Here After Forget FORMAT Your System!!

Here After No Need For Format Your System

Just Use the below Software Just one time back up.  After that If any problem Occur You can easily restore it in safe manner.

Symantec Norton Ghost description

Automatically Backup and Recovers everything on your computer:

 

Norton Ghost provides advanced backup and recovery for your computer. Protect your documents, financial records, presentations, photos, music, videos, historical documents, or any other kinds of data you keep on your computer by making a backup of your computer's entire hard disk. Or, limit your backup to include only those files and folders that mean the most to you.

You can schedule backups to capture your changes automatically as you work from day to day. Or start a backup manually at any time. You can also easily configure Norton Ghost to run a backup in response to specific events. For example, a backup can be started when a particular application is started, or when a specified amount of new data has been added to the drive.

When you experience a problem with your computer, you can restore a file, folder, or an entire drive, to return your computer to a previous, working state with the operating system, applications, and data files intact. Or if you accidently delete a personal file, get it back with a few simple steps.

Using easy-to-follow wizards, set up fast and reliable backups that run while you continue to work. Or schedule your backups to run after hours when you are no longer using your computer.

When disaster strikes, Norton Ghost helps you recover your computer from the effects of many common problems, including

· Virus attacks: Damage might be done before a virus is quarantined.

· Faulty software installations: Some software can negatively affect your computer's performance, slowing it     down to the point that opening programs or documents can require too much time. But once installed, uninstalling a product might not recover unintentional damage done during an install.

· Hard drive failure: Data can become corrupted on your system drive (typically C), making it impossible to start your operating system

· Files accidentally deleted or overwritten: Accidental deletion of files is common, but often costly.

· Corrupted files: Individual files and folders can become corrupted by viruses, or when a program used to modify them encounters an error

DOWNLOAD LINK : http://download1us.softpedia.com/dl/7d4c01649648c57b69eaaa02813724cb/488c98c5/100029350/software/system/backup/NortonGhost_Softpedia.exe

Audio <-> Video Convertor

• By use of this software you can convert all kind of format..
• One convertion software performs all kind of conversion..
• You can also convert your videos to your mobile format in very very easy manner..

SOFTWARE NAME : TOTAL VIDEO CONVERTER

Total Video Converter is a piece of extremely powerful and full-featured converter software that supports almost all video and audio formats. The software is designed to convert video for your mobile video player as 3gp, mp4, PSP, PS3, iPod, iPhone etc and also VCD or DVD player, XBOX360.

Main Features of Total Video Converter:

* Convert all kinds of videos to mobile videos or audios (mp4, 3gp, xvid, divx mpeg4 avi, amr audio) which are used by cell-phone, PDA, PSP, iPod, iPhone, Xbox360, PS3 etc.;

* Photos slide show combines multi-photos and musics with more than 300 photos fantasy transition effect;

* High compatibility and high efficiency for Importing RMVB or RM video/audio;

* Convert various videos to MPEG videos compatible with standard DVD/SVCD/VCD;

* Burn the converted videos to DVD/SVCD/VCD;

* Rip DVD to popular videos of all sorts;

* Extract audio from various of videos and convert which to all kinds of audios (mp3, ac3, ogg, wav, aac);

* RIP CD to audios of all sorts directly;

* Support using with command line;

* Combine several video and audio files to one video file;

* Demultiplex or extract video and audio;

* Multiplex video and audio to one file;

Download Link : http://www.effectmatrix.com/total-video-converter/tvc.exe

3G & 4G MOBILE SYSTEMS

4G Systems:

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.

As the second generation was a total replacement of the first generation networks and handsets; and the third generation was a total replacement of second generation networks and handsets; so too the fourth generation cannot be an incremental evolution of current 3G technologies, but rather the total replacement of the current 3G networks and handsets. The international telecommunications regulatory and standardization bodies are working for commercial deployment of 4G networks roughly in the 2012-2015 time scale. At that point it is predicted that even with current evolutions of third generation 3G networks, these will tend to be congested.

There is no formal definition for what 4G is; however, there are certain objectives that are projected for 4G. These objectives include: that 4G will be a fully IP-based integrated system. 4G will be capable of providing between 100 Mbit/s and 1 Gbit/s speeds both indoors and outdoors, with premium quality and high security. 

3G Systems :

3G technologies enable network operators to offer users a wider range of more advanced services while achieving greater network capacity through improved spectral efficiency. Services include wide-area wireless voice telephony and broadband wireless data, all in a mobile environment. Typically, they provide service at 5-10 Mb per second.

Unlike IEEE 802.11 networks, 3G networks are wide area cellular telephone networks which evolved to incorporate high-speed internet access and video telephony. IEEE 802.11 (common names Wi-Fi or WLAN) networks are short range, high-bandwidth networks primarily developed for data.

The first pre-commercial 3G network was launched by NTT DoCoMo in Japan branded FOMA, in May of 2001 on the W-CDMA technology. The first commercial launch of 3G was also by NTT DoCoMo in Japan on October 1, 2001. The second network to go commercially live was by SK Telecom in South Korea on the CDMA2000 1xEV-DO technology.

The first European pre-commercial network was at the Island of Man by Manx, the operator owned by the British Telecoms group, and the first commercial network in Europe was opened for business by Telenor in December 2001 with no commercial handsets and thus no paying customers. These were both on the W-CDMA technology.

The first commercial United States 3G network was by Monet, on CDMA2000 1x EV-DO technology, but this network provider later shut down operations. The first UMTS 3G network operator in the USA was Verizon.

The "first pre-commercial demonstration network" in the southern hemisphere was built in Adelaide, South Australia by m.Net Corporation in February 2002 using UMTS on 2100MHz. This was a demonstration network for the 2002 IT World Congress. The first "commercial" 3G network was launched by Hutchison Telecommunications branded as Three in April 2003. Australia's largest and fastest 3G UMTS/HSDPA network was launched by Telstra branded as "NextG(tm)" on the 850MHz band in October 2006, intended as a replacement of their cdmaOne network Australia wide.

In December 2007, 190 3G networks were operating in 40 countries and 154 HSDPA networks were operating in 71 countries, according to the Global mobile Suppliers Association. In Asia, Europe, Canada and the USA, telecommunication companies use W-CDMA technology with the support of around 100 terminal designs to operate 3G mobile networks.

In Europe, mass market commercial 3G services were introduced starting in March 2003 by Three (Part of the Hutchison Group) in the UK and Italy. The European Union Council suggested that the 3G operators should cover 80% of the European national populations by the end of 2005.

Roll-out of 3G networks was delayed in some countries by the enormous costs of additional spectrum licensing fees. See Telecoms crash. In many countries, 3G networks do not use the same radio frequencies as 2G, so mobile operators must build entirely new networks and license entirely new frequencies; an exception is the United States where carriers operate 3G service in the same frequencies as other services. The license fees in some European countries were particularly high, bolstered by government auctions of a limited number of licenses and sealed bid auctions, and initial excitement over 3G's potential. Other delays were due to the expenses of upgrading equipment for the new systems.

By June 2007 the 200 millionth 3G subscriber had been connected. Out of 3 billion mobile phone subscriptions worldwide this is only 6.7%. In the countries where 3G was launched first - Japan and South Korea - over half of all subscribers use 3G. In Europe the leading country is Italy with a third of its subscribers migrated to 3G. Other leading countries by 3G migration include UK, Austria, Australia and Singapore at the 20% migration level. A confusing statistic is counting CDMA 2000 1x RTT customers as if they were 3G customers. If using this oft-disputed definition, then the total 3G subscriber base would be 475 million at June 2007 and 15.8% of all subscribers worldwide.

