RGPV (IT-702) – Wireless and Mobile Computing – Solved Question Paper – To Score Better –

by

IT-702 (GS)

B.E. VII Semester  Examination, June 2020

Wireless and Mobile Computing

Q1. Explain the architecture of GSM in detail. Also discuss various services provided by GSM system?

  • Refer the following link for detailed answer and explanation on GSM networks, it’s main functional units like
    • Base station subsystem
    • Network switching subsystem
    • Operator support subsystem etc.

2. Write and explain the four major challenges for implementing Wireless LAN.

Source: Link 1 | Link 2

Refer the above links for major challenges related to wireless LAN.

OR

Draw and explain the architecture of 802.11a, 802.11b and 802.11c.

Source: Click me

Refer the following link for 802.11a architecture.

For 802.11b architecture refer this link.

Refer this Link 1 for wireless network architecture, go to page-4 of the slide.

Another good link source for ‘IEEE 802.11’ architecture, refer page-8 of the following link:

  • https://www.cse.wustl.edu/~jain/cse574-06/ftp/j_5lan.pdf

For components of 802.11 architecture refer this second link, which will describe about stations, basic service set, extended service set and distribution system.

To find which one of the three is best follow this third link.

3. What is handoff? Explain different handoff initialization techniques with suitable diagram.

Source: Click me

Define handoff in wireless communication.

When a mobile phone communicates with another base station while on an ongoing call with the help of mobile switching centre, it is called handoff.

And in standard language, handoff is called as the process in which the ongoing call or data connectivity is transferred from one base station to another base station.

What are different types of handoffs and difference between them?

There are two types of handoff soft handoff and hard handoff.

What happens in Soft Handoff?

In soft handoff at least one signal is kept active while making contact with another base station, is costly than hard handoff process and works on ‘make before break’ policy.

What happens in Hard Handoff?

In hard handoff connection actually breaks for some time while connecting to another base station, as a result if which there is no separate burden on the base station and the mobile switching centre. It works on ‘break before make’ policy

4. Draw and explain architecture of Ad hoc network. Write its characteristics and challenges.

Source: Link 1 | Link 2

Refer second paragraph in the above mentioned Link 1 for ad hoc network explanation or Link 2 for more detailed explanation.

5.

a)  Draw and explain the architecture of wireless sensor network. Write its applications.

Source: Click me

Refer the link mentioned above for in-depth explanation of wireless sensor networks and their detailed applications.

b)  Write explanatory note on Mobile IP and DHCP.

Source: DHCP | How mobile IP works?

6. Explain the following.

(i) Hidden and exposed terminals problems.

Source: Click me

What is exposed terminal problem?

A wireless local area network (LAN) faces exposed terminal problem, when one transmitting station is unable to send a signal because of interference from another transmitting station. This happens when there is no centralised facility to monitor these transmitting stations.

What is hidden terminal problem?

Hidden terminal problems happens when two or more stations that are not in each others range and they try to communicate with each other through a single recipient.

And this problem also arises due to the absence of any centralised monitoring or transmission system.

This hidden terminal problem happens when one access point is in range of one station and out of range of another station, and as a result of which it is not possible to make connection between the two.

(ii) Near and far terminals problems.

Source: Click me

What are near and far terminal problems?

Near and far problems or near-distance problems is a problem in which the nearby strong signal makes it very difficult for the receiver to capture the weak signal coming from a distance and it is a very common problem in wireless telecommunication systems.

It is also commonly used to jam nearby signals deliberately.

OR

Discuss the requirements and architecture of HIPERLAN-1.

Source: Click me

What is HYPERLAN ?

HyperLAN or High Performance Radio LAN is a European standard for effectively working wireless local area networks, also known as the European Alternative to IEEE 802.11, where IEEE is an international body.

HyperLAN is designed according to European telecommunications standards.

Because of IEEE, which is much faster and faster, HyperLAN was not so commercially successful.

For HYPERLAN requirements and architecture please refer this link.

7. Define the three classes of intruders and mention the intrusion techniques to protect from the intruders.

Source: Link 1 | Link 2

What are the three classes of intruders?

The three classes of intruders which are masquerader, misfeasor and clandestine user.

Masquerader: In this, a user who does not have authorisation to access the system enters the system by exploiting the account of a real or legitimate user.

Misfeasor: A user who is legitimate or authorised to access certain systems, accesses an unauthorised system or file, or misuse his authority.

Clandestine user: To suppress system audits when a user accesses their supervisory control, we call such user as clandestine user.

What are different ways to protect oneself from intruders?

Different ways to protect system from intruders are:

  • Create secure passwords
  • Do regular audit
  • Use authentic anti-virus and update it regularly
  • Update systems regularly
  • Activate firewall
  • Be aware of phishing emails etc.

8. Write short notes on any two.

a) Fire wall

Source: Click me | Link 2

  • What is firewall?

A firewall is a security layer that monitors incoming and outgoing traffic and allows only good users to access a website or other machine.

  • What is meant by good users in firewall?

In firewall good users are those users, who do not want to harm or damage your website or machine.

  • What is the main function of firewall?

Another function of firewalls is to help keep other harmful users and bots out of the website or bad users.

  • What are different types of firewalls?

There are 4 main types of firewalls viz. packet filtering, proxy service, stateful inspection and next generation firewall.

For description of the above 4 types of firewall please refer the links mentioned in source above.

b) CDMA

Source: Click me

What is CDMA?

Code-division multiple access (CDMA) main function is to send different or more signals through the same transfer channel. And in doing so using all the bandwidth it gets in the process.

Frequency for which CDMA is actually used?

It is used in mainly in ultra high frequency telephone communication systems, whose frequency is between 800 MHz to 1.9 GHz. And in doing so the entire bandwidth can be used by a single user for the entire time.

What are the main factors that decides CDMA capacity?

The main factors that decides CDMA capacity are processing gain, signal to noise ratio, voice activity factor and frequency reuse efficiency.

For advantages and disadvantages of CDMA refer the link mentioned above.

c) World Wide Web

Source: Click me

What is world wide web?

World Wide Web (WWW), Which is also commonly called as normally web actually helps in finding various types of information which is stored on different machines or servers of the world.

The stored material is available on a website in the form of text, image or as a service, which is then accessed or used by different users who have access to internet.

Every archived document has an address, which we also call as URL or Uniform Resource Locator. With its help, any data in the world can be accessed by anyone and everyone in seconds.

Who invented world wide web and when?

World wide web was invented by Sir Timothy Berners-Lee in 1989.

d) Trojan Horse Defence

Source: Click me

What is Trojan Horse?

A Trojan horse is a dangerous piece of software or code designed to harm your machine, which once enters your system can cause you a lot of damage.

It seems like a genuine action on websites or on emails on which once you click, download and install, can cause huge damage to your data, network etc..

  • Is Trojan Horse a Virus?

The virus grows very rapidly on its own, which the Trojan horse does not do and so we cannot call it a virus.

  • Whats are some common types of trojan viruses?

Different types of trojan viruses are backdoor trojan, downloader trojan, game-thief trojan, info stealer, mail finder, random, remote access, SMS etc. trojans.

Refer the link above for description of these different types of trojans.

Questions source: https://www.rgpvonline.com

Other relevant articles: