JP6240655B2 - Wireless base station, wireless terminal and processor - Google Patents

Description

  The present invention relates to a radio base station, a radio terminal, and a processor.

  In recent years, services using location information indicating the geographical location of a wireless terminal (hereinafter abbreviated as “location information of a wireless terminal” as appropriate) have been provided.

  With the spread of such services, the 3GPP (3rd Generation Partnership Project), which is a standardization organization for wireless communication systems, is proceeding with standardization of positioning technology for acquiring location information of wireless terminals (Non-Patent Document 1). reference).

  The positioning technology includes a type in which a wireless terminal obtains location information by itself and a type in which location information is obtained by a location information server provided on the network side. The location information server may be referred to as an E-SMLC (Evolved Serving Mobile Location Center).

3GPP TS 36.305: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Stage 2 functional specification of User Equipment (UE) positioning in E-UTRAN”

  By the way, it is considered that advanced communication control can be realized by making the position information of the wireless terminal available to the wireless base station.

  However, when the radio base station acquires the location information of the radio terminal from the location information server, there is a problem that signaling occurs between the radio base station and the location information server, increasing network traffic.

  Accordingly, an object of the present invention is to provide a radio base station and a control method therefor that can suppress an increase in network traffic even when performing processing that needs to acquire location information of a radio terminal.

  In order to solve the above-described problems, the present invention has the following features. First, a feature of the radio base station according to the present invention is that a transmission unit that transmits a capability information transmission request for requesting transmission of terminal capability information indicating the positioning capability of the radio terminal to a radio terminal connected to the own station ( A transmission / reception unit 110), a reception unit (transmission / reception unit 110) that receives the terminal capability information transmitted from the wireless terminal, and a geographical location of the wireless terminal according to the terminal capability information received by the reception unit. The gist of the present invention is to include a determination unit (capability determination unit 122) that determines whether or not position information indicating a position can be acquired from the wireless terminal.

  According to such a feature, the radio base station can grasp the positioning capability of the radio terminal and can determine whether or not the position information of the radio terminal can be acquired from the radio terminal itself. Therefore, when the position information of the wireless terminal can be acquired from the wireless terminal itself, the process of acquiring the position information of the wireless terminal from the position information server can be omitted, so that signaling occurs between the wireless base station and the position information server. Without increasing network traffic.

  Another feature of the radio base station according to the present invention is that, in the radio base station according to the above feature, the transmitter transmits the capability information transmission request when a radio relay station is a handover candidate of the radio terminal. The gist is to do.

  Another feature of the radio base station according to the present invention is that, in the radio base station according to the above feature, the transmitter transmits relay station capability information indicating the positioning capability of the radio relay station to the radio relay station. Further transmitting a capability information transmission request for requesting transmission, wherein the receiving unit further receives the relay station capability information transmitted from the radio relay station, and the determining unit is configured to receive the relay station received by the receiving unit. The gist is to further determine whether or not position information indicating a geographical position of the radio relay station can be acquired from the radio relay station according to capability information.

  Another feature of the radio base station according to the present invention is that, when it is determined in the radio base station according to the above feature that position information can be acquired from each of the radio terminal and the radio relay station, the radio base station An acquisition unit (location information acquisition unit 123) that acquires location information from each of the terminal and the radio relay station; and a handover control unit that controls handover of the radio terminal based on the location information acquired by the acquisition unit Furthermore, the gist of the handover control unit is to regulate a handover to the radio relay station when a change amount of a relative distance between the radio terminal and the radio relay station exceeds a predetermined amount.

  Another feature of the radio base station according to the present invention is that, in the radio base station according to the above feature, the transmitter performs a measurement process for collecting radio quality information and position information using a radio terminal. The gist is to transmit the capability information transmission request.

  Another feature of the radio base station according to the present invention is that, in the radio base station according to the above feature, a selection unit that selects a radio terminal to be used for the measurement processing from a plurality of radio terminals connected to the own station ( A terminal selection unit 127), wherein the transmission unit transmits the capability information transmission request to the plurality of wireless terminals, and the determination unit receives the terminal capability information received by the reception unit from the plurality of wireless terminals. Accordingly, the gist is to determine a positioning capability for each of the plurality of radio terminals, and the selection unit selects a radio terminal to be used for the measurement process according to the determined positioning capability.

  A feature of the control method according to the present invention is a control method for a radio base station, which is a capability information transmission for requesting a radio terminal connected to the own station to transmit terminal capability information indicating the positioning capability of the radio terminal. A position indicating a geographical position of the wireless terminal according to the step of transmitting a request, the step of receiving the terminal capability information transmitted from the wireless terminal, and the terminal capability information received in the receiving step And determining whether information can be acquired from the wireless terminal.

  ADVANTAGE OF THE INVENTION According to this invention, even when a radio base station uses the positional information on a radio | wireless terminal, the radio base station which can suppress the traffic increase of a network, and its control method can be provided.

It is a figure which shows schematic structure of the radio | wireless communications system which concerns on 1st Embodiment. It is a block diagram which shows the structure of the radio | wireless terminal which concerns on 1st Embodiment. It is a block diagram which shows the structure of the relay node which concerns on 1st Embodiment. It is a block diagram which shows the structure of the wireless base station which concerns on 1st Embodiment. It is a block diagram which shows the structure of the movement management apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the operation example 1 of the handover control operation | movement which concerns on 1st Embodiment (the 1). FIG. 6 is a diagram for explaining an operation example 1 of the handover control operation according to the first embodiment (No. 2). It is a figure for demonstrating the operation example 2 of the handover control operation | movement which concerns on 1st Embodiment. It is a figure for demonstrating the operation example 3 of the hand-over control operation | movement which concerns on 1st Embodiment. It is a sequence diagram which shows the whole schematic operation | movement of the radio | wireless communications system which concerns on 1st Embodiment. It is an operation | movement sequence diagram which shows the operation | movement pattern 1 of the radio | wireless communications system which concerns on 1st Embodiment. It is an operation | movement sequence diagram which shows the operation | movement pattern 2 of the radio | wireless communications system which concerns on 1st Embodiment. It is a figure which shows schematic structure of the radio | wireless communications system which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the wireless base station which concerns on 2nd Embodiment. It is a sequence diagram which shows the operation | movement sequence of the radio | wireless communications system which concerns on 2nd Embodiment.

  In the following, a first embodiment, a second embodiment, and other embodiments of the present invention will be described. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

(1) First Embodiment In the first embodiment, (1.1) the configuration of the wireless communication system, (1.2) the operation of the wireless communication system, and (1.3) the effects of the first embodiment will be described in this order. To do.

(1.1) Configuration of Radio Communication System (1.1.1) Schematic Configuration of Radio Communication System FIG. 1 is a diagram illustrating a schematic configuration of the radio communication system 1 according to the first embodiment.

  The radio communication system 1 according to the first embodiment includes a radio base station 100, a radio terminal 200, and a relay node 300 (radio relay station). The wireless communication system 1 is configured based on LTE-Advanced positioned as a fourth generation (4G) mobile phone system, for example.

  The radio base station 100 is a macro base station that forms a cell having a radius of about several hundred meters, for example. The cell formed by the radio base station 100 is a communication area connectable to the radio base station 100. In the example of FIG. 1, the radio base station 100 is installed in a building B and cannot move.

  The radio base station 100 is connected to a backhaul network (not shown). The backhaul network is a wired communication network, and the radio base station 100 can perform inter-base station communication with other radio base stations via the backhaul network.

  The radio terminal 200 and the relay node 300 are located in a cell formed by the radio base station 100. The radio terminal 200 and the relay node 300 are connected to the radio base station 100 by radio.

  The wireless terminal 200 is possessed by the user U and moves as the user U moves. The wireless terminal 200 may be a mobile phone terminal or a card type communication terminal. The wireless terminal 200 connects to the wireless base station 100 and performs direct wireless communication with the wireless base station 100. The radio terminal 200 executes a handover which is a connection destination switching operation. The radio terminal 200 can execute not only handover from one radio base station to another radio base station but also handover from one radio base station to one relay node.

  The wireless terminal 200 measures the wireless quality of the received wireless signal. The radio quality is the received power (RSRP) of a reference signal transmitted periodically, the received quality (RSRQ) of the reference signal, or the like. The radio terminal 200 measures not only the radio quality of the radio signal received from the connection-destination radio base station 100 but also the radio quality of the receivable radio signal.

  The radio terminal 200 periodically measures radio quality. Alternatively, the radio terminal 200 may measure the radio quality when the level of radio quality with the connection-destination radio base station 100 falls below a predetermined level.

  The wireless signal received by the wireless terminal 200 includes an identifier (cell ID) that identifies the transmission source of the wireless signal. The radio terminal 200 reports the radio quality measurement result to the radio base station 100 together with the cell ID. Such a report is referred to as a measurement report in LTE.

  The relay node 300 is installed in the transport device T and moves as the transport device T moves. In FIG. 1, a bus is illustrated as the transport device T. The relay node 300 is a low-power relay base station that is connected to the radio base station 100 by radio and has a radio backhaul. When the radio terminal 200 is connected to the relay node 300, the relay node 300 relays communication between the radio terminal 200 and the radio base station 100. That is, when the radio terminal 200 is connected to the relay node 300, the radio terminal 200 communicates indirectly with the radio base station 100 via the relay node 300.

  The radio base station 100 has a handover decision right for the radio terminal 200 connected to the radio base station 100. When receiving a handover instruction from the radio base station 100, the radio terminal 200 executes a handover to the handover destination designated by the radio base station 100.

  Specifically, the radio base station 100 grasps the radio state of the radio terminal 200 based on the measurement report received from the radio terminal 200, and when there is a need for handover to another radio base station, the radio base station 100 performs handover. A handover request is transmitted via the backhaul network to the previous candidate radio base station. Then, the radio base station 100 receives a response from the handover destination candidate radio base station, and transmits a handover instruction to the radio terminal 200 if the handover destination candidate radio base station can accept the radio terminal 200. To do. The radio terminal 200 completes the handover by disconnecting the connection with the radio base station 100 and then connecting to the handover destination radio base station. Details of such a procedure can be found, for example, in 3GPP TS36.300: “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description”: Figure 10.1.2.1.1 -1 Refer to Intra-MME / Serving Gateway HO.

  Also, the radio base station 100 grasps the radio state of the radio terminal 200 based on the measurement report received from the radio terminal 200, and becomes a handover destination candidate when there is a need for handover to the relay node 300. A handover request is transmitted to the relay node 300. The radio base station 100 receives the response from the handover destination candidate relay node 300, and transmits a handover instruction to the radio terminal 200 if the handover destination candidate relay node 300 can accept the radio terminal 200. The radio terminal 200 completes the handover by disconnecting the connection with the radio base station 100 and then connecting to the relay node 300 that is the handover destination.

  The radio signal transmitted by the relay node 300 mounted on the transport device T reaches the outside of the transport device T. For this reason, if the radio terminal 200 connected to the radio base station 100 outside the transport equipment T has a radio quality level of a radio signal received from the relay node 300 equal to or higher than a predetermined level, the relay node 300 200 candidate handover destinations.

  For example, the radio quality level of the radio signal received by the radio terminal 200 from the relay node 300 is below a certain threshold, and the radio quality level of the radio signal received by the radio terminal 200 from the radio base station 100 is above a certain threshold. For example, the relay node 300 becomes a handover destination candidate of the radio terminal 200.

  When the wireless terminal 200 performs a handover to the relay node 300 installed in the transport equipment T, the communication area formed by the relay node 300 is narrow. Therefore, when the wireless terminal 200 or the relay node 300 moves, the wireless terminal 200 Needs to be handed over from the relay node 300 to the radio base station 100.

  In the example of FIG. 1, when the wireless terminal 200 is located in the vicinity of the transportation device T that is stopped due to a signal waiting and the wireless terminal 200 performs a handover from the wireless base station 100 to the relay node 300, When the device T resumes moving, the radio terminal 200 needs to perform handover from the relay node 300 to the radio base station 100. As a result, the handover from the radio base station 100 to the relay node 300 is wasted.

  On the other hand, when the wireless terminal 200 exists in the transport device T and moves as the transport device T moves, the wireless terminal 200 is connected to the relay node 300, rather than connected to the wireless base station 100. Communication with the radio base station 100 can be performed under good conditions. Specifically, since the relay node 300 has a higher wireless communication function than the wireless terminal 200, the relay node 300 can perform good communication with the wireless base station 100. In addition, since the wireless terminal 200 can perform wireless communication with a small transmission power, it can suppress battery consumption.

  Therefore, the radio base station 100 performs a handover from the radio base station 100 to the relay node 300 based on whether or not the relative distance between the radio terminal 200 and the relay node 300 remains unchanged or small. To control. When the relative distance does not change or is kept small, it can be considered that the wireless terminal 200 exists in the transport device T. Further, when the relative distance does not change or is not kept small, it can be considered that the wireless terminal 200 exists outside the transport device T.

  The core network 700 includes a mobility management device 500 that is a host device of the radio base station 100 and a location information server 600 that manages location information. In LTE, the mobility management device 500 is called an MME (Mobility Management Entity), and the location information server 600 is called an ESMLC (Evolved Serving Mobile Location Centre).

  The location information server 600 collects the arrival time difference of radio signals received from a plurality of radio base stations by each of the radio terminal 200 and the relay node 300, the base station ID included in the radio signal, etc. The location information of each relay node 300 is generated and managed. Refer to Non-Patent Document 1 for details of the location information server 600 (E-SMLC).

(1.1.2) Detailed Configuration of Radio Communication System (1.1.2.1) Configuration of Radio Terminal FIG. 2 is a block diagram showing the configuration of the radio terminal 200.

  As illustrated in FIG. 2, the wireless terminal 200 includes an antenna 201, an antenna 202, a transmission / reception unit 210, a GPS receiver 220, a control unit 230, a storage unit 240, and a battery 250.

  The transmission / reception unit 210 includes a radio unit 211 that processes radio frequency band signals (that is, radio signals), and a baseband unit 212 that processes baseband signals. The transmission / reception unit 210 transmits / receives a radio signal to / from the radio base station 100 or the relay node 300 via the antenna 201.

  The GPS receiver 220 receives signals from GPS satellites via the antenna 202. The control unit 230 is configured using, for example, a CPU, and controls various functions included in the wireless terminal 200. The storage unit 240 is configured using, for example, a memory, and stores various types of information used for controlling the wireless terminal 200 and the like. The battery 250 stores power supplied to each block of the wireless terminal 200.

  The control unit 230 includes a radio quality measurement unit 231, a position measurement unit 232, and a handover execution unit 233.

  The radio quality measurement unit 231 measures the radio quality of radio signals received by the transmission / reception unit 210 regularly or irregularly. The transmission / reception unit 210 transmits a report of measurement results from the radio quality measurement unit 231 to the radio base station 100. As described above, the radio quality is RSRP or RSRQ or the like, but is not limited to the case where the value such as RSRP or RSRQ is transmitted as it is, and an index such as RSRP or RSRQ is transmitted to the radio base station 100 as a measurement result report. May be.

  The position measurement unit 232 measures the position of the wireless terminal 200 based on the signal received by the GPS receiver 220. The transmission / reception unit 210 transmits a report of the positioning result from the position measurement unit 232 to the radio base station 100.

  When the transmission / reception unit 210 receives a handover instruction, the handover execution unit 233 executes a handover to the handover destination specified by the handover instruction.

  Note that the wireless terminal 200 may not include the antenna 202, the GPS receiver 220, and the position measurement unit 232. In this case, the wireless terminal 200 cannot obtain position information by itself.

