Study on an asynchronous CDMA satellite system for personal communications

Personal communications via satellite are presently assuming a growing interest also in the light of promising applications such as the closed user networks and the integration with terrestrial systems. The present research trend in personal communications is towards systems that, on the one hand, guarantee the maximum flexibility and the maximum exploitation of the scarce available band and, on the other hand, have a decentralized control whose advantages are largely highlighted in the literature. These are, in general, contrasting requirements since the decentralization of the control can entail a loss in flexibility and in efficiency caused by the partition of the resources among the entities charged for the control. The paper shows how the asynchronous CDMA technique can cope with the aforementioned problem and stresses the advantages inherent in the use of this technique. The various CDMA issues are applied to the L-band land mobile payload. In particular, the capacity of the satellite system achievable by using this payload is determined