In this paper, CAC (Call Admission Control) algorithms where decisions are based on total received power for the reverse link in CDMA systems with multiple types of services are proposed. The proposed CAC schemes have advantages in that they have control over the cell load dynamically and guarantee the required SIR, that is, QoS (quality of service). The optimal ratio of required transmission power that achieves the maximum capacity is derived for evaluating the cell load and SIR (signal to interference ratio) reflected in total received power at base stations. Allocation of different thresholds can be made for different services which can be regarded as priority based schemes. Two types of services, voice and data, are considered and the maximum throughput is obtained when threshold values are the same. In addition, the transmitter removal scheme is adopted that eliminates calls when the system does not meet the required SIR. Simulation results are provided to evaluate the performance.

In this paper, we present several traffic handling schemes for improving the QoSs (quality-of-services) in a micro-cell based PCS (personal communication services) network. Traffic handling schemes are devised for the efficient use of the limited radio resources with the increasing number of users and multimedia traffic. Both mathematical analysis and computer simulations are carried out for the performance evaluation in terms of the blocking probability of new call, the forced termination probability of handoff voice and data and the average delay of data. Analytical models by bivariate Markov processes are provided. It reveals that a finite queueing scheme for handoff delay sensitive data guarantees QoS metrics, such as the blocking probability of new voice and data and forced termination probability of handoff voice and data, as well as the efficient use of radio resources. The optimal number of reserved channels for handoff delay sensitive data and the optimal number of reserved channels for handoff traffic (in reserved channel scheme) are investigated and obtained. Dynamically controlled reserved channel schemes turn out to provide no significant performance improvement.

We observe the inter-carrier interference (ICI) caused by channel variation of the fading in time domain in orthogonal frequency division multiplexing (OFDM) systems. This observation allows us to propose simple two-stage equalizer to minimize the ICI. Simulation results show that the bit error rate (BER) performance of the proposed equalizer with much reduced complexity is comparable with that of the classical frequency domain linear minimum mean squared error (MMSE) equalizer.

In this paper, downlink performance of multicarrier CDMA (MC-CDMA) systems under correlated fading channels is analytically investigated. Under code hopping, a signal to interference plus noise ratio (SINR) and bit error rate (BER) performance are derived in multi-cell environments. In addition, specific conditions to validate the commonly used Gaussian approximation of an interference plus noise distribution in MC-CDMA systems are discussed. It is proved that the approximation is adequate in case of low correlation between subcarriers and a large spreading factor (SF). The proposition is confirmed through comparison between analytical and simulation results.