JPH0865730A - Radio channel allocation method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an autonomous distributed radio channel allocation method with a small control load and high frequency utilization efficiency. When a wireless channel allocation request is made, the wireless channel control device 14 confirms that there is an unused wireless channel, and the transmitter / receiver control device 13 receives unused transceivers 1, 2, ..., Ki. If there is a transmitter / receiver that can be used, the mobile unit characteristic measuring device controller 16 is instructed to extract the characteristic of the mobile station to which the wireless channel is to be assigned. The measurement result of this feature extraction is notified to the radio channel controller 14. This wireless channel control device 1
4 compares the measurement result with a threshold value for determining the priority table number stored in the memory 18, determines the priority table number, and refers to the assigned priority of the priority table number. Then, the wireless channel number with the highest allocation priority is selected from the unused wireless channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio channel allocation method in a mobile communication system for communicating between a radio base station and a mobile station.

[0002]

2. Description of the Related Art In the currently popular mobile phone and car phone systems, a radius of a radio zone serviced by one radio base station is set to about several kilometers and a large number of radio base stations are arranged in a service area. Cellular systems that provide services are well known.

Generally, in a cellular system, a so-called wireless channel is repeatedly used geographically for the purpose of effectively using a limited wireless channel, in which the same wireless channel is used by different wireless base stations geographically separated from each other. Is done. By making the distance between wireless base stations that use the same wireless channel as small as possible, high frequency utilization efficiency can be obtained, and the system capacity can be increased under the condition that the frequency bandwidth given to the system is constant. .

On the other hand, if the repetition distance of the wireless channel is reduced, interference from the same wireless channel and FDM
In the A method, the interference of sideband power of the wireless channel is allowed and the wireless channel is configured to interfere with adjacent wireless channels in the interleaved method. It cannot be made small, and it is necessary to repeatedly use the same radio channel in radio base stations that are spatially sufficiently separated so that these interferences do not exceed a certain allowable value. Methods for realizing repeated use of radio channels satisfying such conditions are roughly classified into a fixed channel allocation method and a dynamic channel allocation method. Further, the dynamic channel allocation includes a centralized control dynamic channel allocation method and an autonomous distributed dynamic channel. There is an allocation method.

The fixed channel allocation method is a method in which radio wave propagation conditions and traffic distribution are obtained by actual measurement or theoretical calculation, and radio channels are fixedly arranged in each radio base station. Generally, a large amount of labor is required for the design for determining the fixed arrangement, and further redesign is required when the equipment is additionally installed, so that there is a drawback that compatibility with system expansion is low. Further, since the wireless channels usable as the entire system are divided into some groups and assigned to each wireless base station, a division loss occurs, and high frequency utilization efficiency cannot be obtained.

On the other hand, the dynamic channel allocation system is
It is possible to allocate radio channels to some extent flexibly with respect to temporal fluctuations of traffic, spatial bias, etc.
Since the wireless channels that can be used in the entire system can be used by any wireless base station, a large grouping effect is obtained, and the frequency utilization efficiency is improved as compared with the fixed channel allocation method.

However, in order to minimize the call loss rate or the probability of occurrence of interference, a large amount of information and complicated control are generally required. In the centralized control type dynamic channel allocation method, each radio base station and control station are required. Signal traffic to and from it, and in the autonomous distributed dynamic channel allocation method, there are drawbacks that there is a lot of processing up to channel allocation and a large connection delay, so how much control load is low and high frequency utilization efficiency is achieved. It is very important to realize a wireless channel allocation scheme that can be obtained.

As a wireless channel allocation method for realizing autonomous distributed dynamic channel allocation with a relatively simple control method, the allocation priority of each wireless channel is calculated from the history of past allocation availability, and the allocation priority is high. Whether or not the wireless channel can be assigned is determined in order from the wireless channel. If it is determined that the wireless channel can be assigned, the wireless channel is assigned. Otherwise, the wireless channel with the next highest priority of assignment is moved to determine whether the wireless channel can be assigned. A wireless channel allocating method has been proposed (Japanese Patent Laid-Open No. 61-244137 and Japanese Patent Laid-Open No. 62-91033).

[0009] For example, the wireless communication system disclosed in Japanese Patent Laid-Open No. 61-244137 gives each channel a priority that is variably determined by the past history of channel use, and uses the channels in descending order of priority. In addition, the transmission channel control method disclosed in Japanese Patent Laid-Open No. 62-91033 stores the success rate of transmission for each channel and sequentially uses the channels with the highest success rate for transmission. The success rate is updated based on the transmission result.

[0010]

The above-mentioned conventional fixed channel allocation method has the drawbacks of low compatibility with system expansion and high frequency utilization efficiency.

Further, in the centralized control type dynamic channel allocation method among the dynamic channel allocation methods, the signal traffic between each radio base station and the control station increases,
In addition, the autonomous distributed dynamic channel allocation method has a drawback that a lot of processing is required until channel allocation, resulting in a large connection delay.

Further, as described above, a conventional autonomous distributed dynamic channel allocation method in which the allocation priority of each wireless channel is calculated from the past allocation availability history and the wireless channel is allocated based on the allocation priority. However, since only one priority is given to each wireless channel, the repeated use of the wireless channel is limited to the repeated use in units of wireless zones, and the frequency utilization efficiency is higher than that of the fixed channel allocation method. However, there is a drawback in that the wireless channels available for the entire system are limited to the improvement due to the large grouping effect obtained by allowing each wireless base station to use.

The present invention has been made in view of the above,
It is an object of the present invention to provide an autonomous distributed radio channel allocation method that has a small control load and can obtain high frequency utilization efficiency.

[0014]

In order to achieve the above object, a radio channel allocation method of the present invention is a mobile communication system for communicating between a mobile station and a radio base station, wherein the radio base station is the entire system. Of the wireless channels that can be used as a wireless channel, the wireless channel includes a function of transmitting and receiving one or a plurality of arbitrary wireless channels at the same time, and a function of measuring whether or not the selected wireless channel is available. Is it possible to select one or more radio channels from the radio channels that can be used for the entire system by referring to the assignment priority assigned to each of them, and to use them in order from the radio channel with the highest assignment priority? A wireless channel allocation method for determining whether or not to allocate a wireless channel, wherein the wireless base station manages N allocation priority tables. By the N number of allocation priority assigned to one radio channel, the state of the mobile station to be assigned a radio channel, the mobile station N
The gist is to divide into individual groups and allocate the wireless channels according to the allocation priority recorded in the allocation priority table corresponding to the group.

The radio channel allocation method of the present invention is
In the above, the gist is to adaptively determine the allocation priority of the wireless channel based on the past usage history of the wireless channel in the group.

Further, the wireless channel allocation method of the present invention is
In the above description, the gist is to adaptively determine the allocation priority of the wireless channel based on the past usage history of the wireless channel in the group and other groups.

The radio channel allocating method of the present invention is characterized in that, when allocating a radio channel, the distance from the radio base station of the mobile station is used as a state of the mobile station for grouping.

Further, the radio channel allocation method of the present invention is
In the above, when assigning a wireless channel, it is a gist to use the moving direction of the mobile station as a state of the mobile station for grouping.

Further, the radio channel allocation method of the present invention is
In the above, it is a gist to use the moving speed of the mobile station as a state of the mobile station for grouping when allocating the radio channel.

The radio channel allocating method of the present invention, in the above, arbitrarily combines the distance of the mobile station from the radio base station, the moving direction of the mobile station, and the moving speed of the mobile station when allocating the radio channel. The main point of this is to use as a state of the mobile station for grouping.

The radio channel allocating method of the present invention is characterized in that, in allocating a radio channel, at least one of the mobile station itself and the base station measures the state of the mobile station.

[0022]

According to the wireless channel allocation method of the present invention, the wireless base station manages N allocation priority tables,
N allocation priorities are assigned to one radio channel, and when allocating radio channels, the radio base station divides the mobile stations into N groups based on the extracted characteristics of the mobile stations, and divides the groups into N groups. Radio channels are allocated according to the allocation priority recorded in the corresponding allocation priority table.

In the wireless channel allocation method of the present invention, the allocation priority of the wireless channel is adaptively determined by the past usage history of the wireless channel in the group.

Further, in the wireless channel allocation method of the present invention, the allocation priority of the wireless channels is adaptively determined by the past usage history of the wireless channels in this group and other groups.

In the radio channel allocating method of the present invention, when allocating the radio channel, the distance of the mobile station from the radio base station is measured as the state of the mobile station.

Further, in the radio channel allocating method of the present invention, when allocating the radio channel, the moving direction of the mobile station is measured as the state of the mobile station.

Further, in the radio channel allocating method of the present invention, when allocating the radio channel, the moving speed of the mobile station is measured as the state of the mobile station.

In the radio channel allocation method of the present invention, when allocating a radio channel, a combination of the distance of the mobile station from the radio base station, the moving direction of the mobile station, and the moving speed of the mobile station is arbitrarily moved. It is measured as the state of the station.

