JPH10327456A - Channel frequency changeover method for mobile radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an electric field monitoring time for a channel frequency by conducting scanning at a high speed. SOLUTION: In a channel frequency check procedure (S1), a channel frequency used or detected within a radio zone of its own station is checked. In a channel frequency minimum interval calculation procedure (S2), a frequency interval between channel frequencies checked in the procedure (S1) is calculated and a minimum frequency interval is calculated from the frequency interval. In a procedure (S3) to discriminate a channel frequency distribution pattern, a pattern of the channel frequency distribution checked by the (S1) is discriminated. In a procedure (S4) to determine a channel frequency scanning method, the frequency scanning method is determined based on the minimum frequency interval calculated by the (S2) and the distribution pattern of the channel frequency discriminated by the discrimination procedure of the channel frequency distribution pattern. In a channel frequency scanning procedure (S5), scanning of the channel frequency is executed by the frequency scanning method determined by the (S4).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for switching a channel frequency of a mobile radio base station, and more particularly to a method of switching a channel frequency of a mobile radio base station used for monitoring an electric field in a mobile radio base station apparatus.

[0002]

2. Description of the Related Art Conventionally, in a mobile communication system, each mobile radio base station prepares all operable channels, and then determines the frequency of radio waves used in an adjacent radio zone and the usage frequency within its own zone. In order to prevent radio interference between frequencies, a method of monitoring the channel usage status in the surrounding base station and determining which channel to use in each base station communication at the base station, that is, DCA,
(Dynamic channel assignment
nt: dynamic channel assignment). To this end, each mobile radio base station uses a call transceiver or installs a dedicated electric field monitoring receiver and is used in an adjacent radio zone that comes into its own radio zone. Monitoring of the electric field level of radio waves has been performed. The radio wave used in the adjacent radio zone coming into the above-mentioned radio zone includes the radio wave of the "perch channel" described below.

Each mobile radio base station allocates a communication channel used when the mobile station communicates with another subscriber terminal to the mobile station in response to a request from the mobile station, and the mobile station allocates this communication channel. Therefore, each mobile radio base station constantly transmits a "perch channel", which is a channel used when communicating with the mobile radio base station. When the mobile station receives this "perch channel" which is constantly transmitted from each mobile radio base station, it measures the electric field level and the noise level of the frequency of this channel, and together with the "perch channel" frequency, the electric field level and the noise level The level is transmitted to the mobile radio base station transmitting the “perch channel”. Each mobile radio base station transmits information including the electric field level and the noise level of the frequency of the "perch channel" received from the mobile device to a higher-level supervisory control device that supervises and controls its own station. The higher-level supervisory control device that supervises and controls its own station uses the “perch channel” transmitted from each mobile radio base station in the radio zone adjacent to each other.
, Each mobile radio base station can be notified of the frequency transmitted from the mobile radio base station in the adjacent radio zone and used as the “perch channel” from the upper station, It is possible to monitor the electric field level of the frequency used for the "perch channel" transmitted from the mobile radio base station in the adjacent radio zone learned through the upper station.

Each mobile radio base station monitors all channels provided in its own radio zone in order to monitor radio interference caused by radio waves used in adjacent radio zones coming into its radio zone. Monitor the electric field level of The monitoring of the electric field levels of all the channels is such that, after the electric field monitoring of one channel is completed, the electric field monitoring of the next channel is performed. At this time, a method performed by a frequency synthesizer is used for switching the frequency in the electric field monitoring receiver of the mobile radio base station apparatus. The frequency switching by the frequency synthesizer is performed when a target channel is selected from the frequencies of several hundred channels based on the result of the electric field monitoring, and the frequency is switched to the selected channel frequency. As a technique related to a frequency switching method using a frequency synthesizer for shortening the channel switching time, a phase locked loop (phase locked loop) is used.
(op: PLL), a variable frequency divider is built in, the frequency division ratio is switched by frequency division ratio designation data, and the frequency of the output signal of the reference oscillator is frequency-divided into a frequency division ratio or a loop for use as a reference frequency. Japanese Patent Application Laid-Open Nos. Hei 7-336220 and Hei 7-2977 disclose a technique relating to a frequency synthesizer that switches a filter constant by dividing ratio designation data.
No. 12, etc.

FIG. 5 is a block diagram showing the configuration of a frequency synthesizer circuit for switching the channel frequency of a conventional mobile radio base station incorporating the above-mentioned variable frequency divider. The frequency synthesizer circuit shown in FIG. 5 is used in a communication transceiver or a dedicated electric field monitoring receiver.

