Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/0278—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves involving statistical or probabilistic considerations

Definitions

• the present invention relates to a method for locating a mobile terminal with respect to a building in an operational digital cellular radio network. More particularly, it relates to a location of a mobile terminal inside or outside a building, or inside a moving vehicle.
• the location of a mobile terminal in relation to a building is particularly useful for optimizing the radio resources of cellular radiocommunication and more precisely to the optimization of the positioning of base stations inside buildings.
• the aim of the invention is to locate a mobile terminal inside or outside a building by using standardized magnitudes of radio interfaces of cellular radio networks.
• a method for locating a mobile terminal with respect to a building in an operational radio network according to which N respective magnitudes measured between the mobile terminal and N base stations are transmitted at K instants from the mobile terminal.
• a localization device DL
• N and K being predetermined integers
• it comprises the following steps in the localization device: at each of the K instants, order the N magnitudes to extract a best size and one of the N magnitudes, and estimating two probability densities of said one magnitude based on the best size knowing that the mobile terminal is inside and outside the building, determining a density ratio between the product of the probability densities determined at all times knowing that the mobile terminal is inside the building on the produces determined probability densities at all times knowing that the mobile terminal is outside the building, and comparing the density ratio to a first predetermined threshold in order to locate the terminal movable within the building when the ratio is greater than the first predetermined threshold and outside the building when the ratio is less than or equal to the first predetermined threshold.
• an advantage of the invention is also to be able to locate the mobile terminal inside or outside a moving vehicle.
• the method also comprises X steps of determining density ratios at X instants with all K instants preceding the instant in question, X being a predetermined integer, and a step of determining signs of the differences between the ratios. at X times and a second threshold, knowing that the mobile terminal is not inside the building during the X moments, in order to locate the mobile terminal inside a moving vehicle when the number of change of signs of the differences is at least greater than a predetermined number.
• the invention also relates to a device for locating a mobile terminal with respect to a building in an operational radiocommunication network, so as to implement the method of the invention.
• the device is characterized in that it comprises: a means for ordering, at each of the K instants, the N magnitudes in order to extract a better quantity and one of the N magnitudes, and a means for estimating, at each of K moments, two probability densities of said one magnitude as a function of the better knowing that the mobile terminal is inside and outside the building, a means for determining a density ratio between the product of the determined probability densities at all times knowing that the mobile terminal is inside.
• the density ratio to a first predetermined threshold in order to locate the mobile terminal at the interior of the building when the ratio is greater than the first predetermined threshold and outside the building when the ratio is less than or equal to the first predetermined threshold.
• the invention relates to a computer program adapted to be implemented in a localization device according to the invention.
• the program includes program instructions which, when the program is loaded and executed on said server, perform the steps of the localization method according to the invention.
• FIG. 1 is a schematic block diagram of a system for locating a mobile terminal with respect to a building
• FIG. 2 is a schematic block diagram of a variant of the location system; and - Figure 3 is an algorithm of the method of locating a mobile terminal with respect to a building according to the invention.
• FIG. 1 shows functional means included in a positioning system of a mobile terminal for implementing the location method according to the invention in a digital cellular radiocommunication network RR.
• the location system mainly comprises a location device DL including in particular a central unit UC, a probability density determination module MDD, a location module ML and a simulator SI.
• the mobile terminal TM is a conventional mobile cellular radio terminal and can also be a device or obj and mobile telecommunications electronics, for example a personal digital assistant communicating PDA or a laptop.
• the mobile terminal TM is adapted to the type of network RR, for example GSM, AMPS, GPRS or EDGE, or CDMA (Coded Division Multiple Access) according to the third generation (3GPP) of networks of the UMTS type.
• 3GPP Third Generation
• a given base station Bi is located in the vicinity of NI neighboring base stations Bj with indices i, j such that i, je ⁇ 1, N ⁇ and j ⁇ i.
• a base station Bj is said to be adjacent to the given base station Bi when the neighboring base station Bj is situated in a predetermined radius around the given base station Bi, and the given base station Bi receives an interference power.
• a mobile situated at the station Bj such as the Carrier-to-Interference Ratio (CIR) in the station given Bi is greater than a predetermined minimum interference signal ratio.
• CIR Carrier-to-Interference Ratio
• the number NI of neighboring stations thus varies from one station to another in dependence on the topography of the terrain surrounding the given station Bi and can be of the order of 2 to some tens.
• the locating device DL is included in the fixed part of the cellular radiocommunication network RR, for example of the UMTS type. It is connected to terrestrial Iub interfaces between RNC (Radio Network Controller) base station controllers and the base stations served by these controllers, so as to collect the quantities specified hereinafter transmitted periodically in signaling channels by the controllers. mobile terminals having active links with the served base stations.
• RNC Radio Network Controller
• the location device is connected to a maintenance center OMC (Operation and Maintenance Center). Quantities measured between the mobile TM and the base stations are reported to the OMC maintenance center through the RNC base station controllers in the RR network.
• OMC Operaation and Maintenance Center
• the N base stations likely to communicate with the mobile terminal TM are located outside buildings BU.
• Base stations are considered to be situated in urban areas which are highly wished by telecommunications operators and for which the object of the invention is to be achieved.
