JPH11205220A - Mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the utilizing efficiency of the system by reducing number of transmitters and receivers of a base station per cell. SOLUTION: The mobile communication system selects a base station making communication with a mobile station depending on a reception characteristic in each base station receiving a desired wave sent by the mobile station among a plurality of the base stations 31, 32, 33 each having receivers whose number corresponds to number of channels assigned to a cell. Number of the transmitters mounted on each base station is less than number of the channels above. Thus, the number of the transmitters is reduced more than that of a conventional system and the utilizing efficiency is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and is suitably used, for example, when performing site diversity (ie, macro diversity) with a cellular mobile phone.

[0002]

2. Description of the Related Art There is the following document 1 as a document relating to this kind of conventional technology.

Reference 1 "Outage Probability in Mobile Telephony with Directive Antennas and Macrodiversity" Author YU-SHUAN YEH, JOANNE C. WILSON, and STUART C. SCHWARTZ Source IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY (VOL.VT-33, NO.3 In this document 1, three base stations receive a signal (desired signal) from a mobile station existing in a cell and measure the maximum desired wave power. Communicating with the station. FIG. 2 shows the base station selector 9 when the number of channels allocated to this cell is N.

In FIG. 2, N base stations 1 are provided with N receivers 10 to 11 in the same number as the number N of reception channels in case N mobile stations at the maximum transmit a desired wave at the same time. . Each of the receivers 10 to 11 has a reception channel N
Among them, fixed channel receivers that can correspond to only one reception channel, and the corresponding reception channel numbers (1) to (N) are added to the respective receivers.

[0005] Each of the receivers 10 to 11 is connected to one of the desired wave power measuring devices 12 to 13. The desired wave power measuring devices 12 to 13 are devices for measuring the power of the desired wave transmitted from the mobile station at the base station 1, and the reception channel numbers (1) to (1) corresponding to each desired wave power measuring device.
(N) is added. All the measurement results of the desired wave power are sent to the base station selecting device 16.

In the base station 1, fixed channel transmitters 14 to 15 corresponding to each transmission channel among the transmission channels N are provided, and each transmitter has a corresponding transmission channel number ( 1) to (N) are added.

[0007] Base station 2 having the same configuration as base station 1
Are the receivers 17 corresponding to the reception channels (1) to (N).
, And desired wave power measuring devices 19 to 20, and transmitters 21 to 22 corresponding to the transmission channels (1) to (N).

[0008] Similarly, the base station 3 receives signals from the receiving channels (1) to (1)
There are provided receivers 23 to 24 corresponding to (N), desired wave power measuring devices 25 to 26, and transmitters 27 to 28 corresponding to transmission channels (1) to (N).

A desired wave transmitted from a certain mobile station in a cell on channel (1) is received by receivers 10, 17, and 23 on receiving channel (1) of base stations 1 to 3. Then, the desired wave power measuring devices 12, 19, and 25 connected to each receiver are
The power of the desired wave at each base station is measured, and the measurement result is supplied to the base station selecting device 16.

The base station selector 16 determines the largest one of the three desired wave power measurement results supplied from each base station, and selects the base station that has provided the maximum desired wave power. Assuming that this is the base station 3, TDD (Time Division Duplex) that multiplexes uplink and downlink channels in a time-division manner.
In the case of the plex) system, the base station selection device 16 operates the transmitter 27 of the transmission channel (1) in the base station 3 to communicate with the mobile station using the receiver 23 and the transmitter 27 of the base station 3. Communication with other terminals is performed.

[0011] Even during the communication between the mobile station and the other terminal, the signal output from the receiver 23 is continuously supplied to the desired wave power measuring device 25. Supplies the desired wave of the received channel (1) to the desired wave power measuring device 25 while mediating communication between the mobile station and another terminal, thereby contributing to base station selection.

When the base station that measures the maximum desired wave power is switched due to the mobile station, which is communicating with another terminal on channel (1), moving in the cell, the selected base station becomes the base station. The base station switches from 3 to the base station that measured the maximum desired wave power, for example, base station 2. At this time, base station 2
Receiver 17 and transmitter 21 of the mobile station mediate communication between the mobile station and another terminal.

