JP6608070B2 - Mobile station, base station, radio communication system and communication method - Google Patents

Description

  The present invention relates to a mobile station, a base station, a wireless communication system, and a communication method that perform wireless communication with a base station.

  Conventionally, when a base station covers a wide area in a communication system in which the base station and the mobile station perform radio communication, the mobile station has a problem that the received power level decreases as the distance from the base station decreases, and the radio quality decreases. is there. To solve this problem, it is possible to expand the coverage area, that is, the cell, in the base station while maintaining the radio quality in the mobile station by site diversity that transmits the same data from a plurality of adjacent base stations or antennas. Become. In an environment in which a mobile station moves at high speed, site diversity is an effective technique because it is necessary to expand cells in order to suppress instantaneous communication interruption of the mobile station due to handover.

  When a mobile body moves at a high speed, the mobile station requires a quick handover because the time that can exist in an overlap section of a cell composed of a plurality of base stations or antenna coverage areas is shortened. For this reason, in order to quickly detect a cell edge, the mobile station preferably knows which base station or antenna in the cell covers the area covered by the antenna. In Patent Document 1, in a multi-station simultaneous transmission system, each base station transmits a signal by offsetting the carrier frequency by a different value, and the wireless mobile station detects its own offset by detecting the offset of the received signal. A technique for detecting a zone or a coverage area of a base station is disclosed.

JP 2001-326959 A

  However, according to the above conventional technique, the radio mobile station needs to correct the reception frequency every time the frequency offset for each base station is identified. Therefore, when applied to a high-speed moving body such as a train radio system, there is a problem that a handover occurs before identifying a frequency offset of a certain base station, and the correction of the reception frequency may not be in time.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a mobile station that can detect the coverage area of an antenna in which the mobile station is present while reducing arithmetic processing.

  In order to solve the above-described problems and achieve the object, the present invention comprises a cell serving as a coverage area of a base station by a coverage area of one or a plurality of antennas, and the antenna is along a travel route of the mobile station. In a deployed wireless communication system, a mobile station that receives a signal from a base station. The mobile station is based on the number of antennas indicating the number of antennas constituting the cell in the base station included in the broadcast signal received from the base station, and the number of passes indicating the number of times the mobile station has detected the passage of the antenna in the cell. And a control unit for detecting the coverage area of the antenna in which the mobile station exists. In addition, the mobile station includes a storage unit that stores the number of antennas and the number of passages.

  The mobile station according to the present invention has an effect that the coverage area of the antenna in which the mobile station is present can be detected while reducing the arithmetic processing.

The figure which shows the structural example of the radio | wireless communications system concerning Embodiment 1. FIG. FIG. 2 is a block diagram showing a configuration example of a mobile station according to the first embodiment. FIG. 2 is a block diagram showing a configuration example of a base station according to the first embodiment. The flowchart which shows the process which transmits an alerting | reporting signal in the base station concerning Embodiment 1. FIG. The flowchart which shows the process which acquires the information of the number of antennas in the mobile station concerning Embodiment 1. The flowchart which shows the process which the mobile station concerning Embodiment 1 detects passage of an antenna in the cell of the connected base station. The figure which shows the example of the table which shows the relationship of the number of antennas and the frequency | count of passage when the memory | storage part of the mobile station concerning Embodiment 1 memorize | stores the frequency used by the connected base station is the frequency f1. The figure which shows the example of the table which shows the relationship between the number of antennas and the frequency | count of passage when the memory | storage part of the mobile station concerning Embodiment 1 memorize | stores the frequency used by the connected base station is the frequency f2. The flowchart which shows the process which detects the cover area of the antenna in which the own mobile station exists in the mobile station concerning Embodiment 1. FIG. The figure which shows the example in the case of comprising the processing circuit with which the mobile station concerning Embodiment 1 is provided using a processor and memory. The figure which shows the example in the case of comprising the processing circuit with which the mobile station concerning Embodiment 1 is provided with exclusive hardware. The figure which shows the structural example of the radio | wireless communications system concerning Embodiment 2. FIG. The figure which shows the directivity of the antenna of the radio | wireless communications system concerning Embodiment 2, and the intensity | strength of the received signal power level of the signal from each antenna in a mobile station The figure which shows transition of the intensity | strength of the received signal power level of the signal from the antenna accompanying the movement of a mobile station in the radio | wireless communications system concerning Embodiment 2. FIG. The flowchart which shows the process which the mobile station concerning Embodiment 2 detects passage of an antenna in the cell of the connected base station. The figure which shows the structural example of the radio | wireless communications system concerning Embodiment 3. FIG. The flowchart which shows the process which detects the change of a driving direction in the mobile station concerning Embodiment 3. FIG.

  Hereinafter, a mobile station, a base station, a wireless communication system, and a communication method according to embodiments of the present invention will be described in detail based on the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a wireless communication system 300 according to the first embodiment of the present invention. The radio communication system 300 includes base stations 100 and 110, antennas 101 and 102 connected to the base station 100, antennas 111 and 112 connected to the base station 110, and mobile stations 210, 220, and 230. In this embodiment, as an example, radio communication system 300 is a train radio system, and mobile stations 210 to 230 are trains. The mobile stations 210 to 230 actually communicate with the base stations 100 and 110 using a communication device mounted on the train. It is assumed that the antennas 101, 102, 111, and 112 are arranged along rails that are travel routes of the mobile stations 210 to 230 that are trains.

  The base station 100 sets a cell 103 constituted by the cover areas of the two antennas 101 and 102 as the cover area. Base station 100 transmits signals of the same content from antennas 101 and 102 at the same frequency. Base station 100 transmits signals from antennas 101 and 102 at frequency f1. In Embodiment 1, antennas 101 and 102 are omnidirectional antennas.

  The base station 110 sets a cell 113 configured by the cover areas of the two antennas 111 and 112 as a cover area. Base station 110 transmits signals of the same content from antennas 111 and 112 at the same frequency. Base station 110 transmits signals from antennas 111 and 112 at frequency f2. In Embodiment 1, the antennas 111 and 112 are omnidirectional antennas.

  The radio communication system 300 includes two base stations 100 and 110 in the example of FIG. 1, but may include three or more base stations. For example, in the wireless communication system 300, when the base stations 120 and 130 are installed on the right side of the base station 110, the base station 120 on the right side of the base station 110 transmits a signal at the frequency f1, and the right side of the base station 120 The adjacent base station 130 transmits a signal at the frequency f2, and a plurality of base stations alternately transmit signals at different frequencies. Note that, in the wireless communication system 300, a plurality of base stations are not limited to using two frequencies repeatedly and alternately, but only one frequency may be used, or three or more frequencies may be repeated. May be used.

  In FIG. 1, mobile stations 210 and 220 travel with the left direction in FIG. 1 as the forward direction, and mobile station 230 travels with the right direction in FIG. 1 as the forward direction. Note that the mobile station 230 exists at the end of the cell 103 and is traveling in the direction of handover from the cell 103 to the cell 113. Hereinafter, the mobile stations 210 to 230 are collectively referred to as a mobile station group 200.

  The configuration of the mobile stations 210 to 230 will be described. FIG. 2 is a block diagram of a configuration example of the mobile station 210 according to the first embodiment. Since the mobile stations 210 to 230 have the same configuration, the configuration will be described using the mobile station 210 as an example. The mobile station 210 includes an RF (Radio Frequency) unit 201, a baseband unit 202, a mobility management unit 203, a main processing unit 204, a power source 206, a storage unit 207, and an antenna 208. The movement management unit 203 and the main processing unit 204 constitute a control unit 205.

  The RF unit 201 modulates the baseband signal from the baseband unit 202 and demodulates the signal received by the antenna 208 into the baseband signal. The RF unit 201 is realized by, for example, a general-purpose IC (Integrated Circuit).

  The baseband unit 202 performs OSI (Modulation and A / D (Analog / Digital) conversion of a signal to be transmitted and D / A (Digital / Analog) conversion and demodulation of the baseband signal demodulated by the RF unit 201). The processing corresponding to layers 2 and 3 of the Open SYSTEM Interconnection) reference model is performed. The baseband unit 202 is realized by a general-purpose IC, for example.

  The mobility management unit 203 is a functional unit that manages the movement of the own mobile station, and manages, for example, a base station or an antenna coverage area where the own mobile station exists.

  The main processing unit 204 is a functional unit that performs application processing excluding mobility management of the own mobile station, and performs detection of antenna passage, which will be described later, which is characteristic processing in the present embodiment.

  The power source 206 supplies power to each unit of the mobile station 210.

  The storage unit 207 transmits the same signal acquired from the base station connected to the mobile station under the control of the main processing unit 204, and indicates the number of antennas Cant indicating the number of antennas constituting the cell, and the mobile station Stores the number of passes Cpass indicating the number of antennas that have passed through the cell.

  Antenna 208 transmits and receives signals to and from base stations 100 and 110. In FIG. 2, the mobile station 210 includes only one antenna 208. However, for example, all the frequencies may be transmitted / received by one antenna 208, or the antenna 208 that transmits / receives only one frequency is provided. A plurality may be provided.

  In mobile station 210, control unit 205 detects the coverage area of the antenna in which the mobile station is present based on the number of antennas Cant and the number of passages Cpass included in the broadcast signal received from base stations 100 and 110.

  The configuration of base stations 100 and 110 will be described. FIG. 3 is a block diagram of a configuration example of the base station 100 according to the first embodiment. Since the base stations 100 and 110 have the same configuration, the configuration will be described using the base station 100 as an example. The base station 100 includes an IDU (In Door Unit) 104, a mobile station management unit 105, a power source 106, and a storage unit 107.

  The IDU 104 converts a radio signal to be transmitted to a mobile station connected to the base station into an optical signal, and outputs the optical signal to the antennas 101 and 102 via an optical cable 108 and an ODU (Out Door Unit) 109.

  The mobile station management unit 105 manages mobile stations connected to its own base station, and performs destination determination when transmitting data.

  The power source 106 supplies power to each unit of the base station 100.

  The storage unit 107 stores information on the number of antennas Cant indicating information on the number of antennas 101 and 102 constituting the cell 103 of the base station. Specifically, the storage unit 107 stores “2” as the number of antennas Cant. In the example of the wireless communication system 300 illustrated in FIG. 1, the number of antennas Cant stored in the storage unit 107 of the base station 110 is also “2”.

  The optical cable 108 is a communication line that connects the IDU 104 and the ODU 109. The ODU 109 converts the optical signal received from the IDU 104 via the optical cable 108 into a radio signal, and transfers it to the antenna 101 and the antenna 102, respectively. In FIG. 1, the ODU 109 is actually arranged between the base station 100 and the antennas 101 and 102, and between the base station 110 and the antennas 111 and 112, but the description of the ODU 109 is omitted. In FIG. 3, the optical cable 108 and the ODU 109 are configured outside the base station 100, but the optical cable 108 and the ODU 109 may be handled as the base station 100.

  The base station 100 transmits to the mobile station connected to the base station, a broadcast signal broadcast at the frequency f1 via the antennas 101 and 102, including the number of antennas Cant. Similarly, the base station 110 transmits to the mobile station connected to the base station, a broadcast signal broadcast at the frequency f2 via the antennas 111 and 112, including the number of antennas Cant.

  Next, a description will be given of processing for detecting the passage of the antenna in the cell of the connected base station in the mobile stations 210 to 230. First, processing until the mobile stations 210 to 230 acquire information on the number of antennas Cant will be described.

  In the base station 100, the mobile station management unit 105 acquires the number of antennas Cant from the storage unit 107. The mobile station management unit 105 transmits a broadcast signal including the number of antennas Cant from the antennas 101 and 102 to the mobile station connected to the base station in the cell 103 via the IDU 104, the optical cable 108, and the ODU 109. To do. In the base station 110, the mobile station management unit 105 acquires the number of antennas Cant from the storage unit 107. The mobile station management unit 105 transmits a broadcast signal including the number of antennas Cant from the antennas 111 and 112 to the mobile station connected to the base station in the cell 113 via the IDU 104, the optical cable 108, and the ODU 109. To do.

  The mobile stations 210 to 230 receive the broadcast signal by establishing a connection with the base station of the cell in which the mobile station exists, and perform the reception process of the broadcast signal received by the baseband unit 202 to convert the broadcast signal into the broadcast signal. The number of antennas Cant included is acquired. Thereby, the mobile stations 210 to 230 acquire the number of antennas Cant indicating the number of antennas connected to the base station to which the mobile station itself is connected, that is, the number of antennas of the cell in which the mobile station is present. In the mobile stations 210 to 230, the main processing unit 204 causes the storage unit 207 to store the acquired number of antennas Cant.

  Specifically, the base stations 100 and 110 transmit a broadcast signal including information on the number of antennas Cant, for example, using a bit string stored in an area determined in the frame format of the broadcast signal. The mobile stations 210 to 230 acquire the number of antennas Cant by analyzing the information of the bit string stored in the area determined in the frame format of the broadcast signal. The mobile stations 210 to 230 store the number of antennas Cant without updating until the connected base station changes, that is, until transmission / reception at a different frequency is started by handover.

  In addition, when receiving signals from the base stations 100 and 110, the mobile stations 210 to 230 receive signals transmitted from antennas connected to the base stations 100 and 110 in detail. Specifically, the mobile stations 210 to 230 receive signals transmitted from the antennas 101 and 102 as signals from the base station 100. Similarly, the mobile stations 210 to 230 receive the signals transmitted from the antennas 111 and 112 as the signals from the base station 110. In the following description, when the mobile stations 210 to 230 receive signals, it is described as receiving signals from the base stations 100 and 110 for convenience, and may not be described as receiving signals transmitted from antennas. .

