JP2004357325A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate an unnecessary wave component outside the desired band of a radio signal. <P>SOLUTION: Frequency converting parts 104a to 104n multiply a modulated transmission signal by a local signal to convert the frequency of the transmission signal into an intermediate frequency. Filter parts 105a to 105n attenuate a frequency region other than a desired signal region for the transmission signal after frequency conversion. Further, E/O parts 106a to 106n convert the transmission signal from an electric signal into an optical signal and output the optical signal to O/E parts 151a to 151n of a base station device 150. The O/E parts 151a to 151n convert the optical signal into an electric signal, and the filter parts 152a to 152n attenuate a frequency region other than the desired signal region for the transmission signal that has been converted into the electric signal. Frequency converting parts 154a to 154n multiply the transmission signal by the local signal to convert the frequency of the transmission signal into a radio frequency, and output the transmission signal after the frequency conversion to amplifier parts 155a to 155n. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system including a control station device and a base station device that perform optical transmission.

  2. Description of the Related Art Conventionally, when a wireless base station device is installed at a position distant from an antenna, the antenna may be connected to the wireless base station using a coaxial cable or the like. In this case, a power loss occurs during transmission of the signal via the coaxial cable. In particular, the larger the power of the signal, the greater the power loss, and the wireless base station apparatus has a problem that the power consumption is increased in order to obtain a signal output in consideration of the power loss.

  Therefore, a transmission path from the radio base station apparatus to the antenna is an optical fiber, a circuit for converting a signal to be transmitted from an electric signal to an optical signal, and a signal for converting an optical signal to an electric signal near the antenna is provided. By providing the antenna in the vicinity of the antenna, power loss during transmission of a signal from the wireless base station device to the antenna and increase in power consumption of the wireless base station device can be suppressed.

  However, the conventional apparatus has a problem in that after transmitting using an optical signal, an optical signal is converted into an electric signal and an unnecessary frequency region signal is amplified when power amplification is performed.

  The present invention has been made in view of the above, and an object of the present invention is to provide a communication system capable of removing unnecessary wave components outside a desired band of a wireless signal.

  In order to solve such a problem, a communication system according to the present invention includes an intermediate frequency conversion unit that converts a frequency of a transmission signal to an intermediate frequency, and a base station that converts the transmission signal converted to the intermediate frequency from an electric signal to an optical signal. Light-to-light conversion means for transmitting to a station device, and a control station device comprising a transmission power value output means for outputting a transmission power value indicating the power of a transmission signal transmitted wirelessly in the base station device to the base station device, A photoelectric conversion unit that converts transmission signals of a plurality of carriers transmitted as optical signals from the control station device to optical signals of an intermediate frequency from optical signals, and includes other carriers of the own device from the transmission signals converted to electrical signals. Filter means for attenuating unwanted waves, and a frequency of a transmission signal from which a signal other than a desired signal has been removed by the filter means is higher than an intermediate frequency for each carrier. Take a radio frequency converting means for converting to a radio frequency, the arrangement comprising a amplifying means for amplifying a transmission signal converted into the radio frequency according to the output transmission power value from the control station apparatus.

  According to the present invention, a transmission signal is converted into an intermediate frequency, then converted into an optical signal, and optically transmitted. After converting the optical signal into an electric signal, a process for removing signals other than signals in a desired frequency region is performed. By converting the signal to a radio frequency signal later, unnecessary wave components outside the desired band of the radio signal can be removed.

  The inventor of the present invention has found that the frequency of a signal to be transmitted optically is transmitted as a signal having a frequency at which an unnecessary wave component outside a desired band can be easily removed from a radio frequency, and has accomplished the present invention.

  That is, the gist of the present invention is to convert a transmission signal to an intermediate frequency, convert the transmission signal to an optical signal, optically transmit the optical signal, convert the optical signal to an electric signal, and remove a signal other than a signal in a desired frequency region. And then converting it to a radio frequency signal.

  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 configurations of a control station device and a base station device according to Embodiment 1 of the present invention. The control station device 100 in FIG. 1 includes n encoding units (COD) 101a to 101n, n modulation units (MOD) 102a to 102n, a local oscillation unit (OSC) 103, and n frequency conversion units. (F-CONV) units 104a to 104n, n filter units (FLT) 105a to 105n, n E / O units (E / O) 106a to 106n, a transmission power control unit (PWC) 111, , E / O unit (E / O) 112, n O / E units (O / E) 121a to 121n, n filter units (FLT) 122a to 122n, and local transmission unit (OSC) 123 , N frequency conversion units (f-CONV) 124a to 124n, n demodulation units (DEMOD) 125a to 125n, and n decoding units (DECOD) 126a to 126n. .

  The base station apparatus 150 includes n O / E units (O / E) 151a to 151n, n filter units (FLT) 152a to 152n, a local transmission unit (OSC) 153, and n Frequency converters (f-CONV) 154a to 154n, n amplifiers (AMP) 155a to 155n, n duplexers (COM) 156a to 156n, n antennas 157a to 157n, and O / E section (O / E) 161, transmission power control section (PWC) 162, n amplifying sections (AMP) 171a to 171n, local oscillator section (OSC) 172, and n frequency converting sections (f -CONV) 173a to 173n, n filter units (FLT) 174a to 174n, and n E / O units (E / O) 175a to 175n.

  First, a part for transmitting a transmission signal from control station apparatus 100 to base station apparatus 150 will be described. In FIG. 1, encoding sections 101a to 101n encode transmission signals and output the encoded signals to modulation sections 102a to 102n, respectively. Modulating sections 102a to 102n modulate the encoded transmission signals and output the modulated signals to frequency converting sections 104a to 104n, respectively.

  Local oscillator 103 generates an intermediate frequency local signal and outputs the signal to frequency converters 104a to 104n. Frequency converters 104a to 104n multiply the modulated transmission signal by a local signal to convert the frequency of the transmission signal to an intermediate frequency, and output the frequency-converted transmission signal to filter units 105a to 105n, respectively.

  Filter sections 105a to 105n attenuate a frequency region other than a desired signal region with respect to the transmission signal after frequency conversion, and output the resulting signal to E / O sections 106a to 106n. E / O sections 106a to 106n convert the transmission signals output from filter sections 105a to 105n from electrical signals to optical signals and output the signals to O / E sections 151a to 151n of base station apparatus 150.

  Transmission power control section 111 outputs a control information signal including transmission power information of each transmission signal to E / O section 112. E / O section 112 converts the control information signal from an electric signal to an optical signal and outputs the signal to O / E section 161 of base station apparatus 150.

  The O / E units 151a to 151n convert the optical signals output from the E / O units 106a to 106n into electric signals, and output the obtained transmission signals to the filter units 152a to 152n. The filter units 152a to 152n attenuate a frequency region other than a desired signal region with respect to the transmission signal converted into the electric signal and output the signal to the frequency conversion units 154a to 154n.

  Local oscillator 153 generates a local signal having a frequency equal to the difference between the radio frequency and the intermediate frequency, and outputs the signal to frequency converters 154a to 154n. The frequency conversion units 154a to 154n multiply the transmission signals output from the filter units 152a to 152n by a local signal to convert the frequency of the transmission signal to a radio frequency, and amplify the transmission signals after frequency conversion to the amplification units 155a to 155n, respectively. Output to

  Amplifying sections 155a to 155n amplify the transmission signal converted to the radio frequency to a transmission power value instructed by transmission power control section 162, and output it to duplexers 156a to 156n. The duplexers 156a to 156n output the transmission signals output from the amplifiers 155a to 155n to the antennas 157a to 157n. The antennas 157a to 157n transmit the transmission signals output from the duplexers 156a to 156n as radio signals.

  The O / E section 161 converts the control information signal output from the E / O section 112 from an optical signal to an electric signal, and outputs the signal to the transmission power control section 162. Transmission power control section 162 outputs the transmission power value of each transmission signal to amplification sections 155a to 155n according to the control information signal.

  Next, operations of the control station device and the base station device according to the present embodiment will be described. First, an operation of transmitting a transmission signal from control station apparatus 100 to base station apparatus 150 will be described.

  On the control station apparatus 100 side, the transmission signal is encoded in encoding sections 101a to 101n, modulated in modulation sections 102a to 102n, frequency-converted to an intermediate frequency in frequency conversion sections 104a to 104n, and filtered in 105a to 105n. , A frequency region other than the desired signal region is attenuated, and the E / O units 106 a to 106 n convert the electric signal into an optical signal and output the converted signal to the base station device 150.

  Then, on the base station apparatus 150 side, the transmission signal is converted from an optical signal to an electric signal in the O / E sections 151a to 151n. Various noises are added to the transmission signal converted into the electric signal.

  For example, noise includes noise generated on a light emitting element such as an LD (Laser Diode) or the like and an optical transmission path, shot noise generated in a light receiving element that receives an optical signal in the O / E sections 151a to 151n, O / O There is a thermal noise or the like generated in an amplifier (for example, a preamplifier) of a signal converted into an electric signal in the E units 151a to 151n.

  When a transmission signal containing these noises is converted to a radio frequency and transmitted as a radio signal, a leaked radio signal is generated in a frequency region outside a desired frequency region.

  For example, in the 3GPP (3rd Generation Partnership Project) that formulates the IMT-2000 standard, the standard modulation bandwidth of a signal to be transmitted is 3.84 MHz, and an unnecessary wave centered on a frequency 5 MHz away from the intermediate frequency of the transmission signal. Stipulates that the signal level of the transmitted signal is 45 dB or less than the level of the transmitted signal, and that the signal level of the unnecessary wave centered on the frequency 10 MHz away from the intermediate frequency of the transmitted signal is 50 dB or less than the level of the transmitted signal. are doing. However, the signal to be transmitted may not satisfy the regulation due to the noise or the like.

  Therefore, the transmission signal is converted to an intermediate frequency, and unnecessary frequency components are removed at the intermediate frequency. FIG. 2 is a diagram illustrating an example of a frequency distribution of power of a transmission signal. In FIG. 2, noise components 202 and 203 exist in a region away from the center frequency f of the desired signal 201. The communication device sufficiently attenuates unnecessary frequency components using a filter.

  Here, when a filter that attenuates a frequency region other than a desired signal region in a radio frequency is used, the filter is required to have a characteristic of attenuating a predetermined amount with respect to a signal in a frequency region apart from the center frequency. FIG. 3 is a diagram illustrating an example of an attenuation characteristic of a filter used in a radio frequency and a frequency distribution of power of a transmission signal. In FIG. 3, a distribution 301 is a frequency distribution of power of the transmission signal obtained by removing a noise component from the transmission signal shown in FIG. 2 using a filter having an attenuation characteristic 302.

  As shown in FIG. 2, the attenuation characteristic 302 of the filter does not have sufficient attenuation in a frequency region away from the center frequency. The noise components 303 and 304 are distributions of the noise components 202 and 203 of FIG. 2 which are attenuated by the filter.

  Therefore, the frequency of the transmission signal is once converted to an intermediate frequency, and a filter is applied to the transmission signal of the intermediate frequency to remove noise components. This intermediate frequency can be set to a lower frequency than the radio frequency. Then, the filter at the intermediate frequency can increase the ratio between the frequency in the pass band and the center frequency of the target signal as compared with the filter at the radio frequency, and can sufficiently separate and remove unnecessary waves. FIG. 4 is a diagram illustrating an example of an attenuation characteristic of a filter and a frequency distribution of power of a transmission signal. The filter in FIG. 4 is a filter for an intermediate frequency. In FIG. 4, the filter attenuation characteristic 401 can have a steep attenuation characteristic from a region separated by a predetermined frequency from the intermediate frequency f. Then, the noise components 403 and 404 can be sufficiently attenuated without attenuating the signal 402.

  As described above, by using the filter that attenuates the frequency region other than the desired signal region, it is possible to attenuate unnecessary waves including other carriers of the own device. 5 and 6 are diagrams illustrating an example of the frequency distribution of the power of the transmission signals of a plurality of carriers. FIG. 5 shows an example in which the signal after passing through the filter having the characteristics shown in FIG. 3 is arranged on a plurality of carriers at a radio frequency. The signals 451, 452, and 453 have high signal levels even in frequency regions other than the desired signal regions 456, 457, and 458, and the signals affect each other as noise, and the signal-to-noise ratio deteriorates.

  FIG. 6 shows an example in which the signal after passing through the filter having the characteristics shown in FIG. 4 is allocated to a plurality of carriers at a radio frequency. The signals 461, 462, and 463 have low signal levels in frequency regions other than the desired signal regions 466, 467, and 468, and the signals have little influence as noise and a good signal-to-noise ratio.

  As described above, the control station device 100 and the base station device 150 use the filters that attenuate unnecessary waves including other carriers of the own device.

  As described above, the transmission signal is converted into a radio frequency by the frequency conversion units 154a to 154n after the noise components are removed by the filter units 152a to 152n. Then, the signal levels (for example, the transmission power values) are amplified in the amplification units 155a to 155n.

