JP2003018641A - Cellular system, adjacent frequency interference evading method therefor, mobile station and base station control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an increment of adjacent frequency interference power due to an increase in a frequency switching rate of adjacent frequency interference evading control, and to suppress an increment of a control load of frequency switching due to the increase in the frequency switching rate of the adjacent frequency interference evading control. SOLUTION: In a method for evading adjacent frequency interference, a mobile station 20 measures received power of downlink signals from base stations 30 and 31 of the cellular system to which the station 20 belongs, and received power of a downlink signal from a base station 40 of another cellular system respectively, and switches a frequency band used by the station 20 if a ratio of both the results is equal to or more than a prescribed judgment threshold value. In this method, the measured result of the received power of the downlink signals from the stations 30 and 31 is corrected by using information about the received power of perch channels 62 and 65 transmitted from the base stations. Further, the judgment threshold value is corrected by channel connection information of the station 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for avoiding adjacent frequency interference in a cellular system, a cellular system, a mobile station, and a base station controller.

[0002]

2. Description of the Related Art In a cellular system using a code division multiple access system, transmission power control is performed in order to increase the line capacity. Usually, the transmission power control is performed using the value of the signal power to interference power ratio (SIR) expressed by the following equation. SIR = S / (I + N) (1) where S is the desired signal power, I is the interference power per band, and N is the noise power per band. In the transmission power control, the reception side measures the reception SIR in the above formula (1). If the measurement result is smaller than the target SIR, the transmission side is instructed to increase the transmission power, and if it is larger, the transmission side is instructed. By instructing the transmission power to be reduced, it becomes possible to control the line quality to be constant and to increase the line capacity.

Further, in a cellular system using the code division multiple access system, a soft handover technique in which a mobile station connects to a plurality of base stations simultaneously is important. The soft handover technique is that the mobile station periodically observes the received power of the perch channels transmitted from the base stations of its own cell and adjacent cells, and the maximum value of the received power of these perch channels is used as a reference. By connecting a line with a base station that transmitted a perch channel that is within a certain threshold (hereinafter, this threshold will be referred to as an active set threshold) from this maximum value, it is possible to connect lines with multiple base stations at the same time. is there.

When the mobile station is located near the base station,
Since the propagation loss between the mobile station and the base station located in the vicinity is sufficiently smaller than the propagation loss for the base station in the adjacent cell, the received power of the perch channel transmitted from the base station located in the vicinity of the mobile station is maximized. Therefore, the difference between this received power and the received power of the perch channel from the base station in the adjacent cell is larger than the active set threshold. Therefore,
The line is connected only to the base station located near the mobile station.

On the other hand, when the mobile station is located near the cell edge, the propagation loss with respect to the base stations of the own cell and the adjacent cell is almost the same, so the perch received by the mobile station from the base stations of the own cell and the adjacent cell. The difference in channel power is small. Therefore, a plurality of perch channels within the active set threshold are received, and as a result, the lines are simultaneously connected to the plurality of base stations.

By using the soft handover technique described above, even when the mobile station is moving between its own cell and an adjacent cell, non-interruption of the line can be achieved.

However, in the above-mentioned cellular system using the code division multiplexing method, when a plurality of cellular systems coexist in the same service area and these cellular systems use adjacent frequency bands, There may be a problem that the line quality deteriorates due to adjacent frequency interference.

Here, the adjacent frequency interference refers to a phenomenon in which electric power in a frequency band adjacent to a frequency band connecting a line leaks into a frequency band connecting the line, and the line is connected by the adjacent frequency interference. The line quality in the current frequency band deteriorates. On the transmission side, the cause of the adjacent frequency interference is mainly the leakage of the transmission spectrum into the adjacent frequency band due to the nonlinearity of the transmission amplifier. On the other hand, on the receiving side, the reception filter may receive adjacent frequency band signals.

The adjacent frequency interference problem will be described below from the viewpoint of system configuration. FIG. 1 is a diagram showing a case where two cellular systems coexist in the same service area, and FIG. 2 is a diagram showing carrier arrangements of uplink and downlink of the cellular system shown in FIG. In FIG. 1, a base station 30 and a base station 31 belong to one cellular system, and a mobile station 20 belonging to one cellular system can connect a line to the base station 30 and the base station 31,
The carriers used by this line are assumed to use the carrier 102 and the carrier 105 for the uplink and the downlink in FIG. 2, respectively. A cell 91 indicates a service area of the base station 30, and a cell 92 indicates a service area of the base station 31. The base station 40 and the mobile station 50 belong to the other cellular system. The base station 40 connects a line to the mobile station 50, and the carrier used by this line uses the carrier 101 and the carrier 104 in the uplink and the downlink in FIG. 2, respectively.

As shown in FIG. 1, while the mobile station 20 is located near the base station 40 of another cellular system, the base station 3
When 0 is connected to the line, the mobile station 20 transmits a large amount of transmission power in the uplink so that the distant base station 30 can receive it with a constant line quality. A large adjacent frequency interference power is given to the base station 40. As a result, the line quality of the uplink between the base station 40 and the mobile station 50 connecting the line is deteriorated. On the other hand, in the downlink, the transmission power of the base station 40 gives a large adjacent frequency interference to the mobile station 20 located in the vicinity of the base station 40, and therefore the downlink line between the mobile station 20 and the base station 30. Deteriorate quality.

