Sample Question Quiz 1

Question 1

What is an SoC and why is it important?

Answer 1

System on a chip is a complete chip containing the necessary components such as GPU, CPU, cache, etc. Uses less power because it includes both hardware and software and has better performance.

Question 2

Which of the following chips sit closer to CPU and why? Northbridge or Southbridge

Answer 2

The Northbridge is closer to CPU because it is directly connected to memory and GPU. The CPU can request data from RAM through northbridge memory controller.

Question 3

What is GPU?

Answer 3

Graphics processing unit which is a specialized type of microprocessor, primary designed for quick image rendering.

Question 4

What is CPU?

Answer 4

Central Processing Unit or the brain of the computer.

Question 5

What is Application Processor (AP)

Answer 5

System designed to support applications running in a mobile operating system environment. Supports memory management, graphics processing, and multimedia encoding.

Question 6

Most smartphones operate on which of the following CPU instruction set? ARM or x86

Answer 6

ARM

Question 7

List at least 3 communication chips in a typical smartphone

Answer 7

NFC, Bluetooth, Wi-Fi, GSM, 4G, 3G

Question 8

Android operating system is based on which of the following? Linux, unix, windows

Answer 8

Linux

Question 9

Which government body regulates wireless communications in the U.S.?

Answer 9

FCC - Federal Communications Commission

Question 10

ETSI.org

Answer 10

European Telecommunications Standards Institute

Question 11

ITU.int

Answer 11

International Telecommunications Union.

Question 12

Name three wireless communication applications that operate in ISM band?

Answer 12

Industrial, scientific, medical radio bands. Google’s Project Loon, microwave oven, WLAN, Bluetooth

Question 13

What is a transceiver?

Answer 13

Transmitter and receiver on the same chip in smartphones

Question 14

RF Basics: Transmitter

Answer 14

Amplifier to strengthen initial signal, oscillator to create carrier wave. Mixer to combine signal. Filter to choose the correct frequency and amplifier to strengthen output signal.

Question 15

What is SNR? why is it an important system level parameter?

Answer 15

Signal to noise ratio. It is important because noise can ruin a signal sent so the lower the ratio, the better

Question 16

What is the difference between the transmission range and detection range?

Answer 16

Transmission range is where devices can communicate with low error rate. Detection range is where devices can detect one another but cannot communicate

Question 17

What is frequency multiplexing

Answer 17

When the frequency spectrum is separated into smaller bands and each user gets one of those band for the whole time. The advantage is no coordination needed but the disadvantage is the inefficient use of bandwidth

Question 18

Which WiFi standard is fundamentally different from all WiFi standards?

Answer 18

Spread spectrum based 802.11b

Question 19

In US, how many non-overlapping channels are there in 2G WiFi standard

Answer 19

3

Question 20

What is WiFi direct

Answer 20

• International Standard by the WiFi Alliance
• WiFi connection without Wireless Access Point
• Protected WiFi setup
• No extra HW required

Question 21

Describe hidden terminal problem?

Answer 21

When two nodes are transmitting to one another and a third node wants to transmit to one of the node but cannot.

Question 22

What is RTS and CTS in CSMA/CA protocol?

Answer 22

RTS and CTS make sure that there are no collision in transmission with different nodes by deferring nodes trying to transmit to nodes that have RTS and CTS NAV.

Question 23

What is RSSI and how is it measured?

Answer 23

Received Signal Strength Indicator

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Question 24

Describe main idea behind location fingerprinting?

Answer 24

Location sensing based on WiFi signal

• Radio map of observed signal strength values from different locations.
• SS values observed at a user mobile device compared to radio map waves using proximity-matching algorithms to infer current user locations

Question 25

What is power islanding?

Answer 25

A location is powered even though an electrical grid power is no longer present

Question 26

What is clock gating?

Answer 26

Reducing dynamic power dissipation. Saves power by adding more logic to a circuit to prune the clock tree.

Question 27

Bluetooth operates in which of the following frequency bands? 2.4GHz, 5GHz, 2.4MHz

Answer 27

2.4GHz

Question 28

Why does Bluetooth use ‘frequency hopping’ method?

Answer 28

• Signal is broadcast over seemingly random series of radio frequencies so eavesdroppers hear only unintelligible blips
• Attempts to jam signal on one frequency succeed only at knocking out a few bits because signal hops from frequency to frequency at fixed intervals.

Question 29

What is in Access Code?

Answer 29

Time synchronization, frequency offset compensation, paging and inquiry, and address of piconet primary

Question 30

What is park mode in Bluetooth?

Answer 30

Admit more than 7 secondary devices into piconet by giving up active member address and getting park member address. Wakes up periodically to check for broadcast to be unmarked.

Question 31

What is scatternet

Answer 31

Interconnection of multiple piconet through bridge nodes

Question 32

How does Bluetooth achieve data rate of 24mbps?

Answer 32

Data is carried over WiFi link

Question 33

What is near-field?

Answer 33

Area from antenna to point where electromagnetic field forms. Inductive coupling

Question 34

What is far-field?

Answer 34

Area some distance from transmitting antenna where electromagnetic wave forms and fully separates from antenna

Question 35

What is the power source of the passive tag?

Answer 35

Reader drives sinusoidal current