Method, device, and program for establishing and designing base station of mobile communication system

【0001】

[Technical field to which the invention belongs]

The present invention relates to a base station installation design method in a wireless communication system, its device and a program, and particularly to a base station installation design method such as base station arrangement and base station parameter setting in a mobile communication system.

【0002】

[Conventional technology]

A conventional base station installation design method will be described with reference to FIG. Place base station candidates in the locations indicated by black squares A02 to A06 on the service area A11, and evaluate the ratio of areas A01 and A07 to A10 covered by the base station candidate group to the service area A11 and the area coverage rate. .. Similarly, the area coverage rate is evaluated for other placement locations, and the evaluation is repeated until a base station placement pattern that achieves the desired area coverage rate is obtained. When such a trial-and-error optimal arrangement search type base station installation is performed, it is necessary to evaluate the detailed radio wave propagation characteristics over the entire service area for each base station each time the base station arrangement is given.

【0003】

As another method, there is a method in which a human narrows down the pattern to be evaluated in advance to shorten the calculation time (for example, Patent Document 1). Further, as another method, there is a method of shortening the time required for the optimum placement search by using a genetic algorithm (for example, Patent Document 2). As yet another method, it will be described with reference to FIG. 18 (for example, Non-Patent Document 1). In the method shown in Non-Patent Document 1, regularly arranged base stations are arranged in advance in the service area B01 at the location indicated by the black dot B02, and the base station does not contribute to the increase in the coverage area. The base station installation design method of sequentially deleting is shown. It is necessary to perform high-precision radio wave analysis within the entire service area for all base station candidates that are regularly arranged in advance.

【0004】

[Patent Document 1]

Japanese Unexamined Patent Publication No. 8-317458 (pages 2 to 3, FIGS. 1 to 3) [Patent Document 2]

Japanese Unexamined Patent Publication No. 2001-285923 (page 2, Fig. 1) [Patent Document 3]

Japanese Unexamined Patent Publication No. 2002-107397 [Non-Patent Document 1]

M. Kamenetsky, et. Al. Coverage Planning for Outdoor Wireless LAN Systems, 2002 International Zurich Seminar on Broadband CommunicationAccess, Transmission, Networking, Feb. 2002, pp49-1 ~ 49-6 [Non-Patent Document 2]

Proc.of International Symposium on Antennas and Propagation Society, 1991, vol.3, pp.1540-1543 [0005]

[Problems to be Solved by the Invention]

Base station installation design (also called station placement design) in a cellular system generally uses a dedicated tool, but the coverage area of the access point (AP: equivalent to the base station) is extremely narrow, and the coverage area is extremely narrow. In a wireless LAN system installed in an environment where there are many propagation obstacles such as buildings in the line-of-sight propagation area of radio waves, the simple propagation loss estimation formula used in conventional cellular system design cannot be applied, and the target Detailed radio wave analysis that takes into account the microscopic structure of the area's topography and buildings is required.

【0006】

The ray tracing method is generally used as a method for high-precision radio wave analysis, but since this method requires a large amount of processing, a trial-and-error optimal placement search type base station installation method as shown in FIG. 17 is used. If used, in some cases, it may take an unrealistic processing time to obtain a solution. Of course, it is possible to shorten the processing time by reducing the number of APs required by narrowing the service area to be designed, but in a picocell environment such as wireless LAN, a macrocell in a conventional mobile communication system -Since the number of base stations arranged per area is extremely large compared to the microcell environment, the problem is that the size of the area that can be designed within a realistic processing time does not reach the size of the required area. Occurs.

【0007】

In other words, picocell base station installation must tackle the difficult task of dealing with the increase in base station placement density while using high-precision radio wave analysis with a large amount of processing, that is, high-speed base station installation design. Achievement of the algorithm is essential.

【0008】

If the base station installation design method shown in Patent Document 1 is used, humans narrow down the placement location candidates in advance, so that the calculation time can be shortened. However, the result changes depending on the AP placement candidate selected first, and the selection of the AP placement candidate depends on ambiguous factors such as the designer's intuition and experience, and therefore an appropriate station design cannot always be guaranteed. There was a problem.

【0009】

The base station installation design method shown in Patent Document 2 can eliminate ambiguities such as the designer's intuition and experience, but the solution does not converge and diverges or oscillates depending on the prior parameter settings such as initial placement. It has been pointed out that such an unstable phenomenon occurs, and if the solution cannot be expected to converge, there is a problem that the work must be restarted from the beginning.

【0010】

In the base station installation design method shown in Non-Patent Document 1, there is no ambiguous element as in Patent Document 1 at the time of design, and the unstable phenomenon as in Patent Document 2 does not occur. However, in order to perform an effective cell layout design, the number of base stations to be arranged in advance is required to be several tens of times or more the number of base stations to be finally installed. Therefore, if the area radio wave analysis in the service area is performed in detail with all the candidate points as transmission points, a huge amount of calculation time is still required.

【0011】

Further, in any of the above-mentioned prior arts, the aim is to optimize only the installation location of the AP, and the setting method of various design parameters (transmission power, channel allocation, etc.) is not shown. Further, in the case of wide area deployment by a plurality of stations, the bias of the traffic density depending on the location becomes remarkable, but the traffic distribution is not reflected in the station design in any of the above-mentioned conventional techniques.

【0012】

The present invention relates to a base station installation design method for arranging a plurality of base stations to cover the service area in a plane given a target service area and a traffic density distribution, and details such as ray tracing and the like. Arrangement of base stations and setting of parameters that satisfy the desired traffic coverage rate (the ratio of traffic absorbed by the installed base station to all traffic in the target service area) on the premise of utilizing a radio wave analysis simulator. It is an object of the present invention to provide a base station installation design method capable of performing channel allocation and transmission power (specifically, a device and a program thereof).

【0013】

Another object of the present invention is to provide a base station installation design method, an apparatus and a program thereof, which can eliminate ambiguity without requiring human intuition or experience in selecting a base station placement location candidate. is there.

【0014】

Still another object of the present invention is to provide a base station installation design method, an apparatus and a program thereof capable of high-speed base station installation design by reducing the amount of radio wave analysis processing which occupies most of the base station installation design processing. That is.

【0015】

[Means for solving problems]

In the base station installation design method according to the present invention, a plurality of base station candidate locations are given in the service area when designing a base station installation in a mobile communication system, and the base station is installed in one of these base station candidate locations. According to the base station installation design method, the evaluation function calculation step of calculating a predetermined evaluation function according to the traffic absorption amount and / or the communication quality value at each of the base station candidate locations, and the evaluation function. It is characterized by including a base station position determination step for determining a position where a base station is installed.

