Radio communication system for reducing interference of other communication system using approach frequency band

TECHNICAL FIELD The present invention relates to a radio communication system and channel allocation method for providing communication services for mobile terminal devices, and a communication control device in the system.

2. Description of the Related Art In a known simplified portable phone called PHS (Personal Handset System), the mobile terminal device has a smaller output (1(W)) compared with the current digital cellular phone system, which makes the mobile terminal device compatible with The communication range of the base station is limited. In addition, the scheme adopted in the existing PHS can realize data communication, which is faster than the current digital cellular phone system (32KBPS to 64KBPS).

On the other hand, W-CDMA (Wideband-Code Division Multiple Access) has been proposed as a solution for realizing fast data communication (such as 64KBPS to 384KBPS).

The W-CDMA uses a 2G bandwidth radio signal (uplink: 1.92 to 1.98GHz, downlink: 2.11 to 2.17GHz>. In addition, the above-mentioned PHS uses a 1.9GHz bandwidth radio signal (12.89365 to 1.91945GHz).

However, these radio communication systems use close frequencies, so in order to avoid interference between them, guard bands are provided between the frequency bands used by the corresponding radio communication systems. A guard band of approximately 5 MHz is provided between the upper limit frequency of the frequency band used by PHS and the lower limit frequency of the frequency band used by W-CDMA.

In addition, the corresponding radio communication system uses a filter that reduces components outside a predetermined frequency band (channel width). To avoid interference between these radio communication systems.

However, depending on the positional relationship between mobile terminal devices and base stations such as PHS and W-CDMA, there are cases where components outside a predetermined frequency band can be sufficiently reduced in one radio communication system, but cannot be communicated in another radio. Fully reduced on the system.

Specifically, the signal band of W-CDMA is about 5MHz, so the so-called false-sufficiency or noise is generated in a wide frequency range and extends beyond the guard band, so they may interfere with the PHS side.

02120424.1 In addition, the transmission energy of w-CDMA is quite larger than that of PHS, so this situation occurs. The receiver on the PHS side has so-called receiver blockage, which reduces the receiving sensitivity.

In order to avoid interference with the PHS, the performance may be improved by the W-CDMA side of the filter, at a predetermined frequency to suppress spurious components or noise band occurs. However, the transmission energy difference between PHS and W-CDMA is very large, so if the components outside the predetermined frequency band are suppressed to the extent that they do not affect the PHS side under any conditions, a filter on the W-CDMA side is required Has particularly strict blocking characteristics (attenuation rate in the blocking area). The filter that realizes this characteristic has a complicated structure using many elements, and this requires large energy consumption and size. Therefore, it is particularly difficult to use this filter in a mobile terminal device because the mobile terminal device has high requirements for small size and low power consumption.

SUMMARY OF THE INVENTION The object of the present invention is to provide a channel allocation method, a communication control device, and a radio communication system that can help reduce interference generated by other communication systems that use radio signals in a near frequency band. According to one aspect of the present invention, a channel allocation method is provided. A method for allocating a channel for communication between a mobile terminal device and a second radio base station, the second base station using a second frequency band close to the first frequency band used by the first radio base station, and the channel allocation method includes the steps To: detect the first distance between the second radio base station and the first radio base station; when the first distance is less than the first threshold, detect the second distance between the second radio base station and the mobile terminal device; and when the second distance When it is less than the second threshold, the frequency in the second frequency band that is far from the first frequency band is allocated to the communication between the second radio base station and the mobile terminal device.

According to another aspect of the present invention, there is provided a channel allocation method for allocating channels to communication between a mobile terminal device and a second radio base station, the second base station using the first radio base station used with the first radio base station. If the frequency band is close to the second frequency band, the channel allocation method includes the steps of: detecting the distance between the first radio base station and the mobile terminal device; and when the distance is less than a predetermined threshold, moving away from the first frequency band in the second frequency band The frequency of is allocated to the communication between the second radio base station and the mobile terminal device.

According to another aspect of the present invention, a communication control device is provided for controlling mobile

02120424.1 The channel used for communication between the first terminal device and the second radio base station. The second radio base station uses a second frequency band close to the first frequency band used by the first radio base station. The communication control device includes: detecting the second radio base station and A first distance detecting unit for the first distance between the first radio base station; when the first distance is less than the first threshold, a second distance detecting unit for detecting the second distance between the second radio base station and the mobile terminal device; and when the first distance When the second distance is less than the second threshold, the frequency that is far from the first frequency band in the second frequency band is allocated to the channel allocation unit for communication between the second radio base station and the mobile terminal device.

According to another aspect of the present invention, there is provided a communication control device for controlling a channel used for communication between a mobile terminal device and a second radio base station, wherein the second radio base station uses the second radio base station used with the first radio base station. One frequency band is close to the second frequency band. The communication control device includes: a distance detecting unit for detecting the distance between the first radio base station and the mobile terminal device; and a channel allocating unit, when the distance is less than a predetermined threshold, the channel allocating unit for switching in the second frequency band A channel far from the first frequency band is allocated to the communication between the second radio base station and the mobile terminal device.

According to another aspect of the present invention, there is provided a channel allocation method for allocating a channel to a communication between a mobile terminal device and a second radio base station, wherein the second radio base station uses the one used with the first radio base station. The first frequency band is close to the second frequency band, the channel allocation method includes the steps of: controlling the received energy of a signal from a mobile terminal device to a constant value at the second radio base station; according to the mobile terminal communicating with the second radio base station Obtain the channel allocation ratio for communication between the second radio base station and one mobile terminal device by the total number of devices and the total received energy of signals other than one mobile terminal device; and obtain channel switching as a switching channel criterion based on the allocation ratio Distance: Detect the distance between the second radio base station and the mobile terminal device, and when the distance is greater than the channel switching distance, allocate the channel in the second frequency band far from the frequency of the first frequency band to the second radio base station and the mobile terminal device Communication between.

According to another aspect of the present invention, there is provided a communication control device for controlling a channel used for communication between a mobile terminal device and a second radio base station, wherein the second radio base station uses the same second radio base station as the first radio base station. A frequency band close to a second frequency band, the communication control device includes a receiving energy control unit, which is used to transfer data from a second radio base station to a

02120424.1 The received energy of the signal of the first mobile terminal device is controlled to a constant value; the allocation ratio calculation unit is based on the total number of mobile terminal devices communicating with the second radio base station and the total reception of signals other than i mobile terminal devices Energy, obtain the channel allocation ratio for communication between the second radio base station and a mobile terminal device; a distance calculation unit, which obtains the channel switching distance as a criterion for switching channels based on the allocation ratio; and a distance detection unit, which detects the first The distance between the two radio base stations and one mobile terminal device, and the channel allocation unit. When the distance is greater than the channel switching distance, the unit allocates channels in the second frequency band far from the frequency of the first frequency band to the second radio base station and the mobile terminal Communication between devices.

From the following description in conjunction with the accompanying drawings, other features and advantages of the present invention will become apparent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural diagram of a radio communication system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing the structure of a radio control device in the radio communication system of FIG. 1. FIG.

FIG. 3 is an exemplary channel view used in the radio communication system of FIG. 1. FIG.

Fig. 4 is a flowchart of an exemplary channel allocation process used in the radio communication system of Fig. 1.

Fig. 5 is a flowchart of another exemplary channel allocation process used in the radio communication system of Fig. 1.

Fig. 6 is a structural diagram of a radio communication system according to a second embodiment of the present invention.

Fig. 7 is a block diagram showing the structure of a radio control device in the radio communication system of Fig. 6;

Fig. 8 is an exemplary channel view adopted in the radio communication system of Fig. 6.

Fig. 9 is a view of the channel switching distance adopted in the radio communication system of Fig. 6.

Fig. 10 is a flowchart of an exemplary channel allocation process in the radio communication system of Fig. 6.

FIG. Π is a flowchart of an exemplary channel switching process employed in the radio communication system of FIG. 6.

