Wi-Fi Terms Explained

Town & City Centre wireless for CCTV is complicated enough without all the jargon and acronyms, we have listed below some of the common terms used within the IP Wi-Fi industry.

Also see our growing list of CCTV Terms and Descriptions in our VNR section.

AES - Advanced Encryption Standard

Approved by Wi-Fi Alliance for use with government files

ACM - Adaptive Coding and Modulation

Adaptive coding and modulation is a technology which can automatically change the modulation and forward error correct a link to compensate for changes in conditions - commonly weather (e.g. rain fade) and changes in radio frequency environment (e.g. level changes, interference).

The use of ACM eliminates the cost of service operatives

CSMA - Carrier Sense Multiple Access

Is a probabilistic media access control

DFS - Dynamic Frequency Selection

Is applied in wireless networks with several adjacent non- centrally controlled access points. The access points automatically select frequency channels with low interference levels.

DSL - Digital Subscriber Line

This is the medium by which data is transferred over regular phone lines to connect to the internet. However a DSL circuit is much faster than a regular phone connection.

DSSS - Digital Sequence Spread Spectrum

Direct- sequence spread-spectrum transmissions multiply the data being transmitted by a "noise"signal. The resulting effect is an enhanced signal to noise ratio.

ENCRYPTION

The process of encoding messages, information or data in such a way that only authorised users can read it, making it unintelligible to an unauthorised user. Cryptography offers enhanced security to the user.

Gbps/Kbps/Mbps - Gigabyte / Kilobit / Megabit Per second

This indicates the amount of data our products can transmit per second.

GHz / THz / KHz / MHz - Gigahertz / Terahertz / Kilohertz / Megahertz

This is the speed by which our products process data.

MIMO - Multiple In - Multiple Out

This is a data transfer accelerant. Multiple Input / Multiple Output increases the number of antennas at the transmitter and receiver to improve the devices performance. Transferring more data without requiring added bandwidth or drawing additional power.

PCB - Printed Circuit Board

The main board used in the manufacture of our products to mount components, providing the means of electrical connection between the components.

POE - Power Over Ethernet, power and data is combined over a single 8 core data cable. Also available POE+

PSU - Power Supply Unit

The power supply unit converts the power supply from AC to DC current in order to power our wireless transmission devices.

RF - Radio Frequency

The frequency by which our radios transmit signals to each other.

RMA - Return Merchandise Authorisation

This is the authorisation required in the unlikely event that a customer needs to return a product.

RSSI - Received Signal Strength Indicator

This is the measurement of power present in a received radio signal.

SSID - Service Set Identifier

A unique identification process which only allows the transfer of data between devices with the same unique identification. Enhancing security.

TDMA - Time division multiple access.

Is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. 

TPC - Transmit Power Control

Is a technical mechanism used to help prevent unwanted interference between different wireless networks.

ULTRA WIDEBAND

Used for cable replacement in systems that require wireless transmission of large amounts of data over a very short range, such as camcorders, HDTV and home entertainment.

WEP - Wired Equivalent Privacy

This is a wireless network security Standard, level 2/10.

Wi-Fi - Wireless Fidelity

Wireless technology which allows an electronic device to exchange data or connect to the internet using radio waves.

WiMax 

An alternative to wired broadband services e.g digital subscriber line (DSL) or cable modem. A technology standard for long-range wireless networking.

WLAN - Wireless Local Area Networking

Provides wireless network communication over short distances using radio or infrared signals instead of traditional network cabling. A WLAN typically extends an existing wired local area network by creating a bridge from the existing LAN (local area network) infrastructure to multiply WiFi clients within a limited area. As more WiFi capacity and throughput becomes available.

WPA - Wi-Fi Protected Access

This is a wireless encryption standard. Security Level 8/10.

WPA2 - Update of WPA

Advanced encryption standard approved by the Wi-Fi Alliance.

WPAN - Wireless Personal Area Network

A network interconnecting devices centred around an individual or a specific location in which the connections are wireless, negating the need for cabling. Enabling wireless communication via headsets, computers, printers, PDA's and mobile phones - Bluetooth

WWAN - Wireless Wide Area Network

Wireless WAN is a wide area network in which separate areas of coverage are connected wirelessly to provide service to a large geographical area.

Zigbee TM

This is a wireless protocol designed for small low power devices such as sensors for data transfer. Used for cable replacement in buildings and home automation systems to enable wireless communication between fire detection and suppression systems, home automation systems and physical security sensor systems

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Wi-Fi Installation


Main Wi-Fi page
Videcom are a nation Wi-Fi PtP installer, the majority of our work is in town and city centres in support of public safety CCTV systems. As a specialist installer we have a wealth of experience in installing and managing frequency allocation and spectrum usage in an increasingly congested free to air radio spectrum.

Videcom continue to look for solutions that combat these issues, including the greater use of licenced frequencies, time division multiplexing together with careful planning and site survey work.

Our installation teams are conversant with all the major problems found in heavily populated areas where multiple systems and users are all proving and utilising the same free to air 5.8 band. Occasionally we find there is no frequency availability to allow transmission and in these circumstances we look to the licenced frequencies, use of fibre optic cabling, optical laser links as well as alternative paths of communication.

How much bandwidth ?

A rough ready reckoner guide

We are often asked how much bandwidth should be allowed for CCTV camera. When utilising Wi-Fi this becomes a little more complex but for simplicity and to ensure design capacity we always recommend 4 Mbps for all cameras. But a note of caution, all radio links are quoted "up to" a designed throughput and this throughput diminishes the longer the link and is also affected by other systems installed nearby.

Can I use 24 GHz ?

Our understanding

There are many systems that are sold quoting long haul data transmission at 24 GHz, many of these systems are designed for export sales only. There are limits on power and distance when utilising 24 GHz systems in the UK. For the latest licencing regulations and requirements we recommend you contact OFCOM

Can I use 60 GHz ?

Yes

60 GHz from the likes of Siklu are an excellent choice for short hop high capacity links but come with a few installation warnings. The 60 GHz frequency suffers from "Rain Fade" and "Oxygen Absorption" causing signal loss particularly in heavy rain. But the benefits outweigh the disadvantages, if you need point to point high capacity interference free links then 60GHz may well be the answer.