JP2002051368A - Base station, mobile terminal, radio data communication system, and radio data communication network constructing method and computer-readable recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base station, a mobile terminal, a radio data communication system, a radio data communication network constructing method, and a computer readable recording medium, capable of making it difficult to generate delays in radio data communication and to generate congested state, even if traffic becomes concentrated. SOLUTION: Respective base stations are arranged, so that the physical areas can be overlapped over a wide range, and a mobile terminal 14 positioned in the overlapped area detects data communication traffic quantity from the line state information of the base stations, with which the mobile terminal 14 is about to communicate, and the activation information of the peripheral base stations preliminarily announced from the base stations, and selects the base station whose traffic quantity is small, and starts communication with the base station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio data communication system, in which base stations are arranged in accordance with the amount of communication traffic, and base stations and mobile terminals for efficient communication between the base stations and mobile terminals. The present invention relates to a wireless data communication system, a wireless data communication network construction method, and a computer-readable recording medium.

[0002]

2. Description of the Related Art In a conventional communication system between a base station arrangement and mobile terminals, FIG. 7 shows an overlap of radio wave coverage from a base station. As shown in the figure, when base stations A and 54, base stations B and 55, and base stations C and 56 are arranged, the radio wave coverage of each base station (hereinafter, physical area) is
1b, a physical area 52b, and a physical area 53b. Here, in the base station A / 54, the area that can communicate with the mobile terminal is the physical area 51b. However, in relation to surrounding base stations, a hexagonal area that is actually in charge of communication with a mobile terminal is a cell (cell: logical area) and is a cell (1) · 51a. Similarly, base station B
At 55, it becomes Cell (2) · 52a, and at base station C · 56, it becomes Cell (3) · 53a. Here, an overlapping area in which two or more of the physical area 51b, the physical area 52b, and the physical area 53b overlap is referred to as an overlapping area 57. As shown in the figure, the overlapping area 57 is only the peripheral part of each physical area, and when the mobile terminal moves between base stations, the base station is switched in the overlapping area.

In recent years, as the number of users of mobile terminals has increased, a large amount of traffic has been generated in some places, and in order to increase the number of base stations accommodated, TDMA (Time Division Multiple Access), FDMA, (Frequency division multiple access),
Techniques such as CDMA (code division multiple access) are used.

[0004]

As described above, conventionally, a single base station controls the area in charge, so if traffic concentrates, wireless data communication may be delayed or wireless data communication may be delayed due to congestion. There was a problem that communication became impossible. Further, in order to cope with a large amount of traffic, there is a problem that the scale of the base station (the size of the device) is increased and the cost is increased. In addition, because the frequency of allocation is determined, and furthermore, the installation location is limited due to the relationship with the surrounding base stations, so that base stations are added or the frequency within the allocated frequency is increased in response to the increase in traffic volume. However, there is a limit to increasing the number of channels, and there is a problem that it cannot easily cope with an increase in traffic volume. Also, even if the number of users (traffic volume) can be predicted in each region in advance,
It is only possible to install base stations in accordance with the characteristics of the area (the amount of traffic), and there is a problem that the degree of freedom is low only in units of cells, and furthermore, depending on the relationship with surrounding base stations, Even in a small number of areas, it is necessary to install a large-capacity base station, so that there is a problem that the cost increases. In addition, it is difficult to move the installation location of the base station once installed, or to adjust the traffic capacity by increasing or decreasing the number of base stations, and there is a problem that the expandability of the system is low.

[0005] The present invention has been made in view of the above-mentioned circumstances, and a base station which is less likely to cause delay in wireless data communication and to be less congested even when traffic is concentrated.
It is an object to provide a mobile terminal, a wireless data communication system, a wireless data communication network construction method, and a computer-readable recording medium. In addition, even if a large amount of traffic is handled, the base station, mobile terminal, wireless data communication system, wireless data communication network construction method, and computer readable which do not need to increase the scale (size of the device) of each base station It is intended to provide a recording medium. Further, base stations, mobile terminals,
An object of the present invention is to provide a wireless data communication system, a wireless data communication network construction method, and a computer-readable recording medium. Furthermore, the number of users (traffic volume) is predicted in advance for each region, and base stations, mobile terminals, wireless data communication systems, and wireless data communication networks are constructed in which base stations are installed in accordance with regional characteristics (traffic volume). It is an object to provide a method and a computer-readable recording medium. Still another object of the present invention is to provide a base station, a mobile terminal, a wireless data communication system, a wireless data communication network construction method, and a computer-readable recording medium method with high system expandability.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. In a wireless data communication system according to the present invention, a base station and a mobile terminal use different wireless data transmissions at different single frequencies. In a wireless data communication system that performs communication, each base station is installed such that radio wave coverage from a plurality of base stations has an area that overlaps over a wide range, and each base station is a base station that shares the overlapping area. The mobile terminals are set to have different carrier frequencies, and the mobile terminal includes means for detecting a data communication traffic state of each base station in the overlapping area and selecting a base station having a small traffic amount.

