JP3647837B2 - Frequency selection method in mobile station, mobile station, and frequency selection program - Google Patents

Frequency selection method in mobile station, mobile station, and frequency selection program Download PDF

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Publication number
JP3647837B2
JP3647837B2 JP2002313052A JP2002313052A JP3647837B2 JP 3647837 B2 JP3647837 B2 JP 3647837B2 JP 2002313052 A JP2002313052 A JP 2002313052A JP 2002313052 A JP2002313052 A JP 2002313052A JP 3647837 B2 JP3647837 B2 JP 3647837B2
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Prior art keywords
frequency
mobile station
quality
frequencies
communication
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JP2004153311A (en
Inventor
雄啓 井田
暢一 宇野
充生 岩永
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株式会社エヌ・ティ・ティ・ドコモ
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a frequency selection method for selecting a frequency that a mobile station should use for communication in a mobile communication system having a mobile station and a base station.
[0002]
[Prior art]
Conventionally, in a mobile communication system, a mobile station searches for a plurality of frequencies that may be used for communication, selects a frequency having the best quality from among them as a frequency to be used for communication, and enters a standby state. In a mobile communication system in which an operation is performed in which a base station transmits signals of a plurality of frequencies with the same power, when the mobile station measures the quality of the plurality of frequencies, the base station on the transmission side and the reception side Depending on the frequency characteristics of an antenna of a certain mobile station, time reasons, location reasons, measurement errors, etc., it may be determined that the quality of a specific frequency is better than other frequencies. For this reason, when the mobile station selects a frequency with the best quality, the selected frequency is biased.
[0003]
In addition, in IMT-2000 (International Mobile Telecommunicaitons 2000), which is a third generation mobile communication system, there are about 300 frequencies that can be used by mobile stations. For this reason, if the mobile station searches for all frequencies, it takes time to select a frequency and enter a standby state, and the battery consumption also increases. As a countermeasure for such a problem, the mobile station preferentially searches for a frequency used in the past (see Non-Patent Document 1), and selects a frequency used for communication from the searched frequencies. There is. However, in this method, no consideration is given to avoid occurrence of bias when the mobile station selects a frequency.
[0004]
[Non-Patent Document 1]
“3GPP TS 25.304 V3.10.0 (2002-03)”, 5.2.3 Cell Selection Process b) StoredInformation Cell Selection
[0005]
[Problems to be solved by the invention]
As described above, the fact that the frequency selected by the mobile station is biased does not necessarily mean that the mobile station selects the frequency as evenly as possible to improve the utilization efficiency of radio resources in the entire mobile communication system. It is not an appropriate selection method.
[0006]
The present invention solves the above-described problems, and an object of the present invention is to provide a frequency selection method capable of selecting a frequency used by a mobile station for communication as evenly as possible.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a frequency selection method for selecting a frequency to be used by a mobile station for communication in a mobile communication system, as described in claim 1. Measure the quality of the frequency that may be used for the frequency, and the difference between the best quality frequency from the measured frequency and the best quality frequency is , Eliminate the bias of the selected frequency A frequency within a predetermined range is specified as a selection candidate, and a frequency to be used for communication by the mobile station is randomly selected from the specified frequencies.
[0008]
In such a frequency selection method, the mobile station uses a frequency having the best quality and a frequency whose quality difference is within a predetermined range as a selection candidate. Less. For this reason, while not making all the frequencies that may be used for communication as selection candidates, as many frequencies as possible can be made selection candidates. Furthermore, the mobile station randomly selects a frequency to be used for communication by the mobile station from among the selection candidate frequencies, and can select the frequencies as evenly as possible.
[0009]
Further, as described in claim 2, the present invention is a frequency selection method for selecting a frequency to be used for communication by a mobile station in a mobile communication system, and the possibility of being used for communication of the mobile station. The frequency of a certain frequency is measured, a frequency of a predetermined quality or higher is specified as a selection candidate from the measured frequencies, and a frequency to be used for communication by the mobile station is randomly selected from the specified frequencies. It is characterized by that.
[0010]
In such a frequency selection method, the mobile station uses a frequency of a predetermined quality or higher as a selection candidate, and minimizes the conditions for selection candidates as much as possible. For this reason, as in the first aspect of the present invention, not all frequencies that may be used for communication are selected as candidates, but as many frequencies as possible can be selected. Furthermore, the mobile station randomly selects a frequency to be used for communication by the mobile station from among the selection candidate frequencies, and can select the frequencies as evenly as possible.