Fig. 12 is an exemplary structural diagram of the radio communication system according to the first embodiment of the present invention.

Fig. 13 is another exemplary configuration diagram of the radio communication system according to the first embodiment of the present invention.

02120424.1 Fig. 14 is another exemplary structural diagram of the radio communication system according to the first embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the radio communication system of the present invention will be described in detail below with reference to FIGS. 1 to 5.

The present invention is used for channel allocation, communication control, etc. in a communication system, where the communication system works in the presence of another communication system that uses a close frequency.

As shown in FIG. 1, the radio communication system 20 provides communication services by using radio signals in a frequency band close to that of the radio communication system 10, wherein the radio communication system 10 has a set of base stations M to 1h for providing communication services and uses The base station port 4 provides the mobile terminal device 12 of the communication service.

The radio communication system 10 is, for example, a PHS (Personal Handset System), in which a 1.9 GHz frequency band (1.89365 to 1.91945 GHz) is used for communication between the base station port to 1L. and the mobile terminal device 12. In addition, the radio communication system 10 utilizes a TDMA (Time Division Multiple Access) scheme to realize communication between a base station and a group of mobile terminal devices. For channels that communicate through this TDMA scheme, each channel uses a frequency band of 300 MHz.

For base stations M to 11..., corresponding areas (cells) 1 to 13 are allocated_ηβIn addition, each base station to is connected to the radio communication control unit 14 through a communication line.

Through the radio communication control unit 14, the mobile terminal device 12 involved in one of the corresponding cells to 13 and each base station 11 provide access services to the Internet, a wired communication network, another radio communication network, and the like.

In addition, the radio communication system 20 has a set of base stations 21 for providing communication services 21. Mobile terminal devices 22 for using the communication services provided by the base stations 2h to 21 and implemented in the base stations 2X to 21», and mobile terminals The radio control unit 24 controls the radio communication between the devices 22.

The radio communication system 20 is a W-CDMA (Wideband-Code Division Multiple Access) scheme handheld phone system, which uses the 2GHz frequency band (uplink: 1.92 to 1.98GHz; downlink: 2. to 2.17GHz) Radio signals are used for communication between the base stations 2h to 21 and the mobile terminal device 22. In addition, the radio communication system 20 uses CDMA (Code Division Multiple Access)

02120424.1 The first plan is to use a set of channels for communication, and each channel uses a 5MHz frequency band. A set of such frequency bands is provided to each service provider of the radio communication system.

It should be noted that the transmission output of the mobile terminal device 12 of the radio communication system 10 is approximately 10W, which is particularly smaller than the transmission output of the mobile terminal device 22 of the radio communication system 20.

The base station 21 is assigned to a corresponding area (cell) 23 to 23. In addition, each of the base stations 21, to 21 · is connected to the radio communication control unit 24 through a wired or radio communication line · through the radio communication control unit 24, in one of the corresponding cells 2 to 23n, the mobile terminal device 22 involved Each base station 21' to 21 provides access services such as the Internet, a wired communication network, and another radio communication network.

At least the cells from spots 4M to 11n corresponding to the aforementioned base stations 4M to 11n-partially overlap with the cells 23] corresponding to the base station 2h.

In addition, in FIG. 1, for simplicity, only one mobile terminal device 12 and one mobile terminal device 22 are shown, but the number of mobile terminal devices 12 and 22 is not limited, and a group of mobile terminal devices 12 and/ Or a group of mobile terminal devices 22.

The radio communication control unit 24 has the structure shown in FIG. 2 and has a memory 25, a base station control unit 26, a switching unit 27, a radio channel control unit 28, and a call processing control unit 29 therein. The memory 25 is used to store information (location information) indicating the location of the mobile terminal device 22 of each user and information (base station data) such as the location of the base station 11 of the radio communication system 10; the base station control unit 26 is used to control the base station 11 The operation of the ratio; the switching unit 27 is used to control the communication between the base station land to 21 and the network 30 or other equipment; the radio channel control unit 28 is used to control (uplink and downlink) in the base station 21 to 21 and mobile The channel used for communication between the terminal devices 22; and the call processing control unit 29 is used to implement the mobile terminal device 22 or call interruption control from the mobile terminal device 22.

The memory 25 stores a terminal position table 25a and a base station information table 25b. The terminal position table 25a is used to indicate the position of the mobile terminal device 22, which uses the radio communication system 20; the base station information table 25b is used to indicate radio In-use locations and channels of base stations lh to lln in the communication system 10. It should be noted that the memory 25 also stores an instruction base station

02120424.1 p.

The position of 21 inverted 21» and the parameters corresponding to the inverted mouth of the base station 11, where the base station 11 inverted 11n has a cell that overlaps with each base station 21 inverted 21" cell 23 inverted 2N overlapped cell 13 inverted IX» stored in the terminal position table 25a The location information of the mobile terminal device 22 is information indicating the location of the mobile terminal device 22 and is derived from the mobile terminal device 22. The mobile terminal device 22 obtains itself based on the strength of the radio signal from a group of base stations 2h to 2h The positions and the positions of these base stations 21 up to 2h, and these information are provided to the radio communication control unit 24 together with the identification information (user ID) assigned to the mobile terminal device 22. The radio communication control unit 26 and the radio channel control unit 28 pass through the base station control unit 26 and the radio channel control unit 28. The communication control unit 24 stores the provided identification information and location information in the terminal location table 25a.

Optionally, a position detection unit called GPS (Global Positioning System) may be provided for the mobile terminal device 22, and the position detected by the position detection unit is provided to the radio communication control unit 24 similarly to the above-mentioned manner. . The information indicating the location from the mobile terminal device 22 is provided to 24 at predetermined time intervals, so that the location of the mobile terminal device 22 stored in the terminal location table 25a can be updated periodically.

The radio channel control unit 28 is connected to the radio communication control unit 14 of the radio communication system 10 through the network 40. In addition, the radio channel control unit 28 is connected to a receiver 50 for receiving radio information from base stations to 11 constituting the radio communication system 10. According to the radio signals received from each base station to lh The receiver 50 detects the cell ID, location, etc., and provides these information to the radio channel control unit 28. The radio channel control unit 28 stores the provided cell ID, location, etc. in the base station information table 25b as base station data.

It should be noted that, in order to detect the locations of base stations 1h to 1h, the receiver 50 can only detect the cellular IDs from the base station port to 11", and the radio channel control unit 28 can obtain instructions from the radio communication control unit 14 via the network 40 for the base stations 1k to 1h. Information such as the location of the base station to lh corresponds to these cell IDs. For the radio channel control unit 28, it is also possible to obtain only the information indicating the location of the base stations 11' to H» from the radio communication unit 14.

As shown in FIG. 3, the frequency band used for the downlink (transmission from the base station to the mobile terminal device) in the radio communication system 20 is separated from the frequency band used by PHS, but the frequency band used for the uplink (transmission from the mobile terminal device) is separated from the frequency band used by PHS. To the base station) of the lower limit frequency of the frequency band and the frequency band used by PHS

02120424.1 The upper limit frequency is approaching. It should be noted that FIG. 3 compares the transmission energy of the mobile terminal device 12 and the mobile terminal device 22, and the two energies at base stations M to 1 are different from the signal strengths from the mobile terminal devices 12 and 22.

As shown in FIG. 3, the radio communication system 10 is designed to appropriately select one of the channels in the above-mentioned 1.9 GHz frequency band, and is used for communication between the base station 11 and the mobile terminal device 12. In addition, the radio communication system 20 is designed to appropriately select channels among the channels (chAk, chA2, chA3 -, chAk-1, chAk) having a bandwidth of 5 lffiz, and serve as the base station 2h to 21" and the mobile terminal device 22. Inter-communication.

In addition, as shown in FIG. 3, a frequency band (guard band) not used by the two radio communication systems is provided between the frequency bands used by the radio communication system 10 and the radio communication system 20. The guard band has a bandwidth of 5MHZ.