In the radio channel assignment method of the present invention, when assigning a radio channel, the mobile station itself, the base station, or both appropriately measure the state of the mobile station, and depending on the state of the mobile station, for example, assignment priority is given. Assign wireless channels according to the degree.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a mobile communication system to which the wireless channel allocation method of the present invention is applied.
The mobile communication system shown in FIG.
1 and a plurality of mobile stations 12 that communicate with each other by connecting to the radio base station 11 using one or more radio channels.

In the entire mobile communication system configured as described above, M radio channels can be used, and the i-th radio base station 11 in the mobile communication system is the M radio channels.
Ki mobile transceivers capable of transmitting and receiving on any of the M radio channels are provided, and each mobile station 12 that communicates by connecting to the mobile communication system communicates with any of the M radio channels. It shall be equipped with a transceiver capable of transmitting and receiving on the channel.

FIG. 2 is a block diagram functionally showing the configuration of the radio base station 11 used in the mobile communication system shown in FIG. 1, particularly the configuration of the part related to radio channel allocation. In the radio base station 11 shown in the figure, Ki transceivers 1, 2, ...
, And the transceiver controller 13 is connected to the radio channel controller 14. In addition, the wireless base station,
A mobile device characteristic measuring device 15 for extracting the characteristics of the mobile station is provided, and the mobile device characteristic measuring device 15 controls the mobile device characteristic measuring device 15 for controlling the mobile device characteristic measuring device 15.
Through the radio channel controller 14.
Further, the radio channel controller 14 is connected to the call processing controller 17
And connected to the memory 18.

The radio channel controller 14 reads, updates, and writes data stored in the memory 18 in response to a request from the call processing controller 17, and the radio base station currently in use. Manage channels.
The transceiver control device 13 manages the transceivers 1, 2, ... Ki and determines whether or not the wireless channel designated by the wireless channel control device 14 can be assigned.

FIG. 3 conceptually shows an example of data stored in the memory 18. In this example, when assigning radio channels, the mobile stations are grouped according to the characteristics of the mobile station from the radio base station, the moving direction, and the moving speed. On the memory 18, a flag indicating whether M radio channels are in use or unused in the radio base station, N allocation priorities for one radio channel, and N mobile stations to which the radio channels are to be allocated. Thresholds such as a distance, a moving direction, a moving speed, etc. for sorting into individual groups are recorded.

FIG. 4 is a flow chart showing the processing procedure of the radio channel allocation method of the first embodiment in the mobile communication system shown in FIGS. The processing procedure of the wireless channel allocation method will be described with reference to the flowchart shown in FIG. In FIG. 4, when there is a request from the call processing controller 17 to assign a wireless channel for a new call or wireless channel switching, the wireless channel controller 14 checks whether or not there is a wireless channel that is not currently in use. Perform (step 110). If all the wireless channels are in use, the call processing controller 17 is notified to that effect, and the processing ends.

On the other hand, if there is a usable wireless channel in step 110, the wireless channel control device 1
4 inquires of the transceiver controller 13 whether or not there are transceivers 1, 2, ... Ki currently in use (step 120). If there is no transceiver that can be used, the transceiver controller 13 notifies the call processing controller 17 to that effect through the wireless channel controller 14 and ends the processing.

If there is a transceiver that can be used in step 120, the flow proceeds to step 130, in which the radio channel controller 14 sends the characteristics of the mobile station to which the radio channel is assigned to the mobile station characteristic measuring device controller 16. Upon commanding the extraction, the mobile unit characteristic measuring device controller 16 causes the mobile unit characteristic measuring unit 15 to measure the characteristic of the mobile station. Then step 1
Proceeding to 40, when the mobile device characteristic measuring instrument control device 16 receives the measurement result from the mobile device characteristic measuring instrument 15, it notifies the radio channel control device 14 of the measurement result. The radio channel controller 14 compares the notified measurement result with the threshold value for determining the priority table number stored in the memory 18, and determines the priority table number.

In step 150, the radio channel controller 1
4 refers to the allocation priority of the priority table number determined in step 140 on the memory 18, selects the wireless channel number having the highest allocation priority among the wireless channels currently not in use, and the transceiver Notify the control device 13. In step 160, the transceiver controller 13 determines whether or not the wireless channel can be used as described below, and returns the result to the wireless channel controller 14.

If the result of the availability decision in the transceiver controller 13 is yes, the radio channel controller 14 increases the allocation priority for the radio channel on the priority table (step 170), and the memory The above value is updated and the wireless channel number is set to the call processing control device 1
7 is notified, the used / unused flag of the wireless channel is set as being in use, and the wireless channel is allocated (step 175).

