Communication evaluation system and communication evaluation method

Abstract

To provide a communication evaluation system and a communication evaluation method that can optimize communication between a base station and a terminal.SOLUTION: A communication evaluation system includes a virtual building construction unit that virtually constructs a base station and a terminal in a building, a radio wave propagation characteristic calculation unit that calculates radio wave propagation characteristics between the base station and the terminal in the building, a received power calculation unit that calculates received power of communication performed between the base station and the terminal from the radio wave propagation characteristics calculated by the radio wave propagation characteristics calculation unit, and a communication simulation unit that causes the radio wave propagation characteristic calculation unit to calculate the radio wave propagation characteristics, which is triggered by the occurrence of communication between the base station and the terminal in the virtually constructed building, causes the received power calculation unit to calculate received power on the basis of the calculated radio wave propagation characteristics, and simulates the state of communication between the base station and the terminal on the basis of the calculated received power.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication evaluation system and a communication evaluation method. [Background technology]

[0002] Conventionally, in communications between a plurality of terminals and a plurality of base stations, there has been a demand for optimizing communications between the terminals and the base stations while maintaining the availability of communications between them. Patent Document 1 discloses a mobile communications system that, when it is determined that communications at a wireless base station are congested based on the traffic volume of the wireless base station, has a wireless terminal making a new connection request select which of a plurality of base stations to connect to, thereby ensuring an appropriate traffic volume. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-085020 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned conventional technology controls communication between a base station and a terminal based solely on the traffic volume between the base station and the terminal, but this configuration has the problem of being unable to respond to changes in the radio wave propagation environment due to the characteristics of individual structures such as equipment and walls within a building, or changes in the state of the terminal, such as movement.

[0005] The present invention has been made in consideration of such problems, and aims to provide a communication evaluation system and a communication evaluation method that can optimize communication conducted by a terminal by evaluating communication between a base station and a terminal in consideration of the radio wave propagation characteristics between them. [Means for solving the problem]

[0006] According to one aspect of the present invention, the system includes a virtual building construction unit that virtually constructs a base station and a terminal within a building; a radio wave propagation characteristic calculation unit that calculates radio wave propagation characteristics between the base station and the terminal within the building; a received power calculation unit that calculates the received power of communication between the base station and the terminal from the radio wave propagation characteristics calculated by the radio wave propagation characteristic calculation unit; and a communication simulation unit that, in response to the occurrence of communication between the base station and the terminal within the virtually constructed building, causes the radio wave propagation characteristic calculation unit to calculate the radio wave propagation characteristics, causes the received power calculation unit to calculate the received power based on the calculated radio wave propagation characteristics, and simulates the state of communication between the base station and the terminal based on the calculated received power. [Effects of the Invention]

[0007] According to the present invention, it is possible to evaluate the state of wireless communication occurring between a base station and a terminal in a virtually constructed building while taking into account radio wave propagation characteristics, thereby making it possible to optimize, for example, the location and number of base stations in communication between terminals in an actual building. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a functional block diagram of a communication evaluation system according to an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram of a computer that executes the processing of the communication evaluation system. [Figure 3] FIG. 1 is an explanatory diagram showing the arrangement of base stations and terminals in a virtual building. [Figure 4] FIG. 10 is a sequence diagram showing a processing flow of the communication evaluation system. [Figure 5] FIG. 10 is an explanatory diagram showing specific evaluation contents in the communication evaluation system. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1 shows a functional block diagram of a communication evaluation system 1 according to this embodiment.

[0011] The communication evaluation system 1 of this embodiment evaluates communications between multiple base stations and multiple terminals (mobile terminals) within a building. Specifically, the communication evaluation system 1 simulates communications between base stations and terminals within a virtually constructed building as time-series changes, and evaluates the communication status between these base stations and terminals. This makes it possible to optimize, for example, the location and number of base stations in communications between base stations and terminals within an actual building.

[0012] FIG. 1 shows a functional block diagram of a communication evaluation system 1 according to this embodiment.

[0013] The communication evaluation system 1 includes a virtual building interior construction unit 10, a radio wave propagation characteristic calculation unit 20, a received power calculation unit 30, a communication simulation unit 40, and a communication evaluation unit 50.

[0014] The virtual building interior construction unit 10 constructs base stations and terminals provided in an actual building as a virtual space, and provides the base stations and terminals present in the virtual space.

[0015] The radio wave propagation characteristic calculation unit 20 calculates the radio wave propagation characteristics between the base station and the terminal in the virtually constructed building.