  On the other hand, optical transmission has a feature that the dynamic range is narrower than transmission by electric signals. In optical transmission, the upper limit of the dynamic range is low, and the signal level of a signal having a high signal level is saturated, and the strength of an electric signal may not be sufficiently expressed. Conversely, if the upper limit of the dynamic range and the upper limit of the signal level are matched, a weak signal may be buried in noise.

  Therefore, the transmission power control section 111 of the control station apparatus 100 outputs information on the transmission power of each transmission signal to the transmission power control section 162 of the base station apparatus 150, and instructs the amplification sections 155a to 155n on the transmission power value to be amplified. . Then, when amplifying the transmission signal after converting the optical signal into the electric signal in base station apparatus 150, by determining the amount of amplification based on the transmission power value output from transmission power control section 162, the optical transmission The characteristic with a narrow dynamic range can be compensated. Then, the transmission signal is transmitted as a radio signal via the antennas 157a to 157n.

  As described above, according to the control station device and the base station device of the present embodiment, in the control station device, after converting the frequency of the transmission signal to the intermediate frequency, the transmission signal is electro-optically converted and transmitted to the base station device, In the base station device, the transmission signal is photoelectrically converted, and after the unnecessary signal other than the desired area is attenuated using a filter for the transmission signal of the intermediate frequency after the photoelectric conversion, the transmission signal is frequency-converted to the radio frequency. A filter having good noise removal characteristics can be used, and unnecessary wave components outside the desired band of the radio signal can be removed.

  Next, a portion for transmitting a received signal from base station apparatus 150 to control station apparatus 100 will be described.

  In FIG. 1, antennas 157a to 157n receive radio signals and output the received signals to duplexers 156a to 156n. Duplexers 156a to 156n output the received signals output from antennas 157a to 157n to amplification units 171a to 171n. Amplifying sections 171a to 171n amplify the received signals output from duplexers 156a to 156n and output the amplified signals to frequency conversion sections 173a to 173n.

  Local transmission section 172 generates a local signal having a frequency equal to the difference between the radio frequency and the intermediate frequency, and outputs the generated local signal to frequency conversion sections 173a to 173n. The frequency converters 173a to 173n multiply the received signals output from the amplifiers 171a to 171n by a local signal to convert the frequency of the received signal into an intermediate frequency, and convert the frequency-converted received signals into filter units 174a to 174n, respectively. Output to

  Filter sections 174a to 174n attenuate frequency regions other than the desired signal region with respect to the frequency-converted received signal and output the signals to E / O sections 175a to 175n. The E / O units 175a to 175n convert the transmission signals output from the filter units 174a to 174n from electrical signals to optical signals and output the signals to the O / E units 121a to 121n of the control station device 100.

  The O / E units 121a to 121n convert the optical signals output from the E / O units 175a to 175n into electric signals, and output the obtained transmission signals to the filter units 122a to 122n. The filter units 122a to 122n attenuate a frequency region other than a desired signal region with respect to the transmission signal converted into the electric signal and output the signal to the frequency conversion units 124a to 124n.

  Local transmission section 123 generates a local signal of an intermediate frequency and outputs it to frequency conversion sections 124a to 124n. The frequency conversion units 124a to 124n multiply the reception signals output from the filter units 122a to 122n by local signals, convert the reception signals into frequencies that can be demodulated by the demodulation units 125a to 125n, and output the converted signals to the demodulation units 125a to 125n. I do.

  Demodulation sections 125a to 125n demodulate the received signals output from frequency conversion sections 124a to 124n and output the signals to decoding sections 126a to 126n. The decoding units 126a to 126n decode the received signals output from the demodulation units 125a to 125n.

  When transmitting a reception signal from base station apparatus 150 to control station apparatus 100, filters of intermediate frequencies can be used in filter sections 122a to 122n. As in the case where the transmission signal is transmitted from the control station apparatus 100 to the base station apparatus 150, the transmission signal from which the noise component has been removed by using the filter at the intermediate frequency is smaller than that in the case where the filter is used at the radio frequency. The ratio between the frequency and the center frequency of the target signal can be increased, and unnecessary waves can be sufficiently separated and removed.