If the result of the wireless channel availability judgment in step 160 is unusable, the allocation priority for the wireless channel in the priority table is decreased (step 180) and the value in the memory is updated. Then
Select the next highest priority wireless channel (step 1
90, 200) and returns to step 160 to repeat the same processing.

If the result of the usability judgment for all the radio channels that are not currently in use is unusable, the radio channel controller 14 notifies the processing controller to that effect,
The process ends (step 190).

Various methods are conceivable as a method of determining whether or not the wireless channel can be allocated in the processing of steps 150 and 160 in the above-described wireless channel allocation method. For example, one of the transceivers that is not used can be used. A method of setting the wireless channel, receiving the signal, and determining that the reception level, that is, the interference wave level is less than or equal to a predetermined threshold, determines that allocation is possible, and temporarily setting the wireless channel to the mobile station of the other party. And send a notification on that radio channel,
This is received by the wireless base station, the power ratio between the desired wave and the interference wave on the wireless channel is measured, and if this is above a certain threshold, allocation is possible. A method of using the result of measuring the interference wave level or the power ratio between the desired wave and the interference wave at the mobile station and comparing it with a predetermined threshold value, etc. There is.

The interference wave level threshold value and the threshold value of the power ratio of the desired wave and the interference wave used at this time may be the same threshold value for all groups, or different threshold values may be used for each group. Good. For example, regarding the power ratio between the desired wave and the interference wave, it is considered that the fluctuation of the communication state is small in a mobile station with a slow moving speed, so a small margin is set for the required value, and conversely, in the case of a mobile station with a high moving speed, It is conceivable to increase the margin for the required value. Similarly, for the interference wave level, increase the interference wave level threshold for mobile stations near the radio base station and decrease the interference wave level threshold for mobile stations at the cell edge so as to satisfy the required communication quality. It is possible to set it.

FIGS. 2 and 4 show examples in which the radio base station measures the state of the mobile station when allocating the radio channel. The measurement of the status of the mobile station can be configured to be performed by the mobile station. In this case, for example, a method in which the mobile station measures the state of its own station by a command from the radio base station at the time of an incoming / outgoing call and reports it to the radio base station, or the mobile station autonomously sets its own station at the time of an incoming / outgoing call or idle. A possible method is to measure the status and report it to the radio base station. In any case, the present invention can be applied and the same effect can be obtained.

In the above-mentioned control flow, the method of setting the allocation priority based on the result of the allocation approval / disapproval determination in the group has been described. However, a method of defining the allocation priority from the result of the allocation approval / disapproval judgment of the group and other groups may be considered. . For example, if the result of the assignment availability judgment is yes, the assignment priority is increased by increasing the assignment priority of the group for the wireless channel and simultaneously lowering the assignment priority of the other group of the wireless channel. The convergence time can be shortened. By performing the above processing, the wireless channels are automatically used in the wireless base station according to the characteristics of the mobile station, and the wireless channels are also automatically used between the wireless base stations. A high quality wireless channel allocation method can be realized by simple control.

An example of the allocation priority for each radio base station and each group will be described based on the result of computer simulation. As shown in FIG. 5, there are two adjacent radio base stations, and the number of radio channels is 5 in total. The number of priority tables, that is, the number of groups is 3,
As a feature of mobile stations, only the distance from the radio base station was measured and grouped. The distance of the mobile station from the radio base station was estimated by measuring the reception level of the radio wave transmitted by the mobile station at the radio base station. In addition, it is assumed that the call origination follows the Poisson distribution and is uniformly distributed in the wireless zone. The call volume applied to the two wireless zones was assumed to be equal. The method of judging whether or not allocation is possible is that allocation is possible if the ratio of the desired wave and the interference wave of the uplink and downlink is above a threshold value. As the interference wave, only co-channel interference was considered.

FIG. 6 shows allocation priorities in both radio base stations after a lapse of a sufficient time from the start of simulation. FIG. 6A shows the allocation priority of the priority table # 1,
Assignment priority used for mobile stations close to the radio base station, FIG. 6 (b) is assignment priority used for mobile stations with a medium distance from the radio base station, and FIG. 6 (c) is radio base station. It is an allocation priority used for a mobile station far away from. In the graph of each allocation priority, the larger the value on the vertical axis, the higher the priority.

In FIG. 6A, channel 0 has the highest allocation priority in both base stations.
It can be seen that the same radio channel is used with high priority in the adjacent radio zones for mobile stations that are close to the radio base station. 6 (b) and 6
In (c), the radio base station 1 and the radio base station 2 have different radio channels with high allocation priorities. For example, FIG.
In (c), wireless channel 2 has the highest allocation priority in wireless base station 1 and wireless channel 4 has the highest allocation priority in wireless base station 2. It can be seen that different radio channels are used, avoiding the occurrence of interference from other radio zones.

