This Tech article covers basic concepts about Fourth Generation Communication Standards
In telecommunications, 4G is the fourth generation of mobile phone mobile communications standards. It is a successor of the third generation (3G) standards. A 4G system provides mobile ultra-broadband Internet access, for example to laptops with USB wireless modems, to smartphones, and to other mobile devices. Conceivable applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television and Cloud Computing.
Two 4G candidate systems are commercially deployed: the Mobile WiMAX standard (at first in South Korea in 2006), and the first-release Long Term Evolution (LTE) standard (in Oslo, Norway since 2009). It has however been debated if these first-release versions should be considered to be 4G or not, as discussed in the technical definition section below.
In the U.S., Sprint Nextel has deployed Mobile WiMAX networks since 2008, and MetroPCS was the first operator to offer LTE service in 2010. USB wireless modems have been available since the start, while WiMAX smartphones have been available since 2010, and LTE smartphones since 2011. Equipment made for different continents are not always compatible, because of different frequency bands. Mobile WiMAX are currently (April 2012) not available for the European market.
In March 2008, the International Telecommunications Union-Radio communications sector (ITU-R) specified a set of requirements for 4G standards, named the International Mobile Telecommunications Advanced (IMT-Advanced) specification, setting peak speed requirements for 4G service at 100 megabits per second (Mbit/s) for high mobility communication (such as from trains and cars) and 1 gigabit per second (Gbit/s) for low mobility communication (such as pedestrians and stationary users).
Since the first-release versions of Mobile WiMAX and LTE support much less than 1 Gbit/s peak bit rate, they are not fully IMT-Advanced compliant, but are often branded 4G by service providers. On December 6, 2010, ITU-R recognized that these two technologies, as well as other beyond-3G technologies that do not fulfill the IMT-Advanced requirements, could nevertheless be considered “4G”, provided they represent forerunners to IMT-Advanced compliant versions and “a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed”.
Mobile WiMAX Release 2 (also known as WirelessMAN-Advanced or IEEE 802.16m’) and LTE Advanced (LTE-A) are IMT-Advanced compliant backwards compatible versions of the above two systems, standardized during the spring 2011, and promising speeds in the order of 1 Gbit/s. Services are expected in 2013.
As opposed to earlier generations, a 4G system does not support traditional circuit-switched telephony service, but all-Internet Protocol (IP) based communication such as IP telephony. As seen below, the spread spectrum radio technology used in 3G systems, is abandoned in all 4G candidate systems and replaced by OFDMA multi-carrier transmission and other frequency-domain equalization (FDE) schemes, making it possible to transfer very high bit rates despite extensive multi-path radio propagation (echoes). The peak bit rate is further improved by smart antenna arrays for multiple-input multiple-output (MIMO) communications.
The term “generation” used to name successive evolutions of radio networks in general is arbitrary. There are several interpretations of it, and no official definition has been made despite the large consensus behind ITU-R’s labels. From ITU-R’s point of view, 4G is equivalent to IMT-Advanced which has specific performance requirements as explained below. But according operators, a generation of network refers to the deployment of a new non-backward-compatible technology. This usually corresponds to a huge investment with its own depreciation period, marketing strategy (if any), and deployment phases. It can even be different among operators. From the end user’s point of view, only performance and cost makes sense. It is expected that the next generation of network performs better and cheaper than the previous generation, which is not that simple to state. Indeed, while a new generation of network arrives, the previous one can keep evolving to a point where it outperforms the first version of the new generation. In many countries, GSM, UMTS and LTE networks still coexist. It is thus much less ambiguous to use the name of the technology/standard, possibly followed by its version number, than a subjective arbitrary generation number which is destined to be challenged endlessly.
Beyond 4G research
A major issue in 4G systems is to make the high bit rates available in a larger portion of the cell, especially to users in an exposed position in between several base stations. In current research, this issue is addressed by macro-diversity techniques, also known as group cooperative relay, and also by Beam-Division Multiple Access (BDMA).
Pervasive networks are an amorphous and at present entirely hypothetical concept where the user can be simultaneously connected to several wireless access technologies and can seamlessly move between them (See vertical handoff, IEEE 802.21). These access technologies can be Wi-Fi, UMTS, EDGE, or any other future access technology. Included in this concept is also smart-radio (also known as cognitive radio) technology to efficiently manage spectrum use and transmission power as well as the use of mesh routing protocols to create a pervasive network.
5G (5th generation mobile networks or 5th generation wireless systems) is a term used in some research papers and projects to denote the next major phase of mobile telecommunications standards beyond the current 4G/IMT-Advanced standards. 5G does not describe any particular specification in any official document published by any telecommunication standardization body.
Although updated standards that define capabilities beyond those defined in the current 4G standards are under consideration, those new capabilities are still being grouped under the current 4G standards.
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Elvis peter is a technology enthusiastic , photographer, an android developer by profession, graduated from Dept of Information Technology, SOE CUSAT ( 2010 – 2014 batch ) and a proud owner of a lazy dog..