Chapter-1: Overview of Computer Networks
January-2004 [0]
July-2004 [10]
1.
e) Give an example protocol for each of the following layers in the OSI network stack: MAC, Network, Transport, Session. [4]
4.
a) What are the advantages of a layered protocol design and implementation? Suppose a new link layer technology is invented today, explain, how layering helps in integrating this technology into the current Internet? [4]
b) Can there be a network stack implementation, which does not include all the layers of the OSI reference model? Explain the significance of the word "reference". [2]
January-2005 [10]
1.
a) Explain the relationship between layers at an interface by defining PDU, SDU and IDU. [4]
7. Write short notes on
c) Traditional and mobile transport layer. [6]
July-2005 [18]
2.
a) Discuss the major advantages and disadvantages of layered model? How many layers are used in mobile communication systems? Name them. [9]
b) What do you understand by “broadcast network”? Discuss the need for a network layer (OSI layer 3) in a broadcast network. [9]
January-2006 [16]
1.
a) How do the layers of TCP/IP protocol suite correlate to the layers of the OSI? [4]
2.
a) What are connection oriented and connectionless services? What are service primitives? Explain with an example how these are used. [6]
b) Discuss the role of transport layer and data link layer in the OSI model. [6]
July-2006 [30]
1.
a) What is a bridge? Discuss the purpose and advantages of a bridge. [4]
c) Explain the terms Attenuation, Delay, distortion and noise. [4]
f) Explain the concept of interfaces and services. What is the relation between Layers at an interface? [4]
3.
a) Discuss the advantages and disadvantages of packet switching over circuit switching? [6]
7. Write short notes on the following:
b) Comparison between OSI reference model and TCP/IP suite [6]
c) Traditional and mobile transport layer [6]
January-2007 [9]
3.
a) Explain the data transfer services that OSI defines for the discrete data components passed across the interface and between peer entities. [9]
July-2007 [23]
1.
d) What are the types of care-of-address in mobile IP? [4]
f) What are the classes of IP addressing scheme and how many numbers of host-Ids and Network-Ids are there in each class? [4]
4.
a) Mobile IP provides the ability of a host to stay connected to the internet regardless of their location and without needing to change the mobile host’s long-term IP address. Explain Mobile IP operation with suitable diagrams. [9]
5.
a) Open System Interconnection is widely used for communication standard. What are Interface Data Unit, Service Data Unit and Protocol Data Unit with reference to OSI model? [6]
January-2008 [8]
1.
a) How does LLC sublayer ensure to transport efficiently multimedia traffic over the radio interface? [4]
4.
a) What are the advantages and disadvantages of layered model? [4]
Chapter-2: Multiple Access Technologies for Wireless Communication
January-2004 [8]
1.
e) Is it possible to transmit a digital signal e.g. coded as square wave as used inside a computer using radio transmission without any loss? If yes, how and why? [4]
f) What limits the number of simultaneous users In a TDM/FDM system compared to a CDMA system? What happens to the transmission quality of connections if the load gets higher in a cell? How does an additional user Influence the other users in the cell? [4]
July-2004 [0]
January-2005 [23]
1.
b) Give four reasons for the failure of many MAC layer (used in wired networks) protocols being applied to wireless networks. [4]
e) What is QPSK? How is it used in CDMA? [4]
2.
a) Explain, how does Slotted ALOHA work? Compare and contrast the basic MAC technologies used in FDMA, TDMA and CDMA. [9]
7. Write short notes on
a) Efficient frequency utilization techniques employed in mobile communications. [6]
July-2005 [22]
1.
a) For a cluster of size N, how many total channels are available if each cell is allocated a group of k channel in a Cellular System using FDMA? [4]
3.
a) Discuss the problems of hidden and exposed terminals. What happens in the case of such terminals if ALOHA, slotted ALOHA or MACA is used? [9]
4.
b) Briefly discuss the operation of a CDMA multiple-access system. In what ways is it superior to TDMA? Mention the potential applications of CDMA. [9]
January-2006 [28]
1.
b) Compare the performance of slotted aloha with that of pure aloha. What is the limitation of aloha protocol in general? [4]
2.
c) What is spread spectrum communication. Explain the terms processing gain, pseudo random code generator and Walsch code. [6]
3.
b) Draw the detailed block diagram of a cellular system and explain. Also explain the different strategies implemented to avoid interferences in TDMA, FDMA & CDMA systems. [9]
7.
b) What is frequency management? Discuss different fixed channel assignment strategies. What are its limitations are compared to non-fixed channel assignment methods. [9]
July-2006 [10]
1.
d) What are the various multiple access technologies for Cellular Systems? Explain any one of them. [4]
4.
b) i) What is the maximum throughput of a pure ALOHA network with large number of
users and transmission rate of 1 Mbps?
ii) What is the throughput of a TDMA network with transmission rate of 1 Mbps?
