JP5224247B2 - Station design support apparatus and computer program - Google Patents

Description

  The present invention relates to a station location design support apparatus and a computer program.

  Conventionally, in a cellular mobile communication system in which a plurality of base stations are arranged and a continuous communication service area is constructed by the communication area (cell) of each base station, as a technique for supporting base station station design, for example, Patent Documents 1 and 2 and Non-Patent Document 1 are known.

JP 2001-285923 A JP-T-2004-513537

Ericsson, “Planet EV” [searched August 21, 2008], Internet <URL: http://www.ericsson.com/solutions/tems/network_plan/planetev.shtml>

  However, in the conventional technique described above, base station cooperation in which a plurality of base stations cooperate to communicate with a mobile station by using a multiple input multiple output (MIMO) technique using a plurality of antennas. Since communication is not taken into consideration, sufficient support cannot be provided for station design that considers base station cooperative communication.

  The present invention has been made in view of such circumstances, and its object is to provide a placement design support device that improves support capability for placement design considering base station cooperative communication in a cellular mobile communication system, and To provide a computer program.

  In order to solve the above-described problem, a station placement design support apparatus according to the present invention includes an input unit that inputs a station placement design condition, base station arrangement in a station placement design target area specified by the station placement design condition, and Based on the radio wave propagation environment of each base station, a simulation model generation unit that determines an affiliated base station, a collaborative base station and a non-cooperating base station for each section of the station design target area, and each section of the station design target area In addition, for each section of the station design target area, a communication method determination unit that determines a communication method of base station cooperative communication based on an assumed radio wave state between the affiliated base station, a collaborative base station, and a non-cooperative base station, A radio characteristic calculation unit that calculates an assumed radio characteristic based on a communication method of base station cooperative communication, and an output unit that outputs the assumed radio characteristic of each section of the station design target area are provided.

  In the station placement design support apparatus according to the present invention, the communication method determination unit is configured to assume an assumed reception power of a radio wave from an affiliated base station and a radio wave from a cooperable base station in each section of the station placement design target area. LAR calculation means for calculating the ratio (LAR) to the total received power, the assumed received power of the radio wave from the affiliated base station, and the assumed total received radio wave from the non-cooperating base station in each section of the station design target area LFNR calculating means for calculating a ratio (LFNR) between power and assumed noise power, and the station location design support apparatus is information on a set of communication methods of LAR, LFNR, frequency utilization efficiency, and base station cooperative communication Is further provided with a base station cooperative communication characteristic database for storing.

  In the station placement design support apparatus according to the present invention, for a plurality of combinations of base station arrangements specified in the station placement design conditions, the number of partitions satisfying the assumed radio characteristics criterion in the station placement design target area is maximized. An optimization unit that performs optimization processing is further provided.

  The computer program according to the present invention is based on the step of inputting the station design conditions, the base station arrangement in the station design target area specified by the station design conditions, and the radio wave propagation environment of each base station. The step of determining the belonging base station, collaborative base station and non-cooperating base station for each section of the design target area, and the belonging base station, cooperating base station and non-cooperating base station for each section of the station design target area A step of determining a communication method of base station cooperation communication based on an assumed radio wave state between, a step of calculating an assumed radio characteristic based on a communication method of base station cooperation communication for each section of the station design target area, A computer program for causing a computer to execute an assumed wireless characteristic of each section of the station design target area.

  In the computer program according to the present invention, in the step of determining the communication method, the assumed received power of the radio wave from the affiliated base station and the assumed total radio wave from the cooperable base station in each section of the station design target area. Calculate the ratio (LAR) to the received power (LAR), and the estimated received power of the radio wave from the affiliated base station and the assumed total received power and the assumed noise power of the non-cooperating base station in each section of the station design target area Base station cooperative communication with a maximum frequency use efficiency corresponding to LAR and LFNR based on information on a set of communication methods of LAR, LFNR, frequency use efficiency, and base station cooperative communication The communication method is selected.

In the computer program according to the present invention, an optimization process for maximizing the number of partitions satisfying a criterion of assumed radio characteristics in an installation target design area for a plurality of combinations of base station arrangements specified by the installation design conditions It is a computer program for making a computer perform the step which performs this.
Thereby, the above-described station location design support apparatus can be realized using a computer.

