JP2008136200A - Radio communication apparatus and frequency selecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent reception sensitivity from being rapidly deteriorated when moving to a peripheral cell by handover by selecting a frequency in consideration of the frequency of the peripheral cell. <P>SOLUTION: An RF unit 102 down-converts a signal received by an antenna 101 from a radio frequency to a baseband frequency. A frequency selection unit 106 selects a camera clock frequency based on receiving channel information stored in a memory 103. A timing control unit 108 multiplies and frequency-divides a reference clock. A timing control unit 110 further multiplies and frequency-divides a clock generated by the timing control unit 108 to generate an operating clock of the camera clock frequency. A camera unit 111 outputs image data to an image processing control unit 109 synchronously with the operating clock generated by the timing control unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to a radio communication apparatus and a frequency selection method for performing communication using different radio frequencies by performing handover to neighboring cells.

  Various communication devices having a reception function or a transmission function in recent years are equipped with a microcomputer, a digital signal processor (DSP), a special purpose LSI or the like for performing control or analysis of processing, Oscillating means for oscillating an LSI operation clock for driving the LSI or the like is also mounted. However, this LSI operation clock includes many harmonics, and if the harmonic components are mixed in the reception band or transmission band, the reception function or transmission function is disturbed. FIG. 15 is a diagram illustrating a state in which harmonics of the device operating frequency interfere with the radio frequency band.

  As a method of reducing such interference, a hardware measure for blunting the signal waveform by inserting a filter or the like in the signal line that causes interference can be considered. However, in this case, there are problems that the number of parts increases by inserting a filter or the like, and interference cannot be completely prevented.

Therefore, conventionally, it is known that the interference of the received wave is reduced by changing the frequency of the clock generated according to the radio frequency being used and supplying it to the CPU so that interference does not occur (for example, Patent Document 1).
JP 2000-341165 A

  However, in the conventional apparatus, since the frequency of the clock supplied to the device is selected based on only the radio frequency information currently being communicated, when the terminal moves to the neighboring cell, the reception sensitivity is rapidly deteriorated. There is a problem that can cause. Some devices can change the frequency only when the device is activated. Even if the frequency can be changed dynamically after the device is activated, the frequency is used based on the frequency information used by the neighboring cell at the time of handover to the neighboring cell. Therefore, there is a problem in that the reception sensitivity is deteriorated during the period from handover to resetting the frequency.

  The present invention has been made in view of the above points, and by selecting a frequency in consideration of the frequency of the neighboring cell, it is possible to prevent a sudden deterioration in reception sensitivity when moving to the neighboring cell by handover. An object of the present invention is to provide a wireless communication device and a frequency selection method that can be used.

  The radio communication apparatus of the present invention includes a storage unit that stores reception channel information that is information on a radio frequency used in each cell, and a frequency selection unit that selects an operating frequency that does not interfere with the radio frequency based on the reception channel information. And a timing control unit that generates an operation clock having the operation frequency selected by the frequency selection unit and operates the device using the generated operation clock.

  In the frequency selection method of the present invention, an operating frequency that does not interfere with the radio frequency is selected based on reception channel information, which is information on the radio frequency used in each cell.

  According to the present invention, by selecting the frequency in consideration of the frequency of the neighboring cell, it is possible to prevent a sudden deterioration in reception sensitivity when moving to the neighboring cell by handover.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of radio communication apparatus 100 according to Embodiment 1 of the present invention.

  The reception quality measurement unit 104, the handover unit 105, the frequency selection unit 106, the reference clock supply unit 107, the timing control unit 108, and the image processing control unit 109 constitute a CPU 150. The timing control unit 110 and the camera unit 111 constitute a camera module 160. In the present embodiment, a case where the camera module 160 is a device to which an operation clock is supplied will be described.

  The antenna 101 receives a signal with a predetermined radio frequency and outputs it to the RF unit 102.

  The RF unit 102 down-converts the reception signal input from the antenna 101 from a radio frequency to a baseband frequency and outputs the result to the reception quality measurement unit 104.

  The memory 103 which is a storage means stores information on the radio frequency used in the currently communicating cell and reception channel information which is information on the radio frequency used in the neighboring cells which are the surrounding cells of the currently communicating cell. is doing. That is, the reception channel information is information on the radio frequency used in each cell.

  Reception quality measuring section 104 measures the reception quality of the received signal input from RF section 102 and outputs the measurement result to handover section 105.

  The handover unit 105 refers to the measurement result input from the reception quality measurement unit 104, and among the cells using the radio frequency of the reception channel information stored in the memory 103, the neighboring cell whose measurement result is equal to or greater than the threshold value Hand over to.

  The frequency selection unit 106 reads out the reception channel information from the memory 103 and uses it when operating the camera module 160 based on the read out reception channel information and the handover destination neighboring cell notified from the handover unit 105. A camera clock frequency (operation frequency) that does not interfere with the radio frequency of the reception channel information is selected. Then, the frequency selection unit 106 controls the timing control unit 108 and the timing control unit 110 to generate an operation clock having the selected camera clock frequency. A method for selecting the camera clock frequency will be described later.