  Information regarding such positioning capability is stored in advance in the storage unit 240 of the wireless terminal 200. In response to a request from the radio base station 100, the control unit 230 of the radio terminal 200 controls the transmission / reception unit 210 to transmit the positioning capability information stored in the storage unit 240 to the radio base station 100.

(1.1.2.2) Configuration of Relay Node FIG. 3 is a block diagram showing the configuration of relay node 300.

  As illustrated in FIG. 3, the relay node 300 includes an antenna 301, an antenna 302, an antenna 303, a transmission / reception unit 310, a transmission / reception unit 320, a GPS receiver 330, a control unit 340, and a storage unit 350.

  The transmission / reception unit 310 includes a radio unit 311 that processes radio signals, and a baseband unit 312 that processes baseband signals. The transmission / reception unit 310 transmits / receives a radio signal to / from the radio base station 100 via the antenna 301.

  The transmission / reception unit 320 includes a radio unit 321 that processes radio signals, and a baseband unit 322 that processes baseband signals. The transmission / reception unit 320 transmits / receives a wireless signal to / from the wireless terminal 200 via the antenna 302.

  However, the antennas 301 and 302 may be common, and the transmission / reception units 310 and 320 may be common. In that case, a function for controlling switching between transmission and reception is required.

  The GPS receiver 330 receives a signal from a GPS satellite via the antenna 303. The control unit 340 is configured using, for example, a CPU, and controls various functions included in the relay node 300. The storage unit 350 is configured using a memory, for example, and stores various types of information used for controlling the relay node 300 and the like.

  The control unit 340 includes a position measurement unit 341. The position measurement unit 341 measures the position of the relay node 300 based on the signal received by the GPS receiver 330. The transmission / reception unit 310 transmits the report of the positioning result from the position measurement unit 341 to the radio base station 100.

  Note that the relay node 300 may not include the antenna 303, the GPS receiver 330, and the position measurement unit 341. In this case, the relay node 300 cannot obtain position information by itself.

  Information regarding such positioning capability is stored in advance in the storage unit 350 of the relay node 300. The control unit 340 of the relay node 300 controls the transmission / reception unit 310 to transmit the positioning capability information stored in the storage unit 350 to the radio base station 100 in response to a request from the radio base station 100.

(1.1.2.3) Configuration of Radio Base Station FIG. 4 is a block diagram showing the configuration of the radio base station 100.

  As illustrated in FIG. 4, the radio base station 100 includes an antenna 101, a transmission / reception unit 110, a control unit 120, a backhaul communication unit 130, and a storage unit 140.

  The transmission / reception unit 110 includes a radio unit 111 that processes radio signals, and a baseband unit 112 that processes baseband signals. The transmission / reception unit 110 transmits / receives a radio signal to / from the radio terminal 200 or the relay node 300 via the antenna 101.

  The control unit 120 is configured using, for example, a CPU, and controls various functions included in the radio base station 100. The backhaul communication unit 130 communicates with other radio base stations via the backhaul network. The storage unit 140 is configured using, for example, a memory, and stores various types of information used for controlling the radio base station 100 and the like.

  The control unit 120 includes a capability information acquisition unit 121, a capability determination unit 122, a position information acquisition unit 123, a movement distance calculation unit 124, a relative distance calculation unit 125, and a handover control unit 126.

  The capability information acquisition unit 121 includes information indicating the positioning capability of the wireless terminal 200 connected to the own station (hereinafter referred to as terminal capability information) and information indicating the positioning capability of the relay node 300 connected to the own station (hereinafter referred to as relay node capability). Information).

  The capability determination unit 122 determines whether the location information of the wireless terminal 200 connected to the own station can be acquired from the wireless terminal 200 according to the terminal capability information. Further, the capability determining unit 122 determines whether or not the position information of the relay node 300 connected to the own station can be acquired from the relay node 300 according to the relay node capability information.

  The position information acquisition unit 123 acquires position information from each of the wireless terminal 200 and the relay node 300 when it is determined that position information can be acquired from each of the wireless terminal 200 and the relay node 300. Specifically, the position information acquisition unit 123 acquires the position information of the wireless terminal 200 based on a positioning result report received by the transmission / reception unit 110 from the wireless terminal 200. Further, the position information acquisition unit 123 acquires the position information of the relay node 300 based on the positioning result report received by the transmission / reception unit 110 from the relay node 300.

  The movement distance calculation unit 124 calculates a value indicating the movement distance of the wireless terminal 200 over a predetermined time and a value indicating the movement distance of the relay node 300 over a predetermined time. Details of the movement distance calculation operation by the movement distance calculation unit 124 will be described later.

  The relative distance calculation unit 125 calculates a value indicating the change amount of the relative distance between the wireless terminal 200 and the relay node 300 over a predetermined time based on the position information acquired by the position information acquisition unit 123. The relative distance calculation unit 125 corresponds to a first calculation unit. Details of the relative distance calculation operation by the relative distance calculation unit 125 will be described later.

  The handover control unit 126 performs control related to handover. For example, the handover control unit 126 determines a handover destination and generates a message related to the handover.

  The handover control unit 126 is a message for instructing handover from the radio base station 100 to the relay node 300 by the radio terminal 200 when the value indicating the change amount of the relative distance calculated by the relative distance calculation unit 125 is equal to or less than the threshold value. Is generated. The transmission / reception unit 110 transmits the message to the wireless terminal 200. The handover control unit regulates handover from the radio base station 100 to the relay node 300 by the radio terminal 200 when a value indicating the amount of change in the relative distance between the radio terminal 200 and the relay node 300 exceeds a threshold value. Details of the handover control operation by the handover control unit 126 will be described later.

  When the relay node 300 is a candidate for handover of the radio terminal 200, the control unit 120 requests the radio terminal 200 connected to the radio base station 100 to transmit terminal capability information indicating the positioning capability of the radio terminal 200. The transceiver 110 is controlled to transmit a Capability Request message (capability information transmission request). When the relay node 300 is a handover candidate for the radio terminal 200, the control unit 120 requests the relay node 300 connected to the radio base station 100 to transmit terminal capability information indicating the positioning capability of the relay node 300. The transceiver 110 is controlled to transmit a Capability Request message.

(1.1.2.4) Configuration of Mobility Management Device FIG. 5 is a block diagram showing the configuration of the mobility management device 500.

  As illustrated in FIG. 5, the mobility management device 500 includes a transmission / reception unit 510, a control unit 520, and a storage unit 530.

  The transmission / reception unit 510 is connected to the backhaul network, and communicates with the radio base station 100 and the location information server 600 via the backhaul network. The transmission / reception unit 510 receives position information of the wireless terminal 200 and the relay node 300 from the position information server 600. The control unit 520 is configured using, for example, a CPU, and controls various functions included in the mobility management device 500. The storage unit 530 is configured using a memory, for example, and stores various types of information used for controlling the mobility management device 500 and the like.

  The control unit 520 includes an information acquisition unit 521, a movement distance calculation unit 522, a relative distance calculation unit 523, and a handover determination unit 524.

  The information acquisition unit 521 acquires position information received from the position information server 600 by the transmission / reception unit 510. The movement distance calculation unit 522 calculates a value indicating the movement distance of each of the wireless terminal 200 and the relay node 300 over a predetermined time. Details of the movement distance calculation operation by the movement distance calculation unit 522 will be described later.

  The relative distance calculation unit 523 calculates a value indicating the amount of change in the relative distance between the wireless terminal 200 and the relay node 300 over a predetermined time based on the position information acquired by the information acquisition unit 521. Details of the relative distance calculation operation by the relative distance calculation unit 523 will be described later.

  The handover determining unit 524 makes a determination regarding handover. Specifically, the handover determining unit 524 determines whether or not the handover of the radio terminal 200 to the relay node 300 is permitted.

(1.2) Operation of Radio Communication System Hereinafter, the operation of the radio communication system 1 according to the first embodiment will be described.

(1.2.1) Handover Control Operation The radio base station 100 or the mobility management device 500 acquires the position information of each of the radio terminal 200 and the relay node 300, and performs handover of the radio terminal 200 using the acquired position information. Control.

  In the following, regarding such a handover control operation, (1.2.1.1) Operation Example 1, (1.2.1.2) Operation Example 2, and (1.2.1.3) Operation Example 3 will be described. These will be described in order.

(1.2.1.1) Operation example 1
6 and 7 are diagrams for explaining an operation example 1 of the handover control operation.

  As shown in FIG. 6 and FIG. 7, at timing 0 in a state where the level of radio quality between the radio terminal 200 and the relay node 300 is higher than the level of radio quality between the radio terminal 200 and the radio base station 100. The radio base station 100 or the mobility management device 500 acquires the position information A (X1, Y1, Z1) of the relay node 300 and the position information B (X2, Y2, Z2) of the radio terminal 200. Here, the position information is defined by the X coordinate, the Y coordinate, and the Z coordinate, but the Z coordinate (vertical direction) is not necessarily included in the position information.

  Timing t in a state in which the wireless quality level between the wireless terminal 200 and the relay node 300 is higher than the wireless quality level between the wireless terminal 200 and the wireless base station 100 after a predetermined time has elapsed from the timing 0. In this case, the radio base station 100 or the mobility management device 500 transmits the position information A ′ (X1 ′, Y1 ′, Z1 ′) of the relay node 300 and the position information B ′ (X2 ′, Y2 ′, Z2 ′) of the radio terminal 200. ) And get.

  The radio base station 100 or the movement management device 500 calculates the distance between A and A ′ as the movement distance (MDA) of the relay node 300 using the calculation formula shown in FIG. 6, and the distance between B and B ′. Is calculated as the moving distance (MDB) of the wireless terminal 200.

  When at least one of the movement distance (MDA) of the relay node 300 or the movement distance (MDB) of the radio terminal 200 is greater than zero, the radio base station 100 or the mobility management device 500 performs A according to the calculation formula illustrated in FIG. , B is calculated, and relative distance 2 (RD2) is calculated between A ′ and B ′. Further, the radio base station 100 or the mobility management device 500 calculates a difference (for example, | RD1−RD2 |) between the relative distance 1 (RD1) and the relative distance 2 (RD2). The relative distance difference calculated in this way indicates the amount of change in the relative distance between the radio terminal 200 and the relay node 300 over a predetermined time (period 0 to t).

  When the difference between the relative distance 1 (RD1) and the relative distance 2 (RD2) is equal to or smaller than the threshold value, the radio base station 100 transmits an instruction for handover from the radio base station 100 to the relay node 300 to the radio terminal 200. Thereby, the radio terminal 200 executes a handover from the radio base station 100 to the relay node 300.

  On the other hand, when both the movement distance (MDA) of the relay node 300 and the movement distance (MDB) of the radio terminal 200 are zero, the radio base station 100 or the mobility management device 500 may have been after a predetermined time has elapsed since the timing t. Thus, the position information A of the relay node 300 at the timing 2t in a state where the level of radio quality between the radio terminal 200 and the relay node 300 is higher than the level of radio quality between the radio terminal 200 and the radio base station 100. "(X1", Y1 ", Z1") and position information B "(X2", Y2 ", Z2") of the wireless terminal 200 are acquired.

  The radio base station 100 or the movement management device 500 calculates the distance between A and A ″ as the movement distance (MDA ′) of the relay node 300, and calculates the distance between B and B ″ as the movement distance (MDB ′ of the radio terminal 200). ). When at least one of the movement distance (MDA ′) of the relay node 300 or the movement distance (MDB ′) of the radio terminal 200 is greater than zero, the radio base station 100 or the mobility management device 500 determines that the relative distance 1 between A and B is 1 (RD1) is calculated, and a relative distance 2 (RD2 ′) between A ″ and B ″ is calculated. Further, the radio base station 100 or the mobility management device 500 calculates a difference (for example, | RD1−RD2 ′ |) between the relative distance 1 (RD1) and the relative distance 2 (RD2 ′). When the difference is equal to or smaller than the threshold, the radio base station 100 transmits an instruction for handover from the radio base station 100 to the relay node 300 to the radio terminal 200.

  Thus, the radio base station 100 has a higher radio quality level between the radio terminal 200 and the relay node 300 than the radio quality level between the radio terminal 200 and the radio base station 100, and the relative distance. When the value of the amount of change (difference) is less than or equal to the threshold, control is performed so that the radio terminal 200 performs a handover from the radio base station 100 to the relay node 300.

  Also, the radio base station 100 changes the relative distance even if the radio quality level between the radio terminal 200 and the relay node 300 is higher than the radio quality level between the radio terminal 200 and the radio base station 100. When the amount (difference) value is larger than the threshold value, control is performed so that the radio terminal 200 does not execute (restrict) handover from the radio base station 100 to the relay node 300.

  By performing such handover control, a handover to the relay node 300 is executed when the radio terminal 200 exists in the transport device T, and a relay node when the radio terminal 200 does not exist in the transport device T. The handover to 300 can be prevented from being executed.

  In addition, when the moving distances of the wireless terminal 200 and the relay node 300 are zero, it is difficult to determine whether the wireless terminal 200 exists in the transport device T. By calculating the value of the change (difference) in the relative distance when at least one of the moving distances is greater than zero, the accuracy of determining whether or not the wireless terminal 200 exists in the transport device T is improved. To do.

(1.2.1.2) Operation example 2
FIG. 8 is a diagram for explaining an operation example 2 of the handover control operation.

  As shown in FIG. 8, the radio quality level between the radio terminal 200 and the relay node 300 is the radio base station 100 or moving at the first time when the radio terminal 200 is in a state in which the radio terminal 200 can be connected to the relay node 300. The management device 500 acquires the position information A (X1, Y1, Z1) of the relay node 300. The state in which the wireless terminal 200 can be connected to the relay node 300 is, for example, that the wireless quality level between the wireless terminal 200 and the relay node 300 is higher than the wireless quality level between the wireless terminal 200 and the wireless base station 100. Also means good condition.

  At a second time after the elapse of a predetermined time from the first time, the radio base station 100 or the mobility management device 500 transmits the position information A ′ (X1 ′, Y1 ′, Z1 ′) of the relay node 300 and the radio terminal 200. The position information B (X2, Y2, Z2) of is acquired.

  The radio base station 100 or the movement management device 500 calculates the distance between A and A ′ as the movement distance (MDA) of the relay node 300 using the calculation formula shown in FIG.

  When the movement distance (MDA) of the relay node 300 is greater than zero, the radio base station 100 or the movement management device 500 uses the calculation formula illustrated in FIG. 8 to calculate the relative value between A ′ and B at the second time. Calculate the distance (RD). Here, it differs from the operation example 1 described above in that the relative distance between the wireless terminal 200 and the relay node 300 at the first time is regarded as zero. That is, since the transmission power of the relay node 300 is small, it can be estimated that the radio terminal 200 is located in the vicinity of the relay node 300 when the radio terminal 200 is in a state where it can be connected to the relay node 300. Therefore, the relative distance between the wireless terminal 200 and the relay node 300 at the first time can be regarded as zero.

  The relative distance (RD) between A ′ and B indicates the amount of change in the relative distance between the wireless terminal 200 and the relay node 300 over a predetermined time (first time to second time).

  When the relative distance (RD) between A ′ and B is equal to or less than the threshold, the radio base station 100 or the mobility management device 500 allows (affirms) handover from the radio base station 100 to the relay node 300 by the radio terminal 200. to decide. The threshold value is a value corresponding to a predetermined distance from the relay node 300 (for example, a range in the transport equipment T) as shown by a circle centered on the relay node 300 in FIG. When allowing the handover, the radio base station 100 instructs the radio terminal 200 to perform a handover to the relay node 300.

  When the movement distance (MDA) of the relay node 300 is zero, the radio base station 100 or the movement management device 500 further determines the position of the relay node 300 at a third time after a predetermined time has elapsed since the second time. Get information A ″ (X1 ″, Y1 ″, Z1 ″). As described above, when the movement distance (MDA) of the relay node 300 is zero, the radio base station 100 or the mobility management device 500 repeats acquisition of the position information of the relay node 300 a predetermined number of times.

