Hello Friends in this article i am gone to share Coursera Course: IoT Communications by University of Illinois at Urbana-Champaign | IoT Communications Coursera Quiz Answers with you..

Enroll Link: IoT Communications

IoT Communications Coursera Quiz Answers

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Also visit: IoT Devices Coursera Quiz Answers

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Week 1 Quiz Answers

Question 1)
Refer to this US Frequency allocation chart (use ctrl+F or the find function in your pdf reader to search). You’re driving in your car on a long road trip and turn the knob of the FM radio to “95.1”.

What electromagnetic frequency is your FM radio tuning to?

• Enter answer here

Question 2)
Two electrical wires are running parallel and close to one another. If you send electrical current across one wire, you see that you induce current flow in the adjacent wire. What type of field does the first wire’s current generate (and that induces current in the adjacent wire)?

• electromagnetic induction

Question 3)
One reason that RF transmitters use low frequencies is that those frequencies are not harmful to humans. Which of the following is another valid reason that RF transmitters may use lower frequencies?

• Lower frequencies are easier to generate and manipulate with low-cost circuits.
• Lower frequencies have higher power, allowing them to “punch through” objects like walls.
• Lower frequencies are easier to generate by Arduino microcontrollers, which run at a lower frequencies.
• Lower frequencies are subject to increased attenuation, making them better for environments where don’t want multiple senders to interfere with each other (e.g., many access points).

Question 4)
You build a typical RF Transmitter that takes digital information and performs modulation, upconversion, and amplification (in that order). What operations will the receiver perform, and in what order?

• modulation -> downconversion -> amplifier
• amplification -> down conversion -> demodulation
• deamplfication -> upconversion -> demodulation

Question 5)
The 3 Little Pigs have advanced to the modern age and instead of worrying about wolves blowing down their houses, they want to make sure their houses have good WiFi reception. Wilbur builds his entire house (including indoor wallS) out of 203 mm concrete, Bacon builds entire his house out of lumber, and Hamlet builds his entire house out of brick.

Assuming that each pig uses the same house architecture, which pig’s house will have the smallest Wifi Signal loss based on their building material?

• Bacon
• Wilbur
• Hamlet

Question 6)
Which of the following is an example when signal attenuation is good?

• Limiting the range of APs in a dense deployment (to decrease the size of contention zones)
• Preventing unauthorized users outside a building from accessing wireless devices inside.
• When the signal needs to be increased in intensity, to reach more users.
• Making the signal broadcast region “narrower”, so it is only broadcast out over a particular angle.

Question 7)
Refer to this constellation diagram:

Which property/properties of radio waves are being modulated in this specific modulation?

• Phase
• Frequency
• Amplitude
• Intensity
• Phase and Amplitude

Question 8)
Big Corn Incorporated has hired you to deploy a fleet of drones that use image recognition to detect pest infestations and other corn crop metrics at one of its massive corn crops in southern Illinois. As part of your deployment you will construct a base station that relays data from drones to a satellite in low earth orbit.

Which type of antenna is most appropriate for your base station to relay data to the satellite?

• Omnidirectional
• Horn
• Parabolic
• Planar inverted F antenna (PIFA)

Question 9)
Big Brother Day Care has hired you to construct an IoT platform for tracking the kids. Each child will have a wireless sensor tag taped to their backs which will monitor their behavior and beep if they are doing something naughty. There will be a set of access points deployed across the facility, and wireless transmitters on the devices will send communications wirelessly to them.

Which type of antenna is most appropriate for kid tags to communicate to the access points?

• Parabolic
• Yagi
• Omnidirectional
• Horn
• Planar inverted F antenna (PIFA)

Question 10)
Sheryl and Andrew set up a transmitter and receiver between their houses so they can talk to each other. The transmitter and receiver have a clear line of sight, but when a tall semi drives between their houses, the semi obstructs some of the signal even though line of sight between the antennae is never broken.

• Andrew and Sheryl bought faulty antennas.
• Why are the semis partially obstructing the RF signal?
• The semis are entering the Fresnel Zone of the antenna.
• The semi is causing diffraction, causing part of the signal to be pulled down towards the ground.

Question 11)
Consider the modulation scheme used in the following figure:

Which RF modulation scheme is being used in the diagram above?

• Enter answer here

Question 12)
What determines the spacing between wires forming the grid of a parabolic antenna (or decision to use a solid material in place of a grid)?

• Frequency/wavelength of the broadcast signal.
• Phase of the broadcast signal.
• Amplitude/intensity of the broadcast signal.
• Environmental factors – e.g., having a grid, wind can just blow through.
• Sun protection.

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Week 2 Quiz Answers

Question 1)
What is the “hidden terminal” problem, in the context of wireless communications?

• When a sender A attempts to communication with destination D, but A is outside D’s radio range.
• When senders A and B attempt to communicate with a destination D, but D is outside both A’s and B’s radio range.
• When a sender A communicates with a destination D, but its communications collide with a node B, where B is within D’s radio range but not within A’s.
• When a sender A communicates with a destination D, but its communications collide with a node B, where B is within both A’s and D’s radio range.