Still several major countries such as Turkey, China etc have not awarded 3G licenses and customers await 3G services. China has been delaying its decisions on 3G for many years, partly hoping to have the Chinese 3G standard, TD-SCDMA, to mature for commercial production.

The first African use of 3G technology was a 3G videocall made in Johannesburg on the Vodacom network in November 2004. The first commercial launch of 3G in Africa was by EMTEL in Mauritius on the W-CDMA standard. In north African Morocco in late March 2006, a 3G service was provided by the new company Wana.

JAVA APPLET

JAVA APPLET INFORMATION

Following on from our first lesson where we created our ‘Hello World’ application we will see what else we can do with a simple Java application, then we will convert our ‘Hello World’ application to an applet and deploy it on a Web Page.

Lets start.

Cut 'n paste or type this program into your editor.

/* Lesson 2 */
/** This is our weight application */
class weight
{
public static void main(String[] arguments)
{
int lbs = 90;
System.out.println("Ally McBeals weight is now " +
lbs +
" lbs.");
}
}

Now what is new in this program?

We have declared a variable called lbs and it is an integer (a number to the laymen) and our output consists of concatenated strings and the lbs variable.

Compile the application typing:

javac weight.java from the DOS prompt if you are using Win 9x or the Command Prompt from Win NT.

When you have no compilation errors then run it using java weight  also from the DOS prompt if you are using Win 9x or the Command Prompt from Win NT.

You should see the output as

‘Ally McBeals weight is 90 lbs.’.

You may disagree with what I think she may weigh so what we are now going to do is pass some arguments to the application with what you think she may weigh.

Cut 'n paste or type this program into your editor.

/* Lesson 2 */
/** This is our weight2 application */
class weight2
{
public static void main(String[] arguments)
{
int lbs = 0;
if (arguments.length > 0)
lbs = Integer.parseInt (arguments[0]);
System.out.println("Ally McBeals weight " +
"is now " +
lbs + " lbs.");
}
}


Now what is new in this program.

We check if we have passed any arguments to the application by using the line ‘if (arguments.length > 0)’ and when then use ‘lbs = Integer.parseInt (arguments[0])’ to set the value of the variable lbs to the parameter that we used on the command line.

Compile the application using

javac weight2.java.

When you have no compilation errors then run it using

java weight2 77.

You should see the output:

‘Ally McBeals weight is 77 lbs.’.

Try it for yourself.



Now lets convert our weight application to a java applet.

/* Java 101 - Lesson 2 */
/** This is our weightapplet applet */
public class weightapplet extends java.applet.Applet
{
int lbs;
public void init()
{
lbs = 90;
}
public void paint(java.awt.Graphics g)
{
g.drawString("Ally McBeals weight is "
+ lbs + " lbs.",5,50);
}
}


Compile the applet using

javac weightapplet.java

Applets cannot be tested using the java interpreter tool. You have to put them on a web page and view them in one of two ways.

Use a web browsers such as the current versions of Mozila Fire Fox or Netscape Navigator or MS Internet  Explorer

Type the following line:
ENTER THE HTML APPLET CODE

appletviewer weightapplet.htm

and our weight estimate will appear in the viewer. We will discuss applets in more detail later...

Data Mining

THE DATA MINING PERFORMS AN IMPORTANT ROLE IN THE WORLD

Data Mining is the process of extracting knowledge hidden from large volumes of raw data.The knowledge must be new, not obvious, and one must be able to use it. 

Knowledge discovery differs from traditional information retrieval from databases.In traditional DBMS, database records are returned in response to a query; while in knowledge discovery, what is retrieved is not explicit in the database. Rather, it is implicit patterns. The Process of discovering such patterns is termed data mining. 

Data mining finds these patterns and relationships using data analysis tools and techniques to build models. There are two main kinds of models in data mining. One is predictive models, which use data with known results to develop a model that can be used to explicitly predict values. Aother is descriptive models, which describe patterns in existing data. All the models are abstract representations of reality, and can be guides to understanding business and suggest actions.

Following questions are probably be answered if information hidden among megabytes of data in your database can be found and utilized. Modeling the investigated system, discovering relations that connect variables in a database are the subject of data mining.

• What goods should be promoted to this customer?
• What is the probability that a certain customer will respond to a planned promotion?
• Can one predict the most profitable securities to buy/sell during the next trading session?
• Will this customer default on a loan or pay back on schedule?
• What medical diagnose should be assigned to this patient?
• How large the peak loads of a telephone or energy network are going to be?
• Why the facility suddenly starts to produce defective goods?

Desktop Sharing - Remote Control - Support

VERY USEFUL AND AMAZING DESKTOP SHARING

Team Viewer establishes connections to any PC all around the world within just a few seconds. You can remote control your partner's PC as if you were sitting right in front of it. Find out why more than 10.000.000 users trust Team Viewer!

*****Simple-Fast-Secure*****

SOFTWARE NAME : TEAM VIEWER

Download Link : http://www.teamviewer.com/download/TeamViewer_Setup.exe

Benifits Of the Software :

• One solution for everything

• Remote administration of unattended servers

• File transfer

• Remote support without installation

• Remote presentation of products, solutions and services

• Works behind firewalls

• Highest security standard

• Flexible use for a variety of applications

• No installation required

• High performance with international router network

Screenshot :

Top 10 Tips For Your iPhone 3G Gadget

For those of you who have got your very own iPhone 3G - and those just dreaming of getting your mitts on one - I choose 10 of my favourite tips to help improve your iPhone productivity.

If you’ve been one of the few fortunate enough to get hold of an iPhone 3G you’ll know not only about its style factor, but also all about its highly intuitive interface and ease of use.

However, precisely because it’s so easy to use, very few people are ever going to look at the manual, which means that they’ll be missing out on a few tips and tricks to help them get the most from the device. 

And, for many people it’ll be the first time they’ve used an iPhone. So to help get you started, we've put together a quick list of ten items to help you get the most from the much vaunted device.

1. Caps Lock feature

If you’ve ever tried to type in all caps on the iPhone you’ll know that it doesn’t appear to have a Caps Lock function, which can be quite frustrating when you want to really SHOUT in an email. 

Actually there is a Caps Lock feature, it’s just that you need to activate it manually by going to Settings>General>Keyboard (scroll down). Once enabled, you activate it by double tapping on the Caps button, which then turns blue. The only question then, is why the feature is off by default...

2. Double tapping keyboard for a full stop followed by space

This is a tip that is actually written in the Keyboard settings page described above, but unless you’ve been to that page you won’t have spotted it. A real time saver when you’re composing emails.

3. Choose suggestions by tapping space bar

As you type, you may have noticed words appearing underneath your chosen letters. These are suggestions, and you may be wondering how to select them – simply hit the spacebar. Cleverly, it also creates a space for you. Even more clever, though, is that if you choose a selection and then double tap the space bar to put in a full stop (see above), it will take out the space it’s just created. It’s like it’s thinking...

4. Hold down keys to get accented characters

If you’re the sort of person that likes to write words precisely as they should be, even when typing a text message, (as in, a pedant) then you’ll be pleased to find out that you can easily type accented characters on the iPhone – just hold down the keys (E, Y, U, I, O, A, S, L, Z, C, N) and the list of alternative pop up. Hold and down and slide across to choose the one you want. Touch.

5. Take a screenshot

It’s possibly a bit niche this one, not to say geeky, but with the 2.0 software you can now take screenshots on your iPhone. You simply hold down the Home button - that’s the actual physical button at the bottom - and then press the power button at the top. The display will flash and the image will appear in the camera roll. 

6. Double tap home button brings up Favourite contacts – or iPod

The problem with having no physical buttons means that it’s harder to make shortcuts. However, if you double press the home button, it will take you straight into your list of favourite contacts, enabling you to make calls quickly. And, if you double press the home button when the display is off it will bring up Play/Skip buttons so you can get to your music without even having to unlock the phone – perfect for listening to the IT PRO podcast.