As a technique for avoiding this adjacent frequency interference, Japanese Unexamined Patent Publication No. 11-341555 discloses a method of switching carriers to be used. In the adjacent frequency interference avoidance method disclosed in the above publication, first, in FIG.
In, the mobile station 20 receives the received power Pc of the downlink carrier 105 transmitted from the base station 30 and the base station 31.
o and the received power Padj of the downlink carrier 104 transmitted from the base station 40 are measured, and the following equation (2)
These ratios X are calculated based on X = Padj / Pco (2)

Then, the mobile station 20 judges the magnitude of the obtained X value with respect to the preset threshold value Th_u of the adjacent frequency interference avoidance control for the uplink and the preset threshold value Th_d of the adjacent frequency interference avoidance control for the downlink. . As a result, when the X value is equal to or larger than the determination threshold Th_u for the adjacent frequency interference avoidance control in the uplink, the transmission power of the mobile station 20 is the uplink carrier 1 used by the base station 40.
01, the mobile station 20 starts control of avoiding adjacent frequency interference for the uplink, and the base station 40 adjacent frequency interference for the carrier 101 used by the uplink. In order to reduce the carrier, the base station 30 and the mobile station 20 perform frequency switching from the carrier 102 to the carrier 103 in order to separate the carrier used in the uplink from the carrier 101.

When the X value is equal to or larger than the determination threshold value Th_d for the adjacent frequency interference avoidance control in the downlink, the transmission power from the base station 40 has an influence on the downlink carrier 105 used by the mobile station 20. It is determined that the adjacent frequency interference is exerted to such an extent that the control for avoiding the adjacent frequency interference for the downlink in the mobile station 20 is started, and the mobile station 2
Carrier 0 used by the mobile station 20 in the downlink in order to reduce the adjacent frequency interference that 0 receives from the base station 40.
In order to separate the carrier 5 from the carrier 104, the carrier 106 is frequency-switched.

[0014]

However, the adjacent frequency interference avoidance method in the above-mentioned conventional technique has the following four problems.

(1) In the uplink, the adjacent frequency interference power received by the base station 40 from the mobile station 20 is the mobile station 2
It is determined by the transmission power of 0. Here, the transmission power of the mobile station 20 depends on the interference power received by the base station 30 that connects the line to the mobile station 20. In order for the mobile station 20 to estimate this interference power, it is desirable to observe the reception power value Pco1 of the carrier 105 transmitted from the base station 30, but the value of Pco received by the mobile station 20 is other than Pco1. In addition, the reception power Pco2 of the carrier 105 transmitted from the base station 31 is also included. Here, Pco2 does not depend on the transmission power of the mobile station 20. Therefore, in the conventional technique, Pco in the equation (2) is a value increased by Pco2 that does not affect the transmission power of the mobile station 20, and thus when the determination threshold Th_u is fixed,
The number of Padj possessed by the judgment threshold Th_u increases. Therefore, if the ratio of Pco2 to Pco increases, the frequency switching probability due to the adjacent frequency interference avoidance control decreases, and the adjacent frequency interference received by the mobile station 20 increases. As a result, the mobile station 20 gives the base station 40 an extra adjacent frequency interference power according to the decrease in the frequency switching probability, so that the line quality of the uplink of the base station 40 deteriorates.

(2) In the downlink, the adjacent frequency interference power received by the mobile station 20 from the base station 40 is the mobile station 2
0 depends on the interference power given to the mobile station 20 by the carrier 105 transmitted from the base station 30 that connects the line with 0. In order to estimate this interference power at the mobile station 20, the base station 3
Received power value Pco1 of carrier 105 transmitted from 0
Is desired to be observed, but P received by the mobile station 20
The value of co includes the reception power Pco2 of the carrier 105 transmitted from the base station 31 in addition to Pco1. Here, Pco2 gives the same frequency interference to the mobile station 20. Therefore, in the conventional technique, the Pco in equation (2) is the Pco received by the mobile station 20.
Since the same-frequency interference power has a value increased by two, the determination threshold Th_d is fixed when the determination threshold Th_d is fixed.
The Padj possessed by the value of d increases. Therefore, when the ratio of Pco2 to Pco increases, the frequency switching probability due to the adjacent frequency interference avoidance control decreases,
The adjacent frequency interference that the mobile station 20 receives from the base station 40 increases. As a result, the mobile station 20 is
As a result, excess adjacent frequency interference power corresponding to the decrease in the frequency switching probability is received, so the line quality of the downlink of the mobile station 20 deteriorates.

(3) In FIG. 1, when the mobile station 20 is executing a soft handover with the base station 30 and the base station 31, in the uplink, the mobile station 2 is affected by the diversity effect.
The transmission power of 0 is reduced as compared with the case where the mobile station 20 is not executing the soft handover. Therefore, the adjacent frequency interference power given to the base station 40 is reduced. In the conventional technique, the determination threshold T depends on the presence or absence of the diversity effect.
Since h_u is not corrected, the adjacent frequency interference received before the mobile station 20 performs frequency switching for avoiding adjacent frequency interference is reduced. Therefore, the frequency switching probability of the adjacent frequency interference avoidance control is higher than that in the case where there is no diversity effect, and as a result, the frequency switching control load is increased.

(4) In FIG. 1, when the mobile station 20 is executing a soft handover with the base station 30 and the base station 31, in the downlink, due to the diversity effect, the base station 3
0, and the transmission power of the base station 31 is less than that of the case where the mobile station 20 is not executing the soft handover.
Since the interference due to 5 decreases, the adjacent frequency interference power receivable from the base station 40 can be increased accordingly. However, in the conventional technique, the determination threshold Th_d is not corrected depending on the presence or absence of the diversity effect, so that the adjacent frequency interference power received before the mobile station 20 performs the frequency switching for avoiding the adjacent frequency interference is reduced. . Therefore, the frequency switching probability of the adjacent frequency interference avoidance control is higher than that in the state in which there is no diversity effect, and as a result, the control load of frequency switching is increased.

[0019]

It is an object of the present invention to suppress an increase in adjacent frequency interference power caused by a decrease in frequency switching probability of adjacent frequency interference avoidance control, and to perform frequency switching by increasing frequency switching probability due to adjacent frequency interference avoidance control. An object of the present invention is to provide a method for avoiding adjacent frequency interference that suppresses an increase in control load.

