Q&A Hero

Q: Each base station is connected to a ________, which serves multiple base stations. A) mobile telecommunications switching office B) public telephone network C) cellular network D) chain of base stations

Q: ________ are useful in city streets in congested areas, along highways, and inside large public buildings. A) Maximum bit rates B) MTSOs C) Microcells D) Control channels

Q: As the mobile units move they pass from cell to cell, which requires transferring of the call from one base transceiver to another. This process is called ________. A) frequency reuse B) a handshake C) equalization D) a handoff

Q: Third generation wireless communication supports ________. A) voice but not multimedia data B) multimedia but not voice C) multimedia and voice D) voice but not video

Q: One of the most widely used models to develop guidelines for cell size was developed by ________. A) Bellman-Ford B) Jacobson C) Dijkstra D) Okumura/Hata

Q: A technique in widespread use in second generation cellular networks is ________. A) TCMP B) CDMA C) 3G D) HTTP

Q: Affecting not only mobile phones in automobiles, but even a mobile phone user walking down an urban street, ________ occurs when there are rapid variations in signal strength. A) selective fading B) nonselective fading C) flat fading D) fast fading

Q: ________ are used to exchange information having to do with setting up and maintaining calls and with establishing a relationship between a mobile unit and the nearest base station. A) Advanced Mobile Phone Services B) Mobile initialization units C) Traffic channels D) Control channels

Q: First generation cellular networks ________. A) were FDDI B) were digital C) were analog D) were based on code division multiple access

Q: A cellular network uses multiple low power ________. A) frequencies B) receivers C) antennas D) transmitters

Q: An important design goal for all three generation systems is to limit channel usage to 5 MHz.

Q: The most widely used second generation CDMA scheme is IS-95.

Q: All first and second generation cellular networks provide encryption.

Q: One unwanted effect of multipath propagation is that multiple copies of a signal may arrive at different phases.

Q: Scattering effects are difficult to predict.

Q: In a mobile environment one of the two antennas is moving relative to the other, therefore the relative location of various obstacles moves also, so as not to hinder transmission.

Q: Mobile radio communication introduces complexities not found in wire communication or in fixed wireless communication.

Q: Only one mobile user unit may be active and communicating with the base station at a time.

Q: Cells in areas of high usage can be split into smaller cells.

Q: Even though cells are sufficiently distant from each other, they still need to be assigned different frequencies to avoid interference or crosstalk.

Q: Cellular technology is the foundation of mobile wireless communications.

Q: Second generation cellular networks were analog.

Q: A wireless cellular system limits the opportunity to use the same frequency for different communications because the signals can interfere with one another even if geographically separated.

Q: A major technical problem for cellular networks is fading.

Q: The area to be covered in a cellular network is divided into cells in a pentagonal tile pattern that provide full coverage of the area andequidistant antennas.

Q: A ________ is a general purpose computer running specialized software that turns it into a smart phone switch. These cost significantly less than traditional circuit switches and can provide more functionality.

Q: A ________ switch is one in which the signal paths are physically separate from one another. Each connection requires the establishment of a physical path through the switch that is dedicated solely to the transfer of signals between the two endpoints.

Q: The ________ level deals with the physical interface between an attached station and the link that attaches that station to the packet switching node.

Q: The function of the ________ is to provide a transparent signal path between any pair of attached devices.

Q: The branches between exchanges are called ________. They carry multiple voice frequency circuits using either FDM or synchronous TDM.

Q: Communication via circuit switching involves three phases: circuit establishment, data transfer and ________.

Q: Each station in a network connects to a node, and the collection of nodes is referred to as a ________ network.

Q: Flexibility, resource sharing, robustness, and responsiveness are all advantages of ________ switching.

Q: The term ________ refers to the logical connection between two stations through the network.

Q: With internal ________ each packet is treated independently and packets intended for the same destination may follow different routes.

Q: A key distinguishing element of packet switching networks is whether the internal operation is datagram or ________.

Q: ________ switching was designed to provide a more efficient facility for bursty data traffic. The attached stations must organize their data into packets for transmission.

Q: Three types of delays are: propagation delay, transmission time and ________ delay.

Q: With ________ virtual circuits a route is defined between two endpoints and all packets for that virtual circuit follow the same route.

Q: ________ switching is used in public telephone networks.