[0013]

However, in the system as shown in FIG. 2, each base station has the same number of receivers and transmitters as the number of channels allocated to the cell.
There are receivers and transmitters that are three times as many as the number of channels in a cell, including three base stations, but at most one-third of these are used for communication between mobile stations and other terminals. Absent. Since the other two-thirds or more are hardly used except for the base station selection, the utilization efficiency of the receiver is low. For transmitters that are not used for selection,
Even lower.

That is, in the system shown in FIG. 2, the number of base station transmitters and the number of receivers per cell are large and the efficiency is low.

[0015]

In order to solve this problem, according to the present invention, a mobile station transmits a signal from a plurality of base stations having a number of receivers corresponding to the number of channels allocated to a cell. In a mobile communication system that selects a base station that communicates with the mobile station according to the reception characteristics of the desired wave at each base station, the number of transmitters mounted on each base station is smaller than the number of channels. Characterized by

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) First Embodiment In this embodiment, attention is paid to the fact that a transmitter in a base station is used only for communication after base station selection, and is used for communication for each base station. By selecting a base station based on data on the number of transmitters that have not been transmitted (the number of empty transmitters), it is possible to reduce the number of transmitters as compared with the related art and to increase the utilization efficiency of the transmitter compared to the related art. I do.

Hereinafter, the first embodiment of the mobile communication system according to the present invention will be described by taking as an example a case where uplink and downlink channels between a mobile station and a base station are multiplexed by the TDD system.

(A-1) Configuration of the First Embodiment FIG. 1 is a schematic diagram of the base station selection unit 30 of the mobile communication system according to the first embodiment. The base stations 31 to 33 in FIG.
Are three base stations arranged, for example, at substantially equal intervals on the boundary line of one cell, and these three base stations 31 to 33 cooperate to cover the cell. Base stations 31-33
, Also cover, for example, adjacent cells to which different channels are assigned, but the components for the adjacent cells in each of the base stations 31 to 33 are not shown. Therefore, in general, when a different channel is allocated to an adjacent cell, each of the base stations 31 to 33 is provided with the number of adjacent cells covering almost the same configuration as that illustrated.

In FIG. 1, a base station 31 includes fixed channel receivers 34 to 35 in the same number as the number N of channels allocated to the cell. The numbers (1) to (N) of the receiving channels are added to the respective receivers 34 to 35.

Each of the receivers 34 to 35 is connected to one of the desired wave power measuring devices 36 to 37. The desired wave power measuring devices 36 to 37 are devices for measuring the power of the desired wave transmitted from the mobile station in the cell in the base station 31, and the reception channel number (1) corresponding to each desired wave power measuring device. To (N).

The desired-wave power measuring devices 36 to 37 may be configured by applying, for example, an "interference detection method using sample values" described in the following document 2.

Reference 2 “Co-channel interference measurement in digital mobile communications” Author Jin Itoichi Yoshihiko Akaiwa Source Transactions of the Institute of Electronics, Information and Communication Engineers (Jan. 1997) B-2 Vol.J80-B-2 No.1 pp.10-17 In Reference 2, interference and noise power are extracted by first taking the difference between the sample values of the inversely modulated desired signal based on the decision result after synchronous detection, and then the sample of the desired signal after synchronous detection An estimated value of the average power of the desired wave is obtained by subtracting a value obtained by dividing the average power of the vector due to noise and interference by 2 from the average power of the value.

The measurement results of the desired wave power by the desired wave power measuring devices 36 to 37 are sent to the base station selecting device 38.

Up to this point, except for the specific configuration of the desired wave power measuring apparatus, the configuration is the same as that of base station selecting section 9 in FIG. 2, but in the present embodiment, the number of transmitters M in base station 31 is Less than the number N. The relationship between M and N is determined in consideration of the number of base stations covering the cell, required communication quality, device utilization efficiency, and the like.