  According to the present invention, in the cellular mobile communication system, it is possible to improve the support capability for the station design considering the base station cooperative communication.

It is a block diagram which shows the structure of the station location design assistance apparatus 1 which concerns on one Embodiment of this invention. It is an example of the division of the in-station design target area. It is an example of an affiliated base station, a collaborative base station, and a non-cooperative base station.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a station placement design support apparatus 1 according to an embodiment of the present invention. In FIG. 1, the station location design support apparatus 1 includes an input unit 2, an output unit 3, a database unit 4, a simulation model generation unit 5, a communication method determination unit 6, a wireless characteristic calculation unit 7, a simulation data storage unit 8, and an optimization. Part 9. The database unit 4 includes a map database 21, a building database 22, and a base station cooperation communication characteristic database 23.

[Map database, building database]
The map database 21 stores map data of the service area of the cellular mobile communication system. The building database 22 stores information on buildings in the service area of the cellular mobile communication system.
Note that the map database 21 and the building database 22 are not necessary when the necessary map data and building information are included in the station location design conditions and input from the input unit 2 described later.

[Input section]
The input unit 2 inputs station location design conditions. The station design conditions specify base station arrangement within the station design target area and the radio wave propagation environment of each base station. As the station design target area, an area that is a target for station design is selected in map data of a service area of the cellular mobile communication system (hereinafter simply referred to as map data). As the base station arrangement, a place where the base station is installed is selected in the map data of the service area of the cellular mobile communication system. The radio wave propagation environment represents a propagation state of radio waves transmitted from the base station. Examples of the radio wave propagation environment include base station information such as the number of antennas of the base station, antenna height, directivity pattern and tilt angle, obstacle information such as building arrangement and building height, path loss model data, and the like.

[Simulation data storage unit]
The simulation data storage unit 8 stores data of the simulation model generation unit 5, the communication method determination unit 6, the wireless characteristic calculation unit 7, and the optimization unit 9. The simulation data storage unit 8 appropriately reads data from the simulation model generation unit 5, the communication method determination unit 6, the wireless characteristic calculation unit 7, the optimization unit 9, and the output unit 3.

[Simulation model generator]
Based on the base station arrangement in the station design target area and the radio wave propagation environment of each base station specified by the station design conditions, the simulation model generation unit 5 A base station that can cooperate and a non-cooperative base station are determined. Hereinafter, this simulation model generation method will be described.

  First, the station design target area is divided on the map data. FIG. 2 shows an example of the area design target area segmentation. Hereinafter, the section of the station design target area is referred to as STP (Service Test Point). The size of the STP is included in the station location design conditions. Hereinafter, a process for one STP will be described, but the process is performed for all STPs.

  Next, an assumed received signal strength indicator (RSSI) from each neighboring base station at the center position of the STP is calculated. The assumed RSSI from a certain base station can be calculated based on the radio wave propagation environment of the base station.

  Next, based on the assumed RSSI of each base station, an affiliated base station, a collaborative base station, and a non-cooperative base station in the STP are determined. Only one base station having the maximum assumed RSSI is selected as the affiliated base station. The affiliated base station is a base station that is a main connection partner of the STP. All base stations having an assumed RSSI whose difference from the assumed RSSI of the affiliated base station is greater than or equal to a reference value are selected as base stations capable of cooperating. Therefore, there may be a plurality of cooperable base stations. The collaborative base station is a base station that can communicate with the STP in cooperation with the affiliated base station. For non-cooperating base stations, all base stations having an assumed RSSI whose difference from the assumed RSSI of the belonging base station is less than the reference value are selected. Therefore, there may be a plurality of non-cooperating base stations. A non-cooperating base station is a base station that does not even communicate with the STP in cooperation with the affiliated base station. However, a base station having an assumed RSSI that is so small that the difference from the assumed RSSI of the affiliated base station is so small that the influence of interference on the STP can be ignored may not be included in the non-cooperating base station. Thereby, the amount of calculation can be reduced without causing accuracy degradation.

[Communication method decision unit, base station cooperation communication characteristics database]
The communication method determination unit 6 determines a communication method for base station cooperative communication for each STP based on an assumed radio wave state among the affiliated base station, the collaborative base station, and the non-cooperative base station. Hereinafter, this communication method determination method will be described. Note that the communication method of base station cooperation communication includes whether or not a plurality of base stations cooperate to communicate with a mobile station.

