JP6402634B2 - Base station equipment - Google Patents

Description

  The present invention relates to a base station apparatus.

  Currently, communication systems such as mobile phone systems and wireless local area networks (LANs) are widely used. In the field of mobile communications, there is ongoing discussion on next-generation communication technology in order to further improve communication speed, communication capacity, and communication quality. For example, the standardization organization 3GPP (3rd Generation Partnership Project) has completed or studied the standardization of a communication standard called LTE (Long Term Evolution) and a communication standard called LTE-A (LTE-Advanced) based on LTE. ing.

  Regarding such a communication system, there is a technique called HetNet (Heterogeneous Network). HetNet is a technology in which, for example, systems having different cell radii and wireless communication methods are mixed in the same service area. Thereby, for example, compared to a communication system other than HetNet, the capacity (or capacity) of the entire network can be improved.

  However, HetNet currently has a service area narrower than the macro cell (hereinafter sometimes referred to as “pico cell”) within the service area of the macro cell base station (hereinafter sometimes referred to as “macro cell”). It is used in the meaning of a communication system in which picocell base stations are arranged in a hierarchy (or multiple layers).

  In a communication system in a hetnet environment, even when a terminal device moves within a macro cell, a cell switching process (or handover process) from a macro cell to a pico cell or from a pico cell to a macro cell may be performed.

  For this reason, the number of handover processes may increase in a communication system under a Hetnet environment as compared with communication systems other than Hetnet. Therefore, in the communication system under the Hetnet environment, the number of control signals exchanged between the base station and the control device is increased as compared with the communication system other than the Hetnet, and the base station and MME (Mobility Management Entity) in the wired network are increased. In some cases, the processing load of each device increases.

  As a technique related to such a communication system, for example, there are the following techniques.

  That is, in a communication system including a macro station, a local station, and a terminal device, the local station generates a measurement signal used for measurement in the terminal device based on the user identifier and transmits the measurement signal to the terminal device. Based on the identifier, the received measurement signal is measured.

  According to this technology, for example, it is possible to provide a communication system that provides highly efficient small cell radio access.

  Also, a method for setting an X2 interface in a mobile communication system in which the first base station transmits an X2 interface setting request message to the second base station, and the second base station transmits an X2 interface response message to the first base station. There is a technology.

  According to this technique, for example, an X2 interface is set between home base stations, and the UE can move between home base stations.

JP, 2014-30132, A Special table 2013-526207 gazette

  However, in a technique for generating a measurement signal based on a user identifier and a technique for transmitting an X2 interface setting request message from the first base station to the second base station, the number of control signals increases at the time of handover in Hetnet. There is no mention of that.

  Therefore, with these two technologies, when a terminal performs handover from a macro cell to a pico cell or from a pico cell to a macro cell in Hetnet, the processing load may increase in each device in the wired network.

  Therefore, one disclosure is to provide a base station apparatus that suppresses an increase in the number of control signals exchanged between apparatuses in a wired network.

  One disclosure is to provide a base station apparatus that suppresses an increase in processing load in each apparatus in a wired network.

  A terminal device that includes a second service area formed by another base station device, forms a first service area that is wider than the second service area, and is wireless with a terminal device that is in the first service area In a base station apparatus that performs communication, identification information of the other base station apparatus exchanged between the base station apparatus and another apparatus connected by wire, and the other base station apparatus as the base station apparatus There is provided a control unit for changing from the first identification information to be identified to second identification information for identifying each service area formed for each antenna that transmits or receives a radio signal in the base station apparatus.

  According to one disclosure, it is possible to provide a base station apparatus configured to suppress an increase in the number of control signals exchanged between apparatuses in a wired network. In addition, according to one disclosure, it is possible to provide a base station apparatus configured to suppress an increase in processing load in each apparatus in the wired network.

FIG. 1 is a diagram illustrating a configuration example of the communication system 10. FIG. 2 is a diagram illustrating a configuration example of the communication system 10. FIG. 3 is a diagram illustrating a configuration example of the communication system 10. FIG. 4 is a diagram illustrating a configuration example of the base station apparatus. FIG. 5 is a diagram illustrating a sequence example in the communication system. FIG. 6 is a flowchart showing an operation example in the base station apparatus. FIG. 7A shows an example of an attribute information table, and FIG. 7B shows an example of an attribute change table. FIG. 8 is a diagram illustrating a relationship example between the eNB ID and the Cell ID. FIG. 9A illustrates an example of E-CGI, and FIG. 9B illustrates an example of E-CGI ′. FIG. 10 is a diagram illustrating a configuration example of the communication system 10. FIG. 11A and FIG. 11B are diagrams illustrating examples of differences between the normal mode and the macro subordinate mode. FIG. 12 is a flowchart showing an operation example in the base station apparatus. FIG. 13 is a diagram showing processing differences depending on whether loop setting is ON or OFF and whether or not a HO request is received. FIG. 14 is a diagram illustrating a sequence example in the communication system. FIG. 15 is a diagram illustrating a sequence example in the communication system. FIG. 16 is a diagram illustrating a sequence example in the communication system. FIG. 17 is a diagram illustrating a sequence example in the communication system. FIG. 18 is a diagram illustrating a sequence example in the communication system. FIG. 19 is a diagram illustrating a sequence example in the communication system. FIG. 20 is a diagram illustrating a configuration example of a base station apparatus.

  Hereinafter, modes for carrying out the present invention will be described.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration example of a communication system 10 according to the first embodiment. The communication system 10 includes a base station device 100-1, another base station device 100-2, a terminal device 200, and another device 600.

  The base station apparatus 100-1 forms a first service area 100-M. On the other hand, the other base station apparatus 100-2 forms a second service area 100-P. The first service area 100-M includes the second service area 100-P, and is wider than the second service area 100-P.

  Thus, in the communication system 10, the first service area 100-M and the second service area 100-P are arranged hierarchically. A communication system in which service areas (or cells) are hierarchically arranged in this way may be referred to as “Hetnet”, for example.

  The base station device 100-1 performs wireless communication with the terminal device 200 located in the first service area 100-M. On the other hand, the other base station device 100-2 also performs wireless communication with the terminal device 200 when the terminal device 200 is in the second service area 100-P. The terminal device 200 can receive various services such as a call service by wireless communication.

  The base station apparatus 100-1 includes a control unit 122. The control unit 122 performs the second identification from the first identification information to the identification information of the other base station apparatus 100-2 exchanged between the base station apparatus 100-1 and another apparatus 600 connected by wire. Change to information.

  The first identification information is, for example, identification information that identifies another base station device 100-2 from the base station device 100-1.

  Further, the second identification information is identification information for identifying each service area formed for each antenna that transmits or receives a radio signal in the base station apparatus 100-1, for example. As the second identification information, for example, there is identification information for identifying each sector in the base station apparatus 100-1.

  The identification information in the other base station apparatus 100-2 is changed to, for example, identification information for identifying each sector in the base station apparatus 100-1. By such a change, in the other apparatus 600 and the base station apparatus 100-1, it can be considered that the terminal apparatus 200 hands over the sector in the base station apparatus 100-1. In this case, the base station apparatus 100-1 may not exchange control signaling with another apparatus 600 at the time of handover.

  Since base station apparatus 100-1 does not need to exchange control signaling with other apparatuses 600, it is possible to suppress an increase in the number of control signals in the wired section. Further, by suppressing the increase in the number of control signals, the other devices 600 and the base station devices 100-1 and 100-2 in the wired section can also suppress an increase in processing.

[Second Embodiment]
Next, a second embodiment will be described.

<Configuration example of communication system>
FIG. 2 is a diagram illustrating a configuration example of the communication system 10. The communication system 10 includes a macro cell base station (hereinafter sometimes referred to as a macro base station) 100-1, a pico cell base station (hereinafter sometimes referred to as a pico base station) 100-2, and a terminal device (hereinafter referred to as a terminal). 200). The communication system 10 also includes an MME (Mobility Management Entity) 300 and an S-GW (Serving-Gateway) 400. An EPC (Evolved Packet Core) 500 includes an MME 300 and an S-GW 400.

