EDGE vs. 3G
The critical difference between these two technologies is that EDGE (Enhanced Data rates for Global Evolution or Enhanced Data for GSM Evolution), by definition, is an enhancement to existing GSM networks, using existing GSM frequencies. 3G is seen as a powerful driver for the development of terminals capable of full-web browsing.
EDGE is often referred to as a 2.75G network. It is a further step towards the capacities and capabilities of 3G, offering data speeds that are required for music and videos. EDGE does not, however, offer video telephony.
GSM, GPRS, EDGE, SMS and IM
Globally, 2G drove an explosion in mobile voice services, but it provided only limited data capabilityin the order of 14Kbps or less than a dialup modem at the time.
The introduction of and growing interest in the World Wide Web fueled an increasing demand for higher-speed access on mobile devices. While the providers and standards groups were busy laying grand plans for third-generation (3G) wireless to offer broadband services to mobile users, it was still several years away in terms of technology and investment, so an interim solution was needed.
GSM addressed this by coming up with General Packet Radio Services (GPRS), with practical data rates up to 85Kbps, and Enhanced Data for GSM Evolution (EDGE), with data rates up to 236Kbps (very close to DSL and cable modems at the time). This required some new equipment to be deployed by wireless operators and new phones from vendors. But it did not require new frequency spectrum and was not a radical change in their operations given the performance improvement.
In this same time period, Short Message Service (SMS) was taking off in Europe, initially as a low-cost communications alternative to a voice call, and then more as a cultural habit. The same phenomenon would take place several years later in the United States when a new generation of wireless users raised on instant messaging (IM) started using mobile phones.
3G, HSPA, LTE, Mobile WiMAX and UWB
When 3G standards development started in 1998, residential broadband penetration in the world was relatively low. Speeds typically were in the 256 to 284Kbps range for DSL and cable modems. As a result, the reference point for 3G was to design a system that offered 128Kbps to moving cars, 384Kbps to mobile pedestrians, and 2Mbps to fixed users.
As fixed broadband penetration continued to advance around the world, speeds above 1Mbps became commonplace and made a target like 384Kbps seem obsolete. In reality, 3G was unable to deliver even the target levels of performance due to unexpected wireless performance issues following launch.
As 3G failed to meet the increasing demand for speed, High-Speed Packet Access (HSPA) was introduced to enhance the performance of existing GSM-based cellular systems. This offered the potential for much higher bandwidth for an individual user (in excess of 7Mbps), but at the expense of reduced capacity for other voice and data users.
As a result, operators are rolling out HSPA carefully in their existing service areas and are developing HSPA+ to increase the speed and improve the overall capacity per cell.
3G managed to provide increased bandwidth (about 500Kbps, or less than half a typical cable modem on average). But the improvements were too little to keep pace with user expectations and the need to support bandwidth-hungry rich-media applications. So in the interim, wireless operators have rolled out patchworks of 3G and 3.5G capabilities such as HSPA, with speeds up to 14Mbps.
But these technologies were inefficient stopgap solutions to a larger wave of demand for high-quality mobile broadband services. Users are still unable to get broadband connectivity and internetworking with other users and devices outside of a small set of locations (hot spots) and situations.
The following table compares the theoretical speeds available for EDGE, 3G and HSPA technologies:
1.8 Mbps Maximum upload Approximately 100 Kbps
64 Kbps 384 Kbps
Typically, actual maximum speeds will be in the order of approx 80% of the maximum, whilst average speeds will be in the order of 50% to 60% of the maximum. Factors affecting speeds will be terminal (handset) capability, radio capability (the network), signal strength (how far you are from a network tower), and how many concurrent users are on the cell.
It is also important to remember that network and handset technology is constantly improving and higher speeds can / will become available over time.
Next Generation Standards
Next-generation wireless standards have been on the drawing board since early 2000, but they were given little attention because of the focus on rolling out 2.5G and 3G services. Now that the realization is sinking in that a new solution is needed to service the needs of future users, 4G has gained significant visibility again.
The two competing standards are LTE (Long-Term Evolution) and Mobile WiMAX (the IEEE 802.16e wireless broadband standard).
LTE was developed as a next-generation extension of GSM/UMTS. It supports up to 100Mbps downloads and 50Mbps uploads to mobile users. It uses a technology called Orthogonal Frequency Division Multiple Access (OFDMA) and smart antennas to achieve much higher capacity than 3G systems.
Because over 80% of the world uses GSM, they have a tremendous advantage to build on.
The Mobile WiMAX standard followed a non-traditional development path more similar to WiFi than cellular standards. The initial focus of WiMAX, starting in early 2000, was to create a viable fixed wireless alternative to cable modems and DSL.
The original WiMAX standard was aimed at improving the economics and performance of the previous proprietary approaches by creating an open standard in partnership with key industry players (the WiMAX Forum).
The hope was to achieve economies of scale. The original WiMAX standard (802.16a) was issued in 2003. But as the power of mobility became more apparent with the rapid growth of 2G cellular, the WiMAX standards group and industry partners began to develop a mobile version, WiMAX Mobile (802.16e), issued in December 2005.
The basic standard supports mobile wireless broadband at speeds up to 70Mbps across both licensed and unlicensed bands for a wide range of frequencies, providing much more flexibility and deployment options than cellular.
However, questions still surround WiMAXs range and ability to manage user handoffs versus more proven cellular-based technologies. With Intels agreement to put WiMAX chipsets into new laptops, the introduction of WiMAX-capable handsets from Samsung, and commitments by service providers like Sprint, Clearwire, and several international players, WiMAX has the makings of a formidable competitor for future wireless broadband networks.
The key will be developing an ecosystem of devices, like cameras and media players, and applications like mobile entertainment and virtual conferencing, that leverage this network.
Comparison of LTE and WiMAX
Peak Download Speed 100Mbps 70Mbps Peak Upload Speed 50Mbps 5 to 10Mbps
Average Range 30+ miles /48+ km 5+ miles /8+ km
LTE Advanced and 802.16m are expected to push both of these technologies up to 1Gbps in the next iteration of each standard. Given the huge uncertainty in deployment costs and actual performance, it is tough if not impossible to pick a winner. It is possible that a new disruptive solution will come from left field, such as Ultra Wideband (UWB) to stake out the 4G opportunity.
Wireless vs wireline
Given the information above it may sound logical that wireless channels would reach the same level of speed as wireline broadband, however physical limitations make this nearly impossible.
The speed of a given connection depends on the amount of spectrum or frequency available, as well as the signal-to-noise ratio.
As a point of comparison, fiber-optic lines have the most spectrum and the lowest noise level. The signal is transmitted via light over glass, so very little natural interference occurs.
The figure below shows the continuous gap when comparing the progression of speeds in residential broadband channels (from DSL to cable modem to fiber) to wireless broadband (from 1G to 4G).
Comparison of wireless and wireline connection speeds
This is primarily due to the fact that wireless transmits through an extremely variable environment and is susceptible to the following degradations:
- Multipath, in which multiple versions of the same signal
collide with buildings and other objects
- Fading, in which the user moves behind objects or away
from the transmitter
- Signal path loss due to atmospheric effects (e.g. water)
- Interference from other wireless channels
Furthermore, the cellular environment comprises many areas of coverage through which the user travels, entering and leaving coverage of the various cells.
Intelligent mobility management techniques such as cell selection and handover are used to mitigate the impacts of such user mobility, but these also consume more resources, taking away from bandwidth to the user.
The true equalizer between wireline and wireless environments is mobility, which makes the overall convenience and utility of wireless a winner.
Source: Niven Anghar