Moreover, as described above, the transmission output of the mobile terminal device 12 of the radio communication system 10 is very small compared to the transmission output of the mobile terminal device 22 of the radio communication system 20, so there is such a case even when on the radio communication system 20 side. When the components outside the above-mentioned frequency band are weakened to a sufficient degree, relatively large noise will also be generated on the side of the radio communication system 10.

In addition, because the transmission energy of the mobile terminal device 22 is particularly larger than the transmission energy of the mobile terminal device 12, such a situation occurs. Depending on the conditions, the so-called receiver blockage occurs from the base station to Ih, which reduces the receiving sensitivity. .

Therefore, the radio communication system 20 is designed to control the channel used for the uplink from the mobile terminal device 22 to the base station 21, thereby reducing the influence on the radio communication system 10 side.

According to the distance between the mobile terminal device 22 and each base station 11, and the frequency difference between the channel used by the mobile terminal device 22 and the channel used by each base station 1h to 1h, the data from the mobile terminal device 22 The intensity (energy) of the out-of-band component will change accordingly, where the component is observed as noise at the base station 11 and 11".

More specifically, when the distance between the mobile terminal device 22 and each base station 11 becomes larger, the intensity of the out-of-band component from the mobile terminal device 22 decreases due to spatial propagation loss. In addition, when the frequency difference between the channels used by the mobile terminal device 22 and the base stations 1h to 1h becomes larger, the intensity of components outside the frequency band observed as noise at the base station becomes smaller. This is caused by the reduced intensity of false components such as higher harmonic components and intermodulation components. These

02120424.1 The first component is generated due to the nonlinearity of the amplifier of the radio communication device when they are far away from the carrier frequency.

Therefore, based on the terminal location table 25a and base station information table 25b stored in the above-mentioned memory 25, and based on the separately managed uplink channel frequency from the mobile terminal device 22, the radio channel control unit 28 is designed to obtain mobile The distance between the terminal device 22 and each base station 1h to 1h, and the channel frequency difference between each base station 1 to 11" and the uplink from the mobile terminal device 22. In addition, the radio channel control unit 28 judges that it detects Whether the distance and the frequency difference are at a level that can cause interference, and the channel allocation processing for uplink from the mobile terminal device 22 is executed based on the judgment result.

At this time, when the base stations M to 1h are located within a predetermined distance from the base station 2h, there is a situation in which it can determine whether the interference is generated by using the distance to the mobile terminal device 22, which is assumed to be the base station M to lh is obtained by taking an approximate value at the position of the base station 21*.

In addition, for each of the base stations 1h to 11" and the uplink from the mobile terminal device 22, the channel frequency is different, because the channel width of the radio communication system 20 is particularly larger than the channel width of the radio communication system 10, so this is the case That is, it can be judged whether the interference is generated by considering only the uplink channel starting from the mobile terminal device 22, without considering the channel used by each base station 11, to ih.

By simplifying the parameters for determining whether interference is generated in this way, the burden of the channel allocation processing in the radio communication control unit 24 can be reduced.

As shown in FIG. 4, in this channel allocation process, in step S1, when a call from the mobile terminal device 22 involving the base station 211 occurs, by referring to the base station information table 25b in the memory 25 (step S2), the radio channel The control unit 28 checks whether some base stations of the radio communication system 10 exist in the cell 23] of the base station 2h. When the base station is 11 down 11_BWhen none of the cells are located in the cell 2, the process proceeds to step S3, where any of the above channels (chAl, chA2-----) is allocated as an uplink line from the mobile terminal device 22, and the process is completed Channel allocation processing.

On the other hand, when any base station 11 of the radio communication system 10 exists in the cell 23ι of the base station 21, the process proceeds to step S4, in which it is checked whether the information indicating the position of the corresponding base station 11 is recorded in the base station information table. 25b. When the base station 11 is instructed to invert the 4 position

If the second information of 02120424.1 is recorded in the base station information table 25b, the process proceeds to step S7.

When the information indicating the position of the corresponding base station 11 is not recorded in the base station information table 25b, through the network 40, the radio channel control unit 28 obtains from the radio communication control unit 14 information indicating that the corresponding base station 11 is inverted (step S5) , And store the information in the base station information table 25b (step S6), and the process proceeds to step S7.

It should be noted that in step S5, through the network 40, the information indicating the positions of the corresponding base stations 1h to 1h is not obtained from the radio communication control unit 14, according to the signals received from the base stations 11i to 11n through the receiver 50 Cell ID and other information in the cell ID, you can get the location of the base station 1 1. To I . In addition, the processing of these steps S4 to S6 is executed for each base station 1b to 1h in the cell 2F. In this way, before step S7 is executed, a state is recognized, that is, in this state, information indicating the port-to-port positions of all base stations in the cell 2 is stored in the base station information table 25b.

In step S7, from the position of the base station 11 in the base station information table 25b and the separately stored information indicating the position of the base station 2h, the radio channel control unit 28 obtains the base station 21 and each base station 11 in the cell 23]. The distance between inverted Ik (DU)₀Next, in step S8, the radio channel control unit 28 compares the distance (D11) between the base station 2h and each base station Π to lh in the cell 2F with a predetermined distance (dis), when the base station 2R and the cell 23 When all the distances between the base stations lh and lln in the base station are greater than or equal to the predetermined distance (dis), the process proceeds to step S3, where any channel is allocated to the uplink starting from the mobile terminal device 22, and the channel allocation process is completed .

On the other hand, when the distance (dll) between the base station 2A and any one of the base stations 1h to 11n in the cell 23' is less than the predetermined distance (dis), the process proceeds to step S9, in which the radio channel control unit 28 checks the mobile terminal Whether the location information of the device 22 is stored in the terminal location table 25a. When the location information of the mobile terminal device 22 is stored in the terminal location table 25a, the process proceeds to step S12, otherwise the process proceeds to step S10.

In the latter case, the radio channel control unit 28 obtains the position of the mobile terminal device 22 (step S10) and stores it in the terminal position table 25a (step S11), and then the process proceeds to step S12.

In step S12, the radio channel control unit 28 calculates the base station 2h and the mobile terminal device

02120424.1 p.

The distance between 22 (D22).

Then, in step S13 and subsequent steps, the radio channel control unit 28 selects the channel allocated to the uplink from the mobile terminal device 22.

Here, it is assumed that lWsWIWk, d22minWd22max, where s and z are arbitrary integers, and these numbers are set to make it easier to set the channel by dividing the channel used by the radio communication system 20 into three regions. In addition, d22max is the distance between the base station 2h and the mobile terminal device 22 under the condition of no interference to those base station ports to 11", because the frequency band channel used by the radio communication system 10 (ChAl in Fig. 3 above) is used as the slave When the mobile terminal device 22 starts the uplink channel, the distance to the base station 2h is less than the predetermined distance (dis), and the d22max is obtained through experiments.

First, in step S13, the radio channel control unit 28 judges whether the distance (d22) between the Sri Lanka base station 2h and the mobile terminal device 22 is greater than a predetermined threshold (d22max).

When the distance 322 between the base station 2h and the mobile terminal device 22) is greater than the predetermined threshold (d22max), it can be considered that those base stations whose distance (dll) from the base station 2h is less than the predetermined distance (dis) will not pass from the port to port. The mobile terminal device 22 receives interference on the uplink channel started. Therefore, in step S14, through the base station control unit 26, the radio channel control unit 28 allocates the available channels in the channels CchAl to chAs) as the uplink channels from the mobile terminal device 22, where the available channels are close to those of the radio For the frequency band used by the communication system 10, the channel allocation process is completed. The allocated channel is notified to the base station control unit 26, and the transmission from the mobile terminal device 22 is started.

On the other hand, when the distance (d22) between the base station and the mobile terminal device 22 is less than or equal to the predetermined threshold ((122)), the radio channel control unit 28 judges the difference between the base station 2A and the mobile terminal device 22 obtained in step S12 Is the distance (D22) less than or equal to the predetermined threshold (d22niin).