  The macro base station 100-1 forms a service area 100-M. The service area 100-M indicates a communicable range in the macro base station 100-1, for example. The macro base station 100-1 performs wireless communication with the terminal 200 located in the service area 100-M, and provides the terminal 200 with various services such as a call service and a web page browsing service. The example of FIG. 2 represents an example in which the terminal 200 is located in the service area 100-M.

  The pico base station 100-2 forms a service area 100-P. The service area 100-P indicates a communicable range in the pico base station 100-1, for example. The pico base station 100-2 performs wireless communication with the terminal 200 located in the service area 100-P and provides various services such as a call service to the terminal 200.

  The service area 100-P of the pico base station 100-2 is narrower than the service area 100-M of the macro base station 100-2, and the service area 100-P is hierarchically arranged in the service area 100-M. ing. The communication system 10 in which the service areas 100-M and 100-P are hierarchically arranged in this way may be referred to as “Hetnet”, for example.

  The service area 100-M of the macro base station 100-1 may be referred to as a macro cell 100-M. Alternatively, the macro base station 100-1 and its service area 100-M may be collectively referred to as a macro cell 100-1.

  Further, the service area 100-P of the pico base station 100-2 may be referred to as a pico cell 100-P. Alternatively, the pico base station 100-2 and its service area 100-P may be collectively referred to as a pico cell 100-2. Furthermore, the base stations 100-1 and 100-2 may be referred to as cells 100-1 and 100-2, for example.

  The macro base station 100-1 and the pico base station 100-2 can exchange user data, control messages, and the like through the X2 interface.

  The terminal 200 is, for example, a portable mobile terminal such as a smartphone, a feature phone, or a tablet, or a personal computer. The terminal 200 performs wireless communication with the macro base station 100-1 in the macro cell 100-M, and receives various services from the macro base station 100-1. In addition, the terminal 200 performs radio communication with the pico base station 100-2 in the pico cell 100-P, and receives various services from the pico base station 100-2.

  The MME 300 performs, for example, location management of the terminal 200 and processing for a control signal (C-Plane (Control-Plane)) between the two base stations 100-1 and 100-2 and the terminal 200.

  For example, the S-GW 400 performs processing such as relaying user data (U-Plane (User-Plane)) exchanged between the terminal 200 and the host device, and determining a route for the user data.

  The two base stations 100-1, 100-2 and the MME 300 exchange control messages and the like through the S1 interface, and the two base stations 100-1, 100-2 and S-GW 400 also exchange user data and the like through the S1 interface. To do.

  FIG. 3 illustrates a configuration example of the communication system 10. In the example of FIG. 3, a configuration example of the communication system 10 in which a plurality of macro base stations 100-11 to 100-13 is connected to the EPC 500 is illustrated. FIG. 3 shows an example in which a plurality of pico base stations 100-21 to 100-28 are arranged in each of the macro cells 100-12M to 100-13M.

  As illustrated in FIG. 3, the communication system 10 may include a plurality of macro base stations 100-11 to 100-13 and a plurality of pico base stations 100-21 to 100-28.

<Configuration example of base station>
Next, a configuration example of the base stations 100-1 and 100-2 will be described. Since both the macro base station 100-1 and the pico base station 100-2 have the same configuration, the macro base station 100-1 and the pico base station 100-2 are collectively described as the base station 100.

  FIG. 4 shows a configuration example of the base station 100. The base station 100 includes an antenna 101, a radio unit 110, and a control / baseband unit 120.

  Antenna 101 transmits the radio signal output from radio section 110 to terminal 200. In addition, the antenna 101 receives a radio signal transmitted from the terminal 200 and outputs the received radio signal to the radio unit 110.

  The radio unit 110 includes a modem unit 111, a transmission unit 112, a PA (Power Amp) 113, a DUP (Duplexer) 114, an LNA (Low Noise Amp) 115, and a reception unit 116.

  The modem 111 performs modulation processing on the baseband signal output from the control / baseband unit 120 and outputs the modulated baseband signal to the transmitter 112. Further, the modem unit 111 performs demodulation processing on the baseband signal output from the receiving unit 116, and outputs the demodulated baseband signal to the control / baseband unit 120. Examples of modulation processing and demodulation processing include QPSK (Quadrature Phase Shift Keying) and 16-QAM (Quadrature Amplitude Modulation).

  The transmission unit 112 converts the baseband signal output from the modulation / demodulation unit 111 into a wireless signal in the wireless band, and outputs the converted wireless signal to the PA 113. The transmission unit 112 may include, for example, a frequency conversion circuit or an LPF (Low Pass Filter).

  PA 113 is an amplifier that amplifies the radio signal output from transmission section 112 and outputs the amplified signal to DUP 114.

  The DUP 114 outputs the radio signal output from the PA 113 to the antenna 101, and outputs the radio signal received from the antenna 101 to the LNA 115.

  The LNA 115 is a low noise amplifier and amplifies the radio signal received from the DUP 114.

  The receiving unit 116 converts the radio signal output from the LNA 115 into a baseband signal in the baseband band, and outputs the converted baseband signal to the modem unit 111. The receiving unit 116 may also include, for example, a frequency conversion circuit.

  The control / baseband unit 120 includes an interface unit 121, a control unit 122, a baseband unit 123, a power supply unit 124, and a timing control unit 125.

  The interface unit 121 converts the control signal and user data received from the control unit 122 into X2 interface and S1 interface packet data, and outputs the packet data to other base stations, the MME 300, and the S-GW 400. The interface unit 121 receives packet data from other base stations, the MME 300, and the S-GW 400, extracts a control signal and user data from the packet data, and outputs the control signal and user data to the control unit 122.

  The control unit 122 outputs user data received from the interface unit 121 to the baseband unit 123, and outputs user data received from the baseband unit 123 to the interface unit 121. The control unit 122 terminates the control signal received from the interface unit 121 or newly generates a control signal and outputs the control signal to the baseband unit 123 or the interface unit 121.

  For example, the control unit 122 determines radio resource allocation, modulation scheme, and the like when performing radio communication with the terminal 200, generates a control signal including these scheduling results, and transmits the control signal via the baseband unit 123 and the like. To the terminal 200. Based on this control signal, terminal 200 performs radio communication with base station 100, and base station 100 also performs radio communication with terminal 200 according to the scheduling result determined by itself.

  The baseband unit 123 receives user data and a control signal from the control unit 122, performs error correction coding processing on the user data and the like, and outputs the result as a baseband signal to the radio unit 110. The baseband unit 123 performs error correction decoding processing on the baseband signal received from the radio unit 110 to extract user data, control signals, and the like, and extracts the extracted user data and control signals. Output to the control unit 122.

  The power supply unit 124 turns on or off the power supply of the base station 100 under the control of the control unit 122. In addition, the timing control unit 125 controls timing for outputting user data and the like from the control unit 122 to the interface unit 121 and the baseband unit 123. Thereby, for example, radio signals, packet data, and the like are output from the base station 100 to the terminal 200, and from the base station 100 to other base stations, the MME 300, and the S-GW 400 at a predetermined timing.

  The memory 126 stores attribute information and an attribute change table of the macro base station 100-1 and the pico base station 100-2. Details of the attribute information and the attribute change table will be described later. The control unit 122 can perform processing by appropriately referring to attribute information and an attribute change table stored in the memory 126. Details of the processing will be described later.

<Operation example>
Next, an operation example in the second embodiment will be described. Operation examples will be described in the following order.

1. Whole sequence example 2. Example of processing in base station Case study <1. Overall Sequence Example> describes an overall operation example performed in the communication system 10. As an operation example, as illustrated in FIG. 2, an example in which the terminal 200 performs handover from the macro base station 100-1 to the pico base station 100-2 will be described.