[0011]
Further, the present invention provides a possibility of being used for communication of the mobile station in a frequency selection method for selecting a frequency to be used by a mobile station for communication in a mobile communication system. The quality of a certain frequency is measured, and is equal to or higher than a predetermined quality among the measured frequencies, and the difference between the best quality frequency and the best quality frequency is , Eliminate the bias of the selected frequency A frequency within a predetermined range is specified as a selection candidate, and a frequency to be used by the mobile station for communication is selected at random from the specified frequencies.
[0012]
In such a frequency selection method, the mobile station uses a frequency that is equal to or higher than a predetermined quality and that has a frequency difference between the best quality frequency and the best quality frequency within a predetermined range as a selection candidate, The number of selection candidates is minimized. For this reason, as in the inventions described in claims 1 and 2, not all frequencies that may be used for communication are selected candidates, but as many frequencies as possible can be selected candidates. Furthermore, the mobile station randomly selects a frequency to be used for communication by the mobile station from among the selection candidate frequencies, and can select the frequencies as evenly as possible.
[0013]
Further, according to the present invention, as described in claim 4, in the frequency selection method in the mobile station according to claim 2 or 3, the predetermined quality is a reference value that does not require frequency change. Features.
[0014]
In this case, since the mobile station selects a frequency having a quality equal to or higher than a reference value that does not need to be changed, an appropriate frequency can be selected, and the frequency is frequently changed. Can be prevented from being loaded.
[0015]
According to a fifth aspect of the present invention, in the frequency selection method for selecting a frequency to be used for communication by the mobile station in the mobile communication system, the frequency used by the mobile station in the past is stored. Then, under a predetermined condition, a frequency other than the stored frequency is selected as a frequency that the mobile station should use for communication.
[0016]
In such a frequency selection method, it is possible to select frequencies as evenly as possible by removing previously used frequencies from search candidates.
[0017]
Further, according to the present invention, as described in claim 6, in the frequency selection method in the mobile station according to claim 5, when the frequency selection frequency reaches a predetermined number, the stored frequency is determined from a search candidate. It is characterized by removing.
[0018]
According to the present invention, the quality measurement means for measuring the quality of the frequency that may be used for communication, and the best quality among the frequencies measured by the quality measurement means are described. The difference in quality between the frequency and the best quality frequency is , Eliminate the bias of the selected frequency A selection candidate specifying unit that specifies a frequency within a predetermined range as a selection candidate; and a frequency selection unit that randomly selects a frequency to be used for communication from the frequencies specified by the selection candidate specifying unit. It is a featured mobile station.
[0019]
Further, according to the present invention, as described in claim 8, a quality measuring unit that measures the quality of a frequency that may be used for communication, and a predetermined quality or higher among the frequencies measured by the quality measuring unit. And a selection candidate specifying unit that specifies a frequency of the selected frequency as a selection candidate, and a frequency selection unit that randomly selects a frequency to be used for communication from the frequencies specified by the selection candidate specifying unit. Station.
[0020]
Further, according to the present invention, the quality measuring means for measuring the quality of a frequency that may be used for communication, and a frequency higher than a predetermined quality among the frequencies measured by the quality measuring means, as described in claim 9 And the quality difference between the best quality frequency and the best quality frequency is , Eliminate the bias of the selected frequency A selection candidate specifying unit that specifies a frequency within a predetermined range as a selection candidate, and a frequency selection unit that randomly selects a frequency to be used for communication from the frequencies specified by the selection candidate specifying unit. Mobile station.
[0021]
According to a tenth aspect of the present invention, in the mobile station according to the eighth or ninth aspect, the predetermined quality is a reference value that does not require a frequency change. Station.
[0022]
Further, according to the present invention, as described in claim 11, used frequency storage means for storing a frequency used in the past, and a mobile station uses a frequency other than the stored frequency for communication under a predetermined condition. Frequency selection means for selecting the frequency to be used.
[0023]
Further, according to the present invention, as described in claim 12, in the mobile station according to claim 11, when the frequency selection frequency reaches a predetermined number, the frequency selection unit determines the stored frequency. It is characterized by being excluded from search candidates.
[0024]
Further, the present invention as described in claim 13, a procedure for measuring a quality of a frequency that may be used for communication of a mobile station, a frequency of the best quality among the measured frequencies, The difference in quality from the best quality frequency , Eliminate the bias of the selected frequency A frequency selection program for causing a mobile station to execute a procedure for specifying a frequency within a predetermined range as a selection candidate and a procedure for randomly selecting a frequency to be used for communication by the mobile station from the specified frequencies. It is.
