Search results
Results from the WOW.Com Content Network
Wireless LAN (WLAN) channels are frequently accessed using IEEE 802.11 protocols. The 802.11 standard provides several radio frequency bands for use in Wi-Fi communications, each divided into a multitude of channels numbered at 5 MHz spacing (except in the 45/60 GHz band, where they are 0.54/1.08/2.16 GHz apart) between the centre frequency of the channel.
In wireless communications, channel state information (CSI) is the known channel properties of a communication link. This information describes how a signal propagates from the transmitter to the receiver and represents the combined effect of, for example, scattering, fading, and power decay with distance. The method is called channel estimation.
For very low-power systems, such as mobile phones, signal strength is usually expressed in dB-microvolts per metre (dBμV/m) or in decibels above a reference level of one milliwatt . In broadcasting terminology, 1 mV/m is 1000 μV/m or 60 dBμ (often written dBu). Examples. 100 dBμ or 100 mV/m: blanketing interference may occur on some receivers
The name Wi-Fi is not short-form for 'Wireless Fidelity', [34] although the Wi-Fi Alliance did use the advertising slogan "The Standard for Wireless Fidelity" for a short time after the brand name was created, [31] [33] [35] and the Wi-Fi Alliance was also called the "Wireless Fidelity Alliance Inc." in some publications. [36]
Bluetooth devices intended for use in short-range personal area networks operate from 2.4 to 2.4835 GHz. To reduce interference with other protocols that use the 2.45 GHz band, the Bluetooth protocol divides the band into 80 channels (numbered from 0 to 79, each 1 MHz wide) and changes channels up to 1600 times per second.
Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque ...
Original Wi-Fi uses 13 channels in the ISM bands from 2412 MHz to 2484 MHz in 5 MHz steps. The radio channel between an amateur radio repeater and an amateur radio operator uses two frequencies often 600 kHz (0.6 MHz) apart. For example, a repeater that transmits on 146.94 MHz typically listens for a ham transmitting on 146.34 MHz.
A wireless site survey, sometimes called an RF (Radio Frequency) site survey or wireless survey, is the process of planning and designing a wireless network, to provide a wireless solution that will deliver the required wireless coverage, data rates, network capacity, roaming capability and quality of service (QoS). [1]