PERFORMANCE EVALUATION OF MULTICELL DIRECT-SEQUENCE MICROCELLULAR SYSTEMS

The performance of an asynchronous multi-cell Direct-Sequence Spread S pectrum Multiple-Access (DS/SSMA) system is evaluated in lineal microc ells with flat Rician fading and shadowing. Both the Bit Error Rate (B ER) of the uplink (i.e., the user to the base station) and the downlin k (i.e., the base station to the user) are evaluated. We develop a new analytical model to evaluate the uplink performance which accounts fo r the user's spatial distribution, the chip waveform, the power contro l, and macro-selection diversity. On the downlink, since no power cont rol is used, the desired signal follows a composite log-normal noncent ral chi-square distribution. We propose an approximation method to red uce the computational complexity while still providing satisfactory pr ecision. The analysis results show that the macro-selection diversity can reduce the other-cell interference effectively even for a channel with heavy shadowing. The Rician factor, the standard deviation of the shadowing, and the chip waveform have significant influence on the pe rformance.