Answer the following problems.
problem 1) A vehicle receives a 900 MHz transmission while travelling at a constant velocity for 10s. The average fade duration for the signal level 10 dB below the rms level is 1 ms. How far does the vehicle travel during the 10s interval? How many fades does the signal undergoes at the rms threshold level during a 10s interval? Suppose that the mean remains constant during travel.
problem 2) Describe briefly with suitable block diagram ISDN networks.
problem 3) If probability of error P_{e}= 10^{–3}, find out the processing gain required for a CDMA system to have simultaneous 20 users.
problem 4) Describe the limitation of wireless networking.
problem 5) The IS-95 system uses a rate 1/2 convolution encoding in the forward channel and a 1/3 convolution coding in the reverse channel. What were the reasons for doing so?
problem 6) Describe GSM system architecture and its different channel types.
problem 7)(a) Describe briefly the different diversity techniques used to improve wireless links.
(b) Suppose four branch diversity is used, where each branch receives an independent Rayleigh fading signal. If average SNR is 20 dB, find out the probability that the SNR will drop below 10 dB. Compare this with the case of a single receiver without diversity.
problem 8) Describe in detail signalling system No. 7 (SS7) protocol, its NSP, user part and signalling traffic.