Accordingly, in the wireless data communication system, the base stations are arranged so as to have an area where the radio wave reach overlaps over a wide range, and the mobile terminal transmits the data which is the wireless data communication amount of each base station in the overlapping area. Since the communication traffic amount is detected and a base station having a small traffic amount can be selected from the communication traffic amount, it is possible to avoid concentration of traffic from a mobile terminal to one base station.

[0008] In the mobile terminal according to the present invention,
A wireless data communication system in which a base station and a mobile terminal each perform wireless data communication at a different single frequency, and are installed so that radio wave coverages of a plurality of base stations have an area where a wide range overlaps, and an overlapping area. In a mobile terminal in a wireless data communication system in which the carrier frequency of each base station is set to be different in the base station sharing the, in the overlapping area,
It is characterized by comprising means for detecting a data communication traffic state of each base station and selecting a base station having a small traffic amount.

Thus, the mobile terminal detects the data communication traffic amount, which is the wireless data communication amount of each base station, in the area where the radio wave coverages from a plurality of base stations overlap, and among them, the base station having the smaller traffic amount Since a station can be selected, the mobile terminal can perform wireless data communication while avoiding a congested base station.

[0010] In the mobile terminal according to the present invention, the mobile terminal, in the overlapping area, is notified of the remaining packet number information of the data being communicated and the reservation number of another mobile terminal, which is notified from a base station to be communicated with. Receiving line state information including information, line state determining means for determining whether communication is possible, operation information of peripheral base stations notified from the base station, registered mobile terminal number information,
And a base station detecting means for detecting a base station having a smaller data communication traffic amount based on communication traffic information including usage frequency information of the mobile terminal.

Thus, the communication terminal determines whether or not communication is possible with the base station based on the line state information broadcast from the base station with which communication is to be performed, and if possible, performs communication. Based on communication traffic information broadcast from the same base station, it is possible to select a base station having a smaller data communication traffic amount from neighboring base stations.

In the base station according to the present invention, claim 3
In the base station mediating wireless data communication with the mobile terminal described in the above, the number of remaining packets of data being communicated to the mobile terminal,
The communication status information including the line status information including the number of reservations of the mobile terminal and the operation information of the base station around the mobile terminal, the registered mobile terminal number information, and the communication traffic information including the usage frequency information of the mobile terminal, Communication traffic information notifying means for notifying the mobile terminal.

[0013] With this, the base station broadcasts the line status information of the base station to the mobile terminal, and when the base station is congested according to the line state information, the base station in the vicinity of the mobile terminal. By notifying the communication traffic information of the station to the mobile terminal, it is possible to prompt the mobile terminal to select a base station in consideration of the communication traffic information.

In the wireless data communication system according to the present invention, the symbol period of the digital modulation is set to 100 μsec.
c] or more, and the base station and the mobile terminal each perform wireless data communication at different single frequencies using a carrier frequency at which the maximum Doppler frequency of the mobile terminal is 1/50 or less of the symbol rate. In, each base station is installed so that the radio wave coverage from a plurality of base stations each have an area overlapping a wide range, and in the base stations sharing the overlapping area, the carrier frequency of each base station is different. And the mobile terminal is provided with means for detecting a data communication traffic state of each base station in an overlapping area and selecting a base station having a small traffic amount.

Thus, the wireless data communication system is
In the above-described narrowband wireless data communication, the base station is arranged so that the radio wave coverage area has a wide overlapping area, and the mobile terminal determines the data communication traffic amount, which is the wireless data communication amount of each base station, in the overlapping area. Since it is possible to detect and select a base station with a small traffic amount among them, it is possible to avoid concentration of traffic from a mobile terminal to one base station.

In the mobile terminal according to the present invention, the symbol period of the digital modulation is set to 100 [μsec] or more, and the maximum Doppler frequency of the mobile terminal is 1/1 of the symbol rate.
In a wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies, respectively, using a carrier frequency of 50 or less, the radio wave coverage of a plurality of base stations may have an area that overlaps a wide range. And a mobile terminal in a wireless data communication system in which a base station sharing an overlapping area has a carrier frequency of each base station set to be different, and a data communication traffic state of each base station in the overlapping area. And a means for selecting a base station having a small traffic amount.

The mobile terminal according to the present invention receives, from a base station to be communicated with, information on the number of remaining packets of data being communicated and line status information including information on the number of reservations of another mobile terminal, and determines whether communication is possible. Line status determining means for determining the number of mobile terminals registered in the base station, and information on the number of registered mobile terminals, and communication traffic information including usage frequency information of the mobile terminals. And a base station detecting means for detecting a base station having a smaller data communication traffic amount.

Thus, the mobile terminal determines whether or not it is possible to communicate with the base station in the above-mentioned narrowband wireless data communication from the line state information broadcast from the base station with which the mobile terminal is to communicate, and if possible, performs communication. And if it is determined that it is impossible, it is possible to select a base station having a smaller data communication traffic amount from peripheral base stations based on communication traffic information broadcast from the same base station.

A base station according to the present invention is a base station that mediates wireless data communication with a mobile terminal according to claim 7, wherein the line status including the number of remaining packets of data being communicated to the mobile terminal and the number of reservations of the mobile terminal. Line status notifying means for notifying information, and communication traffic information for notifying the mobile terminal of communication traffic information including operation information of base stations around the mobile terminal, information of the number of registered mobile terminals, and usage frequency information of the mobile terminal. And a notifying means.

In the method for constructing a wireless data communication network according to the present invention, in the method for constructing a wireless data communication network in which a base station and a mobile terminal perform wireless data communication at different single frequencies, respectively, Reducing the overlapping area to reach the wider area with the minimum number of base stations, and setting the carrier frequency of each base station differently in the base station sharing the overlapping area; and In areas where there are many users, there is a step of adjusting the traffic capacity in each area by overlapping the radio wave coverage of base stations having different carrier frequencies in accordance with the number of users and the traffic volume.

Thus, the method of constructing a wireless data communication network reduces the overlapping area of the radio wave coverage from each base station, and allows the radio wave to reach a wider area with the minimum number of base stations. In the shared base station, the step of setting the carrier frequency of each base station to be different, and in an area where the traffic volume is large,
By overlapping the radio coverage of base stations with different carrier frequencies according to the number of users and the traffic volume, the traffic capacity can be reduced compared to the conventional technology that matches the characteristics of the region (the number of users in the region, traffic volume, etc.). Build a wireless data communication network that reduces waste.

The recording medium according to the present invention is a wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies, respectively, wherein the radio wave coverage of a plurality of base stations overlaps a wide range. A storage medium that is installed so as to have, and that records a program for a mobile terminal in a wireless data communication system in which a carrier frequency of each base station is set to be different in a base station sharing an overlapping area, Receiving, from the base station to be communicated in the overlapping area, line status information including information on the number of remaining packets of data being communicated and information on the number of reservations of other mobile terminals, and determining whether communication is possible; The operation information of the neighboring base stations, the number of registered mobile terminals, Based on the communication traffic information including the end of the usage frequency information, computer-readable recording medium storing a program for executing the steps of detecting more data communication traffic volume with less base stations.

A recording medium according to the present invention is a recording medium recording a program for a base station which mediates wireless data communication with a mobile terminal according to claim 3, wherein the remaining packet of data being communicated to the mobile terminal is recorded. Number, the step of broadcasting line state information including the number of reservations of the mobile terminal, the operation information of the base station around the mobile terminal, the information of the number of registered mobile terminals, the communication traffic information including the use frequency information of the mobile terminal, A step of notifying the mobile terminal, and a computer-readable recording medium recording a program for executing the step.