  <2. Example of Processing in Base Station> describes an example of operation in the macro base station 100-1. Also in this case, as illustrated in FIG. 2, an example in which the terminal 200 performs handover from the macro base station 100-1 to the pico base station 100-2 will be described.

  Finally, <3. Case Study>, an example in which the terminal 200 performs handover from the pico base station 100-2 to the macro base station 100-1 in addition to the handover from the macro base station 100-1 to the pico base station 100-2 will be described. .

<1. Overall sequence example>
FIG. 5 shows a sequence example of the entire communication system 10. The terminal 200 is located in the service area 100-M of the macro base station 100-1, performs radio communication with the macro base station 100-1, and exchanges user data and the like (S10). The macro base station 100-1 communicates with the S-GW 400 and exchanges user data and the like (S11).

  The terminal 200 measures the communication quality of the radio section with respect to the macro base station 100-1 and the pico base station 100-2, and transmits a measurement report message (hereinafter sometimes referred to as MRM) including the measurement result to the macro base station 100. -1 (S12).

  Next, when the communication quality included in the MRM satisfies the handover condition, the macro base station 100-1 determines to perform handover from the local station 100-1 to the pico base station 100-2 (S13). For example, the control unit 122 receives the MRM via the baseband unit 123 or the like, and regarding the communication quality included in the MRM, the communication quality of the macro base station 100-1 is equal to or less than a threshold, and the communication of the pico base station 100-2 When the quality is equal to or higher than the threshold, it is determined to perform handover to the pico base station 100-2.

  Next, the macro base station 100-1 transmits a handover request to the pico base station 100-2 that is a handover destination (S14). For example, when determining that the terminal 200 is to be handed over to the pico base station 100-2, the control unit 122 generates a handover request and transmits the handover request to the pico base station 100-2 via the interface unit 121.

  Next, the macro base station 100-1 transmits a HO (Hand Over) instruction to instruct the terminal 200 to perform handover to the pico base station 100-2 (S15). For example, the control unit 122 generates a control signal indicating the HO instruction, and transmits the control signal indicating the HO instruction to the terminal 200 via the baseband unit 123 or the like.

  Next, the macro base station 100-1 transfers (or forwards) untransmitted user data addressed to the terminal 200 to the pico base station 100-2, and also transfers terminal information regarding the terminal 200 to the pico base station 100-2 ( Or forwarding) (S16). For example, the following processing is performed. That is, the control unit 122 determines user data that has not received an ACK signal from the terminal 200 as user data to be forwarded, and transmits the user data to the pico base station 100-2 via the interface unit 121. In addition, the control unit 122 reads the terminal information held in the memory 126 and transmits it to the pico base station 100-2 via the interface unit 121.

  The processes from S18 to S21 are processes such as path switching performed in the EPC 500 by the handover of the terminal 200, for example. In the second embodiment, the processing from S18 to S23 is not performed. This is because, in the macro base station 100-1, the attribute information of the pico base station 100-2 that is the handover destination is transferred from the pico base station to the virtual sector in the macro base station 100-1 based on the attribute change table. Make changes that are considered. With this change, the macro base station 100-1 controls the MME 300 at the time of handover because the handover destination base station is not the pico base station 100-2 but a virtual sector in the macro base station 100-1. There is no need to send a signal. Details of the processing are described in <2. An example of processing in the base station> will be described.

  Also, the macro base station 100-1 and the pico base station 100-2 perform loop setting, for example, from the S-GW 400 to the terminal 200 via the macro base station 100-1 and the pico base station 100-2. A route is set (S30 to S32). User data and the like are exchanged through the route set by the loop setting. Details of the processing are described in <2. An example of processing in the base station> will be described.

<2. Example of processing in base station>
Next, an example of processing in the base station 100 will be described. FIG. 6 illustrates an example of processing in the base station 100. 6 will be described using the macro base station 100-1 as an example of the base station 100.

  When receiving the MRM, the macro base station 100-1 starts processing (S40).

  Next, the macro base station 100-1 confirms PCI (Physical Cell Identification) and determines whether or not the handover destination cell is the pico cell 100-2 arranged in the own station 100-1 (S41).

  FIG. 7A is a diagram illustrating an example of the attribute information table 1261 stored in the memory 126. The attribute information table 1261 stores attribute information of the macro base station 100-1 and the pico base station 100-2. The attribute information includes, for example, PCI and E-CGI (E-UTRAN Cell Global Identification) for each of the base stations 100-1 and 100-2. For example, PCI is used to identify the base station 100 in the wireless section, and E-CGI is used to identify the base station 100 in the wired section.

  PCI is identification information for identifying each base station (or each cell) 100, for example. In the example of FIG. 7A, the PCI of the macro cell # 1 (for example, the macro base station 100-1) is “001”, and the PCI of the pico cell # 1 (for example, the pico base station 100-2) is “401”. . FIG. 7B also shows PCI, but each base station 100 has a unique PCI.

  This PCI is included in the MRM, for example. Terminal 200 and base station 100 identify each base station using PCI.

  On the other hand, the E-CGI is identification information for identifying the base station (or cell) 100, for example, and the macro base station 100-1 exchanges identification information of the base station 100 with the EPC 500 (or a wired section). Used when The E-CGI includes eNB ID (evolved Node B Identification) and Cell ID, for example.

  FIG. 8 is a diagram illustrating a relationship example between an eNB ID and a Cell ID. The eNB ID is identification information for identifying the base station (or cell) 100, for example, and is represented by a multi-digit number. In the example of FIG. 8, the eNB ID of the macro cell # 1 (for example, the macro base station 100-1) is “mmmmm... Mm”.

  For example, when there are a plurality of sectors in the base station 100, the Cell ID is identification information for identifying each sector. The sector is, for example, each service area obtained by dividing the service area 100-M by each antenna 101-1 to 101-3 of the base station 100-1. The example of FIG. 8 shows an example in which the service area 100-M is divided into three sectors # 1-1 to # 1-3. In this case, the cell ID “00... 01” is assigned to the sector # 1-1, the cell ID “00... 02” is assigned to the sector # 1-2, and the cell ID “00.・ 03 ”is assigned.

  Although FIG. 7A also shows the Cell ID, the macro cell # 1 and the pico cells # 1 to # 3 do not have a plurality of sectors, for example.・ ・ 00 」.

  For example, the last 8 digits of E-CGI represent Cell ID.

  Returning to FIG. 6, in the present process (S41), for example, the following process is performed. That is, the control unit 122 receives the MRM from the baseband unit 123 and extracts the PCI of the handover destination base station 100-2 from the MRM. The control unit 122 refers to the attribute information table 1261 to determine whether the PCI of the handover destination base station 100-2 is the PCI of the pico cell 100-2 subordinate to the macro cell 100-1.

  For example, in the example of FIG. 7A, if the PCI of the handover destination base station 100-2 included in the MRM is “401”, the control unit 122 determines that it is the pico cell # 1 in the macro cell # 1. To do. On the other hand, when the PCI of the handover destination base station 100-2 included in the MRM is not any of “401” to “403”, the control unit 122 does not use the pico base station 100-2 subordinate to the macro base station 100-1. It is determined that there is no (or not a HetNet environment).

  When the macro base station 100-1 determines that the handover destination base station is a pico base station under its control (Yes in S41), the macro base station 100-1 changes the attribute of the pico cell 100-2 (S42).

  FIG. 7B shows an example of the attribute change table 1262. The attribute change table 1262 stores PCI, E-CGI, and E-CGI ′ information for each base station.

  E-CGI ′ is changed after the E-CGI of the pico base station 100-2 is changed from the E-CGI as the pico base station 100-2 to a virtual sector in the macro base station 100-1. Of E-CGI.