Furthermore, it can be seen that even within the same radio base station, the radio channels are automatically used separately from other groups. For example, the wireless base station 1 of FIG. 6A has a high allocation priority for channel 0, and the wireless base station 1 of FIGS. 6B and 6C has a low allocation priority of channel 0. 6B, the allocation priority of channel 3 is high in the wireless base station of FIG. 6B, and the allocation priority of channel 3 of the wireless base station 1 of FIGS. 6A and 6C is high. The degree is low.

Generally, in the case of a mobile station located far from the radio base station and located at the end of the radio zone, the reception level of the desired wave is low in both the up and down links, so the radio channel assigned to such a mobile station is In order to prevent the deterioration of the call quality, it is necessary to repeatedly use the signal at a relatively large distance so that the interference wave level from the surrounding wireless base station or mobile station can be kept low. On the other hand, in the case of a mobile station that is close to the radio base station, the desired signal reception level is secured to some extent, so even if a radio channel with a small repeat distance is used compared to a mobile station located at the edge of the radio zone. Communication quality does not deteriorate.

Therefore, it is possible to improve frequency utilization efficiency by selectively using a radio channel having a large repeating distance and a radio channel having a small repeating distance according to the distance between the radio base station and the mobile station. In the radio channel assignment method of the present invention, the use of the radio channel between the radio base stations and between the radio base stations is automatically selected according to the characteristics of the mobile stations by the autonomous distributed control of the base stations, so that the frequency utilization efficiency and the communication quality are improved. A high radio channel allocation method can be realized with simple control.

A computer simulation performed for quantitatively confirming the effect of the present invention and the result thereof will be described. In this simulation, the wireless zone is a hexagonal omnicell, and the service area is composed of 61 wireless zones. The call generation follows the Poisson distribution and occurs spatially uniformly within the wireless zone. Average call hold time is 1
It is assumed to follow an exponential distribution of 20 seconds. Also, it is assumed that the habits of calls within each wireless zone are the same. It is assumed that the mobile station that is going to make or receive a call selects the wireless zone by measuring the received power of the perch channel (control channel) transmitted from the wireless base station at a constant transmission power in advance. . In addition, the number of wireless channels that can be used in the entire system is 35, and only co-channel interference is considered as interference. The number of priority tables, that is, the number of groups was set to 7, and as a feature of the mobile station, only the distance from the radio base station was measured and the grouping was performed. The distance of the mobile station from the radio base station was estimated by measuring the reception level of the radio wave transmitted by the mobile station at the radio base station. The method of judging whether or not allocation is possible is that allocation is possible if the ratio of the desired wave and the interference wave of the uplink and downlink is above a threshold value.

7 and 8 show the results of the above computer simulation. The accommodated call volume is defined as the applied call volume per one wireless zone at a call loss rate of 3%. FIG. 7 shows the call loss rate. The horizontal axis is the applied call volume, which is standardized by the accommodating call volume of the conventional wireless channel allocation method using a single allocation priority. Further, FIG. 8 shows the number of times of determination as to whether or not allocation is required for allocating one call, which is standardized by the value of the accommodating call volume of the conventional system. The horizontal axis is the call loss rate.

From the results of this computer simulation, according to the wireless channel allocation method of the present invention, the capacity of calls accommodated is improved by about 25% as compared with the conventional wireless channel allocation method using a single allocation priority. In addition, it was confirmed that the number of times of determination as to whether or not allocation was required for allocating a wireless channel to one call was reduced by about 10% in the accommodated call volume, and it was significantly improved.

From the above computer simulation results,
According to the present invention, compared with the conventional radio channel allocation method using a single allocation priority, it is possible to significantly increase the accommodated call volume and suppress the control load to a sufficiently small level. A wireless channel allocation method that is small and that can obtain high frequency utilization efficiency can be realized.

In the above computer simulation, the distance from the radio base station of the mobile station is extracted as the mobile station characteristic, but the same simple operation is performed when the moving speed and the moving direction of the mobile station are extracted as the mobile station characteristic. , A similar effect can be obtained. In the method of assigning a wireless channel without considering the moving direction and moving speed of the mobile station, when the mobile station moves at high speed, the frequency of the mobile station moving in the wireless zone increases and the wireless zone The rate of forced disconnection that occurs because channels are not allocated increases, and the control load for switching radio channels increases on the radio base station side and the mobile station side.