  FIG. 4 is a flowchart of a process of transmitting a notification signal in the base station 100 according to the first embodiment. Since the operations of the base stations 100 and 110 are the same, the base station 100 will be described as an example. In the base station 100, the mobile station management unit 105 reads the number of antennas Cant from the storage unit 107 (step S1). The mobile station management unit 105 generates a notification signal including the number of antennas Cant (step S2), and transmits the notification signal from the antennas 101 and 102 via the IDU 104, the optical cable 108, and the ODU 109 (step S3).

  FIG. 5 is a flowchart of a process of acquiring information on the number of antennas Cant in the mobile station 210 according to the first embodiment. Since the operations of the mobile stations 210 to 230 are the same, the mobile station 210 will be described as an example. In the mobile station 210, the main processing unit 204 receives the notification signal from the base station 100 via the antenna 208, the RF unit 201, and the baseband unit 202 (step S11). The main processing unit 204 extracts information on the number of antennas Cant from the notification signal (step S12), and stores the number of antennas Cant in the storage unit 207 (step S13). The main processing unit 204 extracts the number of antennas from the broadcast signal received from the handover destination base station each time the mobile station performs handover, and updates the number of antennas Cant stored in the storage unit 207.

  Next, processing in which the mobile stations 210 to 230 detect the passage of the antenna in the cell of the connected base station will be described.

  The mobile stations 210 to 230 store, in the storage unit 207, information on the number of times the antenna passes Cpass in the cell in which the mobile station exists. The initial value of the number of passes Cpass is “0”. The mobile stations 210 to 230 set the number of passages Cpass to the initial value “0” upon completion of the handover, and increment the number of passages Cpass by 1 each time the antenna passes through the handover destination cell.

  As a feature of mobile stations 210 to 230 in the present embodiment, mobile stations 210 to 230 detect a change in frequency of signals from base stations 100 and 110 received by antenna 208 using Doppler shift. Thus, the passage of the antenna in the cell is detected, and the number of passes Cpass is counted up by one. In the mobile stations 210 to 230, the Doppler shift is the frequency of the signal transmitted from the transmission source, which is the frequency of the signal received when approaching the transmission source, in the example of FIG. 1, the antennas 101, 102, 111, and 112. This is a phenomenon in which the reception frequency of the signal received when the frequency is higher than the transmission frequency is lower than the transmission frequency. The mobile stations 210 to 230 detect the passage of the antenna serving as the transmission source by detecting the point where the magnitude relationship between the reception frequency and the transmission frequency is reversed using the phenomenon of Doppler shift.

  Specifically, in the mobile stations 210 to 230, a signal from the base station received by the antenna 208, specifically, a signal from an antenna connected to the base station is sent to the main processing unit 204 via the RF unit 201 and the baseband unit 202. Sent. In the mobile stations 210 to 230, the main processing unit 204 acquires information on the reception frequency of the received signal from the baseband unit 202 every time, and observes and updates the effective values of the maximum frequency and the minimum frequency of the reception frequency, respectively. To do. The main processing unit 204 performs the observation of the highest frequency and the lowest frequency for a certain time, for example, until the own mobile station passes through ten antennas. The main processing unit 204 calculates an intermediate frequency from the highest frequency and the lowest frequency held last after the end of observation, and sets the calculated intermediate frequency as a transmission frequency. The main processing unit 204 detects that the reception frequency of the signal received from the base station, specifically the antenna connected to the base station, has changed from a frequency higher than the transmission frequency to a lower frequency with reference to the transmission frequency. Then, the passage of the antenna is detected.

  FIG. 6 is a flowchart illustrating processing in which the mobile stations 210 to 230 according to the first embodiment detect passage of an antenna in a cell of a connected base station. In the mobile stations 210 to 230, the main processing unit 204 receives a signal from the base station via the antenna 208, the RF unit 201, and the baseband unit 202 (step S21).

  The main processing unit 204 calculates and stores the difference between the reception frequency and the transmission frequency (step S22). In calculating the difference between the reception frequency and the transmission frequency, the main processing unit 204 may subtract the transmission frequency from the reception frequency, or may subtract the reception frequency from the transmission frequency. The main processing unit 204 may store a difference value, which is a calculated difference value, in the storage unit 207 or may be stored in a memory in the main processing unit 204 (not shown). The main processing unit 204 calculates the difference between the reception frequency and the transmission frequency every time a signal is received from the base station.

  The main processing unit 204 compares the code of the calculated difference value with the code of the previously calculated difference value stored in the internal or storage unit 207, and the code of the difference value calculated this time is the code of the difference value calculated previously. It is determined whether or not (step S23). Specifically, the main processing unit 204, when the sign of the difference value calculated last time is positive and the sign of the difference value calculated this time is positive, or when the sign of the difference value calculated last time is negative and the difference value calculated this time If the sign is negative, it is determined that the sign is the same. On the other hand, when the sign of the difference value calculated last time is positive and the sign of the difference value calculated this time is negative, or the sign of the difference value calculated this time is negative and the sign of the difference value calculated last time is negative. If it is positive, it is determined that the signs are different.

  If the compared two difference values have different signs (step S23: No), the main processing unit 204 counts the number of passages Cpass by one, assuming that the passage of the antenna is detected in the cell of the connected base station. Up (step S24). The main processing unit 204 stores the updated passage number Cpass in the storage unit 207 and updates the information on the passage number Cpass in the storage unit 207 (step S25). On the other hand, when the signs of the two difference values compared are the same (step S23: Yes), the main processing unit 204 assumes that the passage of the antenna is not detected in the cell of the connected base station, and the steps S24 and S25. The process ends without performing the process.

  Thus, the main processing unit 204 detects the passage of the antenna based on the difference between the reception frequency that is the frequency of the received signal and the transmission frequency that is the frequency of the signal when transmitted from the antenna. Through the above processing, the mobile stations 210 to 230 detect the passage of the antenna in the cell of the connected base station based on the change in frequency due to the Doppler shift, and count up the number of passages Cpass. It is possible to grasp the number of times the antenna passes in the cell. In this embodiment, the timing at which mobile stations 210 to 230 determine that the antenna has passed is the same as the timing when mobile stations 210 to 230 pass through the points where each antenna is installed in radio communication system 300 shown in FIG. Not when. The timing at which the mobile stations 210 to 230 determine that the antenna has passed through the mobile stations 210 to 230 is that the reception frequency of the signal from the antenna becomes smaller than the transmission frequency after passing through the point where each antenna is installed. It's time.

  Next, a method for managing the coverage area of the antenna in which the mobile station 210-230 is located in the cell of the base station to which the mobile station is connected will be described.