In the recording medium according to the present invention, the symbol period of the digital modulation is set to 100 [μsec] or more, and the maximum Doppler frequency of the mobile terminal is 1/1 / the symbol rate.
A wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies, respectively, using a carrier frequency of 50 or less, and a plurality of base stations are installed such that radio wave coverage ranges widely. A wireless data communication system which is installed so that the radio wave coverage of a plurality of base stations has an area which overlaps a wide area, and wherein the base station sharing the overlapping area has a different carrier frequency of each base station. A recording medium on which a program for a mobile terminal is recorded, wherein in the overlapping area, a base station to be communicated with from the base station, the line status including information on the number of remaining packets of data being communicated and information on the number of reservations of other mobile terminals. Receiving information,
Determining whether communication is possible, based on the operation information of the peripheral base station notified from the base station, the registered mobile terminal number information, and the communication traffic information including the use frequency information of the mobile terminal, Detecting a base station having a small data communication traffic amount; and a computer-readable recording medium recording a program for executing the steps.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described through embodiments of the present invention. However, the following embodiments do not limit the invention described in the claims, and all the combinations of the features described in the embodiments are necessary for solving the invention. Not necessarily. FIG. 1 is a block diagram showing a configuration of a base station and a physical area according to an embodiment of the present invention. In this figure, base station A
11, the base stations B and 12, and the base stations C and 13, respectively, have a physical area 11a and a physical area 1 having different carrier frequencies.
2a, a base station having a physical area 13a. As shown in the figure, the physical area 11a, the physical area 12a, and the physical area 13a overlap in a wide range. The mobile terminal 14 is a mobile terminal that exists in an area where all three of the physical area 11a, the physical area 12a, and the physical area 13a overlap, and has a single frequency different from that of one of the three base stations. Performs wireless data communication. In addition, it is assumed that the mobile terminal 15 and the mobile terminal 16 exist at the illustrated positions.

Here, base station A · 11 and base station B · 1
2. Broadcast information broadcast from each base station of the base stations C and 13 to each mobile terminal existing in each physical area will be described. For example, FIG. 2 shows an embodiment of broadcast information from the base station A 11 shown in FIG. 1 to each mobile terminal. As shown in FIG. 2, when the base station A.11 is communicating with the mobile terminals 15 and 16, each mobile terminal including the mobile terminal 14 in the physical area 11a of the base station A.11 is connected to the base station A.11. 11 informs the following information. In FIG. 2, if there are only two lines that can be used in the base station A · 11,
The base station A is in communication with the mobile terminal 15 and the mobile terminal 16.
11 is busy or in a congested state. In this case, the base station A / 11 analyzes the traffic information by analyzing a part of the line state information 18 of the packet being used by the mobile terminals 15 and 16. Then, the base station A · 11 transmits information on the number of remaining packets of the data during communication,
The channel state information 17A of the base station including the information on the number of reservations by other mobile terminals is included in the information packet 17 and broadcast to all mobile terminals within the area including the mobile terminal 14. Also,
The base station A · 11 transmits, for each base station, other station information 17B in which communication traffic information including operation information, registered mobile terminal number information, and mobile terminal use frequency information is grouped for each base station. , Stored in the information packet 17 and broadcast to all mobile terminals in the area including the mobile terminal 14.

Next, the internal configuration of the mobile terminal 14 will be described with reference to the drawings. FIG. 3 is a block diagram showing a schematic internal configuration of the mobile terminal 14 in the present embodiment. Reference numeral 21 denotes an antenna that receives a radio wave from a base station and transmits an electric signal from inside the mobile terminal 14. 22 is
A transmission / reception unit that demodulates a signal received from an antenna into a signal that can be processed inside the mobile terminal 14 and modulates an electric signal inside the mobile terminal 14 into a signal for transmission. 23
Is a control unit for controlling signals inside the mobile terminal 14. The line state determination unit 24 determines whether to communicate with the base station based on the line state information (remaining packet number information and reservation number information of another mobile terminal) of the base station broadcast from the base station. It is a line state determining means. Base station detection processing unit 2
5 detects a base station having a small data communication traffic amount based on communication traffic information (operating information of peripheral base stations, registered mobile terminal number information, mobile terminal use frequency information) broadcast from the base station. It is a base station detecting means.

Each of these processing units described above may be realized by dedicated hardware.
Each processing unit is a memory and a CPU (central processing unit).
And a program for realizing the function of each processing unit may be loaded into a memory and executed to realize the function. The memory may be a non-volatile memory such as a hard disk device, a magneto-optical disk device, or a flash memory, a read-only recording medium such as a CD-ROM, or a RAM (Random).
Access Memory), or a computer-readable and writable recording medium using a volatile memory such as an access memory or a combination thereof.