[0020]

In order to solve the above-mentioned problems, a method for avoiding adjacent frequency interference in a cellular system according to the present invention is a mobile station that constitutes one cellular system, in which a base station of the other cellular system is used. While measuring the received power of the transmitted signal, the received power of the signal transmitted from the base station of one cellular system is measured, if the ratio of both received power is equal to or more than a predetermined determination threshold, the mobile station The frequency band is switched so that the frequency band used by the uplink is separated from the frequency band of the uplink used by the other cellular system, or the frequency band used by the mobile station in the downlink is the downlink used by the other cellular system. A method for avoiding adjacent frequency interference in a cellular system that switches a frequency band so as to be separated from the frequency band of
It is characterized in that the measurement result of the reception power of the signal transmitted from the base station of one cellular system is corrected by using the information about the reception power of the perch channel transmitted from the base station of one cellular system. Also, the mobile station
It is characterized in that the judgment threshold value is corrected using the line connection information of the mobile station.

In the method for avoiding adjacent frequency interference in a cellular system according to the present invention, the value of Pco in the above equation (2) (measurement result of received power of a signal transmitted from a base station of one cellular system) is used as a mobile station. In, the correction is performed using the information about the reception power of the perch channel transmitted from a plurality of base stations. Further, by using the line connection information of the mobile station, control determination thresholds Th_u and T for avoiding adjacent frequency interference
Correct h_d. This suppresses an increase in adjacent frequency interference power caused by a decrease in frequency switching probability of adjacent frequency interference avoidance control, and an increase in frequency switching control load due to an increase in frequency switching probability due to adjacent frequency interference avoidance control. You can

The mobile station measures the reception power of the signal transmitted from the base station of the other cellular system, measures the reception power of the signal transmitted from the base station of one cellular system, and The base station controller is notified of the information about the reception power of the perch channel transmitted from the base station of the cellular system, and the base station controller side calculates the value of Pco in the above formula (2) (from the base station of one cellular system). The measurement result of the received power of the transmitted signal) may be corrected, and the base station controller may correct the control determination thresholds Th_u and Th_d for avoiding adjacent frequency interference.

The cellular system according to the present invention measures the reception power of the transmission signal transmitted from the base station of the other cellular system in the mobile station which constitutes one cellular system, and When the reception power of the transmission signal transmitted from the base station is measured and the ratio of the measurement results of both reception powers is greater than or equal to a predetermined threshold, the frequency band used by the mobile station in the uplink is determined by the other cellular system. A cellular that switches the frequency band so that it is separated from the frequency band of the uplink used, or a frequency band that switches the frequency band used by the mobile station in the downlink from the frequency band of the downlink used by the other cellular system. In the system, the mobile station measures the reception power of the transmission signal transmitted from the base station of one cellular system by And correcting using information on received power of the perch channel transmitted from the base station Lula system. Further, the mobile station is characterized in that the determination threshold is corrected using the line connection information of the mobile station.

In the cellular system according to the present invention, the value of Pco in the above equation (2) (measurement result of the received power of the signal transmitted from the base station of one cellular system) is used by a plurality of base stations in the mobile station. It is corrected by using the information about the received power of the perch channel transmitted from. Also, the control determination thresholds Th_u and Th_d for avoiding adjacent frequency interference are corrected using the line connection information of the mobile station.
This suppresses an increase in adjacent frequency interference power caused by a decrease in frequency switching probability of adjacent frequency interference avoidance control, and an increase in frequency switching control load due to an increase in frequency switching probability due to adjacent frequency interference avoidance control. You can

The mobile station measures the reception power of the signal transmitted from the base station of the other cellular system, measures the reception power of the signal transmitted from the base station of one cellular system, and The base station controller is notified of the information about the reception power of the perch channel transmitted from the base station of the cellular system, and the base station controller side calculates the value of Pco in the above formula (2) (from the base station of one cellular system). The measurement result of the received power of the transmitted signal) may be corrected, and the base station controller may correct the control determination thresholds Th_u and Th_d for avoiding adjacent frequency interference.

The mobile station according to the present invention comprises means for measuring the received power of the downlink carrier used by the mobile station for connecting the line, and the downlink carrier and frequency used by the mobile station for connecting the line. A means to measure the received power of the downlink carrier adjacent on the axis, a means to measure the information about the received power of the perch channel transmitted from multiple base stations, and used by the mobile station to connect the line. Means for correcting the measurement result of the received power of the downlink carrier using the information about the received power of the perch channel transmitted from a plurality of base stations, and the result of the correction and the mobile station to use in the connection of the line A means for performing threshold judgment using the downlink carrier and the measurement result of the received power of the downlink carrier adjacent on the frequency axis, a means for observing mobile station line connection information, and a threshold judgment. Means for correcting using the line connection information threshold used during one in which the mobile station based on the result of the threshold determination is provided means for performing a carrier change control circuit to use.

The base station control device according to the present invention is a means for receiving the measurement result of the received power of the carrier of the downlink used by the mobile station for connecting the line, and the downlink used by the mobile station for connecting the line. A means for receiving the measurement result of the reception power of the downlink carrier adjacent to the line carrier on the frequency axis, and a means for receiving the measurement result of the information about the reception power of the perch channel transmitted from a plurality of base stations. When,
A means for correcting the measurement result of the reception power of the downlink carrier used by the mobile station for connection of the line by using the measurement result of the reception power of the perch channel transmitted from a plurality of base stations; Means for performing threshold judgment using the result and the measurement result of the received power of the downlink carrier used by the mobile station for connecting the line and the downlink carrier adjacent on the frequency axis, and the line connection information of the mobile station. Means for observing the threshold value, means for correcting the threshold value used in the threshold value judgment using the line connection information, and means for controlling the change of the carrier of the line used by the mobile station based on the result of the threshold value judgment. It is provided.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of a cellular system according to the first embodiment of the present invention. In FIG. 1, the mobile station 20 individually receives information about the perch channel 62 and the perch channel 65 with respect to the base station 30 and the base station 31. Here, for example, in the mobile station 20, the reception power of the perch channel 62 is P_a and the reception power of the perch channel 65 is P_b. In the first embodiment of the present invention, the Pco value shown in equation (2) is corrected as in the following equation. Pco (after correction) = C · Pco (3) Here, Pco (after correction) is the value after correction of Pco. Further, C is a correction coefficient.

