Questions and Answers of Introduction Wireless Mobile Systems

The beam footprint depends on the inclination angle. What will be the impact on the coverage if the angle is changed from 35 to 30? Explain clearly.
Can you define 10 different bivariate polynomials?
Answer the following:(a) Do you recall any recent event that is an example of denial of service?(b) Can denial of service (DoS) be more effective if you have information about the traffic? Explain
Using your favorite MANET simulator, create a sensor network. Assuming appropriate parameters simulate a sensor network with 100 nodes. Find the query propagation time from one end of the network to
Using your favorite MANET simulator, create an arbitrary MANET and find disjoint paths between an arbitrary source-destination pair. Assume all needed parameters.
Who provides wireless services for an AP?
What type of 4-G coverage do you have in your area and how do you compare its performance with pre-exisiting 3-G services?
Find out the SMS service providers in your area? How can you compare their performance parameters?
Can you compare operating characteristics of Femto cells offered by different service providers?
Can you obtain information about different service providers supporting Femto cells?
From your favorite Web site, find out the acceptable bit error rate for the following applications:(a) Voice communication(b) Video communication(c) Defense applications(d) Sensor data communication
Many types of sensors are comercially available. Looking at different web sites, can you prepare their cost-size-performance tradeoff?
What phenomenon do you observe when a cell phone is used while traveling a long metallic bridge?
Look at your favorite web site and find what is meant by “web-in-the-sky”?
A snapshot of an ad hoc network is shown in Figure 13.19.Describe briefly the process taken to do the following:(a) You need to create a route from the source node 6 to the destination node 23 using
In a given large institution, there are two types of APs, pre-installed 802.11g APs and newer 802.11n APs. What are the advantages and limitations of such a deployment? Explain clearly.
A cellular system employs the CDMA scheme. Is it possible to use a composite TDMA/CDMA scheme? If not, why not; and if yes, what may be the potential advantages? Explain clearly.
What are the similarities and the differences between AMPS and GSM? Explain clearly.
What are the particular advantages and disadvantages of using a split TCP approach for wireless networks?
How can you provide security in IoT? Explain.
What the social implications of IoT? Explain clearly.
Can you use some devices to transmit data directly to BS while others using relay stations in LTE-A?
What kind of cognitive radio concept can be used to avoid interference between wireless nodes?
From your favorite Web site, find the differences between MIMO and smart antennas? What are their relative advantages? Explain clearly.
For Problem P18.4, can you use a normal voltage level for VLSI devices in handling high-priority traffic and a lower voltage level for low-priority traffic? Explain clearly.
Is it desirable to assign priority to traffic in a MANET? Explain.
In Problem P18.10, what are the security concerns you would have and how can you address them? Explain with suitable examples.In Problem P18.10, What kind of personal information would you like
In Problem P18.9, what kind of personal information would you like to maintain in the database and why is it important? Explain clearly.
In a center for mentally challenged people, a decision was made to monitor each individual person using wireless devices. Can you comment on the relative advantages and disadvantages of such an
You can envision a potential use of wireless technology in having robots with decentralized decision-making capability. Can you think of at least five applications? What are the limitations and how
Why is it important to use services of heterogeneous networks? Explain.
If preemption is allowed in Problem P18.4, how would you do the scheduling and what are the relative advantages and disadvantages?
What are the pros and cons of employing satellite communication for multicasting? Explain.
Assume that traffic is assigned four different priority levels taking into account real-time and handoff traffic. How can you handle such traffic while supporting mobility?
Can you use PTT technology to process multimedia traffic? Explain clearly.
Multimedia services have two components of video and voice data. Can you characterize them as non-real-time and real-time traffic? Explain clearly.
How is UWB different from the frequency hopping used in Bluetooth? Explain.
How do you compare the functionality of an earth station with the corresponding unit in the cellular system?
What are some unconventional uses of GPS?
How is the location of packets and parcels updated by United Parcel Service (UPS) or Federal Express (Fedex)? Explain clearly.
What are the different alternative techniques for determining location using cell phones? Explain the role of beacon signals.
From your local wireless service provider, find out if emergency 911 service is provided in your area and what kind of technique is used in location determination.
Is it possible to find a precise location inside a building or a room where GPS will not work? Explain.
How do you determine directions to an unknown destination using GPS technology?
Why are errors inherent in the triangulation technique? Explain clearly.
Why can there be more than one satellite orbiting in a single orbiting path of GPS?
In the satellite system, there is some degree of free space loss. Besides this loss, does it have any other source of loss? Explain.
How is the call setup in a satellite system different from a cellular system?
How do you compare delays in a satellite system versus a cellular system, versus an inter-terrestrial satellite system? How about the power level, coverage area, and transmission rates?
What are the advantages and disadvantages of LEO and GEO?
What are the differences between orbital and elevation angles of a satellite?
A code (n, k, t) is defined by k information bits and (n - k) redundant bits so as to correct t errors in the resulting word of n bits. Given a channel bit error rate of p, what is the word error
In Problem P17.7, if (128, 32) code is used for error correction, what is the fraction of information contents?
What is the information content if two-way diversity is used in a satellite system 10% of time by 50% of the traffic and the rest of the 50% traffic only 5% of time?
Setting up a path for a satellite phone subscriber requires a comprehensive hand-shaking mechanism between the MS, the satellite, and the BS. Prepare the steps that are desirable in setting up such a
If the isoflux area boundary is fuzzy, what should you do and what will be the overall impact on system performance? Explain clearly.