【0016】

In another base station installation design method according to the present invention, a plurality of base station candidate locations are given in the service area when designing a base station installation in a mobile communication system, and radio propagation characteristic estimation is performed in any of these base station candidate locations. This is a base station installation design method in which the base station installation position is determined while using the method, and is the first method for estimating radio wave propagation characteristics in the service area with each of the base station candidate locations as a transmission point. In the service area where the step of additionally installing the base station using the first radio wave propagation characteristic estimation method having the accuracy of the above and the location of the additional installation of the base station after the base station is installed as the transmission point. The radio wave propagation characteristic estimation method is characterized by including a step of using a second radio wave propagation characteristic estimation method having a higher accuracy than the first accuracy.

【0017】

Yet another base station installation design method according to the present invention is a base station installation design method in a mobile communication system in which a service area and a traffic density distribution within this service area are given and base stations are arranged in the service area. The ratio of the total amount of traffic that can be absorbed by the base station arranged in the service area to the total amount of traffic generated in the service area is defined as the traffic coverage rate, until the traffic coverage rate exceeds the desired traffic coverage rate. It is characterized by including a base station position determination step for sequentially determining a position where a base station is installed.

【0018】

In the base station installation design device according to the present invention, a plurality of base station candidate locations are given in the service area when designing a base station installation in a mobile communication system, and the base station is installed in one of these base station candidate locations. According to the base station installation design device, the evaluation function calculation means for calculating a predetermined evaluation function according to the traffic absorption amount and / or the communication quality value at each of the base station candidate locations, and the evaluation function. It is characterized by including a base station position determining means for determining the position of the base station on which the base station is installed.

【0019】

In another base station installation design device according to the present invention, a plurality of base station candidate locations are given in the service area when designing a base station installation in a mobile communication system, and radio propagation characteristic estimation is performed in any of these base station candidate locations. It is a base station installation design device that determines the base station installation position while using the method, and is the first method for estimating radio wave propagation characteristics in the service area with each of the base station candidate locations as a transmission point. Radio propagation in the service area with the means for installing the base station using the first radio wave propagation characteristic estimation method having the accuracy of the above and the base station installation location after the base station is installed as a transmission point. The characteristic estimation method is characterized by including a means for using a second radio wave propagation characteristic estimation method having a higher accuracy than the first accuracy.

【0020】

Yet another base station installation design device according to the present invention is a base station installation design device in a mobile communication system in which a service area and a traffic density distribution within this service area are given and a base station is arranged in the service area. The ratio of the total amount of traffic that can be absorbed by the base station arranged in the service area to the total amount of traffic generated in the service area is defined as the traffic coverage rate, and until the traffic coverage rate exceeds the desired traffic coverage rate. It is characterized by including a base station position determining means for sequentially determining a position where a base station is installed.

【0021】

In the program according to the present invention, when designing a base station installation in a mobile communication system, a plurality of base station candidate locations are given in the service area, and the base station is installed in one of these base station candidate locations. A program for causing a computer to execute an installation design method, the evaluation function calculation step of calculating a predetermined evaluation function according to the traffic absorption amount and / or the communication quality value at each of the base station candidate locations, and the evaluation function calculation step. It is characterized by including a base station installation step of determining a position to install a base station according to an evaluation function.

【0022】

In another program according to the present invention, a plurality of base station candidate locations are given in the service area when designing a base station installation in a mobile communication system, and a radio wave propagation characteristic estimation method is used for any of these base station candidate locations. This is a program for causing a computer to execute a base station installation design method for determining a base station installation position, and is a method for estimating radio wave propagation characteristics in the service area with each of the base station candidate locations as a transmission point. As a transmission point, the step of additionally installing the base station using the first radio wave propagation characteristic estimation method having the first accuracy and the location of the additional installation of the base station after the base station is installed are set as transmission points. The radio wave propagation characteristic estimation method in the service area is characterized by including a step of using a second radio wave propagation characteristic estimation method having a higher accuracy than the first accuracy.

【0023】

Yet another program according to the present invention provides a service area and a traffic density distribution within the service area, and causes a computer to execute a base station installation design method in a mobile communication system in which a base station is arranged in the service area. In the program, the ratio of the total amount of traffic that can be absorbed by the base station arranged in the service area to the total amount of traffic generated in the service area is defined as the traffic coverage rate, and the traffic coverage rate is the desired traffic coverage. It is characterized by including a base station position determination step of sequentially determining a position where a base station is installed until the rate is exceeded.

【0024】

Another base station installation design method according to the present invention is a base station installation design method for designing parameters to be set for a plurality of given base stations in a service area when designing a base station installation in a mobile communication system. An evaluation function calculation step that calculates a predetermined evaluation function according to the traffic absorption amount and / or communication quality value of each of the base stations, and a base station parameter that determines a parameter for installing a base station according to this evaluation function. It is characterized by including a decision step.

【0025】

The other base station installation design device according to the present invention is a base station installation design device that designs parameters to be set for a plurality of base stations given in a service area when designing a base station installation in a mobile communication system. An evaluation function calculation means that calculates a predetermined evaluation function according to the traffic absorption amount and / or communication quality value of each of the base stations, and a base station parameter that determines a parameter for installing a base station according to this evaluation function. It is characterized by including a determination means.

【0026】

The other program according to the present invention is a program for causing a computer to execute a base station installation design method for designing parameters to be set for a plurality of given base stations in a service area when designing a base station installation in a mobile communication system. The evaluation function calculation step for calculating a predetermined evaluation function according to the traffic absorption amount and / or the communication quality value in each of the base stations, and the parameter for installing the base station are determined according to this evaluation function. It is characterized by including a base station parameter determination step.

【0027】

According to the base station installation design method according to the present invention, base stations are added sequentially, but at the time of this addition, an evaluation function in which at least one of the traffic absorption amount and the communication quality value is used as an argument is used. Since the method of defining and adding according to this evaluation function is adopted, it is possible to make a quantitative and accurate judgment in selecting the base station placement location.

【0028】

In addition, a method with a small amount of processing is used for the radio wave propagation characteristic evaluation performed when a base station is added, and a method with a large amount of processing but high accuracy is used for the radio wave propagation characteristic evaluation performed after the addition, more specifically. A method such as late lacing is applied to the above. The results of the high-precision radio wave propagation characteristic evaluation performed after the addition will be used to estimate the amount of interference when selecting the location of the newly added base station. This reduces the amount of radio wave analysis processing, which accounts for most of the base station installation design processing, and enables high-speed base station installation design.

【0029】

Further, according to the base station installation design method according to the present invention, base stations that do not contribute to the increase in traffic coverage are sequentially deleted from the above-mentioned additional base station group, and each of the additional installed existing base station groups is used. Since high-precision radio wave analysis has been completed for the entire service area with the transmission point as the transmission point, there is no need for new radio wave analysis when deleting base stations sequentially.

