| Wireless LAN (WLAN) is a wireless broadband | | | | GHz ) exhibit better range but with limited |
| technology that utilizes radio frequency (RF) to | | | | bandwidth and lower data rates. Higher |
| transmit and receive data through the air, | | | | Frequencies (5 GHz) have less range but higher |
| minimizing the need for wired networks. There | | | | data rates but is prone to blocking by solid |
| are two competing RF technologies in the use of | | | | objects. These are attributable to attenuation and |
| Wireless LAN, the IEEE 802.11 standard and | | | | interference. Attenuation or the loss of signal |
| proprietary technologies. Both fall under wireless | | | | strength during transmission is higher when the |
| broadband technology. Broadband means the | | | | receiver is farther from the transmitter. Obstacles |
| ability to transmit high-speed voice, data and | | | | such as mountains and buildings also contribute to |
| video traffic using a wide range of frequencies on | | | | attenuation by blocking or weakening radio signals, |
| a single wireless medium or device. This page | | | | causing signal loss or dead spots. Depending of |
| aims to give you an overview about Wireless | | | | what they are made of, floors, walls, and ceilings |
| Broadband -IEEE 802.11 standard commonly called | | | | can either strengthen or weaken WLAN signals. |
| Wireless LAN. 802.11 is a standard agreed by the | | | | Interference can be caused by nearby stations |
| IEEE (Institute of Electrical and Electronics | | | | operating in the same frequency on the same |
| Engineers, Inc.) the world's leading professional | | | | channel. 2.4 GHz cordless phones for instance can |
| association for the advancement of technology. | | | | cause great interference on 802.11b wireless |
| 802.11 is the standard adopted by IEEE to define | | | | networks. Wireless broadband and WLAN devices |
| an over the air interface between a wireless client | | | | are called transceiver devices since it both |
| and base station or between two wireless clients. | | | | transmit and receive at the same time. Each |
| The 802.11 standard has evolved over the years | | | | component both transmits and receives IP traffic. |
| and became one of the most successfully | | | | Antennas direct RF power into the air over a |
| deployed technologies. The standard now covers | | | | coverage area. An Antenna provides wireless LAN |
| 802.11b, 802.11a and 802.11g systems. Radio | | | | devices gain, direction and polarization. Gain is the |
| Frequency (RF) is the medium use by wireless | | | | measure of increase in power while direction is |
| networks in the transmission of information over | | | | the shape of the transmission pattern. Polarization |
| the air. RF works by converting electrical current | | | | is dependent on antenna alignment and can be |
| into radio waves and transmit those waves over | | | | typically described as vertical or horizontal. Most |
| the air using a defined frequency of the radio | | | | Access Point antennas are designed to operate in |
| spectrum. An example, the AM and FM radios | | | | vertical pattern for maximum horizontal coverage |
| two most commonly known uses of the RF | | | | plane or polarization. Putting the antenna in a |
| spectrum. The Federal Communications | | | | horizontal position will result in a vertical plane |
| Commission (FCC) is the one administering the | | | | limiting coverage. The factor to consider in |
| use of radio spectrum between the frequencies | | | | increasing the range of Wireless LAN devices is |
| of 9 Kilohertz (KHz) and 300 gigahertz (GHz). | | | | the Antenna and EIRP. EIRP or Equivalent |
| 802.11 WLAN systems operate in the radio | | | | Isotropically Radiated Power is being governed or |
| spectrum available to the public, also known as | | | | limited by FCC regulations to a maximum of Four |
| the unlicensed frequency band. These radio | | | | (4) watts with additional restrictions/limitations |
| spectrum bands are unlicensed, free for use by | | | | depending on type of antenna (directional or |
| anyone provided FCC regulations are complied | | | | omni-directional) and antenna placement (indoor or |
| with. The FCC as a regulatory governs the | | | | outdoors). Some countries limit EIRP to as much |
| maximum transmit power of wireless radios as | | | | as 100mw, above this will require a license to |
| well as, type of encoding and frequency | | | | operate. This applies mostly for outdoor WLAN |
| modulations to be used. In 802.11 operations, it is | | | | equipments. To deploy long-range outdoor |
| provided for by the FCC that non-licensed radios | | | | wireless broadband and WLAN devices, please |
| (such as 802.11) must accept interference from | | | | consult your country's telecommunication |
| licensed electronic systems. FCC considers licensed | | | | commission guidelines on use of outdoor wireless |
| device as the primary equipment. 802.11 Wireless | | | | broadband (WLAN) devices. The goal is to reach |
| LAN Standard Operating Frequencies: The 802.11 | | | | people yearning to start their own home-based |
| standard are assigned frequencies 2.4 GHz | | | | business even in remote regions thru |
| (2.4-2.4835 GHz) on ISM Band and 5 GHz | | | | cost-effective internet business and long-range |
| (5.15-5.25 GHz, G.25-5.35 GHz, 5.725-5.825 GHz) of | | | | wireless communication solutions. |
| the U-NII band. 802.11b and 802.11g operates on | | | | The author, Allan Amps is from the Telecom |
| 2.4 GHz while 802.11a is operating on the 5 GHz | | | | industry and has passion and interest in rural, |
| band. 802.11 assigned frequency range has | | | | remote internet connectivity solutions, wireless |
| different characteristics. Lower Frequencies (2.4 | | | | gadgets and internet home-based business. |