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Wireless Networking Glossary of Acronyms & Phrases

1 | 2 | 3 | 4 | 5 | 8
A | B | C | D | E | F | G | H | I | J | K | L
M | N | O | P | Q | R | S | T | U | V | W | Y

This index of wireless and computer networking terminology, acronyms and phrases can provide a quick reference for wireless networking newcomers and more experienced installers alike. If there is a term that you are looking for isnít listed, feel free to contact us as we are happy to help.

1

10 Base-T - The basic Ethernet standard running at 10 Mbps

100 Base-T - Ethernet standard running at 100 Mbps

1000 Base-T - Ethernet standard running at 1000 Mbps

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2

2.4GHz - 2.4GHz is most commonly referring to the frequency range in which most 802.11b/g/n wireless networking equipment operates within. A wide range of competitively priced equipment operates on the 2.4GHz band that is widely referred to as Wi-Fi equipment that allows users to create networks wirelessly over ranges, typically, up to 250m. The 2.4GHz band has been unlicensed and free to operate on in the UK since 2003. More information can be found in our "Introduction to 2.4GHz Technology" article.

2G - Second Generation cellular networking standard. Refers to digital cellular and PCS wireless systems oriented to voice and low speed data services.

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3

3G - Third Generation cellular networking standard. Refers to the current generation of cellular wireless systems. Uses digital signal with high speed data and is standardized by 3GPP and 3GPP2. More information can be found in our "Introduction to 3G Technology" article.

3G Cellular Routers (Gateways) - Wireless Routers that operate on the 3G Cellular network rather than the conventional Ethernet based network. Ideal for mobile applications or for those who do not have Ethernet access. Please view our range of 3G Cellular Routers.

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4

4G - Fourth Generation cellular networking standard. Refers to the next generation of cellular wireless systems. Uses digital signal with ultra high speed data and is being standardized by 3GPP and IEEE. More information can be found in our "Introduction to 4G Technology" article.

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5

5GHz - 5GHz is most commonly referring to the frequency range in which most 802.11a/n wireless networking equipment operates within. It is quickly becoming popular for applications that require higher throughput and longer ranges such as backhaul services. The 5GHz band is unlicensed and licensed depending on the specific frequency used. More information can be found in our "Introduction to 5GHz Technology" article.

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8

802.11 - 802.11 is the generic name of a family of standards for wireless networking, commonly known as Wi-Fi, set by the Institute of Electrical and Electronics Engineers (IEEE). The numbering system for 802.11 comes from the IEEE, who uses "802" for many networking standards such as Ethernet (802.3). 802.11 standards define rules for communication on wireless local area networks (WLANs) with popular 802.11 standards including 802.11a, 802.11b and 802.11g and 802.11n. 802.11 was the original standard in this family, ratified in 1997 operating at 1-2 Mbps. This standard is obsolete today. More information can be found in our "Introduction to 802.11 (Wi-Fi) Technology" article.

802.11a - 802.11a is an IEEE standard in the 802.11 series. 802.11a operates in the 5GHz frequency band and supports a bandwidth of up to 54Mbps utilising OFDM. Due to 5GHz having greater nLoS capabilities, a smaller Fresnel Zone radius and less interference than 2.4GHz, 802.11a can sometimes give better results when applied indoors than 802.11b. 802.11a operates in the Licensed and Unlicensed 5GHz A, B and C Bands and therefore must meet Ofcom Regulations.

802.11b - 802.11b is an IEEE standard in the 802.11 series. 802.11b operates in the 2.4GHz frequency band and supports a bandwidth of up to 11Mbps utilising DSSS and CCK. 802.11b was the first "Wi-Fi" standard to become widely popular as its relatively low cost naturally resulted in many home and small business networks adopting it. Although 802.11b performs much better than traditional dial-up networking, the performance of 802.11b is still significantly less than other, newer standards such as its replacement, 802.11g. 802.11b operates in the Unlicensed 2.4GHz Band and must meet Ofcom Regulations.

802.11e, f, i, h - These are MAC layer 802.11 series standards that cover Quality of Service, Interconnection between APs, Spectrum and Transmit Power management and Security respectively.

802.11g - 802.11g is an IEEE standard in the 802.11 series. 802.11g operates in the 2.4GHz frequency band and supports a bandwidth of up to 54Mbps being the first to utilise multiple radios in one system. 802.11g has been the current "Wi-Fi" standard over the last few years to gain widespread usage. Although 802.11g performs much better than 802.11b, the performance of 802.11g is still significantly less than other, newer standards such as its replacement, 802.11n. 802.11g operates in the Unlicensed 2.4GHz Band and must meet Ofcom Regulations.

802.11n - 802.11n is an IEEE standard in the 802.11 series. 802.11n operates in the 2.4GHz and 5GHz frequency bands and supports a bandwidth of up to 150Mbps per data stream commonly utilising MIMO technology increasing throughput to go up to 300 and even 600Mbps and range significantly. 802.11n is the newest, popular "Wi-Fi" standard and is set to be the default for new equipment. 802.11n operates in the Unlicensed 2.4GHz Band and the Licensed and Unlicensed 5GHz A, B and C Bands and must meet Ofcom Regulations.

802.16 - The radio interface known as WiMax as specified by IEEE. See “Wi-MAX”.

802.16e - The most popular implementation of the IEEE 802.16 standard known as Mobile WirelessMAN or Mobile WiMAX.

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A

Access Point (AP) - An Access Point is a transceiver that connects users wirelessly to a local area network such as a WLAN or a fixed wire network via an Ethernet connection. Mobile users can connect to an Access Point within a defined range with the AP sending and receiving data within that area.

Ad-Hoc - A mode in which devices connect and communicate directly with each other, similar to a LAN peer-to-peer connection, without the use of any access point. The most commonly networking mode is Infrastructure Mode.

AES - An encryption method that uses up to 256-bit key encryption to secure data.

Antenna - The term used to describe Wireless Networking aerials. Antennas are devices used to transmit and receive data from a wireless networking device to another antenna in the wireless network. By reducing the area in which the signal is being radiated rather than just transmitting it in every direction, antennas can transmit to signal in a specific direction and therefore the signal "gains" strength. Each antenna is always connected to a bridge, which provides the physical connection to the local area network.

Antenna Gain - See "Gain (Antenna)".

Antenna Types - There are many types of antenna that give contrasting effects regarding the radiation of the signal. Antenna types include dish, flat panel, grid, helical, omnidirectional, patch, sector and yagi.

Attenuation - This is the technical term for a reduction in signal strength which in turn affects the performance of the wireless network. Attenuators can be purchased to reduce transmit power to stay within regulations.

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B

Backbone - The central conduit or main core of the network that supports very high capacity, high speed bandwidth that allows the sub networks to connect to and communicate with each other maximising performance and reliability. Also known as “Trunk”.

Backhaul - The intermediate link between the Backbone and a sub network requiring performance levels similar to the Backbone infrastructure itself.