For example, in the case of N = 10, the use efficiency of the transmitter can be improved by setting M = 4 for all three base stations, but M is not necessarily limited to the three base stations 31 to 31.
33 need not be identical. For each base station, base station 3
1, M = 2 for the base station 32, M = 3 for the base station 33, and M = 5 for the base station 33, so that N = 10 may be divided without excess or deficiency. In such a case, the use efficiency of the channel and the device is the highest. The value of M for each base station may be determined in consideration of the degree of gathering of people near the location where the base station is installed. In order to improve the communication quality, N should be close to M.

As described above, M is smaller than the number N of channels, but the number N of channels is originally determined in consideration of nearby communication traffic and the like when a base station is installed. This communication traffic is also taken into consideration when determining M, and M cannot be reduced without limit regardless of N. In this sense, M can be said to correspond to N.

On the other hand, the transmitters 39 to 40 in the base station 31 are channel switchable transmitters, and the transmission channel (X) is changed according to the control from the base station selecting device 38.

In this embodiment, the channel switching range of one of the transmitters 39 to 40 is (1) to (4).
(N). However, the channel switching range may be set so that M transmitters share (1) to (N) without duplication, or may be set so as to partially share duplication. The entire range, sharing without duplication, and sharing partially with each other may be mixed. Transmitters 39-4
0 may include a fixed-channel transmitter that cannot switch channels.

The base station 31 includes a signal line 31A for transmitting the number of transmitters in the base station 31 not used for communication, that is, the number of empty transmitters, to the base station selecting device 38.

Base station 3 having the same configuration as base station 31
2 is a receiver 4 corresponding to the reception channels (1) to (N).
3 to 44, and desired wave power measuring devices 45 to 46, M
And transmitters 47 to 48 capable of switching channels of the devices. The base station 32 also has a signal line 32A for transmitting the number of available transmitters in the base station 32 to the base station selecting device 38.

Similarly, the base station 33 sets the reception channel (1)
To (N), desired-wave power measuring devices 51 to 52, and M channel-switchable transmitters 53 to 54. The base station 33 also has a signal line 33A for transmitting the number of available transmitters in the base station 33 to the base station selecting device 38.

However, the number of transmitters M is three base stations 31-31.
Not all 33 need be the same.

The base station selecting device 38 connected to each of the base stations 31 to 33 has the highest desired wave power measuring device among the base stations in which the number of available transmitters obtained from the signal lines 31A to 33A is not zero. This is an apparatus that selects one of the base stations whose wave power has been measured, and causes the base station to perform communication with the mobile station.

The criterion for the number of vacant transmitters does not necessarily have to be 0, and it is not necessary that all the three base stations 31 to 33 have the same value.

The operation of the first embodiment having the above configuration will be described below.

(A-2) Operation of First Embodiment A desired wave that a certain mobile station in a cell is transmitting on channel (1) is transmitted to a receiver of fixed reception channel (1) of base stations 31 to 33. 34, 43 and 49 are always received. Then, the desired wave power measuring devices 36, 45, connected to each receiver,
51 measures the power of the desired wave at each base station,
The measurement result is supplied to the base station selection device 38.

Each of the base stations 31-33 is connected to a signal line 31A-31.
Via 33A, data on the number of vacant transmitters for each base station is transmitted to the base station selecting device 38.

Based on the number of empty transmitters, the base station selector 38 determines that the number of empty transmitters in the base stations 31 to 33 is zero.
If there is a base station that cannot transmit to the mobile station, the base station is excluded from candidates for selection. Here, it is assumed that the number of available transmitters is not zero in all of the base stations 31 to 33.

Next, the base station selecting device 38 determines the largest one of the three desired wave power measurement results supplied from each base station, and selects the base station that has provided the maximum desired wave power.

Assuming that this is the base station 33, the base station selecting device 38 selects an arbitrary empty transmitter in the base station 33, for example, the transmitter 53, and sets the transmission channel of the transmitter 53 to the channel (1). Let it.

Thus, the mobile station can communicate with other terminals with good quality via the receiver 49 and the transmitter 53 of the base station 33.