  By performing such handover control, as in the first operation example, when the radio terminal 200 is present in the transport device T, the handover to the relay node 300 is executed, and the radio terminal 200 is placed in the transport device T. If it does not exist, the handover to the relay node 300 can be prevented from being executed.

(1.2.1.3) Operation example 3
FIG. 9 is a diagram for explaining an operation example 3 of the handover control operation.

  As shown in FIG. 9, the radio quality level between the radio terminal 200 and the relay node 300 is the radio base station 100 or moving at the first time when the radio terminal 200 is in a state in which the radio terminal 200 can be connected to the relay node 300. The management device 500 acquires the position information A (X1, Y1, Z1) of the relay node 300. The state in which the wireless terminal 200 can be connected to the relay node 300 is, for example, that the wireless quality level between the wireless terminal 200 and the relay node 300 is higher than the wireless quality level between the wireless terminal 200 and the wireless base station 100. Also means good condition.

  At a second time after the elapse of a predetermined time from the first time, the radio base station 100 or the mobility management device 500 transmits the position information A ′ (X1 ′, Y1 ′, Z1 ′) of the relay node 300 and the radio terminal 200. The position information B (X2, Y2, Z2) of is acquired.

  The radio base station 100 or the mobility management device 500 calculates the distance between A and A ′ as the movement distance (MDA) of the relay node 300 using the calculation formula shown in FIG. Calculated as the moving distance (MDB) of the wireless terminal 200. Here, the relative distance between the radio terminal 200 and the relay node 300 at the first time is regarded as zero, and the position of the radio terminal 200 at the first time is equal to the position of the relay node 300. This is different from the operation example 1 described above. That is, since the transmission power of the relay node 300 is small, it can be estimated that the radio terminal 200 is located in the vicinity of the relay node 300 when the radio terminal 200 is in a state where it can be connected to the relay node 300. Therefore, the relative distance between the wireless terminal 200 and the relay node 300 at the first time can be regarded as zero.

  When at least one of the movement distance (MDA) of the relay node 300 or the movement distance (MDB) of the radio terminal 200 is larger than zero, the radio base station 100 or the mobility management device 500 uses the calculation formula shown in FIG. Then, the relative distance (RD) between A ′ and B at the second time is calculated. Since the relative distance between the wireless terminal 200 and the relay node 300 at the first time is regarded as zero, the calculated relative distance (RD) between A ′ and B is a predetermined time (from the first time to the first time). The change amount of the relative distance between the radio terminal 200 and the relay node 300 over the second time) is shown.

  When the relative distance (RD) between A ′ and B is equal to or less than the threshold, the radio base station 100 or the mobility management device 500 allows (affirms) handover from the radio base station 100 to the relay node 300 by the radio terminal 200. to decide. The threshold value is a value corresponding to a predetermined distance from the relay node 300 (for example, a range in the transport equipment T) as shown by a circle centered on the relay node 300 in FIG. When allowing the handover, the radio base station 100 instructs the radio terminal 200 to perform a handover to the relay node 300.

  Note that when the moving distance (MDA) of the relay node 300 and the moving distance (MDB) of the radio terminal 200 are zero, the radio base station 100 or the mobility management device 500 further determines the first after a predetermined time has elapsed from the second time. At time 3, position information A ″ (X1 ″, Y1 ″, Z1 ″) of the relay node 300 and position information B ′ (X2 ′, Y2 ′, Z2 ′) of the wireless terminal 200 are acquired. As described above, when the movement distance (MDA) of the relay node 300 and the movement distance (MDB) of the radio terminal 200 are zero, the radio base station 100 or the mobility management device 500 determines that the relay node 300 and the radio terminal 200 The acquisition of position information is repeated a predetermined number of times.

  By performing such handover control, as in the first operation example, when the radio terminal 200 is present in the transport device T, the handover to the relay node 300 is executed, and the radio terminal 200 is placed in the transport device T. If it does not exist, the handover to the relay node 300 can be prevented from being executed.

(1.2.2) Operation Sequence of Radio Communication System Next, regarding the operation sequence of the radio communication system 1 according to the first embodiment, (1.2.2.1) Overall schematic operation, (1.2.2) .2) Operation Pattern 1 and (1.2.2.3) Operation Pattern 2 will be described in this order.

(1.2.2.1) Overall Schematic Operation FIG. 10 is a sequence diagram showing the overall schematic operation of the wireless communication system 1 according to the first embodiment. Here, it is assumed that each of the radio terminal 200 and the relay node 300 connected to the radio base station 100 is in a communication execution state (RRC Connected state).

  As shown in FIG. 10, in step S <b> 11, the radio base station 100 transmits information related to radio quality measurement control in the radio terminal 200 to the radio terminal 200.

  In steps S12 and S13, the radio base station 100 transmits and receives packet data, which is data other than control data used for communication control, to and from the radio terminal 200 and the relay node 300. Transmission / reception of packet data is continued thereafter.

  In step S <b> 14, the radio base station 100 transmits a Capability Request message (capability information transmission request) for requesting transmission of terminal capability information indicating the positioning capability of the radio terminal 200 to the radio terminal 200.

  In step S <b> 15, the radio base station 100 transmits a Capability Request message (capability information transmission request) for requesting transmission of terminal capability information indicating the positioning capability of the relay node 300 to the relay node 300.

  In step S <b> 16, the radio terminal 200 transmits a Capability Indication message (terminal capability information) indicating the positioning capability of the radio terminal 200 to the radio base station 100 in response to the Capability Request message from the radio base station 100.

  In step S <b> 17, the relay node 300 transmits a Capability Indication message (relay station capability information) indicating the positioning capability of the relay node 300 to the radio base station 100 in response to the Capability Request message from the radio base station 100.

  In step S18, the radio base station 100 stores the capability information indicated by the Capability Indication message from the radio terminal 200 and the capability information indicated by the Capability Indication message from the relay node 300.

  In step S <b> 19, the radio base station 100 allocates radio resources to be used for reporting the radio quality measurement result in the radio terminal 200 to the radio terminal 200 and transmits information (UL allocation) indicating the allocation result to the radio terminal 200. .

  In step S <b> 20, the radio terminal 200 measures the radio quality of the received radio signal according to the control from the radio base station 100 and transmits a Measurement Report message indicating the measurement result to the radio base station 100.

  In step S <b> 21, the radio base station 100 determines whether or not the radio terminal 200 needs to be handed over based on the Measurement Report message from the radio terminal 200. Specifically, for example, the radio base station 100 compares the radio quality corresponding to the radio base station 100 with the radio quality corresponding to another node (other radio base station or the relay node 300), If the radio quality corresponding to the node is better than the radio quality corresponding to the radio base station 100, it is determined that the radio terminal 200 needs to be handed over.

  In step S22, the radio base station 100 determines whether or not the handover destination (handover target) of the radio terminal 200 is the relay node 300. For example, the radio base station 100 determines whether or not the handover target is the relay node 300 based on the cell ID included in the Measurement Report message. When the handover target is the relay node 300, the process proceeds to the subsequent processes.

  In step S23, the radio base station 100 determines whether or not the position information of the radio terminal 200 can be acquired from the radio terminal 200 according to the capability information stored in step S18, and the position information of the relay node 300. It is determined whether or not it can be acquired from.

  When it is determined that the position information can be acquired from each of the wireless terminal 200 and the relay node 300, an operation according to an operation pattern 1 described later is started. The operation pattern 1 is an operation pattern in which the radio base station 100 mainly performs the handover control in any of the operation examples 1 to 3 described above.

  On the other hand, when it is determined that the position information cannot be acquired from each of the wireless terminal 200 and the relay node 300, the operation according to the operation pattern 2 described later is started. The operation pattern 2 is an operation pattern in which the mobility management device 500 mainly performs the handover control in any of the operation examples 1 to 3 described above.