First, the ratio (LAR) between the assumed received power of radio waves from the affiliated base station and the assumed total received power of radio waves from cooperable base stations at the center position of the STP is calculated. LAR is expressed by the following equation.
LAR = L / A
Where L is the assumed received power of radio waves from the base station to which it belongs. A is an assumed total received power of radio waves from a base station capable of cooperation.

In the example of FIG. 3, there are a base station (BS0) and two base stations (BSA1, BSA2) that can be associated with a certain STP. The assumed received power (L) of the affiliated base station (BS0), the assumed received power (A ₁ ) of the cooperable base station (BSA1), and the assumed received power (A ₂ ) of the cooperable base station (BSA2). Thereby, the assumed total received power (A) of radio waves from the cooperable base station is “assumed received power (A ₁ ) + assumed received power (A ₂ )”. Therefore,
LAR = L / (A ₁ + A ₂ )
It is.

Next, the ratio (LFNR) between the assumed received power of the radio wave from the base station to which the STP is located and the assumed total received power and assumed noise power of the radio wave from the non-cooperating base station is calculated. LFNR is represented by the following equation.
LFNR = L / (F + N)
Where L is the assumed received power of radio waves from the base station to which it belongs. F is the assumed total received power of radio waves from non-cooperating base stations. N is the assumed noise power.

In the example of FIG. 3, for a certain STP, there are an affiliated base station (BS0) and two non-cooperating base stations (BSF1, BSF2). The assumed received power (L) of the affiliated base station (BS0), the assumed received power (F ₁ ) of the non-cooperating base station (BSF1), and the assumed received power (F ₂ ) of the non-cooperating base station (BSF2). Thereby, the assumed total received power (F) of radio waves from the non-cooperating base station is “assumed received power (F ₁ ) + assumed received power (F ₂ )”. Therefore,
LFNR = L / (F ₁ + F ₂ + N)
It is.

  Next, based on information on a set of communication methods of LAR, LFNR, frequency utilization efficiency, and base station cooperation communication, a communication method of base station cooperation communication corresponding to LAR and LFNR with the maximum frequency utilization efficiency is selected. At this time, the base station cooperation communication characteristic database 23 is used.

  The base station cooperation communication characteristic database 23 stores information on a set of communication methods of LAR, LFNR, frequency utilization efficiency, and base station cooperation communication. The information stored in the base station cooperative communication characteristic database 23 is a communication method of base station cooperative communication corresponding to a certain LAR and a certain LFNR pair and the frequency utilization efficiency at that time, for each pair of LAR and LFNR. Therefore, if LAR and LFNR are known, the communication method and frequency utilization efficiency of base station cooperative communication corresponding to the set of LAR and LFNR can be acquired from the base station cooperative communication characteristic database 23. As a result, the base station cooperation communication characteristic database 23 is referred to, and the base station cooperation communication with the maximum frequency use efficiency is selected from the communication methods and frequency use efficiencies of all base station cooperation communication corresponding to the LAR and LFNR pairs. The communication method of base station cooperation communication which is the search result is employed. At this time, the corresponding frequency use efficiency is stored in the simulation data storage unit 8 together with the communication method of the base station cooperative communication as the search result.

As a communication method of base station cooperation communication,
(1) One mobile station and one base station perform one-to-one communication (referred to as “single site connection”);
(2) One mobile station and a plurality of base stations that perform one-to-many communication (referred to as “multi-site connection”);
There is.
Further, a combination of the number of transmission antennas and the number of reception antennas is set as a setting in MIMO. For example, one transmitting antenna and one receiving antenna (1 × 1 MIMO (this corresponds to SISO (Single Input Single Output))), two transmitting antennas and two receiving antennas (2 × 2 MIMO), a transmitting antenna There are four and four receiving antennas (4 × 4 MIMO), six transmitting antennas and six receiving antennas (6 × 6 MIMO), and the like.

[Wireless characteristics calculator]
The radio characteristic calculation unit 7 calculates the assumed radio characteristic for each STP based on the communication method of base station cooperative communication. Examples of the assumed wireless characteristics calculated here include carrier to interference and noise power ratio (CINR), electric field strength, and throughput. Note that the assumed wireless characteristics include frequency utilization efficiency, but the frequency utilization efficiency is stored in the simulation data storage unit 8 by the communication method determination unit 6 and therefore need not be calculated here.

