Enhanced Data Rates for GSM Evolution

Enhanced Data Rates for GSM Evolution
EDGE or Enhanced Data rates for GSM Evolution is a technology evolution of GSM and IS-136. The purpose of this new technology development is to increase the speed of data transmission, spectral efficiency, and enable the use of new applications and increased capacity.
Application of EDGE in GSM phase 2 + such as GPRS and HSCSD is done by adding a new physical layer at the side of the Radio Access Network (RAN). So there is no berubahan on the side of the core network such as MSC, SGSN, or GGSN. EDGE Capacity For Advanced Technology Data Transfer Rate
GPRS offers data speeds of 115 kbps, and in theory can reach 160 kbps. While at EDGE data speeds sbesar 384 kbps, and in theory can reach 473.6 kbps. In general, the speed of EDGE is three times higher than GPRS. This is possible because the modulation technique used EDGE (EDGE uses 8PSK, GPRS uses GMSK) and different methods of fault tolerance with GPRS, and also an improved link adaptation mechanisms. EDGE also uses a different coding scheme with GPRS. In the EDGE coding scheme known as 9 kinds, while there are only 4 in the GPRS coding schemes.
Overview History of EDGE Technology
EDGE has developed from several previous generations. The development of this technology is preceded by the AMPS as a first generation mobile communication technology in 1978, up to now (in 2006), its development has reached the 4th generation technology, although still in the stage of research and testing. GSM itself as one of the second generation mobile communication technology, is a technology that is currently the most widely used in various countries. In its development, GSM is capable of delivering voice communications and low speed data (9.6 - 14.4 kbps), then evolved into a GPRS capable of delivering voice and data with better speed, 115 kbps.
In the next phase, the increasing need for a mobile communication system capable of delivering data with higher speeds, and to answer this need then diperkenalkanlah EDGE (Enhanced Data rates for GSM Evolution) is capable of delivering data at speeds up to 3 times the speed of GPRS, which is 384 kbps.
In further development, diperkenalkanlah third-generation technology, one of which UMTS (Universal Mobile Telecommunications Service), which is capable of delivering data at speeds up to 2 Mbps. With speeds of up to 2 Mbps, UMTS network to serve multimedia applications (video streaming, Internet access or video conferencing) via mobile devices quite well. Developments in mobile telecommunications world is believed will continue to grow, until eventually introduced new technologies better than that available today. Lately, scientists are trying to develop mobile telecommunication technology with a very wide range, high mobility rate, integrated services, and berbasikan IP (Mobile IP). This technology was introduced with the name "Beyond 3G" or 4G.

Capacity and Capability EDGE For Mobile Technology Third Generation (3G)
As already mentioned in the previous point, EDGE has the data transfer, for example, EDGE technology can be three times faster than GPRS technology. That is, if the mobile subscriber wants to download a MMS with GPRS technology takes tens of seconds, but with EDGE technology, it only takes a few seconds.
Another advantage, if the GPRS technology has the ability to transfer data at up to 114 Kbps, EDGE technology capable of supporting data, multimedia services up to 384 Kbps. EDGE is a new designation for GSM 384. This technology is called GSM 384, because it has a data transmission capability of up to 384 Kbps.
According to the World Association GSM, EDGE can even reach speeds of up to 473.8 kbps. With EDGE, mobile operators can provide data communication services at speeds higher than GPRS, where GPRS is only capable of sending data at speeds of about 25 Kbps. So also when compared to other platforms, EDGE capability is 3-4 times the speed of telephone wire line access (usually around 30-40 kbps) and nearly 2 times the speed of CDMA 2000 1x is only about 70-80 kbps. About the services provided this technology, namely the various applications of third generation services that high-quality streaming audio, streaming video, games on line, high speed download.
Implementation of EDGE
As the name suggests, EDGE (Enhanced Data rates for GSM Evolution), is a technology developed with the basic technology for GSM and GPRS. An EDGE system was developed by still using the devices contained in the GSM / GPRS network. So EDGE can not own. A GPRS system consists of SGSN (Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node), which is a network corenya, which added to a GSM network. While on the radio, a GPRS network requires the addition of PCU in GSM radio device before. The figure below shows the general diagram of the GPRS network.
Implementing EDGE on the existing GPRS network requires only additions to the radio access side only. While on the side of the core network, EDGE uses the same device and protocol to that used in previous GPRS network. GPRS and EDGE network differences found only in akssnya radio side only, while the core network side, EDGE and GPRS using the same tools and protocols. A GPRS network can be upgraded into a network with EDGE system by simply adding an EDGE Transceivier Unit (TRU) on the side of the radio access.

