CWT key terms

A logarithmic unit that expresses absolute RF power relative to one milliwatt, used to describe transmitter output and received signal strength. 0 dBm equals 1 mW, and every 3 dB change doubles or halves the power.

A logarithmic ratio used to compare two power levels. In wireless work it describes gain or loss, such as antenna gain or cable loss, without referencing an absolute reference point like a milliwatt.

The total effective power radiated by an antenna system in a given direction, calculated by adding transmitter output and antenna gain and subtracting cable and connector losses. Regulators cap EIRP for each band and channel.

The measure of how much an antenna concentrates radiated energy in a preferred direction compared with an isotropic radiator, expressed in dBi. Higher gain narrows coverage and extends range along the antenna's main axis.

The angular width of an antenna's radiation pattern, usually stated for the half-power points in the horizontal and vertical planes. It determines coverage shape and how precisely a directional antenna must be aimed.

The orientation of an antenna's electric field, typically vertical or horizontal. Misalignment between transmitting and receiving antennas causes signal loss, so both ends of a link should share the same orientation.

The attenuation a radio signal experiences as it spreads over distance in an unobstructed environment. Loss grows with both distance and frequency, so higher bands fade faster over the same span.

An elliptical volume around the direct line between two antennas where signal energy travels. Obstruction of a significant portion of the first zone weakens the link, so point-to-point paths need vertical clearance.

A clear, unobstructed straight path between two antennas. Visual clearance alone is insufficient because the Fresnel zone must also be mostly clear for reliable links.

The arrival of a transmitted signal at a receiver by several routes due to reflection, diffraction, and scattering. It causes fading and intersymbol interference, and it enables MIMO techniques that exploit separate spatial paths.

A radio technique using multiple transmit and receive antennas to carry independent data streams or improve reliability through spatial multiplexing and diversity. It raises throughput without requiring extra spectrum.

Independent data paths transmitted simultaneously over the same channel using multiple antennas. The number of usable streams depends on the radio chains at each end and on the richness of the RF environment.

A relative value reported by a wireless radio that indicates how strongly a frame was received. Vendors scale it differently, so it is useful for comparisons on one device rather than as absolute power.

The difference in decibels between the wanted signal and the background noise floor at a receiver. Higher values support faster modulation and coding; low values force lower data rates and more retries.

The level of background RF energy in a channel from thermal noise and interference sources. It rises with nearby transmitters and non-Wi-Fi devices, reducing SNR even when signal strength stays constant.

A defined combination of modulation type and forward error correction rate that determines a data rate for a given channel width and stream count. Higher indexes require better SNR.

Combining adjacent channels into a wider one, such as two 20 MHz channels into 40 MHz, to increase throughput. Wider channels carry more data but consume more spectrum and are more prone to interference.

Degradation caused by multiple access points or clients using the same channel in overlapping coverage areas. They must share airtime, which lowers capacity and raises retransmissions.

Interference from a transmitter on a nearby but different channel whose energy spills into the channel in use. Careful channel planning and proper spacing between channels reduce it.

Assigning non-overlapping channels to access points whose coverage areas are close enough to interfere, so the same channel serves distant cells. It is central to capacity planning in dense deployments.

The country or region setting in a wireless device that determines permitted channels, maximum transmit power, and band rules. Mismatched settings between infrastructure and clients cause connectivity failures.

A device that bridges wireless clients onto a wired network, managing association, authentication, and frame forwarding. It may be autonomous with local configuration or centrally managed by a controller.

A design in which a central appliance or cloud service configures, monitors, and coordinates many access points. It simplifies consistent policy and roaming but introduces a dependency on the controller's availability.

A standard method of delivering DC power and data to access points over the same Ethernet cable. Power budgets and standards such as 802.3af, at, and bt determine what each port can support.

The loss of RF signal as it travels along coaxial cable and connectors, measured in decibels and increasing with length and frequency. It is subtracted from transmit power when calculating EIRP.

The human-readable network name broadcast in beacon and probe frames that clients use to select a wireless network. Multiple SSIDs can map to separate VLANs and security policies on one access point.

The MAC address of a specific access point radio serving a basic service set. Clients and analyzers use it to distinguish individual radios that advertise the same network name.

The process by which a client moves its association from one access point to another while keeping its IP address and sessions. Fast transition standards reduce interruption for voice and video.

The protocol that leases IP addresses and related settings such as gateway and DNS servers to clients. Wireless clients rely on it after association, and DHCP failures often appear as limited connectivity.

The final stage of joining a wireless network, in which a client and access point agree on capabilities and the client receives an association identifier. It follows authentication and precedes data exchange.

Assigning each SSID to a specific VLAN so wireless traffic lands in the correct Layer 2 segment and IP subnet. It separates guest, corporate, and device traffic on shared infrastructure.

A certification based on the 802.11i amendment that uses AES with Counter Mode CBC-MAC Protocol for encryption. It exists in personal mode with a shared passphrase and enterprise mode with an authentication server.

A newer certification that strengthens passphrase protection with Simultaneous Authentication of Equals and adds mandatory protected management frames and forward secrecy. Enterprise mode requires protected management frames as well.

A passphrase shared by all users of a personal-mode wireless network. The passphrase derives the pairwise master key, so compromise of one credential exposes the whole network.

A port-based access control framework in which a supplicant, authenticator, and authentication server negotiate access. In wireless enterprise mode it typically uses EAP over RADIUS to issue per-user keys.

A flexible framework for authentication methods used inside 802.1X exchanges. Variants such as EAP-TLS and PEAP differ in whether they use certificates, passwords, or both.

A server protocol that centralizes authentication, authorization, and accounting for network access. Wireless controllers and access points forward 802.1X exchanges to it and receive accept or reject decisions.

A feature from 802.11w that adds cryptographic integrity protection to management frames such as deauthentication and disassociation. It blocks spoofed disconnect attacks and is mandatory in WPA3.

A denial-of-service technique that forges deauthentication frames to force clients off a network. Enabling protected management frames makes such forged frames ineffective.

An unauthorized access point connected to a network, either maliciously or carelessly, that can bypass security controls. Wireless intrusion detection and switch port monitoring help locate and contain it.

A structured assessment of a location's RF conditions and requirements before and after deployment. It determines access point placement, channel plans, and power settings needed for coverage and capacity.

A planning exercise that models coverage using floor plans and attenuation values for walls and materials. It produces a starting design that must later be confirmed with on-site measurements.

An on-site survey performed after installation to confirm that coverage, capacity, and roaming meet the design goals. It uses real measurements to adjust access point placement, channels, and transmit power.

A color-coded visualization of signal strength, SNR, or data rate across a floor plan. It makes weak spots, coverage overlap, and excessive power easy to identify during survey work.