Pco in the above equation (3) (after correction)
Is the carrier 10 received from the base station with the best communication condition (base station with the maximum received power of the perch channel).
It is obtained by correcting the power of 5 from Pco. Here, the correction coefficient C of the equation (3) is expressed by the following equation. C = max (P_a, P_b) / (P_a + P_b) (3) Here, max () is a function for extracting the maximum value among the numerical values in (). For example, when P_a> P_b Is max (P_a, P_b) = P_a, and P_b
When> P_a, max (P_a, P_b) = P_b.

Further, assuming that the number of perch channels that this mobile station can receive is N, the correction coefficient C in the equation (3) is generalized by the following equation. C = max (P_1, ..., P_N) / (ΣP_i) (i = 1, 2, ..., N) (4)

Using the above correction coefficient C, the X value of the equation (2) used in the adjacent frequency interference avoidance control is rewritten by the following equation. X = Padj / Pco (after correction) = Padj / (C * Pco) (5)

By using the X value of the equation (5), it is possible to suppress the increase in the adjacent frequency interference power caused by the decrease in the frequency switching probability of the adjacent frequency interference avoidance control.

The correction using the information about the reception power of the perch channel is equivalent to the control determination thresholds Th_u and Th_d instead of Pco.

Further, in FIG. 1, when the mobile station 20 is in the line connection state with the base station 30 and the base station 31 (when executing the soft handover), due to the diversity effect,
In the uplink, the mobile station 20 can reduce the transmission power for the base station 30 and the base station 31. Therefore, as for the transmission power of the mobile station 20, the adjacent frequency interference power given to the base station 40 is reduced as compared with the case where the diversity effect is not used.

Therefore, by correcting the determination threshold Th_u of the adjacent frequency interference avoidance control in the uplink in accordance with the diversity gain, it is possible to reduce the probability of frequency switching by the adjacent frequency interference avoidance control and reduce the control load. . On the other hand, in the downlink as well,
By using the diversity effect, the power transmitted by the base station 30 and the base station 31 to the mobile station 20 can be reduced. Therefore, compared with the case where the diversity effect is not used, Pco in the equation (2) decreases, but the value of the adjacent frequency interference power Padj received before the frequency switching by the adjacent frequency interference avoidance control is started does not change. . Therefore, by correcting the determination threshold Th_d of the adjacent frequency interference avoidance control in the downlink according to the diversity gain, it is possible to reduce the probability of frequency switching by the adjacent frequency interference avoidance control and reduce the control load.

In the uplink and downlink, the amount of transmission power reduction due to the diversity effect depends on the diversity gain, which depends on the diversity scheme (maximum ratio combining, selective combining, etc.) and the number of diversity branches. From the above, the diversity gain in the uplink is
Assuming iv_up, the control determination threshold Th_u for avoiding adjacent frequency interference in the uplink can be corrected by the following equation to reduce the probability of frequency switching due to adjacent frequency interference avoidance control and reduce the control load. Th_u (after correction) = Th_u (before correction) · Gdiv_up (6) where Th_u (before correction) is the diversity gain Gdi
represents the control determination threshold value Th_u before correction with v_up,
Th_u (after correction) is the control determination threshold Th after Th_u (before correction) is corrected with the diversity gain Gdiv_up.
Represents _u.

On the other hand, similarly for the downlink, assuming that the diversity gain in the downlink is Gdiv_down, the adjacent frequency interference avoidance control is performed for the adjacent frequency interference avoidance control by correcting the adjacent frequency interference avoidance control determination threshold Th_d in the downlink. It is possible to reduce the frequency of frequency switching by and reduce the control load. Th_d (after correction) = Th_d (before correction) · Gdiv_down (7) where Th_d (before correction) is the diversity gain Gdi
The control determination threshold Th_d before being corrected by v_down represents Th_d (after correction), and the control determination threshold Th_d after correcting Th_d (before correction) by the diversity gain Gdiv_down.

The correction considering the diversity gain is equivalent to Pco instead of the control determination thresholds Th_u and Th_d.

FIG. 3 is a block diagram of the cellular system in the embodiment of the present invention. In FIG. 3, base stations 501 to
503 is installed in each of the cells 511 to 513, and connects the lines with the mobile stations 520 and 521 in the own cell. The base station control device 530 uses the base stations 501 to 50.
Control 3 The base stations 501 to 503 transmit a perch channel that transmits with common transmission power and a communication channel that transmits individually to mobile stations that connect the lines. The communication channel for the mobile stations 520 and 521 is the mobile station 52.
The transmission power is controlled so that the reception quality becomes constant at 0,521. The mobile stations 520 and 521 are the base stations 50.
The perch channels transmitted from 1 to 503 are periodically measured to determine the base station to set the line. The line is set between the base station having the best reception quality and the base station in which the difference in reception quality between the base station and the base station is within the active set threshold.

FIG. 4 is a block diagram of a base station controller in the first embodiment of the present invention, and FIG. 5 is the first embodiment of the present invention.
6 is a block configuration diagram of a base station according to the embodiment of the present invention, and FIG. 6 is a block configuration diagram of a mobile station according to the first embodiment of the present invention.

As shown in FIG. 4, the base station controller 600
Is an input terminal 601 for receiving signals from one or more base stations, and a reception processing unit 602 for processing received signals.
A control unit 603 that performs control based on a control signal from a mobile station or a base station, a transmission processing unit 604, and an output terminal 605 that transmits a signal to one or more base stations.