- What is the throughput of the ALOHA network if only one user was effective with
transmission rate of 1 Mbps? [6]
January-2007 [18]
1.
f) How does CDMA system use signals that arrive in the receivers with different time delays? [4]
2.
b) What are the various strategies implemented to avoid interferences in TDMA, FDMA & CDMA systems. [5]
4.
b) Discuss the problems of hidden and exposed terminals. What happens in the case of such terminals if ALOHA, slotted ALOHO or MACA is used? [9]
July-2007 [19]
1.
e) Time Division Multiple Access is a technique of transmitting / receiving data between two devices. How is data transferred in TDMA? [4]
4.
b) A pure ALOHA system used packets of size 1000 bits and channel transmission rate of 10 Mbps. The packet generation is a Poisson process with average rate of 103 packets/sec. Obtained the normalization throughput. [9]
5.
c) How is spread spectrum implemented by using frequency hopping? [6]
January-2008 [21]
2.
a) A pure ALOHA network transmits 200-bit frames on a shared channel of 200 kbps. What is the throughput if the system (all stations together) produces 1000 frames? [6]
4.
c) Briefly discuss the operation of a CDMA multiple access system. In what ways it is superior to TDMA? Mention the potential application of CDMA. [9]
5.
a) Differentiate between slotted ALOHA and Pure ALOHA? Discuss the limitation of pure ALOHA. [6]
Chapter-3: Mobile Data Communication
January-2004 [62]
1.
a) Why is frequency reuse necessary in cellular telephony? Find out the expression for frequency reuse. [4]
b) Sometimes when a cellular user crosses the boundary from one cell to another, the current call is abruptly terminated, even though all transmitters and receivers are functioning perfectly. Why? [4]
2.
a) What are the main problems of signal propagation? Why do radio waves not always follow a straight line? Why Is reflection both useful and harmful? [9]
b) Discuss the following techniques used to improve capacity in cellular system:
i) Cell Splitting
ii) Sectoring.
Which technique Is more efficient and why? [9]
3.
a) Explain various channel assignment strategies used in cellular communication. Describe how a mobile to wire line call is established in cellular radio system. [9]
b) Determine the number of full duplex channels available in a cluster and the total capacity for a cellular system where there are 10 clusters, each containing 20 cells with 18 channels in each cell. Also, determine the co-channel reuse ratio for each cluster. [9]
4.
a) Describe the handoff feature in a cellular radio system. Explain the difference between soft and hard handoff. [10]
b) What is co-channel interference? List various strategies to reduce co-channel interference. Explain any two in detail. [8]
July-2004 [52]
1.
c) What are the different ways in which radio waves can propagate? Mention the role of the radio wavelength where it is relevant. What causes multi-path interference? [4]
2.
a) Briefly mention as to why control channels are required between a BTS and a mobile. What is the control channel used by the BTS for passing information regarding the cell parameters? What is the control channel used to find out if a particular mobile is present in a cell? [3]
b) Which control channel is used for setting up a mobile originated call? Why is collision between multiple mobiles possible in this case? What is the multiple-access protocol used? How is the Access Grant Channel (AGCH) used to reduce the number of collisions? [5]
c) What is the need of a Fast Associated Dedicated Control Channel (FACCH)? How is FACCH implemented? When is it used? [3]
4.
c) Suppose that you have a simple packet switched network with three nodes A, Band C connected as A-B-C, with B acting as a router for packets between A and C. Suppose that both links A-B and B-C have a capacity of B bytes/sec. The packets from A to C have a payload size of P bytes and a header size of 40 bytes. What is the maximum throughput possible' between A and C in terms of P and B? [2]
d) What is the latency experienced by packets between A and C? Assume that the propagation delays are negligible. [1]
e) Suppose now that each payload is split into two fragments of (P/2) bytes each. Each fragment thus has a separate header. What is the maximum throughput possible in this scenario? [2]
f) In the same fragmentation scenario as above, what is the latency seen by packets between A and C (compute the latency of packets, not each of the fragments). [3]
g) By comparing your answers in parts (d) and (f) above, determine the value of payload size P for which the latency is the same even after fragmentation. How do the two latencies compare for lower values of P than what you determined for higher values of P? [4]
5.