[0025]
According to the present invention, as described in claim 14, a procedure for measuring the quality of a frequency that may be used for communication of a mobile station, and a frequency of a predetermined quality or higher among the measured frequencies are selected. A frequency selection program for causing a mobile station to execute a procedure of specifying as a selection candidate and a procedure of randomly selecting a frequency to be used for communication by the mobile station from the specified frequencies.
[0026]
Further, the present invention is, as described in claim 15, a procedure for measuring the quality of a frequency that may be used for communication of a mobile station, and a predetermined quality or higher among the measured frequencies, And the quality difference between the best quality frequency and the best quality frequency is , Eliminate the bias of the selected frequency A frequency selection program for causing a mobile station to execute a procedure for specifying a frequency within a predetermined range as a selection candidate and a procedure for randomly selecting a frequency to be used for communication by the mobile station from the specified frequencies. is there.
[0027]
In addition, according to a sixteenth aspect of the present invention, in the frequency selection program according to the fourteenth or fifteenth aspect, the predetermined quality is a reference value that does not require a frequency change. This is a frequency selection program.
[0028]
Further, according to the present invention, as described in claim 17, a procedure for storing a frequency used in the past by the mobile station, and a mobile station uses a frequency other than the stored frequency for communication under a predetermined condition. A frequency selection program for causing a mobile station to execute a procedure of selecting as a power frequency.
.
[0029]
Further, according to the present invention, as described in claim 17, in the frequency selection program according to claim 17, when the frequency selection count reaches a predetermined number, the stored frequency is removed from the search candidates. Is a frequency selection program for causing a mobile station to execute
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration example of a mobile station to which a frequency selection method according to an embodiment of the present invention is applied. The mobile station 100 shown in the figure selects one frequency from frequencies that can be used for communication, and performs communication with a base station in a mobile communication system (not shown) using the frequency. The mobile station 100 includes an antenna 110, a transmission / reception unit 120, a control unit 130, a storage unit 140, an audio processing unit 150, a microphone 160, and a speaker 170.
[0031]
The transmission / reception unit 120 performs radio communication with the base station using a frequency obtained by frequency selection processing described later. The audio processing unit 150 performs the operation on the audio signal from the microphone 160. use Predetermined processing according to the communication method (voice encoding processing Reason ) And outputs the audio signal obtained as a result to the transceiver 120. The transmission / reception unit 120 transmits this audio signal via the antenna 110. In addition, the voice processing unit 150 performs the processing on the voice signal received by the transmission / reception unit 120. use Predetermined processing according to the communication method (sound Voice decoding processing). The signal obtained as a result is output to the speaker 170, and the speaker 170 performs audio output.
[0032]
The control unit 130 controls the transmission / reception unit 120 and the audio processing unit 150 to enable communication in the mobile station 100. Further, the control unit 130 has a quality measurement function 132, a selection candidate specifying function 134, and a frequency selection function 136. With these functions, a frequency selection process to be described later is performed and a standby operation is further performed. The storage unit 140 stores information (phone book, various constants, etc.) necessary for communication, and stores information (frequency transition unnecessary threshold, used frequency list, etc.) necessary for frequency selection processing described later.
[0033]
Hereinafter, frequency selection processing in the mobile station 100 will be described with reference to the first to fifth embodiments.
(First embodiment)
FIG. 2 is a flowchart showing the operation of the control unit 130 in the first embodiment. When the mobile station 100 is powered on (step 101), the control unit 130 sets measurement candidates (step 102). The measurement candidate is a frequency that may be used for communication, and is obtained by frequency search processing by the control unit 130. The frequency search process targets all frequencies that are likely to be used for communication and all frequencies that are likely to be used for communication. There are cases.
[0034]
Next, the control unit 130 measures the quality of the set measurement candidate (step 103). FIG. 3 is a diagram illustrating the correspondence between the position of the mobile station 100 and the frequency quality in the first embodiment. In the figure, base station 1 transmits a signal of frequency fA and a signal of frequency fC with the same power. Further, the base station 2 transmits a signal of frequency fB and a signal of frequency fC with the same power. When the mobile station 100 exists at the position P1, the frequency quality in the mobile station 100 is in the order of fC, fA, fB, and fD, and the values are as shown in FIG. 4, for example. On the other hand, when the mobile station 100 exists at the position P2, the quality of the frequency in the mobile station 100 is in the order of fC, fB, fA, and fD, and the values are as shown in FIG. 5, for example.