EDGE Speeds Process
EDGE is a way to increase data speeds on GSM radio link. By using the technique of modulation and coding schemes that are different from the previous GPRS system, and by doing the settings on his radio link protocols, EDGE offers a capacity that is significantly greater than that possessed by the GPRS system. So in general there are three aspects of new techniques on EDGE if we compare with the GPRS, namely

    Modulation Technique
    Coding Techniques
    Radio Access Network (RAN)

In the EDGE modulation
To obtain higher transfer speeds than GPRS uses GMSK modulation (Gausian Minimum Shift Keying), EDGE uses a different modulation technique with GPRS namely 8PSK (8-Phase Shif Keying). The figure below shows the visualization of GMSK modulation on GPRS and EDGE are described 8PSSK at pasa a diagram of I / Q, where I is the real axis and Q is the imaginary axis.
By using 8PSK modulation, a symbol is encoded using 3 bits, while in GMSK a symbol is encoded with 1 bit. Because GMSK and 8PSK symbols have the same level, namely of 270 ksimbol / s, then the overall level of 8PSK modulation will be 3 times larger than GMSK, amounting to 810 kb / s.
Based on the explanation above, the distance between the symbols on the 8PSK is shorter than the distance between the symbols on the GMSK, because the ad-8 8PSK symbol in GMSK sedengkan there are only 2 symbols. Shorter distances between the symbols resulted in a large signal level between one symbol with another symbol is more difficult to distinguish. So the risk of error is greater.
On the radio signal conditions is quite good, the difference in distance between this symbol does not significantly affect the quality of data being transmitted. At the time of the radio signal a bad condition, it would require the addition of extra bits that will be used as a correction of errors, so that incorrect data is received could be improved. So the quality of data on EDGE is not inferior to the quality of data on GPRS using MPSK. Moreover, the EDGE is also used MPSK modulation is used in CS1 to CS4 - his, and also in EDGE is the process of "adjustment package" that can change the type of CS that is used when there is a mistake in the data sent.
Encoding Technique On EDGE
On EDGE known nine kinds of coding techniques, namely MCS (Modulation Coding Scheme) from 1 to MCS9. While in GPRS only used 4 pieces of coding techniques, namely CS (Coding Scheme) from 1 to sc4. Four of the first coding technique on EDGE, MCS1 until MCS4, using GMSK modulation, the same as that used in GPRS. Whereas 5 other coding techniques, MCS5 until MCS9, using 8PSK modulation.
Both the GPRS or EDGE, the level of the higher coding schemes offering higher data speeds as well but in addition, more tingggi level encoding scheme, then the lower the resistance to error. That is, the higher speed data packet, then the easier the data packet that has errors in its delivery. This is because, the higher level encoding scheme, then the level of the mechanism of "error correction" which used the lower.
Although MCS1 until MCS4 on EGDE alike use GMSK modulation, such as CS1 to CS4 on GPRS, but both have different speeds. This is because of the use of different headers. In EDGE, the data packet contains a header which allows for data packets resegmentasi. That is, if a data packet sent using a high-level coding scheme (higher speed, less error correction) and data was not well received at the receiver side.
After a retransmission request (retransmission) packet data received was incorrect, the next delivery, the encoding scheme used can be changed and adapted to the conditions of the radio interface. That is, on the next delivery, packet data will be sent using a lower coding scheme, which has a mechanism for better error correction. So expect at this second delivery data were well received at the receiver side.
Unlike GPRS, resegmentasi data packets can not be done. Therefore, when a data packet has been sent using a particular encoding scheme. So although the data is received either at the receiver side, when the next shipment, the data will still be sent using the same encoding scheme. So it is likely that any data packet received at the receiver side is still as large as when the first shipment. Therefore, it can achieve a balance between speed and quality of data being transferred.
EDGE Technology Development In Indonesia And Its growth in the Future
In Indonesia, EDGE technology has evolved over the last few years since EDGE. The development of GSM technology in Indonesia is rapidly rolling starting with the deployment of simultaneous dual band (GSM 900 and 1800) and the continued deployment of GPRS simultaneously, has successfully brought the industry into the phase of 2.5 is not felt. Not long ago rolled 2.5 G technology, 3G technology was born that brought revolution in the Indonesian cellular technology. Some providers in Indonesia, Indosat, Telkomsel and Excelcomindo are competing to create new innovations and brought the 3G technology. Many Indonesian people, especially for those living in big cities deperti Jakarta, Bandung, Medan and Surabaya, which use the available 3G services such as video calls, download content, high speed internet access, etc..
After about 2 years now introduced 3G in Indonesia has emerged evolution of 3G known as HSDPA or 3.5 G. HSDPA or High Speed ​​Downlink Packet Access is a technology that runs on the 3G platform on a new channel called High Speed ​​Downlink Shared Channel (HS-DSCH). With HDSPA, downlink speeds can theoretically reach 3.6 Mbps compared to 3G which only reached 384 Kbps. Because it is still running on the 3G platform, but with the speed exceeds the speed of 3G technology standard is referred to as 3.5 G. Actually the development of 3G HSDPA technology on the development of technology is almost similar to EDGE or Enhanced GPRS (EGPRS) on GPRS. Please note, EDGE has reached 236 Kbps downlink speed, fast enough when compared to the GPRS standard which has a speed of about 50 Kbps. Because it is also EDGE or GPRS technology, also known as 2.75 G. technology