(1.2.2.2) Operation pattern 1
FIG. 11 is an operation sequence diagram showing an operation pattern 1 of the wireless communication system 1 according to the first embodiment. Here, it is assumed that the handover control operation according to the operation example 1 described above is performed.

  In step S <b> 101, the radio base station 100 transmits a location information request for requesting transmission of positioning result information to the radio terminal 200.

  In step S102, the radio base station 100 transmits a position information request for requesting transmission of positioning result information to the relay node 300.

  In step S103, when receiving the position information request, the radio terminal 200 performs positioning and transmits a position information report indicating the positioning result to the radio base station 100.

  In step S104, when receiving the position information request, the relay node 300 performs positioning and transmits a position information report indicating the positioning result to the radio base station 100.

  In step S <b> 105, the radio base station 100 stores the position information of the radio terminal 200 based on the position information report from the radio terminal 200. Further, the radio base station 100 stores the position information of the relay node 300 based on the position information report from the relay node 300.

  In step S106, the radio base station 100 measures a certain time. After a predetermined time has elapsed, in step S107, the radio base station 100 transmits information regarding measurement control to the radio terminal 200.

  In step S <b> 108, the radio base station 100 allocates radio resources used for reporting the measurement result of radio quality in the radio terminal 200 to the radio terminal 200 and transmits allocation information (UL allocation) to the radio terminal 200.

  In step S <b> 109, the radio terminal 200 measures the radio quality of the received radio signal according to control from the radio base station 100, and transmits a measurement report (Measurement Report message) to the radio base station 100.

  In step S110, the radio base station 100 determines whether or not the radio terminal 200 needs to be handed over based on the measurement report received from the radio terminal 200 in step S115. Specifically, for example, the radio base station 100 compares the radio quality corresponding to the radio base station 100 with the radio quality corresponding to the relay node 300, and the radio quality corresponding to the relay node 300 is higher than the radio quality. If it is better than the radio quality corresponding to the station 100, it is determined that the radio terminal 200 needs to be handed over to the relay node 300. When it is determined that the radio terminal 200 needs to be handed over to the relay node 300, the process proceeds to the subsequent processes.

  In step S111, the radio base station 100 transmits a location information request to the radio terminal 200.

  In step S112, the radio base station 100 transmits a position information request to the relay node 300.

  In step S113, when receiving the position information request, the radio terminal 200 performs positioning again and transmits a position information report indicating the positioning result to the radio base station 100.

  In step S114, when receiving the position information request, the relay node 300 performs positioning again and transmits a position information report indicating the positioning result to the radio base station 100.

  Here, after the radio base station 100 receives the position information report from the radio terminal 200 and the relay node 300, the radio base station 100 receives the position information from the radio terminal 200 and the relay node 300 by re-requesting the position information from the radio base station 100. The time until receiving again is a predetermined time.

  In step S115, the radio base station 100 calculates the movement distances of the radio terminal 200 and the relay node 300, respectively. If both movement distances of the wireless terminal 200 and the relay node 300 are 0, the process returns to step S106. However, the number of times that the radio base station 100 can repeat this process is limited, and this number is set to a predetermined number (see FIG. 7). If the moving distance of at least one of the wireless terminal 200 and the relay node 300 is greater than 0, the process proceeds to step S116.

  In step S116, the radio base station 100 calculates the relative distance 1 from the position information of the radio terminal 200 and the relay node 300 stored in step S105, and based on the position information report received in steps S113 and S114. The distance 2 is calculated. Then, the radio base station 100 calculates the difference between the relative distance 1 and the relative distance 2.

  If the difference between the relative distance 1 and the relative distance 2 is equal to or smaller than the threshold value in step S117, the radio base station 100 determines a handover from the radio base station 100 to the relay node 300 in step S118, and the radio base station 100 An instruction for handover to relay node 300 is transmitted to radio terminal 200. On the other hand, when the difference between the relative distance 1 and the relative distance 2 is larger than the threshold value in step S117, the radio base station 100 cancels the handover from the radio base station 100 to the relay node 300.

(1.2.2.3) Operation pattern 2
FIG. 12 is an operation sequence diagram showing an operation pattern 2 of the wireless communication system 1 according to the first embodiment. Here, it is assumed that the handover control operation according to the operation example 2 or 3 described above is performed.

  In step S201, the radio base station 100 transmits a handover request message to the relay node 300. When the radio base station 100 determines that the handover target is the relay node 300, a determination request message for requesting a handover determination is transmitted to the mobility management device 500 without transmitting a handover request message to the relay node 300. You can send it.

  In step S202, the relay node 300 transmits a determination request message to the mobility management device 500 in order to have the core network 700 determine the handover in response to the handover request message from the radio base station 100. When the relay node 300 is connected to the core network 700, the radio base station 100 can confirm that the judgment request message to the mobility management device 500 has been transmitted because the radio base station 100 is connected.

  In step S203, the radio base station 100 stops the timer related to the handover when the determination request message to the mobility management device 500 passes through the own station. The radio base station 100 performs processing for enabling the radio terminal 200 to make a radio quality measurement request after a predetermined time.

  In step S204, the mobility management device 500 receives the determination request message. In step S <b> 205, the mobility management device 500 transmits a location information request message requesting location information of the relay node 300 to the location information server 600.

  In steps S206 and S207, the location information server 600 measures the location information of the relay node 300 in response to the location information request message.

  In step S <b> 208, the location information server 600 transmits the location information measurement result to the mobility management device 500.

  In step S209, the mobility management device 500 holds the position information of the relay node 300.

  In step S210, the mobility management device 500 waits for a predetermined interval to elapse.

  In step S <b> 211, the mobility management device 500 transmits a location information request message for requesting location information of each of the relay node 300 and the wireless terminal 200 to the location information server 600.

  In steps S212 to S214, the location information server 600 that has received the location information request message measures the location information of each of the relay node 300 and the wireless terminal 200.

  In step S <b> 215, the location information server 600 transmits the location information measurement result to the mobility management device 500.

  It is assumed that the time from when the location information notification (step S208) arrives at the mobility management device 500 first from the location information server 600 until the next location information notification (step S215) arrives is a predetermined time.

  In step S218, the movement management device 500 calculates the movement distance according to the above-described operation example. Regarding the operation example 2, when the moving distance of the relay node 300 is 0, the process returns to step S209, and steps S209 to S215 are repeated. For operation example 3, when the movement distances of the wireless terminal 200 and the relay node 300 are 0, the process returns to step S209, and steps S209 to S215 are repeated. However, the number of times that the mobility management apparatus 500 can repeat this process is limited, and this number is set to a predetermined number.

  After a predetermined number of times or after re-notification of the position information, for the operation example 2, when the movement management device 500 determines that the movement distance of the relay node 300 is not 0, each of the wireless terminal 200 and the relay node 300 The relative distance is calculated from the position information. For operation example 3, the mobility management device 500 calculates the relative distance from the position information of each of the wireless terminal 200 and the relay node 300 when the traveling distance of each of the wireless terminal 200 and the relay node 300 is not zero.

  If the calculated relative distance is less than or equal to the threshold, the mobility management device 500 determines that the handover from the radio base station 100 to the relay node 300 by the radio terminal 200 is permitted (affirmed), and the calculated relative distance is If it is determined that the threshold is equal to or greater than the threshold, it is determined that the handover from the radio base station 100 to the relay node 300 by the radio terminal 200 is rejected (denied).

  In step S219, the mobility management apparatus 500 transmits information on the determination result to the radio base station 100.

  On the other hand, in step S216, the radio base station 100 allocates resources so that the radio terminal 200 can notify the radio base station 100 of the measurement result of radio quality.

  In step S217, the radio terminal 200 notifies the radio base station 100 of the measurement result of the radio quality according to the instruction from the radio base station 100. The measurement result includes information on the wireless quality between the wireless terminal 200 and the relay node 300.