Bandwidth - The maximum data rate or transmission capacity supported by a network connection, interface or communications channel at any point in time. Bandwidth, measured in bits per second (bps), represents the maximum speed at which data information can be sent across network connections with the higher the capacity, the greater the speed the data can flow. Can also be known as “Maximum Throughput”.

Base Station - See “Access Point”.

Beamwidth - This represents the interior angle of the 3 points made up by the transmitter and the points either side of the main radiation lobe where the signal strength is half the power of the main lobe i.e. 3dB less.

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C

Carrier Class - Refers to a system or a hardware or software component that is extremely reliable and well tested in its capabilities. Usually required to meet 99.999% availability providing very fast fault recovery through redundancy.

CAT5/CAT5e - Fifth generation, Ethernet network cable standard defined by the EIA and TIA. CAT5 is a twisted pair Ethernet technology cable and the most popular of all twisted pair cables in use today. CAT5 cable contains four pairs of copper wire supporting Ethernet speeds up to 100 Mbps. Although CAT5 cable usually contains four pairs of copper wire, Fast Ethernet communications only utilize two pairs. A newer specification for CAT5 cable, CAT5 enhanced, supports networking at speeds up to 1000 Mbps over short distances by utilizing all four wire pairs, and it is backward-compatible with ordinary CAT5. Though newer cable technologies like CAT6 and CAT7 are in development, CAT5 and CAT5e Ethernet cables remain the popular choice for most wired LAN connections because it is both affordable and supports high speeds.

CAT6 - Sixth generation, Ethernet network cable standard defined by the EIA and TIA. CAT6 is a twisted pair Ethernet technology cable containing four pairs of copper wire like the previous generation CAT5. Unlike CAT5, however, CAT6 fully utilizes all four pairs. CAT6 supports Gigabit Ethernet speeds up to 1Gbps and supports communications at more than twice the speed of CAT5e. An enhanced version of CAT6 called CAT6a supports up to 10 Gbps speeds.

CDMA (Code Division Multiple Access) - A channel access method employing spread-spectrum technology and a special coding scheme to allow multiple users to be multiplexed over the same physical channel. By contrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. CDMA is a form of spread-spectrum signalling, since the modulated coded signal has a much higher data bandwidth than the data being communicated.

Channels - Sub-frequency ranges within a main frequency band. Channels are created by dividing the main frequency range into smaller operating ranges that devices operate on allowing multiple devices to operate on the same main frequency band without interfering with each other. For example, the UK's 2.4GHz Band is split into 13 channels of 22MHz bandwidth.

Cloud Backup - A solution in which your data resides on an external server outside your home or office. Cloud backup solutions offer Data Encryption facilities so that data is compressed and encrypted so that others are unable to use them. Since the data that is backed up is on a remote location, there is a fair amount of disaster recovery is involved. Moreover, Cloud Storage servers will usually have data redundancy implemented internally.

Cloud Computing (Networking) - Concept whereby instead of purchasing hardware and networking infrastructure at a high capital expenditure, you simply outsource your computing resources to another company by renting the hardware and/or software from a service provider and gain access to them via the internet. Cloud Based Services can also offer remote usage of software packages resulting in a computer that could operate perfectly well with only an internet browser installed.

Cloud Managed Routers - Routers that feature Cloud based centralised management allowing users to operate their networks remotely via an internet browser without the need for deploying a local network monitoring solution.

Connectors - Antenna cabling use different interfaces to connect with devices. These include BMC, N, SMA and TNC with each end being a Plug or Jack (not Male or Female).

CPE (Customer Premises Equipment) - End User equipment such as WLAN Routers rather than equipment for Backhaul or Backbone deployment.

Custom Wi-Fi Solutions - 4Gon also supplies the individual components necessary for you to build your own, custom Wireless Networking hardware. Depending on the components and software used, you can build units that can function in exactly the same way as pre-built Point-to-Point links, Access Points, Mesh Nodes and more but with the ability to choose specific hardware that suits your every need. By building your own Custom Wireless Networking hardware, you get a product that is tailor made to your needs and in some cases can cost less than a similar, pre-built option.

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D

dB (Decibel) - A Standard Unit for measuring wireless signals. It is a logarithmic number where doubling the strength level adds 3dB and halving subtracts 3dB.

dBd (dB Dipole) - A value used to relate the gain of an antenna with a simple, dipole antenna consisting of two sections of wire. These are usually given for antennas designed to operate at frequencies less than 1GHz.

dBi (dB Isotropic) - This is a measurement of the gain of an antenna in a particular direction relative to an isotropic radiator (equal radiation in every direction). The larger the value the greater the gain. These are usually given for antennas designed to operate at frequencies greater than 1GHz.

DFS (Dynamic Frequency Selection) - This is the radio's ability to automatically detect and act by switching to another channel when another device appears to interfere with the signal to avoid loss in performance. This is required by Ofcom Regulations for devices operating in the 5GHz Band.

DHCP (Dynamic Host Configuration Protocol) - DHCP is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the network to allow a computer to join an IP-based network without having a pre-configured IP address. Home network equipment like broadband routers offers DHCP support for added convenience in joining home computers to the LAN.

Diffraction - Propagation mode where radio waves are bent around sharp edges. For example, this mode is used to send radio signals over a mountain range when a line-of-sight path is not available. However, the angle cannot be too sharp or the signal will not diffract. The diffraction mode requires increased signal strength, so higher power or better antennas will be needed than for an equivalent line-of-sight path. Also known as “Knife-Edge Diffraction”.

Directional Antenna - These offer significantly reduced beamwidths to focus the signal to increase operating range or signal strength. Directional antennas include dish, grid, patch, and yagi types.

Dish Antenna - Your conventional, concave, dish shaped antenna that reflects signal onto a transmitter or receiver located in front of the dish at the focal point. Dish antennas typically have very high gain values by focusing the signal into a very narrow beam to achieve links of vast distances.

Distance Between Points - The distance between your link devices is affected by various factors including transmit power, antenna gain, loss of signal on the path over air, receiver sensitivity and more. Links over ranges of 2km are quite common with those up to 10km becoming less so. Links going up to around 100km have been achieved by these are very rare. For more information, please refer to our “Path Loss, Link Budget & System Operating Margins” article.

Diversity - An antenna system that uses multiple antennas to reduce interference and maximise reception and transmission quality of out of phase signal due to multi-path refraction and reflection.

Downleads - A cable connecting an antenna with a wireless device usually made of low loss co-axial cable such as Type 195, Type 400 or Type 600 cable. These cables are referred to as Downleads if they are long whereas shorter cables are referred to as Pig-Tails.

DSSS (Direct Sequence Spread Spectrum) - A type of single radio transmission technology that includes a redundant bit pattern to lessen the probability of data lost during transmission. Other radios without DSSS cannot identify the signal and ignore it.