[0035]
Next, the control unit 130 specifies, as selection candidates, a frequency having the best quality and a frequency having a difference in quality between the frequency having the best quality within a predetermined range among the frequencies whose quality has been measured. (Step 104). Consider the case where the predetermined range is 3 dBm. When the mobile station 100 is present at the position P1 shown in FIG. 3 and the frequency quality at that position is as shown in FIG. 4, the control unit 130 selects the frequency fC having the quality of −60 dBm as the best quality. Recognize as a frequency. Further, the control unit 130 recognizes the frequency fA whose quality difference from the frequency fC is within 3 dBm. Then, the control unit 130 specifies the frequency fC and the frequency fA as selection candidates.
[0036]
On the other hand, when the mobile station 100 is present at the position P2 shown in FIG. 3 and the frequency quality at that position is as shown in FIG. 5, the control unit 130 selects the frequency fC having the quality of −70 dBm as the best. Recognize as a quality frequency. Furthermore, the control unit 130 recognizes the frequencies fA, fB, and fD whose quality difference from the frequency fC is within 3 dBm. Then, the control unit 130 specifies the frequency fC and the frequencies fA, fB, and fD as selection candidates.
[0037]
After specifying the selection candidates in this way, the control unit 130 randomly selects one frequency from these selection candidates (step 105). As described above, the selection candidate is a frequency in which the difference in quality between the frequency having the best quality and the frequency having the best quality is within a predetermined range. There is no significant difference in quality. Therefore, there is no problem even if the control unit 130 randomly selects one frequency from the selection candidates.
[0038]
Next, the control unit 130 receives broadcast information transmitted from the base station using the selected frequency, and performs a standby operation (step 106).
[0039]
As described above, in the first embodiment, the control unit 130 in the mobile station 100 measures the quality of the frequency that may be used for communication, and selects the best quality frequency from the measured frequencies. A frequency whose quality difference from the best quality frequency is within a predetermined range is specified as a selection candidate, and then a frequency to be used for communication by the mobile station 100 is randomly selected. Therefore, it is possible to select as many frequencies as possible as selection candidates and to select frequencies as equally as possible while not selecting all frequencies that can be used for communication as selection candidates.
(Second embodiment)
FIG. 6 is a flowchart showing the operation of the control unit 130 in the second embodiment. The operations in steps 201 to 203 are the same as the operations in steps 101 to 103 in FIG. That is, when the power of the mobile station 100 is turned on (step 201), the control unit 130 sets measurement candidates (step 202). Furthermore, the control unit 130 measures the quality of the set measurement candidate (step 203).
[0040]
Next, the control unit 130 determines whether or not there is a frequency having a quality better than a predetermined quality standard among the frequencies whose quality has been measured (step 204). When there is a frequency with a quality better than the predetermined quality standard, the control unit 130 identifies a frequency with a quality better than the predetermined quality standard as a selection candidate (step 205).
[0041]
FIG. 7 is a diagram illustrating the correspondence between the position of the mobile station 100 and the frequency quality. In FIG. 3, as in FIG. 3, the base station 1 transmits the signal of frequency fA and the signal of frequency fC with the same power, and the base station 2 transmits the signal of frequency fB and the signal of frequency fC to the same. Transmitting with power. 8 shows the quality of frequency in the mobile station 100 when the mobile station 100 exists at the position P1 in FIG. 7, and FIG. 9 shows the case where the mobile station 100 exists at the position P2 in FIG. The frequency quality in the mobile station 100 is shown. Here, the quality standard is assumed to be −75 dBm.
[0042]
When the mobile station 100 is present at the position P1 shown in FIG. 7, the frequencies fC and fA from the base station 1 are of quality exceeding the quality standard, and the quality of the frequencies fB and fD from the base station 2 is below the quality standard. It is. Therefore, in this case, the control unit 130 specifies the frequencies fC and fA as selection candidates. On the other hand, when the mobile station 100 exists at the position P2 shown in FIG. 7, the quality of the frequencies fC and fA from the base station 1 and the quality of the frequencies fB and fD from the base station 2 are both quality standards. Over. Therefore, the control unit 130 specifies the frequencies fA, fB, fC, and fD as selection candidates.
[0043]
Next, the control unit 130 randomly selects one frequency from the selection candidates (step 206). As described above, since the selection candidate is a frequency having a better quality than the quality standard, there is no problem in communication quality regardless of which frequency is selected. Therefore, there is no problem even if the control unit 130 randomly selects one frequency from the selection candidates.
