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a group of radios operating in ad-hoc mode, with some kind of routing applied. Many mesh routing protocols (such as B.A.T.M.A.N. or OLSR) may be applied to any physical network, including WiFi devices in Master/Managed nodes, or even other physical network types (such as Ethernet). Dynamic mesh.
Most commercial wireless devices (mobile phones, television, radio, etc.) use licensed radio frequencies. Large organizations pay licensing fees for the right to use those radio frequencies. WiFi uses unlicensed spectrum. License fees are not usually required to operate WiFi equipment. The Industrial, Scientific and Medical (ISM)
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- Are All Radios the Same?
- A Primer on Antennas
- Signal Gain
- Polarization
- Telling Antennas Apart
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Radios everywhere but there are relatively few radio chipset vendors on the market today; these include manufacturers such as Intel, Broadcom, Atheros, and Marvell. Most Wi-Fi equipment vendors use the same radio chipsets and have access to all the same capabilities. So where is the difference? Where’s the value-add that sets one AP apart from the ...
An antenna provides three things to a radio: gain, direction and polarization. Gain is the amount of increase in energy that an antenna adds to the RF signal. Direction refers to the shape of the transmission, which describes the coverage area. Polarization is the orientation of the electric field (transmission) from the antenna. These three charac...
Gain is a measurement of the degree of direction within an antenna’s radiation pattern. An antenna with a low signal gain transmits with about the same power in all directions. Conversely, a high-gain antenna typically transmits in a particular direction. Signal gain focuses the RF emission and improve sig-nal quality, but it doesn’t add power. Thi...
Polarization is the orientation of the signal as it leaves the antenna. All antennas have some kind of polarization. There are many different kinds of polarization, however most Wi-Fi antennas are linearly polarized and will have either vertical or horizontal polarization. (See Figure 4) Polarization is important because it describes the orientatio...
One of the most important skills a WLAN engineer (or anyone who works with Wi-Fi networks) can have is being able to distinguish antenna differences. Not all antenna types work or perform the same way. The easiest way to compare antennas is through the characteristics just discussed: signal gain, di-rection and polarization. Another key piece of in...
This kind of issue is fairly easy to verify — just try moving a laptop around. Turn it 90° and run a throughput or signal strength test. Then turn it another 90° and try again. Or try flipping the screen of the laptop back and forward at different angles. Doing this often yields wildly different performance numbers, depending on the distance of the...
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Radio systems in which each end can transmit and receive simultaneously. Typically two frequencies are used to set up the communication channel. Each frequency is used solely for either transmitting or receiving. Applies to Frequency Division Duplex (FDD) systems. Example: Cellular phones, satellite communication.
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These products are stamped with the Wi-Fi™ logo and referred to as Wi-Fi devices. 802.11a products will be stamped with the Wi-Fi5™ logo. The Wi-Fi logos certify that the product will work with any other Wi-Fi certified device, regardless of manufacturer. Network Topology Each component of a WLAN requires a radio transceiver and antenna.
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Hello, my name’s Nigel Bowden. Welcome to module 2 of the WiFi for beginners podcast. This is a series of podcasts discussing the fundamentals of wireless LAN networking. In each episode, we’ll take a look at a different aspect of WiFi to build your understanding and knowledge of wireless LAN networks.
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What is a wireless LAN & how does it work?
place to another. And when the network does something you aren’t expecting it to do, you will need a basic knowledge of the technology to do any kind of useful troubleshooting. How Wireless Networks Work Moving data through a wireless network involves three separate elements: the radio signals, the data format, and the network structure.
