JP2016184861A - Radio communication system, base station, management server, and terminal position estimation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system, a base station, and a terminal position estimation method that can accurately estimate the position of a radio terminal by eliminating the influence of a timing error between base stations while keeping down the consumption of resources for radio communication in the radio terminal.SOLUTION: A radio communication system according to the present invention includes a radio terminal, base stations, and a management server. Each of the plurality of base stations notifies the management server of deviation between frames of the base station and the other base stations, receives a connection request signal when the radio terminal transmits the connection request signal, and notifies the management server of the reception timing. The management server obtains the deviation among the frames and the reception timing reported by the plurality of base stations, calculates distance delay between the radio terminal and the plurality of base stations on the basis of the deviation of the frames and the reception timing, and thereby estimates the position of the radio terminal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a radio communication system including a radio terminal, a plurality of base stations that perform radio communication with the radio terminal, and a management server that manages the plurality of base stations, a base station included in the radio communication system, and a plurality of base stations The present invention also relates to a terminal position estimation method for estimating the position of a wireless terminal by a management server.

  In recent years, a GPS device mounted on a wireless terminal has been used as a method for acquiring position information of the wireless terminal. However, since the cost of the wireless terminal increases when the GPS device is mounted, it is not necessarily mounted on all wireless terminals. Therefore, the method using the GPS device has a problem that the position of the wireless terminal on which the GPS device is not mounted cannot be specified. In addition, when the GPS device is operated, the power consumption of the wireless terminal increases, and the user may invalidate the function.

  As a method of estimating the position of a wireless terminal when a GPS device is not installed or when the GPS device is not effective, a method of measuring three points using radio waves has been known before the GPS device has been developed. Yes. For example, Patent Document 1 discloses a method using transmission / reception of wireless signals between a wireless terminal and a plurality of base stations. In Patent Document 1, the distance between them is calculated based on the round-trip delay time between the mobile terminal (wireless device) and the base station. The distance between the mobile terminal and the adjacent base station is calculated based on the received power. Then, the position of the mobile terminal is estimated based on the calculated distance between the mobile terminal and the base station and the distance between the mobile terminal and the adjacent base station.

Japanese Patent No. 5595362

  However, in the method of Patent Document 1, in order to calculate the distance to the adjacent base station, the wireless terminal must perform wireless communication not only with the connected base station but also with the adjacent base station. For this reason, there is a possibility that resources for wireless communication in the wireless terminal will be significantly consumed. In addition, a frame shift (timing error) may occur between base stations and adjacent base stations. However, with the method of Patent Document 1, the influence of this timing error cannot be excluded, and the position estimation accuracy of the wireless terminal is reduced. I am worried about it.

  In view of such problems, the present invention can estimate the position of a wireless terminal with high accuracy by suppressing the consumption of wireless communication resources in the wireless terminal and excluding the influence of timing errors between base stations. An object of the present invention is to provide a possible radio communication system, base station, management server, and terminal location estimation method.

  In order to solve the above problems, a typical configuration of a wireless communication system according to the present invention includes a wireless terminal, a plurality of base stations that perform wireless communication with the wireless terminal, and a management server that manages the plurality of base stations. In the wireless communication system, the plurality of base stations notify the management server of a frame shift between the base station and another base station, and when the wireless terminal transmits a connection request signal, each base station Each station receives the connection request signal and notifies the management server of the reception timing. The management server obtains the frame shift and reception timing notified from the plurality of base stations, and the frame shift. The position of the wireless terminal is estimated by calculating a distance delay between the wireless terminal and a plurality of base stations based on the reception timing.

  In order to solve the above-described problem, the representative configuration of the management server according to the present invention is such that each base station transmits a connection request signal when a wireless terminal transmits a connection request signal and a frame shift notified from a plurality of base stations. Each of the connection request signals is received, and the position of the wireless terminal is estimated by calculating a distance delay between the wireless terminal and a plurality of base stations based on the reception timing.