[0044]
On the other hand, if the control unit 130 determines that there is no frequency with a quality higher than a predetermined quality standard, the control unit 130 selects the frequency with the best quality among the frequencies whose quality has been measured (step 207).
[0045]
Next, the control unit 130 receives broadcast information transmitted from the base station at the frequency selected in Step 206 or Step 207, and performs a standby operation (Step 208).
[0046]
As described above, in the second embodiment, the control unit 130 in the mobile station 100 measures the quality of frequencies that may be used for communication, and the quality of the measured frequency is higher than a predetermined quality standard. The mobile station 100 randomly selects a frequency that should be used for communication. Therefore, it is possible to select as many frequencies as possible as selection candidates and to select frequencies as equally as possible while not selecting all frequencies that can be used for communication as selection candidates.
(Third embodiment)
FIG. 10 is a flowchart showing the operation of the control unit 130 in the third embodiment. The operations in steps 301 to 303 are the same as the operations in steps 101 to 103 in FIG. That is, when the power of the mobile station 100 is turned on (step 301), the control unit 130 sets measurement candidates (step 302). Furthermore, the control unit 130 measures the quality of the set measurement candidate (step 303).
[0047]
Next, the control unit 130 determines whether or not there is a frequency having a quality better than a predetermined quality standard among the frequencies whose quality has been measured (step 304). When there is a frequency with a quality better than the predetermined quality standard, the control unit 130 has a quality better than the predetermined quality standard, and the quality with the frequency having the best quality and the frequency with the best quality. Are identified as selection candidates (step 305).
[0048]
Next, the control unit 130 randomly selects one frequency from the selection candidates (step 306). As described above, since the selection candidate is a frequency that has better quality than the quality standard and has the best quality and the frequency that has the best quality, the quality of communication is improved regardless of which frequency is selected. There is no problem and the difference is not great. Therefore, there is no problem even if the control unit 130 randomly selects one frequency from the selection candidates.
[0049]
On the other hand, if the control unit 130 determines that there is no frequency having a quality higher than a predetermined quality standard, the control unit 130 selects a frequency having the best quality among the frequencies whose quality has been measured (step 307).
[0050]
Next, the control unit 130 receives broadcast information transmitted from the base station at the frequency selected in Step 306 or Step 307, and performs a standby operation (Step 308).
[0051]
Thus, in the third embodiment, the control unit 130 in the mobile station 100 measures the quality of frequencies that may be used for communication, and the quality is higher than a predetermined quality standard from these measured frequencies. The frequency that the mobile station 100 should use for communication is determined after the frequency having the best quality and the frequency difference between the frequency having the best quality and the frequency having the best quality within a predetermined range are specified as selection candidates. Select at random. Therefore, it is possible to select as many frequencies as possible as selection candidates and to select frequencies as equally as possible while not selecting all frequencies that can be used for communication as selection candidates.
(Fourth embodiment)
FIG. 11 is a flowchart showing the operation of the control unit 130 in the fourth embodiment. When the power of the mobile station 100 is turned on (step 401), the control unit 130 determines whether or not a frequency transition unnecessary threshold is stored in the storage unit 140 (step 402). The frequency transition unnecessary threshold indicates a minimum value of frequency quality at which the mobile station 100 does not need to perform the handover process. That is, if the quality of the frequency used for communication by the mobile station 100 is equal to or higher than the frequency shift unnecessary threshold value, the handover process need not be performed. This frequency transition unnecessary threshold is included in the broadcast information transmitted from the base station when the mobile station 100 has previously performed communication.
[0052]
When the frequency shift unnecessary threshold is stored in the storage unit 140, the control unit 130 sets the frequency shift unnecessary threshold as a quality standard (step 403). On the other hand, when the frequency transition unnecessary threshold is not stored in the storage unit 140, the control unit 130 uses the preset quality standard as it is.
[0053]
The subsequent processing from step 404 to step 410 is the same as the processing from step 302 to step 308 in FIG. That is, the control unit 130 sets measurement candidates (step 404), and measures the quality of the set measurement candidates (step 405).
[0054]
Further, the control unit 130 determines whether or not there is a frequency having a quality better than a predetermined quality standard among the frequencies whose quality has been measured (step 406). When there is a frequency with a quality better than the predetermined quality standard, the control unit 130 has a quality better than the predetermined quality standard, and the quality with the frequency having the best quality and the frequency with the best quality. Are identified as selection candidates (step 407). Next, the control unit 130 randomly selects one frequency from the selection candidates (step 408). On the other hand, when the control unit 130 determines that there is no frequency with a quality higher than a predetermined quality standard, the control unit 130 selects the frequency with the best quality among the frequencies whose quality has been measured (step 409).