  In calculating CINR, in each STP, a base station that performs base station cooperative communication is set as a desired base station, and CINR is calculated for each set of the desired base station and other base stations.

  In the calculation of throughput, the throughput is calculated based on the frequency bandwidth included in the station location design conditions. Further, the station design condition may include the density of active mobile stations, and the expected value of throughput obtained in each STP may be obtained in consideration of the distribution of mobile stations.

[Output section]
The output unit 3 outputs the assumed radio characteristics of each STP. The output unit 3 generates output data based on the data stored in the simulation data storage unit 8. Specifically, in order to present information such as information on the affiliated base station, cooperable base station and non-cooperating base station, communication method of base station cooperative communication, frequency utilization efficiency, CINR, electric field strength, and throughput in each STP Output data is generated. For example, output data for displaying such information on a map is generated. The frequency use efficiency, CINR, electric field strength, and throughput may be expressed by color coding.

[Optimization section]
The optimization unit 9 performs an optimization process for maximizing the number of STPs that satisfy the criterion of the assumed radio characteristics in the station placement design target area for a plurality of combinations of base station arrangements specified by the station placement design conditions. For example, among the plurality of combinations of base station arrangements, a combination that maximizes the number of STPs that satisfy the frequency utilization efficiency reference value is obtained as the entire station-designed area. Furthermore, a combination that maximizes the efficiency of base station installation costs may be obtained. As the optimization method, various optimization methods such as a linear programming method and a heuristic method such as an annealing method can be used.

An example of optimization is shown below.
Equation (1) is an example of the evaluation function F when the number of STPs that satisfy the required frequency utilization efficiency is maximized.

  However, “SpectralEff (STP)” represents the frequency use efficiency in a certain STP. Area represents a set of STPs in the station design target area. # {·} Represents the number of elements of the set (here, the total number of STPs in the station placement design target area).

  Equation (2) is an example of the evaluation function F when the efficiency of the base station installation cost is further maximized.

However, C _max represents the maximum value of the base station installation cost. C _i represents the installation cost of the base station i in a certain combination of base station arrangements. In the fraction included in the formula of ρ (cost), the denominator represents the total amount when the base station is installed at the highest installation cost for all the base station installation candidates, and the numerator is the base station installation for the combination of base station arrangements. Represents the total cost.

  As described above, according to the present embodiment, it is possible to support station placement design considering base station cooperative communication.

  Note that the station placement design support apparatus 1 according to the present embodiment may be realized by dedicated hardware, or is configured by a computer system such as a personal computer, and is shown in FIG. You may implement | achieve the function by running the program for implement | achieving the function of each part of the apparatus 1. FIG.

In addition, it is assumed that an input device, an output device, and the like (both not shown) are connected to the station location design support device 1 as peripheral devices. Here, the input device refers to an input device such as a keyboard and a mouse, a reading device that reads data from a recording medium, and the like. Examples of the output device include a display device such as a CRT (Cathode Ray Tube) and a liquid crystal display device, a recording device for a recording medium, and a printing device.
The peripheral device may be connected directly to the station location design support apparatus 1 or may be connected via a communication line.

Further, a program for realizing each step performed by the station placement design support apparatus 1 shown in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. By doing so, station placement design support processing may be performed. Here, the “computer system” may include an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
“Computer-readable recording medium” refers to a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disk), and a built-in computer system. A storage device such as a hard disk.

Further, the “computer-readable recording medium” means a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, a cellular mobile communication system to which the present invention is applied includes a combination of an Orthogonal Frequency Division Multiple Access (OFDMA) scheme and MIMO technology.

