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39.1 Metropolitan Beacon System (MBS)
ОглавлениеThe MBS belongs to the class of downlink broadcast terrestrial system. In the context of Third Generation Public Partnership (3gpp) standards, a class of locations systems termed Terrestrial Beacon Systems (TBS) has been defined of which MBS is considered an instantiation. The system aims to provide radio signals that can be used to locate the position of the receiver in indoor and dense urban areas where GPS availability is limited. While the system is intended to be complementary to GPS, the system can also be deployed so that the UE can use only MBS signals for position location.
The MBS beacon network is a network of low‐cost, highly synchronized beacons. The network is purpose‐built for positioning, achieving a good geometry of beacons for a receiver anywhere in the network. Network planning and design are done in such a way as to overcome the near‐far problem common to terrestrial systems. In addition, the signal design is done in a manner that facilitates multipath resolution. In order to facilitate accurate altitude estimation, the MBS network also utilizes differential barometric techniques to determine altitude precisely.
The MBS beacons transmit all the information required for trilateration as part of the MBS signal, which allows receivers to estimate 3D position without the need for additional external information. The information may be encrypted to control access and prevent unauthorized usage of the signal.