7. Customise iPod bar

In the iPod application there are a number of options at the bottom – the iPod bar. However, you can customise these to your liking – simply select More, then choose Edit at the top left and select the icons you want, and drag them down to the bottom. 

8. Delete Applications or Move icons

If you want to remove an application from the iPhone - or just move an icon to a different location round the screen - you simply put your finger on any icon and hold it down, and after a few seconds every icon will start to shake with an ‘x’ appearing at the top left. You press the ‘x’ to remove it, or you press and drag the icons to your preferred locations on the screen, or even over to the next page of icons. Worth trying just to see the very cool shaking icon effect.

9. Add link to Home Screen

If you’ve got a web page that you like to visit regularly, then you can place an icon directly on the home screen so you can get straight to it. Press the ‘+’ symbol at the base of the Safari web browser and choose Add to Home Screen.

10. Correct mistakes with magnifying glass

This is actually a well-known keyboard feature, but just in case you don't know it, you should. If you make a mistake while typing, hold down your finger over the word in question and then a magnifying glass will appear enlarging the text. By rolling your finger gently, you can place the cursor precisely, enabling you to correct erroneous letters.

ZigBee Technology

Hi this Zigbee is a new technology and some one didn't hear about this. Please go through this article. You will gain some useful information

The low rate (LR) wireless personal access network (WPAN) (IEEE 802.15.4/LRWPAN) is intended to serve a set of industrial, residential, and medical applications with very low power consumption, low cost requirement, and relaxed needs for data rate and QoS .The low data rate enables the LR-WPAN to consume little power. ZigBee technology is a low data rate, low power consumption, low cost, wireless networking protocol targeted toward automation and remote control applications.

The IEEE 802.15.4 committee and ZigBee Alliance worked together and developed the technology commercially known as ZigBee. It is expected to provide low-cost and low-power connectivity for devices that need battery life as long as several months to several years but does not require data transfer rates as high as those enabled by Bluetooth. ZigBee can be implemented in mesh (peer- to-peer) networks larger than is possible with Bluetooth. ZigBee-compliant wireless devices are expected to transmit 10–75 minutes, depending on the RF environment and power output consumption required for a given application, and operate in the unlicensed RF worldwide (2.4 GHz global, 915 MHz America, or 868 MHz Europe) bands. The data rate is 250 kbps at 2.4 GHz, 40 kbps at 915 MHz, and 20 kbps at 868 MHz.

The IEEE 802.15.4 committee is focusing on the specifi cations of the lower two layers of the protocol (the physical and data link layers). On the other hand, ZigBee Alliance aims to provide the upper layers of the protocol stack (from the network to the application layer) for interoperable data interworking, security services, and a range of wireless home and building control solutions. ZigBee Alliance provides interoperability compliance testing, marketing of the standard, and advanced product engineering for the evolution of the standard. This will assure consumers to buy products from different manufacturers with confi dence that those products will work together.

ZigBee often uses a basic master-slave confi guration suited to static star networks of many infrequently used devices that talk via small data packets. It allows up to 254 nodes. Other network topologies such as peer-to-peer and cluster tree are also used. When ZigBee node is powered down, it can wake up and get a packet in around 15 msec.


ZigBee Components and Network Topologies

A ZigBee system consists of several components. The most basic is the device. A devicecan be a full-function device (FFD) or reduced-function device (RFD). A network includes at least one FFD, operating as the personal area network (PAN) coordinator.

The FFD can operate in three modes: a PAN coordinator, a coordinator, or a device. An RFD is intended for applications that are extremely simple and do not need to send large amounts of data. An FFD can talk to reduced-function or full-function devices, while an RFD can only talk to an FFD.

ZigBee supports three types of topologies: star topology, peer-to-peer topology, and cluster tree.

In the star topology, communication is established between devices and a single central controller, called the PAN coordinator. The PAN coordinator may be powered by mains while the devices will most likely be battery powered. Applicationsthat benefi t from this topology are home automation, personal computer (PC) peripherals, toys, and games.

After an FFD is activated for the fi rst time, it may establish its own network and become the PAN coordinator. Each star network chooses a PAN identifier, which is not currently used by any other network within the radio sphere of infl uence.This allows each star network to operate independently.

In the peer-to-peer topology, there is also one PAN coordinator. In contrast to star topology, any device can communicate with any other device as long as they are in range of one another. A peer-to-peer network can be ad hoc, self-organizing, and self-healing. Applications such as industrial control and monitoring, wireless sensor networks and asset and inventory tracking would benefi t from such a topology. It also allows multiple hops to route messages from any device to any other device in the network. It can provide reliability by multipath routing.

The cluster-tree topology is a special case of a peer-to-peer network in which most devices are full-function devices and an RFD may connect to a cluster-tree network as a leaf node at the end of a branch. Any of the full-function devices can act as a coordinator and provide synchronization services to other devices and coordinators. However, only one of these coordinators is the PAN coordinator.

The PAN coordinator forms the first cluster by establishing itself as the cluster head (CLH) with a cluster identifi er (CID) of zero, choosing an unused PAN identifi er, and broadcasting beacon frames to neighboring devices. A candidate device receiving a beacon frame may request to join the network at the cluster head. If the PAN coordinator permits the device to join, it will add this new device to its neighbor list. The newly joined device will add the cluster head as its parent in its neighbor list and begin transmitting periodic beacons such that other candidate devices may then join the network at that device. Once application or network requirements are met, the PAN coordinator may instruct a device to become the cluster head of a new cluster adjacent to the first one. The advantage of the clustered structure is the increased coverage at the cost of increased message latency.

Wireless Sensor Network Vs Ad Hoc Networking

In recent article I written about wireless sensor network. Here I written about the relation between Wireless Sensor Network and Ad Hoc Networking.

Wireless sensor network applications require wireless ad hoc networking techniques. Although many protocols and algorithms have been proposed for traditional wireless ad hoc networks, they are not well suited for the unique features and application requirements of wireless sensor networks. The differences between wireless sensor networks and traditional wireless ad hoc networks are listed here:

The number of sensor nodes in a wireless sensor network can be several orders of magnitude higher than the nodes in a wireless ad hoc network. In a wireless sensor network, sensor nodes are densely deployed. Sensor nodes are prone to failure.

The topology of a wireless sensor network changes very frequently. Sensor nodes mainly use broadcast communication paradigms whereas most traditional ad hoc networks are based on point-to-point communications.

Sensor nodes are limited in power, computational capabilities, and memory. Sensor nodes may not have global identifi cation because of the large amount of overhead and large number of sensors. Another factor that distinguishes wireless sensor networks from traditional mobile ad hoc networks (MANETs) is that the end goal is the detection/estimation of some event(s) of interest, and not just communication. To improve detection performance, it is often quite useful to fuse data from multiple sensors . Data fusion requires the transmission of data and control messages. This need may impose constraints on network architecture.

The large number of sensing nodes may congest the network with information. To solve this problem, some sensors, such as cluster heads, can aggregate the data, perform some computation (e.g., average, summation, highest value, etc.), and then broadcast the summarized new information.

Wireless Sensor Network

I think this article will be more useful who are interested in networking. Here I wrote about the wireless sensor networks

A wireless sensor network contains a large number of tiny sensor nodes that are densely deployed either inside the phenomenon to be sensed or very close to it. Sensor nodes consist of sensing, data processing, and communicating components. The position of sensor nodes need not be engineered or predetermined.

Wired sensor networks have been around for decades, with an array of gauges measuring temperature, fluid levels, humidity, and other attributes on pipelines, pumps, generators, and manufacturing lines. Many of these run as separately wired networks, sometimes linked to a computer but often to a control panel that fl ashes lights or sounds an alarm when a temperature rises too high or a machine vibrates too much. Also wired in are actuators, which let the control panel slow down a pump or start a fan in response to the sensor data.

