Question:

(a) Describe the term interference in the space, time, frequency, and code domain.

(b) Consider a 1 G - AMPS: 824-849 MHz (forward) ; 869-894 MHz (reverse). Bandwidth allocated to each user in each link is 30 kHz and a 2G GSM network: 935-960 MHz(forward) , 890-915 MHz(reverse), Frequency Carrier: 200 kHz with TDMA of 8 time slots per frequency carrier.

(i) Calculate the number of user channels in both cases.

(ii) Consider re-use factor is 7 for AMPS and 3 for GSM, calculate the number of users per cell in both cases?

(c) Each channel of the ISI of the CDMA system IS-95 occupies 1.25 MHz of the spectrum of each one way link. Bands of 25 MHz are available in each direction. The maximum user rate R = 9.6 kbps. If a minimum acceptable Eb/I0 is 6 dB, determine the capacity of a CDMA system using

(i) Omnidirectional base station antenna and no voice activity detection

(ii) 3-sectored antennas at the base station with γ_a = 2.4 and γ_v = 2.6.

(d) For the WCDMA there are available bands of 1920-1980 MHz in reverse direction and 2110-2170 MHz in forward direction, that is, 60 MHz in each direction. The speech codec in WCDMA employs the AMR technique standardized in 1999. It has 8 source rates from 4.75 kbps up to 12.2 kbps. Each channel of the WCDMA system occupies 5 MHz of the spectrum on each link. Consider the user rate is 12.2 kbps. The other parameters are the same as in (c). Find the capacity of the WCDMA under the given conditions.