Question 2)
True or False: Collision Detection is better than Collision Avoidance for wireless networking.

• True
• False

Question 3)
What is the primary goal of a MAC protocol?

• To provide high-level APIs like remote file access.
• To control the physical process of transmitting bits.
• To provide functions like congestion control and retransmission.
• Control how devices gain network access to a medium and acquire permission to transmit data.

Question 4)
Why is Collision Detection (CD) not often used for Wireless MAC Protocols?

• Hidden terminal problem.
• Wireless devices are often limited in battery capacity and power.
• Wireless devices often transmit only occasionally, as opposed to sending continuously at high data rates.
• Clock drift.

Question 5)
Assume that no CA/CD is being performed in a wireless network with 2 nodes and one AP. At time t = 0, node N1 starts transmitting a message over the span of 5 seconds. At time t = 2, node N2 starts transmitting a message over the span of 5 seconds using the same frequency N1 is using and to the same AP.

Which message(s) will the AP have successfully received (received the whole message) after t = 7?

• N1’s message will be received.
• N2’s message will be received.
• Neither N1’s nor N2’s message will be received.
• Both N1’s and N2’s message will be received.

Question 6)
Daniel defines a new protocol to save power in his IoT network. All devices in Daniel’s network will go to sleep for 30 seconds after 30 seconds of being awake. This process will repeat, forever. Nodes will rely solely on their local clocks to know when to wake and sleep.

What is one problem with Daniel’s protocol?

• Clock drift.
• There are no beacons.
• Hidden terminal problem.
• Nothing – the scheme will work as described.

Question 7)
Rushi defines a new power saving protocol with a Beacon that determines superframes as discussed in lecture. Within a super frame, nodes sleep for 0.1 nanoseconds and are awake for 0.05 nanoseconds. He champions this protocol because nodes are asleep ⅔ of the time and the response time between sleep periods is short. What is one problem with Rushi’s protocol?

• Warm-up time.
• Beacons would collide, preventing them from being received.
• There is no issue with the protocol.
• Only 1/3 of battery lifetime is conserved.
• The nodes should sleep for 0.05 nanoseconds to keep the sleep and awake durations the same.
• Hidden terminal problem.

Question 8)
Imagine that a device D wants to transmit to an AP. D waits until all devices that are visible to D are not transmitting before D sends its data to the AP. Does D’s strategy prevent collisions at the AP?

• Yes
• No

Question 9)
Consider the following time-series diagram, showing two nodes using Long Preamble Emulation (LP):
At what time would node B transmit its data?

• Time A
• Time B
• Time C

Question 10)
You want to choose a Wireless MAC that minimizes the use of the wireless channels when there is no application data to send. Which of the following Wireless MACs is the best choice for that task:

• Beacon Tracking (BT)
• Long Preamble Emulation (LPE)
• Global Synchronization (GS)

Question 11)
True or False: Non-Beacon Mode algorithms let nodes autonomously discover each other’s wake times on demand.

• True
• False

Question 12)
You are using Long Preamble Emulation (LPE) as a Wireless MAC, and you have the wakeup interval set for twi seconds on all nodes. Node A wants to send data for Node B. Assume there are no node failures and that A’s and B’s intervals overlap. What is the minimum number of seconds that node A has to send write requests before it can be sure that B received the messages. Note that B only ACKs that it has received all the data in this question.

Note the wi is subscript font
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Answer: twi
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Question 13)
True or False: protocols that use beacons and a Coordinator can only have one Coordinator in their network.

• True
• False

Question 14)
What is the standard number IEEE assigned for the IoT wireless MACs discussed in class?

• 802.15.4

Question 15)
True or False: LLDP uses IP addresses to discover neighbors in its subnet.

• True
• False

Question 16)
You walk into your dentist’s office, open up your laptop, and want to connect my laptop to the internet. You click on the ‘Wi-fi’ tab and click on “HappyTeethGuestWireless” to connect to the internet. What is “HappyTeethGuestWireless” an identifier for?

• The IP address of my laptop
• The SSID that all APs at your dentist’s office
• The MAC address of the AP in the dentist’s office you connected to

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Week 3 Quiz Answers

Question 1)
What IoT protocol would be most appropriate for having a heart monitor communicate with a smartphone in the person’s pocket every 2 minutes?

• LTE-M
• Wi-Fi
• Bluetooth LE

Question 2)
True or False: The Zigbee Protocol is entirely in layers 1 and 2.

• True
• False

Question 3)
With link state update propagation, what is the contents of some node n’s topological map before performing link-state advertisements?

• A complete map of the network
• A map of all of n’s neighbors
• Nothing, it is empty

Question 4)
True or False: Proactive routing determines routes as needed.

• True
• False

Question 5)
Imagine a topology where F is connected to G and G is connected to H. There are no other nodes or edges in the network graph. In distance vector routing, what will G tell H about G’s connection to F?

