Israel Martín-Escalona

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Hybrid location systems overcome some of the limitations of location techniques when they are used as standalone. Coverage and accuracy improve when hybridization is carried out by combining time measurements prior to determining location co-ordinates, rather than mixing position co-ordinates. However, for the best performance, certain hybridization methods(More)
The design of telecommunication networks usually comprises three major phases. First, mathematical analysis is carried out and numerical results obtained. During this phase, simple models are used to facilitate calculations. These simple models involve hypotheses that are not realistic, leading to rough performance figures that are valid only as a first(More)
This paper presents a positioning algorithm, named time of arrival to time difference of arrival (TOAD), which computes timedifference-of-arrival (TDOA) measurements from the messages that time-of-arrival (TOA) stations in sight exchange while their positioning processes are running. This study addresses the accuracy of the TOAD algorithm in two different(More)
1 This research work has been funded by the European Commission through IST Project EMILY IST-2000-26040 and the Spanish Government through CICYT project TIC2000-1041-C03-01. Abstract This paper shows the need to transmit extra assistance data in hybrid location systems. The proposal presented here uses the current network protocols in order to deliver(More)
This paper presents an analysis of teletraffic variables in cellular networks. The variables studied are the time between two consecutive handoff arrivals and the handoff delay. These teletraffic variables are characterized by means of an advanced software simulator that models several scenarios assuming Fixed Channel Allocation. Information about the(More)
This work presents a statistical field study of the availability of time sources for location in a true wireless network. Terrestrial (base stations) and satellite (GPS) sources were investigated in three different urban scenarios. The density function of a specific number of sources available for triangulation is presented along with other statistical data(More)