  The reference clock supply unit 107 generates a reference clock having a reference frequency for operating the CPU 150, and outputs the generated reference clock to the timing control unit 108.

  The timing control unit 108 is, for example, a multiplication / division circuit, and multiplies and divides the reference clock input from the reference clock supply unit 107 under the control of the frequency selection unit 106 to perform image processing control unit 109 and timing control unit 110. Output to. Details of the configuration of the timing control unit 108 will be described later.

  Based on the clock input from the timing control unit 108, the image processing control unit 109 performs image processing on image data input from the camera unit 111 described later and outputs the processed image data to the display unit 112.

  The timing control unit 110 is, for example, a multiplication / division circuit, and further multiplies and divides the clock input from the timing control unit 108 as a reference clock according to the control of the frequency selection unit 106 to operate the camera module 160. The operation clock of the camera clock frequency is generated. Then, the timing control unit 110 outputs the generated operation clock to the camera unit 111 to control the image data to be output from the camera unit 111 in synchronization with the camera clock frequency. Details of the configuration of the timing control unit 110 will be described later.

  The camera unit 111 captures an image and outputs image data of the captured image to the image processing control unit 109 according to control by the timing control unit 110.

  The display unit 112 displays an image of the image processed image data input from the image processing control unit 109.

  Next, details of the configuration of the timing control unit 108 will be described with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the timing control unit 108.

  The phase comparator 201 compares the phase of the reference clock input from the reference clock supply unit 107 with the phase of the divided clock input from the frequency divider 204 to detect a phase difference, and outputs the detected phase difference. To do.

  The LPF 202 converts the phase difference signal input from the phase comparator 201 into a direct current (cuts off high-frequency components) and outputs it to the VCO 203.

  The VCO 203 outputs a clock having a predetermined frequency to the timing control unit 110 and the frequency divider 204 by controlling the transmission frequency with the DC signal input from the LPF 202.

  The frequency divider 204 divides the clock input from the VCO 203 and outputs it to the phase comparator 201.

  Next, details of the configuration of the timing control unit 110 will be described with reference to FIG. FIG. 3 is a block diagram illustrating a configuration of the timing control unit 110.

  The phase comparator 301 detects the phase difference by comparing the phase of the multiplied and divided clock input from the timing control unit 108 with the phase of the divided clock input from the frequency divider 304. Output the phase difference.

  The LPF 302 converts the phase difference signal input from the phase comparator 301 into a direct current (cuts off high-frequency components) and outputs it to the VCO 303.

  The VCO 303 generates an operation clock having the camera clock frequency of the camera module 160 by controlling the transmission frequency by the DC signal input from the LPF 302, and outputs the generated operation clock to the camera unit 111.

  The frequency divider 304 divides the operation clock input from the VCO 303 and outputs it to the phase comparator 301.

  Next, the operation of radio communication apparatus 100 will be described using FIG. FIG. 4 is a flowchart showing the operation of the wireless communication device 100.

  First, when the camera icon on the menu screen displayed on the display unit 112 of the wireless communication apparatus 100 is selected, the camera module 160 is activated (step ST401).

  Next, frequency selection section 106 of radio communication apparatus 100 acquires reception channel information from memory 103 (step ST402). For example, the frequency selection unit 106 acquires reception channel information of three radio frequencies FID1, FID2, and FID3 as reception channel information. Here, it is assumed that FID1 is a radio frequency of a cell with which the radio communication apparatus 100 is communicating, and FID2 and FID3 are radio frequencies used in neighboring cells that are handover candidates.

  Next, frequency selection section 106 calculates the distance between the preset frequency of the camera clock multiplied wave and the radio frequency of the reception channel information (step ST403). Here, the distance is an interval between each frequency on the frequency axis. For example, when four frequencies F1, F2, F3, and F4 are set as camera clocks, the frequency selection unit 106 has three radio frequencies FID1, FID2, and FID3, and F1, F2, F3, and F4. Calculate the distance to each of the four camera clock frequencies. That is, the frequency selection unit 106 calculates the distance for each combination in 12 combinations of frequencies using the equation (1).