a) While measuring the signal strength to decide whether or not to handoff to an adjacent cell, why is it important to average over time? Is soft-handoff possible in a GSM network? Why or why not? [2]
b) What is ping-ponging effect in hand off? Does it occur in soft-handoff or hard-handoff? How can it be prevented? [5]
c) Differentiate between terminal mobility, personal mobility and service portability with a brief explanation for each. [6]
7.
c) What is the difference between error-detection and error-correction? Which requires more overheads? [2]
d) What is Hamming distance? Suppose the Hamming distance between two codewords in an error-correcting scheme is 4, how many bit errors can this scheme correct? Why? [3]
e) What are the trade-offs in the use of error-correcting codes as opposed to using ARQ? For what kind of applications is an error correcting code more appropriate? [3]
f) What is an error burst? Explain, how this can be countered using block interleaving.
[4]
January-2005 [8]
1.
c) Give the relations to calculate transmitted power and co-channel reuse distance of wireless cellular systems. [4]
d) Explain the terms ‘Handoff mechanism’ and ‘Cell splitting’. [4]
July-2005 [38]
1.
c) Find the co-channel reuse ratio Q if the cluster size N is 9. [4]
d) What is the difference between inter-cell handoff and intra-cell handoff? [4]
f) Assume all stations can hear all other stations. One station wants to transmit and senses the carrier idle. Why can a collision still occur after the start of transmission? [4]
3.
b) Differentiate between Circuit Switched Data Services and Packet Switched Data Services on Cellular Networks. [9]
4.
a) Discuss the make-before-break and break-before-make handoff procedures. Propose methods that could be used by a base station to determine the vehicular speed of a mobile user. Are these methods useful for handoff algorithms? [9]
8.
a) What are the factions that influence small scale fading? What causes multipath fading? How can Multipath fading be reduced? [8]
January-2006 [17]
1.
c) Explain the concepts of handoff and dropped call rate. What are soft and hard handoffs. [4]
e) If 20 MHz of total spectrum is allocated for a duplex wireless cellular system, with Simplex channel has 25KHz RF bandwidth, find the number of duplex channels and number of channels per cell site, if N=12 cell reuse is used. [4]
3.
a) What are mobile data communication services and name them. Describe the architecture of HSCSD (High Speed Circuit Switched Data). [9]
July-2006 [10]
1.
g) Explain the Circuit-Switched Data Services on Analog Cellular Networks. [4]
2.
c) A network is to be planned using cellular topology. If total available bandwidth is 25MHz and each user requires 30KHz bandwidth for voice communication. 20 lower power antennas are used and the frequency band is divided in to four sets and one set is assigned to each cell. Find the number of simultaneous users. [6]
January-2007 [19]
1.
c) What are the different ways in which radio waves can propagate? Mention the role of the radio wavelength where it is relevant. What causes multi-path interference? [4]
5.
c) For a cluster of size N, how many total channels are available if each cell is allocated a group of k channel is a Cellular System using FDMA? [6]
6.
b) Differentiate between Circuit Switched Data Services and Packet Switched Data Services on Cellular Networks. [9]
July-2007 [9]
7.
a) Cellular Digital Packet Data (CDPD) was designed to maximize the use of existing functions and capabilities in Analog Mobile Phone System. Explain CDPD network architecture. [9]
January-2008 [31]
1.
e) List four significant factors which influence the choice of speech-coders in mobile communication. Which factor influences more as per your opinion? Give reasons. [4]
g) Explain the architecture and features of “Short Message Service”. [4]
3.
a) What is channelization? Explain at least two channelization protocols in detail? [9]
4.
b) Explain small scale multipath propagation. Discuss the factors that influence small scale fading. [5]
7.
b) Discuss the features of the following:
i) Circuit Switched Data Services
ii) Packet Switched Data Services. [9]
Chapter-4: Personal Wireless Communication Systems
January-2004 [4]
1.
g) What Is likely to happen to a DECT if it is deployed outdoors in an environment where significant multipath could occur? Explain your answer and provide qualitative analysis. [4]
July-2004 [3]
5.