Dual Band - A device that is capable of operating in two frequencies. On a wireless network, typical dual-band devices are capable of operating in both the 2.4GHz and 5GHz bands.

Dumb Access Points - This architecture uses access points that provide as little functionality as possible and cannot operate independently of one or more central WLAN switches. The access points encapsulate user traffic and control information into tunnels and forward these packets to a central WLAN switch for processing. The switch provides a central management and control point for the entire network and consolidates all security functionality. However, routing all traffic to a central location requires participation of all network elements and creates a performance bottleneck. Also known as “Thin”, “Centralised” and “Lightweight” Access Points.

DWDM (Dense Wavelength Division Multiplexing) - A technique for increasing the bandwidth of optical network communications by allowing dozens of different data signals to be transmitted simultaneously over a single fiber. To keep the signals distinct, DWDM manipulates wavelengths of light to keep each signal within its own narrow band.

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E

E.I.R.P (Effective Isotropically Radiated Power) - This is a combination of the output power of the transmitter and the gain of the antenna. Depending on the Frequency Band that devices are operating in, they must not exceed certain E.I.R.P values i.e. 20dBm or 100mW for the 2.4GHz Band. A rough guide to calculate the E.I.R.P of your system is to add the Tx Output Power and Antenna Gain together.

EDGE (Enhanced Data rates for Global Evolution) - 3G compliant standard that enabled the transmission of large amounts of data at up to 384kbps and was designed to enable the delivery of multimedia and other broadband applications to mobile phone and computer users. EDGE has been deployed in existing GSM 800, 900, 1800 and 1900MHz frequency bands and complements UMTS technology using the same TDMA frame structure, logic channel and 200kHz carrier bandwidth as today's GSM networks, which allowed the existing cell plans to remain intact.

Encryption - Any procedure used in cryptography to translate data into a form that can be decrypted and read only by its intended receiver. Encryption methods include WEP, TKP, WPA and WPA to name a few.

Encryption Key - A codeword that is used encrypt data based on an algorithm when transmitting wirelessly. For another device to decrypt the data, it must also know the key which is entered when trying to initially access the network. This improves security of wireless transmissions.

Enterprise - Enterprise Class Networks are usually deployed in large businesses catering for hundreds or thousands of clients that require high throughput and almost 100% availability where the access to the network is mission critical. Enterprise Class equipment is therefore usually more expensive but with much higher performance potential.

Ethernet - A physical and data link layer technology; it is the most popular international standard for wired Local Area Networks (LANs).

Ethernet Bridge - Consists of 2 devices (in our case Wireless) communicating directly with each other to transfer data between LANs, typically at Ethernet speeds or higher. A bridge device filters data traffic at a network boundary reducing the amount of traffic on a LAN by dividing it into two segments operating at the data link layer (Layer 2) of the OSI model inspecting incoming traffic and deciding whether to forward or discard it.

ETSI (European Telecommunications Standards Institute) - An independent, non-profit, standardisation organisation in the telecommunications industry in Europe, with worldwide projection. ETSI has been successful in standardising the Low Power Radio, Short Range Device, GSM cell phone system and the TETRA professional mobile radio system.

EV-DO (Evolution Data Only) - High-speed, cellular network protocol used for wireless data communications and primarily Internet access. EV-DO is considered a broadband technology like DSL or cable modem Internet services. Various external modems exist to enable computers and handheld devices for EV-DO. Downlink bandwidths have peaked as high as 9Mbps on Revision B.

External Antenna (Connectorised) - A phrase that states that a Wireless Networking device has the capability to have an external antenna attached to it for operation which allows the user to buy a specific antenna suited for their application. This usually means, however, that there is no integrated antenna in the device.

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F

Fade Margin - See “System Operating Margin”.

FCC (Federal Communications Commission) - The Federal Communications Commission regulates interstate and international communications by radio, television, wire, satellite and cable in all 50 states, the District of Columbia and U.S. territories.

Femtocell - Small base station coverage area, typically designed for use in a home or small business. It connects to the service provider's network via broadband typically supporting 2 to 4 active devices in a residential setting, and 8 to 16 devices in enterprise settings. A Femtocell allows service providers to extend service coverage indoors, especially where access would otherwise be limited or unavailable. It is the smallest of the “cell” types with a typical range of around 10m.

FHSS (Frequency Hopping Spread Spectrum) - A system where transmitters send short bursts of data over a channel before moving onto another and repeating the process.

Fiber Optic Cable - Network cable that contains strands of glass fibers inside an insulated casing. These cables are designed for long distance and very high bandwidth (1000Mbps+) network communications. Fiber optic cables carry communication signals using pulses of light. Whilst expensive, these cables are being increasingly used instead of traditional copper cables because fiber offers more capacity and is less susceptible to electrical interference.

Firewall - Security to protect a computer network from unauthorized access. Network firewalls may be hardware devices, software programs, or a combination of the two guarding an internal computer network (home, school, business intranet) against malicious access from the outside by viruses and other service preventing attacks i.e. DoS. Network firewalls may also be configured to limit access to the outside from internal users.

Firmware - Software routines that are embedded as read-only memory (ROM) in a computer chip or hardware device to prevent modification of the routines. These routines control how devices operate with newer firmware likely fixing bugs or providing new features. Unlike random access memory (RAM), read-only memory stays intact in the absence of electrical power. Startup routines and low-level input/output instructions are stored in firmware.

Flat Panel Antenna - These can provide relatively high gain figures whilst being physically smaller or low profile in areas where there is a lack of space or aesthetic quality of the installation area must be maintained.

Free Space Loss (FSL) - Attenuation of signal path or the drop in the density of power of the wireless transmission's wave as it propagates (travels) through a medium over a distance. It is an important element when it comes to the design and planning of a Wireless Network and is a key factor when calculating the link budget. Also known as “Path Loss”. For more information, please refer to our “Path Loss, Link Budget & System Operating Margins” article.

Free Space Optics (FSO) - Technology that uses laser beams via a line of sight optical connection to transfer data, video or voice communications across areas ranging typically from 100m to a few kilometres at throughput bandwidths up to 1.25Gb/s at frequencies above 300GHz of wavelengths, typically, 785 to 1550nm. More information can be found in our "Introduction to Free Space Optics (FSO)" article.

Frequency Range (Bands) - Areas of the spectrum that are designated for use with Wireless Networking equipment; usually stated by listing the upper and lower bounds i.e. 5GHz Band A = 5.150 - 5.350GHz.

Fresnel Zone - The area around the line-of-sight path between WLAN bridge antennas that radio waves spread out into after they leave the antenna. This area must be clear or the strength of the signal will weaken. Usually in the installation of wireless bridges, it is a common rule that no more than 60% of the 1st Fresnel Zone must be blocked for good wireless transmission performance. For more information, please refer to our “Fresnel Zones” article.