【0030】

The present invention having the above-mentioned characteristics eliminates the ambiguity that was a problem in Patent Document 1 in order to apply mechanical processing without requiring human intuition and experience in selecting a placement location candidate. In addition, the instability phenomenon that was a problem in Patent Document 2 does not occur, and the base station installation design can be performed by evaluating the radio wave propagation characteristics at most several times the number of base stations to be finally installed. It is possible to provide a flexible station design algorithm.

【0031】

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiments of the Invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The base station installation design algorithm of the present invention first assumes that a service area, a base station location candidate point, and a traffic distribution are given (for example, the traffic distribution is a road existing in the service area Z000-1). It can be estimated from the traffic volume of). FIG. 1 is a diagram showing a setting example of each of these parameters. Z000-1 represents the service area, and the small black circle Z000-2 indicates one of the base station placement location candidate points. In addition, the placement location candidate points may be defined three-dimensionally, and a plurality of observation points having the same XY coordinates and different Z-axis coordinates may be set. Further, when a directional antenna is used, the arrangement location candidate may be set in consideration of the orientation of the base station. That is, for example, there is a case where a plurality of placement location candidate points are set by adding information on the orientation of the base station to the same XYZ coordinate points.

【0032】

Regarding the selection of placement location candidate points, placement location candidate points in places where base stations cannot be physically installed are excluded in advance. In addition, since there may be a place that is intentionally desired to be installed at each placement location candidate point, an installation priority may be set. Although the display is omitted in Fig. 1, it is assumed that geographic information such as topography, roads, and building structure data is specified in detail in the service area Z000-1 in order to estimate the radio wave propagation characteristics with high accuracy. To do.

【0033】

Regions Z000-3 and Z000-4 show the traffic density distribution, and it is assumed that traffic with different traffic densities will be generated uniformly in each region. The traffic distribution may be given non-uniformly. In the traffic distribution model shown in Fig. 1, it is assumed that no traffic is generated in areas other than areas Z000-3 and Z000-4. In order to reduce the amount of processing for estimating propagation characteristics, base station placement candidate points in areas where traffic does not occur may be excluded. For example, it is possible to exclude base station placement location candidate points from these areas, considering that traffic does not occur in areas where rivers, ponds, etc. exist. However, in the case of an area where station placement is possible, base station placement location candidate points are not excluded even if traffic does not occur (for example, Z1-6 in Fig. 5).

【0034】

FIG. 2 is a flowchart showing a first embodiment of the base station installation design algorithm shown by the present invention. As shown in Fig. 1, it is assumed that N points (N is an integer of 2 or more) are given as base station placement location candidate points, and index numbers 1 to N are assigned to each base station placement location candidate point. It is assumed that

【0035】

In step Z0-1, set the index variable A to 1. In step Z0-2, the traffic absorption amount when it is assumed that a base station candidate is installed at the base station placement location candidate point of index number A and a cell is added is T (A), and the communication quality value (hereinafter, simply quality). Let Q (A, k) be the value), and calculate each value. Here, k indicates a channel number, and since there are four channels in the current wireless LAN, the quality value Q (A, k) is calculated for each of the four channels in which k is 1 to 4.

【0036】

The shape of the cell formed by the base station candidate is set by setting a fixed shape or by using the first radio wave propagation characteristic estimation method. As this first radio wave propagation characteristic estimation method, a radio wave propagation characteristic estimation method having a low estimation accuracy but a small amount of processing is used. For example, a radio wave propagation characteristic estimation model that attenuates by the exponential power of a distance is applicable. In this case, the propagation constant of the distance attenuation is determined according to the propagation environment in which the base station installation design is performed. Alternatively, a ray tracing method with reduced accuracy may be used as the first estimation method.

【0037】

The ray tracing method is a method used for highly accurate propagation estimation, and the ray-launching method known as one of the implementation methods is, for example, Proc. Of International Symposium on Antennas and Propagation Society, 1991, Vol. 3, pp.1540-1543 (Non-Patent Document 2) and Japanese Patent Application Laid-Open No. 2002-107397 (Patent Document 3) can use well-known methods disclosed. When high accuracy is required for this radio wave propagation estimation method, a large amount of processing is required, but the amount of processing can be reduced by lowering the accuracy. As a method of reducing the accuracy, a reduction in the number of times of reflection of radio waves can be mentioned.

【0038】

The traffic absorption amount T (A) indicates the amount of traffic absorbed by the cell formed by the base station candidate, or is absorbed by all the cells formed by the base station candidate and the existing base station. When indicating the total amount of traffic, or when using the amount of traffic generated in the area covered by the base station addition candidates calculated from the traffic density distribution, it is covered by the base station addition candidates calculated from the traffic density distribution. In some cases, the amount of traffic generated in an area other than that covered by the existing base station is used. In some cases, each of the above amounts is given as a ratio to the total amount of traffic generated in the service area.

【0039】

When the quality value Q (A, k) indicates the average of the quality values observed in the cells formed by the base station candidate, it is observed in the cell formed by the base station candidate and the cell formed by the existing base station, respectively. It may indicate the ratio at which the quality satisfies the desired value or the average value of the quality. Here, the quality value is a bit at the observation point when it is given as the desired signal reception power / (interference signal reception power + noise power) at the observation point, or when it is given as the desired signal reception power / interference signal reception power at the observation point. It may be given by various error rates such as error rate and frame error rate. Further, the quality value Q (A, k) is defined by the amount of traffic generated in the cell formed by the base station candidate and the cell formed by the existing base station, and the area where the observed quality satisfies the desired value. Alternatively, it may be specified by the ratio of the above amount to the amount of traffic generated in the entire service area. The quality value Q examines all channels that can be assigned by the system.

【0040】

Next, in step Z0-3, the evaluation function O (T (A), Q (A, k)) with the traffic absorption amount T (A) and the quality value Q (A, k) as arguments is calculated, and the memory is stored. Record in. The recorded contents in the memory in this case are as shown in FIG. That is, T (A), Q (A, k) corresponding to the four channels k = 1 to 4 at each base station candidate point indicated by the index number A (indicated as A1, A2, ...). , O ((A), Q (A, k)) will be recorded respectively.

【0041】

Here, the value of the evaluation function O to be recorded may be specified only by the traffic absorption amount T, or may be specified only by the quality value Q. An example of the evaluation function O will be described later with reference to FIG.

【0042】

In step Z0-4, it is determined whether the index variable A is less than the number of base station placement candidate points N, and if A <N, in step Z0-5, 1 is added to A, and then step Z0. Repeat after -2. If A N in step Z0-4, the process proceeds to step Z0-6. In step Z0-6, the one having the maximum value is selected from all the recorded evaluation functions O, and the base station is placed at the base station placement candidate point of the index number of the evaluation function. The channel number of the evaluation function is assigned to the base station.

【0043】

In step Z0-7, the base station newly installed in step Z0-6 is set as the transmission point, and the radio wave propagation characteristics in the entire service area are estimated and recorded. Here, the second radio wave propagation characteristic estimation method is used for estimating the radio wave propagation characteristics. As the second radio wave propagation characteristic estimation method, a method having a large estimation processing amount as compared with the first radio wave propagation characteristic estimation method but having high estimation accuracy is used. For example, a high-precision propagation characteristic analysis method such as ray tracing is applicable. The estimation result is stored in a memory, a disk, or the like. As an example of the estimation result, the received power (or propagation loss) or the received power (or propagation loss) and the delay spread, or the path consisting of the delay time and the received power (or propagation loss) for each arrival path at each observation point. Profile etc. can be considered.

【0044】

In step Z0-8, the estimation result of the radio wave propagation characteristic calculated and recorded by the second radio wave propagation characteristic estimation method related to all the base stations decided to be installed so far is referred to, and the transmission of each base station is performed. The traffic coverage rate Rc is calculated by obtaining the power and the area (cell) protected by each base station. The cell is defined by dividing the service area into minute areas and determining that the base station to which the minute area has the smallest propagation loss and the desired reception quality can be secured is the base station to which the minute area belongs.

【0045】

Here, the size and shape of each cell change not only by the radio wave propagation characteristics but also by the transmission power and the reception threshold value of each base station. Here, the reception threshold value is a determination threshold value when demodulation processing is performed in the receiver, and demodulation is not performed unless the received signal satisfies the threshold value. The reception threshold is known as the CSMA threshold or receiver threshold in the carrier sense multiple access (CSMA) method used in wireless LANs and the like. When determining the area to be protected by each base station, it is necessary to set the base station transmission power and / or the reception threshold value at the same time. The greater the transmit power and the lower the receive threshold, the larger the cell will expand and the more traffic will be generated within the cell.

【0046】

However, since there is an upper limit to the amount of traffic that can be processed by one base station, the amount of traffic generated inside the cell specified by both parameters by manipulating the transmission power and / or the reception threshold is one base station. Set the values of both parameters to maximize the amount of traffic that can be processed. Since there is a settable range for each of the transmission power and the reception threshold value, adjustments are made within each set range when operating both parameters.

【0047】

When calculating this traffic coverage rate Rc, it is possible to reconsider the channel allocation for the base station that was decided to be newly installed. Since the channel assigned to the base station decided to be newly installed is determined by using the first propagation estimation method, it is reexamined using the more accurate propagation characteristics by the second propagation characteristic estimation method. This is because channel allocation with stronger interference resistance can be expected. The reexamination process of channel allocation is performed as follows. First, the evaluation function is recalculated assuming that the newly installed base station uses each channel with the propagation characteristics estimated by the second propagation characteristic estimation method. Of each channel, use the channel that is the largest evaluation function.

【0048】

After determining the transmission power of each base station installed as described above and the size and shape of the area protected by the base station, within the service area of the total traffic absorbed by the base station group decided to be installed. The ratio to the total amount of traffic generated in the entire area is calculated, and this is defined as the traffic coverage rate Rc.

【0049】

In step Z0-9, the traffic coverage rate Rc and the predetermined traffic coverage rate Rth are compared, and if Rc Rth, the process returns to step Z0-1. If Rc> Rth is satisfied, the base station installation process is completed. (Step Z0-10).

【0050】

The first embodiment of the present invention described with reference to FIG. 2 is characterized in that base stations are sequentially added one by one. By taking the traffic volume into consideration at the stage of adding a base station, it is possible to design an appropriate base station installation according to the density of the traffic volume, and it is possible to prevent deterioration of transmission quality due to congestion. In addition, since the base station installation design is performed in consideration of the amount of interference by the second radio wave propagation characteristic estimation predicted with high accuracy such as ray tracing, it is possible to design the station with high resistance to interference. The second radio wave propagation characteristic estimation evaluation, which is highly accurate but requires a large amount of processing, is performed after the base station placement location is determined, and the first radio wave propagation characteristic estimation with a small amount of processing is performed during the base station additional search process. Use the method.

【0051】

That is, according to the present invention, high-precision radio wave propagation characteristic evaluation over the entire service area needs to be performed only for the number equal to the number of base stations to be finally installed, and all the base station placement candidate points cover the entire service area. Compared with the method of Non-Patent Document 1 which requires highly accurate evaluation of radio wave propagation characteristics, it is possible to shorten the time required for base station installation design. Further, as compared with the prior art disclosed in Patent Document 1, the present invention enables a station design that always has a certain effect regardless of the experience and intuition of the layout designer. Further, as compared with the prior art disclosed in Patent Document 2, it can be pointed out that the design processing time can be significantly shortened as in the case of comparison with Non-Patent Document 1.

【0052】

FIG. 4 is a diagram showing an example of the evaluation function O having the traffic absorption amount T and the quality value Q as arguments. The higher the traffic absorption amount T and the higher the quality value Q, the larger the evaluation function is set. By introducing the evaluation function as shown in Fig. 4, it becomes possible to handle the two evaluation indexes, the traffic absorption amount and the quality value, in a unified manner when designing the base station installation.

【0053】

As an example of the evaluation function O, O = Q * T or O = a * Q + b * T (a and b are constants) or O = α * Q + (1-α) * T (α is It is a weighting coefficient and can be 0 <α <1) or the like, but is not limited to this. In each of the above equations, * indicates multiplication.

【0054】

Further, when the installation priority P is set for each of the placement location candidate points, the evaluation function O may be further multiplied by the installation priority P (or added after weighting) and used as the evaluation function. .. The evaluation function O may have the same value even if it is different A (placement location candidate point) and k (channel). This may occur because the traffic absorption of each base station is limited to the maximum traffic that the base station can accommodate. Therefore, different evaluation functions O'(T', Q') may be used as auxiliary judgment materials. For example, in T'in the evaluation function O', O'different from the evaluation function O can be used as a secondary judgment material by not considering the maximum traffic that can be accommodated by the AP.

【0055】

Next, how the evaluation function O is obtained for a certain base station placement candidate will be specifically described. FIG. 5 is a drawing schematically explaining how the evaluation function O is determined in the present invention. In FIG. 5, the service area Z1-1 is given, and the traffic distribution is given as the shaded areas Z1-7 and Z1-8 within the service area Z1-1. Traffic generation densities are different in regions Z1-7 and Z1-8. The black small circle Z1-9 is a base station installation location candidate point, and the black squares Z1-4 to Z1-6 are the existing base stations or the method according to the present invention to be installed in step Z0-6 of FIG. Indicates the base station determined to be. The white square Z1-2 indicates a base station candidate installed at a certain placement location candidate point, and how the evaluation function O is obtained for the base station candidate will be described below.

【0056】

First, cells Z1-3 formed by the base station candidate Z1-2 are defined. At this time, the shape of cell Z1-3 is obtained in step Z0-2 of FIG. The cell Z1-3 may be determined by allocating a fixed shape in advance, the transmission power emitted by the base station candidate Z1-2, and the propagation loss obtained by the first radio wave propagation characteristic estimation method. .. In the latter case, the transmission power is determined as follows. That is, the amount of traffic generated in the cell is either the transmission power adjusted to be the maximum amount of traffic that can be processed by one base station, or the maximum transmission power, whichever is lower.

【0057】

The following can be considered as an example of the method of obtaining the transmission power. First, assuming a cell when the transmission power is maximized, the amount of traffic absorbed in the cell is calculated, and if the calculated amount of traffic is less than the maximum amount of traffic that can be processed by one base station, The transmission power is the maximum power of this base station, and the cell is the above-calculated cell. When the calculated traffic volume is larger than the maximum traffic volume that can be processed by one base station, the transmission power of this base station is sufficient to cover the cell that absorbs the traffic corresponding to this maximum traffic volume. Let it be power.

【0058】

The traffic absorption amount T is equal to the total amount of traffic generated inside the cell Z1-3. That is, it is the amount of traffic generated in each part of the regions Z1-7 and Z1-8 included in the cell Z1-3.

【0059】

The quality value Q is given by the function of the sum of the interferences from the existing base stations Z1-4 to Z1-6 received by the placement location candidate Z1-2, so that the lower the sum of the interferences, the higher the sum. Set. For example, the quality value Q is specified to be inversely proportional to the total interference. The amount of interference from each existing base station Z1-4 to Z1-6 is determined by the interference wave transmission power and the propagation loss to the placement location candidate. The interference wave transmission power may be a fixed value or may be set in proportion to the magnitude of the traffic loaded on the existing base station. The propagation loss from each existing base station to the placement location candidate point is calculated by the second radio wave propagation characteristic estimation method, and the stored highly accurate propagation loss estimation result is applied.

【0060】

After obtaining the traffic absorption amount T and the quality value Q as described above, it is calculated by the evaluation function O illustrated in FIG.

【0061】

According to the embodiment relating to the evaluation function O determination described in FIG. 5, it is possible to design the base station installation in consideration of the amount of traffic generated in the cell formed by the base station candidate and the amount of interference received by the base station. .. When a base station is installed at a base station placement location candidate point, the installation location with a large amount of traffic processed by the base station and the installation location with a small amount of interference are preferentially installed. And.

【0062】

FIG. 6 shows another embodiment relating to the regulation of the traffic absorption amount T in FIG. In FIG. 6, Z2-1, Z2-4, and Z2-5 indicate existing base stations or base stations determined to be installed in step Z0-6 of FIG. 2 using the method according to the method of the present invention, respectively. , Z2-9 indicate base station candidates. The cells formed by the existing base stations of Z2-1, Z2-4, and Z2-5 are Z2-2, Z2-3, and Z2-6, respectively, and the cells formed by the base station candidate Z2-9 are. It is Z2-10.

【0063】

When determining the cells formed by the existing base stations (Z2-1, Z2-4, Z2-5), they are calculated and stored by the second radio wave propagation characteristic estimation method (Z0-7 in Fig. 2). It is assumed that the result of highly accurate propagation loss estimation is applied, and that appropriate base station selection is performed for each minute area in the service area. Here, the base station selection for each minute area means the act of connecting to the base station having the smallest propagation loss that satisfies the desired reception quality when the terminal exists in a certain minute area, or the desired reception quality. It refers to the act of connecting to a base station that can realize communication with the highest reception quality or reception power. That is, by selecting the base station, a cell boundary is formed so that the best communication quality can be ensured at each location in the service area.

【0064】

However, when selecting a base station, each minute area does not select the base station candidate Z2-9, and the cell boundary of the base station candidate Z2-9 is obtained by a fixed shape or the first radio wave propagation characteristic estimation method. It is shaped like the Z2-10. The base station in charge of the cell absorbs the traffic generated within the cell boundary formed in this way.

【0065】

A limit value is set for the amount of traffic that can be accommodated by one base station, and the lower of the amount of traffic generated within the cell boundary determined above and the amount of allowable traffic of the base station is accommodated in the cell. It can also be the amount of traffic.

【0066】

In another embodiment relating to the regulation of the traffic absorption amount T shown in FIG. 6, the existing base stations Z2-4 and Z2-5 already cover when calculating the traffic absorption amount T for the cell Z2-10. It is characterized by excluding traffic generated in areas Z2-7 and Z2-8. By excluding the traffic already absorbed by the existing base station from the traffic amount T of the newly added base station, it is possible to estimate the traffic amount T more accurately.

【0067】

FIG. 7 shows a further embodiment relating to the provision of the traffic absorption amount T. In FIG. 7, Z6-1, Z6-4, and Z6-5 indicate existing base stations or base stations determined to be installed in step Z0-6 of FIG. 2 using the method according to the present invention, respectively. -9 indicates a base station candidate. The cells formed by the existing base stations Z6-1, Z6-4, and Z6-5 are Z6-2, Z6-3, and Z6-6, respectively, and the cells formed by the base station candidate Z6-9 are Z6. -10. When determining the cell formed by the existing base station, the result of highly accurate propagation characteristic loss estimation calculated and stored by the second radio wave propagation characteristic estimation method (step Z0-7 in FIG. 2) is applied. .. Further, the cell formed by the base station candidate Z6-9 is obtained by using the result of the propagation characteristic estimation calculated by the first radio wave propagation characteristic estimation method. It is assumed that an appropriate base station selection is performed for each minute area in the service area.

【0068】

Here, the base station selection for each minute area means the act of connecting to the base station having the smallest propagation loss that satisfies the desired reception quality when the terminal exists in a certain minute area, or the desired reception quality. It refers to the act of connecting to a base station that can realize communication with the highest reception quality or reception power. That is, by selecting the base station, a cell boundary is formed so that the best communication quality can be ensured at each location in the service area. The base station in charge of the cell absorbs the traffic generated within the cell boundary formed in this way.

【0069】

A limit value is set for the amount of traffic that can be accommodated by one base station, and the lower of the amount of traffic generated within the cell boundary determined above and the amount of allowable traffic of the base station is accommodated in the cell. It can also be the amount of traffic.

【0070】

In a further embodiment relating to the provision of the traffic absorption amount T shown in FIG. 7, the total amount of traffic absorbed by the existing base stations Z6-1, Z6-4, Z6-5 and the base station candidate Z6-9 is used as the traffic. The feature is that the absorption amount is T.

【0071】

By setting the traffic absorption amount T as the total amount of traffic absorbed by the existing base stations in the service area and the base station candidates, a new base station candidate that achieves the maximum traffic absorption amount in the entire service area is added. It can be selected as a base station.

