2.4 Ghz band
The range of radio frequencies from 2.4 to 2.4835 GHz. This band allows for 11 unlicensed channels, and is used by WLANs that follow the popular 802.11b and 802.11g standards.more suseptable to interference than 5Ghz band
Second generation mobile phone service, popular in the 1990s. ____ was the first standard to use digital transmission, and as such, it paved the way for texting and media downloads on mobile devices
Third generation mobile phone service, released in the early 2000s, that specifies throughputs of 384Kbps and packet switching for data (but not voice) communications.
Fourth generation mobile phone service that is characterized by an all-IP, packet-switched network for both data and voice transmission. ____ standards, released in 2008, also specify throughputs of 100Mbps for fast-moving mobile clients, such as those in cars, and 1Gbps for slow-moving mobile clients, such as pedestrians.
5 Ghz band
A range of frequencies that comprises four frequency bands: 5.1 GHz, 5.3 GHz, 5.4 GHz, and 5.8 GHz. It consists of 24 unlicensed bands, each 20 MHz wide. The _______is used by WLANs that follow the 802.11a and 802.11n standards.
The IEEE standard for a wireless networking technique that uses multiple frequency bands in the 5-GHz frequency range and provides a theoretical maximum throughput of 54 Mbps. _______high throughput, compared with 802.11b, is attributable to its use of higher frequencies, its unique method of encoding data, and more available bandwidth.
The IEEE standard for a wireless networking technique that uses DSSS (direct-sequence spread spectrum) signaling in the 2.4-2.4835-GHz frequency range (also called the 2.4-GHz band). _______separates the 2.4-GHz band into 14 overlapping 22-MHz channels and provides a theoretical maximum of 11-Mbps throughput.
The IEEE standard for a wireless networking technique designed to be compatible with 802.11b while using different encoding techniques that allow it to reach a theoretical maximum capacity of 54 Mbps. ______, like 802.11b, uses the 2.4-GHz frequency band.
The IEEE standard for a wireless networking technique that may issue signals in the 2.4 or 5-GHz band and can achieve actual data throughput between 65 and 600 Mbps. It accomplishes this through several means, including MIMO, channel bonding, and frame aggregation. ________is backward compatible with 802.11a, b, and g.
An IEEE standard for wireless MANs. _______networks may use frequencies between 2 and 66 GHz. Their antennas may operate in a line-of-sight or non-line-of-sight manner and cover 50 kilometers (or approximately 30 miles). _______connections can achieve a maximum throughput of 70 Mbps, though actual throughput diminishes as the distance between transceivers increases. Several ______standards exist. Collectively, they are known as WiMAX.
Currently, the most widely implemented version of WiMAX. With _____, IEEE improved the mobility and QoS characteristics of the technology, making it better suited to VoIP and mobile phone users.______is capable of 70 Mbps throughput, but because bandwidth is shared and service providers cap data rates, most users actually experience 1 - 4 Mbps throughput.
Also known as WiMAX 2, the IEEE standard for a version of 802.16 that achieves theoretical throughputs of 330 Mbps with lower latency and better quality for VoIP applications than previous WiMAX versions. _______has been approved as a true 4G technology. Manufacturers expect it to reach throughputs of 1 Gbps in the near future.
A device used on wireless LANs that transmits and receives wireless signals to and from multiple nodes and retransmits them to the rest of the network segment. ______can connect a group of nodes with a network or two networks with each other. They may use directional or omnidirectional antennas.
A method used by wireless stations to detect the presence of an access point. In _____ _____, the station issues a probe to each channel in its frequency range and waits for the access point to respond.
a type of wireless LAN in which communicate directly with each other (rather than using an access point)
In the context of wireless networking, the communication that occurs between a station and an access point to enable the station to connect to the network via that access point
An intermediate connection between subscriber networks and a telecommunications carrier's network.
In the context of wireless networking, a frame issued by an access point to alert other nodes of its existence.
BSSID (Basic service set identifier)
In IEEE terminology, the identifier for a BSS (basic service set)
In the context of 802.11n wireless technology, the combination of two 20-MHz frequency band to create one 40-MHz frequency band that can carry more than twice the amount of data that a single 20-MHz band could. It's recommended for use only in the 5-GHz range, because this band has more available channels and suffers less interference than the 2.4 GHz band.
CSMA/CA (carrier sense multiple access with collision avoidance)
A network access method used on 802.11 wireless networks. In _______, before a node begins to send data it checks the medium. If it detects no transmission activity, it waits a brief, random amount of time, and then sends its transmission. If the node does detect activity, it waits a brief period of time before checking the channel again. ________does not eliminate, but minimizes, the potential for collisions.
in the context of wireless signal propogation the phenomenon that occurs when an electromagnetic wave encounters an obstruction and splits into secondary waves. the second waves continue to propagate in the direction ine which they were split.
A type of antenna that issues wireless signals along a single direction, or path.
DSSS (direct sequence spread spectrum)
A transmission technique in which a signal's bits are distributed over an entire frequency band at once. Each bit is coded so that the receiver can reassemble the original signal upon receiving the bits.