The frequency synthesizer circuit for switching the channel frequency of the mobile radio base station shown in FIG. 5 has a reference having a frequency which is a reference frequency when controlling the channel frequency of the mobile radio base station to a desired frequency. A reference oscillator unit 1 for outputting a frequency signal 6; and a frequency divider for indicating a frequency division number “n”, which is data necessary to divide the frequency of the reference frequency signal 6 by n (positive integer). Number indication signal 7
And the reference oscillator unit 1 is calculated using the frequency division number “n”.
A frequency conversion unit 4 that divides the frequency of the reference frequency signal 6 output from by 1 / n and outputs it as a reference frequency signal 8 having a frequency that is 1 / n of the frequency of the reference frequency signal 6 A voltage-controlled oscillator 2 that changes the oscillation frequency in accordance with the control voltage and outputs a channel frequency signal 9, and reduces the channel frequency of the channel frequency signal 9 output from the voltage-controlled oscillator 2 to N (a positive integer). A frequency division number instruction signal 10 for instructing a frequency division number "N", which is data necessary for frequency division, is given, and a built-in frequency divider (not shown) uses this frequency division number "N". The channel frequency of the channel frequency signal 9 is divided by N, and the phase of the frequency of the reference frequency signal 8 output from the frequency converter 4 and the frequency of the channel frequency signal 9 output from the voltage controlled oscillator 2 are divided. A phase difference comparison unit 3 that compares a phase of a frequency divided by 1 / N with a divided frequency and outputs a control voltage 14 having a value corresponding to the detected phase difference to the voltage controlled oscillator 2; The channel frequency of the base station is switched in a predetermined order, and the frequency division number “n” is set to the frequency division number instruction signal 7 so that the frequency approaches the desired frequency sequentially.
And a control unit 5 which outputs the frequency division number “N” to the phase difference comparison unit 3 by the frequency division number instruction signal 10.

Next, the operation will be described.

In FIG. 5, a reference frequency signal 6 output from a reference oscillator 1 is input to a frequency converter 4.
The frequency of the reference frequency signal 6 input to the frequency conversion unit 4 is 1 / n in the frequency conversion unit 4 based on the frequency division number “n” indicated by the frequency division number instruction signal 7 output from the control unit 5. And output to the phase difference comparing section 3 as the reference frequency signal 8. Further, the channel frequency signal 9 output from the voltage controlled oscillator 2 is also input to the phase difference comparing unit 3. In addition, the control unit 5 outputs the frequency division number “N” for setting the frequency value of the channel frequency signal 9 output from the voltage controlled oscillator 2 to a desired frequency.
Is input to the phase difference comparing section 3. When the frequency division number “N” is input to the phase difference comparing section 3, the frequency of the channel frequency signal 9 output from the voltage controlled oscillator 2 is increased by the built-in frequency divider based on the input frequency division number “N”. To N
Divide by a factor of one. The phase difference comparing unit 3 calculates two frequencies of a divided frequency obtained by dividing the frequency of the channel frequency signal 9 by N and a frequency of the reference frequency signal 8 output from the frequency converting unit 4. The phases are compared by a built-in phase comparator, a voltage signal having a value proportional to the detected phase difference is obtained, a high-frequency component in the voltage signal is removed by a built-in filter, and the oscillation frequency of the voltage controlled oscillator 2 is changed. It is output to the voltage controlled oscillator 2 as a control voltage 14 to be controlled. The frequency of the channel frequency signal 9 output from the voltage controlled oscillator 2 by the control voltage 14 is
Changes to the oscillation frequency corresponding to. The frequency of the channel frequency signal 9 output from the voltage controlled oscillator 2 is further input to the phase difference comparison unit 3 and compared with the frequency of the reference frequency signal 8 output from the frequency conversion unit 4. Control voltage 14 converted from
Controls the oscillating frequency of the voltage-controlled oscillator 2 such that the input / output of the voltage-controlled oscillator 2 and the input / output of the phase difference comparator 3 form a loop, thereby forming a PLL loop. Therefore, by the operation of the PLL loop, the phase of the divided frequency of the frequency of the channel frequency signal 9 output from the voltage controlled oscillator 2 is synchronized with the phase of the frequency of the reference frequency signal 8 output from the frequency converter 4. become. That is, the channel frequency signal 9
In order to set the frequency division ratio corresponding to the desired channel frequency in the frequency divider incorporated in the phase difference comparison unit 3, the control unit 5
To output the second frequency-divided data to the phase difference comparing unit 3 as the frequency division number instruction signal 10, thereby allowing the voltage-controlled oscillator 2 to output the channel frequency signal 9 of the desired channel frequency. The frequency interval of the channel frequency of the channel frequency signal 9 output from 2 becomes equal to the reference frequency.

[0009]

In the above-described conventional method of switching the channel frequency of a mobile radio base station, when the electric field monitoring is performed using a telephone transceiver equipped with a frequency synthesizer circuit shown in FIG. Since the transmitter / receiver can operate the entire frequency range of the mobile communication system at a predetermined frequency interval, the reference frequency in the frequency synthesizer circuit was set to the frequency interval of the system channel frequency. The disadvantage is that it takes a considerable amount of time to scan all channel frequencies in order to monitor the electric field level of the channel.

In the case where a high-speed dedicated electric field monitoring receiver is provided to perform electric field monitoring, the number of communication transceivers to be installed is reduced correspondingly, and the operating channel frequency of the mobile radio base station apparatus is accordingly reduced. It has the disadvantage of becoming

An object of the present invention is to provide a method of switching a channel frequency of a mobile radio base station, which can perform high-speed scanning using a call transceiver and reduce the monitoring time of the electric field level of the channel frequency. It is in.