  In order to solve the above-described problems, a representative configuration of a terminal location estimation method according to the present invention includes a plurality of base stations that perform wireless communication with a wireless terminal, and a wireless server by a management server that manages the plurality of base stations. A plurality of base stations notify the management server of a frame shift between the base station and another base station, and the wireless terminal transmits a connection request signal. Each base station receives the connection request signal and notifies the management server of the reception timing, and the management server acquires the frame shift and reception timing notified from the plurality of base stations. The position of the wireless terminal is estimated by calculating a distance delay between the wireless terminal and a plurality of base stations based on the frame shift and the reception timing. The features.

  In order to solve the above-described problem, a typical configuration of a base station according to the present invention is a base station that performs radio communication with a radio terminal, and detects a frame shift between the base station and another base station. When notifying a management server that manages a station and transmitting a connection request signal to a base station with a wireless terminal, each of the neighboring base stations that are not to be connected also receives the connection request signal and sends the reception timing to the management server. It is characterized by notifying.

  According to the present invention, it is possible to estimate the position of a radio terminal with high accuracy by suppressing the consumption of radio communication resources in the radio terminal and excluding the influence of timing errors between base stations. , A base station, a management server, and a terminal location estimation method can be provided.

It is a figure explaining the radio | wireless communications system concerning this embodiment. It is a sequence diagram explaining operation | movement in the radio | wireless communications system of this embodiment. It is a figure explaining monitoring of a control signal. It is a figure explaining the terminal position estimation method of this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a diagram illustrating a wireless communication system 100 according to the present embodiment. Hereinafter, in conjunction with the description of the wireless communication system 100 illustrated in FIG. 1, a base station included in the wireless communication system 100 and a terminal location estimation method in the wireless communication system 100 will be described in detail.

  As shown in FIG. 1, 100 of this embodiment includes a radio terminal 110, a plurality of base stations (base station A, base station B, base station C) that perform radio communication with the radio terminal 110, and a plurality of base stations. The management server 130 is configured to manage. In the present embodiment, the base station A is illustrated as a base station with which the radio terminal 110 transmits and receives radio signals, that is, a connection target, and the base stations B and C, which are other base stations, are illustrated as peripheral base stations. To do.

  In the present embodiment, three base stations are exemplified as the plurality of base stations, but the number of base stations is not limited to this. The number of base stations may be a base station to be connected and two or more neighboring base stations, that is, three or more, and the number of neighboring base stations can be changed as appropriate. In the following description, when the base stations A to C are not particularly distinguished, they are simply referred to as base stations.

  FIG. 2 is a sequence diagram for explaining the operation in the wireless communication system of the present embodiment. As shown in FIG. 2, in the wireless communication system 100 of this embodiment, a plurality of base stations monitor a control signal (hereinafter referred to as CCH) transmitted by a base station other than the own station, A frame shift from another base station is calculated (step S202, step S204, step S206).

  3A and 3B are diagrams for explaining control signal monitoring. FIG. 3A illustrates a normal communication frame, and FIG. 3B illustrates a CCH monitoring communication frame. As shown in FIGS. 3A and 3B, the communication frame of the base station includes four downlink slots (hereinafter referred to as DLs) for transmitting a radio signal to the radio terminal 110, and from the radio terminal 110. One frame is composed of four uplink slots (hereinafter referred to as UL) that receive radio signals.

  In the normal state, that is, when the CCH of another base station is not received as in the conventional case, the DL first slot is used for CCH transmission to the radio terminal 110 as shown in FIG. . The first slot of UL is used for CCH reception from the radio terminal 110.

  As shown in FIG. 3B, in the radio communication system 100 according to the present embodiment, the CCH to the radio terminal 110 is transmitted in the first slot of DL in the same way as in the normal time. On the other hand, in the UL, the first slot is used for CCH reception from the radio terminal 110, and the second slot to the fourth slot are used for CCH reception from other base stations as much as possible. Thereby, monitoring and reception of CCH of another base station are attained. The above “as much as possible” means that the slot is used when it is free. For example, if another wireless terminal is communicating in the base station B (TCH), priority is given to communication with the wireless terminal.