  In the example of FIG. 7B, when E-CGI and E-CGI ′ are compared, the eNB ID of picocell # 1 is the eNB ID “xxx... Xx” of picocell # 1 and the eNB of macrocell # 1. The ID is changed to “mmm... Mm”. Further, the Cell ID of the pico cell # 1 is changed from “00... 00” to “00... 01”. As a result, the E-CGI of picocell # 1 is changed from “xxx... Xx00... 00” to E-CGI ′ “mmm. Also, the E-CGI of picocell # 2 is changed from “yyy... Yy00... 00” to E-CGI “mmm.

  FIGS. 9A and 9B show an example of the relationship between E-CGI and E-CGI ′. 9A shows an example of E-CGI, and FIG. 9B shows an example of E-CGI ′. Here, the meaning of “mmm... Mm00... 01” which is E-CGI ′ of picocell # 1 will be considered.

  The part “00... 01” in the E-CGI ′ of the pico cell # 1 represents, for example, identification information of a sector (for example, sector # 1) in the macro cell having “mmm... Mm” as an eNB ID. ing. Similarly, the “00... 02” portion of the E-CGI ′ of the pico cell # 2 identifies, for example, a sector (eg, sector # 2) in a macro cell having “mmm... Mm” as an eNB ID. Represents information. Further, the “00... 03” portion of the E-CGI ′ of the pico cell # 3 includes, for example, identification information of a sector (for example, sector # 3) in the macro cell having the eNB ID “mmm. Represents.

  That is, it can be said that “mmm... Mm00... 01” represents not the identification information of the pico base station 100-2 but the identification information of the virtual sector in the macro base station 100-1. In addition, it can be said that “mmm... Mm00... 02” is not identification information of the pico base station but represents identification information of a virtual sector in the macro base station 100-1.

  When the terminal 200 is handed over from the macro base station 100-1 to the pico base station 100-2, in the relationship of E-CGI, "mmmm ... mm00 ... 00" to "xxx ... xxx00 ... 00" The terminal 200 has moved to “. On the other hand, in the relationship of E-CGI ′, the terminal 200 is moved from “mmm... Mm00... 00” to “mmm.

  In the E-CGI relationship, the terminal 200 is handed over from the macro base station 100-1 to the pico base station, but in the E-CGI ′ relationship, the terminal 200 starts from a certain sector in the macro base station 100-1. It has been moved to another sector.

  In this case, the terminal 200 can be regarded as moving between sectors within the same macro base station 100-1, and the macro base station 100-1 does not have to report a notification regarding handover to the EPC 500.

  Thereby, for example, the processing as shown in S18 to S23 of FIG. 5, that is, the macro base station 100-1 transmits a message to the wired network side at the time of handover, or receives the message from the wired network side. You don't have to do it.

  Accordingly, in the communication system 10, since the macro base station 100-1 does not have to exchange messages with the wired network side, for example, each device 100-1, 100-2, 300, 400 in the wired network is used. It is also possible to suppress an increase in the number of control signals exchanged with each other. Moreover, in this communication system 10, since the increase of a control signal can be suppressed, for example, the increase in the processing load in each apparatus 300,400 in a wired network can be suppressed.

  In this process (S42 in FIG. 6), for example, the following process is performed. That is, the control unit 122 of the macro base station 100-1 refers to the attribute change table 1262 and reads E-CGI ′ corresponding to the PCI of the pico base station 100-2 that is the handover destination, thereby obtaining the attribute information as E -CGI can be changed to E-CGI '. Based on E-CGI ′, the control unit 122 recognizes that the handover is between sectors in the macro base station 100-1, and proceeds to the next process without transmitting a message to the EPC 500.

  Returning to FIG. 6, next, the macro base station 100-1 sets a loop process (S43).

  FIG. 10 shows an example of user data paths after setting the loop processing. The macro base station 100-1 does not transmit a message regarding handover to the MME 300 or the S-GW 400. Therefore, the route of user data is not changed by the MME 300 or the S-GW 400. Therefore, the macro base station 100-1 itself sets the user data addressed to the terminal 200 received from the EPC 500 to be transmitted to the pico base station 100-2. Also, the pico base station 100-2 sets the initiative of the macro base station 100-1 so that the user data received from the terminal 200 after the handover is transmitted to the macro base station 100-1.

  Such a loop setting is performed as follows, for example. When the control unit 122 of the macro base station 100-1 reads E-CGI ′, the user data addressed to the terminal 200 is not output to the baseband unit 123, but is transmitted to the macro base station 100-1. Information is generated and stored in the memory 126. In addition, the control unit 122 generates a request message for transmitting the user data received from the terminal 200 to the local station (macro base station 100-1) to the pico base station 100-2 serving as a handover destination, and X2 It transmits to the pico base station 100-2 using the interface. When the control unit 122 of the pico base station 100-2 receives the request message via the interface unit 121, the user data whose transmission source is the terminal 200 generates route information to be transmitted to the macro base station 100-1. Store in memory 126.

  Thereafter, the macro base station 100-1 transmits user data addressed to the terminal 200 to the pico base station 100-2 according to the route information. In this case, the pico base station 100-2 transmits user data addressed to the terminal 200 to the terminal 200.

  Also, the pico base station 100-2 transmits user data whose transmission source is the terminal 200 to the macro base station 100-1 according to the route information. In this case, the macro base station 100-1 transmits the user data to the EPC 500.

  Returning to FIG. 6, next, the macro base station 100-1 performs a handover process in the radio section (S44).

  Then, the macro base station 100-1 ends the series of processes (S45).

  On the other hand, when the handover destination base station is not the pico base station 100-2 under its control (No in S41), the macro base station 100-1 performs normal handover processing (S46). The normal handover process is, for example, various processes such as a path switching request (S18), path switching (S20, S21), and relaying of user data (S22, S23) in FIG.

  Then, the macro base station 100-1 ends the series of processes (S45).

  FIGS. 11A and 11B summarize the differences between the two modes. 11A shows the difference between the two modes after the handover process, and FIG. 11B shows the difference between the two modes after the handover process.

  In the “normal mode” (or the first mode), for example, the terminal 200 does not move from the macro base station 100-1 to the pico base station 100-2, and the attribute of the pico base station 100-2 is changed. There is no mode. For example, when the terminal 200 is handed over from one macro cell # 1 to another macro cell # 2.

  On the other hand, in the “macro subordinate mode” (or the second mode), for example, the terminal 200 moves from the macro base station 100-1 to the pico base station 100-2, and the attribute of the pico base station 100-2 is changed. Mode.

  For example, when the macro base station 100-1 determines that the terminal 200 is to be handed over from the macro base station 100-1 to the pico base station 100-2 (eg, S13 in FIG. 5), the macro base station 100-1 changes from “normal mode” to “macro subordinate” Move to “Mode”.

  As shown in FIG. 11A, during the handover process, in the “normal mode”, the PCI of the connection source and the connection destination are used in the wireless section. For example, when the terminal 200 is handed over from one macro cell # 1 to another macro cell # 2, the PCI # 1 of the macro cell # 1 and the PCI # 2 of the macro cell # 2 are used in the radio section.

  On the other hand, in the wireless section, in the “macro subordinate mode”, the PCI of the connection source and the connection destination are used as in the “normal mode”. For example, when the terminal 200 is handed over from the macro base station 100-1 to the pico base station 100-2, the PCI # 1 'of the macro base station 100-1 and the PCI # 2' of the pico base station 100-2 are used.

  In the wired section, in the “normal mode”, the E-CGI of the connection destination cell is used. For example, when the terminal 200 is handed over from one macro cell # 1 to another macro cell # 2, the macro cell # 2 transmits a path switching request to the MME 300 using the E-CGI # 2 of the macro cell # 2.

  On the other hand, in the wired section, in the “macro subordinate mode”, the attribute of the E-CGI is changed, and the control signal is not transmitted to the MME 300 or the like. For example, when the terminal 200 is handed over from the macro base station 100-1 to the pico base station 100-2, the macro base station 100-1 changes the attribute of the E-CGI of the pico base station 100-2 and changes the control signal to Do not send to MME300.