The control unit 603 receives a control signal for requesting frequency switching for adjacent frequency interference avoidance control from the mobile station, and transmits a frequency switching control signal to a base station in a line connection with the mobile station. The control unit 603 controls the channel setting between the mobile station and the base station.

As shown in FIG. 5, the base station 700 includes an antenna 701 for transmitting / receiving signals to / from one or more mobile stations, a transmission / reception duplexer 702 for high-frequency processing of transmission signals and reception signals, and a baseband. A reception processing unit 703 that performs signal reception processing, a control unit 704 that performs control using information from an input terminal 711 that receives a control signal transmitted from the reception processing unit 703 and the base station controller 600,
An output terminal 710 for transmitting control information in the control unit 704 to the base station control device 600, an output terminal 705 for outputting reception data, an input terminal 706 for receiving transmission data,
A multiplexer (MU) that combines transmission data and control signals
X) 707 and a transmission processing unit 708 that performs baseband processing of transmission data.

The transmission / reception duplexer 702 receives a frequency switching control signal from the control unit 704, and performs frequency switching used for transmission or reception. The control unit 704 measures the reception quality by the reception processing unit 703 and controls the transmission power for the mobile station. The control unit 704 includes the base station control device 6
The transmission / reception control of the base station is performed based on the control signal received from 00. The control unit 704 receives a control signal for frequency switching for avoiding adjacent frequency interference received from the base station control device 600, and transmits a control signal for transmission or switching of a frequency used for reception to the transmission / reception duplexer 702.

As shown in FIG. 6, the mobile station 800 includes an antenna 801 for transmitting / receiving signals to / from one or a plurality of base stations, a transmission / reception duplexer 802 for high-frequency processing of transmission signals and reception signals, and a baseband. A reception processing unit 803 that performs signal reception processing, and an output terminal 8 that outputs transmission data
05, a control unit 804 that performs control based on the control signal from the reception processing unit 803 and the control signal from the adjacent frequency interference avoidance control unit 809, an input terminal 806 that receives transmission data, and a transmission from the control unit 804. A multiplexer (MUX) 807 for synthesizing the control signal and the transmission data input from the input terminal 806, and a transmission processing unit 808 for performing the baseband processing of the transmission data.

The control unit 804 periodically measures the perch channel transmitted from the base station by the reception processing unit 803, and selects the base station to which the line is connected based on these reception qualities. Also, it performs a process for transmitting information regarding line connection to the base station control device 600. The control unit 804 measures the reception quality by the reception processing unit 803 and generates a transmission power control signal for one or a plurality of base stations. The control unit 804 performs transmission power control based on the control information received from one or more base stations.

The adjacent frequency interference avoidance control unit 809 receives a control signal for adjacent frequency interference avoidance control from the control unit 804, and performs adjacent frequency interference avoidance control based on the control signal. The adjacent frequency interference avoidance control unit 809 controls the control unit 8
The reception power of the downlink carrier designated by 04 is measured from the transmission / reception duplexer 802. The adjacent frequency interference avoidance control unit 809 receives information about the reception power of the perch channel received by the mobile station from the control unit 804. The adjacent frequency interference avoidance control unit 809 receives information regarding the connection state of the line from the control unit 804.

The adjacent frequency interference avoidance control unit 809 calculates the X value of the equation (5), determines the magnitude relationship between this X value and the adjacent frequency interference avoidance control determination thresholds Th_u and Th_d, and the X value is determined. Adjacent frequency interference avoidance control determination threshold T
In the case of h_u and Th_d or more, a control signal for switching the carrier used by the mobile station is generated, and this control signal is transmitted to the control unit 804. Transmitter / receiver 802
Receives a control signal for frequency switching under transmission / reception control received from the control unit 804, and performs frequency switching for transmission or reception. Thus, the operation that forms the basis of the first embodiment of the present invention is performed by the adjacent frequency interference control unit 8
It will take place at 09.

FIG. 7 is a flow chart showing the operation of the first embodiment of the present invention. Hereinafter, the operation of the control in the adjacent frequency interference avoidance control unit 809 will be described with reference to FIG. 7.
When the operation of the adjacent frequency interference avoidance control unit 809 is started, the mobile station 800 measures the information about the reception power of all the perch channels that can be received by the carrier connecting the base station and the line (step S150). ). After that, the correction coefficient C in the equation (4) is calculated using the obtained information about the reception powers of all the perch channels (step S151).

Next, in order to correct the control determination threshold for avoiding adjacent frequency interference due to the diversity effect, it is detected whether or not the mobile station is executing soft handover (step S152). If the mobile station is executing the soft handover (YES in step S152), the diversity method is detected (step S153). In step S153, for example, if the diversity method is maximum ratio combining (maximum ratio combining in step S153), the correction coefficients Gdiv_up and Gdiv_do according to the diversity method are used.
wn is set, and a control determination threshold Th for avoiding adjacent frequency interference is set.
_U and Th_d are corrected based on equations (6) and (7), respectively (step S154). In step S153, if the diversity method is selective combining (step S1
The same applies to (selective combination in 53).

Although FIG. 7 shows two cases of maximum ratio combining and selective combining as diversity methods, it is important that these are determined by the diversity gain between the base station and the mobile station. Therefore, it is also effective to perform correction according to the number of diversity branches, for example.

Step S154 or step S155
After correcting the determination threshold of the adjacent frequency interference avoidance control with respect to the diversity effect, the X value in the equation (5) is calculated by the adjacent frequency interference avoidance control determination (step S156), and the X value and the adjacent frequency interference avoidance control are calculated. Determination threshold Th_u
And Th_d are compared to determine the frequency switching for avoiding adjacent frequency interference.

