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HOW WI-FI

CARA KERJA WI-FI

Wi-Fi is short for Wireless Fidelity, who has a sense of a set of standards used for Wireless Local Networks (Wireless Local Area Networks - WLANs) based on IEEE 802.11 specification. The latest standards of specifications 802.11a or b, such as 802.16 g, is currently in preparation, the latest specification will offer many improvements ranging from more extensive coverage to the transfer speed.

Wi-Fi was originally intended for the use of wireless devices and Local Area Network (LAN), but now more widely used to access the Internet. This allows anyone with a computer with a wireless card (wireless card) or personal digital assistant (PDA) to connect to the Internet by using a point
access (or known as hotspots) nearby.

Wi-Fi was designed based on the IEEE 802.11 specification. Today there are four variations of 802.11, namely:

* 802.11a
* 802.11b
* 802.11g
* 802.11n

Specifications b is the first Wi-Fi products. The variation of g and n is one product that has the most sales in 2005.

In many parts of the world, the frequencies used by Wi-Fi, users are not required to obtain permission from local regulators (eg, Federal Communications Commission in the U.S.). 802.11a uses a higher frequency and therefore narrower jangkaunya power, others the same.

Wi-Fi version of the most extensive in the U.S. market today (based in IEEE 802.11b / g) operates at 2400 MHz to 2483.50 MHz. With so allows operation in 11 channels (each 5 MHz), centered on the following frequencies:

* Channel 1 to 2.412 MHz;
* Channel 2 to 2.417 MHz;
* Channel 3 to 2.422 MHz;
* Channel 4 to 2.427 MHz;
* Channel 5 to 2.432 MHz;
* Channel 6 to 2.437 MHz;
* Channel 7 to 2.442 MHz;
* Channel 8 to 2.447 MHz;
* Channel 9 to 2.452 MHz;
* Channel 10 to 2.457 MHz;
* Channel 11 to 2.462 MHz

Operational Technically, Wi-Fi is one variant of communication and information technology that works on the network and the WLAN (wireless local area network). In other words, the Wi-Fi is a certification trademark given to manufacturers of telecommunications equipment (internet) working in WLAN networks and interoperates capacity already meets the required quality.

Technology-based Wi-Fi internet created and developed a group of U.S. engineers who worked at the Institute of Electrical and Electronis Engineers (IEEE) technical standards-based numbered devices 802.11b, 802.11a and 802.16. Wi-Fi devices are not only able to work in WLAN networks, but also on network Wireless Metropolitan Area Network (WMAN).

Because the device with the technical standard 802.11b WLAN devices intended for use in the 2.4 GHz frequency or frequencies, commonly called ISM (Industrial, Scientific and Medical). As for the technical standards 802.11a and 802.16 WMAN or destined for the device is also called Wi-Max, who works in the vicinity of 5 GHz frequency band.

High public interest - particularly among the Internet community - using Wi-Fi technology because at least two factors. First, the ease of access. This means that users in one area can access the Internet simultaneously without having to be bothered with cables.

Consequently, users who want to do surfing or browsing news and information on the Internet, simply bring the PDA (pocket digital assistance) or Wi-Fi enabled laptop into a place where there is access point or hotspot.

The proliferation of hotspots in places such - which was built by the telecom operators, Internet service providers and even individual people - triggered the second factor, namely due to construction costs which relatively cheap, or only around 300 dollars U.S..

Increasing the quantity of Internet users based Wi-Fi technology is increasingly implicated in various parts of the world, has encouraged Internet service providers (ISPs) to build hotspots in major cities of the world.

Some observers have even predicted in 2006, there will be 800,000 hotspots in European countries, 530,000 in the United States and one million in countries in Asia.

The overall amount of income derived by the United States and European countries of technology-based Internet business Wi-Fi until the end of 2003 was estimated at 5.4 trillion U.S. dollars, an increase of 33 billion U.S. dollars from the year 2002 (www.analysys.com).

In Indonesia alone, the use of Internet-based Wi-Fi already implicated in several major cities. In Jakarta, for example, the maniacs who are surfing the Internet while waiting for the plane took off at the airport waiting room, was not an alien.

The same phenomenon seen in many cafes - like a Starbucks Cafe and La Moda Cafe in Plaza Indonesia, the Coffee Club Senayan, and Cafe Coffee Bean in Cilandak Town Square - where the visitor can open the Internet to look at political news or gossip while sipping a cappuccino newest artist hot.

Today, business telephone-based VoIP (Voice over Internet Protocol) has also been using Wi-Fi technology, where calls are forwarded through the WLAN network. The application is named VoWi-FI (Voice over Wi-Fi).

Some time ago, the latest technical standards created by the IEEE has been able to support the operation of a streaming video service. Even the predictable, the future can be made cards (card)-based Wi-Fi technology that can be inserted into electronic equipment, ranging from digital cameras to video game consoles (ITU News 8 / 2003).

Based on the above explanation, can be concluded that the quantity of business and technology, Wi-Fi users tend to increase, and economically it has a positive impact on the national economy of a country, including Indonesia.

Nevertheless, the government should address the phenomenon wisely and carefully. The reason is, technologically frequency bands - both 2.4 GHz and 5 GHz - the container Wi-Fi technology operations are not free of limitations (Kompas, 5/2/2004).

Because the users in a new area can take advantage of wireless Internet system is optimally, when all the devices used in the area using a uniform transmit power and limited.

If the preconditions are not honored, will certainly take place harmful interference not only between devices of Internet users, but also with other telecommunications systems devices.

If interference continues - because users want more superior than other users, and therefore lack of understanding of the limitations of the technology - in the end will make the path a frequency of 2.4 GHz and 5 GHz could not be used optimally.

Another limitation of this second wireless frequency bands (particularly 2.4 GHz) is due also used for ISM (industrial, science and medical).

Consequently, the use of radio communications or other telecommunication device that works in the frequency band it should be ready to accept interference from ISM devices, as stated in S5.150 of the Radio Regulations.

In the recommendation ITU-R SM.1056, also informed the device characteristics of the ISM which basically aims to prevent occurrence of interference, both between devices with the ISM as well as telecommunications equipment sharing.

The same recommendation affirms that every member of the ITU-free establish administrative requirements and rules of law relating to mandatory restrictions power.

Recognizing the limitations and the impact that may arise from the use of both of the wireless frequency bands, various countries and impose regulations that limit the transmission power of the devices used.

Source

Translated by Google Translate
 
on February, Tuesday 15/2011 08:24 by Ahmad Maurits Radhiyya