  In step S220, the radio base station 100 determines the radio base station 100 by the radio terminal 200 based on the determination result information received from the mobility management device 500 in step S219 and the measurement result received from the radio terminal 200 in step S217. Determines whether to execute a handover from the relay node 300 to the relay node 300.

  Here, the radio base station 100 determines that the handover result by the mobility management device 500 is permitted (affirmed), and the radio terminal station 100 has a good radio quality between the radio terminal 200 and the relay node 300. It is determined that the handover from the radio base station 100 to the relay node 300 by 200 is executed. When it is determined that the handover is to be executed, whether or not the relay node 300 can accept is confirmed, and thereafter, an instruction for handover to the relay node 300 is transmitted to the radio terminal 200.

(1.3) Effects of First Embodiment As described above, according to the first embodiment, the radio base station 100 has a radio quality level between the radio terminal 200 and the relay node 300 that is less than the radio terminal 200. If the value of the change amount (difference) in the relative distance is larger than the threshold value even if it is higher than the wireless quality level between the wireless base station 100 and the wireless base station 100, handover from the wireless base station 100 to the relay node 300 is Control is performed so that the radio terminal 200 is not executed.

  By performing such handover control, a handover to the relay node 300 is executed when the radio terminal 200 exists in the transport device T, and a relay node when the radio terminal 200 does not exist in the transport device T. Since it is possible not to execute the handover to 300, it is possible to prevent the processing load and the communication delay due to the useless handover.

  In particular, a handover from the radio base station 100 to the relay node 300 has a larger overhead than a handover between radio base stations. According to the first embodiment, since the probability of handover from the radio base station 100 to the relay node 300 can be reduced, overhead can be suppressed.

  Further, when the movement distances of both the radio terminal 200 and the radio base station 100 are zero, the value of the change amount (difference) of the relative distance is not calculated, and at least one of the radio terminal 200 and the radio base station 100 is calculated. By calculating the value of the change amount (difference) in the relative distance when the movement distance becomes greater than zero, the determination accuracy can be improved.

  In the first embodiment, the handover control unit 126, when the level of radio quality between the radio terminal 200 and the relay node 300 is higher than the level of radio quality between the radio terminal 200 and the radio base station 100, The position information request is transmitted to the wireless terminal 200 and the relay node 300. That is, when the level of radio quality between the radio terminal 200 and the relay node 300 is equal to or lower than the level of radio quality between the radio terminal 200 and the radio base station 100, the handover control unit 126 Is not transmitted to the radio terminal 200 and the relay node 300.

  As a result, the location information report can be transmitted to the radio terminal 200 and the relay node 300 only when the handover needs to be performed. Therefore, compared with the case where the radio terminal 200 and the relay node 300 regularly transmit the position information report, overhead can be reduced.

  In the operation example 2 or 3 according to the first embodiment, when the handover target is the relay node 300, it is assumed that there is no relative distance between the radio terminal 200 and the relay node 300 (zero), so that the handover request Since the method of measuring the position information of the wireless terminal 200 at the time when the communication is performed can be omitted, the calculation related to the handover can be reduced.

  Further, according to the operation example 2 or 3, when the relay node 300 is moving, the relay node 300 is based on the relative distance between the relay node 300 and the radio terminal 200 at the position after the predetermined time in the relay node 300. By controlling the handover to 300, the process of calculating the moving distance of the radio terminal 200 can be reduced.

  In the first embodiment, the position information is measured by the core network 700 (specifically, the position information server 600), so that the position information can be measured by the wireless terminal 200 alone such as GPS or the relay node 300 alone. The control signal between the radio terminal 200, the radio base station 100, and the core network 700 can be reduced, and the traffic load can be reduced.

  In the first embodiment, the radio base station 100 can select an appropriate operation pattern from among the operation patterns 1 and 2 described above according to the positioning capabilities of the radio terminal 200 and the relay node 300. That is, the radio base station 100 grasps the positioning capabilities of the radio terminal 200 and the relay node 300, determines whether or not the position information of the radio terminal 200 can be acquired from the radio terminal 200 itself, and also determines the position information of the relay node 300. Is determined from the relay node 300 itself.

  Therefore, when the location information of the radio terminal 200 can be acquired from the radio terminal 200 itself, the radio base station 100 can omit the process of acquiring the location information of the radio terminal 200 from the location information server 600. Further, when the position information of the relay node 300 can be acquired from the relay node 300 itself, the process of acquiring the position information of the relay node 300 from the position information server 600 can be omitted. Therefore, according to the operation pattern 1, signaling does not occur between the radio base station 100 and the location information server 600, and an increase in network traffic can be suppressed.

(2) Second Embodiment In the second embodiment, a case will be described in which measurement processing for collecting radio quality information and position information is performed using the radio terminal 200. Such a technique is called MDT (Minimization of Drive Test).

  In a wireless communication system, after a wireless base station 100 is installed, when a building is built around it or the installation status of the peripheral base station changes, the wireless propagation environment around the wireless base station 100 changes.

  For this reason, conventionally, radio quality information related to a radio propagation environment is regularly collected using a measurement vehicle equipped with measurement equipment. Specifically, the wireless quality is measured at each position in the communication area by the measurement vehicle.

  Such a collection method has a problem that man-hours are high and costs are high. In response to this problem, the MDT attempts to automate the collection work using the user's wireless terminal 200 (see 3GPP TR36.805 and TS37.320).

(2.1) Overall Configuration of Radio Communication System FIG. 13 is a diagram illustrating a schematic configuration of the radio communication system 1 according to the second embodiment. In FIG. 13, the mobility management device 500 and the location information server 600 described in the first embodiment are not shown.

  As illustrated in FIG. 13, the radio communication system 1 according to the second embodiment includes a radio base station 100 and a plurality of radio terminals 200. The wireless communication system 1 is configured based on LTE-Advanced positioned as a fourth generation (4G) mobile phone system, for example.

  The radio base station 100 is a macro base station that forms a cell having a radius of about several hundred meters, for example. The cell formed by the radio base station 100 is a communication area connectable to the radio base station 100. The radio base station 100 is connected to a backhaul network (not shown).

  The radio terminal 200 is located in a cell formed by the radio base station 100 and communicates by connecting to the radio base station 100 by radio.

  The wireless terminal 200 is possessed by the user U and moves as the user U moves. The wireless terminal 200 may be a mobile phone terminal or a card type communication terminal.

  Each wireless terminal 200 measures the wireless quality of the received wireless signal. The radio quality is the received power (RSRP) of a reference signal transmitted periodically, the received quality (RSRQ) of the reference signal, or the like. The radio terminal 200 measures not only the radio quality of the radio signal received from the connection-destination radio base station 100 but also the radio quality of the receivable radio signal. The radio terminal 200 periodically measures radio quality. Alternatively, the radio terminal 200 may measure the radio quality when the level of radio quality with the connection-destination radio base station 100 falls below a predetermined level.

  Each wireless terminal 200 has a system that can measure position information by itself, such as GPS, and a wireless terminal 200 that does not have such a positioning system. When acquiring the position information for the wireless terminal 200 that does not have the positioning system, the wireless base station 100 needs to acquire the position information from the position information server 600. Therefore, the wireless base station 100 and the position information server Signaling is generated with 600. In addition, an idle wireless terminal cannot measure an accurate position.

  The radio base station 100 collects radio quality information and position information using the radio terminal 200 according to the MDT configuration. Here, when the wireless terminal 200 that does not have a positioning system such as GPS is used for MDT, it leads to an increase in network (backhaul) traffic due to signaling. In addition, an idle wireless terminal cannot measure an accurate position. Therefore, a wireless terminal to be used for MDT is selected based on the position measurement capability (positioning capability) possessed by the wireless terminal.

(2.2) Configuration of Radio Base Station FIG. 14 is a block diagram showing a configuration of the radio base station 100 according to the second embodiment.

  As illustrated in FIG. 14, the radio base station 100 according to the second embodiment includes an antenna 101, a transmission / reception unit 110, a control unit 120, a backhaul communication unit 130, and a storage unit 140.