FIDn ÷ Fm = Q ・ ・ ・ a
fsp nm = a (when a <(Fm / 2))
fsp nm = Fm−a (when a> = (Fm / 2)) (1)
Where n is a radio frequency (n is an arbitrary natural number, n = 1, 2, 3 in the first embodiment)
m is a camera clock frequency (m is an arbitrary natural number, and m = 1, in the first embodiment.
2,3,4)
Q is the quotient a is the remainder fsp is the distance between the frequency of the multiplied wave of the camera clock (F1 to F4) and the radio frequency of the reception channel information (FID1 to FID3)

  FIG. 5 is a diagram illustrating a distance calculation method in the frequency selection unit 106. In FIG. 5, F1 × N (candidate frequency) represents the frequency of the harmonic signal component of the camera clock frequency F1, and F2 × N (candidate frequency) represents the frequency of the harmonic signal component of the camera clock frequency F2. F3 × N (candidate frequency) represents the frequency of the harmonic signal component of the camera clock frequency F3, and F4 × N (candidate frequency) represents the frequency of the harmonic signal component of the camera clock frequency F4. Is shown. From FIG. 5, the frequency selection unit 106, for the radio frequency FID1, the distance R1 from the radio frequency FID1 to the camera clock frequency F1 × N, the distance R2 from the radio frequency FID1 to the camera clock frequency F2 × N, and the radio frequency Calculation is performed for each of the distance R3 from FID1 to the camera clock frequency F3 × N and the distance R4 from the radio frequency FID1 to the camera clock frequency F4 × N. Moreover, the frequency selection part 106 calculates similarly about radio frequency FID2 and radio frequency FID3.

  Here, the frequency band F500 is a band in which data is present when communication is performed using the radio frequency FID1. In the case of, for example, the W-CDMA system in which transmission data is spread using a predetermined spreading code, the frequency band F500 is a band in which data is spread in the frequency axis direction by spreading processing. Further, the frequency band F500 is a frequency that interferes with the radio frequency FID1.

  Returning to FIG. 4, next, the frequency selection unit 106 weights each distance calculated in step ST403 (step ST404). Specifically, the frequency selection unit 106 performs weighting according to equation (2).

  6 to 8 are diagrams showing a method of weighting each distance calculated in step ST403. 6 is a diagram showing a weighting method in the case of the radio frequency FID1, FIG. 7 is a diagram showing a weighting method in the case of the radio frequency FID2, and FIG. 8 is a weighting method in the case of the radio frequency FID3. It is a figure which shows a method. 6 to 8, F1 × N indicates the frequency of the harmonic signal component of the camera clock frequency F1, and F2 × N indicates the frequency of the harmonic signal component of the camera clock frequency F2. F3 × N represents the frequency of the harmonic signal component of the camera clock frequency F3, and F4 × N represents the frequency of the harmonic signal component of the camera clock frequency F4. 6 to 8, it is assumed that the wireless communication device 100 is currently performing communication in a cell using the radio frequency FID1.

  In the case of the radio frequency FID1, the distance R1 from the radio frequency FID1 to F1 × N is larger than the band F601-1 from FIG. On the other hand, the distance R2 from the radio frequency FID1 to F2 × N, the distance R3 from the radio frequency FID1 to F3 × N, and the distance R4 from the radio frequency FID1 to F4 × N are from the band F601-1 or the band F601-2. Is also small. Accordingly, only the harmonic signal component F1 × N of the camera clock frequency F1 is a frequency that is not included in the band F601 in which the data of the radio frequency FID1 exists, and the harmonics of the other camera clock frequencies F2, F3, and F4. The signal components F2 × N, F3 × N, and F4 × N are frequencies included in a band F601 in which data of the radio frequency FID1 exists. Therefore, the frequency selection unit 106 sets the weight of the camera clock frequency F1 to “1”, sets the weight of the camera clock frequency F2 to “0”, sets the weight of the camera clock frequency F3 to “0”, and sets the camera clock frequency F4 to The weight is set to “0”.

  In the case of the radio frequency FID2, from FIG. 7, the distance R2 from the radio frequency FID2 to F2 × N, the distance R3 from the radio frequency FID2 to F3 × N, and the distance R4 from the radio frequency FID2 to F4 × N. Is larger than the band F701-1. On the other hand, the distance R1 from the radio frequency FID2 to F1 × N is smaller than the band F701-1. Accordingly, only the harmonic signal component F1 × N of the camera clock frequency F1 is a frequency included in the band F701 where the data of the radio frequency FID2 exists, and the harmonic signal components of the other camera clock frequencies F2, F3, and F4. F2 × N, F3 × N, and F4 × N are frequencies that are not included in the band F701 where the data of the radio frequency FID2 exists. Accordingly, the frequency selection unit 106 sets the weight of the camera clock frequency F1 to “0”, sets the weight of the camera clock frequency F2 to “1”, sets the weight of the camera clock frequency F3 to “1”, and sets the camera clock frequency F4 to The weight is set to “1”.

  In the case of the radio frequency FID3, from FIG. 8, the distance R2 from the radio frequency FID3 to F2 × N, the distance R3 from the radio frequency FID3 to F3 × N, and the distance R4 from the radio frequency FID3 to F4 × N. Is larger than the band F801-2. On the other hand, the distance R1 from the radio frequency FID3 to F1 × N is smaller than the band F801-2. Accordingly, only the harmonic signal component F1 × N of the camera clock frequency F1 is a frequency included in the band F801 where the data of the radio frequency FID3 exists, and the harmonic signal components of the other camera clock frequencies F2, F3, and F4. F2 × N, F3 × N, and F4 × N are frequencies that are not included in the band F801 in which data of the radio frequency FID3 exists. Accordingly, the frequency selection unit 106 sets the weight of the camera clock frequency F1 to “0”, sets the weight of the camera clock frequency F2 to “1”, sets the weight of the camera clock frequency F3 to “1”, and sets the camera clock frequency F4 to The weight is set to “1”.