DESCRIPTION OF SYMBOLS 1 ... Station location design support apparatus, 2 ... Input part, 3 ... Output part, 4 ... Database part, 5 ... Simulation model production | generation part, 6 ... Communication method determination part, 7 ... Radio | wireless characteristic calculation part, 8 ... Simulation data storage part , 9 ... Optimization unit, 21 ... Map database, 22 ... Building database, 23 ... Base station cooperation communication characteristic database

Claims (6)

An input unit for inputting in-station design conditions;
Based on the location of the base station in the station design target area specified in the station design condition and the radio wave propagation environment of each base station, the base station to which the station design target area belongs, the collaborative base station, and the non-cooperation A simulation model generator for determining a base station;
For each section of the station design target area, a communication method determination unit that determines a communication method of base station cooperative communication based on an assumed radio wave state between an affiliated base station, a collaborative base station, and a non-cooperative base station,
For each section of the station design target area, a radio characteristic calculation unit that calculates an assumed radio characteristic based on a communication method of base station cooperative communication,
An output unit that outputs the assumed radio characteristics of each section of the station design target area ,
The base station to which a certain section belongs is a base station that has the maximum expected received signal strength from each of the surrounding base stations at the center position of the section,
A base station capable of cooperating in a certain partition is a base station having an assumed received signal strength whose difference from the assumed received signal strength of the base station to which the relevant partition belongs is greater than or equal to a reference value,
A non-cooperating base station of a certain partition is a base station having an assumed received signal strength whose difference from an assumed received signal strength of a base station belonging to the relevant partition is less than a reference value.
An arrangement design support device characterized by that. The communication method determining unit
LAR calculating means for calculating a ratio (LAR) between the assumed received power of the radio wave from the affiliated base station and the assumed total received power of the radio wave from the cooperable base station in each section of the station design target area;
LFNR calculation means for calculating the ratio (LFNR) between the assumed received power of the radio wave from the affiliated base station and the assumed total received power of the radio wave from the non-cooperating base station and the assumed noise power in each section of the station design target area And having
The station location design support device is:
A base station cooperation communication characteristic database that stores information on a set of communication methods of LAR, LFNR, frequency utilization efficiency, and base station cooperation communication;
The communication method determination unit corresponds to the calculated LAR and LFNR based on information on a set of communication methods of LAR, LFNR, frequency utilization efficiency, and base station cooperative communication stored in the base station cooperative communication characteristic database. Select the communication method for base station cooperative communication with the highest frequency utilization efficiency.
The station location design support apparatus according to claim 1.   It further includes an optimization unit that performs an optimization process for maximizing the number of partitions satisfying the assumed radio characteristics criterion in the station design target area for a plurality of combinations of base station arrangements specified by the station design conditions. The station location design support apparatus according to claim 1 or 2, wherein A step of entering station design conditions;
Based on the location of the base station in the station design target area specified in the station design condition and the radio wave propagation environment of each base station, the base station to which the station design target area belongs, the collaborative base station, and the non-cooperation Determining a base station;
For each section of the station design target area, determining a communication method of base station cooperative communication based on an assumed radio wave state between the affiliated base station, a collaborative base station, and a non-cooperative base station;
For each section of the station design target area, calculating an assumed wireless characteristic based on a communication method of base station cooperative communication;
A computer program for causing a computer to execute an assumed wireless characteristic of each section of the station design target area ;
The base station to which a certain section belongs is a base station that has the maximum expected received signal strength from each of the surrounding base stations at the center position of the section,
A base station capable of cooperating in a certain partition is a base station having an assumed received signal strength whose difference from the assumed received signal strength of the base station to which the relevant partition belongs is greater than or equal to a reference value,
A non-cooperating base station of a certain partition is a base station having an assumed received signal strength whose difference from an assumed received signal strength of a base station belonging to the relevant partition is less than a reference value.
A computer program characterized by the above . In the step of determining the communication method,
Calculate the ratio (LAR) of the estimated received power of radio waves from the base station to which it belongs in each section of the station design target area and the estimated total received power of radio waves from the collaborative base stations,
Calculate the ratio (LFNR) between the assumed received power of radio waves from the affiliated base station and the assumed total received power and assumed noise power of non-cooperating base stations in each section of the station design target area,
Based on information on a set of communication methods of LAR, LFNR, frequency utilization efficiency, and base station cooperation communication, a communication method of base station cooperation communication having the maximum frequency utilization efficiency corresponding to the calculated LAR and LFNR is selected.
The computer program according to claim 4.   For a plurality of combinations of base station arrangements specified by station placement design conditions, further causing the computer to execute a step of performing an optimization process that maximizes the number of sections satisfying the criteria of assumed radio characteristics in the station placement design target area A computer program according to claim 4 or claim 5 for.

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