[0055]
Next, the control unit 130 receives broadcast information transmitted from the base station at the frequency selected in Step 408 or Step 409, and performs a standby operation (Step 410).
[0056]
Then, when the notification information includes a frequency shift unnecessary threshold value, the control unit 130 stores the frequency shift unnecessary threshold value in the storage unit 140 (step 411).
[0057]
As described above, in the fourth embodiment, as in the third embodiment, the control unit 130 in the mobile station 100 measures the quality of the frequency that may be used for communication, and selects from these measured frequencies. The mobile station 100 specifies a frequency having a quality better than a predetermined quality standard and having a difference in quality between the frequency having the best quality and the frequency having the best quality as a selection candidate. A frequency to be used for communication is selected at random. Therefore, it is possible to select as many frequencies as possible as selection candidates and to select frequencies as equally as possible while not selecting all frequencies that can be used for communication as selection candidates.
[0058]
Further, in the fourth embodiment, the control unit 130 selects a frequency having a better quality than the frequency transition unnecessary threshold, and therefore it is possible to prevent the frequency from being changed frequently and a load on the processing of the mobile station 100 from being applied. it can.
(5th Example)
FIG. 12 is a flowchart showing the operation of the control unit 130 in the fifth embodiment. When the power of the mobile station 100 is turned on (step 501), the control unit 130 determines whether or not the frequency used by the mobile station 100 in the past is stored in the storage unit 140 (step 502). Each frequency used by the mobile station 100 in the past is stored in the storage unit 140 as a used frequency list, for example. When the frequencies used by the mobile station 100 in the past are stored in the storage unit 140, the control unit 130 sets these frequencies as search candidates (step 503).
[0059]
Next, the control unit 130 increments the value of a built-in counter (not shown) by 1 (step 504), and further determines whether the value of the counter is an integral multiple of a predetermined value (step 505). When the value of the counter is an integer multiple of the predetermined value, the control unit 130 excludes all frequencies stored in the storage unit 140, that is, all frequencies used in the past from search candidates (step 506). When the value of the counter is not an integer multiple of the predetermined value, the control unit 130 does not perform this operation.
[0060]
Further, the control unit 130 searches for a search candidate frequency (step 507) and determines whether or not a frequency has been found (step 508). When the control unit 130 finds the frequency, the control unit 130 receives broadcast information transmitted from the base station using the found frequency and performs a standby operation (step 517).
[0061]
On the other hand, when determining that no frequency has been found in step 508, the control unit 130 sets all usable frequencies as search candidates (step 509). Further, the control unit 130 determines whether or not the value of the built-in counter is an integer multiple of a predetermined value (step 510). When the counter value is an integer multiple of the predetermined value, the control unit 130 excludes all frequencies stored in the storage unit 140 from search candidates (step 511). When the value of the counter is not an integer multiple of the predetermined value, the control unit 130 does not perform this operation.
[0062]
Further, the control unit 130 searches for a search candidate frequency (step 512) and determines whether or not a frequency has been found (step 513). When the control unit 130 finds the frequency, the control unit 130 receives broadcast information transmitted from the base station using the found frequency and performs a standby operation (step 517). Further, when the frequency is not found, the control unit 130 repeats the operation after the determination (step 502) after determining whether or not the frequency used by the mobile station 100 in the past is stored in the storage unit 140.
[0063]
If the control unit 130 determines in step 502 that the frequency used by the mobile station 100 in the past is not stored in the storage unit 140, the control unit 130 sets all usable frequencies as search candidates (step 514). Further, the control unit 130 searches for a search candidate frequency (step 515), and determines whether or not a frequency has been found (step 516). When the control unit 130 finds the frequency, the control unit 130 receives broadcast information transmitted from the base station using the found frequency and performs a standby operation (step 517). Further, when the frequency is not found, the control unit 130 repeats the operation after the determination (step 502) after determining whether or not the frequency used by the mobile station 100 in the past is stored in the storage unit 140.
[0064]
When determining that a plurality of frequencies are found in step 508, 513, or 516, the control unit 130 sets the plurality of found frequencies as selection candidates in step 517, and selects one of the selection candidates. Choose one frequency randomly.