When the distance (D22) between the base station 2h and the mobile terminal device 22 is less than or equal to the predetermined threshold (d22min), if the proximity radio communication system 10 uses the channel allocation of the frequency band as the uplink channel from the mobile terminal device 22, then It can be considered that those base stations 11 whose distance (D11) to the base station 2h is less than the predetermined distance (dis) will receive interference. Therefore, in step S16, through the base station control unit 26, the radio channel control unit 28

02120424.1 The available channel allocation in (chA1 to chAk) is the uplink channel from the mobile terminal device 22, and the available channel is far away from the frequency band used by the radio communication system 10, and the channel allocation process is completed. The allocated channel is notified to the base station control unit 26, and the transmission from the mobile terminal device 22 is started.

On the other hand, when the conditions of step S13 and step S15 are not satisfied, that is, when the distance (D22) between the base station 2h and the mobile terminal device 22 is greater than d22min and less than or equal to d22max, the process proceeds to step S17 , Wherein through the base station control unit 26, the radio channel control unit 28 allocates available channels in the channels (chAs+1 to chAl-1) as uplink channels starting from the mobile terminal device 22, wherein the available channels are other than In step S14 and step S16, channels other than those are allocated, and the channel allocation process is completed. The allocated channel is notified to the base station control unit 26, and the transmission from the mobile terminal device 22 is started.

It should be noted that when the above-mentioned d22max and d22min are the same, the above-mentioned s and 1 are set to s=1, so the channel used for the uplink from the mobile terminal device 22 is divided into two. In this case, any one of the conditions of step S13 and step S15 described above is always satisfied, so the process of step S17 is not executed.

In addition, for each mobile terminal device 22, the aforementioned channel allocation processing from step S1 to step S17 in FIG. 4 is executed. In this way, even when a group of mobile terminal devices 22 exists, an appropriate channel can be set for the uplink.

As described above, in the radio communication system 10, when the base station to exists at a predetermined distance (DH) from the base station 2h, if the distance between the base station 2h and the mobile terminal device 22 is less than or equal to the predetermined distance (d22ndn ), the channel far from the frequency band used by the radio communication system 10 is allocated as an uplink channel from the mobile terminal device 22.

Therefore, in the radio communication system 20, it is easy to reduce the interference generated by the base stations 1h to 1h of the radio communication system 10.

In addition, in the radio communication system 20, the filter is not required to have strict characteristics of suppressing components outside the predetermined frequency band, so there is no need to unnecessarily complicate the structure of the mobile terminal device 22 or the base stations 1h to 1h. Therefore, the size of these devices can be reduced, and the energy consumption can be reduced. It is also possible to avoid unnecessary increases in costs.

It should be noted that the above description refers to the allocation of channels to a mobile terminal device 22

02120424.1 The first uplink to a base station 2h to 21·, but there are also uplink lines used for transmission from a mobile terminal device 22 to a group of base stations 21] to 21. In this case, for each uplink line, the channel allocation process from step S1 to step S17 of FIG. 4 described above will be performed.

It should also be noted that the above description refers to the situation that when base stations 1h to 1L exist within a predetermined distance (dis) from base station 2h, according to the distance between base station 2h and mobile terminal device 22, control is used for slave The mobile terminal device 22 starts the allocation of the uplink channel. By performing processing based on the distance between the base station 2 h and the mobile terminal device 22 in this way, the processing load becomes smaller compared with the case where the distance between each base station 11 and the mobile terminal device 22 is obtained.

However, from the standpoint of improving the space utilization of radio signals, it is better to obtain the distance between each base station 11 to 11. and the mobile terminal device 22, and based on these distances, control the distance from the mobile terminal device 22 The channel allocation used for the uplink line.

As shown in FIG. 5, in this channel allocation process, when in step S21, it appears that the base station 21_（When calling from the mobile terminal device 22, by referring to the base station information table 25b in the memory 25, the radio channel control unit 28 checks whether some of the base stations 1h to 11 of the radio communication system 10 exist in the cell 2 of the base station 211 (Step 22). When the base station 11" is not located in the cell 2", the process proceeds to step S23, where any of the above-mentioned channels (chA1, chA2, -----) is allocated as the slave mobile terminal device 22 in this step. At the beginning of the uplink frequency, the channel allocation process is completed.

On the other hand, when some of the base stations to 1h of the radio communication system 10 are located in the cell 23ι, the process proceeds to step S24, in which it is checked whether the location information indicating the corresponding base stations 1h to 11" is recorded in the base station information table. 25b. When the position information indicating these base stations to 11... is recorded in the base station information table 25b, the process proceeds to step S27.

When the position information indicating the corresponding base station port to 11 ". is not recorded in the base station information table 25b, the radio channel control unit 28 obtains the information indicating the position of the corresponding base station lk to lh from the radio communication control unit 14 through the network 40 (step S25) , And store the information in the base station information table 25b, and then the process proceeds to step S27.

It should be noted that in step S25, the information indicating the positions of the corresponding base stations 1h to 11" is obtained from the radio communication control unit 14 without going through the network 40, and the information may be received through the receiver 50.

02120424.1 Cell Ids or other information in the first arrival signal to obtain the location of the base station. In addition, for each base station 11 in the cell 23', the processes of these steps S24 and S26 are executed. In this manner, before step S27 is performed, a state is identified that indicates that the position information of all base stations lh to lh in the cell 23. is stored in the base station information table 25b, which is the same as that shown in FIG. 4 above. The channel allocation process is similar.

In step S27, the radio channel control unit 28 checks whether the location information of the mobile terminal device 22 is stored in the terminal location table 25a. When the location information of the mobile terminal device 22 is stored in the terminal location table 25a, the process proceeds to step S30_o When the location information of the mobile terminal device 22 is not stored in the terminal location table 25a, the radio channel control unit 28 requests the location information of the mobile terminal device 22 (step S28), and stores the response location information in the terminal location table 25a ( Step 29), and then the process proceeds to step S30. The request for the location information of the mobile terminal device 22 can be directly submitted to the mobile terminal device 22 through the base station control unit 26, or to the management server and other devices through the network 30, wherein the management server and other devices are used to manage each mobile terminal device 22 s position.

In step S30, when obtaining the positions of the base stations M to 1k and the mobile terminal device 22, the radio channel control unit 28 obtains the distance between each of the base stations 11] to 11" and the mobile terminal device 22 (D33).

After obtaining the distance (D33) between each base station lk and ll. and the mobile terminal device 22 in this way, in step S31 and the following steps, the radio channel control unit 28 selects and allocates to the mobile terminal device 22 Uplink channel starting at 22.

Here, assuming 1 WuWvWk and d33niinWd33max, where u and ν are arbitrary integers, these numbers are set so as to make it easier to set the channel by dividing the channel used by the radio communication system 20 into three regions. In addition, d33max is the distance between each base station M and the mobile terminal device 22 in the following cases, that is, even when the closest to the frequency band used by the radio communication system 10 (chA1 in FIG. 3 above) is used as the slave mobile terminal device When the uplink channel starts at 22, it will not interfere with the base stations 11' to ll". The distance d33max is obtained through experiments₀ First, in step S31, the radio channel control unit 28 determines whether the distance (D33) between the base stations 1h to 11 and the mobile terminal device 22 obtained in step S30 is greater than a predetermined threshold.

02120424.1 The largest (d33max).

When all the distances (D33) between the base station 11 and the mobile terminal device 22 are greater than the predetermined threshold (d33max), it can be considered that all the base stations 1h to 11 in the cell 23' of the base station 2h will be No interference is received through the uplink channel from the mobile terminal device 22. Therefore, in step S32, the radio channel control unit 28 allocates the available channels in the channels (chA1 to chAu) as the frequency bands used for the uplink from the mobile terminal device 22, which are the same as those used in the radio communication system 10. The frequency band is close, so the channel allocation process is completed. The allocated channel is notified to the base station control unit 26, and the uplink transmission from the mobile terminal device 22 is started.