  The frequency selection unit 106 adds up the weights obtained in FIGS. At that time, since the currently used radio frequency is FID1, the frequency selecting unit 106 preferentially selects a camera clock frequency that generates a harmonic that does not interfere with the radio frequency FID1 with respect to all the weights of FID1. Multiply by the coefficient “3” for As a result, the frequency selection unit 106 obtains a weighting result as shown in FIG. Then, the frequency selection unit 106 obtains the weighted addition value W [m] using the equation (3), and selects F1 having the largest weighting addition value as the camera clock frequency.

  Returning to FIG. 4 again, next, the frequency selection unit 106 determines whether or not there is only one camera clock frequency Fm at which the weighted addition value W [m] is maximum (step ST405).

  In the case of FIGS. 6 to 8, since the camera clock frequency Fm that maximizes the weighted addition value W [m] is only one of F1, the frequency selection unit 106 sets the optimum camera clock frequency to F1. Determine (step ST406).

  Next, frequency selection section 106 sets the multiplication / division ratio of timing control section 108 and timing control section 110 such that the camera clock frequency becomes F1 (step ST407).

  Next, the timing control unit 108 and the timing control unit 110 divide and multiply the clock by the set multiplication / division ratio to generate an operation clock having the camera clock frequency F1. As a result, the operation clock with which the image data output from the camera unit 111 to the image processing control unit 109 is synchronized is the camera clock frequency F1, so that the harmonic generated from the signal line 120 interferes with the received signal on the signal line 130. Can be prevented.

  On the other hand, in step ST405, when there are two or more camera clock frequencies Fm at which the weighted addition value W [m] is maximized, the frequency selection unit 106 has the weighted addition value W [m] maximized. A frequency having the maximum distance among the camera clock frequencies Fm is selected as the camera clock frequency. That is, the frequency selection unit 106 selects the frequency at which the distance fsp 1m to the FID 1 is the maximum as the camera clock frequency.

  Incidentally, when the coefficient for multiplying the weight by the frequency selection unit 106 is “2”, the weighted addition value W [m] of F1 is also “2” in FIG. m] becomes “2” at all camera clock frequencies. In this case, the frequency selection unit 106 generates a harmonic that interferes with the frequency FID1 without selecting the camera clock frequency F1 that generates a harmonic that does not interfere with the frequency FID1 currently used in the currently communicating cell. There is a possibility of selecting camera clock frequencies F2, F3, F4. Therefore, it is preferable to set the coefficient by which the weight is multiplied to “3”. The coefficient to be multiplied by the weight is not limited to “3”, and the coefficient to be multiplied by the weight can be set to an arbitrary value such as “4” or “5” according to the degree of interference.

  The radio frequency is usually in the 800 MHz band to 2 GHz band, and when the camera clock frequencies F1 to F4 are several tens of MHz, the camera clock frequencies F1 to F4 and the radio frequency do not interfere with each other. However, interference degradation occurs when the frequency of the harmonic component generated from the camera clock frequencies F1 to F4, which is N times the camera clock frequencies F1 to F4 (N is an arbitrary natural number), interferes with the radio frequency. That is, when the camera clock (square wave) is Fourier-transformed, the harmonic component signal appearing on the frequency axis interferes with the radio frequency.

  FIGS. 10A to 10D are diagrams illustrating signal levels on the radio band of the harmonic signal components of the camera clock frequencies F1 to F4. FIG. 10A is a diagram showing the signal level on the radio band of the harmonic signal component of the camera clock frequency F1, and FIG. 10B is the radio signal level of the harmonic signal component on the camera clock frequency F2. FIG. 10C is a diagram showing the signal level on the radio band of the harmonic signal component of the camera clock frequency F3, and FIG. 10D is the harmonic of the camera clock frequency F4. It is a figure which shows the signal level on the radio | wireless band of a wave signal component.

  The signal level on the radio band of the harmonic signal components of the camera clock frequencies F1 to F4 appears as an interference component in the radio band as it is. For example, the channel frequency of FID1 is 2155 MHz, the channel frequency of FID2 is 2135 MHz, and the channel frequency of FID3 is 2120 MHz. The case will be described. When the clock frequency of the device is selected only from the currently used channel frequency (FID frequency) as in the prior art, when the used channel frequency is 2155 MHz, the signal level (RSSI) of the high frequency signal component is F4, F2, Since F3 and F1 increase in order (d1 <b1 <c1 <a1), the camera clock frequency F4 having the lowest signal level of the harmonic signal component is selected.

