One of the most important capacity parameters in the DS-CDMA cellular systems is the system reliability on which the reverse link capacity is usually limited by a prescribed lower bound. In this letter, the effect of the system reliability as well as imperfection of the power control on the system capacity is quantitatively considered using sensitivity analysis in a multimedia DS-CDMA cellular system. As a result, an analytical close-form formula is presented in terms of the standard deviation of the received SIR and the system reliability. In a numerical example, sensitivity with respect to the system reliability on the system capacity has the value ranging from 5 to 50 between 95% and 99% the range in we are interested.

In this paper, the capacity is analyzed for a CDMA system supporting heterogeneous traffic with on/off activity. The capacity is analyzed by modeling the on/off traffic activity as a binomial random variable and compared to the conventional analysis with the simplified traffic activity factor which is a constant. It has been shown that the capacity with the conventional analysis is more optimistic than the capacity analyzed with the binomial modeling of traffic activity. The effect of traffic activity on the capacity is further investigated for two different cases. One is the case under the same transmission rate where the average rate changes according to the traffic activity. The other is the case under the same average rate where the transmission rate changes according to the traffic activity. As the traffic activity factor becomes larger, the capacity increases for the case under the same average rate, whereas it decreases for the case under the same transmission rate.

This paper investigates the turbo equalization techniques for wireless cellular systems. Simulation results over three GSM channel models are presented.

In this letter, a resource allocation scheme is proposed to efficiently utilize the resource of CDMA systems with respect to the throughput. When we let the throughput be a function of various data rates for multimedia traffics, the scheme is to find the optimum set of data rates for concurrent user groups with which we can achieve the maximum throughput. It is also shown that the optimum data rate set always includes one non-trivial rate while all the others keep the minimum required data rate.