E

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EDGE

See Enhanced Data rates for Global Evolution (EDGE).

Equivalent (or effective) Isotropic (or isotropically) Radiated Power (EIRP)

Refers to the technical value that evaluates the strength of receive signals; in other words, the equivalent power of a transmitted signal in terms of an isotropic (omni-directional) radiator. Normally the EIRP equals the product of the transmitter power and the antenna gain (reduced by any coupling losses between the transmitter and antenna).

EIRP

See EIRP.

Electromagnetic Spectrum

See also Spectrum.

See also Electromagnetic Waves.

Electromagnetic Waves

Visible light is made up of electromagnetic waves, vibrations of electric and magnetic fields that propagate through space. In contrast to slow-moving ocean waves to which they are analogous, electromagnetic waves travel at the speed of light: 300 million meters per second, or 669.6 million miles per hour. Furthermore, every electromagnetic wave exhibits a unique frequency and wavelength associated with that frequency. All electromagnetic waves are classified according to their characteristic frequencies, into what is known as the Electromagnetic Spectrum.

Electronic Serial Number (ESN)

Every wireless phone has a unique numbered assigned to it by the manufacturer. That unique number is known as the electronic serial number. According to the Federal Communications Commission, the ESN is to be fixed and unchangeable— a sort of unique fingerprint for each wireless phone.

Embedded

In this book the term "embedded" generally refers to a combination of computer hardware and software, and perhaps additional mechanical parts, designed to perform a dedicated function—Wi-Fi connectivity. In some cases, embedded systems are part of a larger system or product, as in the case of PDAs, laptop/notebook computers, home entertainment centers, etc.

Encoding

In this book, "encoding" refers to a process for conveying or storing electronic data in accordance with a standard format. So-called "line encoding" is the waveform pattern of voltage or current used to represent the is and 0s of a digital signal on a transmission link. Every periodic signal has both a time and frequency domain representation, and both of these can be exploited to encode information into a signal.

Enhanced Data rates for Global Evolution (EDGE)

An intermediate technology that brings second generation GSM closer to third generation capacity for handling data speeds up to 384 Kbps. EDGE uses a new modulation scheme, enabling these higher data throughput speeds using existing GSM infrastructure. EDGE represents the final evolution of data communications within the GSM standard.

ESN

See Electronic Serial Number (ESN).

ESS

See Extended Service Set (ESS).

Ethernet

The IEEE's 802.3 local area network protocol is commonly referred to as "Ethernet." This Ethernet-like standard was published by the IEEE 802.3 Working Group in 1985 and carried the name of "IEEE 802.3 Carrier Sense Multiple Access with Collision Detection Access Method and Physical Layer Specifications." However, the IEEE doesn't refer to 802.3 as "Ethernet," because Ethernet is a specific product trademarked by Xerox whereas 802.3 is a set of standards. The vast majority of wired networks that are in operation today use 802.3's "Ethernet" technology. Standard Ethernet networks use CSMA/CD (Carrier Sense Multiple Access/Collision Detection), which enables the two devices to detect a collision and institute a system for collision avoidance.

ETSI

See European Telecommunications Standards Institute (ETSI).

European Telecommunications Standards Institute (ETSI)

A European non-profit organization whose mission is to produce telecommunication standards for today and for the future, and whose standards are recognized throughout the world.

Extended Service Set (ESS)

Several basic service sets (BSSs) can be joined together to form one logical WLAN segment, which is referred to as an "extended service set." Compare with Infrastructure Basic Service Set.

See also Basic Service Set (BSS).

Extensible Authentication Protocol (EAP)

This 802.1x standard is a Point-to-Point Protocol extension that provides support for additional authentication methods within PPP. This general protocol for authentication also supports multiple authentication methods, such as token cards, Kerberos, one-time passwords, certificates, public key authentication, and smart cards. IEEE 802.1x specifies how EAP should be encapsulated in LAN frames. As such, EAP allows developers to pass security authentication data between RADIUS and the access point and wireless client. EAP has a number of variants, including: EAP MD5, EAP-Tunneled TLS (EAP-TTLS), Lightweight EAP (LEAP), and Protected EAP (PEAP).

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