ESS (extended service set)
A group of access points and associated stations (or basic service sets) connected to the same LAN.
ESSID (extended service set identifier)
A special identifier shared by BSSs that belong to the same ESS.
a variation in a signals strength as a result of some of the electromagnetic energy being scattered reflected or diffracted after ebing issued by the transmitter
FHSS (frequency hopping spread spectrum)
A wireless signaling technique in which a signal jumps between several different frequencies within a band in a synchronization pattern known to the channel's receiver and transmitter.
a type of wireless system in which the locations of the transmitter and reciever are static. the transmitting antenna focuses its energy directly toward the receiving antenna
GEO (geosynchronous earth orbit)
refers to a satellite that maintains a constant distance from a point on the equator at every point in its orbit, these satellites are used to provide satellite internet access
the transition that occurs when a cellular network client moves from one antennas coverage area to another
HSPA+ ( high speed packet access plus)
a 3G mobile wireless technology that uses MIMO and sophisticated encoding techniques to achieve a maximum 84 mbps downlink throughput and 11 mbps uplink throughput inits current release. Advances in more efficiently using limited channels and incorporating more antennas in MIMO promise to push the maximum downlink data rate to 336 mbps
A type of WLAN in which stations communicate with an access point and not directly with each other.
A command-line utility for viewing and setting wireless interface parameters on Linux and UNIX workstations.
LOS (line of sight)
A wireless signal or path that travels directly in a straight line from its transmitter to its intended receiver. This type of propagation uses the least amount of energy and results in the reception of the clearest possible signal.
LTE (long term evolution)
A 4G cellular network technology that achieves downlink data rates of up to 1 Gbps and uplink rates up to 500 Mbps. AT&T and Verizon have adopted ____ for their high-speed wireless data networks.
MIMO (multiple input multiple output)
In the context of 802.11n wireless networking, the ability for access points to issue multiple signals to stations, thereby multiplying the signal's strength and increasing their range and data-carrying capacity. Because the signals follow multipath propagation, they must be phase-adjusted when they reach their destination.
type of wireless system in which the reciever can be located anywhere within the transmitters range. This allows the reciever to roam from one place to another while trying to pick up its signal
MSC (mobile switching center)
A carrier's facility that multiple cellular base stations connect to. An ____ might be located inside a telephone company's central office or it might stand alone and connect to the central office via fiber-optic cabling or a microwave link. Equipment at an ____ manages mobile clients, monitoring their location and usage patterns, and switches cellular calls. It also assigns each mobile client an IP address.
The characteristic of wireless signals that follow a number of different paths to their destination (for example, because of reflection, diffraction, and scattering).
A type of wireless transmission in which signals travel over a single frequency or within a specified frequency range.
A type of antenna that issues and receives wireless signals with equal strength and clarity in all directions. This type of antenna is used when many different receivers must be able to pick up the signal, or when the receiver's location is highly mobile.
In the context of wireless networking, the process in which a station listens to several channels within a frequency range for a beacon issued by an access point.
in 802.11 wireless networking, a type of frame issued by a station during active scanning to find nearby access points
the relative strength over a three dimensional area of all the electromagnetic energy an antenna sends and recieves
the geographical area in which signals issued from an antenna or wireless system can be consistently and accurately recieved
the process of a station establishing a connection (or associating) with different access points
the phenomenon that occurs when an electromagnetic wave encounters an obstacle and bounces back toward its source, a wireless signal will bounce off objects whose dimensions are large compared with the signals average wavelength
RTS/CTS (request to send/clear to send)
an exchange in which a wireless station requests the exclusive right to communicate with an access point and the access point confirms that it has granted that request.
the diffusion of a wireless signal that results from hitting an object that has smaller dimensions compared with the signal wavelength. ______also related to the roughness of a surface the wireless signal encounters, the rougher the surface the more likely the signal is to scatter when it hits the surface
In the context of wireless networking, an assessment of client requirements, facility characteristics, and coverage areas to determine an access point arrangement that will ensure reliable wireless connectivity within a given area.
A type of wireless transmission in which lower-level signals are distributed over several frequencies simultaneously. ________transmission is more secure than narrowband.
SSID (service set identifier)
A unique character string used to identify an access point on an 802.11 network.
The equipment on a satellite that receives an uplinked signal from earth, amplifies the signal, modifies its frequency, then retransmits it (in a downlink) to an antenna on earth.
WiMAX (worldwide interoperability for microwave access)
competitor to public access Wi-Fi and cellular phone service. The confusion is that _____ and next generation cellular are both referred to as 4G- ______ is incompatible with both- has an effective range that offers benefits. Considerably more distance covered with _____ over Wi-Fi (802.16a)
A continuum of the electromagnetic waves used for data and voice communication. The _______ _______ (as defined by the FCC, which controls its use) spans frequencies between 9KHz and 300 GHz. each type of wireless service can be associated with one area of the wireless spectrum.