for GSM Evolution, or EDGE, is a digital mobile phone technology which acts as a bolt-on enhancement to 2G and 2.5G General Packet Radio Service (GPRS) networks. This technology works in TDMA and GSM networks. EDGE (also known as EGPRS) is a superset to GPRS and can function on any network with GPRS deployed on it, provided the carrier implements the necessary upgrades.
EDGE provides Enhanced GPRS (EGPRS), which can be used for any packet switched applications such as an Internet connection. High-speed data applications such as video services and other multimedia benefit from EGPRS' increased data capacity.
In addition to GMSK (Gaussian minimum-shift keying) EDGE uses 8PSK (8 Phase Shift Keying) for its upper five of the nine modulation and coding schemes. EDGE produces a 3bit word for every change in carrier phase. This effectively triples the gross data rate offered by GSM. EDGE, like GPRS, uses a rate adaptation algorithm that adapts the modulation and coding scheme (MCS) due to the quality of the radio channel, and thus the bit rate and robustness of data transmission. It introduces a new technology not found in GPRS, Incremental Redundancy, which, instead of retransmitting disturbed packets, sends more redundancy information to be combined in the receiver. This increases the probability of correct decoding.
EDGE can carry data speeds up to 236.8 kbit/s for 4 time slots (theoretical maximum is 473.6 kbit/s for 8 time slots) 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 also. EDGE has been introduced into GSM networks around the world since 2003, initially in North America.
EDGE is actively supported by GSM operators in North America. Some GSM operators elsewhere view UMTS as the ultimate upgrade path and either plan to skip EDGE altogether or use it outside the UMTS coverage area. However, the high cost and slow uptake of UMTS (as demonstrated by the upstart network 3) have resulted in fairly common support for EDGE in the global GSM/GPRS market.
Although EDGE requires no hardware changes to be made in GSM core networks, base stations must be modified. An EDGE compatible tranceiver unit must be installed and base station system needs to be upgraded to support EDGE. New mobile terminal hardware and software is also required to decode/encode using the new shift keying scheme.
Whether EDGE is 2G or 3G depends on implementation. While Class 3 and below EDGE devices clearly are not 3G, class 4 and above devices perform at a higher bandwidth than other technologies conventionally considered as 3G (such as 1xRTT). With a maximum bandwidth of 236,8 kbit/s at Class 10, EDGE transcends both common 2G and 3G definitions.
Enhanced Data rates for Global Evolution (EDGE)又称改进数据率GSM服务， 是一种数字移动电话技术，作为一个2G和2.5G (又名GPRS)的延伸，有时被称为2.75G。这项技术工作在TDMA和GSM网络中。 EDGE (通常所说 EGPRS)是GPRS的扩展，可以工作在任何已经部署GPRS的网络上。 (只要设备做一些必要的升级)
In addition to 除了它的九层模型的上5层使用GMSK （高斯最小移位键控）EDGE 之外它还可以使用8PSK (8相位移相键控)作为编码方案。 EDGE is producing a 3bit word for every change in carrier phase. 这你能提供GSM3倍的数据吞吐量。 跟GPRS一样，EDGE使用速率匹配算法调整调制编码方案 (MCS)，因此能保证无线信道，数据流量和数据传输的稳定。 它引入了GPRS里没有的新技术：增加冗余度代替中继干扰报文发送更多的冗余信息来保持与接收机的联络。这样能增加正确解码的概率。
在报文模式，它的最高数据数率是384Kbps，因此符合ITU对3G网络的要求。作为IMT-2000家族的3G标准的一部分被ITU接受。 它还加强了电路交换模式，使用被叫作 HSCSD的技术提高数据交换速率。EDGE大约在2003年最初由北美引入GSM网络。
由于GSM/GPRS的强烈竞争对手CDMA2000，到2004年, EDGE主要在北美的运营商那里部署了部分。大部分运行商把UMTS作为理想的升级途经，计划完全跳过EDGE或者在UMTS覆盖不到的区域使用。然而，UMTS高昂的建设费用和缓慢的实施已经使一些西欧的运营商采用EDGE作为过渡阶段的升级方案。 (典型的运行商3)
EDGE的状态位于2G或者3G取决于设备。Class 3 和更低级别的设备并不是3G，Class 4和以上级别的设备性能能提供高于通常认为的3G设备的带宽，Class 10能提供230k的带宽, EDGE超过普通2G和3G的定义。