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 Advances in Wireless Networking Standards1

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عدد الرسائل : 397
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تاريخ التسجيل : 25/05/2008

مُساهمةموضوع: Advances in Wireless Networking Standards1   الإثنين 26 مايو 2008, 2:13 pm

STANDARDIZATION IN IEEE 802
The IEEE Standards Association


The IEEE is a nonprofit transnational technical professional organization with over 350,000 individual members. IEEE supports many technical activities, including an active program in standardization through the IEEE Standards Association (IEEE-SA <http://standards.ieee.org>). IEEE standards are developed openly, with consensus in mind. Participation in their development and use is entirely voluntary.

However, history has shown that standards developed in an open forum can produce high quality, broadly accepted results capable of focusing companies and forging industries. Project development in the IEEE-SA is normally delegated to individual standard “sponsors,” one of the most important of which is IEEE 802. IEEE 802: The LAN MAN Standards Committee.


The IEEE 802 LAN MAN Standards Committee <http://ieee802.org>, which first met in 1980, develops and maintains standards at the physical layer (PHY) and medium access control sublayer (MAC), each of which fits under a common logical link control sublayer (LLC), as defined in IEEE Standard 802® [2].

Together, these make up the two lowest layers of the Open Systems Interconnection (OSI) seven-layer model for data networks. IEEE 802 holds weeklong plenary sessions three times a year; between each of these plenaries, most of its constituent Working Groups hold interim sessions.


Historically, 802 has been best known for IEEE Standard 802.3, informally known as Ethernet, which is so successful that it is virtually synonymous with wired LAN. Like all successful 802 standards, however, IEEE 802.3 continuously evolves, migrating from shared coaxial cabling to twisted-pair lines supporting data rates of 1 Gbit/s. The year 2002 saw the approval of IEEE Standard 802.3ae, which specifies 10 Gbit/s Ethernet over optical fiber and provides for linking Ethernet LANs to MANs and wide area networks (WANs). The current focus of 802.3 is the “Ethernet in the First Mile” project, which 4 intends to support high-speed access to businesses and homes, with minimal protocol conversion, over suitable twisted-pair copper cabling or passive optical networks. IEEE 802’s portfolio of active projects in the cabled realm grew in late 2000 with the approval of the IEEE 802.17 Working Group on Resilient Packet Rings.

While Ethernet has been its greatest success, IEEE 802 is now the home of a number of wireless network standardization projects that take advantage of its highly successful development system. Before
continuing with detailed discussion of the IEEE 802 wireless standards program, it will be useful to overview this process.


The IEEE 802 Standardization Process

The IEEE 802 process [3] is designed for quick development of standards with broad consensus. The demand for consensus helps to ensure that standards are technically refined and meet market needs. The essence of the process is a two-stage balloting system, each with multiple rounds, that seeks not only to confirm consensus but also to generate critical comment. It is sometimes said in IEEE 802 that the purpose of balloting is not to approve the draft standard but to improve it. Experience has shown that the
IEEE 802 process is extremely effective at engaging a wide variety of interested parties, fostering comments, and implementing constructive changes. As a result, 802 drafts are refined again and again.

By the time a draft is ready for approval, users have solid confidence in it. Yet, with careful attention and
the will of the developers, it is possible to drive the draft through the system within a reasonable time..


THE IEEE 802 WIRELESS STANDARDS PROGRAM

The IEEE 802 wireless standards program [4] comprises three working groups:
1. The IEEE 802.11 Working Group develops the IEEE 802.11standards for Wireless Local Area Networks (Wireless LAN)

2. The IEEE 802.15 Working Group develops the IEEE 802.15 standards for Wireless Personal Area
Networks (Wireless PAN)
3. The IEEE 802.16 Working Group on Broadband Wireless Access develops the IEEE 802.16 standards for Wireless Metropolitan Area Networks (WirelessMAN™).

In addition, two Technical Advisory Groups (TAGs) help coordinate activities:
1. The IEEE 802.18 Regulatory TAG
2. The IEEE 802.19 Coexistence TAG


The following sections summarize the status and technology of the projects in the IEEE 802 wireless standards program.

IEEE 802.11 Wireless Local Area Networks (Wireless LANs)

The IEEE 802.11 Working Group for Wireless Local Area Networks <http://ieee802.org/11> initiated
IEEE 802’s wireless effort, publishing its base standard in 1997. A revised 1999 edition was also published as international standard ISO/IEC 8802-11. The base standard includes three PHY
specifications, but one (infrared) has been little used. The other two obey spread-spectrum rules laid down for 2.4 GHz license-exempt use in the U.S. and later emulated in many other countries.
Two important PHY amendments (802.11a and 802.11b) were also published in 1999. IEEE 802.11b specifies a direct-sequence spread-spectrum (DSSS) system with a peak data rate of 11 Mbit/s. Lower
rates are available for poor links, with dynamic rate switching rules specified; typical range is on the order of 100 m. Since this mode is a backward-compatible extension of the original DSSS system, control information is transmitted at the common 1 Mbit/s rate.

This is one reason that actual throughput is less than ideal. The channel bandwidth is about 20 MHz, so that the typical North American and European frequency allocations (2.4–2.4835 GHz) provide for three non-overlapping channels (though overlapping channels are defined). A smaller Japanese allocation is noted in the standard. These devices are used in many countries, with varying spectrum allocations and power limits. IEEE Standard 802.11d provides for the specification of a “Country Information Element” that allows a station to identify the regulatory domain in which it is located and to configure its PHY accordingly.
Interoperability testing is critical to supplement standards. In the case of 802.11, the Wireless Ethernet Compatibility Alliance was created to develop interoperability tests and brand the interoperable products with the trademark Wi-Fi™. Wi-Fi has played a key role in the success of 802.11b, and nearly all commercial 802.11b products are Wi-Fi certified. The Wi-Fi procedures test some but not all 802.11b options; options that are not tested are rarely implemented in mass-market products.
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مُساهمةموضوع: رد: Advances in Wireless Networking Standards1   الثلاثاء 27 مايو 2008, 2:22 am

مشكور كثيرا على المساهمة القيمة
فقط الموضوع يحتاج لبعض التنسيق
lol! !!

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مُساهمةموضوع: رد: Advances in Wireless Networking Standards1   الأربعاء 28 مايو 2008, 8:28 am

كدة تمام يا باشمهندس منتصر
منتظرين جديدك


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مُساهمةموضوع: رد: Advances in Wireless Networking Standards1   الأربعاء 28 مايو 2008, 6:34 pm

الأخ المهندس مجاهد ,, مشكور على التعليق .
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Advances in Wireless Networking Standards1
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