  On the other hand, as shown in FIG. 11B, after the handover process, in the “normal mode”, PCI is used for the synchronization process of the radio section, and C-RNTI is used for resource management of the radio section. For example, when the terminal 200 is handed over from one macro cell # 1 to another macro cell # 2, the terminal 200 performs synchronization processing using the PCI # 2 of the macro cell # 2, and the macro cell # 2 performs C-RNTI (Cell Radio Network Temporary (Identifier) is used to allocate radio resources to the terminal 200.

  Similarly, in the “macro subordinate mode”, PCI is used in the synchronization processing of the radio section, and C-RNTI is used in the radio resource management. For example, when the terminal 200 is handed over from the macro base station 100-1 to the pico base station 100-2, the terminal 200 performs synchronization processing using the PCI # 2 ′ of the pico base station 100-2, and the pico base station 100- 2 allocates radio resources to the terminal 200 using C-RNTI.

  For the wired section, in the “normal mode”, the E-CGI of the connection destination cell is used. For example, when the terminal 200 moves from the macro cell # 1 to the macro cell # 2, the macro cell # 2 transmits user data to the S-GW 400 using the E-CGI # 2 of the own cell.

  For the wired section, in the “macro subordinate mode”, the E-CGI ′ after the attribute change is used. For example, the pico base station 100-2 transmits user data to the S-GW 400 via the macro base station 100-1 using the E-CGI 'received from the macro base station 100-1.

<3. Case Study>
Next, various case studies according to the pattern in which the terminal 200 is handed over will be described. As a pattern in which the terminal 200 is handed over, for example,
3.1 Example when terminal moves from macro cell to pico cell 3.2 Example when terminal moves from pico cell to macro cell 3.3 Example when terminal moves from macro cell to pico cell move to macro cell 3.4 Macro cell Example of a case where a terminal that has moved to a pico cell moves to an adjacent pico cell # 1 under the same macro cell 3.5 3.4 An example of a case where the terminal further moves to an adjacent pico cell # 2 under the same macro cell 3.6. There is an example in which the terminal that has moved to the adjacent pico cell # 1 in 4 moves to the source pico cell.

  FIG. 12 is a flowchart showing an example of the entire process including the above six patterns. The flowchart of FIG. 12 represents the process mainly performed by the macro base station 100-1 and the pico base station 100-2, for example.

  As shown in FIG. 12, when the base stations 100-1 and 100-2 start processing (S50), the base station 100-1 determines to perform handover for the terminal 200 (S51).

  When the base stations 100-1 and 100-2 decide to perform handover (Yes in S51), the base stations 100-1 and 100-2 confirm whether or not the own station has a Hetnet configuration (S52). For example, the base stations 100-1 and 100-2 confirm whether or not the own station has a Hetnet configuration based on the attribute information table 1261.

  When the base stations 100-1 and 100-2 confirm that the base station has a Hetnet configuration (Yes in S52), the base stations 100-1 and 100-2 release the existing path between terminals (S53). For example, the base stations 100-1 and 100-2 release the existing inter-terminal path by stopping assignment of radio resources to the terminal 200.

  Next, the base stations 100-1 and 100-2 determine whether the own station is the macro base station 100-1 or the pico base station 100-2 based on the station attribute identifier (S54).

  For example, the following determination is performed. That is, the macro base station 100-1 determines, based on the attribute information table 1261, whether or not it is a macro base station from a station attribute identifier (for example, PCI or E-CGI) assigned to the own station. Further, in the macro base station 100-1, when the undelivered packet is transferred (for example, S16 in FIG. 5), the own station is a macro base station having a Hetnet configuration, and the base station 100-2 is a pico base station having a Netnet configuration. Notify that there is. Alternatively, at this time, the macro base station 100-1 may notify the E-CGI of the own station and the E-CGI of the base station 100-2. The pico base station 100-2 can determine from the notification that the own station is a Hetnet pico base station.

  When the station attribute identifier is the macro base station 100-1 (“macro (parent)” in S54), the macro base station 100-1 determines whether the loop setting is ON and whether a handover request is transmitted. It is determined whether or not (S55). Depending on the determination result, the macro base station 100-1 performs (Processing B), (Processing C), (Processing D), or (Processing E).

  FIG. 13 summarizes the correspondence between the determination result and each process. In FIG. 13, “Is loop setting ON?” Means that, for example, as shown in FIG. 10, a route from the terminal 200 to the EPC 500 via the pico base station 100-2 and the macro base station 100-1 is set. It represents whether or not.

  “HO request transmission?” Represents, for example, whether or not the macro base station 100-1 is transmitting a handover request (hereinafter also referred to as a HO request) to the pico base station 100-2. Yes.

  As shown in FIG. 13, when the loop setting is OFF and the HO request is transmitted, the macro base station 100-1 performs (Process B). In this case, for example, an example of processing on the macro base station 100-1 side when the terminal 200 is handed over from the macro base station 100-1 to the pico base station 100-2 is shown.

  As shown in FIG. 12, in (Processing B), the macro base station 100-1 newly establishes a loop path (S56) and turns on the loop setting (S57). Thereby, for example, a route as shown in FIG. 10 is set. ON / OFF of the loop setting is performed, for example, by turning ON / OFF the loop setting information stored in a predetermined area of the memory 126 in the control unit 122 of the macro base station 100-1.

  Then, the macro base station 100-1 ends the series of processes (S58).

  On the other hand, as shown in FIG. 13, when the loop setting is ON and the HO request is not transmitted (or when the HO request is received), the macro base station 100-1 performs (Process C). For example, an example of processing on the macro base station 100-1 side when the terminal 200 handed over from the macro base station 100-1 to the pico base station 100-2 hands over from the pico base station 100-2 to the macro base station 100-1 (Pattern of (3.3) above).

  As shown in FIG. 12, in (Processing C), the macro base station 100-1 releases the loop path and turns off the loop path setting (S60, S61). Further, since the terminal 200 is handed over to the macro base station 100-1, the macro base station 100-1 newly establishes an inter-terminal path with the terminal 200 (S62). The opening of the loop path is performed, for example, by deleting the path information of the loop path stored in the memory 126 by the control unit 122 of the macro base station 100-1.

  Then, the macro base station 100-1 ends the series of processes (S58).

  Also, as shown in FIG. 13, when the loop setting is OFF and the HO request is not transmitted (or when the HO request is received), the macro base station 100-1 performs (Processing D). For example, an example of processing on the macro base station 100-1 side when the terminal 200 makes a call connection in the pico base station 100-2 and then the terminal 200 is handed over from the pico base station 100-2 to the macro base station 100-1. (Pattern of (3.2) above).

  As shown in FIG. 12, in (Processing D), the macro base station 100-1 newly establishes an inter-terminal path without performing processing for the loop path (S62). For example, the macro base station 100-1 sets an inter-terminal path for the terminal 200 that has been handed over from the pico base station 100-2.

  Then, the macro base station 100-1 ends the series of processes (S58).

  Furthermore, as illustrated in FIG. 13, when the loop setting is ON and the HO request is neither transmitted nor received, the macro base station 100-1 performs (Processing E). For example, when the terminal 200 handed over from the macro base station 100-1 to the pico base station 100-2 is adjacent to the pico base station 100-2 and handed over to another pico base station in the same macro base station 100-1 An example of processing on the macro base station 100-1 side will be shown (pattern (3.4) above).

  As shown in FIG. 12, in (Processing E), the macro base station 100-1 ends a series of processes without performing any particular process on the loop path or the inter-terminal path (S58). The macro base station 100-1 ends the series of processes without changing the loop setting or the like for the handover from the pico cell 100-2 to the adjacent pico cell.

  On the other hand, in FIG. 12, when the station attribute identifier is the pico base station 100-2 (“pico (child)” in S54), the pico base station 100-2 has the loop setting turned on as in S55. It is determined whether or not a handover request is transmitted (S65). Depending on the determination result, the pico base station 100-2 performs (Processing A), (Processing D), (Processing B), or (Processing F).