Front-to-Back Ratio (Front-to-Rear) - The ratio of the gain from the front of the antenna to the gain from the rear of the antenna. A directional antenna will nearly always radiate some signal out of the rear of the antenna so the Front-to-Back Ratio shows the efficiency of its forward radiation. A figure around 15dB should be the minimum of a good antenna with 20dB or above being acceptable. The higher the ratio, the more directionally efficient the antenna.

Full Duplex - Allows communication in both directions, and, unlike half-duplex, allows this to happen simultaneously. A good analogy for a full-duplex system would be a two-lane road with one lane for each direction. Full-duplex Ethernet connections work by making simultaneous use of two physical pairs of twisted cable (which are inside the jacket), wherein one pair is used for receiving packets and one pair is used for sending packets (two pairs per direction for some types of Ethernet), to a directly connected device. This effectively makes the cable itself a collision-free environment and doubles the maximum data capacity that can be supported by the connection.

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G

Gain (Antenna) - A value stated in dBi, Antenna Gain is the ratio of the intensity of the radiation in a particular direction by the antenna compared to if it radiated the signal evenly in all directions. When an antenna receives or transmits signal, it is focused in a certain direction or plane and that reduction in coverage area by intensifying it in a reduced area is the gain. Even antennas that radiate in all directions on a specific plane, such as an omnidirectional antenna, have gain because they are reducing the signal transmission significantly on the vertical plane.

Gateway - In the wireless world, a gateway is an access point with additional software capabilities such as providing NAT and DHCP. Gateways may also provide VPN support, roaming, firewalls, various levels of security, etc.

GHz (Gigahertz) - The typical unit of frequency when discussing Wireless Networking RF Signals. 1GHz is equal to 1000MHz (Megahertz) or 1,000,000,000Hz (Hertz) and represents the signal being equivalent to 1,000,000,000 cycles in a period of second. Most Wireless Networking equipment's operating frequencies are stated in GHz such as the 2.4GHz Band or 5GHz Band.

Gbps (Gigabit per second) - See "Mbps (Megabit per second)".

GPRS (General Packet Radio Service) - A packet-based wireless communication service that, when available in 2000, promised data rates from 56 up to 114 Kbps and continuous connection to the Internet for mobile phone and computer users.

Grid Antenna - These are much like the parabolic dish antennas but the permeable grid design lets wind pass through, leaving your wireless communications undisturbed whilst still being highly directional.

GSM (Global System for Mobile Communication) - A digital mobile telephone system that is widely used in Europe and other parts of the world. GSM uses a variation of TDMA and is the most widely used of the three digital wireless telephone technologies (TDMA, GSM, and CDMA).

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H

Half Duplex - Allows communication in both directions, but only one direction at a time (not simultaneously). Typically, once a party begins receiving a signal, it must wait for the transmitter to stop transmitting, before replying (antennas are of trans-receiver type in these devices, so as to transmit and receive the signal as well). A good analogy for a half-duplex system would be a one-lane road with traffic lights at each end. Traffic can flow in both directions, but only one direction at a time, regulated by the traffic lights. See “Full Duplex”.

Helical Antenna - A helical antenna is an antenna consisting of a conducting wire wound in the form of a helix coil. Helical antennas can operate in one of two principal modes, normal mode or axial mode. In the normal mode, the dimensions of the helix are small compared with the wavelength and the radiation pattern is similar to those of an omnidirectional antenna. The radiation is linearly polarized parallel to the helix axis. In the axial mode, the dimensions of the helix are comparable to a wavelength and the antenna radiates a beam off the ends of the helix, along the antenna's axis. It radiates circularly polarized radio waves and is extremely directional.

High Capacity Wireless - Wireless Networking equipment that supports high bandwidth giving fast data rates or allowing many simultaneous connections through the same device without adversely affecting performance.

HotSpot - A location where Wi-Fi network access (usually Internet access) is made publicly available, often found in airports, hotels, coffee shops, and other places where business people tend to congregate. Hotspots are considered a valuable productivity tool for business travellers and other frequent users of network services. Technically speaking, hotspots consist of one or several wireless access points installed inside buildings and/or adjoining outdoor areas where these APs are typically networked to printers and/or a shared high-speed Internet connection. Some hotspots require special application software be installed on the Wi-Fi client, primarily for billing and security purposes.

HSDPA (High-Speed Downlink Packet Access) - 3G protocol for data communications on cellular networks. HSDPA supports theoretical data rates of 1.8 Mbps and up to 14.4 Mbps maximum, although typical speeds are closer to 500 Kbps.

HSUPA (High-Speed Uplink Packet Access) - 3G protocol for data communications on cellular networks. HSDPA is specialised for higher upload speeds supporting theoretical data rates of 1 Mbps and up to 5.76 Mbps maximum uplink.

Hybrid Network - Combination of two or more topologies in such a manner than the resulting topology is not representative of a standard one i.e. a star network connected to a ring or bus network.

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I

IDU (Indoor Unit) - A networking device that is designated for indoor use only.

IEEE - A global, technical, professional society and standards setting organization serving the public interest and its members in electrical, electronics, computer, information and other technologies. Creators of the 802. standards family.

Indoor Wi-Fi Solutions - Essentially a small scale Point-to-Multipoint system, an Indoor Wi-Fi network allows users to access WLAN networks and wireless broadband coverage throughout an indoor environment such as an enterprise business, an industrial space such as a warehouse or a medical facility or a Small-Office-Home-Office building.

Infrastructure mode - A legacy term used to describe a wireless network consisting of devices connected to a network using a centralized wireless access point. One of two types of wireless network modes; the other being ad hoc.

Integrated Antenna - The Wireless Networking device has an antenna built into the housing of the device so that no external antenna is needed.

Interference - Distortion of the wireless signal, be it from other RF wave sources or through phase shift with its own signal at the receiver. This weakens the wireless signal causing performance loss.

IP (Internet Protocol address) - Logical address for a network adapter that uniquely identifies computers on a TCP/IP network. An IP address can be private, for use on a local area network (LAN), or public, for use on the Internet or other wide area network (WAN). IP addresses can be determined statically (assigned to a computer by a system administrator) or dynamically (assigned by another device on the network on demand) and function in the same way as your postal address (so the computers know where to send the signal). Two IP addressing standards are in use today. The IPv4 standard is most familiar to people and supported everywhere on the Internet, but the newer IPv6 standard is planned to replace it and is currently in deployment. An example of an IPv4 address could be 123.456.789.012.

IPSEC - A Layer 3 authentication and encryption protocol that is commonly used to secure VPNs.

ISM band - The 2.4GHz Band that a wide range of Wi-Fi equipment operates in. The industrial, scientific and medical (ISM) radio bands were originally reserved for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than communications. The powerful emissions of these devices can create interference and disrupt radio communication using the same frequency so communications equipment operating in these bands must accept any interference generated by ISM equipment.