During this communication, the channel (1) is also received by the receivers 34 and 43 of the base stations 31 and 32, and the measurement results of the desired wave power measuring devices 36, 45 and 51 are supplied to the base station selecting device 38. Have been.

Therefore, 3
Among the measurement results, for example, the desired wave power measuring device 45
Is maximum, the base station selecting device 38 selects a vacant transmitter in the base station 32, for example, the transmitter 48, if the number of vacant transmitters of the base station 32 is not 0 at that time, and selects its transmission channel. Is set to channel (1).

Thus, the base station that mediates communication with the other terminal of the mobile station is switched from the base station 33 to the base station 32, and the quality of the communication is maintained. Thereafter, similar operations are repeated as necessary.

(A-3) Effects of the First Embodiment As described above, according to the first embodiment, the number of transmitters mounted on a base station is reduced as compared with the related art, and the Use efficiency can be improved.

Further, since priority is given to information on the number of vacant transmitters for each base station covering a common cell and base station selection is performed in consideration of the desired signal power, the communication quality is reduced, if at all. The utilization efficiency of the transmitter per cell is high.

(B) Second Embodiment Hereinafter, the uplink and downlink channels between the mobile station and the base station are defined as TD.
The second embodiment of the mobile communication system according to the present invention will be described by taking the case of multiplexing in the D system as an example.

(B-1) Configuration of the Second Embodiment FIG. 3 shows a schematic diagram of the base station selector 60 of the mobile communication system according to the second embodiment. The base stations 61 to 63 in FIG. 3 are arranged at substantially equal intervals on the boundary line of one cell, and the function for the cell and the adjacent cell is the first.
This corresponds to the base stations 31 to 33 of the embodiment.

In FIG. 3, base station 61 sequentially scans channel N allocated to this cell in the order of (1) to (N), for example, and receives a desired wave for power measurement. Machine 64.

The desired wave power measuring device 65 connected to the output terminal of the measuring receiver 64 is a device for measuring the desired wave power in the base station 61 of the channel that the measuring receiver 64 is receiving. The measurement result is supplied to the base station selection device 66.

Each of the communication receivers 67 to 68 for mediating communication between a mobile station in a cell and another terminal can switch its reception channel (X) in the range of channels (1) to (N). In the base station 61, M receivers having less than N channels are mounted.

The relationship between M and N is determined in consideration of the number of base stations covering the cell, the required communication quality, the utilization efficiency of equipment, and the like. This is the same as the relationship of N.

The switching range of the receiving channel (X) of each of the receivers 67 to 68 is not limited to the entire range of (1) to (N), but is set to (1) to (N) for the communication receivers of the M devices. May be set to be shared without duplication, may be set so as to be partially overlapped,
The sharing may be partially overlapped. Also, the receiver 67
A receiver of a fixed channel that cannot switch channels may be included as a part of the receivers -68.

The base station 61 includes M transmitters 69 to 70 having less than the number N of channels.
70 can switch the transmission channel in the entire range of (1) to (N).

Since the transmitters 69 to 70 communicate with the mobile stations together with the receivers 67 to 68, in this embodiment, the number of mounted transmitters is the same as the number of mounted receivers, and the channel switching range is the same as that of the receiver. It is.

Note that the receiving channel switching range of each of the transmitters 69 to 70 is not limited to the entire range of (1) to (N), and (1) to (N) are not duplicated by the M communication receivers. The points that may be set so as to be shared are the same as those of the receivers 67 to 68.

However, the number of receivers and the number of transmitters may be different if necessary.

The desired wave power measuring device 65 may be configured by applying the “interference detection method using sample values” described in the above-mentioned document 2 as in the first embodiment.

The base station 61 further includes a signal line 61A for transmitting information on the number of transmitters in the base station 61 not used for communication, ie, information on the number of vacant transmitters, to the base station selector 66.
It has.

In the base station 62, the measuring receiver 71 is a receiver equivalent to the above-described measuring receiver 64, the desired wave power measuring device 72 is equivalent to the desired wave power measuring device 65, and the receivers 73 to 74 are provided. Are equivalent to the receivers 67 to 68 and the transmitter 75
76 are equivalent to the transmitters 69 to 70, and the signal line 62A is equivalent to the signal line 61A, and therefore detailed description of each unit is omitted.

