•4G is the short name for fourth-generation wireless, the stage ofmobile communications that will enable things like IP-based voice,data, gaming services and high quality streamed multimedia onportable devices with cable modem-like transmission speeds.4G wireless: One View
ABOUT 4G WIRELESS SYSTEM 4G is the fourth generation wireless networkcommunications technology Standard. This new generation of wireless is intended to complementand replace the 3G systems. The 4G infrastructures will consist of a set of variousnetworks using IP (Internet protocol) as a common protocol. Application adaptability and being highly dynamic are themain features of 4G services. 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 wirelessInternet.
1.Technologies That comprise 4G 4G is based entirely on packet switched networks.Standards such as 3G and Bluetooth will be incorporated in to the 4G standards.2.Need for 4GFirstly 3G’s maximum data transfer rate of 384 Kbps to2mbps is much slower than 20 to 100 Mbps of 4G.With its use of existing technologies and communicationstandards, 4G present a comparably inexpensive standard.4G will utilize most of the existing wireless communicationinfrastructure.3.Specifications of 4G4G can provide a 10 times increase in data transfer over 3G.This speed can be achieved through Orthogonal FrequencyDivision Multiplexing (OFDM).OFDM can not only transfer data at speed of more than 100 Mbps, butit can also eliminate interference that impairs high speed signals.
4.The potential applications of 4G 4G will provide for a vast number of presentlynon-existent applications for mobile devices.4G devices will differ from present day mobiledevices in that there will be navigation menus.4G will provide a seamless network for userswho travel and require uninterrupted voice/dataconnections.
COMPARING KEY PARAMETERS OF 4G WITH 3G3G 4GMajor Requirement DrivingArchitecturePredominantly voice driven-data was always add onConverged data and voice overIPNetwork architecture Wide area cell based Hybrid –integration of wirelessLAN and wide areaSpeed 384 Kbps to 2 Mbps 20 to 100 Mbps in mobile modeFrequency Band 1800-2400 MHz Higher frequency bands (2-8GHz)Switching Design Basis Circuit and Packet All digital with packetized voiceAccess Technologies W-CDMA, OFDM and MC-CDMA (MultiCarrier CDMA)Component Design Optimized antenna design,multi-band adaptersSmarter Antennas, softwaremultilane and wideband radiosIP A number of air linkprotocols, including IP 5.0All IP (IP6.0)
4G NETWORK ARCHITECTURE The number of access networksin public, private business andhome areas is increasing. Service providers will needaccess to specific networkcharacteristics to be able toenhance their services, and mayhave certain requirements suchas minimum delay guarantees. Another aspect is that the userneeds to control the usage of theavailable networks, especiallywhen this usage comes with aprice.
Business model of 4G NetworkThe current model assumes there are relationships between theend user, the service provider, and the network operator.In the 4G , the number of access networks and the number ofnetwork operators will increase rapidly.Both the end user and the service provider do not want to bebothered with the peculiarities of these networks.This asks for a service centric approach where the enduser, the service provider and network operator are looselycoupled through a Service Support role.Two main responsibilities of Service Support are Serviceaggregation and Network integration .
Service aggregation (SA)enables service provisioningto end users. whereasnetwork integration (NI) ensures thatthis can be realized regardlessof the network the end user isconnected to. The end user benefits frombeing able to access his/hersubscribed services anywhereand anytime.
ISSUES REGARDING IMPLEMENTING 4GWIRELESS NETWORKS•Access•Handoff•Location Coordination•Resource coordination to add new users•Support for quality of service•Wireless securities and authentication•Network failure and backup•Pricing and billing
WIRELESS TECHNOLOGIESUSED IN 4GA. OFDM (ORTHOGONAL FREQUENCY DIVISIONMULTEPLEXING)B. UWB (ULTRA WIDE BAND)C. MILLIMETER WIRELESSD. SMART ANTENNASE. LONG TERM POWER PREDICTIONF. SCHEDULING AMONG USERSG. ADAPTIVE MODULATION AND POWER CONTROL
Orthogonal Frequency DivisionMultiplexing Orthogonal Frequency Division Multiplexing (OFDM) provides clearadvantages for physical layer performance, but also a framework forimproving layer 2 performance by proposing an additional degree of free-domain. In ODFM, it is possible to exploit the time domain, the space domain, thefrequency domain and even the code domain to optimize radio channelusage. It ensures very robust transmission in multi-path environments with reducedreceiver complexity. OFDM also provides a frequency diversity gain, improving the physical layerperformance . It is also compatible with other enhancement Technologies, such as smartantennas and MIMO. OFDM modulation can also be employed as a multiple access technology(Orthogonal Frequency Division Multiple Access; OFDMA). In this case, each OFDM symbol can transmit information to/from severalusers using a different set of sub carriers (sub channels).