Now advances in silicon radio chips, coupled with cleverly designed routing algorithms and network software are promising to eliminate those wires and their installation and maintenance costs. Mesh network topologies will let these wireless networks route around nodes that fail or whose radio signal is degraded by interferencefrom heavy equipment.

A gateway will create a two-way link with legacy control systems, hosts, wired local area networks (WLANs), or the Internet Wireless sensor networks can use several different wireless technologies, including IEEE 802.11 WLANs, Bluetooth, and radio frequency identifi cation (RFID). But at present most of the applications are of low-power radios having a range of about 30 to 200 feet and data rates of up to around 300 kbps. IEEE 802.15.4 is the approved low-rate standard for a simple, short-range wireless network whose radio components could run several years on a single battery.

4G

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 first was the move from 1981 analog (1G) to digital (2G) transmission in 1992. This was followed, in 2002, by 3G multi-media support, spread spectrum transmission and at least 200 kbit/s, soon expected to be followed by 4G, which refers to all-IP packet-switched networks, mobile ultra-broadband (gigabit speed) access and multi-carrier transmission. Pre-4G technologies such as mobile WiMAX and first-release 3G Long term evolution (LTE) have been available on the market since 2006 and 2009^.

Overview

A 4G system is expected to provide a comprehensive and secure all-IP based solution where facilities such as IP telephony, ultra-broadband Internet access, gaming services, and streamed multimedia may be provided to users.

This article uses 4G to refer to IMT-Advanced (International Mobile Telecommunications Advanced), as defined by ITU-R..

An IMT-Advanced cellular system must have target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the ITU requirements. Scalable bandwidths up to at least 40 MHz should be provided.

In all suggestions for 4G, the CDMA spread spectrum radio technology used in 3G systems and IS-95 is abandoned and replaced by frequency-domain equalization schemes, for example multi-carrier transmission such as OFDMA. This is combined with MIMO (i.e., multiple antennas(Multiple In Multiple Out)), dynamic channel allocation and channel-dependent scheduling.

Predecessors of 4G

First-release LTE

Telia-branded Samsung LTE modem

The pre-4G technology 3GPP Long Term Evolution (LTE) is often branded "4G", but the first LTE release does not fully comply with the IMT-Advanced requirements. LTE has a theoretical net bit rate capacity of up to 100 Mbit/s in the downlink and 50 Mbit/s in the uplink if a 20 MHz channel is used — and more if Multiple-input multiple-output (MIMO), i.e. antenna arrays, are used.

The world's first publicly available LTE-service was opened in the two Scandinavian capitals Stockholm (Ericsson system) and Oslo (a Huawei system) on the 14 December 2009, and branded 4G. The user terminals were manufactured by Samsung. The two largest major mobile carriers in the United States and several worldwide carriers have announced plans to convert their networks to LTE beginning in 2011.

The physical radio interface was at an early stage named High Speed OFDM Packet Access (HSOPA), now named Evolved UMTS Terrestrial Radio Access (E-UTRA).

LTE Advanced (Long-term-evolution Advanced) is a candidate for IMT-Advanced standard, formally submitted by the 3GPP organization to ITU-T in the fall 2009, and expected to be released in 2012. The target of 3GPP LTE Advanced is to reach and surpass the ITU requirements. LTE Advanced should be compatible with first release LTE equipment, and should share frequency bands with first release LTE.

WiMAX and Mobile WiMAX

The Mobile WiMAX (IEEE 802.16e-2005) mobile wireless broadband access (MWBA) standard is sometimes branded 4G, and offers peak data rates of 128 Mbit/s downlink and 56 Mbit/s uplink over 20 MHz wide channels. The IEEE 802.16m evolution of 802.16e is under development, with the objective to fulfill the IMT-Advanced criteria of 1 Gbit/s for stationary reception and 100 Mbit/s for mobile reception. The world's first commercial mobile WiMAX service was opened by KT in Seoul, South Korea on 30 June 2006.

Sprint Nextel has begun using WiMAX, branded as a "4G" network.

UMB (formerly EV-DO Rev. C)

Main article: Ultra Mobile Broadband

UMB (Ultra Mobile Broadband) was the brand name for a discontinued 4G project within the 3GPP2 standardization group to improve the CDMA2000 mobile phone standard for next generation applications and requirements. In November 2008, Qualcomm, UMB's lead sponsor, announced it was ending development of the technology, favouring LTE instead. The objective was to achieve data speeds over 275 Mbit/s downstream and over 75 Mbit/s upstream.

Flash-OFDM

At an early stage the Flash-OFDM system was expected to be further developed into a 4G standard.

Objective and approach

Objectives

4G is being developed to accommodate the quality of service (QoS) and rate requirements set by further development of existing 3G applications like mobile broadband access, Multimedia Messaging Service (MMS), video chat, mobile TV, but also new services like HDTV. 4G may allow roaming with wireless local area networks, and may interact with digital video broadcasting systems.

The 4G working group has defined the following as objectives of the 4G wireless communication standard:

• Flexible channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz.
• A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the station, and 1 Gbit/s while client and station are in relatively fixed positions as defined by the ITU-R,
• A data rate of at least 100 Mbit/s between any two points in the world, Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth)
• System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage.
• Smooth handoff across heterogeneous networks,
• Seamless connectivity and global roaming across multiple networks,
• High quality of service for next generation multimedia support (real time audio, high speed data, HDTV video content, mobile TV, etc.)
• Interoperability with existing wireless standards, and
• An all IP, packet switched network.
• Femtocells (home nodes connected to fixed Internet broadband infrastructure)

Approaches

Consideration points

• Coverage, radio environment, spectrum, services, business models and deployment types, users.

Principal technologies

• Physical layer transmission techniques
• MIMO: To attain ultra high spectral efficiency by means of spatial processing including multi-antenna and multi-user MIMO
• Frequency-domain-equalization, for example Multi-carrier modulation (OFDM) or single-carrier frequency-domain-equalization (SC-FDE) in the downlink: To exploit the frequency selective channel property without complex equalization.
• Frequency-domain statistical multiplexing, for example (OFDMA) or (Single-carrier FDMA) (SC-FDMA, a.k.a. Linearly precoded OFDMA, LP-OFDMA) in the uplink: Variable bit rate by assigning different sub-channels to different users based on the channel conditions
• Turbo principle error-correcting codes: To minimize the required SNR at the reception side
• Channel-dependent scheduling: To utilize the time-varying channel.
• Link adaptation: Adaptive modulation and error-correcting codes
• Relaying, including fixed relay networks (FRNs), and the cooperative relaying concept, known as multi-mode protocol

4G features

The 4G system was originally envisioned by the Defense Advanced Research Projects Agency (DARPA). The DARPA selected the distributed architecture, end-to-end Internet protocol (IP), and believed at an early stage in peer-to-peer networking in which every mobile device would be both a transceiver and a router for other devices in the network eliminating the spoke-and-hub weakness of 2G and 3G cellular systems. However, the first LTE USB dongles do not support any other radio interface. Although legacy systems are in place to adopt existing users, the infrastructure for 4G will be only packet-based (all-IP). Some proposals suggest having an open Internet platform. At an early stage, technologies considered to be 4G were: Flash-OFDM, the 802.16e mobile version of WiMax (also known as WiBro in South Korea), HC-SDMA (see iBurst), and LTE.