[0016] Based on the radio wave propagation characteristics calculated by the radio wave propagation characteristics calculation unit 20, the received power calculation unit 30 calculates the received power of wireless communication performed between the base station and the terminal in the virtually constructed building.

[0017] The communication simulator 40 simulates the state transition of wireless communication between a base station and a terminal in a virtually constructed building by referring to the received power calculated by the received power calculator 30.

[0018] Based on the results of the simulation performed by the communication simulation unit 40, the communication evaluation unit 50 evaluates the communication performed by the terminal, for example, communication between terminals, or communication between a terminal and a device outside the building via a backhaul (wired or wireless) such as a WAN or LAN outside the building.

[0019] FIG. 2 is an explanatory diagram of a computer 100 that executes the processing of the communication evaluation system 1 according to the embodiment of the present invention.

[0020] The communication evaluation system 1 is implemented on a computer 100. The computer 100 includes a CPU 110, a storage unit 120, an interface 130, and an internal bus 140.

[0021] The CPU 110 reads and executes a program stored in the storage unit 120. The CPU 110 executes the program to realize various functions described below.

[0022] The storage unit 120 stores programs executed by the CPU 110. The storage unit 120 is also used as a temporary work area for the programs executed by the CPU 110. The storage unit 120 includes a nonvolatile memory such as a ROM, a volatile memory such as a RAM, or a fixed disk such as an HDD or SSD.

[0023] The interface 130 includes a display device such as a display, and input devices such as a keyboard and a mouse, receives information entered by the administrator, and displays the results on the display. The interface 130 also includes a network interface such as a LAN, and is configured to be able to send and receive information to and from other computers.

[0024] The internal bus 140 interconnects the CPU 110, the storage unit 120, and the interface 130.

[0025] In this embodiment, the communication evaluation system 1 is configured by a single computer 100 executing a program as shown in Fig. 2, but is not limited to this. The communication evaluation system 1 may be configured by multiple computers 100 each performing different functions and transmitting and receiving information to and from each other via a network interface.

[0026] FIG. 3 is an explanatory diagram of an example of a virtual building 500 constructed in the communication evaluation system 1 of this embodiment.

[0027] In an actual building, there are various structures and objects such as walls, floors, and fixtures. These structures and objects each have a position, a unique shape (height, width, depth), and physical properties (dielectric constant, conductivity, etc.). In the communication evaluation system 1, the administrator inputs the positions, shapes, and physical properties of the structures and objects as numerical values to the virtual building interior construction unit 10. Furthermore, the positions and types of base stations and terminals to be placed in the building are input as numerical values. In this way, a virtual building is constructed. This information is stored in the communication evaluation system 1.

[0028] The constructed virtual building is used by the radio wave propagation characteristic calculation unit 20 when calculating the radio wave propagation characteristics between the base station and the terminal.

[0029] FIG. 3 shows an example in which a virtual building 500 is equipped with a network device NT1, a plurality of base stations AP (AP1 to AP5), a plurality of terminals STA (STA1 to STA5), and a plurality of fixtures (501 to 506).

[0030] The network device NT1 functions as a router or gateway, and manages communications between the terminals (STA1 to STA5) or communications between the terminals STA and an external device 700 via a network 600 (LAN or WAN) outside the virtual building 500. The external device 700 is configured by, for example, a host such as a Web server or an application server, or a terminal similar to the terminal STA.

[0031] The base station AP is configured to be able to wirelessly communicate with the terminal STA in accordance with the wireless LAN standard, for example, IEEE802.11.

[0032] The terminal STA is configured to perform wireless communication with the base station AP, thereby communicating with other terminal STAs within the virtual building 500 or with an external device 700 outside the virtual building 500. STA1, terminal STA2, and terminal STA3 are mobile terminals (for example, portable notebook computers or mobile devices), and terminal STA4 and terminal STA5 are configured as fixed terminals (for example, personal computers or IoT devices).

[0033] In the virtual building 500 constructed in this way, for example, consider a case where a terminal STA1 communicates with an external device 700 via wireless communication with a base station AP5. In this wireless communication, radio waves propagate between the base station AP5 and the terminal STA1 in a direct manner, and radio waves reflected and diffracted by walls, floors, furniture 505, and furniture 506 propagate between them.

[0034] These radio waves have different directions and arrival times, and therefore affect the propagation state of the radio waves between the base station AP5 and the terminal STA1.