e) What is the role of the unique personal number in Universal Personal Telecommunications (UPT)? [3]
January-2005 [0]
July-2005 [0]
January-2006 [18]
1.
d) Draw and discuss the conceptual model of DECT (Digital European Cordless Telephone). Give its application areas. [4]
4.
a) Give an account of radio specifications for cordless telecommunication systems such as CT2and DECT. [6]
c) Draw and explain the functional architecture for PACS (Personal Access Communication System). Discuss the frame structure and its radio aspects. [8]
July-2006 [0]
January-2007 [0]
July-2007 [8]
2.
c) Describe Digital Enhanced Cordless Telecommunication system and the protocol architecture. [8]
January-2008 [10]
1.
c) What are the data and messaging services supported by Personal Access Communication System (PACS)? Explain briefly. [4]
5.
b) What are the application areas of DECT? Discuss the conceptual model of DECT in brief. [6]
Chapter-5: Digital Cellular Systems and Standards (2G)
January-2004 [9]
7.
a) Describe the GPRS architecture and protocols. How many of them already exist In GSM? Compare the channel request procedure in GPRS with that in GSM. [9]
July-2004 [17]
1.
g) Both GSM and DECT are digital wireless communication standards for voice. What is the difference in terms of the intended coverage area and mobility supported by the two? Which one of them defines detailed network architecture for roaming across various providers' networks? [4]
2.
d) Draw the GPRS architecture showing the main components. Which is the component responsible for assignment of an IP address to the mobile? Why does there need to be a mapping between the mobile's IMSI and its IP address? [7]
5.
d) GSM uses the SIM card to identify a particular user. The user can use the same SIM card on any cellular phone. Is this an example of terminal mobility or personal mobility? Why? [2]
7.
b) Which is the 2G technology, which uses CDMA? How do the three CDMA variants 1XMC, 3XMC and HDR differ in terms of bandwidth usage? [4]
January-2005 [31]
1.
f) In each GSM multi frame, 24 frames are used for traffic and two for associated control signaling. Considering the detailed burst frame and multi frames infrastructures, explain, how the effective transmission rate for each GSM voice traffic is 22.8 kbps. [4]
2.
b) Draw the CDMA based mobile system architecture and explain how it provides reliable basic phone services. Write the benefits of CDMA to users. [9]
6.
a) Draw the basic reference architecture and signaling interfaces of GSM. Why SIM card needed in GSM, while it is not required in AMPS? [9]
b) How do you compare AMPS and GSM systems in terms of coverage area, transmitted power and error control system? Explain, what you can do to address adjacent channel and co-channel interference. [9]
July-2005 [24]
5.
a) If 8 speech channels are supported on a single radio channel and if no guard band is assumed, what is the number of simultaneous users that can be accommodated in GSM? [9]
7.
a) Discuss the GSM Reference Architecture in detail. What is the function of the following:
i) Mobile Station (MS)
ii) Base Station System (BSS)
iii) HLR
- VLR
v) Authentication Centre [10]
8.
b) Write short notes on any two topics
i) GPRS Architecture [5]
January-2006 [31]
1.
f) Compare and contrast the various 2.5G technology paths that each of the major 2G standards provide. Which path has the highest Internet access speed? [4]
5.
a) Draw CDMA based mobile system architecture and explain, how it provides reliable basic phone services. Write the benefits of CDMA to users. [9]
b) Draw the basic reference architecture and signaling interfaces for GSM. Why is Smart card needed in GSM, while it is not required in AMPS? [9]
6.
a) How do you compare D-AMPS and GSM systems in terms of coverage area, transmitted power and error control system, explain what you can do to address adjacent channel and co-channel interference. [9]
July-2006 [24]
2.
b) What are the main elements of GSM System architecture? Discuss the reasons of separate MS and SIM in GSM. [6]
4.
a) Using QPSK modulation and convolutional coding, the IS-95 digital cellular systems require 3dB < Sr < 9 dB. The bandwidth of the channel is 1.25 MHz., and the transmission rate is R = 9600 bps. Find the capacity of a single cell IS-95 cell. [6]
6.
a) What is GPRS? Describe the GPRS architecture and protocols. [12]
January-2007 [23]
1.
e) In each GSM multi frame, 24 frames are used for traffic and two for associated control signaling. Considering the detailed burst frame and multi frames infrastructures, explain, how the effective transmission rate for each GSM voice traffic is 22.8 kbps. [4]
2.