On the other hand, when the soft handover is not being executed (NO in step S152), the adjacent frequency interference avoidance control determination is performed without correcting the adjacent frequency interference avoidance control determination threshold value due to the diversity effect (step S156).
To calculate the X value in equation (5), and calculate the X value and Th_
By comparing u and Th_d, the frequency switching determination for avoiding adjacent frequency interference is performed.

Although FIG. 7 shows an example in which the diversity gain is used as the connection information of the line, the correction may be made by using the connection information of the line other than the diversity gain.

As described above, when the adjacent frequency interference control unit 809 determines the frequency switching by the adjacent frequency interference avoidance control, the information about the frequency switching is notified to the base station control device 600, and the line used by the mobile station is notified. Frequency switching control is performed.

Next, the second embodiment will be described below. The only difference between the second embodiment and the first embodiment is the difference between whether the threshold determination for adjacent frequency interference avoidance control is performed by the mobile station or the base station control device.

FIG. 8 is a block diagram of a base station control device according to the second embodiment of the present invention, and FIG. 9 is a second block diagram of the present invention.
3 is a block configuration diagram of a mobile station in the embodiment of FIG.
It should be noted that parts corresponding to those in FIGS. 4 and 6 are denoted by the same reference numerals, and redundant description will be omitted. The cellular system in which this embodiment is used is the same as that in FIG. The base station used in this embodiment is the same as that in FIG.

In FIG. 8, the control unit 611 receives the reception power Pco of the perch channel observed by the mobile station and the reception power Padj of the carrier measured by the adjacent frequency interference avoidance control from the reception processing unit 602. Control unit 61
1 receives a control signal for avoiding adjacent frequency interference from the adjacent frequency interference avoidance control unit 612.

The adjacent frequency interference avoidance control unit 612 receives from the control unit 611 information about the received power of the perch channel measured by the mobile station and the received powers Pco and Padj of the carriers measured by the adjacent frequency interference avoidance control. The adjacent frequency interference avoidance control unit 612 uses the information about the reception power of the perch channel measured by the mobile station and the reception results of the carrier reception powers Pco and Padj measured by the adjacent frequency interference avoidance control, and uses Expression (5).
The X value based on is calculated, and the threshold value for adjacent frequency interference avoidance control is determined. The adjacent frequency interference avoidance control unit 612 transmits the threshold value determination result of the adjacent frequency interference avoidance control to the control unit 611.

In FIG. 9, the transmission / reception duplexer 802 receives the frequency switching control signal from the control unit 811, and switches the frequency used by the mobile station 820 for transmission or reception. The carrier power measuring unit 810 receives a control signal for the carrier for which power measurement is performed from the control unit 811. The carrier power measuring unit 810 receives a control signal for the carrier whose power is to be measured from the control unit 811, and the transmission / reception duplexer 802 measures the received power of the carrier based on the control signal. Carrier power measuring unit 810
Transmits the measured power value of the carrier to the control unit 811.

The control unit 811 performs processing for transmitting the carrier reception power value received from the carrier power measurement unit and the information about the reception power of the perch channel received by the mobile station 820 to the base station control device 620. . Control unit 8
11 receives the frequency switching control received from the reception processing unit 803, and based on the control signal, the transmission / reception duplexer 802.
A control signal for frequency switching is transmitted to.

The operation that forms the basis of the second practical form of the present invention is performed by the adjacent frequency avoidance control unit 612. Adjacent frequency interference avoidance control unit 6 in base station controller 620
The flowchart regarding the operation of 12 is the same as that of FIG. 7.

Then, when the adjacent frequency interference control unit 612 determines that the frequency switching is performed by the adjacent frequency interference avoidance control, the information about the frequency switching is notified to the control unit 611 and the frequency switching of the line used by the mobile station is performed. Is controlled.

[0065]

As described above, according to the present invention, the increment of the adjacent frequency interference power caused by the decrease in the frequency switching probability of the adjacent frequency interference avoidance control is suppressed, and
It is possible to suppress an increase in control load of frequency switching due to an increase in frequency switching probability due to adjacent frequency interference avoidance control.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a cellular system according to a first embodiment of the present invention, and is a diagram showing a case where two cellular systems coexist in the same service area.

FIG. 2 is a diagram showing carrier arrangements of uplink and downlink of the cellular system shown in FIG.

FIG. 3 is a configuration diagram of a cellular system according to the first embodiment of the present invention.

FIG. 4 is a block configuration diagram of a base station control device according to the first embodiment of the present invention.

FIG. 5 is a block configuration diagram of a base station according to the first embodiment of the present invention.

FIG. 6 is a block configuration diagram of a mobile station according to the first embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of the first exemplary embodiment of the present invention.

FIG. 8 is a block configuration diagram of a base station control device according to a second embodiment of the present invention.

FIG. 9 is a block configuration diagram of a mobile station according to the second embodiment of the present invention.

[Explanation of symbols]

20,50,520,521,800,820 Mobile station 30, 31, 40, 700 base stations 61, 64, 71, 81 Downlink carrier power 63, 66, 72, 83 Uplink carrier power 62,65,82 perch channels 91, 92, 511, 512, 513 cells 101-106 carriers 530, 600, 620 Base station control device 601, 706, 711, 806 input terminals Output terminals 605, 705, 710, 805 602, 703, 803 Reception processing unit 604, 708, 808 Transmission processing unit 603, 611, 704, 804, 811 control unit 701,801 Transmission and reception antenna 702, 802 duplex transmitter / receiver 707,807 Multiplexer (MUX) 612,809 Adjacent frequency interference avoidance control unit 810 Carrier power measurement unit

Claims (18)