  FIG. 7 shows the relationship between the number of antennas Cant and the number of passages Cpass when the frequency used by the connected base station is stored in the storage unit 207 of the mobile stations 210 to 230 according to the first embodiment. It is a figure which shows the example of the table 500 which shows. FIG. 8 illustrates the number of antennas Cant and the number of passages Cpass when the frequency used by the connected base station is stored in the storage unit 207 of the mobile stations 210 to 230 according to the first embodiment. It is a figure which shows the example of the table 501 which shows these relationships. The mobility management unit 203 manages the frequency of the coverage area of the antenna where the mobile station exists based on the tables 500 and 501 which are databases stored in the storage unit 207. The tables 500 and 501 used when the mobile stations 210 to 230 manage the frequency of the cover area are examples, and are not limited to the contents shown in FIGS.

  Tables 500 and 501 shown in FIG. 7 and FIG. 8 show frequencies corresponding to the number of antennas Cant and the number of passes Cpass. The mobile stations 210 to 230 refer to the table 500 in FIG. 7 when the frequency used in the existing cell is the frequency f1, and use the table 501 in FIG. 8 when the frequency used in the existing cell is the frequency f2. refer.

  Specifically, in the mobile station 210 of the wireless communication system 300 shown in FIG. 1, a method will be described in which the mobility management unit 203 uses the table 500 shown in FIG. 7 to detect the antenna coverage area where the mobile station exists. .

  As shown in FIG. 1, the mobile station 210 exists in the cell 103 of the base station 100, passes through the antenna 102, and exists in the coverage area of the antenna 101. The frequency used by the base station 100 is the frequency f1. The movement management unit 203 refers to the number of antennas Cant and the number of passes Cpass stored in the storage unit 207. Since the number of antennas Cant in the cell 103 is “2”, the mobility management unit 203 refers to the row in which the number of antennas Cant is “2” in the table 500. In addition, since the mobility management unit 203 passes through the antenna in the cell 103 once, specifically, through the antenna 102, the table 500 refers to the column in which the number of passes Cpass is “1”.

  In the mobile station 210, the mobility management unit 203 refers to the second row and the second column of the table 500, and understands that the current use frequency is the frequency f1. Also, the movement management unit 203 refers to the second row and the third column of the table 500 when the number of times of passage Cpass increases by one when it passes through the antenna, more specifically, the antenna 101 once again, to “2”. As a result, the mobility management unit 203 can detect that the mobile station exists in the coverage area of the last antenna in the cell 103 because the use frequency changes to the frequency f2.

  That is, the mobility management unit 203 can recognize that the cell 103 exists in the cover area of the last antenna 101 that transmits a signal at the currently received frequency f1. As a simpler example, since the number of antennas Cant is “2” and the number of passages Cpass is “1”, the mobility management unit 203 passes the first of the two antennas constituting the cell 103. It can be seen that it can be detected that it is present in the cover area of the second antenna.

  Since it can be seen that the mobility management unit 203 of the mobile station 210 exists in the cell of the frequency f1, for example, at the time of handover or reconnection after link disconnection, without receiving a broadcast signal from the base station, By referring to the table 500, the frequency selection can be performed immediately. That is, the mobility management unit 203 of the mobile station 210 can easily determine that the frequency f1 should be selected.

  Next, in mobile station 220, a method will be described in which mobility management section 203 uses the table 501 shown in FIG. 8 to detect the coverage area of the antenna in which the mobile station exists.

  As shown in FIG. 1, the mobile station 220 exists in the cell 113 of the base station 110 and exists in the coverage area of the antenna 112. The frequency used by the base station 110 is the frequency f2. The movement management unit 203 refers to the number of antennas Cant and the number of passes Cpass stored in the storage unit 207. The mobility management unit 203 refers to the row in which the number of antennas Cant is “2” in the table 501 because the number of antennas Cant is “2” in the cell 113. In addition, since the mobility management unit 203 has never passed through the antenna in the cell 113, the mobility management unit 203 refers to a column in the table 501 where the number of passes Cpass is “0”.

  In the mobile station 220, the mobility management unit 203 refers to the second row and the first column of the table 501 and finds that the current use frequency is the frequency f2. Further, when passing through the antenna 112, the movement management unit 203 increases the number of passes Cpass by one to “1”, and refers to the second row and second column of the table 501. As a result, since the use frequency does not change, the mobility management unit 203 can detect that its own mobile station exists in the coverage area of the first antenna in the cell 103. In addition, the mobility management unit 203 can detect that the current mobile station exists in the coverage area of the antenna other than the last antenna in the current cell.

  That is, the mobility management unit 203 can recognize that the cell 113 is present in the coverage area of the first antenna 112 that transmits a signal at the currently received frequency f2. As a simpler example, since the number of antennas Cant is “2” and the number of passages Cpass is “0”, the mobility management unit 203 may not pass any one of the two antennas constituting the cell 113. Obviously, it can be detected that the first antenna is present in the cover area.

  Since the mobility management unit 203 of the mobile station 220 knows that it exists in the cell of the frequency f2, the table 501 is stored without receiving a broadcast signal from the base station, for example, at the time of reconnection after link disconnection. By referring to the frequency, it is possible to execute frequency selection immediately. That is, the mobility management unit 203 of the mobile station 220 can determine by simple processing that the frequency f2 should be selected.

  Next, in mobile station 230, a method in which mobility management section 203 detects the coverage area of the antenna where the mobile station exists using table 500 shown in FIG.

  As shown in FIG. 1, the mobile station 230 exists at the end of the cell 103 of the base station 100 and exists within the coverage area of the antenna 102. The frequency used by the base station 100 is the frequency f1. The movement management unit 203 refers to the number of antennas Cant and the number of passes Cpass stored in the storage unit 207. Since the number of antennas Cant in the cell 103 is “2”, the mobility management unit 203 refers to the row in which the number of antennas Cant is “2” in the table 500. In addition, since the mobility management unit 203 passes through the antenna in the cell 103 once, specifically, through the antenna 101, the table 500 refers to the column in which the number of passes Cpass is “1”.

  In the mobile station 230, the mobility management unit 203 refers to the second row and the second column of the table 500, and understands that the current use frequency is the frequency f1. Further, when the movement management unit 203 passes through the antenna once more, specifically, the antenna 102 again, the number of passes Cpass increases by one to “2” and refers to the second row and third column of the table 500. As a result, the mobility management unit 203 can detect that the mobile station exists in the coverage area of the last antenna in the cell 103 because the use frequency changes to the frequency f2.

  Here, in the mobile station 230, the mobility management unit 203 gradually increases the received signal strength from the base station 110, but referring to the second row and third column of the table 500, the cell 113 of the frequency f2 next. It can be seen that it is only necessary to invade. For this reason, the mobility management unit 203 detects that the mobile station is present in the coverage area of the last antenna in the cell 103, and the received signal strength from the base station 110, for example, exceeds the prescribed strength. A handover is performed at the determined timing to enter the cell 113.

  Thereafter, the mobile station 230 starts communication at the frequency f2 by receiving the broadcast signal transmitted from the antenna 111 constituting the cell 113, and changes the table to be referenced from the table 500 to the table 501. When the mobile station 230 receives the broadcast signal from the base station 110 from the antenna 111, it has not yet passed through the antenna 111, so the mobility management unit 203 starts reference from the second row and first column of the table 501.

