We develop a mathematical model to analyze call-level performance of radio channel allocation of TD-CDMA systems supporting multitype heterogeneous and asymmetrical traffic. The mathematical model has multidimensional operations using random vectors or matrices to deal with multiple types of traffic and asymmetrical up-and-down transmission directions separately. Employing the mathematical model, we obtain call blocking probability for each type of traffic and the optimum time-slot switching-point with the smallest call blocking probability.