However, the number of receivers does not need to match between the base stations 61 and 62, and the number of transmitters does not need to match.

Similarly, in the base station 63, the measuring receiver 80 is a receiver equivalent to the above-described measuring receiver 64, and the desired wave power measuring device 81 is equivalent to the desired wave power measuring device 65. 82 to 83 are equivalent to the receivers 67 to 68, the transmitters 84 to 85 are equivalent to the transmitters 69 to 70,
Since 3A is equivalent to the signal line 61A, detailed description of each part is omitted.

The number of receivers does not need to match between the base stations 61 and 63, and the number of transmitters does not need to match.

When the number of communication receivers installed in the base station is smaller than the number of transmitters, the base station uses the number of empty receivers instead of the number of empty transmitters as signal lines (61A to 61A).
63A), the base station selection device 66 may be notified. Hereinafter, the operation of the second embodiment having the above configuration will be described.

(B-2) Operation of the Second Embodiment The desired wave that a certain mobile station in the cell is transmitting on channel (1) is the measuring receiver 64 that the base stations 61 to 63 are scanning. , 71, 80 are channel (1)
Are received by the measuring receivers 64, 71, and 80, respectively.

Then, the desired wave power measuring devices 65, 72, 81 connected to the respective receivers measure the power of the desired wave of the channel (1) at each base station, and transmit the measurement result to the base station selecting device 66. To supply.

Each of the base stations 61 to 63 is connected to the signal lines 61A to 61A.
Via 63A, data on the number of idle transmitters for each base station is transmitted to the base station selector 66.

Based on the number of empty transmitters, base station selecting device 66 determines that the number of empty transmitters among base stations 61 to 63 is zero.
If there is a base station that cannot transmit to the mobile station, the base station is excluded from candidates for selection. Now base station 3
It is assumed that the number of empty transmitters is not 0 in all of the cases 1 to 33.

The base station selecting device 38 determines the largest one of the three desired wave power measurement results supplied from each base station, and selects the base station that has provided the maximum desired wave power.

Assuming that this is base station 63, base station selector 66 selects any free receiver and free transmitter in base station 63, such as receiver 82 and transmitter 84, and sets these channels to ( Set to 1).

Thus, the mobile station can communicate with other terminals with good quality via the receiver 82 and the transmitter 84 of the base station 63.

While the mobile station and the receiver 82 and the transmitter 84 of the base station 63 are performing this communication,
Each measuring receiver 64, 71, 80 continues scanning,
If there is a desired wave of each channel of (1) to (N), the desired wave is received and the corresponding desired wave power measuring device power 65,
72 and 81 are output.

By this scanning, the measuring receiver 64,
If the reception channels 71 and 80 match (1) again,
The desired wave of the channel (1) is received again, and the power at each of the base stations 61, 62, 63 is measured by the desired wave power measuring devices 65, 72, 81.

At this time, when the mobile station moves, the base station that gives the maximum measurement result is transmitted from the base station 63 to the base station 6.
Suppose you changed to 2.

The base station selecting device 66, which recognizes that the number of vacant transmitters of the base station 62 is not 0, sends an vacant receiver and a vacant transmitter within the base station 62, for example, the receiver 73 and the transmitter. Select 75 and have these channels set to (1).

Thus, the mobile station can maintain communication quality with other terminals via the receiver 73 and the transmitter 75 of the base station 62.

Thereafter, similar operations are repeated as necessary.

(B-3) Effects of the Second Embodiment As described above, according to the second embodiment, although the frequency of measurement of the desired signal power for each channel can be reduced, the base station is compared with the related art. It is possible to reduce not only the number of transmitters mounted on the device but also the number of receivers, and it is possible to increase the use efficiency of the transmitter and the receiver in the operation state.

Further, since base station selection is performed in consideration of information on the number of vacant transmitters for each base station covering a common cell, the communication quality is reduced, if any, at all. The utilization efficiency of the machine is high.