  The transmission / reception unit 110 includes a radio unit 111 that processes radio signals, and a baseband unit 112 that processes baseband signals. The transmission / reception unit 110 transmits / receives a wireless signal to / from the wireless terminal 200 via the antenna 101.

  The control unit 120 is configured using, for example, a CPU, and controls various functions included in the radio base station 100. The backhaul communication unit 130 communicates with other radio base stations via the backhaul network. The storage unit 140 is configured using, for example, a memory, and stores various types of information used for controlling the radio base station 100 and the like.

  The control unit 120 includes a capability information acquisition unit 121, a capability determination unit 122, a terminal selection unit 127, and a measurement control unit 128.

  The capability information acquisition unit 121 acquires information (terminal capability information) indicating the positioning capability of the wireless terminal 200 connected to the own station.

  The capability determination unit 122 determines whether the location information of the wireless terminal 200 connected to the own station can be acquired from the wireless terminal 200 according to the terminal capability information. The capability determination unit 122 determines, for each of the plurality of radio terminals 200, whether or not the location information can be acquired by the radio terminal according to the terminal capability information from the plurality of radio terminals 200.

  The terminal selection unit 127 selects the wireless terminal 200 used for the measurement process (MDT) based on the determination result by the capability determination unit 122.

  The measurement control unit 128 controls measurement of radio quality information and position information by the radio terminal 200.

(2.3) Operation of Radio Communication System FIG. 15 is a sequence diagram showing an operation sequence of the radio communication system 1 according to the second embodiment.

  As illustrated in FIG. 15, in step S301, the radio base station 100 confirms whether or not to start a measurement process using MDT. The measurement process by MDT may be performed periodically or according to an instruction from the operator's server. When starting the measurement process by MDT, the process proceeds to step S302.

  In step S <b> 302, the radio base station 100 transmits a Capability Request message (capability information transmission request) requesting transmission of terminal capability information indicating the positioning capability of the radio terminal 200 to each radio terminal 200.

  In step S <b> 303, each radio terminal 200 transmits a Capability Indication message (terminal capability information) indicating the positioning capability of the terminal itself to the radio base station 100 in response to the Capability Request message from the radio base station 100.

  In step S <b> 304, the radio base station 100 determines what position measurement capability (positioning capability) the radio terminal 200 has according to the terminal capability information from each radio terminal 200. Then, the radio base station 100 selects the radio terminal 200 to be used for measurement processing (MDT) based on the positioning capability information of the radio terminal 200.

  In step S305, the radio base station 100 transmits information on radio quality information and position information measurement control (MDT indication) to the radio terminal 200 used for measurement processing (MDT).

  The radio terminal 200 used for the measurement process (MDT) measures the radio quality and position of the radio signal received according to the control from the radio base station 100, and indicates a measurement result when requested by the network. Is transmitted to the radio base station 100. The radio base station 100 transmits the radio quality information and the position information collected in this way to the server of the operator or uses them for adjusting the communication parameters of the own station.

(2.4) Effects of Second Embodiment As described above, according to the second embodiment, the radio base station 100 includes, for example, a positioning system such as GPS among the plurality of radio terminals 200. By selecting the existing wireless terminal 200 and using it for MDT, the process of acquiring the position information of the wireless terminal 200 from the position information server 600 can be omitted. Accordingly, an increase in network (backhaul) traffic due to signaling with the location information server 600 can be suppressed. Even when MDT is performed using a wireless terminal in an idle state, an accurate position can be measured.

(3) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the above-described embodiment, the wireless communication system based on LTE-Advanced has been illustrated. However, the wireless communication system is not limited to LTE-Advanced. For example, a wireless communication system based on mobile WiMAX (IEEE 802.16e) is used. The present invention may be applied.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

  DESCRIPTION OF SYMBOLS 100 ... Wireless base station, 101 ... Antenna, 110 ... Transmission / reception part, 111 ... Radio | wireless part, 120 ... Control part, 121 ... Capability information acquisition part, 122 ... Baseband part, 122 ... Capability discrimination | determination part, 123 ... Position information acquisition part , 124: movement distance calculation unit, 125 ... relative distance calculation unit, 126 ... handover control unit, 127 ... terminal selection unit, 128 ... measurement control unit, 130 ... backhaul communication unit, 140 ... storage unit, 200 ... wireless terminal, 201 ... antenna, 202 ... antenna, 210 ... transmission / reception unit, 211 ... radio unit, 212 ... baseband unit, 220 ... GPS receiver, 230 ... control unit, 231 ... radio quality measurement unit, 232 ... position measurement unit, 233 ... Handover execution unit, 240 ... storage unit, 250 ... battery, 300 ... relay node, 301, 302, 303 ... antenna, 310, 320 Transmission / reception unit, 312 ... baseband unit, 320 ... transmission / reception unit, 321 ... radio unit, 322 ... baseband unit, 330 ... GPS receiver, 340 ... control unit, 341 ... position measurement unit, 350 ... storage unit, 500 ... movement Management device, 510 ... transmission / reception unit, 520 ... control unit, 521 ... information acquisition unit, 522 ... movement distance calculation unit, 523 ... relative distance calculation unit, 524 ... handover determination unit, 530 ... storage unit, 600 ... position information server, 700: Core network

Claims (5)

A control unit, the control unit,
Processing for transmitting a capability information transmission request for requesting transmission of terminal capability information to a wireless terminal connected to the own station;
Processing for receiving the terminal capability information transmitted from the wireless terminal;
Receiving measurement report information including reception quality of the reference signal measured by the wireless terminal or radio quality information indicating the reception quality of the reference signal; and
The terminal capability information includes information indicating whether or not the mobile terminal has a positioning system that measures location information without a network assistance,
Terminal capability information thus received, including the the wireless terminal, and wherein the radio quality information and the location information in the idle state is measured by the positioning system as measured in the idle state of the wireless terminal to the Measurement Report Information Used to determine whether to set the MDT measurement process to be transmitted ,
The radio base station , wherein the MDT measurement process includes a process in which the radio terminal periodically acquires the radio quality information .   The radio base station according to claim 1, wherein the control unit executes a process of transmitting the capability information transmission request when performing the MDT measurement process. A control unit, the control unit,
A process of receiving a capability information transmission request for requesting transmission of terminal capability information from a connected radio base station;
In response to receiving the capability information transmission request, a process of transmitting the terminal capability information to the radio base station;
Processing for transmitting Measurement Report information including the reception power of the reference signal transmitted from the radio base station or the radio quality information indicating the reception quality of the reference signal,
The terminal capability information includes information indicating whether or not the mobile terminal has a positioning system that measures location information without a network assistance,
The transmitted terminal capability information, including with respect to the radio terminal, the position information measured by the positioning system in the idle state and the radio quality information measured in the idle state of the radio terminal to the Measurement Report Information Used to determine whether to set the MDT measurement process to be transmitted ,
The MDT measurement process includes a process in which the wireless terminal periodically acquires the wireless quality information . The wireless terminal according to claim 3, wherein, when the MDT measurement process is set, the control unit executes a process of transmitting position information measured by the positioning system by including the measurement report information in the measurement report information . A processor provided in a wireless terminal,
A process of receiving a capability information transmission request for requesting transmission of terminal capability information from a connected radio base station;
In response to receiving the capability information transmission request, a process of transmitting the terminal capability information to the radio base station;
Processing for transmitting Measurement Report information including the reception power of the reference signal transmitted from the radio base station or the radio quality information indicating the reception quality of the reference signal,
The terminal capability information includes information indicating whether or not the mobile terminal has a positioning system that measures location information without a network assistance,
The transmitted terminal capability information, including with respect to the radio terminal, the position information measured by the positioning system in the idle state and the radio quality information measured in the idle state of the radio terminal to the Measurement Report Information Used to determine whether to set the MDT measurement process to be transmitted ,
The MDT measurement process includes a process in which the wireless terminal periodically acquires the wireless quality information .

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