【0072】

FIG. 8 schematically shows another embodiment relating to the regulation of the quality value Q in FIG. Assuming the evaluation terminal Z3-6 shown by the white triangle connected to the base station candidate Z3-5 shown by the white square, the ratio of the desired signal reception power and the interference signal reception power observed in the evaluation terminal Z3-6 ( The quality value Q is specified by the DU ratio). The propagation loss calculated by the first radio wave propagation characteristic estimation method is used for the calculation of the desired signal power. When the distance attenuation amount attenuated by the exponential power of the distance is used as the first radio wave propagation characteristic estimation method, the linear distance Z3-10 from the base station candidate Z3-5 to the evaluation terminal Z3-6 is used as the distance.

【0073】

Z3-1 to Z3-3 indicate the existing base stations or the base stations determined to be installed in step Z0-6 of FIG. 2 using the method according to the present invention, respectively. The calculation of the interference signal power is determined by the propagation loss from each base station Z3-1 to Z3-3 to the evaluation terminal Z3-6 and the interference signal transmission power emitted by each existing base station. When the interference signal transmission power emitted from each existing base station Z3-1 to Z3-3 is fixed, it may be determined according to the amount of traffic applied to each existing base station. The propagation loss from each existing base station to the evaluation terminal is estimated by the second radio wave propagation characteristic estimation method, and a stored highly accurate propagation loss value is used.

【0074】

The evaluation terminal Z3-6 is generated in various places in the cell Z3-4 formed by the base station candidate Z3-5, the DU ratio is obtained, and the quality value Q is defined by averaging. At that time, the place where traffic does not occur in the cell Z3-4 may not be the target of the averaging process. Alternatively, weighting may be performed and averaged according to the magnitude of the traffic density in the cell Z3-4.

【0075】

According to another embodiment relating to the regulation of the quality value Q shown in FIG. 8, the DU ratio observed by the virtual evaluation terminal is used for the quality value, and the DU ratio is averaged in the cells formed by the base station candidates. It is possible to perform a more rigorous quality evaluation by looking over the inside of the cell.

【0076】

FIG. 9 schematically shows a further embodiment regarding the definition of the quality value Q in FIG. The evaluation terminal Z4-4 is scanned over the entire service area, the DU ratio is obtained at each evaluation terminal placement location, and the ratio that satisfies the required DU ratio is defined as the quality value Q. The evaluation terminal shall be connected to an existing base station or base station candidate capable of communicating with the highest received power from the place where the terminal is installed, and the interference power shall be an existing base station other than the base station to be connected to the terminal. It is the sum of the interference signal power from the base station or the base station candidate. The quality value is determined so that the smaller the sum is, the higher the quality value is.

【0077】

In the example of FIG. 9, the evaluation terminal Z4-4 is connected to the existing base station Z4-2, and therefore the interference power is generated from the existing base stations Z4-1, Z4-3 and the base station candidate Z4-5 to the evaluation terminal Z4-. It will come to 4. Locations in the service area where traffic does not occur may not be evaluated to measure the quality value Q. Alternatively, the quality value Q may be specified by weighting and adding the DU ratio according to the magnitude of the traffic density in the service area.

【0078】

The propagation loss connecting the base station candidate and the evaluation terminal is given by the propagation loss calculated by the first radio wave propagation characteristic estimation method. For the propagation loss connecting the existing base station and the evaluation terminal, the propagation loss value estimated and stored by the second radio wave propagation characteristic estimation method is used. When the interference signal emission power emitted from each existing base station and base station candidate is fixed, it may be determined according to the amount of traffic applied to each base station.

【0079】

According to a further embodiment relating to the regulation of the quality value Q shown in FIG. 9, when the base station candidate is added, not only the quality value observed in the base station candidate but also the base station candidate is added. It is possible to design a base station installation in consideration of the effects of quality value deterioration observed in other cells.

【0080】

FIG. 10 shows the station station design device D001 for realizing the operation flow shown in FIG. 2 as a schematic functional block. The input information 1 is the map information of the service area, the traffic distribution information, the base station installation candidate point information, and the predetermined traffic coverage rate Rth (see step Z0-9 in FIG. 2). The evaluation function O measurement recording unit 2 calculates the traffic absorption amount T and the quality value Q using the first radio wave propagation estimation engine 3 for executing the first radio wave propagation estimation method described above, and these T and the quality value Q are calculated. The evaluation function O corresponding to Q is calculated and recorded in the memory unit (not shown in particular) as shown in FIG.

【0081】

Base station installation, radio wave propagation characteristic evaluation unit 4 decides to install the base station at the base station installation location candidate point where the maximum evaluation function O is obtained, and executes the second radio wave propagation estimation method described above. The second radio wave propagation estimation engine 5 is used to estimate the radio wave propagation characteristics in the service area and record the radio wave propagation characteristics in the service area with the newly installed base station as the transmission point.

【0082】

The traffic coverage evaluation unit 6 obtains the transmission power of each base station and the area protected by each base station, and calculates the traffic coverage Rc. The station station design end determination unit 7 determines whether or not the traffic coverage rate Rc exceeds the predetermined traffic coverage rate Rth, and if it exceeds, determines the station station design end. Then, as the output information 8, the parameter setting result such as the base station arrangement result, the channel, and the transmission power is output.

【0083】

FIG. 11 is a flowchart showing a second embodiment of the base station installation design algorithm of the present invention. This second embodiment is characterized in that it is subsequently performed after the treatment described in the first embodiment of FIG. Step Z5-1 shows the entire process of the first embodiment described in FIG. After the processing described in the first embodiment is completed, in step Z5-2, the modified traffic coverage rate Rm, which is the traffic coverage rate when the existing base stations are deleted, is obtained, and the first embodiment in FIG. 2 is obtained. The difference between the traffic coverage ratio Rc and Rm finally obtained is obtained, and the base station D having the minimum Rc-Rm is obtained.

【0084】

At this time, Rm is obtained by using the estimation result obtained by using the second radio wave propagation estimation method in Z0-7 of Fig. 2. As an example, first, when an existing base station to be deleted is determined and it is assumed that the base station is deleted, a cell formed by each of the other base stations is obtained, and the service area of the total amount of traffic covered by the cell is obtained. Rm can be calculated by giving Rm by the ratio to the total traffic volume generated in the entire area.

【0085】

Instead of this step Z5-2, that is, instead of selecting the base station with the smallest Rc-Rm, the evaluation function O (T, Q) when each base station is deleted is calculated and deleted. The base station having the maximum evaluation function O may be selected as the deletion candidate base station. In this case, the traffic coverage rate Rm when the base station selected by the evaluation function is deleted is obtained, and the process proceeds to the next step.