On the other hand, when the distance (D33) between some base station 11h and the mobile terminal device 22 is less than or equal to the predetermined threshold value Cd33max), the radio channel control unit 28 judges the arrival and movement of the base station 1h obtained in step S30. Whether certain distances between the terminal devices 22 are less than or equal to a predetermined threshold (d33min).

When any distance (D33) between some base stations 1h to 1h and the mobile terminal device 22 is less than or equal to the predetermined threshold (d33min), at the same time, if the channel of the frequency band used by the radio communication system W is close to the mobile terminal device 22 When the initial uplink channel is allocated, it can be considered that the base station whose distance (D33) to the mobile terminal device 22 is less than the predetermined distance (d33inin) will receive interference from the mobile terminal device through the channel for 1 h. Therefore, in step S34, the radio channel control unit 28 allocates the available channel in the channels (chAv to chAk) as the uplink channel from the mobile terminal device 22, wherein the available channel is far from the frequency band adopted by the radio communication system 10 , And the channel allocation process is completed. The allocated channel is notified to the base station control unit 26, and the uplink transmission from the mobile terminal device 22 is started.

On the other hand, when the above two conditions of step S31 and step S33 are not satisfied, that is, when all the distances between the base station 11 and the mobile terminal device 22 are greater than d33min, at the same time the base station 1h to 1h and the mobile terminal device 22 When some distance (D33) is less than or equal to d33max, the process proceeds to step S35. In this step, the radio channel control unit 28 allocates such available channels as uplink channels from the mobile terminal device 22, where the The channel is a channel other than those allocated by the above step S32 and step S34 (chAu+1

02120424.1 to the available channels in chAv-1), then the channel allocation process is completed. The allocated channel is notified to the base station control unit 26, and the uplink transmission from the mobile terminal device 22 is started.

In addition, for each mobile terminal device 22, the channel allocation processing from step S21 to step S35 in FIG. 5 is respectively executed. In this manner, when a group of mobile terminal devices 22 exists, an appropriate channel for the uplink is established.

As described above, in the channel allocation process of Fig. 5 similar to the process of Fig. 4 described above, if certain distances between the base stations 1h to 11n and the mobile terminal device 22 are less than or equal to the predetermined distance (d33min), then the radio communication system The channel whose frequency band is far away from the adopted 10 is allocated as the uplink channel from the mobile terminal device 22.

Therefore, in this channel allocation process, the interference caused by the base station 11 of the radio communication system 10 can be easily reduced.

In addition, in this channel allocation process, according to the distance from each base station to 11n and the mobile terminal device 22, the allocation of the uplink channel from the mobile terminal device 22 can be performed. Therefore, it is possible to realize the channel allocation indicating the actual utilization state of the radio electric signal, and thus can contribute to providing the space utilization rate of the radio electric signal.

It should be noted that the above description refers to the situation where the frequency band used by the radio communication system 10 is lower than the frequency band used by the radio communication system 20, but this relationship can be reversed. In this case, the channels to be allocated in steps S14 and S16 in FIG. 4 are switched, and the channels to be allocated in steps S32 and S34 in FIG. 5 are switched at the same time.

It should also be noted that in the above description, the present invention is described from the perspective of reducing the interference caused by the radio communication system 20 to the radio communication system 10. The radio communication system 20 causes interference.

For example, Figure 1 above refers to the situation where the transmission output of the base station 11 of the radio communication system 10 to 11» is particularly smaller than the transmission output of the base station 21 to 21m of the radio communication system 20, and the cellular station to 13 "contains In the cell 23], there are also cases where the transmission output of the base station 21 to 25 is smaller than the transmission output of the base station port to 11". In this case, honeycomb 23. to 23m should be included in honeycomb 13_tInside.

It should also be noted that false components such as high harmonic components, intermodulation components, etc. are also removed from the base station lh

02120424.1 Numbers to 11... and generated from the mobile terminal device 12 of the radio communication system 10. These components are caused by the non-linearity of the amplifier.

When these false components from the radio communication system 10 are generated in the frequency band used by the radio communication system 20 as the uplink frequency, interference to the radio communication system 20 is generated.

Therefore, under this condition, the radio communication control unit 14 on the side of the radio communication system 10 is similar to that of the above-mentioned radio communication control unit 24. Or similar channel allocation processing in Figure 5.

In this way, it is possible to easily detect the state of potential interference from the radio communication system 10 to the radio communication system 20 in the cellular 1 and at the same time to easily reduce the interference caused by the radio communication system 10 to the radio communication system 20. .

According to a channel allocation method of the first embodiment, the distance between the first radio base station and the second radio base station is detected, and when the detected distance is less than the first threshold, the distance between the second radio base station and the mobile terminal device is detected , And when the detected distance is less than the second threshold, a frequency channel far from the first frequency band is allocated to the communication between the second radio base station and the mobile terminal device.

In this way, it is easy to reduce the interference to the first radio base station caused by the communication between the second radio base station and the mobile terminal device.

In addition, by realizing such channel allocation, it is possible to relax the characteristic requirements of the filter of the mobile terminal device. Therefore, it contributes to the reduction of the size of the mobile terminal device and the reduction of energy consumption.

In addition, according to another channel allocation method of the first embodiment, the distance between the first radio base station and the mobile terminal device is detected, and when the detected distance is less than a predetermined threshold, a frequency channel far from the first frequency band is allocated to the second radio Communication between base station and mobile terminal device.

In this way, it is easy to reduce the interference to the first radio base station caused by the communication between the second radio base station and the mobile terminal device.

In addition, by realizing such channel allocation, it is possible to relax the requirements on the characteristics of the filter of the mobile terminal device. Therefore, it contributes to the reduction of the size of the mobile terminal device and the reduction of energy consumption.

In addition, according to the distance between the first radio base station and the mobile terminal device, it is also possible to realize the channel allocation indicating the actual utilization state of the radio signal, so that it can contribute to the provision of radio

02120424.1 The space utilization of the first electrical signal.

Hereinafter, the second embodiment of the radio communication system of the present invention will be described in detail with reference to FIGS. 6 to 14.

In the above-mentioned first embodiment, under the condition that the two radio communication systems adopt close frequency bands, when the coverage area of the base station of the first radio communication system contains a group of base stations of the other radio communication system, two of the communication systems Using a close frequency band, control the base station of the first radio communication system based on the distance between the base station of the first radio communication system and the base station of another radio communication system and the distance between the base station of the first radio communication system and the mobile terminal device The channel frequency used for communication with the mobile terminal device can thus reduce the interference to another radio communication system and at the same time avoid the complexity of the device structure.

However, in this channel allocation method, because there are many base stations of another radio communication system, and the distance between these base stations is calculated for channel control, the base station cell of the (first) radio communication system contains another radio communication system. Under the condition of the base station, proper channel allocation becomes difficult. As a result, it is possible to cause interference to another radio communication system. The second embodiment is a channel allocation method to solve this problem.

The present invention is used for channel allocation, communication control, etc. in a communication system operating under the following conditions. For example, as shown in FIG. 6, the condition is that there is another communication system that uses a close frequency.

Another radio communication system 110 has a set of base stations 111. to llh for providing communication services and mobile terminal devices 112 that utilize the communication services provided by the base stations 11k to llh.

The radio communication system 110 is, for example, a PHS (Personal Handset System), which uses the 1.9 GHz frequency band (1.89365 to 1.91945 GHz) for communication between the base stations 11 h to 111" and the mobile terminal device 112. In addition, the 110 uses TDMA (Time Division Multiple Access) scheme to realize communication between a base station and a group of mobile terminal devices. For the channels that communicate through this TDMA scheme, for example, each channel uses a frequency band of 300KHZ.

For the base station 14, a corresponding area (cellular) 113 is allocated. In addition, each base station 11h to 11k is connected through a communication line.