  Thus, since the mobility management unit 203 of the mobile station 230 can grasp the frequency f1 of the existing cell 103 by using the table 500, reconnection occurs when the own mobile station exists at the cell boundary. Even in this case, it is possible to select the frequency of the cell to be connected without performing processing such as cell search. Further, since the mobile station 230 does not compare the received signal power level such as the broadcast signal, a cell having a high received signal power level that does not need to be connected is not erroneously selected.

  FIG. 9 is a flowchart of a process of detecting the antenna coverage area in which the mobile station exists in the mobile stations 210 to 230 according to the first embodiment. In the mobile stations 210 to 230, the mobility management unit 203 refers to the number of antennas Cant stored in the storage unit 207 (step S31), and refers to the number of passes Cpass stored in the storage unit 207 (step S32). . Based on the number of antennas Cant and the number of passages Cpass, the movement management unit 203 refers to the corresponding part of the table indicating the relationship between the number of antennas Cant and the number of passages Cpass (step S33). Specifically, the mobility management unit 203, among the tables indicating the relationship between the number of antennas Cant and the number of passages Cpass stored in the storage unit 207, corresponds to the number of antennas Cant corresponding to the frequency table used in the current cell. And reference is made to the portion of the number of passes Cpass.

  The movement management unit 203 checks whether or not the frequency obtained by referring to the table when the number of passes Cpass is counted up by one is different from the current frequency obtained by referring to the table (step S34). . When it is different from the current frequency (step S34: Yes), the mobility management unit 203 detects that its own mobile station exists in the coverage area of the last antenna of the current cell (step S35). On the other hand, when it is the same as the current frequency (step S34: No), the mobility management unit 203 detects that its own mobile station exists in the coverage area of the antenna other than the last antenna of the current cell (step S36). ).

  In addition, although the radio | wireless communications system 300 was demonstrated as a train radio system and the mobile stations 210-230 were demonstrated as a train, it is an example and is not limited to this. For example, the mobile stations 210 to 230 may be automobiles, and the antennas 101, 102, 111, and 112 may be applied to a communication system in which the mobile stations 210 to 230 are arranged along a road on which the mobile stations 210 to 230 travel. Further, in the wireless communication system 300, the base stations 100 and 110 configure the cover area of the base station by the cover areas of the two antennas. However, this is only an example, and the base stations 100 and 110 are configured using one or three or more antennas. You may comprise the coverage area of a base station. The same applies to the following embodiments.

  Next, the hardware configuration of the mobile station 210 will be described. Since the mobile stations 210 to 230 have the same configuration, the mobile station 210 will be described as an example. In the mobile station 210, the RF unit 201 and the baseband unit 202 are realized by a dedicated IC or the like as described above. The power source 206 is realized by a battery or a power circuit that receives power supplied from an overhead line (not shown in FIG. 1), converts the power into power used in each component, and outputs the power. The storage unit 207 is realized by a memory. The antenna 208 is realized by an antenna element. The movement management unit 203 and the main processing unit 204, that is, the control unit 205 are realized by a processing circuit. That is, the mobile station 210 obtains the number of antennas Cant, detects the passage of the antenna from the signal received from the base station, counts the number of times of passage Cpass, and the mobile station 210 exists using the number of antennas Cant and the number of times of passage Cpass. And a processing circuit for detecting the antenna coverage area. The processing circuit may be dedicated hardware, or a processor and a memory that execute a program stored in the memory.

  FIG. 10 is a diagram illustrating an example in which the processing circuit 80 included in the mobile station 210 according to the first embodiment is configured using a CPU and a memory. The processing circuit 80 includes a processor 81 that executes a program stored in the memory 82, a memory 82 that stores information such as a program executed by the processor 81, an input interface 83 to which data and the like are input from other configurations, and others The output interface 84 for outputting data or the like to the configuration is provided, and each is connected by a system bus 85. When the processing circuit 80 is configured as shown in FIG. 10, each function of the processing circuit included in the mobile station 210 is realized by software, firmware, or a combination of software and firmware. Software or firmware is described as a program and stored in the memory 82. In the processing circuit 80, the processor 81 reads out and executes the program stored in the memory 82, thereby realizing each function. That is, when the mobile management unit 203 and the main processing unit 204 are executed by the processing circuit 80, the mobile station 210 detects the number of antennas Cant, detects the passage of the antenna from the signal received from the base station, and passes through. A memory 82 for storing a program in which the step of counting the number of times Cpass, the step of detecting the coverage area of the antenna in which the mobile station exists using the number of antennas Cant and the number of passages Cpass is executed. Prepare. These programs can also be said to cause a computer to execute the procedure and method of the mobile station 210.

  Here, the processor 81 may be a processing device, an arithmetic device, a microprocessor, a microcomputer, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or the like. The memory 82 is, for example, a nonvolatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (Electrically EPROM). A magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), or the like is applicable.

  FIG. 11 is a diagram illustrating an example in which the processing circuit 80 included in the mobile station 210 according to the first embodiment is configured with dedicated hardware. When the processing circuit 80 is dedicated hardware, the processing circuit 86 shown in FIG. 11 includes, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), and an FPGA. (Field Programmable Gate Array) or a combination of these. Each function of the mobile station 210 may be realized by the processing circuit 86 for each function, or each function may be realized by the processing circuit 86 collectively.

  Note that a part of each function of the mobile station 210 may be realized by dedicated hardware, and a part may be realized by software or firmware. As described above, the processing circuit can realize the above-described functions by dedicated hardware, software, firmware, or a combination thereof.

  In addition, although the structure of the mobile stations 210-230 was demonstrated, the structure of the base stations 100 and 110 is also the same. That is, of the base stations 100 and 110, the mobile station management unit 105 can be realized by a processing circuit as shown in FIGS.

  As described above, according to the present embodiment, in radio communication system 300, mobile stations 210 to 230 detect the passage of antennas constituting the cells of base stations 100 and 110 based on changes in the frequency of received signals. In addition, by managing the number of times the antenna passes, it is possible to easily detect the antenna coverage area of the own mobile station in the cell. Further, the mobile stations 210 to 230 can determine which cell should be connected, that is, which frequency should be connected with reference to a table internally managed. The mobile stations 210 to 230 do not require frequency offset detection as in the prior art, and do not require GPS (Global Positioning System) position information, etc., based on information broadcast from the base station or antenna, It is possible to detect the cover area. Thereby, the mobile stations 210 to 230 can detect the cover area where the mobile station is present by a simple process while reducing the arithmetic process as compared with the conventional one. Also, the mobile stations 210 to 230 can realize quick cell selection, that is, frequency selection that does not require processing such as measurement and comparison of the frequency of the received signal. This is an effective means that can shorten the time required to select an appropriate base station, particularly when quick reconnection is required in a system in which an emergency signal or the like is transmitted.