Next, as shown in FIG. 1, when the above-mentioned mobile terminal 14 exists in the overlapping area,
Will be described with reference to FIGS. 1, 3, and 4. FIG. FIG. 4 is a flowchart showing the operation of the mobile terminal 14 in the present embodiment. For example, if the mobile terminal 14 is the base station A · 11
When trying to start wireless data communication with the base station, first the line of the base station A.11 is busy or in a congested state (hereinafter referred to as BUS).
(Step S)
1). Next, the result of the detection is determined (step S2). Here, if it is not BUSY, the process proceeds to NO in step S2 to start communication with the base station A · 11 (step S3). B
If USY, it means YES in step S2 and base station A.1
For example, line status information including, for example, information on the number of remaining packets of data being communicated on the base station A · 11 broadcast from 1 is fetched, and the time until the end of the communication of the data being communicated is obtained from the information on the number of remaining packets. Is larger than the allowable delay time (step S4). In addition to the remaining packet number information, the base station A.1
The reservation number information for 1 is also suitable for use in determining the line state.

Here, if the processing time of the number of remaining packets (the time until the end of the call) is smaller than the allowable delay time (NO in step S4), the process stands by while the base station A.11 is BUSY (step S5). YES). Then, when the base station A · 11 is no longer BUSY (step S5)
NO) starts communication with the base station A · 11 (step S6).

If the processing time of the number of remaining packets (the time until the end of the call) is longer than the permissible delay time (YES in step S4), the operation information on the latest peripheral base station notified from the base station A · 11 is transmitted. From the communication traffic information including the registered number of mobile terminals and the usage frequency information of the mobile terminals, it detects which of the base stations B12 and C13 has smaller communication traffic (step S7). Next, by switching to the detected carrier frequency of the base station, the line is switched from the base station A · 11 to the detected base station (step S8). Next, the line state of the switching destination base station is detected to check whether communication can be started (step S9).

Further, the judgment value in the detection of the base station in step S7 is not limited to the communication traffic amount as described above. For example, weighting factors W1, W2, and W3 are respectively assigned to operation information (for example, the number of used lines), the number of registered mobile terminals (the number of registrations), and the usage frequency (operation rate) of the mobile terminals, for the peripheral base station. The expression for multiplication is shown below. Base station state judgment value = W1 × Registration number + W2 × Operation rate + W3 × Number of used lines The judgment of step S7 may be made based on the base station state judgment value by this formula. By using the above equation, by changing the weighting coefficients W1, W2, and W3, it is possible to adjust which of the number of registrations, the operating rate, and the number of used lines should be weighted when judging the state of the base station. Can be done.

Next, in a wireless data communication system in which the physical areas of a plurality of base stations overlap in a wide range, when a plurality of mobile terminals are concentrated in the physical area of a single base station, the mobile station and the mobile station may not move. FIG. 5 is a schematic diagram showing a state of wireless data communication between terminals. The base station A 41 is a base station having a physical area 41a, and similarly the base station B 4
2. The base station C 43 also has a physical area 42a and a physical area 43a, respectively, and has a wide overlapping area as shown in the figure. It is assumed that each base station can simultaneously perform wireless data communication with up to five mobile terminals. Further, 15 mobile terminals are scattered in each of the physical area 41a, the physical area 42a, and the physical area 43a. Then, as shown in the figure, 12 of the 15 mobile terminals exist in the physical area 42a.

In the case of the base station arrangement and the distribution of mobile terminals as described above, if the physical area has almost no overlap as in the prior art, the base station B · 42 becomes congested,
Since the maximum number of mobile terminals that can simultaneously perform wireless data communication is five, other mobile terminals cannot perform communication.
However, as shown in the present embodiment, since the overlapping area is widened, the physical area 42 of the base station B
Physical area 41a, physical area 43a overlapping with a
In, the mobile terminal can perform wireless data communication with the base stations A and 41 and the base stations C and 43, respectively.

Next, one embodiment of a method for constructing a wireless data communication network is shown in FIG. As shown in FIG. 6, generally, the distribution density of mobile terminals is biased. In addition, the bias is often stationary, for example, the distribution density is high in urban areas and low in mountainous areas. According to the configuration method of the wireless data communication network according to the present embodiment, first, base stations are arranged so that overlapping areas are reduced, such as the physical area 1A, the physical area 2A, and the physical area 3A in the figure. By doing so, a wider area can be covered by the sum of the three physical areas. Next, the area where the density of mobile terminals is high is assigned to the physical area 4
A base station is arranged so as to be covered by A. By doing so, the traffic capacity of the area can be increased. With the above method, a wireless data communication network corresponding to the distribution density of mobile terminals can be constructed. Further, since a situation in which a high-performance base station is arranged in an area where the distribution density of mobile terminals is low unlike the conventional case does not occur, the cost can be reduced. Also, it is simpler to deal with a change in distribution density than in the past.

Further, in this embodiment, it is not necessary to use a high-performance base station having a high traffic capacity as compared with the related art.
In areas where the distribution density of mobile terminals is high, the physical areas of base stations with medium traffic capacity may be superimposed. In areas where the distribution density of mobile terminals is low, low-cost base stations with low traffic capacity are used. Such a construction method can be executed, and thus the degree of freedom in constructing the system is high.

Further, in the above, a wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies is described in Japanese Patent Application No. 11-139311. In a narrow-band wireless data communication system, the same implementation is possible by arrangement of base stations and the like. This narrow-band wireless data communication system has a symbol period of digital modulation of 10
This is a wireless data communication system for performing wireless data communication between a base station and a mobile terminal using a carrier frequency at which the mobile terminal has a maximum Doppler frequency equal to or less than 0 [μsec] and a maximum Doppler frequency of 1/50 or less of the symbol rate.

In the above wireless data communication system, since the physical area per base station is wide, the overlapping range can be widened. As a result, it is easy to adjust the area of the overlapping portion. Also, because of the narrow band, it is possible to increase the number of different carrier frequencies set in the base station sharing the overlapping area, that is, it is possible to increase the number of overlapping areas, so that a more effective wireless data communication network can be constructed. Becomes

Further, a program for realizing the function of a processing unit that performs various processes in the broadcast information creation processing in each base station and the broadcast information processing in each mobile terminal in FIG. 1 is stored in a computer-readable recording medium. Each process may be performed by recording and causing a computer system to read and execute the program recorded on the recording medium. The “computer system” here means
It includes hardware such as an OS and peripheral devices. The “computer system” also includes a homepage providing environment (or display environment) if a WWW system is used. The “computer-readable recording medium” refers to a portable medium such as a floppy disk, a magneto-optical disk, a ROM, a CD-ROM, and a storage device such as a hard disk built in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) inside 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. , For a certain period of time.
Further, the above 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 a 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.
Further, the above program may be a program 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 described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments and includes a design and the like within a range not departing from the gist of the present invention.

[0040]

As described above, according to the wireless data communication system of the present invention, each base station is installed such that the radio wave coverage from a plurality of base stations has an area that overlaps a wide range. Further, in the base stations sharing the overlapping area, the carrier frequency of each base station is set to be different. Further, the mobile terminal detects a data communication traffic state of each base station in the overlapping area. Further, by selecting a base station having a small traffic amount, concentration of traffic from a mobile terminal to one base station is avoided. As described above, there is an effect that the possibility that a congestion state occurs is reduced.

Further, the mobile terminal according to the present invention detects a data communication traffic amount, which is a wireless data communication amount of each base station, in an area where radio waves from a plurality of base stations overlap. In addition, since a base station having a small traffic amount can be selected among them, a mobile terminal can perform wireless data communication while avoiding a congested base station. As described above, there is an effect that a congestion state is less likely to occur in the entire system.

Further, the communication terminal according to the present invention determines whether or not communication with the base station is possible based on the line state information broadcast from the base station with which communication is to be performed. Further, if possible, communication is performed. If it is determined that communication is not possible, a base station having a smaller data communication traffic amount is selected from peripheral base stations based on communication traffic information broadcast from the same base station. As described above, there is an effect that a delay in communication due to an increase in the amount of communication traffic hardly occurs.

The base station according to the present invention broadcasts the line status information of the base station to the mobile terminal. Further, when the base station is in a congested state according to the line state information, the base station notifies the mobile terminal of communication traffic information of base stations near the mobile terminal. As described above, the mobile terminal can be prompted to select a base station in consideration of the communication traffic information.
Conventionally, a communication request may be issued many times to a congested base station, thereby accelerating the congestion state. However, even in the congested state, the mobile terminal may transfer the line to another base station. Since the switching is performed, there is an effect that the congestion state can be easily released.

In the wireless data communication network construction method according to the present invention, the overlapping area of the radio wave coverage from each base station is reduced, and the radio wave reaches a wider area with the minimum number of base stations. Next, in the base stations sharing the overlapping area, the carrier frequency of each base station is set to be different. Next, in an area with a large traffic volume, radio wave coverage of base stations having different carrier frequencies is overlapped according to the number of users and the traffic volume. As described above, it is possible to construct a wireless data communication network in which waste of traffic capacity is reduced as compared with the related art, which is suitable for characteristics such as the number of users in the region and traffic volume, and the effect of reducing the cost of installing base stations. There is.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a base station and a physical area according to an embodiment of the present invention.

FIG. 2 is a diagram showing broadcast information from a base station A · 11 to each mobile terminal according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic internal configuration of a mobile terminal 14 according to an embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the mobile terminal 14 according to the embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a state of wireless data communication between a base station and a mobile terminal according to the present invention.

FIG. 6 is a diagram showing one embodiment of a method for constructing a wireless data communication network according to the present invention.

FIG. 7 is a diagram showing overlapping radio wave coverage in a conventional communication system between a base station arrangement and mobile terminals.

[Explanation of symbols]

 Reference Signs List 11 base station A 11a physical area 12 base station B 12a physical area 13 base station C 13a physical area 14, 15, 16 mobile terminal 17 information packet 17a line state information 17b other station information 18 user data packet 18a line state information 21 antenna 22 Transmitter / receiver 23 Control unit 24 Line status determination unit 25 Base station detection processing unit 41 Base station A 41a Physical area 42 Base station B 42a Physical area 43 Base station C 43a Physical area 1A, 2A, 3A, 4A Physical area 51a Cell (1) ) 51b Physical Area 52a Cell (2) 52b Physical Area 53a Cell (3) 53b Physical Area 54 Base Station A 55 Base Station B 56 Base Station C 57 Overlapping Area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuyoshi Tari 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Inside Mitsubishi Mobile Real Estate Mobile Business Development Center (72) Inventor Takao Yokoshima 1- Kitabukurocho, Omiya City, Saitama Prefecture 297 Mitsubishi Materials Corporation Mobile Business Development Center (72) Inventor Kenzo Nakamura 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Mobile Business Development Center (72) Inventor Hiroyuki Unoki Omiya City, Saitama Prefecture 1-297 Kitabukurocho Mitsubishi Material Corporation Mobile Business Development Center F term (reference) 5K033 AA04 CB01 DA01 DA19 DB20 EA07 5K067 AA12 BB21 DD42 DD43 EE02 EE10 EE56 JJ73

Claims (12)

