What is 4G?4G (also known as Beyond 3G), an abbreviation for Fourth-Generation, is a term used to describe the next complete evolution in wireless communications. A 4G system will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to users on an "Anytime, Anywhere" basis, and at higher data rates than previous generations.

HistoryThe first analog cellular systems were based on IMTS (Improved Mobile Telephone Service) and developed in 1970. The systems were cellular because coverage areas were split into smaller areas or cells, each of which is served by a low power transmitter and receiver.

FEATURESSupportforinteractivemultimedia,voice,streamingvideo,Internet,andother broadband services: IPbasedmobilesystem Highspeed,highcapacity,andlowcostperbit Globalaccess,serviceportability,andscalablemobileservices Seamlessswitching,andavarietyofQualityofServicedrivenservices Betterschedulingandcalladmissioncontroltechniques Adhocandmultihopnetworks(thestrictdelayrequirementsofvoicemakemultihopnetworkserviceadifficultproblem) Betterspectralefficiency Seamlessnetworkofmultipleprotocolsandairinterfaces(since4GwillbeallIP,lookfor4Gsystemstobecompatiblewithallcommonnetworks technologies,including802.11,WCDMA,Bluetooth,andHyperLAN). Aninfrastructuretohandlepreexisting3Gsystemsalongwithotherwirelesstechnologies,some ofwhicharecurrentlyunderdevelopment.

Why 4G is required?At the first, we might have a question that why we even require 4G if 3G systems are working well. It is because of basically two reasons that one is substantial growth in overall number of subscribers and other is massive demand of new data services which can be either data, audio, image or video(interactive or non-interactive). Also the demand for increasing data rates leads to higher band width requirement. These factors cause the cellular industry to develop a common standard for a system that can work to overcome almost all the limitations imposed by the previous cellular technologies.

LimitationsAlthough the concept of 4Gcommunications shows much promise, there are still limitations that must be addressed. A major concern isinteroperability between thesignaling techniques that are planned for use in 4G. Cost is another factor that could hamper the progressof 4Gtechnology. The equipment required to implement the next-generation network are still very expensive. A Key challenge facing deployment of 4G technologies is how to make thenetwork architectures compatible with each other. This was one of the unmet goals of3G. As regards theoperating area, rural areas andmany building sin metropolitan areas are notbeing served well by existing wireless networks.

Implementation: We are bringing to the attention of professionals in telecommunications industry following issues and problems that must be analyzed and resolved: Lower Price Points Only Slightly Higher than Alternatives - The business visionaries should do some economic modeling before they start 4G hype on the same lines as 3G hype. They should understand that 4G data applications like streaming video must compete with very low cost wire line applications. The users would pay only a delta premium (not a multiple) for most wireless applications. More Coordination among Spectrum Regulators Around the World - Spectrum regulation bodies must get involved in guiding the researchers by indicating which frequency band might be used for 4G. FCC in USA must cooperate more actively with International bodies like ITU and perhaps modify its hands-off policy in guiding the industry. When public interest, national security interest and economic interest (inter-industry a la TV versus Telecommunications) are at stake, leadership must come from regulators. At appropriate time, industry builds its own self-regulation mechanisms. More Academic Research: Universities must spend more effort in solving fundamental problems in radio communications (especially multiband and wideband radios, intelligent antennas and signal processing. 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: Business development and technology executives should not bias their business models by using voice channels as economic determinant for data applications. Voice has a built-in demand limit - data applications do not.

Conclusion:As the history of mobile communications shows,attempts have been made to reduce a number oftechnologies to a single global standard. Projected 4G systems offer this promise of a standard that can be embraced worldwide through its key conceptof integration. Future wireless networks will need to support diverseIP multimedia applications to allow sharing ofresources among multiple users. There must be a low complexity ofimplementation and an efficient means of negotiation between the endusers and the wireless infrastructure. The fourthgeneration promises to fulfill the goal of PCC (personal computing andcommunication)a vision that affordably provides high data rates everywhere over a wireless network.

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