[0012]

A method for switching a channel frequency of a mobile radio base station according to the present invention is provided as a mobile station and a communication channel used by the mobile station for communication.
When monitoring the electric field level of a plurality of channel frequencies separated by a certain frequency interval predetermined in the operation of the mobile communication system, the frequency of the channel is sequentially switched by a frequency synthesizer to change the frequency of the channel. A mobile radio base station comprising a mobile radio base station that monitors the electric field level by performing a scan of the mobile station. A channel frequency investigation procedure for examining a channel frequency detected in the radio zone of (b), (B) a frequency interval between the channel frequencies examined in the channel frequency investigation procedure, and a channel frequency minimum for calculating a minimum frequency interval from the frequency interval Channels checked in the interval calculation procedure and (C) channel frequency investigation procedure A channel frequency distribution status pattern determination procedure for determining a wave number distribution pattern; and (D) a minimum frequency interval calculated in the channel frequency minimum interval calculation procedure and a channel frequency distribution determined in the channel frequency distribution status pattern determination procedure. A channel frequency scanning method determining procedure for determining the frequency scanning method from a pattern, and (E) performing a channel frequency scanning based on the frequency scanning method determined in the channel frequency scanning method determining procedure. Procedure.

Further, a method of switching a channel frequency of a mobile radio base station according to the present invention includes a frequency synthesizer, wherein the frequency synthesizer includes a reference oscillator for outputting a reference frequency, and a voltage for oscillating and outputting the output frequency of the frequency synthesizer. A control oscillator, a reference frequency output from the reference oscillator, and frequency conversion means for outputting a reference frequency that is a frequency obtained by dividing the reference frequency; and dividing the output frequency of the reference frequency and the output frequency of the frequency synthesizer. A phase difference comparing unit that compares a phase difference with the calculated frequency and outputs a control voltage that controls an output frequency of the voltage controlled oscillator; and a control unit that controls the phase difference comparing unit. In operation of a mobile communication system, the station is provided as a communication channel used for communication. When monitoring the electric field level of a plurality of channel frequencies separated by a predetermined frequency interval, the frequency synthesizer sequentially switches the frequency of the channel to scan the frequency of the channel, thereby monitoring the electric field. In a method for switching a channel frequency of a mobile radio base station comprising a mobile radio base station for monitoring a level, the control means includes: (A) a channel frequency used in a radio zone of the mobile station; A channel frequency investigation procedure for examining a channel frequency detected in the zone; (B) a frequency interval between the channel frequencies examined in the channel frequency investigation procedure; and a minimum channel frequency interval calculation for calculating a minimum frequency interval from the frequency interval. Procedure, (C) The distribution of the channel frequency examined in the channel frequency investigation procedure. (D) the minimum frequency interval calculated in the channel frequency minimum interval calculation procedure and the channel frequency distribution pattern determined in the channel frequency distribution status pattern determination procedure. Based on the frequency interval of the scan of the frequency, the minimum frequency to be the first frequency of the scan of the frequency, and determine the maximum frequency to be the last frequency of the scan of the frequency, the frequency interval and the minimum frequency A channel frequency scanning method determining step of determining all the frequencies to be scanned when scanning the frequency from the maximum frequency and determining a reference frequency generated by dividing the reference frequency based on the frequency interval, (E)
The step of performing the channel frequency scan is based on the reference frequency, the frequency interval, the minimum frequency of the frequency scan, and the maximum frequency of the frequency scan determined in the channel frequency scan method determination step. First frequency division data indicating a frequency division method when generating a frequency, and the phase difference comparing means inputting and dividing the frequency output from the voltage controlled oscillator, and dividing the frequency to obtain a phase difference with the reference frequency. Determining second frequency division data indicating how to divide the frequency output from the voltage controlled oscillator at the time of detection; outputting the first frequency division data to the frequency conversion means; Channel frequency scan execution procedure of outputting the frequency-divided data to the phase difference comparing means and performing a scan of the channel frequency. Ete constructed.

Further, a method for switching a channel frequency of a mobile radio base station according to the present invention comprises a frequency synthesizer, wherein the frequency synthesizer includes a reference oscillator for outputting a reference frequency, and a voltage for oscillating and outputting the output frequency of the frequency synthesizer. A control oscillator, a reference frequency output from the reference oscillator, and frequency conversion means for outputting a reference frequency that is a frequency obtained by dividing the reference frequency; and dividing the output frequency of the reference frequency and the output frequency of the frequency synthesizer. A phase difference comparing unit that compares a phase difference with the calculated frequency and outputs a control voltage that controls an output frequency of the voltage controlled oscillator; and a control unit that controls the phase difference comparing unit. In operation of a mobile communication system, the station is provided as a communication channel used for communication. When monitoring the electric field level of a plurality of channel frequencies separated by a predetermined frequency interval, the frequency synthesizer sequentially switches the frequency of the channel to scan the frequency of the channel, thereby monitoring the electric field. In a method for switching a channel frequency of a mobile radio base station comprising a mobile radio base station for monitoring a level, the control means includes: (A) a channel frequency used in a radio zone of the mobile station; A channel frequency investigation procedure for examining a channel frequency detected in the zone; (B) a frequency interval between the channel frequencies examined in the channel frequency investigation procedure; and a minimum channel frequency interval calculation for calculating a minimum frequency interval from the frequency interval. Procedure, (C) The distribution of the channel frequency examined in the channel frequency investigation procedure. (D) the channel frequency scanning method determining step is to determine the minimum frequency interval calculated in the channel frequency minimum interval calculating step and the channel frequency distribution status pattern determining step. Based on the distribution pattern of the channel frequencies, the minimum frequency that is the first frequency of the frequency scan, the minimum frequency that is the first frequency of the frequency scan, and the maximum frequency that is the last frequency of the frequency scan Determine a frequency, and divide the channel frequencies to be scanned, including the minimum frequency and the maximum frequency, into a plurality of groups, and as a channel frequency of the first group, a constant from a low channel frequency to a high channel frequency. Channels to be scanned at intervals of frequency And a frequency shifted as a channel frequency of the second group by a frequency higher than the channel frequency of the first group by the minimum frequency interval calculated by the channel frequency minimum interval calculation procedure. Selecting a channel frequency, and selecting a channel frequency whose frequency is shifted to a higher frequency by the minimum frequency interval than the channel frequency of the second group also as the channel frequency of the third group. After selecting the channel frequencies to be scanned in the group of the groups, the distribution of the channel frequencies determined in the channel frequency distribution situation pattern determination procedure is compared with the channel frequencies in each group, and the channels to be scanned are selected. Any of the frequencies selected as frequencies are When a group that does not exist in the distribution of channel frequencies determined in the number distribution situation pattern determination procedure is among the plurality of groups, the frequencies of the group are excluded from the channel frequencies to be scanned. A channel frequency scanning method determining step of determining all frequencies to be scanned when scanning the frequency, and determining a reference frequency to be generated by dividing the reference frequency based on the fixed frequency interval; (E) The channel frequency scan performing procedure is determined in the channel frequency scan method determining procedure,
A first frequency indicating a frequency dividing method when generating the reference frequency based on the reference frequency, the fixed frequency interval, a minimum frequency of scanning of the frequency in each group, and a maximum frequency of the frequency. The divided data and the frequency difference output from the voltage controlled oscillator when the phase difference comparing means inputs and divides the frequency output from the voltage controlled oscillator to detect the phase difference with the reference frequency. Determining second frequency-divided data indicating a manner of frequency division, outputting the first frequency-divided data to the frequency conversion means, outputting the second frequency-divided data to the phase difference comparing means, A channel frequency scan execution procedure for executing a scan of the channel frequency.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart showing an embodiment of a method for switching a channel frequency of a mobile radio base station according to the present invention.

The method of switching the channel frequency of the mobile radio base station according to the present invention shown in FIG. 1 is used for scanning the channel frequency when monitoring the electric field in the radio zone of the mobile station, and the frequency synthesizer circuit shown in FIG. Can be operated and executed.

The method of switching the channel frequency of the mobile radio base station according to the present invention shown in FIG. 1 uses a channel for examining the channel frequency used in its own radio zone and the channel frequency detected in its own radio zone. A frequency checking procedure (S1: step 1 in FIG. 1), a frequency interval between the channel frequencies checked in the channel frequency checking procedure, and a minimum channel frequency calculating procedure for calculating a minimum frequency interval from the frequency interval (step 2) A channel frequency distribution situation pattern determining procedure for determining a channel frequency distribution pattern examined in the channel frequency survey procedure (step 3); a minimum frequency interval and a channel frequency distribution situation pattern calculated in the channel frequency minimum interval calculating procedure; The frequency scanning method is determined based on the channel frequency distribution determined in the determination procedure. And a channel frequency scan execution procedure (step 5) for executing a channel frequency scan based on the frequency scan method determined in the channel frequency scan method determination procedure. You.

Next, the operation will be described.

In the electric field monitoring operation state, the control unit 5 shown in FIG. 5 uses the mobile radio base station in its own radio zone to check what channel frequency is being used by the channel frequency investigation procedure. The frequencies of all communication channels between the mobile station and the mobile station are investigated. For this purpose, the control unit 5
When the mobile station communicates with another subscriber, the mobile station checks the channel frequency included in the information on the "perch channel" transmitted to the mobile radio base station, that is, the frequency of the communication channel. Further, the control unit 5 monitors the electric field levels of all the channels in its own radio zone in order to monitor the radio wave interference by the radio waves of the adjacent radio zone coming into its own radio zone by the channel frequency investigation procedure. The mobile station searches for information from the electric field monitoring receiver in its own mobile radio base station and checks the channel frequency detected in its own radio zone (step 1). Next, the control unit 5
According to the channel frequency minimum interval calculation procedure, the state of the distribution of the spectrum of the channel frequency investigated in step 1 is examined, and the minimum interval of the used channel frequency is determined (step 2). Further, the control unit 5 determines the pattern of the distribution status of the spectrum of the channel frequency in the own station wireless zone checked by the channel frequency investigation procedure by the channel frequency distribution status pattern determination procedure (step 3). Next, the control unit 5 determines the minimum frequency interval calculated in the channel frequency minimum interval calculation procedure in step 2 and the channel frequency determined in the channel frequency distribution status pattern determination procedure in step 3 by the channel frequency scan method determination procedure. A channel frequency scanning method is determined based on the distribution situation pattern (step 4).
Finally, the control unit 5 performs the channel frequency scan procedure based on the channel frequency scan method searched in step 4 based on the frequency division number “n” (first frequency division data).
To the frequency conversion unit 4 to instruct the frequency division ratio to set the reference frequency, and to sequentially transmit the frequency division number “N” (second frequency division data) to the phase difference comparison unit 3 for scanning. The dividing ratio corresponding to the desired channel frequency is determined by the phase difference comparing unit 3.
Then, the channel frequency is scanned according to the channel frequency scanning method determined in step 3 (step 5).

Next, the operation of the present invention will be described with reference to an embodiment showing specific channel frequencies.

FIG. 2 shows a reference frequency (kHz), a reference frequency (kHz), and a frequency of the reference frequency signal 6 of the frequency synthesizer circuit shown in FIG. Number of channels (CH) and frequency division number "N" that can be set in the transceiver for communication
And the value of the frequency division number “n” are shown. As shown in the channel frequency setting column, a case of setting a channel frequency during a call (prior art), a case of setting a channel frequency during electric field monitoring according to the present invention (reference frequency is 100 kHz), and a case of monitoring an electric field according to the present invention Setting of the channel frequency (reference frequency is 400 kHz)
Reference frequency (kHz), reference frequency (kHz
z), the number of channels (CH), the division number “N”, and the division number “n” are shown.

When setting the channel frequency during a call,
Although the reference frequency is 25 kHz, when monitoring the electric field, the intervals between the channel frequencies to be scanned and the distribution state of the channel frequencies are determined by the procedures shown in Steps 1 to 3 so that Steps 4 and 5 are performed. In the detailed operation of the above, various scanning methods are performed. As an example, here, the case of setting the channel frequency (reference frequency is 100 kHz) during the electric field monitoring shown in FIG. Setting of channel frequency (reference frequency is 400k
(Hz).

Here, the radio frequency band in the radio zone of the mobile radio base station is 940 MHz to 960 MHz.
, And a channel frequency (for 800 CHs) is arranged within the band at a predetermined frequency interval (25 kHz interval) predetermined for operation of the mobile communication system. Shall be

First, the case where the channel frequency is set at the time of electric field monitoring shown in FIG. 2 (the reference frequency is 100 kHz) will be described.

If the channel frequency is set at the time of electric field monitoring (the reference frequency is 100 kHz), step 2
And the minimum interval of the channel frequency to be monitored is 100k
In step 3, the description will be made on the assumption that the pattern of the distribution state of the channel frequency has been found to be a distribution without any bias over the entire band.
Therefore, in step 4, the control unit 5 of FIG.
The minimum frequency interval (100 kHz) calculated in the channel frequency minimum interval calculation procedure and the distribution pattern of the channel frequency determined in the channel frequency distribution status pattern determination procedure in step 3 are distributions without any bias over the entire band. Based on this, the frequency interval of the frequency scan (100 kHz), the minimum frequency (940 MHz) which is the first frequency of the frequency scan, and the maximum frequency (960 Mhz) which is the last frequency of the frequency scan
Hz). Further, the control unit 5 determines all the channel frequencies to be scanned at the time of scanning the channel frequency from the frequency interval, the minimum frequency, and the maximum frequency, and based on the frequency interval, the frequency conversion unit 4 Reference frequency (100 kHz) that is generated by dividing the reference frequency (400 kHz) of unit 1 and output
To determine.

In step 5, the control unit 5 shown in FIG. 5 executes the channel frequency scan procedure, and based on the channel frequency scan method determined in step 4 by the channel frequency scan method determination procedure, determines the frequency division number. "4" is sent to the frequency conversion unit 4 as "n", and the frequency division ratio is instructed to set the reference frequency, and the frequency division number "N" for setting the minimum frequency (940 MHz) of the channel frequency. Is transmitted to the phase difference comparing section 3 and the next channel frequency (940.1 M
Hz) is set to “940” as the frequency division number “N”.
1 "is transmitted to the phase difference comparing section 3, and the frequency division ratio corresponding to the scan frequency is sequentially instructed to the phase difference comparing section 3, whereby the channel frequency is determined in accordance with the channel frequency scanning method determined in step 3. To scan.

That is, a frequency division number indicating how to divide the reference frequency when generating the reference frequency based on the reference frequency, the frequency interval of the channel frequency, the minimum frequency of the channel frequency scan, and the maximum frequency of the channel frequency scan. “N”, the phase difference comparison unit 3 receives the frequency output from the voltage controlled oscillator unit 2 and divides the frequency to detect the phase difference from the reference frequency. A frequency division number “N” indicating a frequency division method is determined, and the frequency division number “n” is determined by the frequency conversion unit 4.
And outputs the frequency division number “N” to the phase difference comparison unit 3 to execute scanning of the channel frequency.

As described above, since the minimum interval between the channel frequencies to be monitored is 100 kHz, the reference frequency is set to 100 kHz. Also, the value of the frequency division number “n” is 100 kHz which is four times 25 kHz, which is four times 25 kHz, as “4” which is a quarter of “16” in the case of setting the channel frequency during a call. . The lowest channel frequency to scan is 940MHz
Since the reference frequency is 100 kHz, the value of the frequency division number “N” is “9400”. Since the highest channel frequency to be scanned is 960 MHz, the number of channels is included in the radio frequency band of 940 MHz to 960 MHz for 200 CHs. , 940 MHz to 960 MHz are determined to be uniformly distributed in the radio frequency band. Therefore, it is necessary to perform electric field monitoring at all channel frequencies in the 940 MHz to 960 MHz radio frequency band, and it is necessary to perform scanning. The number of certain channels is 200CH. FIG. 3 shows a method of scanning the channel frequency at this time. Scanning is performed at an interval of 100 kHz from a channel frequency 11 of 940 MHz to a channel frequency 12 of 960 MHz. As described above, scanning of the channel frequency during electric field monitoring is performed at a frequency interval of 25 kHz, which is a frequency interval during a normal call.
By using the minimum frequency interval of 100 kHz calculated by checking the presence or absence of a channel frequency in the wireless zone in Steps 1 to 3 without using z, scanning is performed four times faster than in the conventional case. Can be.

Next, a description will be given of a case where the channel frequency is set (reference frequency is 400 kHz) during electric field monitoring shown in FIG.

In this case, the presence or absence of a channel frequency in the wireless zone is determined as shown in FIG. 4A as a result of checking the presence or absence of a channel frequency in the wireless zone in step 1. .

In FIG. 4A, a channel frequency 21 of 940 MHz, a channel frequency 24 having a frequency 100 kHz higher than the channel frequency 21, a channel frequency 27 having a frequency 200 kHz higher than the channel frequency 24, and a channel frequency having a frequency 100 kHz higher than the channel frequency 27 are shown. 22, the channel frequency 25 which is 100 kHz higher than the channel frequency 22;
A channel frequency 28 which is higher than 00 kHz, followed by a channel frequency 23, 1
It can be seen that the channel frequency is skipped everywhere, such as a channel frequency 26 having a frequency higher by 00 kHz and a channel frequency 29 having a frequency of 960 MHz higher than the channel frequency 26 by 200 kHz. In step 2, the minimum interval of the channel frequency is calculated as 100 kHz. Further, in step 3, as shown in FIG. 4A, the portion where the channel frequency is missing is between the channel frequency 24 and the channel frequency 27 and the channel frequency 2
5 and the channel frequency 28, and between the channel frequency 26 and the channel frequency 29, and if the arrangement of the channel frequencies in the part omitted in the drawing is the same, every 400 kHz It turns out that the channel frequency is missing.

When such channel frequency distribution is determined in step 3, the scanning method determining procedure in step 4 operates according to the following detailed procedure.

In the channel frequency scanning method determining procedure of step 4, the control unit 5 determines the first frequency of the channel frequency scanning based on the channel frequency distribution pattern determined in the channel frequency distribution status pattern determining procedure of step 3. Is determined, and the maximum frequency that is the last frequency of the channel frequency scan is determined. Next, the channel frequencies to be scanned including the minimum frequency and the maximum frequency are divided into a plurality of groups, and a fixed frequency interval of 400 kHz from a low channel frequency to a high channel frequency as a first group of channel frequencies. Use to select the channel frequency to be scanned at intervals. Further, as the channel frequency of the second group, the frequency is higher by 100 kHz than the channel frequency of the first group based on the data of the minimum frequency interval of 100 kHz calculated in the channel frequency minimum interval calculation procedure of step 2. All of the channel frequencies shifted are selected, and the channel frequencies of the third group are similarly selected as the channel frequencies whose frequencies are shifted by 100 kHz higher than the channel frequencies of the second group. Select a channel frequency to scan the group. Thereafter, the distribution of the channel frequencies determined in the channel frequency distribution status pattern determination procedure of step 3 is compared with the channel frequencies in each group. As a result of this collation, there was a group among a plurality of groups in which none of the frequencies selected as channel frequencies to be scanned existed in the distribution of the channel frequencies determined in the channel frequency distribution situation pattern determination procedure. when,
The frequencies of this group are excluded from the channel frequencies to be scanned, and all the frequencies to be scanned at the time of the frequency scanning are determined. As described above, the interval between the missing channel frequencies is 400 kHz. Is determined to be 400 kHz.

Further, according to the channel frequency scan execution procedure in step 5, the control unit 5 scans the reference frequency, the minimum channel frequency interval, and the frequency in each group determined in the channel frequency scan method determination procedure in step 4. Based on the minimum frequency and the maximum frequency, a frequency division number “n” indicating a frequency division method for generating a reference frequency is determined.
Send to Further, the controller 5 controls the voltage difference when the phase difference comparator 3 receives the channel frequency output from the voltage controlled oscillator 2 and divides the channel frequency to detect a phase difference from the reference frequency. The frequency division number “N” indicating how to divide the frequency output from the oscillator unit 2 is determined, and is output to the phase difference comparison unit 3 to execute a scan of the channel frequency. That is, in the scan method determination procedure of step 4, the channel frequency 21 and the channel frequency 2
2. A scan sequence at 400 kHz intervals at channel frequency 23, a scan sequence at 400 kHz intervals at channel frequencies 24, 26 and 26, and a scan sequence at 400 kHz intervals at channel frequencies 27, 28 and 29 It is determined that scanning is performed in three series. In this case, the scanning method is as follows. After the first scan sequence is scanned, the scan frequency is returned to the original value,
The scanning is performed from the channel frequency 24 which is higher by kHz, and the scanning is further performed from the channel frequency 27 by returning to the channel frequency 27. In step 5, in order to set the reference frequency to 100 kHz, the value of the frequency division number “n” is set to “1”, which is 1/16 of “16” in the case of setting the channel frequency during communication. Is set to 400 kHz, which is four times 25 kHz. In this case, the lowest channel frequency to scan is 940M
Hz, and the reference frequency is 400 kHz, the value of the frequency division number “N” corresponding to the lowest channel frequency 21 in FIG. 4A is “2350”.

As described above, when the distribution status of the channel frequency is examined, if the channel frequency to be monitored is skipped at regular intervals, the remaining channel frequency sequence is removed except for the missing channel frequency sequence. By dividing all the channel frequencies to be monitored into a plurality of groups and performing scanning as described above, it is not necessary to scan a sequence of missing channel frequencies, and the time can be reduced accordingly. In FIG. 2, the number of channels in the case of setting the channel frequency at the time of electric field monitoring (the reference frequency is 400 kHz) is 150CH, but the number of channels to be scanned per one of the three scans is 50 channels, which indicates the number of channels for the three scans.

The case where the channel frequency is set (reference frequency is 400 kHz) during the electric field monitoring shown in FIG. 2 has been described above with reference to FIG. 4 (a). , Three scans are sequentially processed, so that three scans of 150 CHs are performed as a monitoring target channel, and three scans of 150 CHs are required. However, if three scans take three
If we were to do it in parallel with the circuit's frequency synthesizer circuit,
The scan time of 50 channels is enough, and the scan time can be reduced to one third. FIG. 4B shows a case where three scans are performed in parallel by three frequency synthesizer circuits. Scanning by the first frequency synthesizer circuit is performed like channel frequencies 41, 42, and 43, respectively.
Scanning by the second frequency synthesizer circuit is performed like channel frequencies 51, 52, and 53, and
The scan by the frequency synthesizer circuit is performed like channel frequencies 61, 62 and 63.

[0038]

As described above, the method of switching the channel frequency of the mobile radio base station according to the present invention monitors the electric field of the channel frequency in the zone using the telephone transceiver equipped with the frequency synthesizer circuit. Sometimes, in the frequency synthesizer circuit, a channel frequency investigation procedure for examining the channel frequency used in the radio zone of the own station and the channel frequency detected in the radio zone of the own station,
The frequency intervals between the channel frequencies examined in the channel frequency investigation procedure, the minimum frequency interval calculation procedure for calculating the minimum frequency interval from the frequency intervals, and the distribution pattern of the channel frequencies examined in the channel frequency investigation procedure are determined. Channel frequency distribution situation pattern determining procedure to be performed, and the frequency scanning method based on the minimum frequency interval calculated in the channel frequency minimum interval calculating procedure and the channel frequency distribution situation pattern determined in the channel frequency distribution situation pattern determining procedure. A channel frequency scan method determining step of determining the channel frequency scan method for performing the scan of the channel frequency based on the frequency scan method determined in the channel frequency scan method determining step, and The presence or absence of the electric field of the channel frequency is calculated, the minimum interval time of the channel frequency is calculated, the distribution state of the channel frequency can be determined, and the scanning method of the channel frequency adapted to the distribution state of the channel frequency can be determined. Therefore, it is possible to perform high-speed scanning, and it is possible to shorten the monitoring time of the electric field level of the channel frequency to be scanned.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of a method for switching a channel frequency of a mobile radio base station according to the present invention.

FIG. 2 is an explanatory diagram showing a method of setting a channel frequency by a method of switching a channel frequency of the mobile radio base station shown in FIG.

FIG. 3 is an explanatory diagram showing a method of scanning a channel frequency when setting a channel frequency (a reference frequency is 100 kHz) during electric field monitoring.

FIG. 4 is an explanatory diagram showing a method of scanning a channel frequency when the channel frequency is set (reference frequency is 400 kHz) during electric field monitoring.

FIG. 5 is a block diagram showing a configuration of a frequency synthesizer circuit for switching a channel frequency of a mobile radio base station.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reference oscillator part 2 Voltage control oscillator part 3 Phase difference comparison part 4 Frequency conversion part 5 Control part

Claims (3)

[Claims] 1. A mobile station, and a plurality of channels provided as communication channels used for communication by the mobile station and spaced apart from each other at a predetermined frequency interval predetermined in operation of a mobile communication system. When monitoring the electric field level of the frequency, a mobile radio base station including a mobile radio base station that monitors the electric field level by scanning the frequency of the channel by sequentially switching the frequency of the channel by a frequency synthesizer In the frequency switching method, (A) a channel frequency investigation procedure for examining a channel frequency used in the radio zone of the own station and a channel frequency detected in the radio zone of the own station, and (B) a channel frequency investigation procedure Calculate the frequency interval between the examined channel frequencies and the minimum frequency interval from the frequency interval. (C) a channel frequency distribution status pattern determination procedure for determining a channel frequency distribution pattern checked in the channel frequency investigation procedure, and (D) a minimum calculated in the channel frequency minimum interval calculation procedure. A channel frequency scanning method determining procedure for determining the frequency scanning method from the frequency interval and the channel frequency distribution pattern determined in the channel frequency distribution situation pattern determining procedure,
(E) performing a channel frequency scan based on the frequency scan method determined in the channel frequency scan method determination procedure. Switching method. 2. A frequency synthesizer, the frequency synthesizer comprising: a reference oscillator for outputting a reference frequency;
A voltage controlled oscillator that oscillates and outputs an output frequency of the frequency synthesizer; a frequency conversion unit that receives a reference frequency output from the reference oscillator and outputs a reference frequency that is a frequency obtained by dividing the reference frequency; Phase difference comparing means for comparing a phase difference between a frequency and a frequency obtained by dividing the output frequency of the frequency synthesizer, and outputting a control voltage for controlling the output frequency of the voltage controlled oscillator; and control for controlling the phase difference comparing means. Means, a mobile station, provided as a communication channel used for communication by the mobile station, a plurality of channel frequencies spaced apart at predetermined frequency intervals in the operation of the mobile communication system When monitoring the electric field level, the frequency synthesizer sequentially cuts the frequency of the channel. And a mobile radio base station that monitors the electric field level by scanning the frequency of the channel. In the method of switching the channel frequency of the mobile radio base station, the control unit includes: Channel frequency investigation procedure for examining the channel frequency used in the mobile station and the channel frequency detected in the radio zone of the own station, (B) the frequency interval between the channel frequencies examined in the channel frequency investigation procedure, and the frequency interval (C) a channel frequency distribution situation pattern determining procedure for determining a channel frequency distribution pattern checked in the channel frequency checking procedure, and (D) the channel frequency minimum spacing. The minimum frequency interval calculated in the calculation procedure and the channel frequency distribution status pattern Based on the channel frequency distribution pattern determined in the determination procedure, the frequency interval of the frequency scan, the minimum frequency that is the first frequency of the frequency scan, and the maximum frequency that is the last frequency of the frequency scan Is determined, and all frequencies to be scanned at the time of scanning the frequency are determined from the frequency interval, the minimum frequency, and the maximum frequency, and the reference frequency is divided and generated based on the frequency interval. A channel frequency scanning method determining procedure for determining a reference frequency to be performed, and (E) the channel frequency scanning performing procedure includes the minimum of the reference frequency, the frequency interval, and the frequency scanning determined in the channel frequency scanning method determining procedure. Frequency and the maximum frequency of the scan of said frequency A first frequency division data indicating a frequency division method when the reference frequency is generated, and a frequency output from the voltage controlled oscillator by the phase difference comparing means, dividing the frequency by dividing the frequency with the reference frequency. Determining second frequency-divided data indicating how to divide the frequency output from the voltage-controlled oscillator when detecting a phase difference, and outputting the first frequency-divided data to the frequency conversion means; A channel frequency scanning method for outputting the second frequency-divided data to the phase difference comparing means and performing a scan of the channel frequency. 3. A frequency synthesizer, comprising: a reference oscillator for outputting a reference frequency;
A voltage controlled oscillator that oscillates and outputs an output frequency of the frequency synthesizer; a frequency conversion unit that receives a reference frequency output from the reference oscillator and outputs a reference frequency that is a frequency obtained by dividing the reference frequency; Phase difference comparing means for comparing a phase difference between a frequency and a frequency obtained by dividing the output frequency of the frequency synthesizer, and outputting a control voltage for controlling the output frequency of the voltage controlled oscillator; and control for controlling the phase difference comparing means. Means, a mobile station, provided as a communication channel used for communication by the mobile station, a plurality of channel frequencies spaced apart at predetermined frequency intervals in the operation of the mobile communication system When monitoring the electric field level, the frequency synthesizer sequentially cuts the frequency of the channel. And a mobile radio base station that monitors the electric field level by scanning the frequency of the channel. In the method of switching the channel frequency of the mobile radio base station, the control unit includes: Channel frequency investigation procedure for examining the channel frequency used in the mobile station and the channel frequency detected in the radio zone of the own station, (B) the frequency interval between the channel frequencies examined in the channel frequency investigation procedure, and the frequency interval Channel frequency minimum interval calculating procedure for calculating the minimum frequency interval from (C), a channel frequency distribution situation pattern determining procedure for determining a channel frequency distribution pattern checked in the channel frequency investigating procedure, (D) the channel frequency scanning method The determining step is the minimum cycle calculated in the channel frequency minimum interval calculating step. Based on several intervals and the channel frequency distribution pattern determined in the channel frequency distribution situation pattern determination procedure, the minimum frequency that is the first frequency of the frequency scan and the minimum frequency that is the first frequency of the frequency scan And a maximum frequency that is the last frequency of the frequency scan is determined, and the channel frequencies to be scanned including the minimum frequency and the maximum frequency are divided into a plurality of groups, and a channel of a first group is determined. From the low channel frequency as a frequency to a high channel frequency, a channel frequency to be scanned is selected at intervals of a predetermined frequency interval, and a frequency is set as a channel frequency of the second group from the channel frequency of the first group. The channel frequency minimum interval calculated by the procedure A channel frequency shifted to a higher frequency by the minimum frequency interval is selected, and the channel frequency of the third group is higher than the channel frequency of the second group by the minimum frequency interval. After selecting the channel frequencies to be scanned for all groups, such as selecting the shifted channel frequencies, the distribution of the channel frequencies determined in the channel frequency distribution situation pattern determination procedure and the channel frequencies in each group The group in which none of the frequencies selected as the channel frequencies to be scanned are present in the channel frequency distribution determined in the channel frequency distribution situation pattern determination procedure is included in the plurality of groups. The frequency of the group is scanned A channel that excludes from the target channel frequency, determines all frequencies to be scanned when scanning the frequency, and determines a reference frequency to be generated by dividing the reference frequency based on the fixed frequency interval. Frequency scan method determination procedure, (E)
The channel frequency scan implementation procedure, determined in the channel frequency scan method determination procedure, the reference frequency, the constant frequency interval, the minimum frequency of the scan of the frequency in each group, and the maximum frequency of the frequency. The first frequency division data indicating a frequency division method when the reference frequency is generated and the frequency output from the voltage controlled oscillator are input by the phase difference comparing means to divide the reference frequency. And second frequency-divided data indicating how to divide the frequency output from the voltage-controlled oscillator when detecting the phase difference between the first frequency-divided data and the first frequency-divided data. And outputting the second frequency-divided data to the phase difference comparing means to execute a scan of the channel frequency. Implementation procedure, a method of switching the channel frequency of the mobile radio base station, comprising the.