Wireless Communication Questions

SET I

(3 Hours) [Total Marks:100]

NB:
1. Question No.1 is compulsory
2. Attempt any four out of the remaining six questions

Q1. a. Describe the two common modulations techniques – FDM and CDMA.
How interference is avoided using FDM? List benefits of using CDMA
in wireless data transmission.
(10)

b. What are the advantages and disadvantages of Wireless LAN over
wired LAN? Explain why CSMA/CD cannot be implemented in
Wireless LAN.
(10 )

Q2. a. What are the functions performed by an antenna? What is an isotropic
antenna? What factors determine antenna gain?
(10 )

b. Explain the term fading in the mobile environment.
Suppose that a transmitter produces 100 W of power
1. Express the transmit power in units of dBm and dBW
2. Write down the expression for free space power loss (by
attenuation) in terms of distance and wavelength.
(10 )

Q3. a. Why is Error Correction important in wireless data transmission?
Differentiate between error correcting codes and error detecting codes.
(10)

b. What are Block codes and Convolution codes?
In an(n,k) Block Error Correcting Code what do n and k represent?
(10)

Q4. a. How is Spread Spectrum technique useful in wireless communication?
What are FHSS and DSSS techniques?
(15)

b. State in brief the salient feature of Cellular Networks. ( 5 )

Q5. a. What issues have influenced design of IEEE 802.11 Wireless LAN
standard?
(5)

b. What is frequency band used for Wireless LAN under IEEE 802.11 a/b
standard? Describe the 802.11 architecture and services.
(15)

Q6. a. Describe Bluetooth applications, architecture.
What are Piconet and Scatternet? What is active state v/s parked state?
(10)

b. Describe the protocol stack in Bluetooth.
What are the error correction and security schemes used in Bluetooth?
(10)

Q7 Write short notes on TWO of the following: (20)
a. Mobile IP
b. WAE/WAP
c. GSM
d. IEEE 802.16