(C) Third Embodiment Hereinafter, the uplink and downlink channels between the mobile station and the base station are defined as TD.
The third embodiment of the mobile communication system according to the present invention will be described with an example of multiplexing in the D system.

(C-1) Configuration and Operation of the Third Embodiment FIG. 4 is a schematic diagram of the base station selector 90 of the mobile communication system according to the third embodiment. The base stations 91 to 93 in FIG. 4 are arranged at substantially equal intervals on the boundary line of one cell, and the function for the cell and the adjacent cell is the first.
This corresponds to the base stations 31 to 33 of the embodiment.

The receivers 67 to 68 and 73 to 7 in FIG.
4, 82-83, transmitters 69-70, 75-76, 84
To 85 and the base station selection device 66 are respectively shown in FIG.
Correspond to the parts denoted by the same reference numerals, and have the same configuration and the same operation, and therefore detailed description thereof will be omitted.

In FIG. 4, the measuring receiver 94 of the base station 91 scans the channel N allocated to the cell and receives each desired wave for power measurement. The order and frequency of each channel are controlled by the measuring receiver control unit 95.

The desired wave power measuring device 96 connected to the output terminal of the measuring receiver 94 supplies the desired wave power as the measurement result to the base station selecting device 66 and the measuring receiver control unit 95. .

Upon receiving the supply of the desired wave power, the measurement receiver control unit 95 stores the desired wave power data for each channel for a necessary period, and the frequency of measurement for a channel whose desired wave power is in an intermediate predetermined range increases. Measurement receiver 94
To control scans.

A mobile station transmitting a desired wave of power in an intermediate predetermined range in each of the base stations 91 to 93 is a mobile station located at substantially the same distance from each base station in terms of propagation characteristics. It is a mobile station in which the base station that measures the maximum desired wave power with a small movement is replaced.

Therefore, there is a high possibility that communication quality cannot be maintained for such a desired wave from a mobile station unless power measurement is performed more frequently than for a desired wave from another mobile station. For this reason, in the present embodiment, the measurement receiver control unit 9
5, the scanning of the measuring receiver 94 is controlled so as to increase the frequency of measurement for channels in the intermediate predetermined range where the desired signal power is not too large or too small.

The base station 91 also has a signal line 9 for transmitting the number of idle transmitters (or the number of receivers) in the base station 91 to the base station selecting device 66, similarly to the base station 61 in FIG.
1A.

As in base station 91, base stations 92 and 93
, The measurement receivers 96 and 100 are equivalent to the above-described measurement receiver 94, the desired wave power measurement devices 97 and 101 are equivalent to the desired wave power measurement device 96, and the measurement receiver control units 98 and 102 are Since the signal lines 92A and 93A are equivalent to the signal line 91A and the signal lines 92A and 93A are equivalent to the measurement receiver control unit 95, detailed description thereof will be omitted.

The base station selecting section 90 thus configured
The three base stations 91 to 93 collectively increase the measurement frequency of the predetermined range of power for the desired wave, and maintain the communication quality between the mobile station in the cell and another terminal.

(C-2) Effect of Third Embodiment As described above, according to the third embodiment, the influence of the decrease in the frequency of measurement of the desired signal power for each channel in the second embodiment is reduced. Thus, an effect equivalent to that of the second embodiment can be obtained.

(D) Other Embodiments In the above description, each base station measures the power of the desired wave. However, in all of the first to third embodiments, the power of the desired wave is replaced by the power of the desired wave. The signal-to-interference power ratio may be measured, the signal-to-noise power ratio may be measured, the signal-to-interference noise power ratio may be measured, or the decision error power may be measured.

Further, in all of the first to third embodiments, among the five characteristics of the power of the desired wave, the signal to interference power ratio, the signal to noise power ratio, the signal to interference noise power ratio, and the decision error power, , A plurality of characteristics may be selected, and a base station may be selected based on the selected plurality of characteristics.

However, when measuring the above-mentioned determination error power, in all of the first to third embodiments, the base station selecting apparatus moves in the direction of selecting the base station having the minimum determination error power. Operate.