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J

Jitter - is often used as a measure of the variability over time of the packet latency across a network. A network with no jitter has a constant latency. Packet jitter is expressed as an average of the deviation from the network mean latency. However, for this use, the term is imprecise. The standards-based term is packet delay variation (PDV) is an important quality of service factor in assessment of network performance.

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K

kbps (Kilobit per second) - See "Mbps (Megabit per second)".

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L

LAN (Local Area Network) - Supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home being useful for sharing resources like files, printers or other applications. A LAN in turn often connects to other LANs, and to the Internet or other WANs. Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs but are restricted by wires. Wireless LAN and other more advanced LAN hardware options also exist.

Last Mile Technology - Telecommunications technology that carries signals from the broad telecommunication infrastructure along the relatively short distance (hence, the "last mile") to and from the home or business. This is a term that often refers to the supply of broadband access to areas that are just outside the area of access to the wired network infrastructure.

Latency - Measured either one-way or round-trip. Round-trip latency is more often quoted, because it can be measured from a single point. Many software platforms provide a service called ping that can be used to measure round-trip latency. Ping performs no packet processing; it merely sends a response back when it receives a packet (i.e. performs a no-op), thus it is a relatively accurate way of measuring latency. This gives you the time in milliseconds for the trip to take place. The lower the latency, the better the performance of the network.

Leaky Feeder - Leaky Feeder provides a signal along the whole length of the cable.

Leased Line - Connects two locations for private telecommunication service, however, it is not a dedicated cable. A leased line is actually a reserved circuit between two points and can span short or long distances. They maintain a single open circuit at all times and are most commonly are rented by businesses to connect branch offices because these lines guarantee bandwidth for network traffic. Individuals can theoretically also rent leased lines for high-speed Internet access, but their high cost (often more than £1000 per month) even deters businesses. Wireless Backhaul services can replace the need for purchasing a leased line.

License Exempt - Wireless devices that operate in license exempt bands can operate without being permitted a license of use by the relevant Regulatory Organisation i.e. 2.4GHz equipment can operate without being granted a license of use by Ofcom.

Link Budget - A calculation that takes into account all of the gains and losses throughout the link, from the transmitter, to the air and then through the receiver. It looks at signal propagation, antenna gains and other losses from factors such as terrain effects and humidity etc. For more information on calculating Link Budget, please refer to our “Path Loss, Link Budget & System Operating Margins” article.

LMR 195/WBC 195 - Co-axial cable with the following features: SMA, BNC and TNC connector support, waterproof, 0.62dB loss at 2.4GHz, 0.98dB loss at 5GHz, 5mm diameter, durable, flexible and relatively inexpensive.

LMR 400/WBC 400 - Co-axial cable with the following features: N, SMA and TNC connector support, waterproof, 0.35dB loss at 2.4GHz, 0.22dB loss at 5GHz, 11mm diameter, durable and slightly more expensive.

LMR 600/WBC 600 - Co-axial cable with the following features: N connector support, waterproof, 0.14dB loss at 2.4GHz, 0.238dB loss at 5GHz, 15mm diameter, very durable and relatively expensive.

LoS (Line-of-Sight) - A clear path between both Wireless Networking devices. This is a vital characteristic for high performing, long distance links when objects intruding on the 1st Fresnel Zone can have a dramatic impact on Availability. Note that a clear optical line of sight does not mean a clear line of sight for networking antennas. For more information, please refer to our "Fresnel Zones" article.

Low Loss Cable - In most cases this refers to Low Loss Co-Axial cable. See “RF Coaxial Cable”.

LTE (Long Term Evolution) - 3G protocol for data communications on cellular networks. It has experienced peak download rates of 326.4 Mb/s and 172.8 Mb/s for 4x4 and 2x2 MIMO antennas respectively when using 20 MHz of spectrum and peak upload rates of 86.4 Mb/s for every 20 MHz of spectrum using a single antenna. This means that it does not quite meet the 4G requirements but it is still often branded as 4G by telecommunications providers as it offers a considerable increase in performance over 3G. Its radio interface is often referred to as E-UTRA (Evolved UMTS Terrestrial Radio Access).

LTE-Advanced - 4G protocol for data communications on cellular networks. LTE Advanced is not a new technology but rather an enhancement to the existing LTE standard by using multiplexing and additional spectrum range to achieve the speeds required for 4G; whilst help for system capacity usage is dealt with by co-ordinated multi point transmissions. LTE-Advanced can use up to 8x8 MIMO antennas and 128 QAM (Quadrature Amplitude Modulation) giving performance of almost 3.3Gb/s peak download rates per sector of the base station using 100MHz aggregated bandwidth under perfect conditions. With new developing technologies such as smart antennas and advanced network infrastructures, LTE Advanced will take a good few years to become fully developed and integrated.

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M

MAC Address (Media Access Control Address) - Media Access Control assigns a unique number to each IP network adapter called the MAC address. A MAC address is 48 bits long and is commonly written as a sequence of 12 hexadecimal digits as follows: 07:E0:17:8F:11:2F

Macrocell - Large base station coverage area, typically found in rural areas or along highways. An example of usage would be a large office, a mall, or train station. The term Macrocell is used to describe the widest range of cell sizes that usually provides network coverage served by a high power base station (i.e. cellular tower), and generally, Macrocells provide larger coverage areas than Microcells. Typical range is more than 2km

Mbps (Megabit per second) - Data rate unit of a computer network. Connections are measured in units of bits per second (bps) but manufacturers typically rate their products using larger scale units such as Mbps. Please note that bits per second are not the same as bytes per second as you may often see file transfer and file download speeds on your computer shown in Kilobytes per second (KBps) or Megabytes per second (MBps) but these are not used when discussing network bandwidth speeds in Wireless Networking or Internet Service Provider speeds.

  • 1000 bps = 1 kbps
  • 1000 kbps = 1 Mbps
  • 1000 Mbps = 1 Gbps
  • 8 bps = 1 Bps
  • 8 kbps = 1 kBps
  • 8 Mbps = 1 MBps
  • 1000 Bps = 1 kBps
  • 1000 kBps = 1 MBps
  • 1000 MBps = 1 GBps

Where,

  • bps = Bits per second
  • kbps = Kilobits per second
  • Mbps = Megabits per second
  • Gbps = Gigabits per second
  • Bps = Bytes per second
  • kBps = Kilobytes per second
  • MBps = Megabytes per second
  • GBps = Gigabytes per second

i.e. 100 Mbps would be equal to 12.5 MBps.

Mesh Networks - Cost effective way of providing wireless connectivity easily over a large area using wireless mesh “nodes” to communicate between each other to spread the network. Traditional Wi-Fi networks rely on a small number of wired access points to provide Hotspots for users to connect to whereas with Mesh Networks, there only has be at least one node connected to a wired, Ethernet connection with the other nodes connecting to it through neighbouring nodes. Data travels across the network from one point to another by hopping wirelessly from one mesh node to the other. The nodes automatically determine the quickest and most reliable path in the process known as dynamic routing, switching paths and re-providing connectivity if one fails.