• Standard quantities necessary for implementing the location method are transmitted by equipment of the RR radio network to the location device DL.
• the quantities transmitted come from data exchanges between the mobile terminal TM and the given base station Bi and data exchanges between the mobile terminal TM and the N - I neighboring base stations Bj. Therefore, N variables Gi to GN are transmitted.
• the locating method according to the invention can be implemented with different types of quantities generally depending on the characteristics of the RR radio network.
• the quantities transmitted from the mobile terminal TM to the location device DL are receiving powers or estimates of the radio quality of signals which are transmitted in downlinks by the N base stations respectively and received by the mobile terminal TM; the receiving powers or the radio quality estimates measured in the mobile terminal TM are transmitted periodically on an uplink to the given base station Bi.
• a magnitude Transmitted is the normalized parameter "RXLEV" indicating the received signal field level among 64 levels.
• the RR radio network is of the UMTS type and a transmitted quantity is an attenuation (pathloss) derived from a received power measured in the common beacon channel on the CPICH RSCP downlink.
• a power ratio of a chip measured on a power spectral density in a useful band is a power ratio of a chip measured on a power spectral density in a useful band.
• the method for locating a mobile terminal TM mainly comprises seven steps E1 to E7, as shown in FIG.
• the locating device DL receives the respective N variables Gi to GN transmitted at K periodic times, K being a predetermined integer. For example, for the GSM K is equal to 120 for a duration of observation of one minute, when the measurement rise period is equal to 0.5 seconds.
• the central unit UC orders the N magnitudes Gi to GN in descending order of a better magnitude GM at a worse magnitude, in step E1.
• the central unit UC extracts the best size GM and one G n of N magnitudes, in step E2.
• the extracted quantity G n is chosen according to a predetermined rank r in the ordered list of N ordered quantities, with r G ⁇ 1, N ⁇ , and is denoted by G r .
• Rank r is identical and valid for all K instants. For example, the rank r is equal to 3 and the number N is at most equal to 10.
• ordination depends on the nature of magnitudes. For example, when the quantities are powers, the highest magnitude corresponds to the best GM magnitude. In another example, when the magnitudes are ratios such as attenuations always greater than 1, the smallest magnitude may correspond to the best magnitude GM -
• the probability density determination module MDD estimates two probability densities of the extracted size G r as a function of the best quantity GM, knowing that the mobile terminal TM is inside and at the same time. outside the building BU, at step E3.
• the probability densities of said magnitude G r knowing that the mobile terminal TM is inside (I) or outside the BU building at a time k are noted respectively P [G ⁇ I) and P [G ⁇ E).
• the estimation of the two densities at K instants depends on correspondences between couples of a better magnitude and a magnitude extracted and probability densities knowing that a mobile terminal is inside and outside a building, established by the SI simulator during a pre - simulation. The simulation is performed previously by radio coverage prediction software or mobile network simulation software.
• step E5 the locating module ML compares the density ratio with a first predetermined threshold Si in order to locate the mobile terminal TM inside the building when the ratio is greater than the first predetermined threshold and outside the building. building when the ratio is less than or equal to the first predetermined threshold.
• the steps E1-E5 are executed at each of the instants to determine a density ratio as a function of K probability densities P (GV
• the mobile terminal TM is located at each of the K instants.
• an advantage of the locating method according to the invention is to locate a mobile terminal TM inside or outside a VE vehicle in motion.
• the determination module MDD determines ratios of densities at X instants with all K instants preceding the instant considered, X being a predetermined integer. For example, X equals 6 when K equals 60 seconds.
• step E6 the determination module MDD determines signs of the differences between the density ratios at X times and a second threshold S2, when the mobile terminal TM is located outside the building during the X moments according to the results. from X previous steps E5.
• the number of change of signs of the differences NC is at least greater than a number predetermined change of sign S3
• the locating module ML locates the mobile terminal TM outside a building and inside a VE moving vehicle, in step E7.
• the predetermined number S3 is 2 or 3 when X is 6 and K is 60.
• the first and second thresholds S1 and S2 are identical.
• the invention described herein relates to a method and a system for locating a mobile terminal TM with respect to a building BU.
• the steps of the method are determined by the instructions of a localization program of a mobile terminal TM incorporated in a computing device such as the localization device DL.
• the program comprises program instructions which, when said program is loaded and executed in the localization device whose operation is then controlled by the execution of the program, carry out the steps of the method according to the invention.
• the invention is also applicable to a computer program, especially a computer program on or in an information carrier, adapted to implement the invention.
• This program can use any programming language and be in the form of source code, obj code, and intermediate code between source code and obj code and such as in a partially compiled form, or in any other desirable form for implementing a method according to the invention.
• the information carrier may be any device or entity capable of storing the program.
• the medium may have a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or a magnetic recording means, for example a floppy disk or a hard disk.
• the information medium may be a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by other means.
• the program according to the invention may in particular be downloaded on an internet type network.
• the information carrier may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in carrying out the method according to the invention.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Probability & Statistics with Applications (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2004
  • 2004-12-06 FR FR0412980A patent/FR2879067A1/fr not_active Withdrawn
• 2005
  • 2005-11-30 EP EP05818940A patent/EP1820365A1/de not_active Withdrawn
  • 2005-11-30 WO PCT/FR2005/051013 patent/WO2006067339A1/fr active Application Filing

Non-Patent Citations (1)

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