Jason Van Dyk

During the subject Wireless and Mobile Networks there was a series of ‘Quick Quizzes’. So I thought it would be a good study tool to answer these. Now I can’t say for certain I’m 100% correct here, but I thought with all that work put into answering them I might as well post it online.

Anyway, check out the questions and my answers below. If you do notice something is wrong let me know and I’ll try to fix it up. If you haven’t picked up on it yet, my answers are highlighted in the question already.

Lecture 1

1. The automatic connection between various Bluetooth devices creates a(n) piconet, also called a wireless personal area network (WPAN).
2. A WLAN is an extension of a wired LAN, connecting to it through a device called a(n) wireless access point.
3. Wireless Application Protocol version 2.0 (WAP2) provides a standard way to transmit, format, and display Internet data for small wireless devices such as cell phones.
4. Digital Convergence refers to the power of digital devices to combine voice, video, and text processing capabilities, as well as to be connected to business and home networks and the Internet.
5. A(n) Universal Handset is a 1.5-pound device that allows military personnel in the field to communicate through a variety of methods using wireless technologies.
6. Industrial control motes are remote sensors that can connect to a WLAN, then collect data and transmit it to a central location.
7. True or False: Bluetooth and WLAN 802.11b/g devices both operate in the same radio frequency, potentially resulting in interference between such devices.
8. True or False: Wireless devices emit high levels of RF while being used.

Lecture 2

1. The number of times a cycle occurs within one second equals the frequency of a wave.
2. A signal unit that represents two bits is known as a dibit.
3. The height of a carrier wave is known as the amplitude and can be measured in volts (electrical pressure).
4. Phase modulation (PM) changes the starting point of the cycle, while the amplitude and frequency of the carrier remain constant.
5. Phase shift keying (PSK) is a binary modulation technique, similar to phase modulation, in which the transmitter varies the starting point of the wave.
6. Spread spectrum is a technique that takes a narrow band signal and spreads it over a broader portion of the radio frequency band.
7. In FHSS, the sequence of changing frequencies is called the hopping code.
8. A(n) Barker code (or chipping code) is a particular sequence of 1s and 0s that has properties that make it ideal for modulating radio waves, as well as for being detected correctly by the receiver.

Lecture 3

1. A(n) amplifier essentially increases the amplitude of an RF sign.
2. Half-duplex transmission sends data in both directions, but only one way at a time.
3. True or False: Telephone systems use a type of switching known as packet switching.
4. Packet switching requires that the data transmission be broken into small units called packets.
5. A(n) directional antenna radiates the electromagnetic waves in one direction only, and can help reduce or eliminate the effect of multipath distortion if there is a clear line of sight between the two antennas.
6. In the United States, the Federal Communications Commission (FCC) serves as the primary regulatory agency for telecommunications.
7. The radio frequency spectrum is the entire range of all radio frequencies that exist.
8. Adaptive array processing replaces a traditional antenna with an array of antenna elements.

Lecture 4

1. A(n) isotropic radiator is a theoretical perfect sphere that radiates power equally in all directions.
2. Directional antennas are used when you need to transmit a signal in one direction only.
3. In free space loss, RF waves tend to spread away from the source of the signal (the antenna).
4. The length of a single RF sine wave, or the wavelength, is what determines the size of an antenna.
5. Smart antennas “know” where the mobile receiver is, and can track it and focus the RF energy in that particular direction to avoid wasting energy and to prevent interference with other antennas.
6. In most wireless communications applications, one transmitter communicates with several mobile clients. This is called a(n) point-to-multipoint wireless link.
7. The space between two antennas would be more accurately represented by something similar to an ellipse. This elliptical region is called the Fresnel zone.
8. A(n) Spectrum analyzer displays the signal amplitude and frequency, and can also detect interference in a particular frequency or channel.

Lecture 5

1. FIR uses a modulation scheme called  4-pulse position modulation (4-PPM), in which information is conveyed by the position of a pulse within a time slot.
2. At the heart of the Bluetooth RF layer is a single radio transmitter/receiver (transceiver). This single tiny chip is called a Bluetooth radio module.
3. A group of piconets in which connections exist between different piconets is called a(n) scatternet.
4. In sniff mode, a slave device listens to the piconet master at a reduced rate so that it uses less power.
5. The upper ZigBee layers include mechanisms used by the devices to join a network, which is called association.
6. The superframe is a mechanism for managing transmission time in a piconet.
7. Encryption is the process of encoding communications, and ensures that the transmissions cannot be easily intercepted and decoded.
8. Sequential freshness is a security service used by the receiving device that ensures that the same frames will not be transmitted more than once.

Lecture 6

1. The WiMedia Alliance was formed to support the development of any necessary higher-layer protocols and software specifications for 802.15.3 and to perform various other administrative functions.
2. Quality-of-service (QOS) capabilities allow devices to request more channel access time in order to prioritize high-volume, time-sensitive traffic, such as voice stream.
3. The piconet coordinator (PNC) is the device that provides all of the basic communications timing in a piconet.
4. The frame check sequence (FCS) is a 32-bit cyclic redundancy check (CRC) field, a common technique for detecting data transmission errors.
5. Denial-of-service (DoS) attacks flood a Bluetooth device with so many frames that it is unable to communicate.
6. Advanced Encryption Standard (AES) is a symmetric key encryption mechanism introduced by the National Institute of Standards and Technology (NIST) in the United States.
7. Hand-off is the ability of a device to move from one master or PNC to another without getting disconnected from the network in a network that extends beyond the communications range of each device that controls the communications.
8. Spectrum conflict is the potential for technologies using the same frequency bands to interfere with each other to the extent that they sometimes perform poorly when used within close range of each other.