Microcell - Relatively large base station coverage area, typically covering a limited area such as a mall, a hotel, or a transportation hub. A Microcell is usually larger than a Picocell, though the distinction is not always clear with Microcells using power controls to limit the radius of its coverage area. Typical range is less than 2km wide but larger than 200m.

MIMO (Multiple-Input-Multiple-Output) - A signal processing technology that uses multiple receivers and multiple transmitters in both the client and access point to achieve higher throughput performance. MIMO devices utilise the same network protocols and signal ranges that non-MIMO devices do but achieve higher performance by more aggressively transmitting and receiving data over multiple channels. MIMO signalling technology can increase network bandwidth, range and reliability at the potential cost of interfering with other wireless equipment. The exact number of antennas utilised in a MIMO device can vary with typical devices containing three or four antennas instead of the single antenna that is standard in all earlier forms of equipment.

Mounting Kit - A kit that is designed to help in the installation of an external antenna or wireless networking device system.

mPCI - Mini PCI Card Bus connector for use with many small, wireless cards that can be fitted to wireless router boards or into PCI adaptors so that they are compatible with PCI bus.

Multipath - Multiple copies of the original transmitted signal occur due to reflections, scattering, etc. which can lead to Multipath Distortion when parts of the same radio wave arrive at a receiver at different times.

mW (Milliwatt) - Unit of power where 1000 mW is equal to 1 W. Power outputs and radiated powers are often listed in terms of mW for Wireless Networking equipment where there are regulations that limit these. To view a conversion table between Decibels and Milliwatts, please refer to our “References Section” article.

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N

NAT (Network Address Translation) - A network capability that enables multiples of computers to dynamically share a single incoming IP address from an internet connection. NAT takes a single incoming public IP address and translates it to a new private IP address for each client on the network.

nLoS (Near Line-of-Sight) - If there are some minor obstructions penetrating the Fresnel zone this would be considered as a near line of sight (nLOS) application. Most Wireless Networking Bridges will perform acceptably in nLOS scenarios but you will see some performance degradation depending on the number of obstacles and how deep they penetrate the Fresnel zone.

NLoS (Non Line-of-Sight) - If you cannot optically see the other device from the other device's location then this is considered non line of sight (NLOS). Wireless Networking equipment does not perform well under these conditions but a weaker link may be just possible. If may be better to consider using a repeater that is offset from the main path to bypass the obstacle.

Node - Any device connected to a computer network such as computers, PDAs, cell phones, or various other network appliances. On an IP network, a node is any device with an IP address.

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ODU (Outdoor Unit) - A networking device that is designated specifically for outdoor use usually being weatherproof and secure.

Ofcom - Ofcom is the UK's communications regulator who regulates the TV and radio sectors, fixed line telecoms and mobiles, plus the airwaves over which wireless devices operate. To obtain a license for operating Wireless Networking equipment in regulated frequency bands, you need to apply to Ofcom.

OFDM (Orthogonal Frequency Division Multiplexing) - The technique used most popularly with 802.11n devices that subdivides each radio channel into narrower frequency ranges. It achieves higher performance than spread spectrum techniques by splitting a data stream into multiple narrowband streams that are sent in parallel. Each one can use simpler modulation than would be required for the complete data stream, making the signal less vulnerable to interference or multipath effects.

Omnidirectional Antenna - An external antenna that radiates signal in evenly in almost 2 dimensions only, much like a circle pattern with a slightly protruding top and underside. They are particularly useful for use in areas where you want to supply network access to a large, local area on the same vertical height such as a HotSpot in a public park.

Outdoor Wi-Fi Solutions - Outdoor Wi-Fi networks are very similar to their Indoor counterparts but with a few differences that validate their outdoor branding that can include weatherproof capabilities, high transmission power levels, support for WDS systems and more.

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P

Patch Antenna - See “Flat Panel Antenna”.

Path Loss - See “Free Space Loss (FSL)”.

PCI Card - Wireless PCI cards can be fitted into wireless router boards that can also have integrated antennas built in on the board itself and are typically plug and play. PCI defines the electrical characteristics and signal protocol used for two devices to communicate over a computer's central bus. PCI network adapters and other devices exist in several different shapes and sizes called "form factors."

Picocell - Smaller base station coverage, typically found covering small areas such as in-building (offices, shopping malls, train stations, etc.) or more recently in-aircraft. Picocells are typically used to extend coverage to indoor areas where outdoor signals do not reach well, or to add network capacity in areas with very dense network usage. Picocells provide coverage and capacity in areas difficult or expensive to reach using the more traditional Macrocell approach. Typical range is usually is 200 meters or less.

Pigtail - Typically a short, low loss cable that used to connect the wireless device and the downlead for the last part of the connection where high flexibility is required that the downlead may not offer.

Planar Antenna - See “Flat Panel Antenna”.

Planning Permission - It is always a good idea to check with your Local Planning Authority before installing an outdoor Wireless Networking device as many buildings have restrictions in place regarding the total amount of satellite dishes or antennas that may be mounted and also the location in which they must sit. Buildings may also be listed or under conservation that would not allow any modification to the structure or aesthetics.

PoE (Power-over-Ethernet) - Quite often the mains power connection is located far away from the actual Wireless Networking device to keep it as close as possible to an external antenna to avoid the use of long co-axial cables. This could cause a problem as supply of power to the unit may not be possible, however, the use of Power-over-Ethernet can be utilised which uses the four spare cores in the eight core Ethernet cable to carry the power supply to the device. Normally this is done via a PoE injector at the end of the cable near the mains that connects to the LAN and also the low voltage power supply transformer, and another PoE injector at the other end to work in reverse supplying splitting the power supply from the data stream to power the device and the forward the data transmission. Voltage levels can drop when using Ethernet cable in this way so various PoE injector ratings are available such as 12V, 24V and 48V but care must be taken as to not damage equipment as some devices will be damage if over-powered. For more information, please refer to our "Power over Ethernet Guide" article.

Point-to-Multipoint (PtMP) - Wireless, Point-to-Multipoint links can create scalable, interference-resistant networks that have the capacity to work with many static or mobile end points whilst offering high bandwidth speeds allowing subscribers to connect to the same network across varying locations. From small building WLANs to large, bandwidth intensive Metro Networks, Point-to-Multipoint solutions come in all sizes catering for a multitude of situations.

Point-to-Point (PtP) - Wireless, Point-to-Point Ethernet Bridges can connect two remote locations together to create a network link between each other allowing large organisations to single users to connect LANs that can share valuable data where it is required without the costly infrastructure issues involving cabling. With the evolution of Point-to-Point backhaul technology, it has become a viable way of creating network links in competition with leased lines, being easier and quicker to deploy.