  In addition, since only the notification signal in the wireless communication system 300 is used, even when the system configuration such as the number of antennas Cant changes, only the number of antennas Cant stored on the base stations 100 and 110 side needs to be changed. . The case where the system configuration is changed is, for example, a case where an antenna is added. Since the mobile stations 210 to 230 need not be changed, the maintenance load can be reduced.

  Note that the radio communication system 300 is not limited to that shown in FIG. 1, and can be applied to, for example, a multi-station simultaneous transmission system in which a plurality of base stations constitute one large cell. Further, the frequency does not need to be a system that repeats two frequencies, and it does not depend on how many components shown in FIG. Furthermore, although the mobile stations 210 to 230 calculate the transmission frequency of the base station from the highest frequency and the lowest frequency of signals observed in the past, the method of grasping the transmission frequency is not limited to this. For example, in the mobile stations 210 to 230, the deviation from the transmission frequency can be reduced by a method such as using a highly accurate transmitter, so that it is possible to grasp the transmission frequency without observing the maximum frequency and the minimum frequency. is there. Further, although a train radio system has been described as an example of the radio communication system 300, it is obvious that the mobile stations 210 to 230 need not be trains. Further, it is obvious that the antenna passage detection method based on the frequency change shown in the first embodiment can be applied not only to the wireless communication system 300 illustrated in FIG. 1 of the first embodiment.

Embodiment 2. FIG.
In Embodiment 2, base stations 100 and 110 use directional antennas. A different part from Embodiment 1 is demonstrated.

  FIG. 12 is a diagram of a configuration example of the wireless communication system 300a according to the second embodiment. The wireless communication system 300a includes base stations 100 and 110, antennas 101a and 102a connected to the base station 100, antennas 111a and 112a connected to the base station 110, and mobile stations 210 to 230. In this embodiment, as an example, radio communication system 300a is a train radio system, and mobile stations 210 to 230 are trains. It is assumed that the antennas 101a, 102a, 111a, and 112a are arranged along rails that are travel routes of the mobile stations 210 to 230 that are trains.

  The base station 100 sets a cell 103a composed of the cover areas of the two antennas 101a and 102a as the cover area. The base station 100 transmits signals having the same content at the same frequency from the antennas 101a and 102a. Base station 100 transmits signals from antennas 101a and 102a at frequency f1. In Embodiment 2, the antennas 101a and 102a are directional antennas.

  The base station 110 sets a cell 113a configured by the cover areas of the two antennas 111a and 112a as a cover area. The base station 110 transmits signals having the same content at the same frequency from the antennas 111a and 112a. The base station 110 transmits signals from the antennas 111a and 112a at the frequency f2. In Embodiment 2, the antennas 111a and 112a are directional antennas.

  The configurations of mobile stations 210 to 230 and base stations 100 and 110 are the same as those in the first embodiment. However, the base station 100 is connected to the antennas 101a and 102a via the ODU 109 not shown in FIG. Further, the base station 110 is connected to the antennas 111a and 112a via the ODU 109 not shown in FIG. Base stations 100 and 110 are different from those in the first embodiment in the antennas to be connected.

  In the first embodiment, the mobile stations 210 to 230 detect the passage of the antenna based on the change in the reception frequency of the signals from the base stations 100 and 110. On the other hand, in Embodiment 2, the mobile stations 210 to 230 detect the passage of the antenna based on the fluctuation of the received signal power level of the signal received from the base station.

  FIG. 13 is a diagram illustrating the directivity of the antennas 101a, 102a, 111a, and 112a of the wireless communication system 300a according to the second embodiment and the intensity of the received signal power level of the signal from each antenna in the mobile stations 210 to 230. . The antennas 101a, 102a, 111a, and 112a are antennas having directivity on the right side in FIG. That is, the cover areas of the antennas 101a, 102a, 111a, and 112a are on the right side of the installation position of each antenna in FIG. In the mobile stations 210 to 230, on the right side of each antenna, the strength of the received signal power level increases as the distance from the antenna increases. On the other hand, the mobile stations 210 to 230 cannot receive a signal from the nearest antenna on the left side of each antenna even if they are close to each antenna, and receive a signal from a distant antenna on the left side of the mobile station. As a result, the intensity of the received signal power level is reduced.

  FIG. 14 is a diagram illustrating the transition of the strength of the received signal power level of the signals from the antennas 101a and 102a accompanying the movement of the mobile station 210 in the wireless communication system 300a according to the second embodiment. As shown in FIG. 14, the mobile station 210 is moving from the right side to the left side. In the mobile station 210, the distance to the antenna 102a becomes shorter with movement, that is, with the passage of time while the mobile station 210 exists in the cover area of the antenna 102a, so that the received signal power level gradually increases. When the mobile station 210 passes through the antenna 102a, the mobile station 210 moves out of the cover area of the antenna 102a and exists in the cover area of the adjacent antenna 101a. At this time, since the distance between the mobile station 210 and the antenna 101a is large, the received signal power level is greatly reduced in the mobile station 210. The mobile station 210 detects the passage of the antenna when the absolute value of the fluctuation of the received signal power level at this time exceeds a predetermined threshold value.

  Contrary to the above example, when the mobile station 210 moves from the left side to the right side in FIG. 14, the mobile station 210 moves, that is, with the passage of time while it is in the coverage area of the antenna 101a. Since the distance to the antenna 101a becomes longer, the received signal power level gradually decreases. When the mobile station 210 passes the antenna 102a, the mobile station 210 enters the cover area of the antenna 102a and exists in the cover area of the antenna 102a. At this time, since the distance between the mobile station 210 and the antenna 102a is short, the received signal power level rapidly increases in the mobile station 210. The mobile station 210 detects the passage of the antenna when the absolute value of the fluctuation of the received signal power level at this time exceeds a predetermined threshold value.

  Specifically, processing in which the mobile stations 210 to 230 detect the passage of the antenna in the cell of the base station to which the mobile stations 210 to 230 are connected will be described. In Embodiment 2, in mobile stations 210 to 230, a signal from a base station received by antenna 208 is transmitted to main processing section 204 via RF section 201 and baseband section 202. The main processing unit 204 acquires information on the received signal power level of the received signal from the baseband unit 202 each time, and stores information on the received signal power level. Further, the main processing unit 204 calculates and stores an average received signal power level that is an average value of the received signal power levels of the latest several times for the received signal power level of the received signal. The main processing unit 204 compares the average received signal power level stored internally or in the storage unit 207 with the latest received signal power level. The main processing unit 204 detects the fluctuation of the received signal power level when the absolute value of the difference between the average received signal power level and the latest received signal power level exceeds a predetermined threshold, thereby passing the antenna Is detected.

  FIG. 15 is a flowchart illustrating processing in which the mobile stations 210 to 230 according to the second embodiment detect the passage of an antenna in a cell of a connected base station. In the mobile stations 210 to 230, the main processing unit 204 receives a signal from the base station via the antenna 208, the RF unit 201, and the baseband unit 202 (step S41).