[0035] Therefore, the radio wave propagation characteristic calculation unit 20 calculates the radio wave propagation characteristics propagating between the two points, the base station AP and the terminal STA. The radio wave propagation characteristics are calculated using, for example, the ray tracing method. The ray tracing method traces all of the direct waves, reflected waves, transmitted waves, and diffracted waves of the radio waves that reach the receiver from the transmitter, and then combines these to calculate the propagation loss, delay time, emission direction, and arrival direction of the radio waves.

[0036] The radio wave propagation characteristics calculated by the radio wave propagation characteristic calculation unit 20 are passed to the received power calculation unit 30. The received power calculation unit 30 calculates the characteristics of communication data to be superimposed on radio waves in the radio wave propagation characteristics calculated by the radio wave propagation characteristic calculation unit 20.

[0037] More specifically, the transmission radio wave modulated and transmitted by the transmitter is received by the receiver in accordance with the calculated radio wave propagation characteristics. The received power calculation unit 30 calculates the received power of the radio wave received by the receiver, and also calculates the SINR (ratio of interference waves and noise waves to the signal) of the received radio wave and the BER (error rate) by performing error correction on the demodulated data. In this way, the received power calculation unit 30 calculates the received power and error rate of the wireless communication transmitted from the transmitter to the receiver. For example, MATLAB (registered trademark) is used for the calculations in the received power calculation unit 30.

[0038] The communication simulator 40 simulates communication between a sender and a receiver based on a predetermined communication protocol, based on the calculated reception power and error rate.

[0039] As a specific example, a case will be described in which a terminal STA communicates with an external device 700 based on the HTTP protocol via wireless communication with a base station AP. First, a wireless communication line is established between the base station AP and the terminal STA. The terminal STA generates a request in the application layer according to the HTTP protocol for the external device 700 in accordance with a predetermined procedure, and transmits the request to the external device 700 via the wireless line to the base station AP established in the MAC layer. The external device 700 responds to the request and transfers the response to the request to the terminal STA via the wireless line established by the base station AP. The terminal STA, having received the response, further transmits a request via the base station AP. Communication including wireless communication is performed by repeating such communication.

[0040] The communication simulator 40 checks the state of wireless communication between the base station AP and the terminal STA using a statistical method, applying the received power and error rate calculated by the received power calculator 30. More specifically, the communication simulator 40 checks whether the wireless communication satisfies the response speed and transfer rate required for the communication protocol performed via the wireless communication, using the calculated received power and error rate. Note that the communication simulator 40 may check the state of wireless communication using only the received power calculated by the received power calculator 30.

[0041] If the communication simulator 40 determines that the required transfer rate or the quality of the application service provided by the HTTP protocol (for example, video resolution or audio delay) is not satisfied, it examines whether a base station AP other than the currently communicating base station AP can perform more suitable wireless communication. That is, it searches based on the calculation results of the radio wave propagation characteristic calculator 20 and the received power calculator 30 whether better received power or error rate can be obtained when wireless communication is performed with a base station AP other than the currently communicating base station AP, and examines whether switching to a more suitable base station AP is possible.

[0042] Furthermore, for example, when base station AP5 and terminal STA1 are performing wireless communication, it is also possible to simulate the case where terminal STA1 moves to position A in Fig. 3. When terminal STA1 reaches position A, the communication simulator 40 considers switching the wireless communication between base station AP5 and terminal STA1 to another base station AP with better performance, if necessary, based on the calculation results of the radio wave propagation characteristic calculator 20 and the received power calculator 30.

[0043] FIG. 4 is a sequence diagram showing the flow of processing performed in the communication evaluation system 1 of this embodiment.

[0044] FIG. 4 shows an example in which the communication simulator 40 simulates three communications: wireless communication #1, wireless communication #2, and wireless communication #3.

[0045] When an event occurs in wireless communication #1 and wireless communication starts, the communication simulator 40 first causes the radio wave propagation characteristic calculator 20 to calculate the radio wave propagation characteristics between two points in wireless communication #1 (for example, base station AP1 and terminal STA5). Next, the communication simulator 40 uses the calculated radio wave propagation characteristics to cause the received power calculator 30 to calculate the received power and error rate between the two points in wireless communication #1. The communication simulator 40 receives the calculation results and checks the state of wireless communication #1.