a) How is signaling protocol in GSM structured into layers? What are the specific functions performed by Layer 3 of the GSM signaling protocol? [9]
c) If a normal GSM time slot consists of six trailing bits, 8.25 guard bits, 26 trailing bits and two traffic bursts of 58 bits of data, find the frame efficiency. [4]
5.
b) Using QPSK modulation and convolutional coding, the IS-95 digital cellular systems require 3dB < Sr < 9 dB. The bandwidth of the channel is 1.25 MHz., and the transmission rate is R = 9600 bps. Find the capacity of a single cell IS-95 cell. [6]
July-2007 [10]
2.
a) General Packet Radio System is radio access technology and provides packet data service. Explain the protocol architecture. [5]
b) Explain GSM architecture and frequency planning. [5]
January-2008 [15]
2.
c) If GSM uses a frame structure where each frame consists of eight time frame slots, and each time slot contains 156.25 bits, and data is transmitted at 270.833 kbps in the channel. Find
i) The time duration of a bit
ii) The time duration of a slot
iii) The time duration of frame. [6]
3.
b) Explain the typical call flow sequences in GSM. [9]
Chapter-6: Third Generation Mobile Services (3G)
January-2004 [0]
July-2004 [6]
1.
d) Give an application as an example, which will find use for the "streaming" class of QoS offered by UMTS. Also give an example application for the "interactive" class. Which 2.5G architecture is the UMTS core network based on? [4]
7.
a) What is W-CDMA? What are its advantages over TDMA? [2]
January-2005 [18]
5.
a) Summarize the main features of 3rd generation mobile phone system. How do they achieve higher capacities? How does UMTS implement asymmetrical communication and different data rates? [9]
b) What are the bandwidths and chip rates used in CDMA? Why does WCDMA use walsh codes in forward and reverse channels for separating users while in CDMA, one uses them only in forward channel. Assume we want to support a 19.2 kbps data service with ber (bit error rate) of 10-3 over WCDMA system. What is the minimum chip rate and bandwidth needed to support 100 simultaneous users with one carrier? Assume a performance improvement factor of K = 4(6dB). [9]
July-2005 [17]
6.
b) Explain various key characteristics that distinguish third generation cellular systems from second-generation cellular systems. [9]
7.
b) Differentiate between W-CDMA and CDMA-2000 mobile services and standards. [8]
January-2006 [9]
6.
b) With the help of a neat diagram explain the UMTS (Universal Mobile Telecommunication System) network architecture. Discuss in detail the logical parts: I) user equipment and ii) core network. How is the number of handoffs reduced of r the fast moving traffic? [9]
July-2006 [6]
2.
a) What are the key features of IMT-2000? What are the general requirements for Radio Access to IMT-2000? [6]
January-2007 [13]
1.
g) Compare and contrast the various 2.5G technology paths that each of the major 2G standards provide. Which path has the highest Internet access speed? [4]
4.
a) Summarize the main features of 3rd generation mobile phone system. How do they achieve higher capacities? How does UMTS implement asymmetrical communication and different data rates? [9]
July-2007 [18]
3.
a) Describe Functional Network Architecture for IMT-2000. What are the general requirements for IMT 2000? [9]
b) What are the key features of IS-95 CDMA System? Comment on the capability of CDMA systems. [9]
January-2008 [0]
Chapter-7: Wireless Local Area Networks (WLAN) : IEEE 802.11
January-2004 [22]
1.
c) How does IEEE 802.11 solve the hidden terminal problem? [4]
6.
b) What are the basic differences between wireless WANs and WLANs and what are the common features? Consider mode of operation, administration, frequencies, capabilities of nodes, services and national /internatlonal regulations for comparison. [9]
7.
b) What are advantages and problem of forwarding mechanisms in ad hoc networks regarding security, power saving and network stability? [9]
July-2004 [18]
3.
a) What is the difference between a LAN and a PAN? Why is 802.11 inappropriate for a PAN? [3]
b) The hidden-node problem is specific to wireless networks and no such problem exists in wired LANs. Why? [2]
c) What is narrow-band interference? Why is this to be avoided? What are the two spreading techniques in 802.11 to avoid this? Briefly explain how each of them work. Mention the modulation scheme used by each. Draw the transmit spectrum before and after spreading for each of the two techniques. [10]
d) In an 802.11 system implementing CSMA/CA, suppose the physical layer header size is H and the MAC/Link layer header size is M. Further, a stop-and-wait protocol is used at the link layer, with the acknowledgement packet size being A (including all headers). The size of RTS and CTS packets (including all headers) are Rand C respectively. For a MAC-level payload size of P, what is the throughput achieved as a fraction of the raw physical layer throughput? (Assume that all portions of the packet and the headers are all transmitted at the same speed). [3]
January-2005 [13]
1.