  The main processing unit 204 calculates and stores the difference between the latest received signal power level received this time and the calculated average received signal power level (step S42). The main processing unit 204 may subtract the average received signal power level from the latest received signal power level or calculate the average received signal power level in calculating the difference between the latest received signal power level and the average received signal power level. The latest received signal power level may be subtracted from the power level. The main processing unit 204 may store a difference value, which is a calculated difference value, in the storage unit 207 or may be stored in a memory in the main processing unit 204 (not shown). The main processing unit 204 calculates a difference between the latest received signal power level and the average received signal power level every time a signal is received from the base station.

  The main processing unit 204 determines whether or not the absolute value of the calculated difference value is equal to or greater than a predetermined threshold value (step S43). When the absolute value of the calculated difference value is equal to or greater than the threshold (step S43: Yes), the main processing unit 204 counts up the number of times of passage Cpass by assuming that the antenna has passed in the connected base station cell. (Step S44). The main processing unit 204 stores the updated passage number Cpass in the storage unit 207 and updates the information on the passage number Cpass in the storage unit 207 (step S45). Further, as shown in FIG. 14, the main processing unit 204 clears the average received signal power level that has been calculated and stored because the received signal power level differs greatly before and after the passage of the antenna is detected (step S120). S46). In this case, the main processing unit 204 may temporarily store the latest received signal power level this time as the average received signal power level for the next processing.

  On the other hand, when the absolute value of the calculated difference value is less than the threshold value (step S43: No), the main processing unit 204 assumes that the antenna has not been detected in the cell of the connected base station, The average received signal power level is calculated using the received signal power level, and the stored average received signal power level is updated (step S47).

  Thus, the main processing unit 204 detects the passage of the antenna based on the transition of the received signal power level of the received signal. Through the above processing, the mobile stations 210 to 230 detect the passage of the antenna in the cell of the connected base station based on the change in the received signal power level, and count up the number of passes Cpass. It is possible to grasp the number of times the antenna passes in the cell. Note that in this embodiment, the timing at which the mobile stations 210 to 230 determine that they have passed through the antenna is different from that in Embodiment 1, and in the wireless communication system 300a shown in FIG. It is when it passes through the installed point.

  In mobile stations 210 to 230, in the cell of the base station to which the mobile station is connected, the method for managing the coverage area of the antenna in which the mobile station exists is the same as in the first embodiment.

  As described above, according to the present embodiment, in radio communication system 300a, mobile stations 210 to 230 detect the passage of antennas constituting the cells of base stations 100 and 110 based on fluctuations in received signal power levels. In addition, by managing the number of times the antenna passes, it is possible to easily detect the antenna coverage area of the cell in which the mobile station is present. Thereby, the mobile stations 210 to 230 can obtain the same effects as those of the first embodiment.

  It is also possible to construct a radio communication system that simultaneously realizes the antenna passage detection method based on the variation of the received signal power level shown in the second embodiment and the antenna passage detection method based on the frequency change shown in the first embodiment. Is possible. In this case, in the mobile stations 210 to 230, the main processing unit 204 may detect the change of the reception frequency and detect the passage of the antenna only when the change of the reception signal power level is detected. The passing of the antenna may be detected when only one of the change of the frequency sign or the fluctuation of the received signal power level is detected. Further, the main processing unit 204 may adaptively switch between the two antenna passage determination criteria. Further, it is obvious that the antenna passing detection method based on the variation of the received signal power level shown in the second embodiment can be applied not only to the radio communication system 300a illustrated in FIG. 12 of the second embodiment.

Embodiment 3 FIG.
The radio communication system 300a according to the second embodiment detects the passage of the antenna when the mobile stations 210 to 230 travel in one direction. In the third embodiment, an antenna passage detection method when the mobile station 230 travels in the reverse direction from the middle in the cell 103a formed by the base station 100 will be described. In the third embodiment, specifically, the mobile station 230 resets the number of passes Cpass when the traveling direction is reversed, and realizes an appropriate count of the number of times the antenna passes even when traveling in the reverse direction.

  FIG. 16 is a diagram of a configuration example of a wireless communication system 300a according to the third embodiment. Although the configuration of the wireless communication system 300a is the same as that of the second embodiment, FIG. 16 is obtained by extracting the base station 100, the antennas 101a and 102a, and the mobile station 230 from FIG. FIG. 16 shows a state in which the mobile station 230 changes the traveling direction to the left direction 401 in the reverse direction after traveling in the right direction 400.

  The mobile station 230 exists in the coverage area of the antenna 102a in the cell 103a. The mobile station 230 detects the number of antennas Cant = 2 and the number of times of passage Cpass = 1 by the antenna passage detection method described in Embodiment 2, and is present in the coverage area of the last antenna 102a in the existing cell 103a. Is detected. In the table shown in FIG. 7, this corresponds to the portion of 2 rows and 2 columns. Since the mobile station 230 is away from the antenna 102a every moment, the received signal power level decreases as time elapses according to the transition of the received signal power level shown in FIG.

  Here, the mobile station 230 starts traveling in the reverse direction, that is, the left direction 401 after traveling in the right direction 400. In this case, since the mobile station 230 moves closer to the antenna 102a every moment, the received signal power level increases as time elapses according to the transition of the received signal power level shown in FIG. .

  At this time, when the main processing unit 204 of the mobile station 230 stores a plurality of values of the average received signal power level in the past, the transition of the average received signal power level has changed from falling to rising. It can be detected that the traveling direction of the station has changed to the opposite direction. For example, the main processing unit 204 calculates an average received signal power level that is an average value of the received signal power levels for a specified number of times, and based on the transition of the average received signal power level, the traveling direction of the mobile station is determined. Detects change in the reverse direction. The method for calculating the average received signal power level in main processing section 204 may be the same as in the second embodiment.

  When the main processing unit 204 detects that the traveling direction of the mobile station has changed in the reverse direction, the main processing unit 204 resets the information on the number of passes Cpass stored in the storage unit 207 according to the following equation (1): A new passage count Cpass is set and written in the storage unit 207 to be updated.

  Cpass = Cant−Cpass ′ (1)

  Here, the number of times of passage Cpass ′ is determined by the mobile station in the row indicating the number of corresponding antennas Cant in the table 500 shown in FIG. 7 or the table 501 shown in FIG. It shows the number of antennas in a cell in which the antenna constituting the existing cover area is transmitting the same frequency.

  For example, in the case of the wireless communication system 300a shown in FIG. 16, since the frequency of the cell 103a in which the mobile station 230 exists is the frequency f1, the mobility management unit 203 It can be seen that there are two antennas that transmit. In the movement management unit 203 of the mobile station 230 whose traveling direction is the right direction 400, the own mobile station exists in the cover area of the second antenna 102a, and thus the number of passes Cpass' = 2. Is different from the value of the number of passes Cpass = 1.