  FIG. 13 also shows the correspondence between the determination result in the pico base station 100-2 and each process. As illustrated in FIG. 13, when the loop setting is ON and the HO request is transmitted, the pico base station 100-2 performs (Processing A). For example, an example of processing on the pico base station 100-2 side when the terminal 200 handed over from the macro base station 100-1 to the pico base station 100-2 hands over from the pico base station 100-2 to the macro base station 100-1 (Pattern of (3.3) above).

  As shown in FIG. 12, in (Processing A), the pico base station 100-2 releases the set loop path and turns off the loop setting (S66, S67). For example, the control unit 122 of the pico base station 100-2 deletes the path information stored in the memory 126, and the processing is performed by turning OFF or ON the loop setting information stored in a predetermined area of the memory 126.

  And pico base station 100-2 complete | finishes a series of processes (S58).

  Also, as shown in FIG. 13, when the loop setting is OFF and the HO request is not transmitted (or when the HO request is received), the pico base station 100-2 performs (Processing D). For example, an example of processing on the pico base station 100-2 side when the terminal 200 is handed over from the macro base station 100-1 to the pico base station 100-2 is shown (pattern (3.1) above).

  As shown in FIG. 12, in (Process D), the pico base station 100-2 newly establishes a loop path (S68) and turns on the loop setting (S69). For example, the macro base station 100-1 transfers the route information regarding the set loop route together with the unreached packet to the pico base station 100-2 (for example, S16 in FIG. 5), and the control unit 122 of the pico base station 100-2 sends the route information. By storing information in the memory 126, a loop path is newly established. Also, the pico base station 100-2 sets up an inter-terminal path with the terminal 200 (S70). For example, the pico base station 100-2 performs a process of setting an inter-terminal path for the terminal 200 that has been handed over from the macro base station 100-1.

  And pico base station 100-2 complete | finishes a series of processes (S58).

  Furthermore, as shown in FIG. 13, when the loop path setting is OFF and the HO request is transmitted, the pico base station 100-2 performs (Process B). For example, an example of processing on the pico base station 100-2 side when the terminal 200 makes a call to the pico base station 100-2 and performs call connection, and then the terminal 200 is handed over to the macro base station 100-1. (Pattern of (3.2) above).

  As shown in FIG. 12, in (Processing B), the pico base station 100-2 ends the series of processes without performing the process for the loop path or the process for the inter-terminal path (S58). For example, since the terminal 200 is handed over from the pico base station 100-2 to the macro base station 100-1, the pico base station 100-1 ends a series of processes without performing any particular process.

  Furthermore, as shown in FIG. 13, when the loop setting is OFF and the HO request is neither transmitted nor received, the pico base station 100-2 performs (Process F). For example, the terminal 200 handed over from the macro base station 100-1 to the pico base station 100-2 and further handed over from the pico base station 100-2 to the adjacent pico base station 100-3 is further connected to another adjacent pico base station 100-. 4 shows an example of the pico base station 100-2 side when handing over to 4 (pattern (3.5) above).

  As shown in FIG. 12, in (Processing F), the pico base station 100-2 ends the series of processes without performing the process for the loop path or the process for the inter-terminal path (S58).

  On the other hand, when it is determined that the base stations 100-1 and 100-2 do not have the Hetnet configuration (No in S52), the base stations 100-1 and 100-2 perform normal handover processing.

  Further, even when the base stations 100-1 and 100-2 have not decided to perform handover, when receiving the HO request, the base stations 100-1 and 100-2 determine whether or not the configuration is a Hetnet configuration (S71), and in the case of the Hetnet configuration (S71). Yes), the process proceeds to S54 and the above-described processing is performed. On the other hand, when the base stations 100-1 and 100-2 are not in the Hetnet configuration (No in S71), the base stations 100-1 and 100-2 perform normal handover processing.

  Next, the patterns (3.1) to (3.6) will be described in order.

<3.1 Example when terminal moves from macro cell to pico cell>
FIG. 14 is a diagram illustrating a sequence example when terminal 200 moves (or handovers) from macro cell 100-1 to pico cell 100-2. In the processing shown in FIG. 14, the same processing blocks as in FIG.

  The terminal 200 performs call connection processing for the macro base station 100-1, a route is set between the terminal 200 and the EPC 500 via the macro base station 100-1, and user data is transferred using the route. (S80).

  Thereafter, the macro base station 100-1 determines that the terminal 200 is handed over to the pico base station 100-2 (S12 (S51)), and the subsequent processing is performed.

  In FIG. 14, the process (S52 to S57) performed by the macro base station 100-1 corresponds to the process (process B) from S51 to S57 in FIG.

  In this process, the macro base station 100-1 transfers the station type information to the pico base station 100-2 together with the unreached packet and the terminal information (S16). The station type information is, for example, the above-described station attribute identifier, which is information indicating that the base station 100-1 is a macro base station and the base station 100-2 is a pico base station.

  The macro base station 100-1 is a macro base station (YES in S54), transmits a HO request (YES in S550), and is not set in a loop (NO in S551). The E-CGI is changed and loop setting is performed (S56, S57).

  On the other hand, the processes (S71 to S70) performed by the pico base station 100-2 in FIG. 14 correspond to the processes (process D) from S71 to S70 in FIG.

  That is, since the pico base station 100-2 is a pico base station (pico in S54), receives a HO request (NO in S650), and is not set in a loop (NO in S651), the macro base station 100-2 A loop is set with the station 100-1 (S68, S69). Also, the pico base station 100-2 sets a path for loop setting for the macro base station 100-2 (S81). For example, the loop path may be set based on the route information received from the macro base station 100-1.

  As described above, a route is set between the terminal 200 and the EP 500 via the pico base station 100-2 and the macro base station 100-1, and user data is transferred by this route (S82).

<3.2 Example when terminal moves from pico cell to macro cell>
FIG. 15 is a sequence example when the terminal 200 calls the pico base station 100-2, and then the terminal 200 moves (or handovers) from the pico base station 100-2 to the macro base station 100-1. FIG. 15, the same processing blocks as those in FIG. 12 are denoted by the same reference numerals.

  When terminal 200 makes a call to pico base station 100-2, a route is set between terminal 200 and EPC 500 via pico base station 100-2, and user data is transferred by this route ( S83).

  Thereafter, the pico base station 100-2 determines that the terminal 200 is handed over to the macro base station 100-1 (S51), and the pico base station 100-2 notifies the macro base station 100-1 of the HO request (S141). ), A HO instruction is notified to the terminal 200 (S151). Also, the pico base station 100-2 transfers an unreached packet or the like to the macro base station 100-1 (S161).

  The processing (S52 to S62) performed by the macro base station 100-1 in FIG. 15 corresponds to the processing from S51 to S62 (processing D) in FIG.

  That is, the macro base station 100-1 is a macro base station (YES in S54), receives a HO request (NO in S550), is not set in a loop (NO in S551), and E− There is no change in CGI and no loop setting. In this case, the macro base station 100-1 sets a path for the terminal 200 that has been handed over from the pico base station 100-2 (S84, S62).

  On the other hand, the processing (S51 to S651) performed by the pico base station 100-2 in FIG. 15 corresponds to the processing from S51 to S65 and S58 (processing B) in FIG.

  That is, the pico base station 100-2 has a pico base station type (NO in S54), transmits a HO request (YES in S650), has not been set in a loop (NO in S651), and has a loop setting. Do not do.

  As described above, a route is set between the terminal 200 and the EPC 500 via the macro base station 100-1, and user data and the like are transferred using this route (S85).

<3.3 Example when a terminal that has moved from a macro cell to a pico cell moves to a source macro cell>
FIG. 16 illustrates a sequence example when the terminal 200 that has moved (handed over) from the macro cell 100-1 to the pico cell 100-2 moves (handed over) to the source macro cell 100-1.