g) Name four major transmission techniques considered for WLAN standards and give the standard activity associated with each of them. [4]
3.
b) What are the advantages and problems of forwarding mechanisms in adhoc networks regarding security, power saving and network stability? Describe briefly infrastructure requirements of adhoc networks. [9]
July-2005 [14]
6.
a) Discuss the working of adhoc WLANs. Under what circumstances ad-hoc networks are preferred over Infrastructure WLAN? [9]
8.
b) Write short notes on any two topics
ii) FHSS vs. DSSS. [5]
January-2006 [4]
1.
g) Draw and explain the wireless LAN architecture and also explain the terms infrastructure mode and Adhoc mode. [4]
July-2006 [8]
1.
b) What are the benefits of spread spectrum? What is frequency-hopping spread spectrum? [4]
e) If a computer is connected to a wireless LAN then it can communicate with the Computers in wired LAN. Is the statement true? Justify by giving reasons. [4]
January-2007 [10]
1.
d) What is the difference between a LAN and a PAN? Why is 802.11 inappropriate for a PAN? [4]
5.
a) Why do we need different MAC schemes for wireless LANS? Explain briefly the hidden and exposed terminal problem associated with CSMA/CD. [6]
July-2007 [13]
1.
a) In context of Wireless Local Area Network give difference between ad-hoc Wireless LAN and Infrastructure Wireless LAN. [4]
6.
a) Explain the operation of MACAW protocol in WLANS. [9]
January-2008 [29]
1.
b) Differentiate between Direct Sequence and Frequency Hopping spread spectrum techniques. [4]
f) Discuss the advantages and disadvantages of Ad-Hoc Networks. [4]
2.
b) Discuss the advantages of WLAN. What are its disadvantages? What are design goals for WLANS? [6]
5.
c) What are the limitations in wireless networking? Discuss the security issues in wireless networks. [6]
7.
a) Explain, how MACAW protocol is operated in WLANS? [9]
Chapter-8: Wireless Application Protocol (WAP)
January-2004 [18]
5.
a) What Is the fundamental difference between WML and HTML? Why is this difference important with respect to hand held devices? [10]
b) What are the primary goals of the WAP Forum efforts and how are they reflected In the WAP protocol architecture? In which situation is WTP not used? What are the disadvantages of implementing TCP/IP directly over the mobile network? [8]
July-2004 [8]
1.
a) How can a Bluetooth network have more than 8 nodes? Draw such a network with 10 nodes and clearly mark the different nodes and parts of the network. [4]
b) What is the functionality of the WAP gateway? Why is this functionality required? Draw a simple diagram showing how the WAP gateway interfaces with wireless devices. [4]
January-2005 [24]
3.
a) Explain WAP stack. Prove that WAP session protocol and WAP transaction protocol over UDP conserves bandwidth as compared to TCP over IP. [9]
4.
b) How Internet may be supported on mobile links. Draw the architecture and functional components of mobile IP. Describe data transfer from a mobile node to a fixed node and vice-versa. [9]
7. Write short notes on
d) Wireless markup language. [6]
July-2005 [22]
1.
b) What is the fundamental difference between WML and HTML? [4]
g) What are the important functions of a WAP Gateway? [4]
5.
b) Why does WAP define its own security layers and does not rely on the security provided by the mobile phone network? Discuss the important functions WSP and WAE. [9]
8.
b) Write short notes on any two topics
iii) Blue-tooth Protocol stock [5]
January-2006 [9]
7.
a) Draw and explain the WAP network configuration. Also discuss the WAP protocol stack. [9]
July-2006 [24]
5.
a) What is mobile IP? Draw & describe the mobile IP architecture and its functional components. [12]
6.
b) Explain each of the following in detail with reference to WAP:
i) Wireless Datagram Protocol
ii) Wireless Transaction Protocol
- Wireless Session Protocol [6]
7. Write short notes on the following:
a) Blue tooth Protocol stack [6]
January-2007 [21]
1.
a) Why do not other RF (Radio Frequency) devices interfere with Bluetooth Devices? [4]
b) How does a WAP Gateways act as a bridge between the mobile world and the Internet? [4]
3.