In the mobile terminal device 112 involved in one of the corresponding cellular networks to 113·., each base station 11h to 11h provides connection services for the Internet, a wired communication network, another radio communication network, and the like.

02120424.1 In addition, the radio communication system 120 has a set of base stations 121. to 121. for providing communication services, mobile terminal devices 122 for using the communication services provided by the base stations to 12L., and implementations at the base stations 121 to 121. and 122. The radio control unit 124 for radio communication control.

In the radio communication system 120, a set of channels with different frequencies are provided to realize communication between a base station 12ι and a set of mobile terminal devices 122, and at the same time a 2GHz band signal just above the 1.9GHz band is used, Used for communication between the base station 121 and the mobile terminal device 122. TDD (Time Division Duplex) can also be realized by dividing a frequency channel into uplink and downlink time slots. It is also possible to divide a frequency channel into two or more time slots to provide a group of logical channels, which are used for communication using a group of mobile terminal devices 122.

For base stations 121] to 121m, corresponding areas (cells) 123ι to 123m are allocated_oIn addition, each of the base stations 121 to 121 is connected to the radio communication control unit 124 through a wired or radio communication line.

Through the radio communication control unit 124, for the mobile terminal device 122 within a corresponding cell 123' to 123m, each base station 12h to 125 provides access services to the Internet, a wired communication network, another radio communication network, etc. (in the back Simply called communication services).

Here, the radio communication system 110 adopts a radio signal having a smaller transmission energy than the radio communication system 120. The transmission output of the mobile terminal device 112 of the radio communication system 110 is about 10W, which is particularly smaller than the transmission output of the mobile terminal device 122 of the radio communication system 120. In addition, the transmission energy of the base stations 1 to 111n is smaller than the transmission energy of the base stations 121. to 12 such.

Therefore, the cells 11 to 113» corresponding to the base stations 111 to 111n are smaller than the cells 123 to 123, corresponding to the base stations 12k to 121m, and a group of cells 113 are arranged in the cell 123,.

It should be noted that the number of mobile terminal devices 112 and 122 is not limited to those shown in FIG. 6, but any number of mobile terminal devices 112 and 122 can be used. The mobile terminal devices 112 and 122 are allocated to base stations 11h to 11 h and the base station 121, to the channel range of each of 121m.

02120424.1 The first radio communication control unit 124 has the structure shown in FIG. 7 and has a memory 125, a base station control unit 126, a switching unit 127, a radio channel control unit 128, and a call processing control unit 129. The memory 125 is used to store information (location information) indicating the location of the mobile terminal device 122 of each user; the base station control unit 126 is used to control the operation of the base stations 12h to 12L; the switching unit 127 is used to control the base stations 12h to 121 and the network or Communication between other devices; the radio channel control unit 128 is used to control the channel used for communication between the base station 121 and the mobile terminal device 122; and the call processing control unit 129 is used to implement the mobile terminal device 122 or from the mobile terminal device 122 The call interruption control of the device 122.

The memory 125 stores a terminal position table 125a and a base station information table. The terminal position table 125a is used to indicate the position of the mobile terminal device 122 and the currently used channel group (chA, chB), etc., and the mobile terminal device 122 uses the radio communication system 20. ; The base station information table is used to indicate the positions and channels in use at the base stations 12h to 121.

The position information of each mobile terminal device 122 stored in the terminal position table 125a is expressed as a combination of X coordinates and Y coordinates (Xi, Yi (1=1. 2, ------X)), where the coordinates The combination is located in a service providing area for providing communication services related to the mobile terminal device 122. Based on the radio signal strength from a group of base stations 121 to 121m and the positions of these base stations 12h to 121m, the mobile terminal device 122 obtains its own position and associates this information with the identification information assigned to the mobile terminal device 122 (user ID uniquely corresponds to For a single mobile terminal device 122, for example, Ui (i=K 2-X)) one channel is provided to the radio communication control unit 124. The provided identification information and location information are stored in the terminal location table 125a through the base station control unit 126 and the radio channel control unit 12 & the radio communication control unit 124.

Optionally, a position detection unit called GPS (Global Positioning System) may be provided for the mobile terminal device 122, and the position detected by the position detection unit is sent to the radio communication control unit 124 similarly to the above-mentioned manner. . The information indicating the location from the mobile terminal device 122 is provided to 124 at predetermined time intervals, so that the location of the mobile terminal device 122 stored in the terminal location table 125a can be updated periodically.

Next, in radio communication, it is best to use the necessary minimum transmission energy to avoid interference and mixing. On the other hand, in order to safely receive the signal from the mobile terminal device 122 at the base station 121, it is necessary to make the signal-to-interference ratio (SIR) greater than a predetermined value. Therefore, the radio communication

02120424.1 The first letter system 120 is designed to control the transmission energy value of the mobile terminal device 122 at an appropriate value.

According to the energy and noise energy observed at the receiving base station, the SIR is different. Noise energy is obtained by measuring the energy of components other than those actually used for communication.

In addition, depending on the spatial propagation loss of the radio signal, the energy observed at the receiving base station is different, so it varies with the distance between the transmitting base station and the receiving base station. When the mobile terminal device 122 is the transmitting base station and the base station 12h is the receiving base station, the noise energy is the same for both so that the energy received by the base station 12h is constant. When the distance is larger, the transmission energy of the mobile terminal device 122 needs to be larger, and when the distance between the mobile terminal device 122 and the base station 12h is smaller, the transmission energy of the mobile terminal device 122 is smaller.

Therefore, in this radio communication system 120, the transmission energy (Pi (1=1. 2, ------, X)) of the mobile terminal device 122 is controlled to the constant SIR of the signal from 122, and the mobile terminal device 122 communicates with each base station 12R to 12 plus. When the base station 12L issues a command to control energy to 122, it performs transmission energy control of the mobile terminal device 122. According to the command, the mobile terminal device 122 controls the transmission energy. In this way, when the distance D1 is large, the mobile terminal device 122 The transmission energy of 122 is controlled to be larger, and when the distance D1 is smaller, the energy of the mobile terminal device 122 is controlled to be smaller.

As described above, the radio communication systems 110 and 120 use close frequencies. In addition, as described above, the transmission output of the mobile terminal device 112 of the radio communication system is smaller than the transmission output of the mobile terminal device 122 of the radio communication system 120. Therefore, there are cases in which when on the side of the radio communication system 120, When the components outside the predetermined frequency band are attenuated to a sufficient degree, greater noise is generated to the radio communication system 110.

In addition, because the transmission energy of the mobile terminal device 122 is greater than the transmission energy of the mobile terminal device 112, there are cases where, depending on the conditions, the so-called receiver blockage occurs between the base station llh to the llln receiver, which reduces the reference sensitivity. degree.

More specifically, according to the transmission energy of the mobile terminal device 122 and the distance between the mobile terminal device 122 and the base station llh to Uh, the interference energy in the vicinity of the base station 121' varies, but the base station 1U receives it. , Generated by a signal from the mobile terminal device 122. As described above, when the distance Di between the mobile terminal device 122 and the base station 121' is large, the mobile

02120424.1 The transmission energy of the first terminal device 122 is controlled to be large, and when the distance Di is small, the energy is small. Therefore, when the distance Di between the mobile terminal device 122 and the base station is large, the interference energy received by the base station 111 and 11h from the mobile terminal device 122 in the vicinity of the base station 12k is large, and when the distance Di is small, the energy is small.

In addition, the interference generated by the radio signal from the mobile terminal device 122 can be received by the base station 11h in the vicinity of the base station 12h, and the interference can use the channel frequency and the base station 111 used for communication between the mobile terminal device 122 and the base station 12h. Reverse 14 uses the channel frequency to be corrected. When these frequencies are close, the interference energy is greater, and when these frequencies differ greatly, the interference energy is smaller.