[Claims] In a wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies, each base station has an area where radio waves from a plurality of base stations overlap in a wide range. And the base station sharing the overlapping area is set so that the carrier frequency of each base station is different, and the mobile terminal detects the data communication traffic state of each base station in the overlapping area. And a means for selecting a base station having a small traffic amount. 2. A wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies, respectively, wherein the base stations and the mobile terminals are installed such that radio wave coverages of a plurality of base stations have an area that overlaps a wide range. And a mobile terminal in a wireless data communication system in which a carrier frequency of each base station is set to be different in a base station sharing an overlapping area, wherein a data communication traffic state of each base station is detected in the overlapping area. And a means for selecting a base station having a small traffic amount. 3. The mobile terminal transmits, in the overlapping area, line status information including information on the number of remaining packets of data being communicated and information on the number of reservations of another mobile terminal, which are broadcast from a base station to be communicated with. Receiving, line state determining means for determining whether communication is possible, and communication traffic information including peripheral base station operation information, registered mobile terminal number information, and mobile terminal usage frequency information reported from the base station. 3. The mobile terminal according to claim 2, further comprising: a base station detecting means for detecting a base station having a smaller data communication traffic amount. 4. A base station for mediating wireless data communication with a mobile terminal according to claim 3, wherein the line for notifying the mobile terminal of line status information including the number of remaining packets of data being communicated and the number of reservations of the mobile terminal. Operating information of the state notifying means and the peripheral base station of the mobile terminal, information on the number of registered mobile terminals, communication traffic information including usage frequency information of the mobile terminal, communication traffic information notifying means for notifying the mobile terminal, A base station comprising: 5. The symbol period of digital modulation is set to 100
[μsec] or more, and the base station and the mobile terminal perform wireless data communication at different single frequencies using a carrier wave frequency at which the maximum Doppler frequency of the mobile terminal is 1/50 or less of the symbol rate. In the system, each base station is installed such that radio wave coverage from a plurality of base stations has an area where the base stations share the overlapping area, and carrier frequencies of the base stations are different in base stations sharing the overlapping area. The mobile data communication system further comprises means for detecting a data communication traffic state of each base station in the overlapping area and selecting a base station having a small traffic amount. 6. The digital modulation symbol period is set to 100.
[μsec] or more, and the base station and the mobile terminal perform wireless data communication at different single frequencies using a carrier wave frequency at which the maximum Doppler frequency of the mobile terminal is 1/50 or less of the symbol rate. In a system, a radio data communication system is installed such that radio wave coverage of a plurality of base stations has an area where the base stations share an overlapping area, and carrier frequencies of the respective base stations are different in base stations sharing the overlapping area. The mobile terminal according to claim 1, further comprising: means for detecting a data communication traffic state of each base station in the overlapping area and selecting a base station having a small traffic amount. 7. The mobile terminal receives line state information including information on the number of remaining packets of data being communicated and information on the number of reservations of another mobile terminal from a base station to communicate with, and determines whether communication is possible. Line state determining means, based on communication traffic information including mobile station operation information, mobile terminal number information registered, and mobile terminal usage frequency information reported from the base station. ,
7. The mobile terminal according to claim 6, further comprising: a base station detecting unit that detects a base station having a smaller data communication traffic amount. 8. A base station for mediating wireless data communication with a mobile terminal according to claim 7, wherein the line for notifying the mobile terminal of line status information including the number of remaining packets of data being communicated and the number of reservations of the mobile terminal. State notifying means and communication traffic information notifying means for notifying the mobile terminal of communication information including operation information of the base station in the vicinity of the mobile terminal, registered mobile terminal number information, and usage frequency information of the mobile terminal. A base station comprising: 9. A method for constructing a wireless data communication network in which a base station and a mobile terminal perform wireless data communication at different single frequencies, wherein an overlapping area of radio wave coverage from each base station is reduced, and a minimum base station is provided. Reaching radio waves to a wider area by number; setting base station carrier frequencies to be different in base stations sharing the overlapping area; and setting the number of users in a high traffic area. Adjusting the traffic capacity in each region by overlapping the radio wave coverage of base stations having different carrier frequencies in accordance with the traffic volume. 10. A wireless data communication system in which a base station and a mobile terminal perform wireless data communication at different single frequencies, respectively, wherein the base stations and the mobile terminals are installed such that the radio wave coverage of a plurality of base stations has an area that overlaps a wide range. ,And,
A recording medium storing a program for a mobile terminal in a wireless data communication system in which a carrier frequency of each base station is set to be different in a base station sharing an overlapping area, and communication is to be performed in the overlapping area from now on From the base station, receiving the remaining packet number information of the data in communication, the line state information including the reservation number information of the other mobile terminal, and determining whether communication is possible, and of the peripheral base station notified from the base station Detecting a base station having a smaller data communication traffic amount based on the operation information, the registered mobile terminal number information, and the communication traffic information including the usage frequency information of the mobile terminal; and a program for executing A computer-readable recording medium on which is recorded. 11. A recording medium on which a program for a base station which mediates wireless data communication with a mobile terminal according to claim 3 is recorded, the number of remaining packets of data being communicated to the mobile terminal, the reservation of the mobile terminal. Notifying the mobile terminal of operation information of peripheral base stations of the mobile terminal, information of the number of registered mobile terminals, and communication traffic information including usage frequency information of the mobile terminal. And a computer-readable recording medium on which a program for executing the program is recorded. 12. The digital modulation symbol period is set to 100.
[μsec] or more, the base station and the mobile terminal perform wireless data communication at different single frequencies, respectively, using a carrier frequency at which the maximum Doppler frequency of the mobile terminal is 1/50 or less of the symbol rate. A wireless data communication system in which base stations are installed such that radio wave coverage ranges overlap over a wide range, wherein a base station is installed such that radio wave coverages of a plurality of base stations have an area that overlaps over a wide range, and the base stations share an overlapping area. A recording medium recording a program for a mobile terminal in a wireless data communication system in which a carrier frequency of each base station is set to be different in a station, wherein in the overlapping area, a base station that is about to communicate from the base station is communicating. Information on the number of remaining packets of data,
Receiving line state information including reservation number information of another mobile terminal, and determining whether communication is possible; operating information of peripheral base stations broadcast from the base station; registered mobile terminal number information; Detecting a base station with a smaller data communication traffic amount based on communication traffic information including usage frequency information of a mobile terminal; and a computer-readable recording medium recording a program for executing the steps.