  As described above, according to the control station apparatus and the base station apparatus of the present embodiment, the base station apparatus converts the frequency of the radio frequency reception signal to the intermediate frequency, and then performs light-to-light conversion on the reception signal to perform control station apparatus conversion. Then, in the control station device, the received signal is photoelectrically converted, the filter is used to attenuate unnecessary signals outside the desired area using a filter on the received signal of the intermediate frequency after the photoelectric conversion, and then the received signal is converted into a baseband signal. By performing the conversion, unnecessary wave components outside the desired band of the wireless signal can be removed using a filter having good noise removal characteristics, and a good received signal can be obtained.

(Embodiment 2)
FIG. 7 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 2 of the present invention. However, components having the same configuration as in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and detailed description is omitted.

  7 includes a multiplexing unit (DUP) 501, an E / O unit (E / O) 502, an O / E unit (O / E) 503, and a demultiplexing unit (SEP) 504. Then, after dividing and multiplexing the transmission signal converted to the intermediate frequency in units of frequency, light-to-light conversion and transmission to the base station apparatus 550, and after photoelectrically converting the optical signal transmitted from the base station apparatus 550, The difference from the control station apparatus of FIG. 1 is that the frequency multiplexed signal is separated at the intermediate frequency.

  7 includes an O / E unit (O / E) 551, a demultiplexing unit (SEP) 552, a multiplexing unit (DUP) 553, and an E / O unit (E / O) 554. After the photoelectric conversion of the optical signal transmitted from the control station device 500, the frequency-multiplexed signal is separated at the intermediate frequency, and the received signal converted to the intermediate frequency is divided and multiplexed in frequency units. 1 is different from the base station apparatus of FIG.

  Filter sections 105a to 105n attenuate a frequency region other than a desired signal region with respect to the frequency-converted transmission signal and output the result to multiplexing section 501.

  The multiplexing section 501 multiplexes the intermediate frequency transmission signals output from the filter sections 105a to 105n for each frequency, and outputs the multiplexed transmission signal to the E / O section 502. E / O section 502 converts the transmission signal output from multiplexing section 501 from an electrical signal to an optical signal and outputs the converted signal to O / E section 551 of base station apparatus 550.

  The O / E section 551 converts the optical signal output from the E / O section 502 into an electric signal, and outputs the obtained transmission signal to the separation section 552. Separating section 552 separates and extracts the transmission signal after conversion into an electric signal in units of a predetermined frequency region, and outputs the extracted transmission signal to filter sections 152a to 152n.

  Filter sections 152a to 152n attenuate the frequency domain other than the desired signal area with respect to the transmission signal separated by frequency section in separation section 552, and output the resulting signal to frequency conversion sections 154a to 154n.

  As described above, according to the control station device and the base station device of the present embodiment, in the control station device, the frequency of the transmission signal is converted to the intermediate frequency, and an unnecessary signal other than the desired region is attenuated using the filter. After that, the transmission signal converted to the intermediate frequency is divided and multiplexed in the frequency domain, then converted to an optical signal and transmitted to the base station device, and the base station device converts the optical signal to an electric signal, After separation in units of regions, frequency conversion to radio frequency can reduce the number of optical fibers required for optical transmission.

  Next, a portion for transmitting a received signal from base station apparatus 550 to control station apparatus 500 will be described.

  In FIG. 7, filter sections 174 a to 174 n attenuate a frequency area other than a desired signal area with respect to the received signal after frequency conversion and output the result to multiplexing section 553. The multiplexing unit 553 multiplexes the intermediate frequency reception signals output from the filter units 174a to 174n for each frequency, and outputs the multiplexed signals to the E / O unit 554. E / O section 554 converts the received signal output from multiplexing section 553 from an electric signal to an optical signal and outputs the converted signal to O / E section 503 of control station apparatus 500.

  The O / E section 503 converts the optical signal output from the E / O section 554 into an electric signal, and outputs the obtained reception signal to the separation section 504. Separating section 504 separates and extracts the received signal after conversion into an electric signal in units of a predetermined frequency region, and outputs the extracted transmission signal to filter sections 122a to 122n.

  The filter units 122a to 122n attenuate a frequency region other than a desired signal region with respect to the transmission signal converted into the electric signal and output the signal to the frequency conversion units 124a to 124n.

  Next, the setting of the intermediate frequency will be described. FIG. 8 is a diagram illustrating an example of a frequency distribution of a signal transmitted between the control station device and the base station device according to the present embodiment. 8, the vertical axis indicates the signal level, and the horizontal axis indicates the frequency.

