| INFORMATION |
| Published : |
Sep 28, 2009 |
| Length : |
7 |
| Type : |
White Paper |
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| Overview : |
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Wireless local area networks (WLANs) are quickly progressing beyond serving as "spot" solutions for data-centric, vertical applications such as retail barcode scanning and warehouse inventory picking. With the Ethernet-like throughput potential of the 802.11n Wi-Fi networks, WLANs are strong contenders for becoming businesses' mainstream, primary LAN access method.
In addition, because of the trend toward unified communications, collaborative network applications and IPTV, WLANs will soon be expected to regularly transport application traffic types that require predictable network throughput. Among this traffic is real-time voice and high-definition video. These multimedia transmissions can't tolerate flaky network connections that incur significant packet loss, delays and jitter. Such conditions can result in a phone call being dropped, an audio stream
being interrupted, or a video screen breaking up. |
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| Browse Related Categories : |
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802.11
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Mobile Computing
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RFID
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WLAN
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WiFi
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Wireless Infrastructure
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Wireless Service Providers
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Beamforming is a specialized method of radio-frequency (RF) transmission most often used in Wi-Fi access points (APs). APs that support beamforming focus the RF energy they radiate directly at a receiving Wi-Fi client device. The purpose is to improve signal reception at the client and, as a result, increase throughput.
Beamforming can do more than improve average throughput rates. It can be implemented in a way that delivers predictable throughput at a given range-performance that is sustained
even when the client device is in motion. Having both ample bandwidth and consistent bandwidth available at all times means users can enjoy a far more satisfying experience with Wi-Fi than has traditionally been possible. Stable connections are particularly important when users are engaged in voice and video sessions, which are far less tolerant of fluctuations in network performance than data applications.
Another valuable benefit of beamforming is its positive effect on "radio fog." By focusing transmissions toward receiving clients, beamforming avoids wasted energy and doesn't create unnecessary RF interference in other directions. Today, there are two popular methods of beamforming (see Figure 1): chip-based and antenna-based. And a third method will ultimately combine the two.
Chip-based transmit beamforming (often abbreviated as TxBF) is currently an option to the emerging IEEE 802.11n standard.
Within the chip-level implementation, there are three alternative methods: legacy, implicit, and explicit beamforming. These methods vary by how much, if any, feedback information from the client is necessary for them to work. Antenna-based beamforming is implemented in fi rmware that sits above 802.11's PHY and MAC layers. Also called smart antenna technology and required on the AP side only, it works with all 802.11 clients (a, b, g, n) and operates in a dynamic mode to adapt to changing environmental conditions and client locations.
Currently, implementations are based on individual vendors' intellectual property. Ruckus Wireless is one vendor that supports smart antenna-based beamforming with its patented BeamFlex technology, which is embedded in Ruckus APs.
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