Alternative DS-CDMA Architectures for Voice/Data Applications with Best Base Station Assignment

This paper analyzes the uplink behavior of the multicode and variable spreading factor DS-CDMA systems that accommodate users with different transmission rate requirements in a multicell mobile radio system. It takes into account the possibility of a portable to choose the least interfered among N c nearest base stations, imperfect power control on slow signal fluctuations resulting from shadowing and random location of the users. System capacity is determined analytically, employing two distinct approximations featuring low computational costs, and by simulation. It is shown that having the portable controlled by the least interfered base produces a remarkable improvement on the performance of both classes of users and that either architecture (multicode or variable spreading factor) can favor voice or data applications through a suitable tuning of system parameters. Moreover, the simulation approach allows to assess the accuracy of the analytical approximations for an interesting range of system parameters.