Wireless LAN Standards Since 1997, the Wireless LAN standards have been developed and maintained by the Institute of Electrical and Electronic Engineers (IEEE) 802.11 committee. In that time standards have been introduced for operation at 11Mbps (IEEE 802.11b) and 54Mbps (IEEE 802.11a and g). These existing standards use modulation techniques based on Direct Sequence Spread Spectrum (DSSS), Complementary Code Keying (CCK), or Orthogonal Frequency Division Multiplexing (OFDM) standards. The IEEE 802.11n standards group is currently defining the next generation of wireless LAN standards which will use Multiple Input Multiple Output (MIMO) modulation in addition to the existing modulation techniques. The draft v2.0 proposal for IEEE 802.11n was agreed in 2007 and the final standard should be ratified by early 2009. The evolution of these standards is shown in Table 1.

The IEEE 802.11n Standard

The IEEE 802.11n standard is currently at draft version 2.0. It is on track to be finally approved and ratified in 2009. In the meantime, working with the independent Wi-Fi Alliance organisation, vendors have developed interoperability standards and testing environments to make sure that the products built to the IEEE 802.11n draft v2.0 specification will work properly together. Consumers should look for the Wi-Fi N Draft Certified mark below to ensure products are compatible.

A Wireless LAN uses radio frequencies in the unlicensed public wavebands. The distance that the waves can travel is dependent on the quantity and composition of any intervening obstructions; this will determine the resulting network performance. In clear air, waves can travel up to 300-500 meters but intervening walls and metalwork will significantly reduce the range. Wireless LANs have invariably operated at slower speeds than their wired LAN counterparts. Whilst wired Ethernet can be operated over copper cabling at speeds of 100Mbps and even 1 or 10Gbps, wireless has been limited to a maximum transmit rate of 11Mbps (802.11b) or 54Mbps (802.11a/g) depending on which IEEE 802.11 standard is implemented. Real end-to-end throughput has been considerably less than this: typically 20-30Mbps in the case of 802.11a/g due to the overheads and constraints of frame sizes and the gaps required between successive frames in order for the radio antenna to synchronize and receive correctly.

The new IEEE 802.11n wireless technology provides significantly greater speed and range. More specifically IEEE 802.11n provides real-world speeds of 100Mbit/sec. to 140Mbit/sec. Range is harder to quantify because it&aposs affected by many variables, such as barriers that could block the signal. However, IEEE 802.11n equipment typically delivers more than twice the range of IEEE 802.11g equipment, at any given throughput speed. These improvements in speed and range provide enough bandwidth to surf the Internet, download MP3s, make Internet phone calls, share files, play network games, and stream high-definition videos, simultaneously at any distance or location in the home or office.

 

Wireless LAN Standards

The following certification programs provide certification marks and tests to ensure interoperability between different wireless vendor´s equipment.

Since 2000, the Wi-Fi Alliance has worked with its members to certify more than 3,500 Wi-Fi products. Through comprehensive testing, the Wi-Fi Alliance certification program ensures that wireless local area networking (WLAN) products from multiple manufacturers work with each other. Certification programs include basic connectivity, security, authentication, and Quality of Service (QoS).

Wi-Fi Protected Setup™ is an optional certification program from the Wi-Fi Alliance that is designed to ease the task of setting up and configuring security on wireless local area networks. Introduced by the Wi-Fi Alliance in early 2007, the program provides an industry-wide set of network setup solutions for homes and small office (SOHO) environments. Wi-Fi Protected Setup™ enables typical users who possess little understanding of traditional Wi-Fi configuration and security settings to automatically configure new wireless networks, add new devices and enable security. All current draft 11n products from SMC Networks support Wi-Fi Protected Setup™ - most of them are also certified.

 

Quality of Service

Even with faster 11n networking, delays can still occur if data is not prioritised. SMC's Intelligent Stream Handling Technology and Wi-Fi Multimedia™ WMM® automatically manage the flow of traffic, accurately identifying delay sensitive data and prioritising it. To prevent delays, time-sensitive applications such as online gaming and VoIP will automatically be given priority over other applications.

Wi-Fi Multimedia™ (WMM®) is a Wi-Fi Alliance® interoperability certification, that provides basic Quality of service (QoS) features to wireless networks. WMM® automatically prioritizes traffic according to four different traffic categories maintaining the priority of audio, video and voice applications. It is suitable for simple applications that require QoS, such as Voice over IP (VoIP) allowing voice packets to achieve priority across a network.

StreamEngine® technology delivers an enhanced online experience by employing powerful quality of service (QoS) mechanisms. "Intelligent Stream Handling" is a patent-pending algorithm which automatically manages the flow of traffic going to the Internet, without the need for user configuration. As a result, real-time interactive traffic, such as gaming, VoIP, instant messaging and video conferencing, are automatically given the appropriate priority when other users and applications use the network. In addition, Intelligent Stream Handling minimizes the impact of large-packet, lower-priority traffic on latency-sensitive traffic and eliminates delays caused by DSL or cable modem connections. StreamEngine® technology effectively eliminates the lag and breakup problem in online gaming and other voice/video applications. Read more

Trademark disclaimer:
The Wi-Fi CERTIFIED Logo is a certification mark of the Wi-Fi Alliance. The Wi-Fi Protected Setup Mark is a mark of the Wi-Fi Alliance. Ubicom, the Ubicom logo, StreamEngine, and the StreamEngine logo are trademarks of Ubicom, Inc.