[0065]
As described above, in the fifth embodiment, the control unit 130 excludes frequencies used in the past from search candidates, and can select frequencies as evenly as possible. In particular, in the fifth embodiment, every time the frequency selection count becomes an integral multiple of a predetermined value, the control unit 130 excludes the frequency used in the past from the search candidate and does not always exclude it from the search candidate. For this reason, the possibility of selecting the frequency used by the mobile station 100 immediately before that is expected to have the best quality among the frequencies used by the mobile station 100 in the past is ensured. Therefore, the control unit 130 can ensure the communication quality while removing the frequency used immediately before from the search candidates.
[0066]
In the first to fifth embodiments described above, the operation when the mobile station 100 is turned on has been described. However, the mobile station 100 moves from outside the service area of the mobile communication system into the service area. The same operation is performed also when it moves.
[0067]
【The invention's effect】
As described above, according to the present invention, it is possible to select the frequencies used by the mobile station for communication as evenly as possible.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a mobile station.
FIG. 2 is a flowchart showing an operation of a control unit in the first embodiment.
FIG. 3 is a diagram showing the correspondence between the position of a mobile station and frequency quality in the first embodiment.
4 is a diagram illustrating frequency quality at a position P1 in FIG. 3;
FIG. 5 is a diagram showing frequency quality at a position P2 in FIG. 3;
FIG. 6 is a flowchart showing the operation of a control unit in the second embodiment.
FIG. 7 is a diagram showing the correspondence between the position of a mobile station and frequency quality in the second embodiment.
8 is a diagram illustrating frequency quality at a position P1 in FIG.
FIG. 9 is a diagram illustrating frequency quality at a position P2 in FIG.
FIG. 10 is a flowchart showing the operation of a control unit in the third embodiment.
FIG. 11 is a flowchart showing the operation of a control unit in the fourth embodiment.
FIG. 12 is a flowchart showing the operation of a control unit in the fifth embodiment.
[Explanation of symbols]
100 mobile stations
110 Antenna
120 transceiver
130 Control unit
132 Quality measurement function
134 Selection candidate identification function
136 Frequency selection function
140 Storage unit
150 Speech processing unit
160 Microphone
170 Speaker

Claims (18)

  1. In a frequency selection method for selecting a frequency that a mobile station should use for communication in a mobile communication system,
    Measuring the quality of the frequencies that may be used for communication of the mobile station;
    A frequency of the best quality among the measured frequencies and a frequency in which a difference in quality between the frequency of the best quality is within a predetermined range that eliminates the bias of the selected frequency is specified as a selection candidate,
    A frequency selection method in a mobile station, wherein the mobile station randomly selects a frequency to be used for communication from the identified frequencies.
  2. In a frequency selection method for selecting a frequency that a mobile station should use for communication in a mobile communication system,
    Measuring the quality of the frequencies that may be used for communication of the mobile station;
    A frequency of a predetermined quality or higher is specified as a selection candidate from the measured frequencies,
    A frequency selection method in a mobile station, wherein the mobile station randomly selects a frequency to be used for communication from the identified frequencies.
  3. In a frequency selection method for selecting a frequency that a mobile station should use for communication in a mobile communication system,
    Measuring the quality of the frequencies that may be used for communication of the mobile station;
    A frequency that is equal to or higher than a predetermined quality among the measured frequencies and that has a difference in quality between the best quality frequency and the best quality frequency within a predetermined range that eliminates the bias of the selected frequency. Identify it as a candidate,
    A frequency selection method in a mobile station, wherein the mobile station randomly selects a frequency to be used for communication from the identified frequencies.
  4. In the frequency selection method in the mobile station according to claim 2 or 3,
    The frequency selection method in a mobile station, wherein the predetermined quality is a reference value that does not require frequency change.
  5. In a frequency selection method for selecting a frequency that a mobile station should use for communication in a mobile communication system,
    Store the frequency used by the mobile station in the past,
    A frequency selection method in a mobile station, wherein a frequency other than the stored frequency is selected as a frequency to be used for communication by the mobile station under a predetermined condition.
  6. The frequency selection method in the mobile station according to claim 5,
    A frequency selection method in a mobile station, wherein when the frequency selection frequency reaches a predetermined number, the stored frequency is excluded from search candidates.
