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Wireless Solutions
You have the questions, we have the answers.  The terms listed here are common wireless terms. This page provides a brief definition of these terms and how they relate to products designed for wireless applications.

Wireless Glossary
Index: # A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
  • 2G - Second generation of mobile wireless communications systems.
  • 2.4GHz - Currently the only world-wide frequency standard. This is one of the unlicensed bands reserved for ISM (Industrial, Scientific and Medical) Use. Current technologies that use this band include 802.11 (Wi-Fi), Bluetooth, and ZigBee. Devices in this band use a spread spectrum technique for transmitting and receiving signals.
  • 3G - Third generation of mobile wireless communications systems, allowing for high speed internet, audio/video streaming.
  • 3GSM - See UMTS
  • 315MHz - A U.S. and Canada wide frequency standard. Used for Radio telemetry, remote control.
  • 418MHz - A U.S. and Canada wide frequency standard. Used for Radio telemetry, remote control.
  • 433MHz - A European wide frequency standard. Used for Radio telemetry, remote control.
  • 434MHz - A European wide frequency standard. Used for Radio telemetry, remote control.
  • 458MHz - A European wide frequency standard. Used for Radio telemetry, remote control.
  • 802.11b - The standard on which most WLANs are currently based, allowing data rates up to 11 Mbps in the 2.4 GHz ISM radio frequency band. See also 802.11.
  • 802.11g - A WLAN standard with data rates to 54 Mbps in the 2.4 GHz ISM radio frequency band using OFDM (Orthogonal Frequency Division Multiplexing) technology.
  • 802.15.4 - A standard which specifies the physical layer and media access control for low-rate wireless personal area networks.
  • 868MHz - A European frequency standard.
  • A/D - Analog-to-digital
  • AM - Amplitude modulation - Modulation using amplitude variation in proportion to the amplitude of the modulating signal.
  • Antenna directivity - This is the relative gain of the main beam of an antenna pattern to a reference antenna, usually an isotropic or standard dipole.
  • Antenna gain - Ability of an antenna to receive signals in any given direction. The higher gain an antenna, the more directive it is. This will be apparent in the pattern of the antenna as it will show increased sensitivity in one or more directions.
  • Application layer - The top layer of the OSI seven layer model. This layer handles issues like network transparency, resource allocation and problem partitioning. The application layer is concerned with the user's view of the network.
  • ASK - Amplitude Shift Keying - a form of modulation that represents digital data as variations in the amplitude of a carrier wave.
  • Attenuation - A decrease in signal magnitude between two points. These points may be along a radio path, transmission line or other device.
  • Bandwidth - The speed at which data travels across a network connection and is typically specified in kilobits per second (kbps) or megabits per second (Mbps).
  • Baud - Unit of measure for serial communication speeds.
  • Bluetooth - A short-range radio technology meant to simplify communication between devices. Bluetooth operates in the 2.4GHz ISM radio frequency band, and is an interoperable standard based on application profiles, which are meant to allow devices with the same profile to communicate. Uses FHSS (Frequency Hopping Spread Spectrum), which allows it to hop frequencies, which allows for interference avoidance and security.
  • BPSK - Binary Phase Shift Keying - A type of phase modulation using 2 distinct carrier phases to signal ones and zeros.
  • Broadband - A high-speed phone and Internet connection which allows you to browse the Internet and use your home phone at the same time.
  • Broadcast - A transmission sent to many recipients on a network regardless of the node address of the device. Most radio transmissions are broadcasts and can require the use of encryption to protect privacy.
  • C/N - Carrier-to-noise. See carrier-to-noise ratio.
  • Carrier - An RF signal that has an information signal superimposed on it through modulation. Also called a carrier signal.
  • Carrier-to-noise ratio - The ratio of power in an RF carrier to the noise power in the channel.
  • CDMA - Code Division Multiple Access is a form of multiplexing pioneered by Qualcomm to develop a Second Generation digital cellular telephony system that became very popular in the Americas, South Korea and other countries.
  • Codec - Coder decoder - chip that converts digital signals to analog and from analog signals to digital.
  • Counterpoise - Counterbalance; bring into balance by means of an opposing weight or force.
  • CRC - Cyclic redundancy check - An error-detection scheme that (a) uses parity bits generated by polynomial encoding of digital signals, (b) appends those parity bits to the digital signal, and (c) uses decoding algorithms that detect errors in the received digital signal.
  • Crosstalk - Interference caused by the mixing of two frequencies that are traveling on different channels.
  • dB - deciBel - A technique for expressing voltage, power, gain, loss or frequency in logarithmic form against a reference. Typical references include volts, watts or Hz. DeciBels are calculated using the expression: dB = 10*log(x/y).
  • dBc - deciBels referenced to the carrier - A technique for expressing a power measurement in logarithmic form using the carrier power as a reference.
  • dBd - deciBels referenced to a dipole antenna - A technique for expressing a power gain measurement in logarithmic form using a standard dipole antenna as a reference.
  • dBi - deciBels referenced to an isotropic antenna - A technique for expressing a power gain measurement in logarithmic form using a theoretical isotropic antenna as a reference.
