Visvesvaraya Technological University (VTU) 2007 B.E Computer Science on mobile communications - Question Paper

7.4 Compare IEEE 802.11, HiperLAN2, and Bluetooth with regard to their ad-hoc
capabilities. Where is the focus of these technologies?
7.5 If Bluetooth is a commercial success, elaborate remaining reasons for the use of
infrared transmission for WLANs?
7.6 Why is the PHY layer in IEEE 802.11 subdivided? What about HiperLAN2 and
Bluetooth?
7.7 Compare the power saving mechanisms in all 3 LANs introduced in this chapter.
elaborate the negative effects of the power saving mechanisms, elaborate the tradeoffs
ranging from power consumption and transmission QoS?
7.8 Compare the offered QoS in all 3 LANs in ad hoc mode. What advantages does
an additional infrastructure offer? How is QoS given in Bluetooth? Can 1 of the
LAN technologies offer hard QoS (i.e., not only statistical guarantees regarding a
QoS parameter)?
7.9 How do IEEE 802.11, HiperLAN2 and Bluetooth, respectively, solve the hidden
terminal problem?
7.10 How are fairness issues regarding channel access solved in IEEE 802.11,
HiperLAN2, and Bluetooth respectively? How is the waiting time of a packet ready to
transmit reflected?
7.11 What various solutions do all 3 networks offer regarding an increased reliability
of data transfer?
7.12 In what situations can collisions occur in all 3 networks? Distinguish ranging from
collisions on PHY and MAC layer. How do the 3 wireless networks try to solve the
collisions or minimize the probability of collisions?
7.13 Compare the overhead introduced by the 3 medium access schemes and the
resulting performance at zero load, light load, high load of the medium. How does the
number of collisions increase with the number of stations trying to access the
medium, and how do the 3 networks try to solve the problems? What is the
overall scalability of the schemes in number of nodes?
7.14 How is roaming on layer two achieved, and how are modifications in topology reflected?
elaborate the differences ranging from infrastructure based and ad hoc networks
regarding roaming?
7.15 elaborate advantages and issues of forwarding mechanisms in Bluetooth networks
regarding security, power saving, and network stability?
7.16 Name reasons for the development of wireless ATM. What is 1 of the main
differences to Internet technologies from this point of view? Why did WATM not
succeed as stand-alone technology, what parts of WATM succeeded?
8. Mobile network layer
8.1 Recall routing in fixed IP networks (Kurose, 2003). Name the consequences and
issues of using IP together with the standard routing protocols for mobile

Earning:   Approval pending.