What should be the velocity of the satellite if it orbits around earth at a distance of 1000 km and weighs 2000 kg?
What will be the propagation delay between a satellite and an earth-based mobile station if the satellite is located at a distance of 850 km and if its inclination angle is 35?
What is the rationale behind using highly elliptical orbits? Explain.
How do the security issues vary from MANETs versus sensor networks versus WiMax versus WMNs? Explain clearly.
For Problem 16.25, you do need some forms of authentication and encryption. What are the most important parameters you would be concerned with? Explain clearly.
For Problem 16.25, you do need some software support. Can you think and outline how you would go about acquiring this? Explain.
In an amusement park, wireless devices are used to post the queue length and wait time for each of the rides. Can you think of an infrastructure that could enable patrons to do online interaction?
What type of security system would you suggest for a large WSN deployed in the form of a 2-D rectangular topology from the performance point of view? Explain clearly.
In a large sensor network of 1024 nodes, 32 clusters are formed, with each cluster consisting of 32 nodes. Each CH employees 32x32 2-D matrix based secured symmetric keys to communicate with each
How do the security issues vary from MANETs versus sensor networks versus WiMax versus WMNs? Explain clearly.
What can be the role of relay stations in providing secured communication in the 806.16j protocol?
In a sensor network, energy consumption is one of the major constraints. Keeping this in mind, what factors would one consider when designing a security scheme for such networks? Explain.
In organizing a conference, a single key has to be used by all program committee members to encrypt and decrypt the message. Assuming this key has to be changed every year, how can you set up such a
Can you define a trivariate polynomial f(x, y, z)?
How do you compare complexity of Bivariate polynomial with Ex-OR with a key for symmetric shared key? Explain clearly.
Given a bivariate polynomial function f(x, y) = x2 + y2 + x3 + y3 + 12x + 12y + 5, what will the shared key if x = 3 and y = 7?
How can you provide security in an ad hoc network? What are some possible schemes and their relative advantages?
A linear permutation i†’ (i + m) modn is used as shown in Figure 16.13. Does the encryption depend on the value of m ? What is the impact of increasing the value of m? Explain clearly.
The function of an 8x8 permutator is given by the following table:The following message is to be sent through the air:I AM DONE WITH MY FINALS AND NOW CAN TAKE A BREAK OR A VACATION.Find the message
Consider the word €œwireless,€ composed of eight symbols, each symbol being a letter of the English alphabet. This word is encrypted by first applying a permutation function and
(a) Using the public key of Problem P16.9, find the sequence of values transmitted through the air if the ASCII values corresponding to the following message are sent by the BS:I LIKE THIS CLASS.(b)
The function of a 10 x 10 permutator is given by the following table:(a) Find out the output message going through the air if the input message sequence is given by:I WANT TO LEARN ABOUT PERMUTATION
Why do you need to send a random number to test a MS? Explain clearly.
Answer the following:(a) How do you differentiate between privacy and security?(b) What are the differences between authentication and encryption?
In organizing a conference, a single key has to be used by all program committee members to encrypt and decrypt the message. Assuming this key has to be changed every year, how can you set up such a
How do you compare complexity of Diffie-Hellman algorithm with respect to RSA algorithm? Explain clearly.
Given a function KAB 2x 2y | mod 23 to be used between two wireless devices A and B, what will be the shared key if A sends a value 5 to B and B transmits 7 to A?
Given two prime numbers, p = 37 and q = 23, define the private and public keys by selecting appropriate values of the number “ e .”
In the RSA algorithm, the public key is transmitted to all MSs through the air by the BS. How is its security ascertained?
Can you envision LTE devices to be a router for a WMN? Explain clearly.
Describe the wireless solutions that you would recommend for the following situations. Some situations may need multiple standards. Explain clearly.(a) A person carries a PDA, laptop, bio-sensors,
What is the fundamental difference between the Ricochet solution and IEEE 802.16?
Compare the usefulness and limitations of WMANs, WLANs, and WPANs.
Compare HyperLAN 2 and Bluetooth.
Can you possibly use “orthogonal latic squares” to avoid the problem indicated in Problem P15.19. Find out details on “orthogonal latic squares” from a Web search. Explain clearly.
How do you ensure that two adjacent piconets do not use the same frequency-hopping sequence? Explain.
What is the rationale behind using different slot sizes in Bluetooth? Explain clearly.
Can you apply different ad hoc network routing protocols to a scatternet? Explain clearly with suitable examples.
A bridge node provides access between two adjacent piconets. How can you schedule from one piconet to bridge to the second piconet so that information can be transferred? Explain.
Forming a cluster of Bluetooth devices into a piconet is important. Can you think of any strategy to define members of a piconet? Justify your answer.
What are the advantages and disadvantages of using Bluetooth-based devices as a sensor network? Explain your answer from a possible feasibility point of view.
The group of reviewers is to be redistributed in the afternoon as follows: Group (A, B, E, F) and Group (C, D, G, H). Repeat Problem P15.11 for this new distribution.
In Problem P15.11(a), Group A may need to communicate with Group B about a submission, overlapping between the two subject areas. How is it possible to establish such an interaction? Consider all
Assuming that channel fi ≠ fj for i ≠ j , determine whether there can be a collision and an interference in Problem P15.10 if (a) Group (A, B, C, and D) or Group (E, F, G, and H) are

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