Components

Access schemes

As the wireless standards evolved, the access techniques used also exhibited increase in efficiency, capacity and scalability. The first generation wireless standards used plain TDMA and FDMA. In the wireless channels, TDMA proved to be less efficient in handling the high data rate channels as it requires large guard periods to alleviate the multipath impact. Similarly, FDMA consumed more bandwidth for guard to avoid inter carrier interference. So in second generation systems, one set of standard used the combination of FDMA and TDMA and the other set introduced an access scheme called CDMA. Usage of CDMA increased the system capacity, but as a theoretical drawback placed a soft limit on it rather than the hard limit (i.e. a CDMA network setup does not inherently reject new clients when it approaches its limits, resulting in a denial of service to all clients when the network overloads; though this outcome is avoided in practical implementations by admission control of circuit switched or fixed bitrate communication services). Data rate is also increased as this access scheme (providing the network is not reaching its capacity) is efficient enough to handle the multipath channel. This enabled the third generation systems, such as IS-2000, UMTS, HSXPA, 1xEV-DO, TD-CDMA and TD-SCDMA, to use CDMA as the access scheme. However, the issue with CDMA is that it suffers from poor spectral flexibility and computationally intensive time-domain equalization (high number of multiplications per second) for wideband channels.

Recently, new access schemes like Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Interleaved FDMA and Multi-carrier CDMA (MC-CDMA) are gaining more importance for the next generation systems. These are based on efficient FFT algorithms and frequency domain equalization, resulting in a lower number of multiplications per second. They also make it possible to control the bandwidth and form the spectrum in a flexible way. However, they require advanced dynamic channel allocation and traffic adaptive scheduling.

WiMax is using OFDMA in the downlink and in the uplink. For the next generation UMTS, OFDMA is used for the downlink. By contrast, IFDMA is being considered for the uplink since OFDMA contributes more to the PAPR related issues and results in nonlinear operation of amplifiers. IFDMA provides less power fluctuation and thus avoids amplifier issues. Similarly, MC-CDMA is in the proposal for the IEEE 802.20 standard. These access schemes offer the same efficiencies as older technologies like CDMA. Apart from this, scalability and higher data rates can be achieved.

The other important advantage of the above mentioned access techniques is that they require less complexity for equalization at the receiver. This is an added advantage especially in the MIMO environments since the spatial multiplexing transmission of MIMO systems inherently requires high complexity equalization at the receiver.

In addition to improvements in these multiplexing systems, improved modulation techniques are being used. Whereas earlier standards largely used Phase-shift keying, more efficient systems such as 64QAM are being proposed for use with the 3GPP Long Term Evolution standards.

IPv6 support

Main articles: Network layer, Internet protocol, and IPv6

Unlike 3G, which is based on two parallel infrastructures consisting of circuit switched and packet switched network nodes respectively, 4G will be based on packet switching only. This will require low-latency data transmission.

By the time that 4G is deployed, the process of IPv4 address exhaustion is expected to be in its final stages. Therefore, in the context of 4G, IPv6 support is essential in order to support a large number of wireless-enabled devices. By increasing the number of IP addresses, IPv6 removes the need for Network Address Translation (NAT), a method of sharing a limited number of addresses among a larger group of devices, although NAT will still be required to communicate with devices that are on existing IPv4 networks.

As of June 2009, Verizon has posted specifications that require any 4G devices on its network to support IPv6.

Advanced Antenna Systems

Main articles: MIMO and MU-MIMO

The performance of radio communications depends on an antenna system, termed smart or intelligent antenna. Recently, multiple antenna technologies are emerging to achieve the goal of 4G systems such as high rate, high reliability, and long range communications. In the early 1990s, to cater for the growing data rate needs of data communication, many transmission schemes were proposed. One technology, spatial multiplexing, gained importance for its bandwidth conservation and power efficiency. Spatial multiplexing involves deploying multiple antennas at the transmitter and at the receiver. Independent streams can then be transmitted simultaneously from all the antennas. This technology, called MIMO (as a branch of intelligent antenna), multiplies the base data rate by (the smaller of) the number of transmit antennas or the number of receive antennas. Apart from this, the reliability in transmitting high speed data in the fading channel can be improved by using more antennas at the transmitter or at the receiver. This is called transmit or receive diversity. Both transmit/receive diversity and transmit spatial multiplexing are categorized into the space-time coding techniques, which does not necessarily require the channel knowledge at the transmitter. The other category is closed-loop multiple antenna technologies, which require channel knowledge at the transmitter.

Software-Defined Radio (SDR)

SDR is one form of open wireless architecture (OWA). Since 4G is a collection of wireless standards, the final form of a 4G device will constitute various standards. This can be efficiently realized using SDR technology, which is categorized to the area of the radio convergence.

History of 4G and pre-4G technologies

• In 2002, the strategic vision for 4G — which ITU designated as IMT-Advanced — was laid out.
• In 2005, OFDMA transmission technology is chosen as candidate for the HSOPA downlink, later renamed 3GPP Long Term Evolution (LTE) air interface E-UTRA.
• In November 2005, KT demonstrated mobile WiMAX service in Busan, South Korea.
• In June 2006, KT started the world's first commercial mobile WiMAX service in Seoul, South Korea.
• In mid-2006, Sprint Nextel announced that it would invest about US$5 billion in a WiMAX technology buildout over the next few years ($5.4 billion in real terms). Since that time Sprint has faced many setbacks, that have resulted in steep quarterly losses. On May 7, 2008, Sprint, Imagine, Google, Intel, Comcast, Bright House, and Time Warner announced a pooling of an average of 120 MHz of spectrum; Sprint merged its Xohm WiMAX division with Clearwire to form a company which will take the name Clear.
• In February 2007, the Japanese company NTT DoCoMo tested a 4G communication system prototype with 4x4 MIMO called VSF-OFCDM at 100 Mbit/s while moving, and 1 Gbit/s while stationary. NTT DoCoMo completed a trial in which they reached a maximum packet transmission rate of approximately 5 Gbit/s in the downlink with 12x12 MIMO using a 100 MHz frequency bandwidth while moving at 10 km/h, and is planning on releasing the first commercial network in 2010.
• In September 2007, NTT Docomo demonstrated e-UTRA data rates of 200 Mbit/s with power consumption below 100 mW during the test.
• In January 2008, a U.S. Federal Communications Commission (FCC) spectrum auction for the 700 MHz former analog TV frequencies began. As a result, the biggest share of the spectrum went to Verizon Wireless and the next biggest to AT&T Both of these companies have stated their intention of supporting LTE.
• In January 2008, EU commissioner Viviane Reding suggested re-allocation of 500–800 MHz spectrum for wireless communication, including WiMAX.
• February 15, 2008 - Skyworks Solutions released a front-end module for e-UTRAN.
• In April 2008, LG and Nortel demonstrated e-UTRA data rates of 50 Mbit/s while travelling at 110 km/h.
• In 2008, ITU-R established the detailed performance requirements of IMT-Advanced, by issuing a Circular Letter calling for candidate Radio Access Technologies (RATs) for IMT-Advanced.
• April 2008, just after receiving the circular letter, the 3GPP organized a workshop on IMT-Advanced where it was decided that LTE-Advanced, an evolution of current LTE standard, will meet or even exceed IMT-Advanced requirements following the ITU-R agenda.
• On 3 March 2009, Lithuanian's LRTC announcing the first operational "4G" mobile WiMAX network in Baltic states.
• In December 2009, Sprint began advertising "4G" service in selected cities in the United States, despite average download speeds of only 3-6Mbps with peak speeds of 10Mbps (not available in all markets).
• On December 14, 2009, the first commercial LTE deployment was in the Scandinavian capitals Stockholm and Oslo by the Swedish-Finnish network operator TeliaSonera and its Norwegian brandname NetCom (Norway). TeliaSonera branded the network "4G". The modem devices on offer were manufactured by Samsung (dongle GT-B3710), and the network infrastructure created by Huawei (in Oslo) and Ericsson (in Stockholm). TeliaSonera plans to roll out nationwide LTE across Sweden, Norway and Finland. TeliaSonera used spectral bandwidth of 10 MHz, and single-in-single-out, which should provide physical layer net bitrates of up to 50 Mbit/s downlink and 25 Mbit/s in the uplink. Introductory tests showed a TCP throughput of 42.8 Mbit/s downlink and 5.3 Mbit/s uplink in Stockholm.
• On 25 February 2010, Estonia's EMT opened LTE "4G" network working in test regime.
• On 5 June 2010, Sprint Nextel released the first 4G Smartphone, the HTC Evo 4G.
• On July 2010, Uzbekistan's MTS deployed LTE in Tashkent.
• On 25 August 2010, Latvia's LMT opened LTE "4G" network working in test regime 50% of territory.

Deployment plans

In May 2005, Digiweb, an Irish fixed and wireless broadband company, announced that they have received a mobile communications license from the Irish Telecoms regulator, ComReg. This service will be issued the mobile code 088 in Ireland and will be used for the provision of 4G Mobile communications. Digiweb launched a mobile broadband network using FLASH-OFDM technology at 872 MHz.

On September 20, 2007, Verizon Wireless announced that it plans a joint effort with the Vodafone Group to transition its networks to the 4G standard LTE. On December 9, 2008, Verizon Wireless announced that they intend to build and begin to roll out an LTE network by the end of 2009. Since then, Verizon Wireless has said that they will start their rollout by the end of 2010.

On July 7, 2008, South Korea announced plans to spend 60 billion won, or US$58,000,000, on developing 4G and even 5G technologies, with the goal of having the highest mobile phone market share by 2012, and the hope of an international standard.

Telus and Bell Canada, the major Canadian cdmaOne and EV-DO carriers, have announced that they will be cooperating towards building a fourth generation (4G) LTE wireless broadband network in Canada. As a transitional measure, they are implementing 3G UMTS that went live in November 2009.

Sprint offers a 3G/4G connection plan, currently available in select cities in the United States. It delivers rates up to 10 Mbit/s.

In the United Kingdom, Telefónica O2 is to use Slough as a guinea pig in testing the 4G network and has called upon Huawei to install LTE technology in six masts across the town to allow people to talk to each other via HD video conferencing and play PlayStation games while on the move.

Verizon Wireless has announced that it plans to augment its CDMA2000-based EV-DO 3G network in the United States with LTE. AT&T, along with Verizon Wireless has chosen to migrate toward LTE from 2G/GSM and 3G/HSPA by 2011.

The U.S. FCC is exploring the possibility of deployment and operation of a nationwide 4G public safety network which would allow first responders to seamlessly communicate between agencies and across geographies, regardless of devices. In June 2010 the FCC released a comprehensive white paper which indicates that the 10 MHz of dedicated spectrum currently allocated from the 700 MHz spectrum for public safety will provide adequate capacity and performance necessary for normal communications as well as serious emergency situations.

TeliaSonera started deploying LTE (branded "4G") in Stockholm and Oslo November 2009 (as seen above), and in several Swedish, Norwegian, and Finnish cities during 2010. In June 2010, Swedish television companies used 4G to broadcast live television from the Swedish Crown Princess' Royal Wedding.

Beyond 4G research

Main article: 5G

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 basestations. In current research, this issue is addressed by macro-diversity techniques, also known as group cooperative relay, and also by beam-division multiple access.

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.

4G wireless standards

In September 2009, the technology proposals have been submitted to ITU-R as 4G candidates. Basically all proposals are based on two technologies:

• LTE Advanced standardized by the 3GPP
• 802.16m standardized by the IEEE (i.e. WiMAX)

First set of 3GPP requirements on LTE Advanced has been approved in June 2008. LTE Advanced will be standardized in 2010 as part of the Release 10 of the 3GPP specification. LTE Advanced will be fully built on the existing LTE specification Release 10 and not be defined as a new specification series. A summary of the technologies that have been studied as the basis for LTE Advanced is summarized in a technical report.

Application of 4G

Virtual presence — 4G will provide user services at all times, even if the user
is off-site.

Virtual navigation — 4G will provide users with virtual navigation through
which a user can access a database of streets, buildings, etc., of a large city.
This requires high speed transmission.

Tele-medicine — 4G will support the remote health monitoring of patients
via video conference assistance for a doctor at anytime and anywhere.
Tele-geo-processing applications — 4G will combine geographical information
systems (GIS) and global positioning systems (GPS) in which a user will
get location querying.

Education — 4G will provide a good opportunity to people anywhere in the
world to continue their education on-line in a cost-effective manner.

3G Systems

The International Telecommunication Union (ITU) began studies on the globalization of personal communications in 1986 and identifi ed the long-term spectrum requirements for the future third-generation (3G) mobile wireless telecommunications systems. In 1992, the ITU identifi ed 230 MHz of spectrum in the 2 GHz band to implement the IMT-2000 system on a worldwide basis for satellite andterrestrial components. The aim of IMT-2000 is to provide universal coverage enabling terminals to have seamless roaming across multiple networks. The ITU accepted the overall standardization responsibility of IMT-2000 to defi ne radio interfaces that are applicable in different radio environments including indoor, outdoor, terrestrial, and satellites.

Access and global roaming for a wide range of services. Standards bodies in Europe, Japan, and North America are trying to achieve harmony on key and interrelated issues including radio interfaces, system evolution and backward compatibility, user’s migration and global roaming, and phased introduction of mobile services and capabilities to support terminal mobility. Universal Mobile Telecommunication System (UMTS) studies were carried out by ETSI in parallel with IMT-2000 to harmonize its efforts with ITU. In Japan and North America, standardization efforts for 3G were carried out by the Association of Radio Industries Business (ARIB) and the TIA committee TR45, respectively. Two partnership projects, 3GPP and 3GPP2, are involved in harmonizing 3G efforts in Europe, Japan, and North America.

In Europe, 3G systems are intended to support a substantially wider and enhanced range of services compared to the 2G (GSM) system. These enhancements include multimedia services, access to the Internet, high rate data, and so on. The enhanced services impose additional requirements on the fi xed network functions to support mobility. These requirements are achieved through an evolution path to capitalize on the investments for the 2G system in Europe, Japan, and North America.

In North America, the 3G wireless telecommunication system, cdma2000 was proposed to ITU to meet most of the IMT requirements in the indoor office, indoor to outdoor pedestrian, and vehicular environment. In addition, the cdma2000 satisfi es the requirements for 3G evolution of 2G TIA/EIA 95 family of standards (cdmaOne).

In Japan, evolution of the GSM platform is planned for the IMT (3G) core network due to its fl exibility and widespread use around the world. Smooth migration from GSM to IMT-2000 is possible. The service area of the 3G system overlays with the existing 2G (PDC) system. The 3G system connects and interworks with 2G systems through an interworking function (IWF). An IMT-2000-PDCdual mode terminal as well as the IMT-2000 single mode terminal are deployed.

EDGE

EDGE

EDGE makes use of the existing GSM infrastructure in a highly effi cient manner. Radio network planning will not be greatly affected since it will be possible to reuse many existing BTS sites. GPRS packet switching nodes will be unaffected, because they function independently of the user bit rates, and any modifi cations to the switching nodes will be limited to software upgrades. There is also a smooth evolution path defi ned for terminals to ensure that EDGE-capable terminals will be small and competitively priced.

