Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Kommunikasjon - Tjenester og nett > Chapter 7: Wireless and Mobile Networks > Flashcards

Chapter 7: Wireless and Mobile Networks Flashcards

1
Q

What are the two important challenges faced by wireless & mobile networks?

A

Wireless and mobility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which element of a wireless network is described below?
Used to connect mobile(s) to base station, also used as a backbone link. Uses multiple access protocol coordinates for link access. Has various transmission rate and distances & frequency bands.

A

Wireless link

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which element of a wireless network is described below?
Runs applications. May be stationary (non-mobile) or mobile. E.g. laptop, smartphone, …

A

Wireless host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which element of a wireless network is described below?
Typically connected to wires network and responsible for relay

A

Base station

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give the definition:
Sending packets between wired networks & wireless host(s) in the base station area

A

Relay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which mode of a wireless network is this?
Base station connects mobiles into wired network

A

Infrastructure mode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the technique that a wireless network employs when a mobile changes base station providing connection into the wired network called?

A

Handoff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which mode of a wireless network is this?
The mode where there are no base stations. Nodes can only transmit to other nodes within link coverage and nodes organize themselves into a network - route among themselves

A

Ad hoc mode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which type of wireless network is described below?
Host connects to base station which connected to larger wired network.

A

Infrastructure mode with single-hop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which type of wireless network is described below?
No base station & no connection to larger wired network

A

No infrastructure mode with single hop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which type of wireless network is described below?
The host has to relay through several wireless nodes to connect to a larger network

A

Infrastructure mode with multiple hosts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which type of wireless network is described below?
No base station & no connection to larger wired network. May have to relay to reach other / a given wireless node

A

No-infrastructure mode with multiple hosts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which sort of link has the following characteristics?
Decreased signal strength
Interference from other sources
Multipath propagation

A

Wireless link

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give the definition:
Relative measure of the strength of a received signal & the noise (measured in dB)

A

Signal-to-Noise Ratio (SNR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Is SNR larger or smaller when it’s easier to extract a signal from noise and the BER is lower?

A

Larger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is the likelihood of noise overpowering a signal decreasing a result of increasing or decreasing SNR?

A

Increasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Is the reduction of BER a result of increasing or decreasing SNR?

A

Increasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Is a receiver being able to more accurately interpret the transmitted bits a result of increasing or decreasing SNR?

A

Increasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

For a given SNR, will a modulation technique with a higher bit transmission rate have a higher or lower BER?

A

Higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which problem with wireless networks is described below?
1. B and A hear each other
2. B and C hear each other
3. A and C can’t hear each other –> A and C are unaware of their interference at B

A

Hidden terminal problem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which problem with wireless networks is described below?
1. B and A hear each other
2. B and C hear each other
3. A and C can’t hear each other interfering at B resulting in decreasing signal strength for A and C

A

Signal attenuation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What sort of CSMA do all IEEE 802.11 wireless LANs use for multiple access?

A

CSMA/CA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What two network versions do 802.11 wireless LANs have?

A

Base-station & ad hoc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The 802.11 LAN architecture consists of wireless hosts that communicate with…