As shown in FIG. 8, the radio communication system 120 uses a 2 GHz frequency band, which is just larger than the frequency band adopted by the radio communication system 10 (1.9 GHz frequency band). In addition, as shown in FIG. 8, the frequency band (guard band) not used by the two radio communication systems is set between the frequency bands used by the radio communication system 110 and the radio communication system 120. The guard band has a bandwidth of 5MHZ. It should be noted that, in order to better understand the frequency relationship, FIG. 8 shows the spectral intensities of the radio communication system 110 and the radio communication system 120 in different numerical ranges.

When the frequency used between the mobile terminal device 122 and the base station 12h is close to the frequency band used by the radio communication system 110, the interference energy received by the base station 111 in the vicinity of the base station 1 becomes larger. Conversely, when the frequency used between the mobile terminal device 122 and the base station 12h is far from the frequency band used by the radio communication system 110, the interference energy received by the base station 111. near the base station 12h becomes smaller. This is due to the fact that the intensity of false components such as higher harmonic components and intermodulation components becomes lower when they are far away from the carrier. These false components are generated by the non-linearity of the amplifier of the radio communication device.

As described above, depending on the distance between the mobile terminal device 122 and the base station 121], the interference energy received by the base station 111 and 111. also varies. Therefore, the radio communication system 120 is designed such that when the distance between the mobile terminal device 122 and the base station 12h is large, a frequency channel far from the frequency band used by the radio communication system 110 is allocated to the communication between the mobile terminal device 122 and the base station. When the distance between the mobile terminal device 122 and the base station 12h is small, the frequency channel of the frequency band adopted by the proximity radio communication system 110 is allocated to the communication between the mobile terminal device 122 and the base station 12A.

02120424.1 First, the above-mentioned channel allocation can be realized by determining the channel frequency used by each mobile terminal device 122 and controlling the channel allocation by the radio channel control unit 128.

In order to reduce the burden of control, the channels used by the radio communication system 120 can also be divided into a group close to the frequency band used by the radio communication system 110 and a group far away from the frequency band used by the radio communication system 110, so they are allocated in each group (channel group ). More specifically, as shown in FIG. 8 above, the P channel used in the radio communication system 120 is divided into channel groups (ChA (chA1, chA2, -----, chAk)) and the channel group (ChB(chBl, chB2,

.........Ί ............................ ........ 1 I ,/ /Ο In order to reduce the control burden, a method is also provided in which the number (N) of all mobile terminal devices 122 that communicate with the base station 12h is measured, and the base station 211 occupies the channel allocation control target mobile device 122 for communication, and also measures The interference energy (Iall) of the signal of the transmission signal other than the channel allocation control target mobile terminal device 122, based on the interference energy (Iall) and the above-mentioned number N, the channel allocation ratio of the channel group ChA and the channel group ChB ( αΐ, α2), as shown in Figure 9, based on these channel allocation ratios, a predetermined threshold (channel switching distance Dre) is established. When the distance Di between the mobile terminal device 122 and the base station 12h is less than the switching distance Dre, the channel group is allocated The channels in ChA, or when the distance Di is less than the switching distance Dre, the channels in the channel group ChB are allocated.

The above-mentioned channel allocation processing is implemented according to the method program in FIG. 10, so when a call involving the base station 12 winter occurs in the mobile terminal device 122, the processing starts from step S101 in FIG. It should be noted that in the following description, for the purpose of simplification, only the case of a call involving one base station 12h is described, but there are also cases where a mobile terminal device 122 is used when a communication scheme using a set of frequencies is used. A call involving a group of base stations 121 is generated.

In the terminal location table 125a in the memory 125 described above, the mobile terminal devices 122 in the cells 12 to 123m of the base stations 12h to 121m and the channels used by each mobile terminal device 122 are stored separately. According to the table, the radio channel control unit 128 obtains the number (N) of mobile terminal devices 122 in the cell 123 of the base station 121, (step S101)_o When the number N of mobile terminal devices 122 in the cell 123] is obtained, the radio channel control unit 128 measures the total (interference energy) of signal reception energy, where the signal is

02120424.1 Signals other than those of the mobile terminal device 122 that originated the call (step S102)_oThe interference energy Iall thus measured is provided to the radio channel control unit 128 via the base station control unit 126.

When the interference energy Iall is provided, based on the number N of mobile terminal devices 122 and the interference energy Iall obtained above, the radio channel control unit 128 obtains the allocation ratio (αΐ, α2) of the channel groups ChA and ChB at the base station 12 (Step S103)_oHere, al and α2 are positive values, and the relationship is α1+α2=1_β When N and Iall take specific values, these ratios α 1 and α 2 can be determined according to a predetermined function, which is used to optimize the capacity of the radio communication system 110 and the radio communication system 120.

This function can be obtained by properly setting the communication conditions and using computer simulation. In addition, the function can be established by an empirical formula obtained by using actual communication.

When the obtained allocation ratios α 1 and α 2 for the channel groups CHA and CHB are obtained, the radio channel control unit 128 determines the distance (double-channel switching distance) for realizing channel switching (step S104)_o The channel switching distance Dre satisfies Dre²:R²-Dre²=a 1: the value of the α2 relationship, where R is the radius of the honeycomb 123, as shown in FIG. 9 above.

In Figure 9 above, within the cell 12, these two areas can be obtained, where the distance to the base station 121. is less than or equal to the channel switching distance Dre, and where the distance to the base station is greater than the channel switching distance Dre and less than or equal to The area of the honeycomb radius R, these two areas are expressed as η spit cloud and π R²-Sunn Dre% Therefore, the area ratio of these areas is DrelF-Dre. The channels in the channel groups CHA and CHB are respectively allocated to the communication between the mobile terminal device 122 and the base station 121' in these areas, and the channel allocation ratio of the mobile terminal device 122 in the cell 123] becomes chaotic. , By setting the channel switching distance Dre that satisfies the above relationship, the channel allocation ratios for the channel groups ChA and ChB in the cell 123' can be α 1 and α 2, respectively.

After obtaining the channel switching distance Dre, the radio channel control unit 128 checks whether the location information of the mobile terminal device 122 where the call occurs is registered in the terminal location table 125a (step S105). When registered, the radio channel control unit 128 obtains the base station 121' and the distance Di between the mobile terminal device 122 and register it in the terminal position table 125a (step

02120424.1 p.

S108).

When the position information of the mobile terminal device 122 is not registered in the terminal position table 125a (step S105), the radio channel control unit 128 requests to obtain the position information of the mobile terminal device 122 (step S106), and the obtained position of the mobile terminal device 122 The information is registered in the terminal location table 125a, and the process of step S108 is executed.

When the distance Di between the base station 1211 and the mobile terminal device 122 is obtained, the radio channel control unit 128 compares the distance with the channel switching distance Dre obtained above (step S109)_o When the distance Di between the base station 121 and the mobile terminal device 122 is less than or equal to the channel switching distance Dre, since the transmission energy of the mobile terminal device 122 is controlled as described above, the transmission energy is relatively low. Therefore, in this case, even if the frequency is close to the channel of the frequency band adopted by the radio communication system 110, when the channel in the channel group CHA is allocated to the communication between the mobile terminal device 122 and the base station 12h, the base station near the base station 12h The interference energy observed at 111 inverted 111. will be relatively low, and the interference effect due to the transmission signal of the mobile terminal device 122 will also be relatively low.

Therefore, when the distance Di between the base station 121] and the mobile terminal device 122 is less than or equal to the channel switching distance Dre, the radio channel control unit 128 allocates the available channels in the channel group CHA to the mobile terminal device 122 and the base station 12h. Inter-communication (step S110)_o On the other hand, when the distance Di between the base station 12A and the mobile terminal device 122 is greater than the channel switching distance Dre, the transmission energy of the mobile terminal device 122 is relatively high. Therefore, in this case, if the frequency is close to the channel of the frequency band adopted by the radio communication system 110, for example, when the channel in the channel group CHA is allocated to the communication between the mobile terminal device 122 and the base station 12A, the channel near the base station 121] The interference energy observed at the base station 111 to 111. will be relatively large, and the interference effect caused by the transmission signal of the mobile terminal device 122 will also be relatively large.

