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