[0046] Similarly, when an event occurs in wireless communication #2 and wireless communication starts, the communication simulator 40 causes the radio wave propagation characteristic calculator 20 to calculate the radio wave propagation characteristics between two points in wireless communication #2 (for example, terminal STA5 and base station AP1), and causes the received power calculator 30 to calculate the received power and error rate between the two points in wireless communication #2 using the calculated radio wave propagation characteristics. The communication simulator 40 receives the calculation results and checks the state of wireless communication #2.

[0047] The events include the start of wireless communication between the base station AP and the terminal STA, the end of wireless communication, a change in the communication state, power-on, reboot, etc. When the communication simulator 40 detects the occurrence of such an event, it repeats the above-described process and can check the states of multiple wireless communications occurring simultaneously.

[0048] FIG. 5 is an explanatory diagram showing specific simulation contents in the communication evaluation system 1 of this embodiment.

[0049] The example shown in FIG. 5 is an example in which the communication simulator 40 specifically performs three communications: wireless communication #1, wireless communication #2, and wireless communication #3.

[0050] When wireless communication #1 is initiated between base station AP1 and terminal STA5, the communication simulator 40 simulates the establishment of a connection at the physical layer and communication at the MAC layer (data link layer) based on a communication protocol (e.g., video communication based on H.323 with an external device 700) performed via the wireless communication. Furthermore, since the destination of this wireless communication #1 is wireless communication #2, the simulator 40 also simultaneously simulates the establishment of wireless communication #2 in response to the establishment of wireless communication #1. The communication simulator 40 checks whether the response speed and transfer rate based on the communication protocol performed via the wireless communication are sufficient for wireless communication #1 and wireless communication #2.

[0051] Here, the communication simulator 40 simulates the start of wireless communication #3. Wireless communication #3 is a communication protocol (e.g., voice communication based on VoIP with an external device 700) via wireless communication performed between base station AP1 and terminal STA3. In this communication, terminal STA3 connects to the same base station AP1 as in wireless communication #1 and wireless communication #2. Therefore, the communication simulator 40 confirms that the response speed and transfer rate based on the communication protocol performed via this wireless communication are insufficient due to interference with wireless communication #1 and wireless communication #2. Based on this, the communication simulator 40 switches (hands over) wireless communication #3 to another base station (base station AP3). As a result, wireless communication #3 is switched to be performed between base station AP3 and terminal STA3, and it can be confirmed that the response speed and transfer rate based on the protocol of the communication performed via this wireless communication are now sufficient.

[0052] In the above example, the communication simulator 40 performs handover to another base station AP when the response speed or transfer rate based on the communication protocol performed via the wireless communication is insufficient, but this is not limiting, and the communication simulator 40 may inquire of the administrator as to which base station AP to handover to, or may allow communication between the base station AP1 and the terminal STA3 to continue at a lower transfer rate. These arrangements are set in advance in the communication simulator 40 by the administrator.

[0053] Based on the results of the simulation of wireless communication between the base station AP and the terminal STA in a virtual building by the communication simulator 40, the communication evaluation unit 50 evaluates the communication between the terminal STA and the external device 700 via the wireless communication between the base station AP and the terminal STA. By considering the results of the simulation performed by the communication simulator 40, the communication evaluation unit 50 can evaluate whether the response speed and transfer rate based on the protocol of the communication performed between the terminal STA and the external device 700 are sufficient. Based on the evaluation performed by the communication evaluation unit 50, it is possible to know in advance the location, number, direction, and arrangement of the base station APs in an actual building. Furthermore, if the evaluation results in a situation where it is determined that there is little communication with the base station AP, the power of the base station AP can be turned off to save power in the building.

[0054] The embodiment of the present invention described above includes a virtual building construction unit 10 that virtually constructs a base station AP and a terminal STA within a building; a radio wave propagation characteristic calculation unit 20 that calculates radio wave propagation characteristics between the base station AP and the terminal STA within the virtually constructed building; a received power calculation unit 30 that calculates the received power of wireless communication between the base station AP and the terminal STA from the radio wave propagation characteristics calculated by the radio wave propagation characteristic calculation unit 20; and a communication simulation unit 40 that, when communication between the base station AP and the terminal STA within the virtually constructed building occurs, causes the radio wave propagation characteristic calculation unit 20 to calculate the radio wave propagation characteristics, causes the received power calculation unit 30 to calculate the received power based on the calculated radio wave propagation characteristics, and simulates the state transition of communication between the base station AP and the terminal STA based on the calculated received power.