  Specifically, in the wireless communication system 300a shown in FIG. 16, information regarding antennas when the mobile station 230 is traveling in the right direction 400 is the number of antennas Cant = 2 and the number of passes Cpass = 1. However, when detecting that the mobile station 230 has changed the traveling direction and started traveling in the left direction 401, the mobility management unit 203 does not update the number of antennas Cant = 2 for the information related to the antennas, and the equation (1) To update the number of passages Cpass = 2-2 = 0. This means that the mobile station 230 has not passed through the antenna that constitutes the cell 103a because it has traveled in the left direction 401. When the traveling direction is the left direction 401, the antenna 102a is the first antenna constituting the cell 103a. As shown in FIG. 16, the mobile station 230 actually has never passed through the antenna constituting the cell 103a.

  FIG. 17 is a flowchart of a process of detecting a change in the traveling direction in the mobile station 230 according to the third embodiment. The mobility management unit 203 calculates the average received signal power level (step S51). The process of calculating the average received signal power level in the movement management unit 203 may be the same as the process of step S46 or step S47 in the flowchart of FIG. 15 of the second embodiment.

  The mobility management unit 203 compares the latest average received signal power level with the past average received signal power level (step S52). If the transition of the latest average received signal power level changes with respect to the past average received signal power level (step S53: Yes), the mobility management unit 203 determines that the traveling direction of the mobile station has changed in the reverse direction. Determination is made (step S54). In this case, the movement management unit 203 updates the number of passes Cpass according to the equation (1) as described above (step S55), stores the updated number of passes Cpass in the storage unit 207, and sets the number of passes Cpass in the storage unit 207. Information is updated (step S56).

  On the other hand, if the transition of the latest average received signal power level has not changed with respect to the past average received signal power level (step S53: No), the mobility management unit 203 has the same traveling direction of the mobile station. That is, it is determined that the direction has not changed in the reverse direction (step S57). The movement management unit 203 ends without performing the processing of step S55 and step S56.

  As described above, according to the present embodiment, in radio communication system 300a, mobile station 230 detects a trend change in the average received signal power level, so that the traveling direction of the mobile station is reverse. It is possible to easily detect that the change has occurred. Thereby, the mobile station 230 can appropriately update the number of passages Cpass. Although the mobile station 230 has been described, the mobile station 210 and 220 can perform the same operation.

  Needless to say, the wireless communication system 300a that simultaneously realizes the detection method of the change in the traveling direction of the mobile station shown in the third embodiment and the antenna passage detection method shown in the second embodiment can be constructed. It is obvious that the present invention is not limited to the wireless communication system 300a illustrated in FIG.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  100, 110 Base station, 101, 101a, 102, 102a, 111, 111a, 112, 112a, 208 Antenna, 103, 103a, 113, 113a Cell, 104 IDU, 105 Mobile station manager, 106, 206 Power supply, 107, 207 storage unit, 108 optical cable, 109 ODU, 210, 220, 230 mobile station, 201 RF unit, 202 baseband unit, 203 mobility management unit, 204 main processing unit, 205 control unit, 300, 300a wireless communication system.

Claims (16)

A cell serving as a coverage area of a base station is configured by a coverage area of one or a plurality of antennas, and a signal from the base station is received in a wireless communication system in which the antenna is disposed along a travel route of a mobile station The mobile station,
Based on the number of antennas indicating the number of antennas constituting the cell included in the broadcast signal received from the base station, and the number of times of passage indicating the number of times the own mobile station has detected passage of the antenna in the cell A control unit for detecting the coverage area of the antenna in which
A storage unit for storing the number of antennas and the number of passages;
A mobile station comprising: The control unit extracts the number of antennas from the notification signal, and stores the extracted number of antennas in the storage unit.
The mobile station according to claim 1. The control unit extracts the number of antennas from a broadcast signal received from a handover destination base station each time the mobile station performs handover, and updates the number of antennas stored in the storage unit.
The mobile station according to claim 2. The control unit detects passage of the antenna based on a difference between a reception frequency that is a frequency of a received signal and a transmission frequency that is a frequency of a signal transmitted by the antenna.
The mobile station according to any one of claims 1 to 3, characterized in that: The control unit detects passage of the antenna based on a transition of a received signal power level of a received signal.
The mobile station according to any one of claims 1 to 3, characterized in that: When the control unit detects that the traveling direction of the mobile station has changed in the reverse direction, the control unit updates the number of passes stored in the storage unit,
The mobile station according to claim 5. The control unit calculates an average received signal power level that is an average value of received signal power levels for a specified number of times, and based on the transition of the average received signal power level, the traveling direction of the mobile station is reverse To detect changes to
The mobile station according to claim 6. The wireless communication system according to any one of claims 1 to 7, wherein a cell serving as a coverage area of a base station is configured by a coverage area of one or a plurality of antennas, and the antenna is arranged along a travel route of a mobile station. The base station that communicates with the mobile station according to claim 1,
A storage unit for storing the number of antennas indicating the number of antennas constituting the cell;
A mobile station management unit that performs control to transmit a broadcast signal including information on the number of antennas to a mobile station existing in the cell;
A base station comprising: A mobile station according to any one of claims 1 to 7,
A base station according to claim 8;
A wireless communication system comprising: A cell serving as a coverage area of a base station is configured by a coverage area of one or a plurality of antennas, and the antenna is arranged along a travel route of a mobile station.
A broadcast signal transmission step in which a base station transmits a broadcast signal including information on the number of antennas indicating the number of antennas constituting the cell in the base station to a mobile station existing in the cell;
An antenna in which the mobile station exists based on the number of antennas included in the broadcast signal received from the base station by the mobile station and the number of times the mobile station has detected the passage of the antenna in the cell. A cover area detection step for detecting the cover area of
A communication method comprising: In the cover area detection step, the mobile station extracts the number of antennas from the broadcast signal and stores the extracted number of antennas.
The communication method according to claim 10. In the cover area detection step, the mobile station extracts the number of antennas from a broadcast signal received from a handover destination base station every time it performs a handover, and updates the number of antennas to be stored.
The communication method according to claim 11. In the cover area detection step, the mobile station detects passage of the antenna based on a difference between a reception frequency that is a frequency of a received signal and a transmission frequency that is a frequency of a signal transmitted by the antenna.
The communication method according to any one of claims 10 to 12, wherein: In the cover area detecting step, the mobile station detects passage of the antenna based on a transition of a received signal power level of a received signal.
The communication method according to any one of claims 10 to 12, wherein: In the cover area detection step, when the mobile station detects that the traveling direction has changed in the reverse direction, the mobile station updates the number of passes.
The communication method according to claim 14. In the cover area detecting step, the mobile station calculates an average received signal power level that is an average value of the received signal power levels for a specified number of times, and based on the transition of the average received signal power level, the traveling direction Detect that has changed in the opposite direction,
The communication method according to claim 15.

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