Further, since there are mobile stations moving at high speed, the interference condition fluctuates greatly in time, and the probability of occurrence of interference increases for both mobile stations moving at high speed and mobile stations moving at low speed. . Therefore, when mobile stations with different moving speeds are mixed in the service area, the moving speeds of the mobile stations,
It is necessary to use different wireless channels depending on the moving direction.

According to the radio channel allocation method of the present invention, mobile stations are divided into groups according to the moving direction and the moving speed of the mobile stations, and the radio channels are allocated using the allocation priority corresponding to the group. As in the case of extracting the distance to the mobile station, the channels are automatically used properly, and it is possible to minimize the decrease in control load and frequency utilization efficiency.

As the radio channel, it is considered that radio frequency is used in the FDMA system, radio frequency and time slot in the TDMA system, and spreading code or frequency hopping pattern is repeatedly used in the CDMA system. In the case where the radio channel is configured by any method such as time slot and spreading code, the present invention can determine whether or not the radio channel can be allocated by measuring the interference level or the power ratio of the desired wave to the interference wave. Method is applicable and the same effect can be obtained.

Next, the second embodiment will be described. In the above-described first embodiment, the method of determining the allocation priority based on the allocation result within the own group has been shown. The second embodiment shows a specific method for adaptively determining the assignment priority of a wireless channel based on the past usage history of the wireless channel in the group and other groups. This second
The method shown in the second embodiment differs from the method of the first embodiment only in the method of updating the allocation priority of the radio channels of each group.

First, referring to FIG. 1, in the second embodiment, as in the first embodiment, M radio channels can be used in the entire system. The th wireless base station 11 is provided with Ki transceivers capable of transmitting and receiving on any wireless channel of the M wireless channels, and each mobile station 12 connected to this mobile communication system for communication is It is assumed that a transmitter / receiver capable of transmitting / receiving on an arbitrary wireless channel among the individual wireless channels is provided.

FIGS. 9 and 10 are flowcharts showing the processing procedure of the radio channel allocation method of the second embodiment in the mobile communication systems shown in FIGS. Hereinafter, referring to the flowcharts shown in FIGS. 9 and 10, the second
A processing procedure of the wireless channel allocation method according to the embodiment will be described. In FIG. 9, first, when there is a request from the call processing controller 17 for a new call or a wireless channel allocation for switching a wireless channel, the wireless channel controller 14
Checks whether there is a wireless channel that is not currently in use (step 310). If all wireless channels are in use, the call processing controller 17
Is notified and the process ends.

On the other hand, if there is a usable wireless channel in step 310, the wireless channel control device 1
4 inquires of the transceiver control device 13 whether or not there are transceivers 1, 2, ..., Ki currently in use (step 320). If there is no transceiver that can be used, the transceiver controller 13 notifies the call processing controller 17 to that effect through the wireless channel controller 14 and ends the processing.

If there is a transceiver that can be used in step 320, the flow proceeds to step 330, in which the radio channel controller 14 determines the characteristics of the mobile station to which the radio channel is to be allocated to the mobile station characteristic measuring device controller 16. Upon commanding the extraction, the mobile unit characteristic measuring device controller 16 causes the mobile unit characteristic measuring unit 15 to measure the characteristic of the mobile station. Next step 3
Proceeding to 40, when the mobile device characteristic measuring instrument control device 16 receives the measurement result from the mobile device characteristic measuring instrument 15, it notifies the radio channel control device 14 of the measurement result. The radio channel controller 14 compares the notified measurement result with the threshold value for determining the priority table number stored in the memory 18, and determines the priority table number.

In step 350, the radio channel controller 1
4 refers to the allocation priority in the memory 18 based on the priority table number determined in step 340, selects the wireless channel number with the highest allocation priority among the wireless channels not currently in use, and transmits / receives it. The machine control device 13 is notified. In step 360, the transceiver controller 13 determines whether or not the wireless channel can be used by a method similar to the method described in the first embodiment, and returns the result to the wireless channel controller 14.

The radio channel controller 14 updates the allocation priority stored in the memory 18 shown in FIG. 10 when the result of the availability judgment in the transceiver controller 13 is usable (step 370). ). In addition, FIG.
FIG. 3 is a conceptual diagram of an allocation priority table used for explaining the method of updating the allocation priority in this case, in which the horizontal axis indicates the group number and the vertical axis indicates the channel number.
In addition, in the flowchart showing the processing procedure of FIG.
The determined group number will be described as G, and the wireless channel number determined to be usable will be described as CH.

