We address the radio resource management problem in high altitude platform stations (HAPS) systems. We propose a centralized resource allocation strategy, named ORA-LF, that allows maximizing the system throughput while preserving the fairness among mobile terminals carrying the same traffic type. We also describe a simplified procedure, named SRA-LF, that allows making the ORA-LF strategy compatible with real time implementations.

This paper envisages a cellular system based on code-division multiple access and investigates the performance of a strength-based closed-loop power control (CLPC) scheme on the basis of different parameters, such as the number of bits of the power command, the quantization step size, and the user speed. On the basis of a log-linear CLPC model, an analytical approach has been developed that has allowed to determine the optimum quantization step size to be used for each value of the number of power command bits. Simulation results have permitted to support the analytical framework developed in this paper.

Future wireless systems will allow the mobile access to multimedia services. This paper proposes a medium access control (MAC) protocol that permits an efficient integration of real time-variable bit rate (rt-VBR) traffic and bursty available bit rate (ABR) traffic. This scheme, named minislotted-dynamic resource assignment (M-DRA), provides rt-VBR sources with a quality of service independent of the ABR traffic load. The M-DRA scheme effectiveness has been validated by comparisons with other protocols.

This paper proposes an analytical study which aims at evaluating the received power statistics in DS-CDMA cellular systems which use a closed-loop power control scheme to compensate for fast multipath fading. The effects of a limited transmission power at the mobile terminals have been also investigated. This study is based on a first order Taylor expansion of the fast fading fluctuations. The accuracy of the obtained results has been verified through computer simulations. Classical frequency-selective channel models have been taken into account which involve the use of a diversity RAKE receiver at the base station. Finally, the system capacity is evaluated under different environmental conditions.

This paper envisages data transmissions in a low-mobility wireless local area network based on a DS-CDMA air interface. A Rayleigh fading channel and suitable Internet-like traffic model have been envisaged to study the impact of the closed-loop power control on an adaptive coding scheme. The following quality of service (QoS) parameters have been considered in this study: the mean datagram transmission delay and the mean transmission energy per useful bit. We have obtained that our proposed adaptive coding scheme permits one to avoid the use of closed-loop fast power control. Such choice permits one to improve both previous QoS parameters, so allowing an efficient management of radio resources.