[Claims] 1. A mobile station constituting one cellular system measures received power of a transmission signal transmitted from a base station of the other cellular system, and transmits the transmission signal from the base station of one cellular system. The received power of the signal is measured, and when the ratio of the both measurement results is equal to or greater than a predetermined determination threshold, the frequency band used by the mobile station in the uplink is the frequency band of the uplink used by the other cellular system. In a method of avoiding adjacent frequency interference in a cellular system, the frequency band is switched to separate, or the frequency band used by the mobile station in the downlink is switched to separate the frequency band from the frequency band of the downlink used by the other cellular system. The mobile station uses the measurement result of the reception power of the transmission signal transmitted from the base station of one cellular system as the base of one cellular system. Adjacent frequency interference avoiding method for cellular system and correcting using information on received power of the perch channel is transmitted from the station. 2. The method for avoiding adjacent frequency interference in a cellular system according to claim 1, wherein the mobile station corrects the determination threshold value using line connection information of the mobile station. 3. A mobile station constituting one cellular system measures the reception power of a transmission signal transmitted from a base station of the other cellular system, and transmits the transmission signal from the base station of one cellular system. The received power of the signal is measured, and when the ratio of the both measurement results is equal to or greater than a predetermined determination threshold, the frequency band used by the mobile station in the uplink is the frequency band of the uplink used by the other cellular system. In a method of avoiding adjacent frequency interference in a cellular system, the frequency band is switched to separate, or the frequency band used by the mobile station in the downlink is switched to separate the frequency band from the frequency band of the downlink used by the other cellular system. The mobile station corrects the determination threshold by using the line connection information of the mobile station, and the adjacent frequency of the cellular system is reduced. Workaround. 4. A mobile station constituting one cellular system measures received power of a transmission signal transmitted from a base station of the other cellular system, and performs transmission transmitted from the base station of one cellular system. The received power of the signal is measured, both measurement results are notified to the base station controller of one cellular system, and in the base station controller, when the ratio of the both measurement results is equal to or greater than a predetermined determination threshold, the movement is performed. Switch the frequency band so that the station uses the frequency band used in the uplink from the frequency band used by the other cellular system in the uplink, or the frequency band used by the mobile station in the downlink is used by the other cellular system In the method for avoiding adjacent frequency interference in a cellular system, which switches the frequency band so that the frequency band is separated from the frequency band of the downlink channel, the mobile station is Notifying the base station control device in one cellular system of information about the reception power of the perch channel transmitted from the base station, the base station control device of the one cellular system, one notified from the mobile station The measurement result of the reception power of the transmission signal transmitted from the base station of the cellular system, using the information about the reception power of the perch channel transmitted from the base station of one cellular system notified from the mobile station A method for avoiding adjacent frequency interference in a cellular system, characterized by performing correction. 5. The adjacent frequency interference avoidance of the cellular system according to claim 4, wherein the base station control device of the one cellular system corrects the determination threshold value by using the line connection information of the mobile station. Method. 6. A mobile station constituting one cellular system measures received power of a transmission signal transmitted from a base station of the other cellular system, and performs transmission transmitted from the base station of one cellular system. The received power of the signal is measured, both measurement results are notified to the base station controller of one cellular system, and in the base station controller, when the ratio of the both measurement results is equal to or greater than a predetermined determination threshold, the movement is performed. Switch the frequency band so that the station uses the frequency band used in the uplink from the frequency band used by the other cellular system in the uplink, or the frequency band used by the mobile station in the downlink is used by the other cellular system In the adjacent frequency interference avoidance method of the cellular system that switches the frequency band to be separated from the frequency band of the downlink to be, the base station control device, the determination threshold Adjacent frequency interference avoiding method for cellular system and correcting with the line connection information of the mobile station. 7. A mobile station constituting one cellular system measures received power of a transmission signal transmitted from a base station of the other cellular system, and performs transmission transmitted from the base station of one cellular system. The received power of the signal is measured, and when the ratio of the both measurement results is equal to or greater than a predetermined determination threshold, the frequency band used by the mobile station in the uplink is the frequency band of the uplink used by the other cellular system. In a cellular system that switches the frequency band to separate, or in the cellular system that switches the frequency band to separate the frequency band used by the mobile station in the downlink from the frequency band of the downlink used by the other cellular system, the mobile station is The measurement result of the reception power of the transmission signal transmitted from the base station of one cellular system is displayed as the stop of the transmission power from the base station of one cellular system. Cellular system and correcting using information on the received power of the channel. 8. The cellular system according to claim 7, wherein the mobile station corrects the determination threshold value by using line connection information of the mobile station. 9. A mobile station constituting one cellular system measures received power of a transmission signal transmitted from a base station of the other cellular system, and performs transmission transmitted from the base station of one cellular system. The received power of the signal is measured, and when the ratio of the two measurement results is equal to or greater than a predetermined determination threshold, the frequency band used by the mobile station in the uplink is the frequency band of the uplink used by the other cellular system. In the cellular system that switches the frequency band so that the mobile station separates the frequency band, or the frequency band that the mobile station uses in the downlink to separate the frequency band from the frequency band of the downlink used by the other cellular system, the mobile station is The cellular system, wherein the determination threshold is corrected using the line connection information of the mobile station. 10. The mobile station constituting one cellular system measures the reception power of a transmission signal transmitted from the base station of the other cellular system, and the transmission power is transmitted from the base station of the one cellular system. The reception power of the transmission signal is measured, and both measurement results are notified to the base station controller of one cellular system, and in the base station controller, when the ratio of the both measurement results is equal to or more than the predetermined determination threshold value, Switching the frequency band used by the mobile station in the uplink to separate it from the uplink frequency band used by the other cellular system, or switching the frequency band used by the mobile station in the downlink to the other cellular system. In a cellular system that switches the frequency band so that it is separated from the frequency band of the downlink used by the system, the mobile station is a base station of one of the cellular systems. Notifying the base station controller in one cellular system of information about the received power of the perch channel to be transmitted, the base station controller of the one cellular system, the one cellular system notified from the mobile station. The cellular system is characterized in that the measurement result of the reception power of the transmission signal transmitted from the base station is corrected using information on the reception power of the perch channel notified from the mobile station. 