【0086】

In step Z5-3, it is determined whether or not the modified traffic coverage rate Rm when the base station D is deleted is still larger than the traffic coverage rate threshold value Rth. If Rm> Rth is satisfied, base D is deleted from the existing base station in step Z5-4, and if not satisfied, the process proceeds to step Z5-6 to complete the base station installation design.

【0087】

After deleting the base station D in step Z5-4, the transmission power of each base station and the area protected by each base station are obtained again in step Z5-5, and the traffic coverage rate Rc is recalculated. The detailed processing in step Z5-5 is equivalent to the processing in step Z0-8 in the first embodiment described in FIG. After completing step Z5-4, repeat Z5-2 and subsequent steps.

【0088】

According to the second embodiment of the present invention described with reference to FIG. 11, it is possible to delete a useless base station from the base stations installed in the first embodiment. In the first embodiment described in FIG. 2, the processing amount of the cell to be added is small, but the base station is wastefully installed due to the use of the first radio wave propagation characteristic estimation method having low estimation accuracy. That is, there is a possibility that some base stations do not contribute much to the improvement of the traffic coverage rate. In the second embodiment, by deleting such useless base stations, it is possible to realize the required minimum number of base station arrangements.

【0089】

FIG. 12 shows the station design device D002 for realizing the operation flow shown in FIG. 11 as a schematic functional block diagram, and the same parts as those in FIG. 10 are indicated by the same reference numerals. It operates by being connected to the subsequent stage of the station station design device D001 shown in FIG. 10, and the deleted base station determination unit 9 receives the output of the station station design device D001 shown in FIG. 10 to determine the base station to be deleted. Is what you do. The method of determining the deletion base station is the processing of steps Z5-2 to Z5-5 in the flow of FIG.

【0090】

The station placement design end determination unit 10 determines the end of the deletion base station determination, and the base station deletion unit 11 deletes the base station determined by the deletion base station determination unit 9. The final output information 8 ́ obtained in this way is obtained, and the parameter setting results such as the base station arrangement result, channel, transmission power, etc. deleted by the base station deletion unit 11 from the output information 8 shown in FIG. 10 are obtained. can get.

【0091】

In some cases, it may be desirable to design a cell in a wider area than the area described with reference to FIGS. 5 to 9. An example of the cell design method in the present invention in such a case will be described with reference to FIG. FIG. 13 shows a case where a cell design in a wider area than that in FIG. 5 and the like is performed. The design area shown in Fig. 13 is divided into two areas X01 and X02 that overlap each other. First, the area X01 is stationed by the cell design method of the present invention described above. The group of base stations designed in this way is shown in FIG. 13 as X03-i (i = 1 to 4).

【0092】

After designing area X01, design area X02 next. Area X02 shown in thick frame overlaps with area X01 shown in thin frame, and area X02 contains base stations X03-4 and X03-3 already designed in X01. When designing area X02, base stations X03-3 and X03-4 are considered as existing base stations, and cell design is performed according to the above-mentioned cell design procedure for placement location candidate points other than the base station installation location.

【0093】

For example, when designing a cell for the entire prefecture, it is necessary to design a cell for a huge number of base station placement location candidates, and it is expected that the memory and the required amount of calculation will be enormous. Will be done. Even in the case of designing such a wide area cell, according to the present invention, it is possible to reduce the memory and the amount of calculation by extracting a plurality of areas divided into small pieces. At that time, by intentionally superimposing the areas adjacent to each other, when designing the cell of a certain area A, the cell in consideration of the interference from the already installed base station in the area B adjacent to A. Design is possible.

【0094】

Further, when a base station is actually installed in the target service area, the cell design according to the present invention described above is performed after setting the position information, setting channel information, transmission power information, etc. of the base station in advance. This makes it possible to design a new additional base station in consideration of these interferences.

【0095】

In addition, as described in paragraph "0031", information including XYZ coordinates and installation direction may be given as a base station placement location candidate point, but if there are multiple types of antennas that can be used, the type of antenna and The reception characteristics differ depending on the installation orientation. Therefore, when there are a plurality of types of antennas that can be used, a more detailed design can be performed by calculating the evaluation function with the antenna type and the installation direction as parameters. In that case, in paragraph "0035", the communication quality value Q (A, k) is defined as a function of the location A where the base station is installed and the channel k to be used, but Q (A, k, t, d). Therefore, it is necessary to add the type t of the antenna and the installation direction d of the base station as elements.

【0096】

The processing flow when the communication quality value is Q (A, k, t, d) will be described with reference to FIG. In step Z0-2 of FIG. 2, the quality value Q is calculated for all combinations of the base station installation location candidate point A, the channel k, the antenna type t, and the installation direction d. The evaluation function calculated in step Z0-3 is O (t (A), Q (A, k, t, d)), and the recorded contents in the memory are as shown in FIG. That is, T (A), Q (A,) corresponding to the channel k, the antenna type t, and the installation direction d at each base station candidate point indicated by the index number A (indicated as A1, A2, ...). k, t, d), O (T (A), Q (A, k, t, d)) will be recorded respectively.

【0097】

In this example, the number of channels is 3, the number of antenna types is 2, and the installation orientation is 2 patterns for the antenna t = 1 and the installation orientation is 4 patterns for the antenna t = 2. The installation orientation is changed according to the directivity of the antenna. For example, in the case of an omnidirectional antenna, since it has no meaning to change the installation direction, the number of directions is determined by the sharpness of the directivity so that only one pattern is used. In step Z0-6, the installation location candidate point, channel, antenna type, and installation direction that obtain the maximum evaluation function are set in the base station.

【0098】

In addition, in the station placement design devices D001 and D002 shown in FIGS. 10 and 12, when the antenna type and the installation direction are added as the elements of the quality value Q, the base station arrangement result, the channel, and the output information 8,8 ́ In addition to the transmission power, the antenna type and installation direction will be output at the same time.

【0099】

As described above, by calculating the evaluation function, it is possible to select an appropriate antenna type from a plurality of selectable antenna types and determine an appropriate installation orientation of the antenna.

【0100】

Further, although the present invention can shorten the calculation processing time as compared with the prior art, it may be necessary to perform a large number of calculation processing depending on the number of base station placement location candidate points and reception quality observation points. is there. In order to further shorten the time required for this processing, the processing program for executing the present invention can be changed to a form capable of parallel calculation and executed. When parallel calculation is performed, it is possible to perform calculations simultaneously using a plurality of computers, so that the calculation time can be shortened. After performing parallel calculation, the results obtained by each computer are totaled and processing is continued. As a place where parallel calculation is effective, there is a place where the parameter for obtaining the maximum evaluation function is searched by using the first radio wave propagation characteristic estimation method in steps Z0-1 to Z0-5 in FIG.

