Effects of diversity combining, coding and equalization on digital microcellular mobile communications systems
[Thesis]
A. S. M. Al-Ahmari
King Fahd University of Petroleum and Minerals (Saudi Arabia)
1994
132
M.S.
King Fahd University of Petroleum and Minerals (Saudi Arabia)
1994
The effects of diversity combining, coding, and equalization on the performance of digital microcellular mobile communication systems, operating over frequency-selective fading channels, are studied using computer simulations. The presence of co-channel interference and additive white Gaussian noise is assumed. The multiple-access channel is statistically modeled by Rician distributed plus lognormally shadowed desired signal and several uncorrelated Rayleigh plus lognormally shadowed interfering signals, propagating according to dual path loss law with a turning point. The modulation schemes considered are BPSK, and DPSK. The channel is modeled by two beams with a relative delay between them. The performance is determined in terms of bit error rate (BER), and spectrum efficiency. It is shown from the computer simulations done on the system that with dual diversity combining and BPSK modulation the irreducible bit error rate (IBER), due to co-channel interference and intersymbol interference (ISI), is reduced from 3.0 usd\timesusd 10 to 1.35 usd\timesusd 10. Also, with linear adaptive equalization and BPSK modulation, the IBER is reduced to 8.0 usd\timesusd 10. The use of Golay (23, 12) code with BPSK modulation enhances the performance of the system by 23.8 dB coding gain at 3.0 usd\timesusd 10 BER.