• “G has a link to F”
• “G has no way to reach F”
• “G is one hop away from F”
• H will receive a source-route to F with the following sequence of nodes: H->G->F.

Question 6)
Link-state uses ____ algorithm and Distance Vector uses ____ algorithm.

• (Dijkstra’s, Bellman-Ford)
• (Bellman-Ford, Bellman-Ford)
• (Tarjan’s, Dijkstra’s)
• (Bellman-Ford, Dijkstra’s)

Question 7)
OLSR is an optimized version of which class of traditional routing algorithms?

• Link-State
• OSPF
• Dijkstra’s
• BGP
• Distance vector

Question 8)
What does OLSR optimize compared to “vanilla” link-state?

• Both of the options are correct
• Neither of the options are correct
• The size of the topological maps at each node
• The number of total broadcasts required for all nodes to have a complete topological map of the network

Question 9)
True or False: OLSR selects the optimal number of nodes to be MPRs and forward advertisements.

• True
• False

Question 10)
True or False: A route discovered by Dynamic Source Routing may not be the shortest possible route from a source node to a destination node within the network.

• True
• False

Question 11)
Which of the following routing protocols embeds the path within the actual data packet when it is sent?

• OLSR
• DSR
• AODV
• Link-state
• Distance-Vector

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Week 4 Quiz Answers

Question 1)
You are using hierarchical addressing and tree routing. What happens if a node needs to forward a packet to a destination that is not within the ranges of its children?

• Fails silently
• Sends packet to its sibling
• Sends packet to its parent
• Sends packet to its children, and ask that children figure it out

Question 2)
In naive geographic routing, how does each node determine which node to forward a packet to?

• Choose the neighbor with geographic coordinates most similar to the current hop.
• Randomly.
• Chose the neighbor with geographic coordinates sharing the maximum number of digits with the destination.
• Choose the one-hop neighbor with the smallest remaining distance to the destination.
• Choose the one-hop neighbor that gives the optimal path to the destination, leveraging the global view of the network.

Question 3)
In IoT networks, we can assume that the network consists of one connected component.

• True
• False

Question 4)
Which type of routing is characterized by randomly forwarding messages to neighbors and has a high fault-tolerance?

• OLSR
• AODV
• Gossip
• Hierarchical

Question 5)
What are some advantages of topology-dependent addressing?

• Easier to keep addresses up to date, as they are assigned based on the topology.
• Routing gets easier, as you can tell where destinations are based on their addresses.
• Tells you information about the node’s geographic position, as it’s encoded in the topology-dependent address.

Question 6)
What effect does “rumor mongering” have on information propagation?

• Dealing with packet loss, by re-broadcasting information repeatedly.
• Slowing information propagation.
• Speeds up propagation, by making new information each more nodes.
• Blocking false information, by comparing information across nodes.
• Reduces inconsistency, by deleting stale information.

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Week 1 Honors Checklist Quiz Answers

Question 1)
Check what applies to you (pick all that apply).

• I have finished the lab assignment for week 1 honors section.
• I have posted the discussion forum entry for week 1 honors section and responded to at least two entries of my peers.
• I certify that I have completed these tasks to my own and best efforts, and that I am able to explain what I did.

Question 2)
If you did the lab, you should know the answer to this question. In the lab, what are the two protocols that are used for the device’s connectivity?

• 5G and Laserlink
• Bluetooth and WiFi
• GPS and Radar
• LiDAR and Quantum Interference

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Week 2 Honors Checklist Quiz Answers

Question 1)
Check what applies to you (pick all that apply).

• I have finished the lab assignment for week 2 honors section.
• I have posted the discussion forum entry for week 2 honors section and responded to at least two entries of my peers.
• I certify that I have completed these tasks to my own and best efforts, and that I am able to explain what I did.

Question 2)
If you did the lab, you should know the answer to this question. In the lab, what javascript library is used?

• Electron
• Bootstrap
• React
• D3

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Week 3 Honors Checklist Quiz Answers

Question 1)
Check what applies to you (pick all that apply).

• I have finished the lab assignment for week 3 honors section.
• I have posted the discussion forum entry for week 3 honors section and responded to at least two entries of my peers.
• I certify that I have completed these tasks to my own and best efforts, and that I am able to explain what I did.

Question 2)
If you did the lab, you should know the answer to this question. In this step of the lab, we are building a frontend using a JS-framework. Which one?

• Vue
• React
• Electron
• D3

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Week 4 Honors Checklist Quiz Answers

Question 1)
Check what applies to you (pick all that apply).

• I have finished all lab assignments in the course.
• I have posted the discussion forum entry for week 4 honors section and responded to at least two entries of my peers.
• I certify that I have completed these tasks to my own and best efforts, and that I am able to explain what I did.

Question 2)
If you did the lab, you should know the answer to this question. Which method is mentioned in the part “Where to go from here?”

• Antipolar Virtualization
• Swarm Intelligence
• Push Notifications
• Distributed Sensing