Lecture 7

1. A(n) Mini PCI is a small card that is functionally equivalent to a standard PCI expansion card.
2. The AP will automatically select the highest possible data rate for transmission, depending on the strength and quality of the signal. This process is called dynamic rate selection.
3. The 802.11 standard defines a local area network that provides cable-free data access for clients that are either mobile or in a fixed location at a rate of either 1 or 2 Mbps, using either diffused infrared or RF transmission.
4. Even though it contains data, a 802.11 frame’s size is not measured in bits but in time slots.
5. One type of channel access method is polling. With this method, each computer is sequentially polled, or asked if it wants to transmit.
6. 802.11b standard power management allows the mobile client’s NIC to be off as much as possible to conserve battery life but still not miss out on data transmissions.
7. In the 802.11b standard, management frames are used to set up the initial communications between a client and the AP.
8. The Distributed coordination function interframe space (DIFS) is a standard time interval during which all clients must wait between transmissions of data frames.

Lecture 8

1. IEEE 802.11a uses the Unlicensed National Information Infrastructure (U-NII) band.
2. With an 802.11a WLAN, each AP can use one of 8 available channels.
3. Orthogonal Frequency Division Multiplexing (OFDM) primary function is to split a high-speed digital signal into several slower signals running in parallel.
4. True or False: The IEEE 802.11g standard specifies that it operates in the same frequency band as 802.11b
5. Wireless bridges are designed to connect two wired networks or to extend the range of a WLAN.
6. Authentication is a process that verifies that the client device has permission to access the network.
7. WPA2 is the version of WPA that has been certified by the IEEE to be compatible with IEEE 802.11i.
8. Virtual private networks (VPNs) use an encrypted connection to create a virtual tunnel between two points across a public or corporate network.

Lecture 9

1. A(n) broadband transmission sends multiple signals at different frequencies.
2. Scintillation is defined as the temporal and spatial variations in light intensity caused by atmospheric turbulence.
3. Local multipoint distribution service (LMDS) is a fixed broadband technology that can provide a wide variety of wireless services.
4. True or False: Multichannel multipoint distribution service (MMDS) is a fixed broadband wireless technology that has many similarities to LMDS.
5. A data transmission to or from a single device is called a(n) burst in the 802.16 standard.
6. Latency is the amount of time delay that it takes a packet to travel from source to destination device.
7. Jitter is the maximum delay variation between two consecutive packets over a period of time.
8. RSA is an algorithm developed in 1977 by Ron Rivest, Adi Shamir, and Leonard Adleman.

Lecture 10

1. Short Message Services (SMS) allows for the delivery of short, text-based messages between wireless devices, such as cellular telephones and pagers.
2. The mobile telecommunications switching office (MTSO) is the link between the cellular network and the wired telephone world, and controls all transmitters and base stations in the cellular network.
3. 1G technology is based on the Advanced Mobile Phone Service (AMPS).
4. True or False: W-CDMA adds a packet-switched data channel to a circuit-switched voice channel.
5. A WML document is called a deck that contains one or more blocks, known as cards.
6. The Java programming language was developed by Sun Microsystems as an object-oriented language used for general-purpose business programming, as well as interactive Web sites.
7. The single largest factor limiting the development of 3G is spectrum.
8. Low earth orbit (LEO) satellites circle the Earth at an altitude of 200 to 900 miles (321 to 1,448 kilometers).

Lecture 11

1. One class of active tags is called beacons because they transmit on a periodic basis, without receiving an interrogation from a reader.
2. The mobile telecommunications switching office (MTSO) is the link between the cellular network and the wired telephone world and controls all transmitters and base stations in the cellular network.
3. Sensory tags, as their name indicates, can be equipped with thermal, gas, smoke, pressure, and a variety of other kinds of sensors to monitor and record environmental conditions, liquid volume levels, or attempts to tamper with a product.
4. With EPCs, companies will be able to acquire the manufacturer’s name over the Internet using a service from EPCglobal Inc. called Object Name Service (ONS).
5. HF RFID transmission uses a protocol called slotted terminating adaptive protocol (STAC), in which the tags reply within randomly selected positions or time intervals, referred to as slots.
6. After the destroy password is transmitted by the reader, the tag is permanently disabled and can never be read or written to again.
7. True or False: In hospitals, RFID tags in a patient’s identification bracelet can provide vital information that cannot be easily misplaced.
8. A(n) blocker tag is a device that can be used to simulate the presence of a virtually infinite number of tags.

Lecture 12

1. True or False: Industry experts agree that access to corporate data from almost anywhere is the greatest advantage of wireless technology.
2. Wireless VoIP phones, the telephone handsets that connect to a WLAN’s access point (AP), enable you to use the WLAN for regular telephone calls.
3. Wireless VoIP SOHO routers can be connected to a DSL or cable modem and provide both a WLAN and telephone services through the user’s Internet connection.
4. True or False: The human factor in implementing wireless technology is sometimes a significant obstacle.
5. Upfront costs are costs that are necessary to start a project.
6. A(n) Upfront is a detailed planning document that is sent to potential vendors with precise specifications for the products and services that the organization intends to buy.
7. A(n) wireless application service provider (WASP) can design and create a wireless application to run on a specific range of devices.
8. A(n) help desk is a central point of contact for users who need assistance using technology.