Q: In the ________ approach in packet switching each packet is treated independently with no reference to packets that have gone before. A) datagram B) media gateway C) softswitch D) virtual circuit

Q: A ________ can convert a stream of digitized voice bits into packets. A) softswitch B) node C) LAPF D) virtual circuit

Q: ________ switching involves the partitioning of a lower speed bit stream into pieces that share a higher speed stream with other bit streams. The individual pieces are manipulated by control logic to route data from input to output. A) Packet B) Time division C) Circuit D) Space division

Q: Dynamic use of bandwidth is utilized with ________. A) virtual circuit packet switching and circuit switching B) datagram packet switching and virtual circuit packet switching C) circuit switching and datagram packet switching D) space division switching and circuit switching

Q: A specific preplanned route through the network between two stations is a(n) ________ virtual circuit. A) transport B) direct C) internal D) external

Q: The ________ element represents the functions and hardware needed to connect digital devices such as data processing devices and digital telephones to the network. A) media gateway B) digital switch C) control unit D) network interface

Q: A switching center that directly supports subscribers is known as ________. A) a subscriber loop B) a subscriber center C) a branch exchange D) an end office

Q: In a ________ network, data entering the network from a station are routed to the destination by being switched from node to node. A) communications B) ATM C) switched communication D) packet switching

Q: On a network, the switching devices whose purpose is to provide communication are called ________. These are connected to one another in some topology by transmission links. A) routers B) bridges C) stations D) nodes

Q: The devices attached to a network are referred to as ________. These may be computers, terminals, telephones or other communicating devices. A) entities B) relays C) nodes D) stations

Q: X.25 is the standard protocol used for traditional ________ networks. A) packet switching B) circuit switching C) subscriber loop D) virtual

Q: With packet switching, a station transmits data in small blocks called ________. A) data blocks B) boxes C) channels D) packets

Q: Circuit switching connections ________. A) require manual intervention B) are opaque C) require one time automated set up D) are transparent

Q: With ________ a dedicated path is established between two stations for communication. A) block switching B) packet switching C) circuit switching D) X.25

Q: Circuit switching was developed to handle ________ traffic. A) voice B) A/V C) video D) data

Q: Priorities cannot be used with packet switching.

Q: Analog data must be converted to digital before transmission for packet switching.

Q: Typically standards for packet-switching network interfaces do not define a virtual circuit service.

Q: Circuit switching is a transparent service.

Q: Another well known application of circuit switching is the PBX.

Q: Node-node links are usually multiplexed using either frequency division multiplexing or time division multiplexing.

Q: The packet switching network is a distributed collection of packet switching nodes. Because the nodes are distributed, there is a time delay between a change in status in one portion of the network and knowledge of that change elsewhere.

Q: Circuit switching remains one of the few effective technologies for long distance communications.

Q: Circuit switching and packet switching are traditional approaches to wide area network design.

Q: Each packet contains some portion of the user data plus control information needed for proper functioning of the network.

Q: Circuit switching connections do not appear to attached devices as direct connections.

Q: Elaborate algorithms are used to cope with the time delay and overhead penalties of network operation in a packet switching network.

Q: With circuit switching, switching and transmission resources within the network are reserved for the exclusive use of the circuit for the duration of the connection.

Q: Circuit switching is very efficient in handling digital data.

Q: Circuit switching is the basis for private networks built on leased lines and using on site circuit switches.

Q: In ________ modulation, each signal occupies a distinct frequency band so these signals can be combined by simple addition to produce the composite signal for transmission.

Q: ________ uses multiple carrier signals at different frequencies, sending some of the bits on each channel. The modem sends out test signals on each subchannel to determine the signal-to-noise ratio. The modem then assigns more bits to channels with better signal transmission and less bits to channels with poorer signal transmission.

Q: The disadvantage of using echo cancellation is the need for ________ logic on both ends of the line.

Q: ________ is a modern technology designed to provide high speed digital data transmission over ordinary telephone wire.

Q: An optical transmission interface originally proposed by BellCore and standardized by ANSI is ________. It is intended to provide a specification for taking advantage of the high speed digital transmission capacity of optical fiber.

Q: With ________, the outgoing data rate of the multiplexer, excluding framing bits, is higher than the sum of the minimum instantaneous incoming rates. The extra capacity is used by stuffing extra dummy bits into each incoming signal until its rate is raised to that of a locally generated clock signal.

Q: A form of frequency division multiplexing where the light streaming through the fiber consists of many colors, or wavelengths, each carrying a separate channel of data is ________ multiplexing.

Q: Each modulated signal requires a certain bandwidth centered on its carrier frequency and referred to as a ________.

Q: When the useful bandwidth of the transmission medium exceeds the required bandwidth of signals to be transmitted, ________ multiplexing is possible.

Q: The digital subscriber line combines FDM and ________ technologies.