EDGE-capable channels will be equally suitable for standard GSM services, and no special EDGE, GPRS, and GSM services will be needed. From an operator viewpoint this allows a seamless introduction of new EDGE services — perhaps starting with the deployment of EDGE in the service hot spots and gradually expanding coverage as demand dictates. The roll-out of EDGE-capable BSS hardware can become part of the ordinary expansion and capacity enhancement of the network. The wideband data capabilities offered by EDGE allows a step-by-step evolution to IMT-2000, probably through a staged deployment of the new 3G air interface on the existing core GSM network. Keeping GSM as the core network for the provision of 3G wireless services has additional commercial benefi ts. It protects the investment of existing operators; it helps to ensure the widest possible customer base from the outset; and it fosters supplier competition through the continuous evolution of systems.

GSM operators who win licenses in new 2 GHz bands will be able to introduce IMT-2000 wideband coverage in areas where early demand is likely to be greatest. Dual-mode EDGE/IMT-2000 mobile terminals will allow full roaming and handoff from one system to the other, with mapping of services between the two systems. EDGE will contribute to the commercial success of the 3G system in the vital early phases by ensuring that IMT-2000 subscribers will be able to enjoy roaming and interworking globally.

Building on an existing GSM infrastructure will be relatively fast and inexpensive, compared to establishing a total 3G system. The intermediate move to GPRS and later to EDGE will make the transition to 3G easier. While GPRS and EDGE require new functionality in the GSM network, with new types of connections to external packet data networks they are essentially extensions of GSM. Moving to a GSM/IMT-2000 core network is likewise a further extension of this network.


SEVICES OFFERED BY EDGE

PS Services. The GPRS architecture provides IP connectivity from the mobile station to an external fi xed IP network. For each service, a QoS profi le is defi ned. The QoS parameters include priority, reliability, delay, and maximum and mean bit rate. A specifi ed combination of these parameters defi nes a service, and different services can be selected to suit the needs of different applications. CS Services. The current GSM standard supports both transparent (T) and nontransparent (NT) services. Eight transparent services are defi ned, offering constant bit rates in the range of 9.6 to 64 kbps.

A nontransparent service uses RLP to ensure virtually error-free data delivery. For this case, there are eight services offering maximum user bit rates from 4.8 to 57.6 kbps. The actual user bit rate may vary according to channel quality and the resulting rate of transmission.

The introduction of EDGE implies no change of service defi nitions. The bit rates are the same, but the way services are realized in terms of channel coding is different. For example, a 57.6 kbps nontransparent service can be realized with coding scheme ECSD TCS-1 (telephone control channel-1) and two time slots, while the same service requires four time slots with standard GSM using coding scheme TCH/F14.4. Thus, EDGE CS transmission makes the high bit rate services available with fewer time slots, which is advantageous from a terminal implementation perspective. Additionally, since each user needs fewer time slots, more users can be accepted which increases the capacity of the system.

Asymmetric Services Due to Terminal Implementation. ETSI has standardized two mobile classes: one that requires only GMSK transmission in the uplinkand 8-PSK in the downlink and one that requires 8-PSK in both links. For the first class, the uplink bit rate is limited to that of GSM/GPRS, while the EDGE bit rate is still provided in the downlink. Since most services are expected to require higher bit rates in the downlink than in the uplink, this is a way of providing attractive services with a low complexity mobile station. Similarly, the number of time slots available in the uplink and downlink need not be the same. However, transparent services will be symmetrical.

WLAN

Hi visitors this is a article about the Wireless Local Area Networks and its Equipment.

WLAN

With the success of wired local area networks (LANs), the local computing market is moving toward wireless LAN (WLAN) with the same speed of current wired LAN. WLANs are fl exible data communication systems that can be used for applications in which mobility is required. In the indoor business environment, although mobility is not an absolute requirement, WLANs provide more fl exibility than that achieved by the wired LAN. WLANs are designed to operate in industrial, scientifi c, and medical (ISM) radio bands and unlicensed-national information infrastructure (U-NII) bands. In the United States, the Federal Communications Commission (FCC) regulates radio transmissions; however, the FCC does not require the end-user to buy a license to use the ISM or U-NII bands. Currently, WLANs can provide data rates up to 11 Mbps, but the industry is making a move toward high-speed WLANs. Manufacturers are developing WLANs to provide data rates up to 54 Mbps or higher. High speed makes WLANs a promising technology for the future data communications market.

The IEEE 802.11 committee is responsible for WLAN standards. WLANs include IEEE 802.11a (WiFi 5), IEEE 802.11b (WiFi), IEEE 802.11g and IEEE 802.11n The deployment of WLANs can provide connectivity in homes, factories, and hot-spots. The IEEE 802.16 group is responsible for wireless metropolitan area network (WMAN) standards. This body is concerned with fixed broadband wireless access systems, also known as “last mile” access networks. In this chapter, we focus on different types of WLANs and introduce IEEE 802.16 standards including WiMAX (high speed WLAN).


WLAN EQUIPMENTS

There are three main links that form the basis of the wireless network. These are:

LAN adapter: Wireless adapters are made in the same basic form as their wired counterparts: PCMCIA, Card bus, PCI, and USB. They also serve the same function, enabling end-users to access the network. In a wired LAN, adapters provide an interface between the network operating system and the wire. In a WLAN, they provide the interface between the network operating system and an antenna to create a transparent connection to the network.

Access point (AP): The AP is the wireless equivalent of an LAN hub. It receives, buffers, and transmits data between the WLAN and the wired network, supporting a group of wireless user devices. An AP is typically connected with the backbone network through a standard Ethernet cable, and communicates with wireless devices by means of an antenna. The AP or antenna connected to it is generally mounted on a high wall or on the ceiling. Like cells in a cellular network, multiple APs can support handoff from one AP to another as the user moves from area to area. APs have a range from 20 to 500 meters. A single AP can support between 15 to 250 users, depending on technology, confi guration, and use. It is relatively easy to scale a WLAN by adding more APs to reduce network congestion and enlarge the coverage area. Large networks requiring multiple APs deploy them to create overlapping cells for constant connectivity to the network. A wireless AP can monitor movement of a client across its domain and permit or deny specifi c traffi c or clients from communicating through it.

Outdoor LAN bridges: Outdoor LAN bridges are used to connect LANs in different buildings. When the cost of buying a fi ber optic cable between buildings is considered, particularly if there are barriers such as highways or bodies of water in the way, a WLAN can be an economical alternative. An outdoor bridge can provide a less expensive alternative to recurring leasedline charges. WLAN bridge products support fairly high data rates and ranges of several miles with the use of line-of-sight directional antennas. Some APs can also be used as a bridge between buildings of relatively close proximity.

WAP - Wireless Application Protocol

Hi this is a small introduction to wap services which we are using in most of the mobiles WAP has become the defacto global industry standard for providing data to wireless hand-held mobile devicesWAP takes a client server approach and incorporates a relatively simple microbrowser into the mobile phone, requiring only limited resources on mobile phones. WAP puts the intelligence in the WAP Gateways while adding just a microbrowser to the mobile phones themselves. Microbrowser-based services and applications reside temporarily on servers, not permanently in phones. The WAP is aimed at turning mass-market phones into a network-based smart phone. The philosophy behind WAP’s approach is to use as few resources as possible on the hand-held device and compensate for the constraints of the device by enriching the functionality of the network.

WAP specifi es a thin-client microbrowser using a new standard called wireless markup language (WML) that is optimized for wireless hand-held mobile devices. WML is a stripped down version of HTML.

WAP specifi es a proxy server that acts as a gateway between the wireless network and the wireline Internet, providing protocol translation and optimizing data transfer for the wireless handset. WAP also specifi es a computer-telephony integration application programming interface (API), called wireless telephony application interface (WTAI), between data and voice. This enables applications to take full advantage of the fact that this wireless mobile device is most often a phone and a mobile user’s constant companion. On-board memory on a WAP phone can be used for off-line content, enhanced address books, bookmarks, and text input methods.

