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WO2010062283A1 - Télémétrie dans des réseaux umts - Google Patents

Télémétrie dans des réseaux umts Download PDF

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Publication number
WO2010062283A1
WO2010062283A1 PCT/US2008/083628 US2008083628W WO2010062283A1 WO 2010062283 A1 WO2010062283 A1 WO 2010062283A1 US 2008083628 W US2008083628 W US 2008083628W WO 2010062283 A1 WO2010062283 A1 WO 2010062283A1
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WIPO (PCT)
Prior art keywords
determining
network
marker
downlink
lmu
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Application number
PCT/US2008/083628
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English (en)
Inventor
John P. Carlson
Tariqul Islam
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Commscope Technologies LLC
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Andrew LLC
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Filing date
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Publication of WO2010062283A1 publication Critical patent/WO2010062283A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H04W64/003—Locating users or terminals or network equipment for network management purposes, e.g. mobility management locating network equipment

Definitions

  • wireless communication systems include cellular systems and wireless local area networks, among others.
  • a regulatory body typically licenses a frequency spectrum for a corresponding geographic area (service area) that is used by a licensed system operator to provide wireless service within the service area.
  • a plurality of base stations may be distributed across the service area. Each base station services wireless communications within a respective cell. Each cell may be further subdivided into a plurality of sectors.
  • Typical mobile station location technologies may be classified into external methods or network based methods.
  • An external method is the Global Positioning System ("GPS").
  • Network based methods may be further categorized depending on whether it is the network or the mobile station that performs necessary signal measurements. These signal measurements may involve the reception time of signals communicated between a base station (“BS”) and a mobile station (“MS”), the angle of arriving signals or round trip delay measurements of signals communicated between a serving BS and an MS, or combinations thereof.
  • MSC Mobile Station Controllers
  • BSC Base Station Controllers
  • BTS Base Transceiver Station
  • GSM Global System for Mobile Communications
  • TDMA North American Time Division Multiple Access
  • CDMA Code Division Multiple Access
  • Extensive infrastructures e.g., ANSI-41 or MAP-based networks
  • MLC Mobile Location Center
  • LMC Mobile Location Center
  • LMU Location Measurement Units
  • LMU Location Measurement Units
  • an MSC communicates with a BSC to prompt the BTS (collectively, "BS") to generate paging signals to a specified MS within a defined service area typically known as a cell or sector.
  • the MS upon receiving the page request, responds to indicate that it is present and available to accept an incoming call.
  • the BS upon receiving a page response from the MS, communicates with the MSC to advise it of the same.
  • the call is then routed through the BS to the MS as the call setup is completed and the communication link is created.
  • One well-known method for locating a MS is triangulation.
  • Signal power level or signal timing measurements between the MS and three or more base stations are used to triangulate.
  • the signal power level or signal timing measurements are used to estimate the distance between each base station and the MS.
  • the distances are plotted to determine a point of intersection.
  • the point of intersection is the approximate transmitter location.
  • this method works only when the signal strength is relatively strong and not greatly affected by radio frequency (RF) fading, such as multipath interference common in urban environments.
  • RF fading occurs when radiated signals encounter various obstacles that reflect and diffract the signal causing the received signal power level at the base station and mobile terminal to vary up to 30 dB.
  • RF radio frequency
  • TDOA time difference of arrival
  • E-OTD enhanced observed time difference
  • GPS Global Positioning System
  • DoD U.S. Department of Defense
  • SA Selective Availability
  • GPS systems without SA are limited to an accuracy of approximately 100 meters. Widespread use of the GPS and the decision to discontinue the LORAN-C navigation system convinced the DoD to drop SA thereby allowing commercial GPS receivers to dramatically increase accuracy.
  • the FCC recognized that GPS receivers could be incorporated into mobile phones when it made minor adjustments to the Phase II schedule. Using GPS to report location, however, requires the mobile user to upgrade existing hardware or to purchase new hardware.
  • an embodiment of the present subject matter provides a novel method and system to derive a range estimate by exploiting a measured downlink timing of a serving cell site and combining this with a measured uplink time of arrival.
  • Another embodiment of the present subject matter provides a method for determining an approximate range from an LMU to a mobile device.
  • the method comprises receiving at the LMU an uplink signal from the mobile device, determining an uplink frame marker from the uplink signal, and receiving at the LMU a downlink signal from a base station serving the mobile device.
  • the method further comprises determining a downlink slot marker from the downlink signal, determining a round trip propagation delay based on the uplink frame marker and the downlink slot marker, and determining an approximate range from the LMU to the mobile device as a function of the round trip propagation delay.