  The loop path described above is set from the terminal 200 to the host device via the pico base station 100-2 and the macro base station 100-1 (S82).

  Thereafter, handover is determined in the pico base station 100-2 (S51), and the pico base station 100-2 notifies the HO request to the macro base station 100-1 and the HO instruction to the terminal 200 (S141, S151). . Also, the pico base station 100-2 transfers an unreached packet or the like to the macro base station 100-1 (S161).

  The processing (S52 to S62) performed by the macro base station 100-1 in FIG. 16 corresponds to the processing from S51 to S62 (processing C) in FIG.

  That is, the macro base station 100-1 is a macro base station, receives a HO request (NO in S550), has a loop setting (YES in S651), and opens the loop path and turns off the loop setting. (S60, S61). In this case, the macro base station 100-1 sets up a path with the EPC 500 (S86).

  On the other hand, the process (S51 to S67) performed by the pico base station 100-2 in FIG. 16 corresponds to the process (process A) from S51 to S67 in FIG.

  That is, the pico base station 100-2 has a pico base station type (NO in S54), transmits a HO request (YES in S650), the loop setting is ON (S651), and the loop path is released. Then, the loop setting is turned OFF (S66, S67).

  As described above, a route is set between the terminal 200 and the EPC 500 via the macro base station 100-1, and user data is transferred using the route (S87).

<3.4 Example when a terminal that has moved from a macro cell to a pico cell moves to an adjacent pico cell under the same macro cell>
FIG. 17 illustrates a sequence example when the terminal 200 that has moved (handed over) from the macro cell 100-1 to the pico cell 100-2 moves (handed over) to an adjacent pico cell 100-3 under the same macro cell 100-1.

  A route is set from the terminal 200 to the host device via the pico base station 100-2 and the macro base station 100-1 (S82).

  After that, the pico base station 100-2 determines that the terminal 200 is handed over from the pico base station 100-2 to the adjacent pico base station 100-2 (S51), and notifies the adjacent pico base station 100-3 of the HO request. Then, a HO instruction is notified to the terminal 200 (S151). Also, the pico base station 100-2 transfers an unreached packet or the like to the adjacent pico base station 100-3 (S162).

  In FIG. 17, the processing (S52 to S551) performed by the macro base station 100-1 corresponds to the processing from S51 to S55 and S50 (processing E) in FIG.

  That is, the macro base station 100-1 is a macro base station, does not transmit or receive a HO request (NO in S550), and the loop setting is ON (YES in S551). The macro base station 100-1 ends the processing without performing processing for loop setting.

  On the other hand, the process (S71 to S67) performed by the pico base station 100-2 in FIG. 17 corresponds to the process (process A) from S51 to S67 in FIG.

  That is, the pico base station 100-2 has a pico base station type (NO in S54), transmits a HO request (YES in S650), and loop setting is ON (YES in S651). The loop is released and the loop setting is turned OFF (S66, S67).

  Furthermore, the process (S71 to S70) performed by the adjacent pico base station 100-3 in FIG. 17 corresponds to the process (process D) from S71 to S70 in FIG.

  That is, the adjacent pico base station 100-3 is a pico base station (NO in S54), receives a HO request (NO in S650), and the loop setting is OFF (NO in S651). A loop path is set and the loop setting is turned ON (S68, S69). In this case, the adjacent pico base station 100-3 sets a path with the macro base station 100-1 (S88), and also sets a path with the terminal 200 (S70).

  As described above, a route is set between the terminal 200 and the EPC 500 via the adjacent pico base station 100-3 and the macro base station 100-1, and user data is transferred using the route (S90).

<Example of moving to adjacent pico cell # 2 under the same macro cell with respect to 3.5 3.4>
FIG. 18 shows that the terminal 200 that has moved (handovered) from the macro cell 100-1 to the pico cell 100-2 and further moved to the adjacent pico cell 100-3 in the same macro cell 100-1 is further connected to the neighbor in the same macro cell 100-1. The sequence example in the case of moving to the pico cell 100-4 is shown.

  A route is set from the terminal 200 to the host device via the adjacent pico base station 100-3 and the macro base station 100-1, and user data is transferred using the route (S90).

  Thereafter, the adjacent pico base station 100-3 determines that the terminal 200 is handed over from the adjacent pico base station 100-3 to the adjacent pico base station 100-4 (S51). Then, the adjacent pico base station 100-3 notifies the adjacent pico base station 100-4 of the HO request (S143), notifies the terminal 200 of the HO instruction (S152), and transmits the unreached packet and the like to the adjacent pico base station 100. -4 (S163).

  The processing (S52 to S551) performed by the macro base station 100-1 in FIG. 18 corresponds to the processing from S51 to S55 and S50 (processing E) in FIG.

  Further, the process (S71 to S651) performed by the pico base station 100-2 corresponds to the process (process F) from S51 to S65 and S58 of FIG.

  That is, the pico base station 100-2 has a pico base station type (NO in S54), does not receive a HO request (NO in S650), and the loop setting is OFF (S651). NO). In this case, the pico base station 100-2 ends the series of processing without performing processing for loop setting or the like.

  Furthermore, the process (S51 to S67) performed by the adjacent pico base station 100-3 corresponds to the process (process A) from S51 to S67 of FIG. The adjacent pico base station 100-3 releases the set loop path and turns off the loop setting (S66, S67).

  Furthermore, the process (S71 to S70) performed by the adjacent pico base station 100-4 corresponds to the process (process D) from S71 to S70 of FIG. The adjacent pico base station 100-4 sets a loop path and also sets a path with the terminal 200 (S68, S70). Also, the adjacent pico base station 100-4 sets a path with the macro base station 100-1 (S91).

  As described above, a route is set from the terminal 200 to the host device via the adjacent pico base station 100-4 and the macro base station 100-1, and user data is transferred using the route (S92). .

<Example of a case where a terminal that has moved to an adjacent picocell in 3.6 3.4 moves to a source picocell>
In FIG. 19, the terminal 200 moved (handover) from the macro cell 100-1 to the pico cell 100-2, and moved from the pico cell 100-2 to the adjacent pico cell 100-3 in the same macro cell 100-1, moved to the pico cell 100-2. The sequence example is shown.

  A route is set from the terminal 200 to the EPC 500 via the adjacent pico base station 100-3 and the macro base station 100-1, and user data is transferred using the route (S90).

  Thereafter, the adjacent pico base station 100-3 determines that the terminal 200 is handed over to the pico base station 100-2 (S51). The adjacent pico base station 100-3 notifies the HO request to the pico base station 100-2 (S144), notifies the terminal 200 of the HO instruction (S153), and transfers undelivered packets to the pico base station 100-2. (S164).

  The processing (S52 to S551) performed by the macro base station 100-1 in FIG. 19 corresponds to the processing from S51 to S55 and S50 (processing E) in FIG.

  On the other hand, the process (S71 to S70) performed by the pico base station 100-2 corresponds to the process (process D) from S71 to S70 of FIG. The pico base station 100-2 sets a loop path (S68, S69), and sets a path for the terminal 200 (S70). Also, the pico base station 100-2 sets a path for the macro base station 100-1 (S93).

  Further, the process (S51 to S67) performed by the adjacent pico base station 100-3 corresponds to the process (process A) from S51 to S67 of FIG. The adjacent pico base station 100-3 releases the loop path and turns off the loop path setting (S66, S67).

  As described above, a route is set from the terminal 200 to the host device via the pico base station 100-2 and the macro base station 100-1, and user data is transferred using the route.

[Other embodiments]
FIG. 20 is a diagram illustrating a hardware configuration example of the base station 100. The base station 100 further includes a central processing unit (CPU) 150, a read only memory (ROM) 151, a random access memory (RAM) 152, and a memory 153.