Therefore, when the distance Di between the base station 12h and the mobile terminal device 122 is greater than the channel switching distance Dre, the radio channel control unit 128 allocates the available channels in the channel group Cffi to the mobile terminal device 122 and the base station 121]. Communication (step S111).

In the radio communication system 120, channel allocation can be realized through the foregoing, and the influence of interference on the radio communication system 110 can be reduced.

02120424.1 First, when the mobile terminal device 122 moves, the distance Di between the base station 12h and the mobile terminal device 122 also changes. The radio channel control unit 128 periodically obtains the location information of the mobile terminal device 122, and updates the location information in the terminal location table 125a. Optionally, when the mobile terminal device 122 itself is detected to move, the mobile terminal device 122 transmits the new location information to the radio channel control unit 128. After receiving the information, the radio channel control unit 128 checks the terminal location table 125a. The location information in is updated.

In such a case, due to the movement of the mobile terminal device 122, the relationship between the distance between the base station 12A and the mobile terminal device 122 and the channel switching distance Dre also changes. In this case, it is necessary to switch the channel used for communication between the mobile terminal device 122 and the base station 12h.

FIG. 11 shows a procedure of such channel switching processing. When the mobile terminal device 122 stored in the terminal position table 125a changes with the movement of the mobile terminal device 122, the processing starts from step S121 in FIG. 11.

First, from the updated new location information of the mobile terminal device 122, the radio channel control unit 128 obtains the current distance Di' between the mobile terminal device 122 and the base station 12h (step S121)_o Next, the radio channel control unit 128 obtains the number N of mobile terminal devices 122 in the cell 123' of the base station 12 (step S122), and obtains the interference energy Iall at the base station 12h (step S122).

5123), obtain the allocation ratios α 1 and α 2 of channel groups CHA and CHB from N and Iall (step

5124), and obtain the channel switching distance Dre similarly to steps S101 to S104 in FIG. 10 (step S125) ₀ After obtaining the channel switching distance Dre, the radio channel control unit 128 compares the above-obtained distance Di' between the base station 12h and the mobile terminal device 122 with the channel switching distance Dre (step S126).

When the distance Di' between the base station 12R and the mobile terminal device 122 is less than or equal to the channel switching distance Dre, the radio channel control unit 128 checks whether the currently allocated channel is in the channel of the channel group CHB (step S127), if it is in the channel If the channel is in the group CHB, the radio channel control unit 128 controls to switch to an available channel in the channel group OIA (step S128). If the currently allocated channel is a channel in the component group CHA, then the channel is reserved

02120424.1 No change. In this manner, it is recognized that the channels in the channel group CHA are allocated to the communication state between the mobile terminal device 122 and the base station 12h.

On the other hand, when the distance Di between the base station 12h and the mobile terminal device 122 is greater than the channel switching distance Dre, the radio channel control unit 128 checks whether the currently allocated channel is in the channel group CHA (step S129), if it is If the channel is in the channel group CHA, the radio channel control unit 128 controls to switch to an available channel in the channel group CHB (step S130)_oIf the currently allocated channel is a channel in the component group CHB, then the channel remains unchanged. In this manner, it is recognized that the channels in the channel group CHB are allocated to the state of communication between the mobile terminal device 122 and the base station 12h.

When the above processing is completed, the radio channel control unit 128 updates the distance Di in the terminal position table 125a to the current distance Di obtained above. Through this switching process, even when the mobile terminal device 122 moves, the mobile terminal The channel between the device 122 and the base station 12h can be properly maintained.

In the first embodiment described above, as shown in FIG. 12, according to the distance between the mobile terminal device 152 in one communication system and the base station 14] of the mobile terminal device 140 in another communication system, one communication system can be selected. 150 channels.

When the cells of the base station 15' in one communication system 150 and 1% of the cells 143 in the base station of another communication system 140 are similar to those shown in FIG. 13, or when the sizes of the cells 143 and 153 are different from those in FIG. At the same time, the first embodiment is very effective in reducing the interference caused by the mobile terminal device 152 to the base station.

However, under the conditions shown in Figure 6 above, where the cell 113 in the other communication system is particularly smaller than the cell 123 in the first communication system, and some cells 113 are included in the cell 123, this is the case. Even if the base station near the base station 121 is separated from the mobile terminal device 122, another base station exists near the mobile terminal device 122. In this case, even if there is no interference to the base station M in the vicinity of the base station 121, it is possible to cause interference to the base station 1b in the vicinity of the mobile terminal device 122.

Therefore, in the radio communication system 120, according to the total received energy (interference energy Iall) of the signal other than those signals of the target mobile terminal device 122 in the channel allocation of the base station 12h, and according to the movement in the cell 123, of the base station 12h Total number of terminal devices 122

02120424.1 p.

N. Determine the channel allocation ratios α 1 and α 2 of the close channel group CHA and the far channel group CHB of the frequency band used by the radio communication system 110, where the cell 123. of the base station 12L controls the transmission energy of the mobile terminal device 122. In addition, in the radio communication system 120, based on the comparison result of the channel switching distance Dre and the distance between the base station 12h and the mobile terminal device 122, the channel to be allocated to one of the channel groups CHA and CHB is determined.

By realizing this channel allocation, interference to another radio communication system 110 can be easily reduced.

It should be noted that the above description refers to a structure in which the radio communication system 120 only uses FDMA to multiplex a set of channels, and it can also multiplex the channels through CDMA. At this time, the signal in each frequency channel is Extended encoding. In this case, each channel bandwidth adopted by the radio communication system 120 is approximately 5 MHz, and the frequency channel allocation process can be performed similarly to the above-mentioned case.

It should also be noted that the above description refers to a situation where the frequency band used by the radio communication system 120 is at a higher frequency than the frequency band used by the radio communication system 110, but the present invention can also be used in such a situation. That is, by appropriately changing the processing according to the frequency relationship, the frequency relationship in the frequency band is reversed.

In this way, in this second embodiment, according to the number of mobile terminal devices that realize communication with the second radio base station, and the total received energy (interference energy) of signals other than those from the mobile terminal device, the mobile terminal device is simultaneously received from the mobile terminal device. The signal reception energy received by the second radio base station is controlled to a constant value, the channel allocation ratio used for communication between the second radio base station and the mobile terminal device can be obtained, and the channel switching distance that will become the standard for switching channels is obtained based on the obtained allocation ratio , Obtain the distance between the second radio base station and the mobile terminal device, and when the obtained distance is greater than the channel switching distance, allocate a frequency channel far from the first frequency band to the communication between the second radio base station and the mobile terminal device.

As described above, the signal reception energy received by the second radio base station from the mobile terminal device is controlled to a constant value, so when the distance between the second radio base station and the mobile terminal device is greater than the channel switching distance, the transmission energy of the mobile terminal device Higher, and at the same time, the interference energy to the first radio base station is also larger.

Therefore, as described above, according to the communication between the second radio base station and the mobile terminal device

02120424.1 The first distance can easily reduce the interference to the first radio base station. In particular, when the coverage area (cell) of the first radio base station is smaller than the cell of the second radio base station, and many first radio base stations are in the cell of the second radio base station, the interference to the first base station will depend on the mobile terminal The transmission energy of the device can easily reduce interference by realizing channel allocation as described above.

In addition, by realizing this channel allocation, the characteristics required for the filter of the mobile terminal device can be relaxed. Therefore, it is helpful to reduce the size of the mobile terminal device and reduce the energy consumption.

In addition, it is possible to realize the channel allocation in consideration of the actual utilization state of the radio signal, so that the space utilization rate of the radio signal can be improved.

It should also be noted that in addition to those already mentioned, many modifications and changes to the above-mentioned embodiments can be made without departing from the novel and optimal features of the present invention. Therefore, all these modifications and changes should be included in the scope of the appended claims.

02120424.1