b) What is mobile IP? Explain with the help of a neat diagram how a mobile user remains on line irrespective of his current position. [9]
7.
a) Explain briefly the types of links available with Bluetooth network. [4]
July-2007 [19]
1.
c) What are Wireless Application Protocol (WAP) gateway and its main functions? [4]
5.
b) Wireless Markup Language (WML) is optimized for limited capability devices and networks. Describe WML constrains, features and document model? [6]
6.
b) Bluetooth is aimed for ad-hoc network with a very limited coverage and without need for an infrastructure. Explain its Physical and Medium Access Control Layers. [9]
January-2008 [12]
1.
d) What is a Bluetooth technology? Discuss the different layers that Bluetooth uses. [4]
6.
b) Differentiate between:
i) Wireless Datagram Protocol and Wireless Transaction Protocol
ii) Wireless Session Protocol and Wireless Application Environment [8]
Chapter-9: Wireless in Local Loop (WLL)
January-2004 [9]
6.
a) Describe four major technologies for WLL system. What are the advantages and disadvantages of these approaches? What are the benefits of using 15-95 CDMA technology for WLL? [9]
July-2004 [0]
January-2005 [6]
7. Write short notes on
b) Wireless in Local Loop. [6]
July-2005 [5]
8.
b) Write short notes on any two topics
iv) WLL Architecture [5]
January-2006 [0]
July-2006 [12]
3.
b) Discuss the deployment issues with Wireless Local Loop (WLL). Explain Satellite based technology for WLL Systems. [12]
January-2007 [7]
7.
c) What are the factors that govern use and reuse of spectrum for WiLL? How does modulation efficiency influence use and reuse of spectrum? [7]
July-2007 [4]
1.
b) What are the benefits of using Wireless Local Loop (WLL) Technologies in broadband wireless access radio in loop? [4]
January-2008 [0]
Chapter-10: VSAT systems and Networks Security
January-2004 [4]
1.
d) Why does VSAT operate at slow data rates? [4]
July-2004 [22]
1.
f) Why is security in a wireless network a greater concern than in wired networks? Describe what is meant by authentication and point out how is it different from data protection through encryption? [4]
6.
a) What is a VSAT? What are its two main modules in installation and their functionalities? What are some advantages of using a VSAT? [6]
b) Depict the star topology of VSAT architecture in a simple diagram. Explain, how the latency of communication between two VSAT nodes could be high in this configuration. For what kinds of applications is this inappropriate? [4]
c) How does a mesh topology differ from a star topology? What is its advantage over a star topology? [2]
d) What is the main difference between TDMA and DAMA access methods for VSATs? Which is better in terms of cost and why? [3]
e) Explain, how VSATs can be used for one-way data systems (only the downlink). For what application is this useful and why? [3]
January-2005 [15]
4.
a) What are four aspects of Network security? Explain why public key encryption requires fewer keys than secret key encryption. Given two prime numbers p= 37 and q=23, define the private and public key by soliciting appropriate value of the number e. [9]
7. Write short notes on
e) VSAT Access Schemes. [6]
July-2005 [4]
1.
e) Which topology is generally deployed by VSATs and why? [4]
January-2006 [4]
4.
b) What is VSAT? Give the components of VSAT systems. [4]
July-2006 [12]
4.
c) What are the security requirements of wireless networks? [6]
5.
b) What is VSAT? What are the services supported by VSAT networks? [6]
January-2007 [16]
6.
a) Why is TDM/TDMA technology widely used in most of the VSATs installed globally? How can the frequency carrier be assigned between any two VSATs on a demand basis? [6]
c) Explain how VSATs can be used for one-way data systems (only the downlink). For what application is this useful and why? [3]
7.
b) Explain why public key encryption requires fewer keys than secret key encryption. Given two prime numbers p= 37 and q=23, define the private and public key by soliciting appropriate value of the number e. [7]
July-2007 [13]
1.
g) What are the basic problems which need to be addressed in VSAT networks? [4]
7.
b) Very Small Aperture Terminal (VSAT) in a satellite communication functions is an overhead wireless repeater station that provides a microwave communication link between two geographically remote sites. Specify the operation of VAST networks. Give suitable examples. [9]
January-2008 [10]
6.
a) Discuss the advantages and disadvantages of VSAT networks. Explain the operation of VSAT. [10]
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