  FIG. 4 is a diagram for explaining a terminal position estimation method according to this embodiment. FIG. 4A is a diagram for explaining frame shift and reception timing, and FIG. 4B is a diagram for explaining calculation of the distance between the base station and the wireless terminal. In FIG. 4, the base station B is exemplified as the peripheral base station, but the present invention is not limited to this, and the base station C can also calculate the frame shift and the reception timing by the same method.

  For example, as shown on the left of the first row in FIG. 4A, the start time of the frame (and CCH) of the base station A is used as a reference. At this time, it is assumed that the frame shift between the base station A and the base station B is t1, as shown on the left of the fourth row in FIG. After calculating the frame shift with other base stations in this way, the base station notifies the management server 130 of the frame shift (step S212, step S214, step S216). Then, the management server 130 acquires the frame shift notified from the plurality of base stations.

  Next, the wireless terminal 110 transmits a connection request signal (hereinafter referred to as SCCH) for a certain base station (base station A in the present embodiment) (step S222). When the base station A receives the connection request signal, the base station A transmits an allocation signal to the wireless terminal 110 (step S228).

  Here, as described above, when the wireless terminal 110 transmits the SCCH to the connection target base station A, in the wireless communication system 100 according to the present embodiment, the base station B and the base station that are peripheral base stations that are not the connection target. The station C also receives the SCCH (steps S224 and S226). Base station A to base station C then calculate the reception timing at which the SCCH is received (steps S232, S234, and S236).

  For example, in the example shown on the right of the first stage in FIG. 4A, the timing when the base station A receives the SCCH is t2, and in the example shown on the right of the fourth stage in FIG. 4A, the base station B The timing of receiving the SCCH is t5.

  After calculating the timing of receiving the SCCH, the base station notifies the reception timing to the management server 130 (steps S242, S244, and S246). Then, the management server 130 acquires the reception timing notified from the plurality of base stations.

  As described above, when the frame shifts and the reception timings from the plurality of base stations are acquired, the management server 130 calculates the distance delay (the delay time depending on the distance) between the wireless terminal 110 and the plurality of base stations based on them. The position (terminal position) of the wireless terminal 110 is calculated and estimated (step S250).

  In the case of the base station A and the wireless terminal 110 that are the connection target base stations, as shown in the left of the second stage in FIG. 4A and (b), depending on the distance between the base station A and the wireless terminal 110 When the CCH transmitted from the base station A is received by the wireless terminal 110, a distance delay of t4 occurs.

  When the SCCH is transmitted from the wireless terminal 110 to the base station A, a distance delay of t4 is also generated (the same as the first stage right and the second stage left in FIG. 4A). (See right on the second row). Therefore, by dividing the reception timing t2 at the base station A (the time from the start of the frame at the base station A until the SCCH is received) by 2, the distance delay t4 between the base station A and the wireless terminal 110, and thus the base station The distance from A to the wireless terminal 110 can be estimated.

  Here, if there is no frame shift between the base station A and the base station B, the reception timing t3 when the base station B receives the SCCH as shown on the right of the third stage in FIG. This is the sum of the distance delay t4 between the base station A and the wireless terminal 110 and the distance delay t6 between the base station B and the wireless terminal 110. Therefore, if the distance delay t4 between the base station A and the wireless terminal 110 is calculated, the distance delay t6 between the base station B and the wireless terminal 110, and thus the distance between them is estimated.

  On the other hand, when there is a frame shift between the base station A and the base station B, the frame shift occurs as shown in the right of the fourth row in FIG. The distance delay t6 between the base station B and the radio terminal 110 cannot be obtained by simply subtracting the distance delay t4 between the base station A and the radio terminal 110 from the reception timing t5 when the station B receives the SCCH.

  Therefore, in the wireless communication system 100 and the terminal position estimation method of the present embodiment, first, the frame shift t1 between the base station A and the base station B is acquired as described above.