  The CPU 150 reads out the program stored in the ROM 151, loads it into the RAM 152, and executes the loaded program, thereby realizing the functions of the control unit 122, the baseband unit 123, and the timing control unit 125. The CPU 150 corresponds to, for example, the control unit 122, the baseband unit 123, and the timing control unit 125 in the second embodiment.

  Further, the memory 153 stores, for example, an attribute information table 1261 and an attribute change table 1262. The memory 153 corresponds to the memory 126 in the second embodiment, for example.

  Note that a controller such as an MPU (Micro Processing Unit) or an FPGA (Field Programmable Gate Array) may be used instead of the CPU 15.

  In the second embodiment described above, the example of the attribute change table 1262 has been described using the example of FIG. In FIG. 7B, the E-CGI of the pico cell # 1 has been described as “xxx... Xx00. In this E-CGI example, since the Cell ID is “00... 00”, the pico cell # 1 has no sector.

  For example, when there are two sectors in the pico cell # 1, the E-CGI is “xxx... Xxx00... 01” and “xxx. In this case, the two E-CGI's after the attribute change of the pico cell # 1 are, for example, "mmm ... mm00 ... 01" and "mmm ... mm00 ... 02". Further, in this case, the attribute of the pico cell # 2 is changed from “yyy... 00” to “mmm. Even if each pico cell has a sector configuration, the E-CGI ′ after the attribute change includes the eNB ID of the macro base station 100-1 and the Cell ID to which numbers are assigned in order. Accordingly, the E-CGI ′ of each pico cell after the attribute change is changed to a virtual sector in the macro base station 100-1 as in the second embodiment described above, and the macro base station 100-1 Does not have to report the identification information of the pico base station 100-2 to the MME 300 or the like at the time of handover.

  In the embodiment described above, the macro base station 100-1 changes the E-CGI of the pico base station 100-2 because, for example, the terminal 200 changes from the macro base station 100-1 to the pico base station 100-2. It was described as being performed when handing over.

  For example, when the terminal 200 makes a call to the pico base station 100-2 to make a call connection, and then the terminal 200 moves from the pico base station 100-2 to the macro base station 100-1, the E-CGI Changes may be made. In this case, when the macro base station 100-1 receives the HO request from the pico base station 100-2 (for example, S141 in FIG. 15), the attribute of the pico base station 100-2 is described above based on the attribute change table 1262. Change as in the example. Thereby, for example, the macro base station 100-1 does not have to report the identification information of the pico base station 100-2 to the MME 300 or the like at the time of handover.

  The above is summarized as an appendix.

(Appendix 1)
A terminal device that includes a second service area formed by another base station device, forms a first service area that is wider than the second service area, and is wireless with a terminal device that is in the first service area In a base station apparatus that performs communication,
The identification information of the other base station device exchanged between the base station device and another device connected by wire is obtained from the first identification information that identifies the other base station device as the base station device. A base station apparatus comprising: a control unit configured to change to second identification information for identifying each service area formed for each antenna that transmits or receives a radio signal in the base station apparatus.

(Appendix 2)
The first identification information includes identification information for identifying the other base station apparatus, and the second identification information identifies identification information for identifying the base station apparatus and a service area formed by the antenna. The base station apparatus according to appendix 1, wherein the base station apparatus includes identification information.

(Appendix 3)
The base station apparatus according to appendix 1, wherein the first and second identification information are identification information included in E-CGI (E-UTRAN Cell Global Identification).

(Appendix 4)
When the terminal device moves from the base station device to the other base station device, or when the terminal device moves from the other base station device to the base station device, the control unit The base station apparatus according to appendix 1, wherein the identification information is changed.

(Appendix 5)
The control unit changes the identification information of the other base station device from the first identification information to the second identification information when the terminal device moves from the base station device to the other base station device. And setting a route from the terminal device to the other base station device and from the other base station device to the other device via the base station device,
The base station apparatus according to appendix 1, wherein the terminal apparatus and the other apparatus exchange data according to the path.

(Appendix 6)
When the terminal device moves from the base station device to the other base station device, the control unit shifts from the first mode to the second mode, and in the second mode, the other base station Change device identification information from the first identification information to the second identification information, from the terminal device to the other base station device, and from the other base station device via the base station device. Set a route to the other device,
The base station apparatus according to appendix 1, wherein the terminal apparatus and the other apparatus exchange data according to the path.

(Appendix 7)
The control unit generates route information indicating the route, transmits data addressed to the terminal device received from the other device to the other base station device according to the route information, and the other base station device. 8. The base station apparatus according to appendix 6, wherein the data received from the other apparatus is transmitted to the other apparatus.

(Appendix 8)
The base station apparatus according to appendix 7, wherein the control unit transmits the generated path information to the other base station apparatus.

(Appendix 9)
A first base station apparatus forming a first service area;
A second base station apparatus that includes the first service area and forms a second service area that is wider than the first service area;
A terminal device,
In a communication system in which wireless communication is performed between a terminal device located in the first or second service area and the first or second base station device, respectively,
The second base station apparatus is
Identification information of the first base station device exchanged between the second base station device and another device connected by wire, and the first base station device as the second base station device. A control unit for changing from first identification information to be identified to second identification information for identifying each of the service areas formed for each antenna that transmits or receives a radio signal in the second base station apparatus; A communication system characterized by the above.

(Appendix 10)
A terminal device that includes a second service area formed by another base station device, forms a first service area that is wider than the second service area, and is wireless with a terminal device that is in the first service area A control method in a base station apparatus that performs communication,
The control unit is configured to identify identification information of the other base station device exchanged between the base station device and another device wired to the base station device, and to identify the other base station device from the base station device. The control method is characterized in that the identification information is changed to second identification information for identifying each of the service areas formed for each antenna that transmits or receives a radio signal in the base station apparatus.

(Appendix 11)
A terminal device that includes a second service area formed by another base station device, forms a first service area that is wider than the second service area, and is wireless with a terminal device that is in the first service area In a base station apparatus that performs communication,
The identification information of the other base station device exchanged between the base station device and another device connected by wire is obtained from the first identification information that identifies the other base station device as the base station device. A base station apparatus comprising a controller for changing to second identification information for identifying each service area formed for each antenna that transmits or receives a radio signal in the base station apparatus.

10: Communication system 100: Base station apparatus 100-1: Macro base station (macro cell)
100-2: Pico base station (picocell)
100-M: Service area (macro cell)
100-P: Service area (picocell)
110: Radio unit 120: Control / baseband unit 121: Interface unit 122: Control unit 126: Memory 1261: Attribute information table 1262: Attribute change table 200: Terminal device 300: MME 400: S-GW
500: EPC

Claims (5)

A terminal device that includes a second service area formed by another base station device, forms a first service area that is wider than the second service area, and is wireless with a terminal device that is in the first service area In a base station apparatus that performs communication,
The identification information of the other base station device exchanged between the base station device and another device connected by wire is obtained from the first identification information that identifies the other base station device as the base station device. A base station apparatus comprising: a control unit configured to change to second identification information for identifying each service area formed for each antenna that transmits or receives a radio signal in the base station apparatus.   The first identification information includes identification information for identifying the other base station apparatus, and the second identification information identifies identification information for identifying the base station apparatus and a service area formed by the antenna. The base station apparatus according to claim 1, further comprising identification information.   When the terminal device moves from the base station device to the other base station device, or when the terminal device moves from the other base station device to the base station device, the control unit The base station apparatus according to claim 1, wherein a change to identification information is performed. When the terminal device moves from the base station device to the other base station device, the control unit shifts from the first mode to the second mode, and in the second mode, the other base station Change device identification information from the first identification information to the second identification information, from the terminal device to the other base station device, and from the other base station device via the base station device. Set a route to the other device,
The base station apparatus according to claim 1, wherein the terminal apparatus and the other apparatus exchange data according to the path.   The control unit generates route information indicating the route, transmits data addressed to the terminal device received from the other device to the other base station device according to the route information, and the other base station device. The base station apparatus according to claim 4, wherein the data received from the base station is transmitted to the other apparatus.

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