  In the first embodiment, from equation (3), W [1] = 2, W [2] = 3, W [3] = 3, and W [4] = 2, and the maximum weighted addition value is obtained. Becomes two (W [2] = W [3] = 3). Here, from the equation (1), since fsp 12> fsp 13, the frequency selection unit 106 selects the camera clock frequency F2. On the other hand, when the reception frequency is 2135 MHz, the signal level of the harmonic signal component increases in the order of F3, F2, F1, and F4 (c2 <b2 <d2 <a2), and when 2120 MHz, the signal level of the harmonic signal component is F3, F1, F2, and F4 increase in this order (c3 <a3 <b3 <d3). Therefore, when the reception frequencies are 2135 MHz and 2120 MHz, the harmonic signal component of the camera clock frequency F4 is large, so the frequency selection unit 106 does not select the camera clock frequency F4. As a result, the wireless communication device 100 does not cause a sudden deterioration in sensitivity even when moving to a neighboring cell.

  As described above, according to the first embodiment, by selecting the camera clock frequency in consideration of the frequency of the neighboring cell, when the mobile phone moves to the neighboring cell by the handover, the reception sensitivity is rapidly deteriorated. Can be prevented. Further, according to the first embodiment, weighting is performed according to the calculated distance on the frequency axis, so that a more optimal camera clock frequency can be selected. Further, according to the first embodiment, since the coefficient is multiplied by the weight of the radio frequency used in the currently communicating cell, the camera that does not interfere with the radio frequency used in the currently communicating cell. Since the clock frequency is easily selected, the optimum camera clock frequency can be selected even when handover is not performed. Further, according to the first embodiment, the coefficient for multiplying the weight of the radio frequency used in the currently communicating cell is set to “3”, so that an optimum camera clock frequency is selected even when handover is not performed. At the same time, an optimal camera clock frequency can be selected even in the case of handover.

(Embodiment 2)
FIG. 11 is a block diagram showing a configuration of radio communication apparatus 1100 according to Embodiment 2 of the present invention. In this embodiment, the case where the display portion 1102 is a device to which an operation clock is supplied will be described.

  The wireless communication apparatus 1100 according to the second embodiment is the same as the wireless communication apparatus 100 according to the first embodiment shown in FIG. 1, except for the timing control section 110 and the camera section 111, as shown in FIG. A timing control unit 1101 is provided instead of 108, and a display unit 1102 is provided instead of the display unit 112. In FIG. 11, parts having the same configuration as in FIG.

  The frequency selection unit 106 reads out reception channel information from the memory 103, and is used when the display unit 1102 such as an LCD is operated based on the read reception channel information, and does not interfere with the radio frequency of the reception channel information. Select the clock frequency (operating frequency). Then, the frequency selection unit 106 controls the timing control unit 1101 to generate an operation clock having the selected pixel clock frequency. A method for selecting the pixel clock frequency will be described later.

  The reception quality measurement unit 104, the handover unit 105, the frequency selection unit 106, the reference clock supply unit 107, the image processing control unit 109, and the timing control unit 1101 constitute a CPU 1150.

  The timing control unit 1101 is, for example, a multiplication / division circuit, and a pixel clock selected by the frequency selection unit 106 by multiplying and dividing the reference clock input from the reference clock supply unit 107 according to the control of the frequency selection unit 106. An operation clock having a frequency is output to the display unit 1102.

  The image processing control unit 109 performs image processing of predetermined image data based on the clock input from the timing control unit 1101 and outputs the image data to the display unit 1102.

  A display unit 1102 is a liquid crystal display device, and displays an image of image data input from the image processing control unit 109. Further, the display unit 1102 performs display processing in synchronization with the pixel clock frequency of the operation clock supplied from the timing control unit 1101 when displaying. The configuration of the timing control unit 1101 is the same as that shown in FIG.

  Next, the operation of the wireless communication apparatus 1100 will be described using FIG. FIG. 12 is a flowchart showing the operation of the wireless communication device 1100.

  First, the liquid crystal of the display unit 1102 is activated by opening the flip of the wireless communication device 1100 (step ST1201).

  Next, frequency selection section 106 of wireless communication apparatus 1100 acquires reception channel information from memory 103 (step ST1202). For example, the frequency selection unit 106 acquires reception channel information of three frequencies FID1, FID2, and FID3 as reception channel information.

  Next, frequency selection section 106 calculates the distance between the preset frequency of the pixel clock multiplied wave and the radio frequency of the reception channel information (step ST1203). Here, the distance is an interval between each frequency on the frequency axis. For example, when four frequencies F1, F2, F3, and F4 are set as pixel clocks, the frequency selection unit 106 has three radio frequencies FID1, FID2, and FID3, and F1, F2, F3, and F4. Calculate the distance to each of the four frequencies. That is, the frequency selection unit 106 calculates the distance for each combination in 12 combinations of frequencies using the equation (1).

  Next, frequency selection section 106 weights each distance calculated in step ST1203 (step ST1204). Specifically, the frequency selection unit 106 performs weighting according to equation (2).

  Next, the frequency selection unit 106 determines whether there is only one pixel clock frequency Fm that maximizes the weighted addition value W [m] (step ST1205).