[0055] With this configuration, it is possible to evaluate the state of wireless communication by simulating wireless communication occurring between a base station AP and a terminal STA in a virtually constructed building, taking into consideration the radio wave propagation characteristics in the virtually constructed building. This makes it possible to optimize, for example, the location and number of base stations AP in wireless communication between a base station AP and a terminal STA in an actual building.

[0056] Furthermore, in this embodiment, the radio wave propagation characteristic calculation unit 20 calculates the radio wave propagation characteristics based on the direct waves, reflected waves, and diffracted waves propagating between the base station AP and the terminal STA within a virtually constructed building, and therefore, the radio wave propagation characteristics can be calculated taking into account the walls, floors, and structures located within the virtual building.

[0057] In addition, in this embodiment, the received power calculation unit 30 can calculate the received power of the wireless communication performed between the base station AP and the terminal STA by performing modulation, demodulation, and error correction of the wireless communication performed between the base station AP and the terminal STA based on the radio wave propagation characteristics calculated by the radio wave propagation characteristic calculation unit 20.

[0058] Furthermore, in this embodiment, when communication occurs between the base station AP and the terminal STA, the communication simulation unit 40 evaluates whether the response speed and transfer rate of the wireless communication between the base station AP and the terminal STA are sufficient based on the calculated received power, thereby making it possible to confirm that the wireless communication between the base station AP and the terminal STA is being carried out satisfactorily.

[0059] Furthermore, in this embodiment, a plurality of base stations APs and a plurality of terminal STAs are arranged in a virtually constructed building, and when the communication simulation unit 40 determines that the response speed and transfer rate of wireless communication between any one of the base stations APs and any one of the terminal STAs is insufficient, it switches the base station AP to another base station AP, thereby making it possible to simulate state transitions when wireless communication between the base station AP and the terminal STA is insufficient.

[0060] Although the embodiments of the present invention have been described above, the above embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0061] 1. Communication evaluation system 10 Virtual Building Construction Department 20 Radio wave propagation characteristic calculation section 30 Received power calculation unit 40 Communication Simulation Section 50 Communication Evaluation Department 100 computers 700 External device AP base station STA terminal

Claims

1. a virtual building construction unit that virtually constructs a base station and a terminal in a building; a radio wave propagation characteristic calculation unit that calculates radio wave propagation characteristics between the base station and the terminal in the building; a reception power calculation unit that calculates reception power of wireless communication performed between the base station and the terminal based on the radio wave propagation characteristics calculated by the radio wave propagation characteristics calculation unit; a communication simulation unit that, when wireless communication between the base station and the terminal in the building occurs, causes the radio wave propagation characteristic calculation unit to calculate the radio wave propagation characteristics, causes the received power calculation unit to calculate the received power based on the calculated radio wave propagation characteristics, and simulates communication between the base station and the terminal based on the calculated received power, Communication evaluation system.

2. 2. The communication evaluation system according to claim 1, Further, a communication evaluation unit is provided that evaluates communication between the terminal and another terminal or a virtually constructed external device outside the building based on a simulation result performed by the communication simulation unit. Communication evaluation system.

3. 2. The communication evaluation system according to claim 1, the radio wave propagation characteristic calculation unit calculates the radio wave propagation characteristics based on a direct wave, a reflected wave, and a diffracted wave propagating between the base station and the terminal within the building; Communication evaluation system.

4. 2. The communication evaluation system according to claim 1, the received power calculation unit calculates the received power of the wireless communication performed between the base station and the terminal by performing modulation, demodulation, and error correction of the wireless communication performed between the base station and the terminal based on the radio wave propagation characteristics calculated by the radio wave propagation characteristic calculation unit. Communication evaluation system.

5. 2. The communication evaluation system according to claim 1, The communication simulation unit When communication occurs between the base station and the terminal, evaluate whether or not a response speed and a transfer rate of the wireless communication between the base station and the terminal are sufficient based on the calculated received power. Communication evaluation system.

6. 6. The communication evaluation system according to claim 5, a plurality of the base stations and a plurality of the terminals are arranged in the building; when the communication simulation unit determines that the response speed and the transfer rate of the wireless communication between any one of the base stations and any one of the terminals are insufficient, the communication simulation unit switches the base station to another of the base stations; Communication evaluation system.

7. Virtually constructing base stations and terminals within a building, Calculating radio wave propagation characteristics between the base station and the terminal in response to occurrence of wireless communication between the base station and the terminal in the building; calculating a received power of the wireless communication performed between the base station and the terminal from the calculated radio wave propagation characteristics; simulating communication between the base station and the terminal based on the calculated received power; Communication evaluation methods.

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