  Then, the sum of the frame shift t1 between the base station A and the base station B and the actual SCCH reception timing t5 of the base station B, the distance delay t4 between the base station A and the wireless terminal 110, and the base station B and the wireless terminal 110 The sum of the distance delays t6 is equal. From this, it is possible to estimate the distance delay t6 between the base station B and the wireless terminal 110, and hence the distance between them, by the expression “t6 = t1 + t5−t4”.

  Note that the time lengths of the frame, CCH, and SCCH shown in FIG. 4 are simply expressed and have no relation to the actual length.

  As described above, when the distance between each base station and the wireless terminal 110 is estimated, the management server 130 has circles 122a, 122b, and 122c whose radius is the distance from each base station to the wireless terminal 110 as shown in FIG. And the intersection of those circles is estimated as the position of the wireless terminal 110. When simulating a circle, it is preferable that the circle has a donut shape having a width. As a result, errors in the reception timing position and errors due to propagation path differences due to the multipath environment can be reduced.

  As described above, according to the wireless communication system 100 and the terminal position estimation method of the present embodiment, the distance delay between the wireless terminal 110 and the base station is calculated based on the frame shift between the base stations and the reception timing. As a result, the influence of the timing error between the base stations can be eliminated. Therefore, it is possible to estimate the position of the wireless terminal 110 with higher accuracy. In this embodiment, the wireless terminal 110 only needs to transmit and receive wireless signals to and from the connected base station, and it is not necessary to transmit or receive special wireless signals to other peripheral base stations. Therefore, the above-described effects can be obtained while suppressing the consumption of wireless communication resources in the wireless terminal 110. In addition, since the wireless terminal 110 only needs to perform communication similar to the conventional one, it is possible to estimate the position using the present invention for all existing wireless terminals.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention relates to a radio communication system including a radio terminal, a plurality of base stations that perform radio communication with the radio terminal, and a management server that manages the plurality of base stations, a base station included in the radio communication system, and a plurality of base stations It can also be used as a terminal position estimation method for estimating the position of a wireless terminal by the management server.

DESCRIPTION OF SYMBOLS 100 ... Wireless communication system, 110 ... Wireless terminal, 122a ... Circle, 122b ... Circle, 122c ... Circle, 130 ... Management server, A, B, C ... Base station

Claims (5)

A wireless communication system including a wireless terminal, a plurality of base stations that perform wireless communication with the wireless terminal, and a management server that manages the plurality of base stations,
The plurality of base stations are
Notifying the management server of the frame shift between the own station and another base station,
When the wireless terminal transmits a connection request signal, each base station receives the connection request signal and notifies the management server of the reception timing;
The management server
Obtain frame shift and reception timing notified from the plurality of base stations,
A wireless communication system, wherein a position of the wireless terminal is estimated by calculating a distance delay between the wireless terminal and a plurality of base stations based on the frame shift and the reception timing.   Based on the frame shift notified from a plurality of base stations and when each wireless terminal transmits a connection request signal, each base station receives the connection request signal and receives the connection request signal. A management server for estimating a position of the wireless terminal by calculating a distance delay with respect to the base station. A terminal position estimation method for estimating a position of a wireless terminal by a plurality of base stations that perform wireless communication with the wireless terminal, and a management server that manages the plurality of base stations,
The plurality of base stations are
Notifying the management server of the frame shift between the own station and another base station,
When the wireless terminal transmits a connection request signal, each base station receives the connection request signal and notifies the management server of the reception timing;
The management server
Obtain frame shift and reception timing notified from the plurality of base stations,
A terminal position estimation method for estimating a position of the wireless terminal by calculating a distance delay between the wireless terminal and a plurality of base stations based on the frame shift and the reception timing. A base station that performs wireless communication with a wireless terminal,
Notifying the management server that manages the base station of the frame shift between its own station and another base station,
When the wireless terminal transmits a connection request signal, the base station notifies the reception timing of the connection request signal to the management server. The base station according to claim 4, wherein the shift is calculated by receiving a control signal from another base station.

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