Smart Antennas Switched Beam Antennas Adaptive Array Antennas Smart antennas can : Optimize available power Increase base station rangeand coverage Reuse available spectrum Increase bandwidth Lengthen battery life ofwireless devices
Millimeter Wireless In a 4G system, millimeterwireless would constitute only oneof several frequency bands, withthe 5GHz band most likelydominant.
Scheduling among Users To optimize the system throughput, underspecified QoS requirements and delayconstraints, scheduling will be used ondifferent levels:a)Among sectors:b) Among users:
Adaptive modulation and powercontrol In a fading environment and for a highly loaded system therewill almost exist users with good channel conditions. The modulation format for the scheduled user is selectedaccording to the predicted signal to noise and interferenceratio. By using sufficiently small time-frequency bins the channelcan be made approximately constant within bins. For every timeslot, the time-frequency bins in the gridrepresent separate channels. For such channels the optimum rate and power allocation formaximizing the throughput can be calculated under a totalaverage power constraint. The optimum strategy is to let one user, the one with bestchannel, transmit in each of the parallel channels.
Software Defined Radio A software defined radio is one that can be configured to anyradio or frequency standard through the use of software. A software defined radio in the context of 4G would be able towork on different broadband networks and would be able totransfer to another network seamlessly while traveling outsideof the user’s home network. A software defined radio’s best advantage is its great flexibilityto be programmed for emerging wireless standards. It can bedynamically updated with new software without any changesin hardware and infrastructure. software could just download interface automatically . This is the job of the packet layer, which will split the data intosmall “packets.”
Packet Layer The packet layer is a layer of abstraction thatseparates the data being transmitted from the waythat it is being transmitted. The Internet relies on packets to move files,pictures, video, and other information over thesame hardware. Without a packet layer, there would need to be aseparate connection on each computer for eachtype of information and a separate network withseparate routing equipment to move thatinformation around.
pAcKETAdvatages of packet layer:-*Packets are a proven method to transfer information.*A predictable algorithm does not split packets .*The data in packets can be encrypted using conventional dataencryption methods.*There is no simple way to reconstruct data from packetswithout being the intended recipient.*More Flexible*More Reliable
ADVANTAGES OF 4G Support for interactive multimedia, voice, streaming video, Internet, and otherbroadband services. IP based mobile system. High speed, high capacity, and low cost-per-bit Global access, service portability, and scalable mobile servicesSeamless switching, and a variety of Quality of Service-driven services Better scheduling and call-admission-control techniques Ad-hoc and multi-hop networks Better spectral efficiency Seamless network of multiple protocols and air interfaces.
DISADVANTAGES Expensive. Battery uses are more. Hard to implement Need complicated hardware.
APPLICATIONS OF 4G• 4G Car• 4G and public safety• Sensors in public vehicle• Cameras in traffic light• First responder route selection• Traffic control during disasters
FUTURE There are some good reasons for 4G development and avariety of current and evolving technologies to make 4G areality. Both service providers and users want to reduce the cost ofwireless systems and the cost of wireless services. Lesser the expensive of the system, the more people whowill want to own it. 4Gs flexibility will allow the integration of several differentLAN and WAN technologies. Finally, the 4G wireless system would truly go into a "one sizefits all" category, having a feature set that meets the needs ofjust about everyone.
CONCLUSION All totally the best way to help all users is to use 4Gas the next wireless system and in totally it is safetyand secure for public, this the need that demands thesolution. Today’s wired society is going wireless and if it hasproblem, 4G is answer.