Polarisation - Refers to the plane on which the signal is being transmitted, usually Horizontal, Vertical or Circular. If two polarising antennas are not aligned correctly, signal can be completely lost.

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Q

QAM (Quadrature Amplitude Modulation) - Modulation scheme where the amplitude of two waves, 90 degrees out-of-phase with each other, are changed to represent the data signal. Amplitude modulating two carriers in Quadrature (90 degree phase shift) can be equivalently viewed as both amplitude modulating and phase modulating a single carrier. Phase-Shift Keying (PSK) can be regarded as a special case of QAM, where the magnitude of the modulating signal is a constant, with only the phase varying. Frequency-Shift Keying (FSK) can also be regarded as a special case of phase modulation. QAM is used extensively as a modulation scheme for digital telecommunication systems with spectral efficiencies of 6 bits/s/Hz being achievable.

QoS (Quality of Service) - Refers to a wide range of networking technologies and techniques with the target being a supply of guarantee on the ability of a network to deliver predictable results. Elements of network performance that are covered by QoS often include availability, bandwidth, latency, and error rate. QoS involves prioritisation of network traffic and can be targeted at a network interface, toward a given server or router's performance, or in terms of specific applications. A network monitoring system must typically be deployed as part of QoS to insure that networks are performing at the desired level. QoS is also becoming especially important for the latest generation of Internet applications such as VoIP, video-on-demand and other consumer services where stable performance levels are critical.

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Radiated Power Levels - See “E.I.R.P”.

RADIUS - A standard technology used by many major corporations to protect access to wireless networks. RADIUS is a user name and password scheme that enables only approved users to access the network but does not affect or encrypt data. The first time a user wants access to the network they must input his or her name and password and submit it over the network to the RADIUS server which in turn verifies that the individual has an account. RADIUS can also be set up to provide different access levels or classes of access, for example, one level can provide blanket access to the Internet; another can provide access to the Internet as well as to email communications; yet another account class can provide access to the Net, email and the secure business file server.

Range - The range of your Wireless Network will depend on a lot of factors including the surrounding environment, the equipment used and the requirements of your network performance. Most systems can operate over many hundreds of meters linking buildings together without trouble or providing network access to a wide area. For more information on calculating your permissible network range, please refer to the following articles: "Factors Affecting Wireless Networking Performance", "Fresnel Zones" and "Path Loss, Link Budget & System Operating Margins".

Receiver - A device that receives the signal sent by the transmitting device and passes it on to further devices to interpret.

Receiver Sensitivity - The receiver sensitivity is a very important aspect when it comes to the performance of your network. Even if the transmitter was radiating huge amounts of strong signal, if the receiver sensitivity was not of a good enough level, the receiver would be "deaf" to the signal. On the other hand, if the receiver is very sensitive and the transmitted signal is weak, the receiver may still be able to pick up a good signal. Measured in dB, receiver sensitivity is better the lower the value; due to the figures generally being below zero i.e. -80dB sensitivity is better than -60dB. In general, the receiver sensitivity will reduce as throughput speeds increase i.e. at 10Mbps it may be -80db but at 100Mbps it may be -60dB. Therefore you can see that even though a link may be possible, the maximum permissible speeds may be low but this may be better than no link whatsoever.

Repeater - Device that extends the coverage of an existing access point by relaying its signal. A wireless repeater does not do intelligent routing that is performed by wireless bridges and routers etc.

Residential Gateway - Wireless device that allows multiple devices accessing a home network, including PCs and peripherals to access the Internet and communicate with one another.

RF Coaxial Cable - Coaxial cable, or coax, is an electrical cable with an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. One advantage of coax over other types of radio transmission line is that the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines, and provides protection of the signal from external electromagnetic interference; because of this the low loss makes it perfect for use with your Wireless Networking systems but can be relatively expensive. For more information, please refer to our "Wireless Networking Cables Guide" article.

RF Power Level - Power levels are stated in dBm or mW. To view a conversion table between Decibels and Milliwatts, please refer to our “References Section” article.

RFID (Radio Frequency Identification) - An electronic identification technology that uses radio frequency signals to read identifying data contained in tags on equipment in a similar way to how bar codes work.

RG174 - 3 mm diameter cable for MMCX cable connectors. Relatively cheap but looses signal strength quickly over distance and therefore is not recommended for antenna connections.

RG58 - 5mm diameter, relatively lossy coaxial cable that is common but not recommended for antenna connections. RG58 is often used in marketing to describe the size of other cables so take caution when ordering cable as to avoid confusion.

Roaming - The ability to move seamlessly from one area of network coverage to another with no loss in connectivity, for example, a laptop staying connected when moved from one room to another.

Router - Device that routes data packets to the intended destination. Each packet is headed by a destination address that the routers use to send the data as they know the IP addresses of devices connected to other routers, working together to determine the fastest route possible. Packets may be disassembled, sent on many different paths and then rebuilt at the other end to increase speed of transfer. Wireless Routers act in a similar way to an Access Point.

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Sector Antenna - The antenna's form gives it a fan-shaped radiation pattern, wide in the horizontal direction and relatively narrow in the vertical direction. Typical antennas used can have around 60° - 150°+ of horizontal beamwidth with a vertical beamwidth not wider than 15° or so. There is usually a downward beam tilt or downtilt so that the base station can more effectively cover its immediate area and not cause RF interference to distant cells. These can be useful in areas such as a very large office room where one sector antenna mounted high, in a corner could provide the whole room with network access.

Side Lobes - As well as a main, principal signal beam being radiated by an antenna, secondary beams that are referred to as side lobes are created. These appear on each side of the main lobe but are much weaker.

Signal to Noise Ratio (SNR) - A measure of the power level of a signal versus the unwanted background noise. A lower ratio means there is more noise relative to signal so a big difference is desirable as it will provide a better quality link. The value stated represents the level of the noise below that of the required signal and so, for example, -80dB would be better than -60dB.

Site Survey - A comprehensive study performed by Wireless Networking Experts to ensure that the planned network service levels will be adequate when deployed. They are usually undertaken by a radio frequency engineer and a systems integrator to determine the optimum placement and location of the wireless devices and are sometimes retested after deployment to ensure that the required levels have been met. Site surveys can also be carried out to detect unwanted, rogue access points that can cause security problems for the network.

Smart Access Points - All entry decisions are made by the access points, in conjunction with a central AAA (RADIUS) server, which maintains the credential database and authorization rules. This implementation can be somewhat expensive to install and maintain because each access point must be individually managed. Also known as “Thick”, “Autonomous” and “Distributed” Access Points.

SMB (SME) - Small & Medium Businesses (Enterprises) are companies whose headcount falls below certain limits. The EU has started to standardize the concept with its current definition categorising companies with fewer than 50 employees as "small" and those with fewer than 250 as "medium".

SoHo - The modern concept of small office/home office refers to the category of business which involves from 1 to 10 workers.