Step 371: In the group whose group number is less than G, the allocation priority is raised for all channels whose channel numbers are less than CH. The target wireless channel is a wireless channel in the range I in FIG. Step 373: In the group having a group number larger than G, the allocation priority is lowered for all channels having channel numbers equal to or lower than CH. The target wireless channel is a wireless channel in the range II in FIG. Step 375: In the group whose group number is less than G, the allocation priority is lowered for all channels whose channel numbers are CH and above. The target wireless channel is a wireless channel in the range III in FIG. Step 377: In the group having the group number larger than G, the allocation priority is raised for all the channels having the channel number larger than CH. The target wireless channel is a wireless channel in the range IV in FIG. Step 379: Increase the allocation priority of the channel CH of the group G.

Based on the above-mentioned five steps, the value in the memory 18 is updated by the obtained allocation priority, the wireless channel number is notified to the call processing controller 17, and the used / unused flag of the wireless channel. Is set to be in use, and the wireless channel allocation process is performed. At this time,
The above-mentioned five steps do not have to be executed in this order, and even if they are executed before and after each other, the resulting allocation priorities are equal.

Returning again to the flowchart of FIG. 9, if the result of the wireless channel availability determination is unusable, the allocation priority for the wireless channel in the priority table is decreased (step 390) and the memory is stored. 18
The above value is updated, the wireless channel with the next highest allocation priority is selected, and the same processing is repeated (steps 400 and 41).
0). When the availability determination result for all wireless channels that are not currently in use is unavailable, the wireless channel control device 14 notifies the call processing control device 17 to that effect,
The process ends (step 400).

As described in the first embodiment, the threshold value of the interference wave level and the threshold value of the power ratio of the desired wave and the interference wave used at this time may be the same threshold value in all groups, Separate thresholds may be used for each group.

Further, in the second embodiment, an example in which the radio base station measures the state of the mobile station at the time of radio channel allocation is shown, but as described in the first embodiment,
The measurement of the status of the mobile station can be configured to be performed by the mobile station.

By executing the above processing, the radio channel is automatically used properly in the radio base station according to the characteristics of the mobile station, and the radio channel is automatically used among the radio base stations. Further, since the allocation priority of the wireless channel is adaptively determined based on the past usage history of the wireless channel in the group and other groups, the use of the channel in the wireless base station becomes clearer, and the first A radio channel allocation method with higher frequency utilization efficiency than that of the embodiment can be realized by simple control.

A computer simulation carried out to quantitatively confirm the effect of the method of the second embodiment of the present invention and the result thereof will be described. In this simulation, the wireless zone is a hexagonal omnicell, the service area is composed of 61 wireless zones, and calls are generated spatially and uniformly within the wireless zone according to Poisson distribution. The holding time of s shall follow an exponential distribution with an average of 120 seconds. Also, it is assumed that the habits of calls within each wireless zone are the same. It is assumed that the mobile station that is going to make or receive a call selects the wireless zone by measuring the received power of the perch channel (control channel) transmitted from the wireless base station at a constant transmission power in advance. .
The number of wireless channels that can be used in the entire system is 7
As the 0 channel, only co-channel interference was considered as interference. The number of priority tables, that is, the number of groups was 30, and the distance of the mobile station from the radio base station was estimated by measuring the reception level of the radio wave transmitted by the mobile station at the radio base station. The method of judging whether or not allocation is possible is that allocation is possible if the ratio of the desired wave and the interference wave of the uplink and downlink is above a threshold value.

FIG. 7 shows the result of the computer simulation. FIG. 7 shows the loss probability characteristic. The horizontal axis represents the applied call volume per one wireless zone, which is standardized by the accommodated call volume of the conventional wireless channel allocation method using a single allocation priority. The accommodated call volume is defined as the applied call volume per one wireless zone at a call loss rate of 3%.

From the result of this computer simulation, according to the wireless channel allocation method of the second embodiment of the present invention, the accommodated call volume is compared with the conventional wireless channel allocation method using a single allocation priority. Was improved by about 60%, and it was confirmed that it was improved by about 28% as compared with the wireless channel allocation method of the first embodiment according to the present invention.

From the result of the above computer simulation, according to the method of the second embodiment, the accommodated call volume is significantly increased as compared with the conventional radio channel allocation method using a single allocation priority. Therefore, it is possible to realize a radio channel allocation method capable of obtaining high frequency utilization efficiency with simple control.

Further, in the above computer simulation,
Although the distance of the mobile station from the radio base station is extracted as the characteristic of the mobile station, the same is true when the moving speed and the moving direction of the mobile station are extracted as the characteristics of the mobile station as in the method of the first embodiment. The same effect can be obtained with a simple operation.