The decision error power is the power of the deviation generated between the sample value after synchronous detection and the decision value due to noise and interference, and a specific example of the measuring method is described in the aforementioned reference 2. In Reference 2, a determination value obtained by passing a sample value of a desired wave after synchronous detection through a determination unit and an error power value obtained from the sample value are temporally averaged to obtain this determination error power. I have.

In the second and third embodiments,
The measurement receiver may be omitted, and the M communication receiver may perform measurement.

In the above description, two-way communication between a certain mobile station and a base station in a cell is performed by TDD.
(Frequency Division Duplex), the present invention is also applicable.

That is, according to the present invention, from among a plurality of base stations provided with the number of receivers corresponding to the number of channels allocated to the cell, the desired wave transmitted by the mobile station is determined according to the reception characteristic at each base station. The present invention can be widely applied to a mobile communication system that selects a base station that communicates with the mobile station.

[0099]

As described above, according to the present invention, the utilization efficiency of devices such as base station transmitters per cell can be increased, and the number of devices can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a base station selection unit of a mobile communication system according to a first embodiment.

FIG. 2 is a block diagram illustrating a configuration of a base station selection unit of a conventional mobile communication system.

FIG. 3 is a block diagram illustrating a configuration of a base station selection unit of the mobile communication system according to the second embodiment.

FIG. 4 is a block diagram illustrating a configuration of a base station selection unit of a mobile communication system according to a third embodiment.

[Explanation of symbols]

1-3, 31-33, 61-63, 91-93 ... base stations, 10, 11, 34, 35, 67, 68 ... receivers, 1
2, 13, 36, 37, 65, 96 ... desired wave power measuring device, 14, 15, 39, 40, 69, 70 ... transmitter, 1
6, 38, 66 ... base station selection device, 31A to 33A, 6
1A to 63A, 91A to 93A ... signal lines, 64, 94 ...
Measurement receiver, 95, 98, 102... Measurement receiver controller, N... Number of channels.

Claims (12)

[Claims] 1. A mobile station, comprising: a plurality of base stations each having a number of receivers corresponding to the number of channels allocated to a cell; A mobile communication system for selecting a base station to communicate with a station, wherein the number of transmitters mounted on each base station is smaller than the number of channels. 2. The mobile communication system according to claim 1, wherein a transmission channel of the transmitter is variable. 3. The mobile communication system according to claim 1, wherein the receiver includes a measurement receiver used to switch a reception channel and measure the reception characteristics of each reception channel. Characteristic mobile communication system. 4. The mobile communication system according to claim 1, wherein the receiver includes less than the number of channels for switching a reception channel for communication of a mobile station. Mobile communication system. 5. The mobile communication system according to claim 3, wherein the switching of the reception channel for measuring the reception characteristic is performed for a reception channel whose measured value of the reception characteristic is in an intermediate predetermined range. A mobile communication system characterized in that measurement is performed so as to increase the frequency of characteristic measurement. 6. The mobile communication system according to claim 1, wherein, when selecting the base station, among the transmitters provided in each base station, the transmitter is not used at the time of the base station selection. A mobile communication system, wherein the number of transmitters is used as a selection criterion having a higher priority than the reception characteristics. 7. The mobile communication system according to claim 1, wherein the reception characteristic is the power of the desired wave. 8. The mobile communication system according to claim 1, wherein the reception characteristic is a signal-to-interference power ratio of the desired wave. 9. The mobile communication system according to claim 1, wherein the reception characteristic is a signal-to-noise power ratio of the desired wave. 10. The mobile communication system according to claim 1, wherein the reception characteristic is a signal-to-interference noise power ratio of the desired wave. 11. The mobile communication system according to claim 1, wherein the reception characteristic is a determination error power of the desired wave. 12. The mobile communication system according to any one of claims 1 to 6, wherein the reception characteristics are power for the desired wave, a signal to interference power ratio, a signal to noise power ratio, a signal to interference noise power ratio,
A mobile communication system characterized by having a plurality of characteristics selected from the determination error power.