Define the following terms regarding wireless communication: Half duplex channel, Base station, Mobile Switching Centre.
[3 marks]With figure explain Frequency Reuse concept in detail. Define cluster size and write the equation for system capacity.
[4 marks]Draw a neat sketch of GSM architecture and state the functions of the following: BSC, MSC, VLR, HLR, AUC.
[7 marks]Explain the concept of trunking and grade of service.
[3 marks]Why hexagonal cell shape is preferred in cellular architecture?
[4 marks]What is ZigBee? Explain in details ZigBee networks.
[7 marks]Calculate the worst-case carrier to interference ratio for a mobile receiver located at the boundary of its serving cell if it is under the influence of interfering signals from two nearest co-channels cells in a cellular system. Assume 3-sectors per cell and a reuse pattern of 4.
[7 marks]Explain the concept of umbrella cell and cell dragging in brief.
[3 marks]Explain the factors influencing small scale fading.
[4 marks]Explain :(1) Cell splitting (2) Microcell Zone concept. To improve coverage and capacity of a system.
[7 marks]Explain Time Division Multiple Access (TDMA) in wireless communication with figure.
[3 marks]Explain the Frequency diversity techniques briefly.
[4 marks]Derive an expression for a ground reflection model assuming distance between transmitter and receiver antenna is very large compare to heights of the antennas.
[7 marks]Explain paging system.
[3 marks]Compare FDMA with CDMA technique.
[4 marks]Briefly discuss security threats in wireless network and suggest possible ways of protection.
[7 marks]A Wi-Fi system operates at 1 Mbps. Calculate the data transfer time required for a 20 KB file.
[3 marks]Describe evolution of 2G and 3G mobile phone system in brief.
[4 marks]Assume a cellular system of 32 cells with a cell radius of 1.6km, a total spectrum allocation that supports 336 traffic channels, and a reuse pattern of 7. Calculate the total service area covered with this configuration and number of channels per cell.
[7 marks]Define mean excess delay, rms delay spread and excess delay spread.
[3 marks]Explain briefly how a RAKE receiver improves the received signal strength.
[4 marks]If a total of 33 MHz of band width is allocated to a particular FDD cellular telephone system which uses two 25 KHz simplex channels to provide full duplex voice and control channels, compute the number of channels available per cell if a system uses: (1) four cell reuse (2) seven cell reuse and (3) 12 cell reuse.
[7 marks]List types of diversity techniques and explain any one of them in 3-4 sentences.
[3 marks]Define following terms:
[4 marks]Dwell time (ii) Soft handoff (iii) mobile assisted handoff (iv) Transceiver
[ marks]In a cellular radio operating at 800 MHz, the transmitter and the receiver are separated by 500m from each other. The knife-edge diffraction object between them has a height of 30 m. The diffraction object is 100 m from transmitter. Find: (i) The excess path length (ii) The phase difference corresponding to the excess path length. (iii) The Fresnel-Kirchhoff diffraction parameter. (iv) The radius of the second Fresnel zone.
