Effect of Coding in Digital Microcellular Personal Communication Systems with Co-Channel Interference, Fading, Shadowing, and Noise

An analytical model is developed for the performance of a microcellular radio network in the presence of co-channel interference and additive white Gaussian noise. The modulation schemes considered are BPSK, BFSK, and QPSK. The multiple-access channel is statistically modeled by one Rician-distributed desired signal and several uncorrelated Rayleigh plus log-normally shadowed interfering signals, propagating according to dual path loss law with a turning point. The performance is determined in terms of bit error rate (BER), outage probability , block error probability, crosstalk probability, and spectrum efficiency, considering both fast and slow multipath fading. The effect of error correction codes, consisting of blocks with equal number of bits, on the performance parameters is also studied. The computational results show that the propagation loss exponents, Rician factor, turning point, and cell size all play a major role in the design of an efficient microcellular system. A proper compromise has to be achieved between spectrum efficiency and bit error rate. The error correction capability of BCH code has a significant effect on the performance for fast multipath fading. However, with slow multipath fading and/or severe shadowing, the effect of error correction is much smaller. Unshadowed fast multipath fading is less harmful than (shadowed or unshadowed) slow multipath fading when appropriate coding is used.