【0101】

Propagation analysis by the first propagation estimation method needs to be calculated between all traffic existence points (referred to as T points) and base station installation location candidate points. In the flow shown in Fig. 2, it was described that the propagation characteristics by the first radio wave propagation characteristic estimation method are calculated every time the quality value Q and the traffic absorption amount T are calculated, but in terms of implementation, they are calculated in advance. Therefore, when calculating the quality value Q and the traffic absorption amount T, the recorded values are extracted and used. Since the propagation characteristic calculation using the first radio wave propagation estimation method using all the base station placement location candidate points as transmission points can be calculated independently at each base station placement location candidate point, parallel processing can be performed. In addition, the evaluation function can be calculated independently for each installation condition, and parallel processing can be performed. The parallel processing method will be described in detail below.

【0102】

The target for which the propagation characteristics are to be obtained is the number of traffic generation points N × the number of base station installation location candidate points M. As shown in Fig. 15, there are N * M ways of propagation characteristics to be obtained from propagation characteristics 11 to NM (* means multiplication). This is divided by the number of computers P that can be processed in parallel, and each computer is made to calculate the propagation characteristics for N * M / P. By combining the results obtained by each computer, all the results with propagation characteristics 11 to NM can be obtained. Since a communication overhead is required to combine the results of parallel processing, α is added to the calculation time in the figure.

【0103】

In addition, when the computing power of computers that perform parallel processing is different, if the same processing amount is divided, there will be a large gap in the time until the result is obtained, and other computer resources will be used until the computer with slow processing speed obtains the result. It can be wasted. For this reason, the objects that need to be calculated are divided into smaller units (at least for each propagation characteristic), and each computer is made to calculate. It is also possible to use the method of processing (see Fig. 16).

【0104】

It is necessary to calculate the evaluation function for each installation parameter by the number of patterns of the number of candidate installation locations (M) × the number of channels (C) × the number of antenna types (T) × the number of installation directions (D). In order to speed up this, parallel processing of the calculator is performed in the same manner as described above. Since the total number of patterns is M * C * A * D, when using a computer group with the same processing capacity (number of computers P), each computer should be processed with M * C * A * D / P. Assign and calculate. When using a calculator with different processing power, the same procedure as in FIG. 16 is performed.

【0105】

As described above, the calculation time can be shortened by performing the estimation using the first propagation characteristic estimation method and the calculation of the evaluation function in parallel.

【0106】

Further, the present invention can also be used to determine a channel, transmission power, antenna type, installation direction, etc. for a base station actually installed in advance. For that purpose, specify the position of the base station that has already been installed as a base station installation location candidate point, and set the criterion of step Z0-9 in Fig. 2 to all base station installation candidate points instead of the traffic coverage rate. This can be achieved by completing the installation of. As a result, it is possible to design the channel, transmission power, antenna used, and installation direction in each base station to appropriate values.

【0107】

In this method, since the base station installation location is determined in advance, it is not necessary to perform propagation estimation with a large number of base station installation location candidate points as transmission points. Therefore, it is possible to reflect a more accurate propagation estimation result by using only the second propagation estimation method without using the first propagation estimation method in step Z0-2.

【0108】

In the above embodiment, the service area has been described as a two-dimensional one, but this is an example for facilitating the grasp of the contents, and is similarly applicable to a three-dimensional space. Further, it goes without saying that the flow of each operation process described above can be stored as a program in a recording medium in advance, read by a computer, and executed.

【0109】

[Effect of the invention]

According to the present invention, when adding base stations sequentially, a method is adopted in which an evaluation function in which at least one of a traffic absorption amount and a communication quality value is used as an argument is defined and added according to this evaluation function. Therefore, it is possible to make a quantitative judgment in selecting the location of the base station, which has the effect of not being influenced by human intuition and experience.

【0110】

Further, according to the present invention, a method with a small amount of processing is used for the radio wave propagation characteristic evaluation performed when determining a base station to be added from the base station candidates, and the radio wave propagation characteristic evaluation performed after the determination is performed. A method with a large amount of processing but high accuracy is applied to, and the result of the high-precision radio wave propagation characteristic evaluation performed after this addition is used to estimate the amount of interference when selecting the location of the newly added base station. This has the effect of reducing the amount of radio wave analysis processing, which accounts for most of the base station installation design processing, and enabling high-speed base station installation design.

【0111】

Further, according to the present invention, it is possible to realize the minimum required number of base station arrangements by sequentially deleting base stations that do not contribute to the increase in traffic coverage from the above additional base station group, and this additional installation. Since high-precision radio wave analysis has been completed for the entire service area with each of the existing base stations as the transmission point, there is no need for new radio wave analysis when deleting base stations sequentially, so high speed It has the effect of being able to process.

[Simple explanation of drawings]

FIG. 1 is a diagram showing regulations for a service area, base station placement candidate points, and traffic distribution.

FIG. 2 is a flowchart showing the operation of the first embodiment in the base station installation design algorithm of the present invention.

FIG. 3 is a diagram showing an example of recorded contents in a memory of a traffic absorption amount T, a quality value Q, and an evaluation function O at each base station candidate point.

FIG. 4 is a diagram showing an example of the evaluation function O.

FIG. 5 is a schematic view showing an embodiment of the present invention.

FIG. 6 is a diagram showing another embodiment relating to the regulation of the traffic absorption amount T.

FIG. 7 is a diagram showing a further embodiment relating to the regulation of the traffic absorption amount T.

FIG. 8 is a diagram showing another embodiment relating to the regulation of quality value Q.

FIG. 9 is a diagram showing a further embodiment regarding the regulation of quality value Q.

FIG. 10 is a functional block diagram showing an apparatus configuration according to a first embodiment of the present invention.

FIG. 11 is a flowchart showing the operation of the second embodiment in the base station installation design algorithm of the present invention.

FIG. 12 is a functional block diagram showing an apparatus configuration of a second embodiment of the present invention.

FIG. 13 is a diagram illustrating an example of performing a cell design over a wider area in an embodiment of the present invention. [Fig. 14] Traffic absorption amount T, quality value Q, and evaluation function O at each base station candidate point. It is a figure which shows another example of the recorded content on a memory.

FIG. 15 is a diagram showing an example in which the processing in the embodiment of the present invention is processed in parallel using a plurality of computers.

FIG. 16 is a diagram showing another example in which the processing in the embodiment of the present invention is processed in parallel using a plurality of computers.

FIG. 17 is a diagram for explaining a conventional technique.

FIG. 18 is a diagram for explaining another prior art.

[Explanation of symbols]

1 Input information 2 Evaluation function O Measurement recording unit 3 First radio wave propagation estimation engine 4 Base station installation, radio wave propagation characteristic evaluation unit 5 Second radio wave propagation estimation engine 6 Traffic coverage rate evaluation unit 7,10 Station design end judgment unit 8 Output information 9 Deleted base station determination unit 11 Base station deletion unit D001, D002 Station design device