4G Wireless Systems
Published on Nov 23, 2015
Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency . The 4g wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB),and Millimeter wireless. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.
The high performance is achieved by the use of long term channel prediction, in both time and frequency, scheduling among users and smart antennas combined with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives the ability for world wide roaming to access cell anywhere.
4g wireless systems
Wireless mobile communications systems are uniquely identified by "generation designations. Introduced in the early 1980s, first generation (1G) systems were marked by analog frequency modulation and used primarily for voice communications. Second generation (2G) wireless communications systems, which made their appearance in the late 1980s, were also used mainly for voice transmission and reception
The wireless system in widespread use today goes by the name of 2.5G-an "in between " service that serves as a stepping stone to 3G. Whereby 2G communications is generally associated with Global System for Mobile (GSM) service, 2.5G is usually identified as being "fueled " by General Packet Radio Services (GPRS) along with GSM.
In 3G systems, making their appearance in late 2002 and in 2003, are designed for voice and paging services, as well as interactive media use such as teleconferencing, Internet access, and other services. The problem with 3G wireless systems is bandwidth-these systems provide only WAN coverage ranging from 144 kbps (for vehicle mobility applications) to 2 Mbps (for indoor static applications). Segue to 4G, the "next dimension " of wireless communication.
The 4g wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless and smart antenna. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.Frequency band is 2 ]8 GHz. it gives the ability for world wide roaming to access cell anywhere.
This new generation of wireless is intended to complement and replace the 3G systems. Accessing information anywhere, anytime, with a seamless connection to a wide range of information and services, and receiving a large volume of information, data, pictures, video, and so on, are the keys of the 4G infrastructures. The future 4G infrastructures will consist of a set of various networks using IP (Internet protocol) as a common protocol so that users are in control because they will be able to choose every application and environment. Based on the developing trends of mobile communication, 4G will have broader bandwidth, higher data rate, and smoother and quicker handoff and will focus on ensuring seamless service across a multitude of wireless systems and networks.
The key concept is integrating the 4G capabilities with all of the existing mobile technologies through advanced technologies. Application adaptability and being highly dynamic are the main features of 4G services of interest to users. These features mean services can be delivered and be available to the personal preference of different users and support the users' traffic, air interfaces, radio environment, and quality of service.
Connection with the network applications can be transferred into various forms and levels correctly and efficiently. The dominant methods of access to this pool of information will be the mobile telephone, PDA, and laptop to seamlessly access the voice communication, high-speed information services, and entertainment broadcast services.
The fourth generation will encompass all systems from various networks, public to private; operator-driven broadband networks to personal areas; and ad hoc networks. The 4G systems will interoperate with 2G and 3G systems, as well as with digital (broadband) broadcasting systems. In addition, 4G systems will be fully IP-based wireless Internet.
This all-encompassing integrated perspective shows the broad range of systems that the fourth generation intends to integrate, from satellite broadband to high altitude platform to cellular 3G and 3G systems to WLL (wireless local loop) and FWA (fixed wireless access) to WLAN (wireless local area network) and PAN (personal area network), all with IP as the integrating mechanism. With 4G, a range of new services and models will be available. These services and models need to be further examined for their interface with the design of 4G systems.
o Support for interactive multimedia, voice, streaming video, Internet, and other broadband services
o IP based mobile system
o High speed, high capacity, and low cost per bit
o Global access, service portability, and scalable mobile services
o Seamless switching, and a variety of Quality of Service driven services
o Better scheduling and call admission control techniques
o Ad hoc and multi hop networks (the strict delay requirements of voice make multi hop network service a difficult problem)
o Better spectral efficiency
o Seamless network of multiple protocols and air interfaces (since 4G will be all ]IP, look for 4G systems to be compatible with all common network technologies, including802.11, WCDMA, Blue tooth, and Hyper LAN).
o An infrastructure to handle pre existing 3G systems along with other wireless technologies, some of which are currently under development.
We do have are good reasons for 4G development and a variety of current and evolving technologies to make 4G a reality. Highlighting the primary drivers for 4G wireless systems are cost, speed, flexibility, and universal access. Both service providers and users want to reduce the cost of wireless systems and the cost of wireless services. The less expensive the cost of the system, the more people who will want to own it.
The high bandwidth requirements of upcoming streaming video necessitates a change in the business model the service providers use—from the dedicated channel per user model to one of a shared-use, as-packets-are-needed model. This will most likely be the model service provider’s use when 4G systems are commonplace (if not before).
Increased speed is a critical requirement for 4G communications systems. Data-rate increases of 10-50X over 3G systems will place streaming audio and video access into the hands of consumers who, with each wireless generation, demand a much richer set of wireless-system features. Power control will be critical since some services (such as streaming video) require much more power than do others (such as voice).
4G's flexibility will allow the integration of several different LAN and WAN technologies. This will let the user apply one 4G appliance, most likely a cell-phone/PDA hybrid, for many different tasks—telephony, Internet access, gaming, real-time information, and personal networking control, to name a few.
A 4G appliance would be as important in home-networking applications as it would as a device to communicate with family, friends, and co-workers.
Finally, a 4G wireless phone would give a user the capability of global roaming and access—the ability to use a cell phone anywhere worldwide. At this point, the 4G wireless system would truly go into a "one size fits all" category, having a feature set that meets the needs of just about everyone.
The mobile technology though reached only at 2.5G now, 4G offers us to provide with a very efficient and reliable wireless communication system for seamless roaming over various network including Internet, which uses IP network. The 4G systems will be implemented in the coming years, which are a miracle in the field of communication engineering technology.
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