  7. Quality measuring means for measuring the quality of frequencies that may be used for communication;
    Among the frequencies measured by the quality measuring means, the best quality frequency and the frequency in which the difference in quality between the best quality frequency is within a predetermined range that eliminates the bias of the selected frequency are selected candidates. Selection candidate specifying means for specifying as,
    Frequency selection means for randomly selecting a frequency to be used for communication from among the frequencies specified by the selection candidate specifying means;
    A mobile station comprising:
  8. Quality measuring means for measuring the quality of frequencies that may be used for communication;
    A selection candidate specifying means for specifying a frequency of a predetermined quality or higher as a selection candidate from the frequencies measured by the quality measuring means;
    Frequency selection means for randomly selecting a frequency to be used for communication from among the frequencies specified by the selection candidate specifying means;
    A mobile station comprising:
  9. Quality measuring means for measuring the quality of frequencies that may be used for communication;
    A predetermined quality which is equal to or higher than a predetermined quality among the frequencies measured by the quality measuring means, and a difference in quality between the best quality frequency and the best quality frequency eliminates the bias of the selected frequency. Selection candidate specifying means for specifying frequencies in the range as selection candidates;
    Frequency selection means for randomly selecting a frequency to be used for communication from among the frequencies specified by the selection candidate specifying means;
    A mobile station comprising:
  10. The mobile station according to claim 8 or 9,
    The mobile station characterized in that the predetermined quality is a reference value that does not require a frequency change.
  11. A used frequency storage means for storing a frequency used in the past;
    Frequency selection means for selecting a frequency other than the stored frequency as a frequency to be used by the mobile station for communication under a predetermined condition;
    A mobile station comprising:
  12. The mobile station according to claim 11, wherein
    The mobile station characterized in that the frequency selection means excludes the stored frequency from search candidates when the frequency of frequency selection reaches a predetermined number.
  13. Procedures to measure the quality of the frequencies that may be used for mobile station communication;
    A step of identifying, as a selection candidate, a frequency having the best quality among the measured frequencies and a frequency in which a difference in quality between the frequency of the best quality is within a predetermined range that eliminates a bias in the frequency to be selected; ,
    A procedure for randomly selecting a frequency to be used by the mobile station for communication from among the identified frequencies;
    For frequency selection to make mobile station execute.
  14. Procedures to measure the quality of the frequencies that may be used for mobile station communication;
    A procedure for specifying a frequency of a predetermined quality or higher as a selection candidate from the measured frequencies,
    A frequency selection program for causing a mobile station to execute a procedure of randomly selecting a frequency to be used for communication by the mobile station from the specified frequencies.
  15. Procedures to measure the quality of the frequencies that may be used for mobile station communication;
    A frequency that is equal to or higher than a predetermined quality among the measured frequencies and that has a difference in quality between the best quality frequency and the best quality frequency within a predetermined range that eliminates the bias of the selected frequency. A procedure to identify candidates for selection,
    A procedure for randomly selecting a frequency to be used by the mobile station for communication from among the identified frequencies;
    For frequency selection to make mobile station execute.
  16. The frequency selection program according to claim 14 or 15,
    The frequency selection program characterized in that the predetermined quality is a reference value that does not require a frequency change.
  17. A procedure for storing the frequency used by the mobile station in the past;
    A procedure for selecting a frequency other than the stored frequency as a frequency to be used by the mobile station for communication under a predetermined condition;
    For frequency selection to make mobile station execute.
  18. The frequency selection program according to claim 17,
    A frequency selection program for causing a mobile station to execute a procedure of removing a stored frequency from a search candidate when the number of frequency selections reaches a predetermined number.
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US8190163B2 (en) 2002-08-08 2012-05-29 Qualcomm Incorporated Methods and apparatus of enhanced coding in multi-user communication systems
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US20070211669A1 (en) * 2006-03-07 2007-09-13 Bhupesh Manoharlal Umatt Method and apparatus for searching radio technologies
JP2007318579A (en) * 2006-05-29 2007-12-06 Kyocera Corp Mobile communication system, base station device and interference wave determination method
JP4727528B2 (en) * 2006-07-28 2011-07-20 京セラ株式会社 Wireless communication method and base station control apparatus
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WO2008052123A1 (en) * 2006-10-25 2008-05-02 Qualcomm Incorporated Uniform out-of-service search for wireless communication systems
CN101637051B (en) 2007-01-11 2012-10-31 高通股份有限公司 Using dtx and drx in a wireless communication system
CN101772110B (en) * 2009-01-06 2015-01-28 中兴通讯股份有限公司 Inter-cell reselection method of femtocell
JP5863288B2 (en) * 2011-06-23 2016-02-16 株式会社日立国際電気 Mobile wireless communication device
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