  • a communications network for determining an approximate range to a mobile device.
  • the network may comprise an LMU for receiving an uplink signal from a mobile device, circuitry for determining an uplink frame marker from the uplink signal, and a base station serving the mobile device for transmitting a downlink signal to the LMU.
  • the network may further comprise circuitry for determining a downlink slot marker from the downlink signal, circuitry for determining a round trip propagation delay based on the uplink frame marker and the downlink slot marker, and circuitry for determining an approximate range from the LMU to the mobile device as a function of the round trip propagation delay.
  • Figure 1 is an illustration of a wireless communications network according to an embodiment of the present subject matter.
  • Figure 2 is an illustration of the structure of a synchronization channel radio frame according to an embodiment of the present subject matter.
  • Figures 3 A and 3B illustrate examples of detection of downlink slot markers according to embodiments of the present subject matter.
  • Figure 4 is an illustration of the timing relationships between downlink physical channels according to an embodiment of the present subject matter.
  • Figure 5 is an illustration of an example of a non-coherent correlation result having a delay of one slot according to an embodiment of the present subject matter.
  • Figure 6 is an illustration of a folding of the non-coherent correlation result of Figure 5.
  • Figure 7 is an illustration of an estimation of round trip propagation delay according to an embodiment of the present subject matter.
  • Figure 8 is an algorithm according to one embodiment of the present subject matter.
  • FIG. 1 is an illustration of a wireless communications network according to an embodiment of the present subject matter.
  • the network may be a Global System for Mobile Communication (“GSM”) network, a Time Division Multiple Access (“TDMA”) network, Code Division Multiple Access (“CDMA”) network, a UMTS network, a Worldwide Interoperability for Microwave Access (“WiMax”) network, a WiFi network, networks utilizing Evolution-Data Optimized (“EDVO”), CDMA2000 network, 1 times Radio Transmission Technology (“IxRTT”) standards or another equivalent network.
  • GSM Global System for Mobile Communication
  • TDMA Time Division Multiple Access
  • CDMA Code Division Multiple Access
  • WiMax Worldwide Interoperability for Microwave Access
  • WiFi Wireless Fidelity
  • EDVO Evolution-Data Optimized
  • CDMA2000 Code Division Multiple Access
  • IxRTT Radio Transmission Technology
  • LMU Location measurement units
  • the wireless network 100 serves mobile stations or devices 120, 122 within reception range of at least one of the base stations 102-106.
  • Mobile stations 120, 122 may include cellular telephones, text messaging devices, computers, portable computers, vehicle locating devices, vehicle security devices, communication devices, wireless transceivers or other devices with a wireless communications interface.
  • Base station transceivers 102-106 also commonly referred to simply as base stations, are connected to a central entity or central network unit 130.
  • the central entity 130 may be a base station controller ("BSC") in a base station subsystem ("BSS"), a Radio Network Controller ("RNC") in a Radio Access Network (“RAN”), or, for GSM, General Packet Radio Service (“GPRS”) or UMTS system, a serving mobile location center (“SMLC”) or an equivalent.
  • BSC base station controller
  • RNC Radio Network Controller
  • RAN Radio Access Network
  • GSM Global System for Mobile communications
  • GPRS General Packet Radio Service
  • UMTS serving mobile location center
  • SMLC serving mobile location center
  • the connection from each base station to a BSC, SMLC or other central network entity may employ a direct transmission link, e.g., a wired connection, microwave link, Ethernet connection, and the like, or may be employed by one or more intermediate entities, e.g., an intermediate BSC in the case of a connection from a BTS to an SMLC for GSM.
  • Each mobile station 120, 122 may periodically measure the transmission timing difference between pairs of base stations 102-106. For example, a mobile station 120 may measure the difference in transmission timing for communication from its serving base station 102 and from one or more neighboring base stations, e.g., 106 and/or 103. . '
  • the mobile station 120 searches for a cell and determines the downlink scrambling code and frame synchronization of that cell.
  • the cell search is typically carried out in three steps, slot synchronization, frame synchronization and code-group identification, and scrambling-code identification.
  • the mobile station 120 uses a downlink signal commonly referred to as the Synchronization Channel ("SCH").
  • SCH Synchronization Channel
  • Figure 2 is an illustration of the structure of a synchronization channel radio frame according to an embodiment of the present subject matter.
  • the SCH 200 consists of two sub channels, the Primary SCH 210 and the Secondary SCH 220.
  • the Primary and Secondary SCH 210, 220 are divided into fifteen slots 230, each having a length of 2560 chips.
  • the Primary SCH 200 transmits a modulated code having a length of 256 chips and transmits the Primary Synchronization Code ("PSC") 240 (denoted as c p ) once every downlink slot 230.
  • PSC Primary Synchronization Code
  • the PSC 240 is the same for every cell in the system and does not have any complex scrambling thereon.
  • the Secondary SCH 220 consists of repeatedly transmitting a sequence of modulated codes having a length of 256 chips.
  • Secondary Synchronization Codes (“SSC") 250 are transmitted in parallel with the Primary SCH 210.
  • Each SSC 250 may be selected from a set of sixteen different codes having a length of 256 chips.
  • This sequence on the Secondary SCH 220 indicates to which of the code groups a cell's downlink scrambling code belongs.
  • the primary and secondary synchronization codes are modulated by the symbol a shown in Figure 2 indicating the presence/absence of space time block coding based transmit antenna diversity (“STTD") encoding on the Primary Common Control Physical Channel (“P-CCPCH”) and is listed in Table 1 below.
  • STTD space time block coding based transmit antenna diversity
  • P-CCPCH Primary Common Control Physical Channel
  • BCH broadcast channel
  • the mobile station utilizes the SCH's primary synchronization code to acquire slot synchronization to a cell. This is typically done with a single matched filter or any similar device matched to the PSC. The slot timing of the cell may then be obtained by detecting peaks in the matched filter output.
  • the PSC or C psc is constructed as a generalized hierarchical Golay sequence.
  • the PSC generally exhibits good aperiodic auto correlation properties.
  • the PSC may be defined as:
  • the PSC is generated by repeating the sequence a modulated by a Golay complementary sequence and creating a complex-valued sequence with identical real and imaginary components. Once the PSC is known, the PSC may be correlated against the downlink signal to detect the slot marker. In one embodiment of the present subject matter, a slotwise noncoherent addition technique may be applied for higher detection confidence.
  • Figures 3 A and 3B illustrate an exemplary detection of downlink slot markers according to embodiments of the present subject matter. With reference to Figures 3 A and 3B, approximately four slots of downlink samples from a CMU operating in UMTS terrestrial radio access ("UTRA") Band II were collected. The slot markers were detectable using both 256 chip long correlation 310 and 3 -bit noncoherent additions of 256 chip long correlations 320.
  • FIG 4 is an illustration of the timing relationships between downlink physical channels according to an embodiment of the present subject matter.
  • the P-CCPCH 410 on which the cell system frame number ("SFN") is transmitted, is used as the timing reference for all the physical channels, directly for downlink and indirectly for uplink.
  • the Primary SCH 210, the Secondary SCH 220, the Primary and Secondary CPICH 420, and the P-CCPCH 410 all have identical frame timings.
  • the three sectors of a base station are generally locked to a common reference clock or frequency source. Therefore, the relative time differences of the downlink frames of the three sectors are constant, although the reference clock may itself drift.
  • the time difference of the downlink frames in different sectors at the same site is generally a multiple of 256 chips.
  • Table 2 below provides a definition of some synchronization parameters and clarifies the timing relationship of the sectors. The parameters listed in Table 2 are not intended to be an exhaustive list as Section 5 of TS 25.402 provides a more comprehensive list, and thus should not limit the scope of the claimed appended herewith.
  • the mobile station 120 has the capability to follow the frame timing change of the serving site (Node B).
  • the uplink DPCCH/DPDCH frame transmission takes approximately T 0 chips after the reception of the first detected path (in time) of the corresponding downlink DPCCH/DPDCH frame from the reference cell.
  • T 0 is a constant defined to be 1024 chips.
  • the uplink DPCCH/DPDCH frame transmission takes place approximately T 0 chips after the reception of the first detected or significant path (in time) of the corresponding downlink DPCCH/DPDCH or F-DPCH frame.
  • the mobile station initial transmission timing error T 0 is maintained within ⁇ 1.5 chips at the mobile station.
  • the reference point for the mobile station initial transmit timing control requirement is the time when the first detected path (in time) of the corresponding downlink DPCCH/DPDCH frame is received from the reference cell plus T 0 chips.
  • the reference cell is the one the mobile station has in the active set. The cell, which is selected as a reference cell, remains as a reference cell even if other cells are added to the active set.
  • the mobile station adjusts its respective transmit timing no later than the time when the whole active set update message is available at the mobile station.
  • the mobile station is also capable of changing the transmission timing according to the received downlink DPCCH/DPDCH frame.
  • the offsets between the DPCHs of the three sectors of a base station are multiples of 256 chips
  • the offset between the start of DPCH and SCH is a multiple of 256 chips
  • Exemplary LMUs may be collocated with the serving base station.
  • an exemplary LMU monitors a neighboring cells' downlink signals (which transmit the same SCH utilized as reference for correlation)
  • spurious peaks may be seen in the correlation result if the downlink signals of the neighboring sectors are strong.
  • Embodiments of the present subject matter may thus correlate for a delay of 256 chips and then add all correlation results non-coherently to thereby align the DL slot markers of the three collocated sectors.
  • Figure 5 illustrates an exemplary noncoherent correlation result having a delay of one slot according to an embodiment of the present subject matter.
  • a non-coherent correlation result 500 with a delay of 5120 samples i.e., 2560 chips or one slot
  • the circles 510 in the plot indicate 512-sample (256-chip) jumps from the highest peak found.
  • the peaks on the 1st and 8th markers 512, 514 are from the collocated sectors.
  • the two other weak peaks, between 5th and 6th markers 516 and 8th and 9th markers 518, are from the downlink signals of neighboring cells.
  • Figure 6 is an illustration of a folding .of the non-coherent correlation result of Figure 5.
  • a prominent peak 610 may be identified corresponding to only the peak from the collocated site.
  • spurious peaks detected at an exemplary LMU from the downlink signals of neighboring cells 516, 518 may be faded and the DL slot markers for the collocated sectors 512, 514 may be enhanced providing the prominent peak 610 illustrated in Figure 6. Therefore, exemplary embodiments of the present subject matter may thus correlate for a delay of 256 chips and then add all correlation results non-coherently, i.e., folding, to thereby align the DL slot markers of collocated sectors.
  • FIG. 7 is an illustration of an estimation of round trip propagation delay according to an embodiment of the present subject matter.
  • the time stamp of an uplink signal 710 during the reverse collection period 711 is represented as tu L and measured in seconds.
  • the collector thread, at the end of reverse collection period, may tune to the downlink frequency and collect downlink samples and the time stamp for the second collection period 721 may also be noted.
  • the time stamp of a downlink signal 720 during the forward collection period 721 is represented as t DL and measured in seconds.
  • the uplink time of arrival (“UL TOA”) frame marker 712 is measured nm, samples 714 from tm,.
  • the downlink marker 722 (e.g., slot marker folded to 512 samples) is measured n DL samples 724 from t ⁇ L - To estimate the round trip propagation delay 750 (n roundj ri p ), the downlink marker 722 must be shifted.
  • a shifted downlink marker 740 may be shifted a number of samples (n DL sh i ft ) from t DL as represented by the following relationship:
  • n D L_shift (tDL-tuL)R + n DL - 512N (2)
  • n DL shif i 742 represents the number of samples the downlink marker has been shifted from tu L
  • R is a sample rate in Hz
  • N is an integer such that:
  • An exemplary sample rate R may be, but is not limited to 7.68 MHz.
  • round trip propagation delay 750 may be estimated as a function of the following relationship:
  • nround_trip n UL " n DL_shift (4)
  • n round ⁇ p is the round trip propagation delay in samples. It follows that the radius of a corresponding range ring may be estimated as a function of the following relationship:
  • n roundjr i p may not be reliable.
  • the range ring radius will be zero if n roundJ ri p is greater than 500 samples.
  • the range ring is generally applicable for the serving site which governs the mobile station timing.
  • the serving sector identifier (UC-ID) is generally available in the respective network tipping information list. While the DTP interface does not provide this information, the following steps may be taken to resolve such issues: change the DTP-GCS interface to include all of the primary scrambling code with their relative strengths; populate the "Pilot Offset" fields of NMS with the primary scrambling code of the UMTS sectors during DTP based testing; and/or GCS will match the strongest primary scrambling code with the database and will decide which site is the serving one.
  • all the range rings smaller than 1 km may be passed to a processor and the processor will filter and/or determine which range ring to utilize based upon information available thereto, including but not limited to, information arriving through a hybrid combination of location technologies such as triangulation, trilateration, time difference of arrival, GPS, angle of arrival, Cell-ID, signal strength, assisted-GPS, Enhanced Observed Time Difference, Advanced Forward Link Trilateration, etc.
  • range rings may be utilized when one or more sites detect TOA.
  • a range ring solution for GSM generally requires keeping track of network deployment information whereas the solution for UMTS does not require knowledge of network configuration such as base station timing offsets, etc.
  • FIG. 8 is an algorithm according to one embodiment of the present subject matter.
  • a method for determining an approximate range from a LMU to a mobile device is provided.
  • Exemplary communications networks employing an LMU according to embodiments of the present subject matter may be a UMTS network, WiMax network, GSM network, WiFi network, CDMA network or a network utilizing Evolution-Data Optimized ("EDVO"), IS-95, CDMA2000, and/or 1 time Radio Transmission Technology (“IxRTT”) standards.
  • EDVO Evolution-Data Optimized
  • IxRTT 1 time Radio Transmission Technology
  • an uplink signal may be received at the LMU from the mobile device.
  • An exemplary mobile device may be, but is not limited to a cellular telephone, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.
  • an uplink frame marker is determined from the uplink signal.
  • a down link signal from a base station serving the mobile device may be received at the LMU and a downlink slot marker determined from the downlink signal in step 840.
  • the LMU and the serving base station may be co-located.
  • the downlink signal may be from a sector other than the sector serving the mobile device.
  • the downlink slot marker may be, but is not limited to, a modulo 512 multiple. Further, the downlink slot marker may be a function of equation (3) provided above.
  • the round trip propagation delay may be determined in step 850 based upon the uplink frame marker and the downlink slot marker.
  • an approximate range from the LMU to the mobile device may be determined as a function of the round trip propagation delay.
  • the approximate range may be determined as a function of signals received from one or more LMUs installed throughout an exemplary communications network.
  • step 820 may also include determining a first time stamp for the uplink signal and determining a number of samples between the first time stamp and the uplink frame marker.
  • step 820 may also include determining a second time stamp for the downlink signal and determine a number of samples between the second time stamp and the downlink slot marker.
  • the round trip propagation delay may be determined by shifting the downlink slot marker a number of samples such that the number of samples between the uplink frame marker and the downlink slot marker is less than 512, and determining the number of samples between the uplink frame marker and the shifted downlink slot marker.
  • an approximate range may be determined from the LMU to the mobile device by multiplying the number of samples between the uplink frame marker and the shifted downlink slot marker by a predetermined number.
  • the predetermined number may be, but is not limited to, 19.53125.
  • the number of samples between the uplink frame marker and the shifted downlink slot marker may be determined by a non-limiting exemplary sample rate of 7.68 MHz.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L’invention concerne un procédé et un système permettant de déterminer une portée approximative entre une unité de mesure d’emplacement et un dispositif mobile. Un signal de liaison ascendante provenant du dispositif mobile est reçu par l’unité de mesure d’emplacement et un marqueur de trame de liaison ascendante est déterminé à partir du signal de liaison ascendante. Un signal de liaison descendante est reçu au niveau de l’unité de mesure d’emplacement à partir d'un poste de base desservant le dispositif mobile, et un marqueur de fente de liaison descendante est déterminé à partir du signal de liaison descendante. Une temporisation de propagation aller-retour est déterminée sur la base du marqueur de trame de liaison ascendante et du marqueur de fente de liaison descendante, et une portée approximative entre l’unité de mesure d’emplacement et le dispositif mobile est déterminée en fonction de la temporisation de propagation aller-retour.
PCT/US2008/083628 2008-11-14 2008-11-14 Télémétrie dans des réseaux umts Ceased WO2010062283A1 (fr)

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US98420708A 2008-11-14 2008-11-14
US11/984,207 2008-11-14

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040102196A1 (en) * 2001-04-06 2004-05-27 Mikko Weckstrom Location method and system
US20040198394A1 (en) * 2001-12-12 2004-10-07 Jari Syrjarinne Method, apparatus and system for synchronizing a cellular communication system to GPS time
US7110774B1 (en) * 2000-10-27 2006-09-19 Intel Corporation Dual mode uplink/downlink location measurement and multi-protocol location measurement
US20060276202A1 (en) * 2003-07-21 2006-12-07 Mark Moeglein Method and apparatus for creating and using a base station almanac for position determination
US20080248813A1 (en) * 2007-04-06 2008-10-09 Palm, Inc. System and Methods for Obtaining Coarse Location for a Mobile Device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7110774B1 (en) * 2000-10-27 2006-09-19 Intel Corporation Dual mode uplink/downlink location measurement and multi-protocol location measurement
US20040102196A1 (en) * 2001-04-06 2004-05-27 Mikko Weckstrom Location method and system
US20040198394A1 (en) * 2001-12-12 2004-10-07 Jari Syrjarinne Method, apparatus and system for synchronizing a cellular communication system to GPS time
US20060276202A1 (en) * 2003-07-21 2006-12-07 Mark Moeglein Method and apparatus for creating and using a base station almanac for position determination
US20080248813A1 (en) * 2007-04-06 2008-10-09 Palm, Inc. System and Methods for Obtaining Coarse Location for a Mobile Device

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