  • dBm - deciBels referenced to a milliWatt - A technique for expressing a power measurement in logarithmic form using 1 mW as a reference.
  • Dipole - A pair of magnetic poles
  • DQPSK - Differential Quadrature Phase Shift Keying - QPSK modulation using differential encoding of the digital information stream.
  • DSSS - Direct-sequence spread spectrum - A modulation technique which a signal takes up more bandwidth than the information signal that is being modulated.
  • EDGE - Enhanced Data GSM Environment. A faster version of GSM. Allows data rates up to 384Kbps.
  • Encryption - A cryptographic technique utilizing a digital key to scramble and hence "lock" data in such a manner that it cannot be descrambled and decoded without the key.
  • FCC - Federal Communications Commission - An independent U.S. government agency established by the communications Act of 1934 to regulate the broadcasting industry. The commission later assumed authority over cable. The FCC is administered by seven commissioners and reports to Congress. The FCC assigns broadcasting frequencies, licenses stations, and oversees interstate communications.
  • FHSS - Frequency-hopping spread spectrum - A method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using pseudorandom sequence known to both transmitter and receiver.
  • FM - Frequency modulation - conveys information over a carrier wave by varying its frequency.
  • Fresnel zone - Path between a transmitting device and a receiving device in free air. The Fresnel Zone is smallest at the antennas and widest in the middle of the antennas.
  • FSK - Frequency Shift Keying - A form of modulation using multiple carrier frequencies to carry the digital information. The most common is the two frequency FSK system using the two frequencies to carry the binary ones and zeros.
  • Full duplex - Full bidirectional communication, full communication in two directions.
  • GFSK - Gaussian Frequency-Shift Keying - type of Frequency Shift Keying modulation that utilizes a Gaussian filter to smooth positive/negative frequency deviations, which represent a binary 1 or 0.
  • GHz - Gigahertz, unit of frequency equal to 1,000MHz.
  • GPRS - Short for General Packet Radio Service, a standard for wireless communications which runs at speeds up to 115KB/s, compared with current GSM (Global System for Mobile Communications) systems 9.6KB/s.
  • GPS - Global Positioning System. It is a Medium Earth Orbit satellite navigational system formed by 24 satellites orbiting the earth and their corresponding receivers on the earth. A GPS device uses a series of satellite location data to calculate its position on earth.
  • Ground plane antenna - A type of antenna consisting of a defined radiating element, usually a 1/4 wave rod or wire, and a metallic ground plane. Commercial ground plane antennas often use a number of 1/4 wave or longer radial rods as the ground plane; the rods may be tilted downwards into a cone to improve the antenna pattern.
  • GSM - Global System for Mobile Communications, a widely-adopted digital cellular phone system. Although standardized in Europe, GSM is not only a European standard. GSM networks operate at four different radio frequencies; most use the 900 MHz or 1800 MHz bands, but some countries in the Americas use 850 MHz and 1900 MHz bands. Can operate at data rates up to 9.6KB/s.
  • Half duplex - communications which can transfer information in only one direction at a time.
  • Harmonic distortion - Acoustic distortion characterized by unwanted changes between input and output at a given frequency.
  • Helical Antenna - A coiled wire instead of a straight wire. It is used to make the antenna physically smaller while electrically staying the same length.
  • Hz - Hertz, a measurement of frequency, one Hertz equals one cycle per second.
  • ISM - Term for use of products in one of the Industrial, Scientific, and Medical frequency bands available in the wireless spectrum. These bands are also known as License-free, which means that the operator of the wireless equipment does not need to have a license to operate the device. The product is still required to be tested and certified for use in the region of operation. ISM bands vary by region, but popular bands operate at 2.45GHz worldwide, 915MHz in the US, 868 MHz in the EU, and various others by region.
  • kHz - Kilohertz, unit of frequency equal to 1,000Hz.
  • Link - The radio connection between a transmitter and a receiver.
  • Link budget - A calculation involving the gain and loss factors associated with the antennas, transmitters, transmission lines and propagation environment used to determine the maximum distance at which a transmitter and receiver can successfully operate.
  • LNA - Low Noise Amplifier - A special amplifier that boosts a small signal while contributing a negligible amount of noise.
  • Log periodic antenna - A broadband, multi-element, unidirectional, narrow-beam antenna that has impedance and radiation characteristics that are regularly repetitive as a logarithmic function of the excitation frequency.
  • LOS - Line of sight - A description of an unobstructed radio path or link between the transmitting and receiving antennas of a communications system.
  • MHz - Megahertz, unit of frequency equal to 1,000,000Hz.
  • Mifare - A contactless smartcard technology used in RFID applications. The technology is owned by Philips Austria GmbH.
  • MMS - Multimedia Messaging Services allows pictures and video to be sent to other MMS devices.
  • Modem - Modulator Demodulator - device which allows the transfer of data through a telephone line, cable line, or wirelessly from one computer to another.