11. The cellular system according to claim 10, wherein the base station control device of the one cellular system corrects the determination threshold value by using the line connection information of the mobile station. 12. The mobile station constituting one cellular system measures the reception power of a transmission signal transmitted from a base station of the other cellular system, and the transmission power is transmitted from the base station of one cellular system. The reception power of the transmission signal is measured, and both measurement results are notified to the base station control device of one cellular system, and in the base station control device, when the ratio of the both measurement results is equal to or more than the predetermined threshold value, , The frequency band used by the mobile station on the uplink is switched so as to be separated from the frequency band of the uplink used by the other cellular system, or the frequency band used by the mobile station on the downlink is In the cellular system, the frequency band is switched so as to be separated from the frequency band of the downlink used by the cellular system. Cellular systems, characterized in that the corrected using the line connection information of the mobile station to the determination threshold. 13. A means for measuring the received power of a downlink carrier used by a mobile station for connecting a line, and a downlink carrier used by the mobile station for connecting a line on a frequency axis. Means for measuring the reception power of the carrier of the adjacent downlink, means for measuring the information about the reception power of the perch channel transmitted from a plurality of base stations, and the downlink used by the mobile station in the connection of the line. Means for correcting the measurement result of the reception power of the carrier of the line by using the measurement result of the reception power of the perch channel transmitted from the plurality of base stations; and the correction result and the mobile station used for connection of the line Means for performing threshold determination using the downlink carrier and the measurement result of the received power of the downlink carrier adjacent on the frequency axis, and the line used by the mobile station based on the result of the threshold determination And a means for controlling the change of carrier of the mobile station. 14. A means for measuring the received power of a downlink carrier used by a mobile station for connecting a line, and a means for measuring the received power of a downlink carrier used by the mobile station for connecting a line on the frequency axis. Means for measuring the received power of the downlink carrier, the measurement results of the received power of the downlink carrier used by the mobile station for connecting the line, and the downlink carrier used by the mobile station for connecting the line And a means for performing a threshold value judgment using the measurement result of the received power of the downlink carrier adjacent on the frequency axis, a means for observing the line connection information of the mobile station, and a means used by the mobile station for line connection. Means for performing threshold value determination using the measurement result of the reception power of the downlink carrier and the measurement result of the reception power of the downlink carrier that is adjacent on the frequency axis, and the judgment used in the threshold value determination. A mobile station provided with means for correcting a constant threshold value using the line connection information, and means for performing change control of the carrier of the line used by the mobile station based on the threshold value judgment result. 15. A means for measuring the received power of a downlink carrier used by a mobile station for connection of a line, and a means for measuring the reception power of a downlink carrier used by the mobile station for connection of a line on the frequency axis. A means for measuring the received power of the downlink carrier, a means for measuring information about the received power of the perch channel transmitted from a plurality of base stations, and a downlink of the downlink used by the mobile station Means for correcting the measurement result of the received power of the carrier by using information about the received power of the perch channel transmitted from a plurality of base stations; and the downlink result used by the mobile station for connecting the line with the result of the correction. Means for performing threshold determination using the carrier and the measurement result of the reception power of the downlink carrier adjacent on the frequency axis, means for observing the line connection information of the mobile station, and the threshold A mobile station provided with means for correcting a judgment threshold value used in the judgment by using the line connection information and means for controlling the change of the carrier of the line used by the mobile station based on the result of the threshold value judgment. 16. A means for receiving a measurement result of received power of a downlink carrier used by a mobile station for connecting a line, and a downlink carrier and frequency used by the mobile station for connecting a line. Means for receiving the measurement result of the reception power of the downlink carrier adjacent on the axis, means for receiving the result of measuring the information on the reception power of the perch channel transmitted from a plurality of base stations, and the mobile station Means for correcting the measurement result of the reception power of the downlink carrier used in the connection of the line by using the information about the reception power of the perch channel transmitted from the plurality of base stations,
Correction result of the received power of the downlink carrier used by the mobile station for connection of the line and reception of the downlink carrier adjacent on the frequency axis to the downlink carrier used by the mobile station for connection of the line A base station control device comprising: a means for making a threshold judgment by using a measurement result of electric power; and means for making a change control of a carrier of a line used by a mobile station based on the result of the threshold judgment. 17. A means for receiving a measurement result of received power of a downlink carrier used by a mobile station for connecting a line, and a downlink carrier and a frequency axis used by the mobile station for connecting the line. In the means for receiving the measurement result of the reception power of the adjacent downlink carrier, the measurement result of the reception power of the downlink carrier used by the mobile station for connecting the line and the mobile station Means for performing a threshold determination using the downlink carrier used and the measurement result of the received power of the downlink carrier adjacent on the frequency axis,
Means for observing the line connection information of the mobile station, means for correcting the judgment threshold value used in the threshold value judgment using the line connection information, and a line used by the mobile station based on the threshold value judgment result. And a means for controlling the change of the carrier, the base station control device. 18. A means for receiving a measurement result of received power of a downlink carrier used by a mobile station for connecting a line, and a downlink carrier and a frequency axis used by the mobile station for connecting a line. In the means for receiving the measurement result of the reception power of the adjacent downlink carrier, a means for receiving the measurement result of the information about the reception power of the perch channel transmitted from a plurality of base stations, the mobile station Means for correcting the measurement result of the reception power of the downlink carrier used in the connection using the measurement result of the reception power of the perch channel transmitted from a plurality of base stations, the result of the correction and the movement Means for performing threshold value judgment using the downlink carrier used by the station for connecting the line and the measurement result of the received power of the downlink carrier adjacent on the frequency axis, and the line connection of the mobile station Means for observing information, means for correcting the threshold value used in the threshold value judgment using line connection information, and control for changing the carrier of the line used by the mobile station based on the result of the threshold value judgment. And a base station control device.