  The frequency selection unit 106 determines the optimum pixel clock frequency Fm when there is only one pixel clock frequency Fm that maximizes the weighted addition value W [m] (step ST1206).

  Next, the frequency selection unit 106 sets the multiplication / division ratio of the timing control unit 1101 so that the optimum pixel clock frequency Fm is obtained (step ST1207).

  Next, the timing control unit 1101 divides and multiplies the input signal by the set multiplication / division ratio to generate an operation clock having the pixel clock frequency Fm. As a result, the operation clock with which the signal output from the CPU 1150 to the display unit 1102 is synchronized is the pixel clock frequency Fm, so that the harmonics generated from the signal line 1120 and the reception signal of the signal line 130 can be prevented from interfering with each other. it can.

  On the other hand, in step ST1205, when there are two or more pixel clock frequencies Fm at which the weighted addition value W [m] is maximized, the frequency selection unit 106 maximizes the weighted addition value W [m]. Of the pixel clock frequencies Fm, the frequency that maximizes the distance is selected as the pixel clock frequency (step ST1208). That is, the frequency selection unit 106 selects a frequency that maximizes the distance fsp_1m to the FID1 as the pixel clock frequency.

  As described above, according to the second embodiment, by selecting the pixel clock frequency in consideration of the frequency of the neighboring cell, when the mobile station moves to the neighboring cell by the handover, the reception sensitivity is rapidly deteriorated. Can be prevented. Further, according to the second embodiment, weighting is performed according to the calculated distance on the frequency axis, so that a more optimal pixel clock frequency can be selected. Further, according to the second embodiment, the weighting of the radio frequency used in the currently communicating cell is multiplied by a coefficient, so that the pixel does not interfere with the radio frequency used in the currently communicating cell. Since the clock frequency is easily selected, the optimum pixel clock frequency can be selected even when handover is not performed. Further, according to the second embodiment, the coefficient for multiplying the weight of the radio frequency used in the currently communicating cell is set to “3”, so that an optimum pixel clock frequency is selected even when handover is not performed. At the same time, an optimal pixel clock frequency can be selected even in the case of handover.

(Embodiment 3)
FIG. 13 is a block diagram showing a configuration of radio communication apparatus 1300 according to Embodiment 3 of the present invention. In this embodiment, the case where the memory card unit 1303 is a device to which an operation clock is supplied will be described.

  As shown in FIG. 13, wireless communication apparatus 1300 according to the third embodiment is similar to wireless communication apparatus 100 according to the first embodiment shown in FIG. 1, and includes image processing control unit 109, timing control unit 110, and camera unit 111. Except for the display unit 112, a memory card data processing unit 1302 and a memory card unit 1303 are added, and a timing control unit 1301 is provided instead of the timing control unit 108. In FIG. 13, parts having the same configuration as in FIG.

  The frequency selection unit 106 reads out the reception channel information from the memory 103 and is used when operating the memory card unit 1303 based on the read out reception channel information, and does not interfere with the radio frequency of the reception channel information. Select the clock frequency (operating frequency). The frequency selection unit 106 controls the timing control unit 1301 to generate an operation clock having the selected memory card clock frequency. A method for selecting the memory card clock frequency will be described later.

  The timing control unit 1301 is, for example, a multiplication / division circuit, and a memory card selected by the frequency selection unit 106 by multiplying and dividing the reference clock input from the reference clock supply unit 107 under the control of the frequency selection unit 106. The operating clock frequency is output to the memory card unit 1301 and the memory card data processing unit 1302.

  The memory card data processing unit 1302 processes data input from the memory card unit 1303 based on the operation clock input from the timing control unit 1301 and outputs predetermined data to the memory card unit 1303.

  The memory card unit 1303 is a memory card device having a socket that is electrically and mechanically connected to the inserted memory card, and the socket is synchronized with the clock frequency for the memory card of the operation clock input from the timing control unit 1301. Data is read from the memory card inserted into the memory card or data is written to the memory card inserted into the socket. Then, the memory card unit 1303 outputs the data read from the memory card to the memory card data processing unit 1302. The configuration of the timing control unit 1301 is the same as that shown in FIG.

  Next, the operation of the wireless communication apparatus 1300 will be described using FIG. FIG. 14 is a flowchart showing the operation of the wireless communication device 1300.

  First, by inserting a memory card into the memory card unit 1303 of the wireless communication apparatus 1300, it is possible to read data from the inserted memory card and write data to the inserted memory card (read / read). Write start) (step ST1401).

  Next, frequency selection section 106 of radio communication apparatus 1300 acquires reception channel information from memory 103 (step ST1402). For example, the frequency selection unit 106 acquires reception channel information of three frequencies FID1, FID2, and FID3 as reception channel information.