  • MSK - Minimum shift keying - type of continuous-phase frequency-shift keying that was developed in the late 1960s. Similar to OQPSK, MSK is encoded with bits alternating between quaternary components, with the Q component delayed by half the symbol period. However, instead of square pulses as OQPSK uses, MSK encodes each bit as a half sinusoid. This results in a constant-modulus signal, which reduces problems caused by non-linear distortion. In addition to being viewed as related to OQPSK, MSK can also be viewed as a continuous phase frequency shift keyed (CPFSK) signal with a frequency separation of one-half the bit rate.
  • Multicast - A network addressing method for the delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once, creating copies only when the links to the multiple destinations split.
  • Narrow band - A narrowband radio operates over a smaller frequency spread or band. The receiver is less exposed to external RF interference and by design has an increased sensitivity to it’s target band.
  • Network layer - The third lowest layer in the OSI seven layer model. The network layer determines routing of packets of data from sender to receiver via the data link layer and is used by the transport layer.
  • Node - A point of connection in a network. A node is often a device on the network that can process a transmission or forward it to another node. OOK - On off Keying - type of modulation that represents digital data as the presence or absence of a carrier wave. In its simplest form, the presence of a carrier for a specific duration represents a binary one, while its absence for the same duration represents a binary zero.
  • Phase modulation - Modulation of the phase of the carrier wave.
  • Physical layer - Layer one, the lowest layer, in the OSI seven layer model, concerning electrical and mechanical connections to the network. The physical layer is used by the data link layer.
  • PSK - Phase shift keying - A broad classification of modulation techniques where the information to be transmitted is contained in the phase of the carrier wave.
  • QPSK - Quadrature Phase Shift Keying - PSK but uses 4 points on the constellation diagram.
  • Reflection - Act of casting back a mirror image; act of sending back energy from a surface; state of being reflected.
  • Repeater - Receives radio signals from the base station. They are then amplified and re-transmitted to areas where radio shadow occurs. Repeaters also work in the opposite direction, i.e. receiving radio signals from mobile telephones, then amplifying and re-transmitting them to the base station.
  • RFID - Short for Radio Frequency Identification, the energy emitted by the RFID Tag reader is used by the Tag to re-transmit data stored on a piece of memory, the energy can also be used to write data to the tag.
  • RFID tag - See Transponder.
  • Router - A data switch that handles connections between different networks. A router identifies the addresses on data passing through the switch, determines which route the transmission should take and collects data in so-called packets which are then sent to their destinations.
  • RSSI - Receive signal strength indicator - A value which indicates the approximate amount of received signal present at the input of the receiver.
  • RTS - Request to send - A signal to the sending modem that the terminal is ready to transmit; part of modem handshaking.
  • SIM - Subscriber Identity Module and commonly known as a SIM card. The SIM is a one of the key features of GSM and later phone networks. A SIM card allows a user to keep his/her subscriber information when switching handsets as it is a form of removable media.
  • SMS - Short Message Service or text message enables short text-only messages of up to 160 characters in length over the mobile phone network.
  • Telemetry - Telemetry is a technology that allows the remote measurement and transmission of data to the operator and is derived from the Greek words "tele" = remote, and "metron" = measure.
  • Third order intermodulation - TOI - One of several types of intermodulation products that can be created in electronic circuits. In this case, the second harmonic of an input frequency mixes with a second input frequency to yield a third output frequency which is not present at the input.
  • Time slot - Period of time set aside for broadcasting.
  • Transceiver - A transmitter and receiver contained in one package. A 2-way radio or cell phone is an example of a transceiver.
  • Transponder - In RFID it is the device that automatically transmits when it receives a signal.
  • UMTS - Universal Mobile Telecommunications System is one of several third-generation (3G) mobile phone technologies. It uses W-CDMA as the underlying standard, is standardized by the 3GPP, and is the European/Japanese answer to the ITU IMT-2000 requirements for 3G Cellular radio systems. To differentiate UMTS from competing network technologies, UMTS is sometimes marketed as 3GSM, emphasizing the combination of the 3G nature of the technology and the GSM standard which it was designed to succeed.
  • Unicast - The sending of information packets to a single destination.
  • W-LAN - Short for Wireless Local Area Network. Based on IEEE 802.11b. Includes WiFi, WiMAX protocols.
  • WAP - The Wireless Application Protocol is a free, global protocol that allows specially tailored Internet pages to be received and displayed on the screen of WAP-enabled mobile phones, PDAs and other handheld devices.
  • Wavelength - Length of a wave.
  • Wi-Fi - Stands for Wireless Fidelity and refers to certain types of wireless local area network (WLAN). The term was created by the Wi-Fi Alliance, which oversees tests that certify product interoperability. A product that has passed these tests can be labeled "Wi-Fi certified" (a registered trademark).
  • Yagi antenna - A linear end-fire antenna, consisting of three or more half-wave elements (one driven, one reflector, and one or more directors). Note 1: A Yagi antenna offers very high directivity and gain.
  • ZigBee - ZigBee is a low data rate, two-way standard for industrial and domestic automation networks. It uses small very low-power devices to connect together to form a wireless control web. The standard supports 2.4GHz unlicensed radio bands.