27-11-2012, 02:36 PM
4G Second-generation (2G) mobile systems
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introduction:
4G refers to the fourth generation of cellular wireless standards. It is a successor to 3G and 2G families of standards. The nomenclature of the generations generally refers to a change in the fundamental nature of the service, non-backwards compatible transmission technology and new frequency bands. The 4G technology has promised to offer widespread, complete and invulnerable all-IP (Internet Protocol) based services example of such services are high quality multimedia streaming, enhanced gaming services, super fast broadband Internet access, IP telephony and etc. All these and many more facilities will soon be available to people all around the world by this groundbreaking technology. 100mbps would be the normal data rate for the users who are not stationary and moving at high speeds and 1gbps would be the maximum data rate when the user is indoor or at a fixed position.
EVOLUTION :
EVOLUTION First Generation (1G): 1G wireless mobile communication systems, was introduced in the early 1980s. 1G wireless was analog and supported the first generation of analog cell phones. They include a signaling protocol known as SS7 (Signaling System 7). Second Generation (2G): 2G systems, fielded in the late 1980s, were intended primarily for voice transmission and all about digital PCS. Third Generation (3G): 3G in wireless will be a deliberate migration to faster, data-centric wireless networks. The immediate goal is to raise transmission speeds from 125kbps to 2M bit/sec. Fourth Generation (4G): In reality, as of first half of 2002, 4G is a conceptual framework for or a discussion point to address future needs of a universal high speed wireless network that will interface with wire line backbone network seamlessly.
3G VS 4G :
3G VS 4G
CHALLENGES AND NEEDS :
CHALLENGES AND NEEDS Challenges in the Migration to 4G Second-generation (2G) mobile systems were very successful in the previous decade. Their success prompted the development of third generation (3G) mobile systems. While 2G systems such as GSM, IS-95, and cdmaOne were designed to carry speech and low-bit-rate data, 3G systems were designed to provide higher-data-rate services. During the evolution from 2G to 3G, a range of wireless systems, including GPRS, IMT-2000, Bluetooth, WLAN, and HiperLAN, have been developed. All these systems were designed independently, targeting different service types, data rates, and users. As all these systems have their own merits and shortcomings, there is no single system that is good enough to replace all the other technologies. Instead of putting efforts into developing new radio interfaces and technologies for 4G systems, which some researchers are doing, we believe establishing 4G . systems that integrate existing and newly developed wireless systems is a more feasible option.
Researchers are currently developing frameworks for future 4G networks. Different research programs, such as Mobile VCE, MIRAI, and DoCoMo, have their own visions on 4G features and implementations. Some key features (mainly from user's point of view) of 4G networks are stated as follows: :
Researchers are currently developing frameworks for future 4G networks. Different research programs, such as Mobile VCE, MIRAI, and DoCoMo, have their own visions on 4G features and implementations. Some key features (mainly from user's point of view) of 4G networks are stated as follows: "High usability: anytime, anywhere, and with any technology "Support for multimedia services at low transmission cost. "Personalization "Integrated services First, 4G networks are all IP based heterogeneous networks that allow users to use any system at any time and anywhere. Users carrying an integrated terminal can use a wide range of applications provided by multiple wireless networks. Second, 4G systems provide not only telecommunications services, but also data and multimedia services. To support multimedia services, high-data-rate services with good system reliability will be provided. At the same time, a low per-bit transmission cost will be maintained.
1.Third, personalized service will be provided by this new-generation network. It is expected that when 4G services are launched, users in widely different locations, occupations, and economic classes will use the services. In order to meet the demands of these diverse users, service providers should design personal and customized services for them. Finally, 4G systems also provide facilities for integrated services. Users can use multiple services from any service provider at the same time. Just imagine a 4G mobile user, Mary, who is looking for information on movies shown in nearby cinemas. Her mobile may simultaneously connect to different wireless systems. These wireless systems may include a Global Positioning System (GPS) (for tracking her current location), a wireless LAN (for receiving previews of the movies in nearby cinemas), and a code-division multiple access (CDMA) (for making a telephone call to one of the cinemas). In this example Mary is actually using multiple wireless services that differ in quality of service (QoS) levels, security policies, device settings, charging methods and applications. It will be a significant revolution if such highly integrated services are made possible in 4G mobile applications.