The importance of WAP can be found in the fact that it provides an evolutionary path for application developers and network operators to offer their services on different network types, bearers, and terminal capabilities. The design of the WAP standard separates the application elements from the bearer being used. This helps in the migration of some applications from short message service (SMS) or circuit-switched (CS) data to general packet radio service (GPRS), for
example. WAP 1.0 was optimized for early WAP-phones.

The wireless application protocol cascading style sheet (WAP CSS) is the mobile version of a cascading style sheet. It is a subset of CSS2 (the cascading style sheet language of the world wide web) plus some WAP specifi c extensions. CSS2 features and properties that are not useful for mobile Internet applications are not included in WAP CSS. WAP CSS is the companion of XHTML Mobile Profile (XHTML MP). Both of them are defi ned in the WAP 2.0 specifi cation, which was created by the WAP forum. XHTML MP is a subset of XHTML, which is the combination of HTML and XML. There are many WAP 2.0-enabled cell phones on the market currently.

DATABASE CONCEPTS

What's a database ?

A database is a collection of data organized in a particular way. Databases can be of many types such as Flat File Databases, Relational Databases, Distributed Databases etc.

What's SQL ?
SQL is the short form of srtuctured query language.

In 1971, IBM researchers created a simple non-procedural language called Structured English Query Language. or SEQUEL. This was based on Dr. Edgar F. (Ted) Codd's design of a relational model for data storage where he described a universal programming language for accessing databases.

In the late 80's ANSI and ISO (these are two organizations dealing with standards for a wide variety of things) came out with a standardized version called Structured Query Language or SQL. SQL is prounced as 'Sequel'. There have been several versions of SQL and the latest one is SQL-99. Though SQL-92 is the current universally adopted standard.

SQL is the language used to query all databases. It's simple to learn and appears to do very little but is the heart of a successful database application. Understanding SQL and using it efficiently is highly imperative in designing an efficient database application. The better your understanding of SQL the more versatile you'll be in getting information out of databases.

What's an RDBMS ?

This concept was first described around 1970 by Dr. Edgar F. Codd in an IBM research publication called "System R4 Relational".

A relational database uses the concept of linked two-dimensional tables which comprise of rows and columns. A user can draw relationships between multiple tables and present the output as a table again. A user of a relational database need not understand the representation of data in order to retrieve it. Relational programming is non-procedural.

Whatis a DBMS ?

MySQL and mSQL are database management systems or DBMS. These software packages are used to manipulate a database. All DBMSs use their own implementation of SQL. It may be a subset or a superset of the instructions provided by SQL 92. MySQL, due to it's simplicity uses a subset of SQL 92 (also known as SQL2).

What's Database Normalization ?

Normalization is the process where a database is designed in a way that removes redundancies, and increases the clarity in organizing data in a database.

In easy English, it means take similar stuff out of a collection of data and place them into tables. Keep doing this for each new table recursively and you'll have a Normalized database. From this resultant database you should be able to recreate the data into it's original state if there is a need to do so.

The important thing here is to know when to Normalize and when to be practical. That will come with experience. For now, read on...

Normalization of a database helps in modifying the design at later times and helps in being prepared if a change is required in the database design. Normalization raises the efficiency of the datatabase in terms of management, data storage and scalability.

RFID- Radio Frequency Identification

RFID is one of the most popular method of short range wireless communications.

Radio frequency identifi cation (RFID) is an automatic identifi cation method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is an object that can be attached to or incorporated into a product, animal, or person for the purpose of identifi cation using radio waves. Chip-based RFID tags contain silicon chips and antennas. Passive tags require no internal power source, whereas active tags require a power source. RFID is also called dedicated short range communication (DSRC).

In a typical RFID system, individual objects are equipped with a small, inexpensive tag. The tag contains a transponder with a digital memory chip that is given a unique electronic product code. The transponder emits messages with an identifi cation number that is retrieved from a database and acted upon accordingly. The writable memory is used to transmit information among RFID readers in different locations The interrogator, an antenna packaged with a transceiver and decoder, emits a signal activating the RFID tag so it can read and write data to it. When an RFID tag passes through the electromagnetic zone, it detects the reader’s activation signal. The reader decodes the data encoded in the tag’s integrated circuit (silicon chip) and the data is passed to the host computer. The application software on the host processes the data, and may perform various fi ltering operations to reduce the numerous often redundant reads of the same tag to a smaller and more useful data set.

The following are the RFID components and their characteristics:
Tags
Active (with watch-sized battery)
Passive (without battery)
Semi-active (with battery)
Size (varies from less than 1 square inch to many square inches)
Dependent on power and frequency (13.56 MHz, 433 MHz, 900 MHz,
2.4 GHz with power from 1 mW to 1 W)
Memory can be read only, write one and read many with 1 byte to
512 Kilo-bytes storage.
Reader
Receive data
Validate data
Send data to tag
Middleware
Host data management software applications

The following are the key features of RFID:

No line-of-sight. RFID tags do not need to be visible to read or write. Robust. Because RFID systems do not need to be visible, they can be encased within rugged material protecting them from the environment in which they are being used. This means they can be used in harsh fl uid and chemical environments and rough handling situations. Read speed. Tags can be read from signifi cant distances and can also be read very quickly — for example, on a conveyor.

Reading multiple items. A number of tagged items can be read at the same time within an RF fi eld. This cannot be done easily with visual identify errors. Security. Because tags can be enclosed, they are much more diffi cult to tamper with. A number of tag types now also come programmed with a unique identifi er (serial identifi cation) which is guaranteed to be unique throughout the world.

Programmability. Many tags are read/write capable, rather than read only. This means that information can be written to the tag, perhaps to show that the item being tagged has gone through a particular process, or that its condition or status has changed somehow.

Applications of RFID

RFID has various applications due to its liberal cost and also have more advantages.

RFID systems can be used just about anywhere, from clothing tags to missiles to pet tags to food — anywhere that a unique identifi cation system is needed. The tag can carry information as simple as a pet owner’s name and address or the cleaning instructions on a sweater to as complex as instructions on how to assemble a car. Some auto manufacturers use RFID systems to move cars through an assembly line. At each successive stage of production, the RFID tag tells the computers what the next step of the automated assembly is. The following are
some of the applications of RFID systems:

Automotive. Auto makers have added security and convenience to automobiles by using RFID technology for anti-theft immobilizers and passiveentry systems.

Animal tracking. Ranchers and livestock producers use RFID technology to meet export regulations and optimize livestock value. Wild animals are tracked in ecological studies, and many pets who are tagged are returned to their owners.

Assets tracking. Hospitals and pharmacies meet tough product accountability legislation with RFID; libraries limit theft and keep books in circulation more effi ciently; and sports and entertainment entrepreneurs fi nd that “smart tickets” are their ticket to a better bottom line and happier customers.

Contactless commerce. Blue-chip companies such as American Express, Exxon Mobile, and MasterCard use innovative form factors enabled by RFID technology to strengthen brand loyalty and boost revenue per customer.

Supply chain. Wal-Mart, Target, Best Buy, and other retailers have discovered that RFID technology can keep inventories at the optimal level, reduce outof- stock losses, limit shoplifting, and speed customers through check-out lines.

RFID tags are often envisioned as a replacement for bar codes, having a number of important advantages over bar code technology. One of the key differences between RFID and bar code technology is RFID eliminates the need of line-of-sight reading that bar coding depends on. Also, RFID scanning can be done at greater distances than bar code scanning. High frequency RFID systems(850–950 MHz, 2.4–2.5 GHz) offer transmission ranges more than 90 feet. Bar codes are fi xed at the time of printing and can be rendered useless by defacement or smudging. Bar codes can be spoofed or easily defeated by any malicious individual having a laser printer at their disposal.