To date, the remarkable development of positioning systems has led to the emergence of multiple applications ranging from car navigation, innovative systems of human activity recognition, up to the optimization of power control mechanisms or handover in mobile networks. In this sense, mobile telephony has emerged as a leading exponent of positioning technology, more so since the advent of smartphones. Already with UMTS, techniques such as A-GPS, cell_ID or OTDOA supported a location capability which has been taken into account by FCC. This agency has adopted specific regulations for emergency calls and, as expected, set as mandatory the capability to identify the terminal position by the network operator.
In this context, the continuous improvement of positioning systems is obvious, as well as the development of the 4G mobile telephony, LTE and LTE-Advanced, has relied heavily on these systems, not only because of the potential related to the user applications but also due to the optimization capability that can be achieved in the network itself. In this regard, since its first revision (Release 8), LTE incorporates various localization methods, several of which are already inherited from 3G with specific improvements. We can highlight network-assisted global positioning systems (A-GNSS), enhanced cell identification (eCell ID) or OTDOA, not forgetting the potential that can be achieved through the application of hybrid techniques on the terminal which combine independent results provided by the above techniques.
Both Release 9 and 10, the LTE frame has evolved to support an effective estimation of the terminal position, this effort is still open, as derived from the fact that the 3GPP is considering additional techniques to increase the accuracy indoors or in complex urban environments where, until now, noticeable limitations have been found.
As a complement to all the above techniques, the trend towards a purely heterogeneous LTE network architecture based on different cell sizes will provide greater segmentation that can and will be used also for a more precise location. In short, it becomes clear that LTE will give new impetus to the field of positioning and location systems and their associated applications. In this sense, Gradiant, aware of the enormous potential of this technology remains open at present several research lines related to both LTE and positioning.