Spread Spectrum - A RF transmission technique that is jamming-resistant and initially devised for military use takes a narrow band signal and spreads it over a broader portion of the radio frequency bandwidth than necessary for interference tolerance and is now a commercial technology.

SSID (Service Set Identifier) - The name of a wireless local area network (WLAN). All wireless devices on a WLAN must employ the same SSID in order to communicate with each other. The SSID on wireless clients can be set either manually, by entering the SSID into the client network settings, or automatically, by leaving the SSID unspecified or blank. A network administrator often uses a public SSID that is set on the access point and broadcast to all wireless devices in range.

Standards - Various groups have produced standards of operation for Wireless Networking devices with allow manufactures to product devices that are compatible with each other by meeting these specifications.

Switch - Network Device that is the central point of connection for computers and other devices in a network and controls the usage as to prevent data collections and ensure optimal network performance so that data can be shared at full transmission speeds. Unlike a hub, a switch only transmits packets to the intended receiving port rather than all ports.

System Operating Margin (SOM) - A way of calculating the difference between the signal strength the receiver's radios are actually receiving as opposed to what it needs for good data recovery. This is calculated by subtracting the receiver sensitivity value (dB) from the Link Budget.

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TDM (Time-Division Multiplexing) - Type of digital multiplexing in which two or more bit streams or signals are transferred apparently simultaneously as sub-channels in one communication channel, but are physically taking turns on the channel.

TDMA (Time-Division Multiple Access) - 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 in which each user transmits in rapid succession, one after the other, each using their own time slot. This allows multiple stations to share the same transmission medium (e.g. radio frequency channel) while using only a part of its channel capacity.

Throughput - The actual data rate that is being experienced at any one time. See “Bandwidth”.

TKIP (Temporal Key Integrity Protocol) - A wireless encryption protocol that periodically changes the encryption key, making it harder to decode.

TPC (Transmission Power Control) - A technique that allows paired radios to adjust themselves to the minimum power levels that still offer a working link. This allows higher gain antennas to be attached to the enable longer distanced links within power level regulations. This is a requirement for all devices operating in Ofcom's 5GHz Band C range.

Transceiver - Device that has both a transmitter and a receiver which are combined within a single unit

Transmit Gain (Tx Gain) - Antenna gain at the transmitter end. See “Gain (Antenna)”.

Transmit Power Output (Tx Power / TPO) - Actual amount of power (usually in mW or dBm) of RF signal energy that a transmitter produces at its output. This is not E.I.R.P as any gain has not been included.

Transmitter - A device that transmits the signal, which is sent to it by devices on the LAN, which is received by the receiving device.

Twisted Pair - Type of wiring in which the forward and return conductors are twisted together for the purposes of cancelling out electromagnetic interference from external sources. UTP cables are an example of twisted pair cabling and are found in many Ethernet networking systems as it is very cheap.

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U

UMTS (Universal Mobile Telecommunications System) - The European, 3G mobile cellular technology for networks based on the GSM standard developed by 3GPP. Supports W-CDMA (UTRA-FDD), UTRA-TDD HCR and TD-SCDMA.

USB - High-performance serial bus communication technology that computers and associated peripheral devices can use to connect to each other. USB 1.0 and 1.1 support 12Mbps throughput with USB 2.0 at 480Mbps and USB 3.0 at 4.8Gbps.

UWB (Ultra Wide Band) - Communication method used in wireless networking to achieve high bandwidth connections with low power utilization. Ultra-wide band wireless radios send short signal pulses over a broad spectrum. For example, a UWB signal centered at 5GHz typically extends across 4 and 6GHz where the wide signal allows high wireless data rates of 480 Mbps up to 1.6 Gbps at distances up to a few meters. At longer distances, UWB data rates drop considerably.

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VoIP (Voice over IP) - VoIP (Voice over Internet Protocol) allows you to make telephone calls over an Internet connection rather than over a conventional telephone network. VoIP converts your voice signal from your telephone into a digital signal that travels over the Internet and converts it back at the other end so you can speak to anyone with a regular phone number.

VSWR (Antenna Voltage Standing Wave Ratio) - This is a ratio figure of the amount of signal that the antenna returns back down the cable that is feeding it. This causes standing waves which can cause interference with the signal resulting in lower power levels. A perfect ratio of 1:1 is impossible to achieve but a figure of 2:1 and below is acceptable.

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W

Wardriving/War Chalking - The process of travelling around looking for wireless access point signals that can be used to get network access and then marking buildings or pavements with chalk to show others where it's possible to access an exposed company’s wireless network.

WDS (Wireless Distribution System) - A method of allow administrators to wirelessly connect access points or Arrays together to form a chain; this is instead of using a wired uplink connection to the network where it is unavailable or costly to implement. It should be noted, however, that the throughput decreases substantially with every repeater added to the chain.

WEP (Wired Equivalent Privacy) - IEEE 802.11 security function that offers frame transmission privacy similar to a wired network. The Wired Equivalent Privacy generates secret shared encryption keys that both source and destination stations can use to alter frame bits to avoid disclosure to eavesdroppers.

Wi-Fi - Refers to WLAN standards based on IEEE 802.11 and its amendments.

Wi-MAX - 3G protocol for data communications on cellular networks. The WiMAX (IEEE 802.16e) standard offers peak data rates of 128Mbps downlink and 56Mbps uplink over 20MHz wide channels whilst the new standard in development, WiMAN-Advanced (802.16m) is targeting the requirements to be fully 4G using 64Q QAM, BPSK and MIMO technologies to reach the 1Gbps rate. It is predicted that in an actual deployment, using 4X2 MIMO in an urban microcell application using a 20 MHz TDD channel, the WiMAN-Advanced system will be able to support 120Mbps downlink and 60Mbps uplink per site concurrently.

Wireless Bridge - See “Ethernet Bridge”.

Wireless Ethernet Compatibility Alliance (WECA) - Wi-Fi certification group that tests and promotes 802.11 standards.

WISP - Service Provider that offers public wireless network services. WISPs typically install Wi-Fi HotSpots in airports, hotels and other public business places. These HotSpots can provide Internet access and local area network (LAN) printing for mobile network devices like laptops, handheld computer and mobile phones.

WLAN - Typically extends an existing wired LAN through the use of wireless signal. WLANs are built by attaching an AP to the wired network where clients communicate with the AP using a wireless network adapter similar in function to a traditional Ethernet adapter.

WPA/WPA2 - Security technology for wireless networks. WPA improves on the authentication and encryption features of WEP. One of the key technologies behind WPA is the Temporal Key Integrity Protocol (TKIP) that addresses the encryption weaknesses of WEP. Another key component of WPA is built-in authentication that WEP does not offer and with this feature, WPA provides roughly comparable security to VPN tunnelling with WEP, with the benefit of easier administration and use.

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Y

Yagi Antenna - Medium gain directional antenna that look similar to a pronged, TV aerial. Flat Panel Antennas have become the popular replacement.

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