2.To migrate current systems to 4g with the features mentioned above, we have to face a number of challenges. In this article these challenges are highlighted and grouped into various research areas. An overview of the challenges in future heterogeneous systems will be provided. Each area of challenges will be examined in detail. The article is then concluded.
What is needed to Build 4G Networks of Future? :
What is needed to Build 4G Networks of Future? Lower Price Points Only Slightly Higher than Alternatives More Coordination Among Spectrum Regulators Around the World More Academic Research Standardization of wireless networks in terms of modulation techniques, switching schemes and roaming is an absolute necessity for 4G A Voice independent Business Justification Thinking Integration Across Different Network Topologies Non disruptive Implementation : 4G must allow us to move from 3G to 4G
4G NETWORK :
4G NETWORK
The 4G mobile networks could be systems: :
The 4G mobile networks could be systems: Horizontal communications between different access technology including cellular, cordless, wlan, short-range connectivity, and wired. A common platform to complement other services Connection through a common, flexible, seamless, IP-based core network. Advanced media access technology that connects the core network to different access technologies. Global roaming and interworking between different access technologies; both horizontal (intrasystem) and vertical (intersystem) handover. Seamless service negotiation including mobility, security, and QoS. 4G FEATURES
TRANSMISSION TECHNOLOGY :
TRANSMISSION TECHNOLOGY OFDM: OFDM is a digital modulation technology in which in one time symbol waveform, thousands of orthogonal waves are multiplexed. This is good for high bandwidth digital data transition. W-OFDM: W-OFDM enables data to be encoded on multiple high-speed radio frequencies concurrently. This allows for greater security, increased amounts of data being sent, and the industries most efficient use of bandwidth. W-OFDM enables the implementation of low power multipoint RF networks that minimize interference with adjacent networks. This enables independent channels to operate within the same band allowing multipoint networks and point-to-point backbone systems to be overlaid in the same frequency band. MC- CDMA : MC-CDMA is actually OFDM with a CDMA overlay. Similar to single-carrier CDMA systems, the users are multiplexed with orthogonal codes to distinguish users in (multi-carrier) MC-CDMA. However in MC-CDMA, each user can be allocated several codes, where the data is spread in time or frequency.
What Is The 4G Wireless Technology? :
We have seen and use the 2G (second generation) technology and 3G (third generation) technology. They are some old and current technologies for internet. When the speed and reliability of 2G was not enough, the 3G technology was developed. This 3G technology offered the world with new possibilities of using internet. With faster speed and greater reliable network than 2G, the 3G surely satisfied many users around the world. However, in this day and age, the demand for internet has become much greater. People are now seeking for more speed, good reliability and good network as the current facilities are not enough. This growing demand has become too much pressure on 3G and it is now unable to hold anymore stress. Therefore, a new generation technology, a successor of 3G technology is now being developed. It is a 4G or fourth generation wireless technology. It is being said that the 4G technology will greatly surpass the 3G in every way. Its introduction will offer a greater capacity, even faster speed and more reliable networks. The 4G wireless technology will also offer a greater coverage which even 3G was unable to do. It doesn’t matter whether you are traveling or you are in a far away location, the 4G will surely enable you to access internet from any device which support internet. This means that, not only you can access faster speed from home, but also you can enjoy the faster speed from your mobile phones. Currently, many mobile operators are in a process of changing their networks according to 4G technology so they can provide 4G service ASAP. Some operators will use WiMAX and some will be operating the LTE technology What Is The 4G Wireless Technology?