  Next, frequency selection section 106 calculates the distance between the preset frequency of the multiplied frequency of the memory card clock and the radio frequency of the reception channel information (step ST1403). Here, the distance is an interval between each frequency on the frequency axis. For example, when four frequencies F1, F2, F3, and F4 are set as clocks for the memory card, the frequency selection unit 106 has three radio frequencies FID1, FID2, and FID3, F1, F2, and F3. Calculate the distance to each of the four frequencies of F4. That is, the frequency selection unit 106 calculates the distance for each combination in 12 combinations of frequencies using the equation (1).

  Next, frequency selection section 106 weights each distance calculated in step ST1403 (step ST1404). Specifically, the frequency selection unit 106 performs weighting according to equation (2).

  Next, frequency selection section 106 determines whether or not there is only one memory card clock frequency Fm that maximizes the weighted addition value W [m] (step ST1405).

  When only one memory card clock frequency Fm has the maximum weighted addition value W [m], the frequency selection unit 106 determines the optimum memory card clock frequency Fm (step ST1406).

  Next, the frequency selection unit 106 sets the multiplication / division ratio of the timing control unit 1301 so that the optimum memory card clock frequency Fm is obtained (step ST1407).

  Next, the timing control unit 1301 divides and multiplies the input signal by the set multiplication / division ratio and generates an operation clock having the memory card clock frequency Fm. As a result, the operation clock that synchronizes the data output from the memory card unit 1303 to the memory card data processing unit 1302 is the memory card clock frequency Fm, so that the harmonics generated from the signal line 1320 and the received signal on the signal line 130 Can be prevented from interfering.

  On the other hand, in step ST1405, when there is not only one memory card clock frequency Fm that maximizes the weighted addition value W [m], the frequency selection unit 106 sets the weighted addition value W [m] to the maximum. The frequency at which the distance is maximum among the memory card clock frequencies Fm is selected as the memory card clock frequency (step ST1408). That is, the frequency selection unit 106 selects the frequency at which the distance fsp 1m to the FID 1 is the maximum as the memory card clock frequency.

  As described above, according to the third embodiment, by selecting the frequency in consideration of the frequency of the neighboring cell, it is possible to prevent a sudden deterioration in reception sensitivity when moving to the neighboring cell by handover. Can do. Further, according to the third embodiment, since weighting is performed according to the calculated distance on the frequency axis, a more optimal memory card clock frequency can be selected. Further, according to the third embodiment, since the coefficient is multiplied by the weight of the radio frequency used in the currently communicating cell, the memory that does not interfere with the radio frequency used in the currently communicating cell. Since the card clock frequency is easily selected, the optimum memory card clock frequency can be selected even when handover is not performed. Further, according to the third embodiment, the coefficient for multiplying the weighting of the radio frequency used in the currently communicating cell is set to “3”, so that the optimum memory card clock frequency even when no handover is performed. Can be selected at the same time, and an optimum memory card clock frequency can be selected even in the case of handover.

  Some devices may not be able to follow the frequency after switching when switching the frequency used by the timing control unit at the timing before and after the handover. In such a case, the device should have two timing control units, a first timing control unit that performs control at the frequency before the handover and a second timing control unit that performs control at the frequency after the handover. Can do. Then, the second timing control unit prepares to switch to the frequency to be used after the handover before the handover is completed, and switches the frequency when preparation for switching the frequency is completed (after stabilization). Further, such a device may be configured such that the frequency is not switched during activation but is switched only before activation.

  The radio communication apparatus and frequency selection method according to the present invention are particularly suitable for performing communication using different radio frequencies by performing handover to neighboring cells.

1 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 1 of the present invention. The block diagram which shows the structure of the timing control part which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the timing control part which concerns on Embodiment 1 of this invention. FIG. 3 is a flowchart showing the operation of the wireless communication apparatus according to the first embodiment of the present invention. The figure which shows the calculation method of the distance which concerns on Embodiment 1 of this invention. The figure which shows the weighting method which concerns on Embodiment 1 of this invention. The figure which shows the weighting method which concerns on Embodiment 1 of this invention. The figure which shows the weighting method which concerns on Embodiment 1 of this invention. The figure which shows the weighting method which concerns on Embodiment 1 of this invention. The figure which shows the relationship between the radio frequency and RSSI which concern on Embodiment 1 of this invention. The figure which shows the relationship between the radio frequency and RSSI which concern on Embodiment 1 of this invention. The figure which shows the relationship between the radio frequency and RSSI which concern on Embodiment 1 of this invention. The figure which shows the relationship between the radio frequency and RSSI which concern on Embodiment 1 of this invention. FIG. 2 is a block diagram showing a configuration of a wireless communication apparatus according to Embodiment 2 of the present invention. FIG. 7 is a flowchart showing the operation of the wireless communication apparatus according to the second embodiment of the present invention. Block diagram showing a configuration of a wireless communication apparatus according to Embodiment 3 of the present invention FIG. 9 is a flowchart showing the operation of the wireless communication apparatus according to the third embodiment of the present invention. Figure showing how the harmonics of the conventional device operating frequency interfere with the radio frequency band