A

Access Points / Base stations

25
What part of the 802.11 LAN architecture contains the following in infrastructure mode: - Wireless hosts - Access Points - Ad hoc mode: with hosts only
Basic Service Set (BSS)
26
Give the definition: Frames used in 802.11 LANs that include an AP's SSID & MAC address
Beacon frames
27
What sort of scanning by 802.11 is described below? 1. Beacon frames sent from APs 2. Association Request frame sent: H1 to selected AP 3. Association Response frame sent: selected AP to H1
Passive scanning
28
What sort of scanning by 802.11 is described below? 1. Probe Request frame broadcast from H1 2. Probe Response frames sent from APs 3. Association Request frame sent: H1 to selected AP 4. Association Response frame sent from selected AP to H1
Active scanning
29
Does 802.11 have collision detection?
No
30
What 802.11 collision avoidance technique is described below? 1. Sender first transmits small Request-To-Send (RTS) packet to BS using CSMA 2. BS broadcasts Clear-To-Send (CTS) in response to RTS 3. CTS heard by all nodes a) Sender transmits data frame b) Other situations defer transmissions
RTS-CTS exchange
31
What part of the 802.11 frame is described below? MAC address of wireless host / AP to receive this frame
Address 1
32
What part of the 802.11 frame is described below? MAC address of wireless host / AP transmitting this frame
Address 2
33
What part of the 802.11 frame is described below? Duration of received transmission time
Duration
34
What part of the 802.11 frame is described below? Frame type
Type
35
What part of the 802.11 frame is described below? Frame sequence number - used for reliable data transfer
Sequence control
36
What part of the 802.11 frame is described below? MAC address of router interface to which AP is attached
Address 3
37
What part of the 802.11 frame is described below? Address used only in ad hoc mode
Address 4
38
What are the 2 advanced capabilities of 802.11?
Rate adaption & power management
39
What element of the 4G LTE architecture is described below? - 64 bit International Mobile Subscriber Identity IMSI) stored on Subscriber Identity Module (SIM) card - User Equipment (UE) in LTE jargon
Mobile device
40
What element of the 4G LTE architecture is described below? - Stores info about mobile devices for which the HSS's network is their "home network" - Works with MME in device authentication
Home Subscriber Service (HSS)
41
What element of the 4G LTE architecture is described below? - Device authentication coordinated with mobile home network HSS - Mobile device management - Tracking of device location - Path (tunneling) setup from mobile device to P-GW
Mobile Management Entity (MME)
42
What element of the 4G LTE architecture is described below? - At "edge" of carrier's network - Manages wireless radio resources & mobile devices in its coverage area / "cell" - Coordinates device authentication with other elements - Similar to WiFi AP - eNode-B in LTE jargon
Base station
43
What element of the 4G LTE architecture is described below? - Lies on data path to mobile / from Internet - One of them is a gateway to mobile cellular network, looks like internet gateway router and provides NAT services - Routers have an extensive use of tunneling
Serving Gateway (S-GW), PDN Gateway (P-GW)
44
Is the data plane or the control plane in LTE described below? New protocols for mobility management, security & authentication
Control plane
45
Is the data plane or the control plane in LTE described below? New protocols at link & physical layer. Extensive use of tunneling to facilitate mobility.
Data plane
46
Which channel in the LTE radio access network is described below? FDM, TDM within frequency channel
Downstream channel
47
Which channel in the LTE radio access network is described below? FDM, TDM similar to OFDM
Upstream channel
48
Which LTE link layer protocol is described below? Header compression & encryption
Packet Data Convergence
49
Which LTE link layer protocol is described below? Fragmentaton/reassembly & reliable data transfer
Radio Link Control (RLC) protocol
50
Which LTE link layer protocol is described below? Requesting & use of radio transmission slots
Medium Access Control (MAC)
51
What sleep mode in an LTE mobile is described below? After 100 ms of inactivity. Wake up periodically to check for downstream transmissions.
Light sleep
52
What sleep mode in an LTE mobile is described below? After 5 - 10 s of inactivity. Mobile may change cells while in this sleep - need to reestablish association
Deep sleep
53
Which part of the global cellular network is described below? Identifies and services info, while in home network & roaming
Home network HSS
54
Which part of the global cellular network is described below? Carriers interconnect with each other, and public internet at exchange points
All IP
55
What property of 5G is described below? - 2 frequency bands with mm wave frequencies. These frequencies enable much higher data rates over shorter distances. - Not backwards compatible with 4G - MIMO: multiple directional antenna
5G New Radio (NR)
56
In comparison to 4G, does 5G have an increased or decreased peak bitrate?
Increased
57
In comparison to 4G, does 5G have an increased or decreased latency?
Decreased
58
In comparison to 4G, does 5G have an increased or decreased traffic capacity?
Increased

Kommunikasjon - Tjenester og nett (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions