JP4593635B2 - Radio control station and mobile communication system for positioning - Google Patents

Description

  The present invention relates to a mobile communication system and a radio control station, and more particularly to a radio control station and a mobile communication apparatus that perform positioning of a mobile communication apparatus in a mobile communication system.

  In general, a mobile radio communication system includes a mobile communication device owned by a subscriber, a plurality of radio base stations with which the mobile communication device establishes connection, and a radio control station that controls mobile communication of the radio base station. Each radio base station can establish a connection with a mobile communication terminal in a predetermined area, and this predetermined area is called a cell.

  When a subscriber moves with a mobile communication device and moves from one cell to another cell, the mobile communication device needs to move the connection destination from one radio base station to another radio base station. . Such connection conversion (handover) is automatically performed by the radio control station. Therefore, the radio control station needs to know the position of the mobile communication device in the system.

  As a method of measuring the position of the mobile communication device, the distance from the base station is calculated based on the time taken to propagate the radio wave between the mobile communication terminal (mobile station) and the base station and the radio control station. A method for positioning a mobile communication terminal is known. This is a positioning method using a round trip time (RTT) schematically shown in FIGS. More specifically, a base station transmission / reception time difference (base station RTT) in which a time difference between a radio base station transmitting a downlink signal to a mobile station and receiving an uplink signal from the mobile station is measured by the base station, Positioning is performed by calculating a difference from a mobile station reception / transmission time difference (mobile station RTT) obtained by measuring the time difference between receiving a downlink signal from the station and transmitting the uplink signal to the base station.

  Patent Document 1 discloses a method for measuring the position of a mobile communication terminal using RTT.

  In FIG. 1, a radio control station 501 transmits and receives signals between a mobile communication terminal (mobile station) 502 and a radio base station 503 to measure RTT. The radio control station 501 transmits the RTT (mobile station RTT) of the mobile station 502 and the RTT (base station RTT) measurement instruction of the radio base station 503 together with the number of RTT reports and the RTT report period. The radio wave propagation time is calculated from the RTT measurement result. More specifically, in order to calculate the radio wave propagation time, it is necessary to obtain a difference between the measurement result of the base station RTT and the measurement result of the mobile station RTT. There arises a problem of how to associate the mobile station RTT measurement results with each other to obtain the difference.

  As a solution to this, generally, as shown in FIG. 2 and FIG. 3, the measurement results of the base station RTT of each radio base station are given numbers from 1 in the order of reception. Numbers from 1 are added to the mobile station RTT measurement results from the stations in the order of reception. Then, among the base station RTT of the base station A and the mobile station RTT of the mobile station A in FIG. 3, the radio base station and the mobile station RTT measurement results are combined so that the RTT measurement results having the same assigned numbers are combined. It is conceivable to combine the first to fifth and calculate the radio wave propagation time by obtaining the difference between the RTT measurement result reports.

  For example, taking the first RTT measurement result of FIG. 3 as an example, the radio wave propagation time is calculated by obtaining the difference between the base station RTT measurement result of the radio base station A and the mobile station RTT measurement result of the mobile station. It will be. However, the mobile station 502 moves during the RTT measurement of FIG. 2 and a radio link under the new radio base station B (FIG. 2) is added by handover, so that the radio control station 501 is connected to the base station RTT of the new radio base station B. When the measurement is instructed, it is necessary to obtain a difference between the base station RTT measurement result of the radio base station B and the mobile station RTT measurement result of the mobile station.

JP 2006-71389 A (abstract, paragraph [0012])

  When the mobile station 502 establishes a radio link with a new base station by handover, the base station RTT measurement result report of the new radio base station is also given a number in the order received. That is, the first base station RTT measurement result of the radio base station B is reported in the same cycle as the third result report of the base station RTT measurement of the radio base station A and the mobile station RTT measurement of the mobile station. Since this is the first RTT measurement for the base station B that measures the station RTT, it is recognized as the first base station RTT measurement result. On the other hand, when the mobile station 502 measures the RTT of the signal transmission / reception time difference with the base station B for the first time, the mobile station 502 has already measured the RTT of the signal reception / transmission time difference with the base station A twice. It is recognized that the first RTT measurement result with B corresponds to the third RTT measurement result with base station A.

  As a result, the first and second measurement results of the base station RTT measured by the new radio base station B in FIG. 3 are not used. This is because when the first measurement of the base station RTT of the base station B is reported, the first measurement of the base station A and the mobile station has already been completed. In general, when a radio base station is newly added after the xth mobile station RTT measurement, the base station RTT measurement result of the new radio base station before the xth time cannot be used.

  As another problem, in the calculation of the difference in FIG. 3, the radio wave propagation time is obtained by obtaining the difference between the third time of the mobile station RTT measurement result of the mobile station and the third time of the base station RTT measurement result of the radio base station B. In the case of calculation, the time when the third base station RTT measurement is performed and the time when the third mobile station RTT measurement is performed are temporally separated by 2 RTT measurement reporting periods. Therefore, there is a possibility that the wireless environment at the time when the third base station RTT measurement of the wireless base station B is changed from the time when the third mobile station RTT measurement is performed. Therefore, when the difference between the RTT measurement results obtained therefrom is used, the radio wave propagation time cannot be calculated with high accuracy, and the accuracy of position estimation may deteriorate.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a radio control station that calculates radio wave propagation time with high accuracy and a mobile communication system including the radio control station.

In order to achieve such an object, the present invention is included in a mobile communication system including at least one mobile station and at least one radio base station, and the mobile station A radio control station that controls communication between the radio base station and the radio base station, wherein the radio control station is a time from when the radio base station transmits a downlink signal to the mobile station and when an uplink signal is received from the mobile station The base station RTT (Round Trip Time) , which is a value obtained by measuring the base station transmission / reception time difference at the radio base station, is measured and reported to the radio base station together with the number of base station RTT reports and the base station RTT report cycle. indicated, the mobile station reports to measure the mobile station RTT mobile station transceiver Jikan difference is a value measured by the mobile station before sending an uplink signal to the received radio base station a downlink signal from the radio base station , Mobile station RT Movement indicated with reporting period of the same mobile station RTT and the report frequency and reporting period of the base station RTT to the mobile station, the mobile station, when kicking receiving an indication of the mobile station RTT measurement reports from a radio control station, which is indicated The mobile station RTT is measured every reporting period of the designated mobile station RTT, and the measured mobile station RTT is reported to the radio control station, and the radio base station transmits the base station RTT from the radio control station. When the measurement results affect the synchronization instruction reports only report the number of designated base station RTT, the base station RTT measured reporting period every other designated base station RTT, reports the measured base station RTT to the radio control station and, the radio control station, a report timer is started again expired and reporting cycle of activation has been the base station RTT elapses, reported the timer counts up by one of the timer start count every time expires And a stage for the reported base stations RTT measurements from the radio base station, the timer start number at the time of reporting, and stores denoted as base station RTT sequence number, the mobile station RTT reported from the mobile station The mobile station RTT sequence number that counts up one by one is added to the measurement result in the reported order and stored, and the difference between the base station RTT measurement result and the mobile station RTT measurement result with the corresponding sequence number The radio wave propagation time between the radio base station and the mobile station is calculated by using the difference, and the distance between the radio base station and the mobile station is calculated from the calculated radio wave propagation time .

  Thereby, the measurement time of the RTT measurement result combined in the difference calculation can be shortened, and a more accurate positioning calculation result can be obtained.

According to a second aspect of the present invention, there is provided a mobile communication system comprising at least one mobile station, at least one radio base station, and a radio control station that controls communication between the mobile station and the radio base station. The radio control station is a base station that is a value measured by the radio base station for a base station transmission / reception time difference that is a time from when the radio base station transmits a downlink signal to the mobile station and when it receives an uplink signal from the mobile station. Bureau RTT to report by measuring (Round Trip Time), with reporting period of report frequency and base station RTT base station RTT instructs the radio base station, the mobile station receives the downlink signal from the radio base station radio Measuring and reporting the mobile station RTT , which is a value measured at the mobile station, for the mobile station transmission / reception time difference until the uplink signal is transmitted to the base station, the number of reports of the mobile station RTT and the report cycle of the base station RTT Same move Instructs the mobile station together with the report cycle station RTT, the mobile station, when kicking receiving an indication of the mobile station RTT measurement reports from a radio control station, only report the number of mobile stations RTT instructed, designated mobile station RTT reporting measured mobile station RTT periodically every reported mobile station RTT measured in the radio control station, a radio base station, when kicking receiving an instruction of the base station RTT measurement reports from a radio control station, indicated The base station RTT is measured at the instructed base station RTT reporting frequency every reporting period of the base station RTT, the measured base station RTT is reported to the radio control station, and the radio control station is activated and the base station RTT is activated. and reporting timer reporting period is started again expired to lapse, reporting timer and means for counting up one by one the timer start count every time expires, the base station RT reported from the radio base station The measurement result, the timer start number at the time of reporting, and stores denoted as base station RTT sequence number to the mobile station RTT measurement result reported from the mobile station, the reported order counts up by 1 Mobile station RTT sequence number to be assigned and stored, a difference between the base station RTT measurement result and the mobile station RTT measurement result with the corresponding sequence number is obtained, and the difference between the radio base station and the mobile station is obtained by using the difference. A radio wave propagation time is calculated, and a distance between the radio base station and the mobile station is calculated from the calculated radio wave propagation time .

  Thereby, the measurement time of the RTT measurement result combined in the difference calculation can be shortened, and a more accurate positioning calculation result can be obtained.

  As described above, according to the present invention, it is possible to estimate the position and position of a mobile station more accurately.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 4, the radio control station 501 on the radio control system according to the present invention acquires the RTT measurement result according to the flowchart of FIG. The radio control station 501 first sets the timer half cycle of the first cycle as a backup cycle immediately before the RTT measurement start instruction in step 110 (step 100). Then, the radio control station 501 instructs the mobile station 502 and the radio base station 503A to start the RTT measurement by setting the RTT measurement result report cycle to the first cycle and the RTT measurement result report count to 5 times (step 110).

  Then, after the half-cycle timer, which is a preliminary cycle, has expired (step 120), the radio control station 501 further sets the timer of the first cycle to the RTT measurement result report setting count five times in the following steps 130 to 150. Set and receive RTT measurement results from the base station and mobile station respectively. When the RTT measurement result report is received five times, the wireless control device 501 ends the process (step 160).

  The base station RTT measurement result from the radio base station received during the first cycle timer operation according to the flowchart of FIG. 6 is stored in the radio control station 501 according to the flowchart of FIG. Further, the base station RTT measurement result from the mobile station received during the operation of the first period timer according to the flowchart of FIG. 6 is stored in the radio control station 501 according to the flowchart of FIG.

  FIG. 7 shows processing when the radio control station 501 receives a base station RTT measurement result from the radio base station between steps 130 and 140 in FIG. In step 200, the radio control station 501 sends an instruction to report five times in the first period. Thereafter, the radio control station 501 receives the base station RTT measurement result from the radio base station after the first period starts (step 210). The radio control station 501 checks whether the first period timer is in operation (step 220) and whether the number of measurements N has exceeded the set number of measurements (step 230). In 240, the base station RTT is stored in the base station RTT storage unit.

  When the base station RTT is stored in step 240, the radio control station 501 stores the base station RTT in association with the number of activations as the base station RTT of the base station A to B of the first period timer activation number N. Therefore, in FIG. 4, the base station RTT of the radio base station B that is received for the first time when the first period timer activation count N is 3 is stored in association with the information “activation count N = 3”.

  Incidentally, if data stored in the previous positioning process remains in the base station RTT storage unit, it is overwritten and stored with new data.

  On the other hand, with respect to the mobile station RTT, as shown in the flowchart of FIG. 8, the mobile station RTT storage unit of the radio control station is associated with the number of times the mobile station RTT has received each radio base station of the mobile station 503. To store. That is, the mobile RTT of a base station (base station B in FIG. 4) newly established by handover is distinguished from the mobile station RTT in transmission / reception with the base station A and is given the same reception number. (The mobile station RTT 3rd by transmission / reception with the base station A in FIG. 5 and the mobile station RTT 3rd transmission / reception by the base station B are simultaneously given), and are simultaneously reported to the radio control station.

  Incidentally, if data stored in the previous positioning process remains in the mobile station RTT storage unit, it is overwritten and stored with new data.

  The above steps of the radio control station 501, the radio base station 502, and the mobile station 503 will be described with reference to FIG. The radio control station 501 uses the RTT report cycle (first cycle) instructed to the radio base station and the mobile station immediately before the time when the radio base station and the mobile station are instructed to start RTT measurement (step 200, step 300). A timer with a short preliminary period is set (step 100). After the preliminary period timer expires (step 120), the radio control station 501 activates the first period timer which is the RTT reporting period time instructed to the radio base station and the mobile station (step 130), and activates the first period timer. Number is assigned in order from the first, and the base station RTT measurement result report (step 210) of the radio base station received within the N-th period of timer activation is associated with the number according to the flowchart of FIG. Remember. Further, the mobile station RTT measurement result reports (step 310) of the mobile station are numbered sequentially from the first according to the number of reports, and stored according to the flowchart of FIG. 8 as long as the number of reports M does not exceed the set number of measurements. To do.

  When the base station RTT and the mobile station RTT are acquired for each set number of times, the radio control station 501 calculates a difference by combining the stored RTT measurement results. More specifically, since the RTT measurement results of the base station and the mobile station correspond to the number of times the timer is started or the report reception order number as shown in FIG. 5, the base station corresponding to each number, the mobile station By calculating the difference between the station RTT measurement results, the radio wave propagation delay time can be derived.

  Here, the first base station RTT measurement result of the radio base station B is also associated with “N = 3”, which is the number of times the timer is started at the time of reception, and is therefore effective for the difference calculation for mobile station positioning. Can be used. At this time, since the base station RTT of the newly connected radio base station B after the handover is stored in association with the period of the first period timer managed by the radio control station 501, it corresponds to the same number of times. There is little difference in the measurement of the measurement results of the base station and the mobile station RTT, thereby improving the accuracy of position estimation of the mobile station.

  That is, in the present invention, the difference between the base station RTT measurement result report from the radio base station received by the radio control station and the mobile station RTT measurement result report from the mobile station is obtained in order to determine the position of the mobile station 501. At this time, the radio wave propagation time can be obtained more accurately by bringing the time when the RTT measurement is performed between the radio base station and the mobile station as close as possible. Thereby, the positioning accuracy of the mobile station can be improved.

  The present invention is effectively used for positioning in an IMT2000 mobile radio communication system or the like, but can also be used in other mobile radio communication systems.

  By using the radio control apparatus equipped with the present invention, it is possible to derive a more accurate radio wave propagation delay time, so that more accurate position estimation and position measurement of the mobile station can be expected.

It is a schematic diagram explaining the base station RTT and the mobile station RTT. FIG. 6 is a state diagram illustrating a reporting process of RTT measurement results. It is a conceptual diagram of the base station RTT and the mobile station RTT stored in the radio control station according to the prior art. FIG. 6 is a state diagram illustrating a reporting process of an RTT measurement result according to an embodiment of the present invention. It is a conceptual diagram of the base station RTT and the mobile station RTT stored in the radio control station according to one embodiment of the present invention. It is a control flowchart of the timer in the radio control station concerning one Embodiment of this invention. It is a control flowchart of base station RTT measurement result reception in the radio control station according to an embodiment of the present invention. It is a control flowchart of mobile station RTT measurement result reception in the radio control station according to an embodiment of the present invention.

Claims (2)

A radio control station that is included in a mobile communication system including at least one mobile station and at least one radio base station, and controls communication between the mobile station and the radio base station ,
The radio control station
A base station RTT (Round Trip) which is a value measured by the radio base station for a base station transmission / reception time difference, which is a time from when the radio base station transmits a downlink signal to the mobile station and when an uplink signal is received from the mobile station. to report to measure the Time), and instructs the radio base station along with reporting period of report frequency and base station RTT base station RTT, the base said mobile station receives the downlink signal from the radio base station The mobile station RTT report count and the base station RTT report cycle indicate that the mobile station RTT , which is a value measured by the mobile station, is a mobile station transmission / reception time difference until an uplink signal is transmitted to the station. With the same mobile station RTT reporting period as
Before Symbol mobile station,
Wherein when kicking receiving an indication of the mobile station RTT measurement reports from a radio control station, only report the number of the designated mobile station RTT, measured mobile station RTT reported period every of the designated mobile station RTT, measurement It reported the mobile station RTT was before Symbol radio control station,
The radio base station is
Wherein when kicking receiving an instruction of the base station RTT measurement reports from a radio control station, only report the number of the designated base station RTT, the base station RTT measured reporting period every of the designated base station RTT, measurement to report to the base station RTT before Symbol radio control station,
The radio control station
A report timer that is activated and expires when the reporting period of the base station RTT elapses, and means for incrementing the timer activation count by one each time the report timer expires,
The relative reported base station RTT measurements from the radio base station, the timer start number at the time of reporting, and stores denoted as base station RTT sequence number,
The mobile station RTT measurement result reported from the mobile station, the reported order to store assigned the mobile station RTT sequence number that increments by one,
Obtaining a difference between the base station RTT measurement result and the mobile station RTT measurement result with the corresponding sequence number;
A radio wave propagation time between the radio base station and the mobile station is calculated by using the difference, and a distance between the radio base station and the mobile station is calculated from the calculated radio wave propagation time. A radio control station of a mobile communication system. A mobile communication system comprising at least one mobile station, at least one radio base station, and a radio control station that controls communication between the mobile station and the radio base station,
The radio control station
A base station RTT (Round Trip) which is a value measured by the radio base station for a base station transmission / reception time difference, which is a time from when the radio base station transmits a downlink signal to the mobile station and when an uplink signal is received from the mobile station. to report to measure the Time), and instructs the radio base station along with reporting period of report frequency and base station RTT base station RTT, the base said mobile station receives the downlink signal from the radio base station The mobile station RTT report count and the base station RTT report cycle indicate that the mobile station RTT , which is a value measured by the mobile station, is a mobile station transmission / reception time difference until an uplink signal is transmitted to the station. With the same mobile station RTT reporting period as
Before Symbol mobile station,
Wherein when kicking receiving an indication of the mobile station RTT measurement reports from a radio control station, only report the number of the designated mobile station RTT, measured mobile station RTT reported period every of the designated mobile station RTT, measurement It reported the mobile station RTT was before Symbol radio control station,
The radio base station is
Wherein when kicking receiving an instruction of the base station RTT measurement reports from a radio control station, only report the number of the designated base station RTT, the base station RTT measured reporting period every of the designated base station RTT, measurement to report to the base station RTT before Symbol radio control station,
The radio control station
A report timer that is activated and expires when the reporting period of the base station RTT elapses, and means for incrementing the timer activation count by one each time the report timer expires,
The relative reported base station RTT measurements from the radio base station, the timer start number at the time of reporting, and stores denoted as base station RTT sequence number,
The mobile station RTT measurement result reported from the mobile station, the reported order to store assigned the mobile station RTT sequence number that increments by one,
Obtaining a difference between the base station RTT measurement result and the mobile station RTT measurement result with the corresponding sequence number;
A radio wave propagation time between the radio base station and the mobile station is calculated by using the difference, and a distance between the radio base station and the mobile station is calculated from the calculated radio wave propagation time. A mobile communication system.

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