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 101 Antenna 102 RF part 103 Memory 104 Reception quality measurement part 105 Handover part 106 Frequency selection part 107 Reference clock supply part 108,110 Timing control part 109 Image processing control part 111 Camera part 112 Display part 150 CPU
160 Camera module

Claims (21)

Storage means for storing reception channel information which is radio frequency information used in each cell;
Frequency selection means for selecting an operating frequency that does not interfere with the radio frequency based on the reception channel information;
A timing control unit that generates an operation clock of the operation frequency selected by the frequency selection unit and operates the device with the generated operation clock;
A wireless communication apparatus comprising: Comprising reference clock supply means for supplying a reference clock;
The timing control unit multiplies and divides the reference clock supplied from the reference clock supply unit, and further multiplies and divides the reference clock multiplied and divided in the device to generate the operation clock. The wireless communication device according to claim 1 to be generated.   The timing control means generates the operation clock by further multiplying and dividing the multiplied and divided reference clock in the camera module as the device, and operates the camera module with the generated operation clock. Item 3. A wireless communication device according to Item 2. Comprising reference clock supply means for supplying a reference clock;
The wireless communication apparatus according to claim 1, wherein the timing control unit generates the operation clock by multiplying and dividing the reference clock supplied from the reference clock supply unit.   The wireless communication apparatus according to claim 4, wherein the timing control unit operates a liquid crystal display device as the device with the generated operation clock.   The wireless communication apparatus according to claim 4, wherein the timing control unit operates a memory card device that is a device that reads data stored in a memory card or writes data to the memory card with the generated operation clock.   The frequency selection means operates for each frequency of the reception channel information based on a distance on a frequency axis between a frequency of the reception channel information and a candidate frequency that is a frequency of a harmonic signal component of the selectable operating frequency. The wireless communication apparatus according to claim 1, wherein the operating frequency is selected by weighting a frequency.   The radio communication apparatus according to claim 7, wherein the frequency selection unit obtains the weighted addition value for each operation frequency and selects the operation frequency having the largest addition value.   The radio according to claim 7 or 8, wherein the frequency selection means sets the weighting to be different when the distance is within a predetermined band from the frequency of the reception channel information and when the distance is outside the band. Communication device.   The radio communication apparatus according to claim 9, wherein the frequency selection unit sets the weighting to be different between a case where data is spread in a frequency axis direction and a case where the data is outside the band.   The frequency selection means multiplies the weighting of the candidate frequencies not interfering with the frequency of the reception channel information used in the currently communicating cell by multiplying by a predetermined coefficient for preferential selection. The wireless communication apparatus according to claim 8, wherein an operating frequency is selected.   The frequency selection means sets the weight of the operating frequency that interferes with the frequency of the reception channel information to “0”, sets the weight of the operating frequency that does not interfere with the frequency of the reception channel information to “1”, The wireless communication apparatus according to claim 11, wherein the coefficient is multiplied by “3”.   In the case where two or more operating frequencies that do not interfere with the radio frequency can be selected, the frequency selecting means is currently communicating within the frequency of the harmonic signal components of the two or more selectable operating frequencies. The radio communication apparatus according to any one of claims 1 to 12, wherein the operation frequency that generates a harmonic signal component having a frequency farthest from a radio frequency of a cell that is located is selected.   A frequency selection method for selecting an operating frequency that does not interfere with the radio frequency based on reception channel information that is information on a radio frequency used in each cell.   The operating frequency is weighted for each frequency of the reception channel information based on a distance on a frequency axis between a frequency of the reception channel information and a candidate frequency that is a frequency of a harmonic signal component of the selectable operating frequency. The frequency selection method according to claim 14, wherein an operating frequency is selected.   The frequency selection method according to claim 15, wherein an addition value of the weights for each operation frequency is obtained, and the operation frequency having the largest addition value is selected.   The frequency selection method according to claim 15 or 16, wherein the weighting is different between a case where the distance is within a predetermined band from a frequency of the reception channel information and a case where the distance is outside the band.   The frequency selection method according to claim 17, wherein the weighting is different between a case where the operating frequency is included in the band in which data is spread in a frequency axis direction and a case where the operating frequency is not included in the band.   The operating frequency is selected by multiplying a predetermined coefficient for preferentially selecting the weighting of the operating frequency that does not interfere with the frequency of the reception channel information used in a cell currently being communicated. The frequency selection method according to any one of claims 16 to 18.   The weight of the operating frequency that interferes with the frequency of the reception channel information is set to “0”, the weight of the operating frequency that does not interfere with the frequency of the reception channel information is set to “1”, and the coefficient is “3”. The frequency selection method according to claim 19, wherein:   When it is possible to select two or more operating frequencies that do not interfere with the radio frequency, from the radio frequency of the cell that is currently communicating among the harmonic signal component frequencies of the two or more selectable operating frequencies. The frequency selection method according to any one of claims 15 to 20, wherein the operating frequency that generates a harmonic signal component having the farthest frequency is selected.

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