As the radio channel, it is possible to repeatedly use the radio frequency in the FDMA system, the radio frequency and the time slot in the TDMA system, and the spread code or the frequency hopping pattern in the CDMA system. Similar to the method, in the method of the second embodiment, the interference level or the desired wave-to-interference wave is generated even when the wireless channel is configured by any method such as radio frequency, time slot, spreading code, frequency hopping pattern. It is applicable by determining the radio channel allocation availability by measuring the power ratio, etc., and the same effect can be obtained.

[0079]

As described above, according to the present invention,
The wireless base station manages the N allocation priority tables to give N allocation priorities to one wireless channel, and the wireless base station measures the state of the mobile station when the wireless channel is allocated. By extracting the mobile device characteristics,
Based on the result, the mobile stations are divided into N groups, and the wireless channels are allocated according to the allocation priority recorded in the allocation priority table corresponding to the group,
Frequency allocation efficiency is calculated by calculating the allocation priority of each wireless channel from the past allocation availability history and comparing it with the conventional autonomous distributed dynamic channel allocation method that allocates wireless channels based on the allocation priority. It is possible to realize a wireless channel allocation method that can significantly increase the control load and suppress the control load to a sufficiently small level, reduce the control load, and obtain high frequency utilization efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a mobile communication system to which a radio channel allocation method of the present invention is applied.

2 is a block diagram functionally showing a configuration of a radio base station used in the mobile communication system shown in FIG. 1, particularly a configuration of a portion related to radio channel allocation.

FIG. 3 is a conceptual diagram of data stored in a memory used in the wireless base station shown in FIG.

FIG. 4 is a flowchart showing a processing procedure of a radio channel allocation method in the mobile communication system shown in FIGS. 1 to 3.

FIG. 5 is a diagram illustrating a computer simulation model performed to show the learning effect of the allocation priority.

FIG. 6 is a diagram illustrating an example of a learning result of allocation priority.

FIG. 7 is a call loss rate characteristic diagram showing a result of computer simulation performed to confirm the effects of the first and second embodiments.

FIG. 8 is a diagram showing a result of a computer simulation performed to confirm the effect of the present invention.

FIG. 9 is a flowchart showing a processing procedure of a wireless channel allocation method according to a second embodiment of the present invention.

FIG. 10 is a flowchart showing a processing procedure of a wireless channel allocation method according to a second embodiment of the present invention.

FIG. 11 is a conceptual diagram of an allocation priority table used for explaining an allocation priority updating method.

[Explanation of symbols]

 1, 2, ..., Ki Transceiver 11 Radio base station 12 Mobile station 13 Transceiver control device 14 Radio channel control device 15 Mobile device characteristic measuring instrument 16 Mobile device characteristic measuring instrument control device 17 Call processing control device 18 Memory

Claims (8)

[Claims] 1. In a mobile communication system for communicating between a mobile station and a radio base station, the radio base station can transmit / receive one or a plurality of arbitrary radio channels among radio channels usable as a whole system. A radio having a function and a function of measuring whether or not a selected radio channel is usable, and a radio that can be used as a whole system by referring to an allocation priority given to each radio channel in the radio base station. A wireless channel allocation method for selecting one or a plurality of wireless channels from among channels, deciding whether or not the wireless channels can be used in order from a wireless channel having a high allocation priority, and allocating wireless channels, The radio base station assigns N allocation priorities to one radio channel by managing N allocation priority tables, According to the state of the mobile station to which the line channel is to be allocated, the mobile station is divided into N groups, and the radio channel is allocated according to the allocation priority recorded in the allocation priority table corresponding to the group. Channel allocation method. 2. The wireless channel allocation method according to claim 1, wherein the allocation priority of the wireless channels is adaptively determined based on the past usage history of the wireless channels in the group. 3. The wireless channel allocation priority is adaptively determined by the past usage history of wireless channels in the group and other groups.
The described wireless channel allocation method. 4. The radio according to claim 1, wherein when allocating the radio channel, the distance from the radio base station of the mobile station is used for grouping as the state of the mobile station. Channel allocation method. 5. The radio channel allocation method according to claim 1, wherein when allocating a radio channel, the moving direction of the mobile station is used for grouping as the state of the mobile station. . 6. When allocating a radio channel, the moving speed of a mobile station is used as a state of the mobile station for grouping.
The described wireless channel allocation method. 7. When allocating a radio channel, a combination of the distance of the mobile station from the radio base station, the moving direction of the mobile station, and the moving speed of the mobile station is arbitrarily grouped as the state of the mobile station. The wireless channel allocation method according to claim 1, 2, or 3, wherein the wireless channel allocation method is provided. 8. The method according to claim 1, wherein the state of the mobile station is measured by at least one of the mobile station itself and the base station when allocating a radio channel.
Alternatively, the wireless channel allocation method according to claim 3.