Showing papers by "Romano Fantacci published in 1994"
TL;DR: The performance of the novel DCA technique in terms of call blocking probability has been derived by simulations and results are compared with those achieved by a fixed channel allocation (FCA) technique to show a better behaviour.
Abstract: This paper deals with an efficient dynamic channel allocation (DCA) technique suitable for applications in mobile satellite cellular networks. A cost function is defined to allow an optimum selection of channels to be allocated on demand. A mobility model suitable for low earth orbit (LEO) satellite systems is presented. The performance of the novel DCA technique in terms of call blocking probability has been derived by simulations. The obtained results are compared with those achieved by a fixed channel allocation (FCA) technique to show a better behaviour.
31 citations
27 Sep 1994
TL;DR: In this paper, a dynamic channel allocation (DCA) technique based on an energy function whose minimization can be performed by a Hopfield neural network was proposed, and the performance of the proposed DCA technique was derived by computer simulations.
Abstract: The interest in global spectrum allocation techniques is growing with the always increasing spectrum demand for mobile communications. This paper deals with a dynamic channel allocation (DCA) technique based on an energy function whose minimization can be performed by a Hopfield neural network. The performance of the proposed DCA technique is derived by computer simulations. Comparisons with a classical FCA technique and a previously proposed DCA technique are given to highlight the better performance of our DCA technique. >
13 citations
TL;DR: The proposed protocols performed better than previously described techniques, especially under poor channel conditions, and the use of noncoherent detection produced a considerable reduction in receiver implementation complexity.
Abstract: This paper presents some generalized error control techniques that allows one to fulfill the delay and reliability demands of applications over integrated service packet networks (ISPNs). Binary frequency shift keying (FSK) modulation, which is suitable for lightwave packet networks and which, in addition, allows noncoherent detection in place of the classical coherent detection, has been considered. Performance is derived in terms of region-by-region and end-to-end error control. The proposed protocols performed better than previously described techniques, especially under poor channel conditions. In addition, the use of noncoherent detection produced a considerable reduction in receiver implementation complexity. >
8 citations
TL;DR: The main goal is to analyze how the increased interference level, typical of a multipath environment, can influence different demodulator architectures in different propagation condi- tions.
Abstract: This paper deals with the modeling and performance evaluation of different Code Divi- sion Multiple Access schemes suitable for applications in terrestrial and satellite mobile cornrnu- nication networks. The use of particular propagation channel models and the relative sensitivity of different demodulation schemes to their parameters are the subject the paper is focused on. In par- ticular, an extension to the case of wideband communications of Lutz's satellite channel model is presented. The main goal is to analyze how the increased interference level, typical of a multipath environment, can influence different demodulator architectures in different propagation condi- tions. Perfectly coherent and differential modulation methods are employed with conventional and RAKE receivers to derive the error rate performance by computer simulations. Some issues con- cerning the characterization of the propagation channel models in the case of the RAKE receiver are also investigated and discussed.
5 citations
TL;DR: Different alternatives for the up-link access technique and for the architecture of the onboard switching fabric are considered and an efficient time division multiple access technique with slots assigned on demand and a novel switching approach are proposed.
Abstract: This paper is focused on a satellite communication system having on-board fast packet switching capabilities. Different alternatives for the up-link access technique and for the architecture of the onboard switching fabric are considered. In particular an efficient time division multiple access technique with slots assigned on demand and a novel switching approach are proposed. Performances in terms of mean access delay and mean on-board switching delay are derived by analytical approaches and computer simulations.
3 citations
TL;DR: The authors propose a new fast packet switching fabric with input shared buffers, where a neural network of the Hopfield type is used to take optimum decisions for switching packets and improve the switching performance.
Abstract: The authors propose a new fast packet switching fabric with input shared buffers, where a neural network of the Hopfield type is used to take optimum decisions for switching packets and improve the switching performance.
1 citations
04 Jul 1994
TL;DR: The main goal is to analyze how the increased interference level, typical of a multipath environment, can influence different demodulator architectures in different propagation conditions.
Abstract: The paper deals with the modeling and performance evaluation of different code division multiple access schemes suitable for applications in terrestrial and satellite mobile communication networks. The paper is focused on the use of particular propagation channel models and the relative sensitivity of different demodulation schemes to their parameters. The main goal is to analyze how the increased interference level, typical of a multipath environment, can influence different demodulator architectures in different propagation conditions. Some issues concerning the characterization of the propagation channel models in the case of the RAKE receiver are also investigated and discussed. >
1 citations
01 Aug 1994
TL;DR: A discrete traffic analysis of a star-topology communication network is presented and first-in/first-out and random policies are examined for selection of messages to be routed from inputs to outputs of the central hub.
Abstract: A discrete traffic analysis of a star-topology communication network is presented. Fast switching capabilities are assumed in the central hub. The communication network is modelled as a discrete queueing system. First-in/first-out (FIFO) and random (RND) policies are examined for selection of messages to be routed from inputs to outputs of the central hub. The case of an infinite number of users is also considered to provide a tight upper-bound on actual performance.
1 citations
28 Nov 1994
TL;DR: The search for an effective channel allocation technique along with the attempt to lower the computational costs of the algorithm which performs such a technique, was the aim of this research.
Abstract: The increasing demand of new services in the field of radio-mobile communications is in contrast with the capacity constraints imposed by the present communications medias. For this reason the use of techniques capable of ensuring that the spectrum assigned to mobile communications will be better exploited, is gaining an ever increasing importance. The search for an effective channel allocation technique along with the attempt to lower the computational costs of the algorithm which performs such a technique, was the aim to be achieved in our research.