  Local oscillator 103 outputs local signals of different frequencies to frequency converters 104a to 104n. The frequency converters 104a to 104n combine the local signal output from the local oscillator 103 and the transmission signal, and convert the transmission signal into different intermediate frequencies. Here, the intermediate frequency of the transmission signal is set for each integral multiple of the reference signal frequency. For example, if the reference signal frequency is Δfs, the transmission signal is set for each Δf obtained by multiplying Δfs by an integer.

  By converting the signal to the intermediate frequency shown in the above description and multiplexing the signal, it is possible to reduce the effects of third-order distortion and CTB on signals of other frequencies.

  As described above, according to the control station device and the base station device of the present embodiment, in the base station device, the frequency of the received signal is converted into the intermediate frequency, and an unnecessary signal other than the desired region is attenuated using the filter. After that, the received signal converted to the intermediate frequency is divided and multiplexed in the frequency domain, converted to an optical signal and transmitted to the control station device, and the control station device converts the optical signal to an electric signal, After separation in units of regions, frequency conversion to radio frequency can reduce the number of optical fibers required for optical transmission.

(Embodiment 3)
FIG. 9 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 3 of the present invention. However, components having the same configuration as in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and detailed description is omitted.

  The control station device 600 of FIG. 9 includes a multiplexing unit (DUP) 601 and a demultiplexing unit (SEP) 602. The difference from the control station apparatus of FIG. 1 is that the signal is transmitted to the station apparatus 650 and that the optical signal transmitted from the base station apparatus 650 is separated by wavelength and then electro-optically converted.

  Further, the base station apparatus in FIG. 9 includes a demultiplexing unit (SEP) 651 and a multiplexing unit (DUP) 652, and separates an optical signal transmitted from the control station apparatus 600 in units of wavelengths and then performs electro-optical conversion. 1 is different from the base station apparatus of FIG. 1 in that the received signal converted to the intermediate frequency is electro-optically converted, divided by wavelength unit, multiplexed, and transmitted to the control station apparatus 600.

  The E / O units 106a to 106n convert the transmission signals output from the filter units 105a to 105n from electric signals to optical signals and output the signals to the multiplexing unit 601. Multiplexing section 601 wavelength-multiplexes the transmission signal converted into the optical signal and outputs the result to demultiplexing section 651 of base station apparatus 650.

  Demultiplexing section 651 demultiplexes the transmission signal output from multiplexing section 601 in wavelength units before being multiplexed in control station apparatus 600, and outputs the separated transmission signals to O / E sections 151a to 151n, respectively. The O / E sections 151a to 151n convert the optical signal output from the separation section 651 into an electric signal, and output the obtained transmission signal to the filter sections 152a to 152n.

  Similarly, base station apparatus 650 performs light-to-light conversion on the received signal converted to the intermediate frequency, and then wavelength-multiplexes the signal to output to control station apparatus 600.

  The E / O units 175a to 175n convert the transmission signals output from the filter units 174a to 174n from electric signals to optical signals and output the converted signals to the multiplexing unit 652. Multiplexing section 652 wavelength-multiplexes the transmission signal converted into the optical signal and outputs the result to demultiplexing section 602 of control station apparatus 600.

  In control station apparatus 600, demultiplexing section 602 separates the received signal output from multiplexing section 652 in wavelength units before being multiplexed in base station apparatus 650, and separates the received signal into O / E sections 121a to 121n. Output each. The O / E units 121a to 121n convert the optical signals output from the separation unit 602 into electric signals, and output the obtained transmission signals to the filter units 122a to 122n.

  As described above, according to the control station apparatus and the base station apparatus of the present embodiment, the control station apparatus converts a transmission signal into an intermediate frequency, wavelength-multiplexes a plurality of electro-optically converted transmission signals, and transmits the signal to the base station apparatus. In the base station device, the number of optical fibers required for optical transmission can be reduced by performing photoelectric conversion and wavelength conversion to radio frequency after separation in wavelength units.

(Embodiment 4)
FIG. 10 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 4 of the present invention. However, components having the same configuration as in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and detailed description is omitted.

  The control station device 700 of FIG. 10 includes a directivity control unit (BMC) 701 and phase control units (PHC) 702a to 702n, and transmits one signal with a phase difference from a plurality of antennas and transmits the signal. The difference from the control station apparatus of FIG.

  The directivity control unit 701 receives directivity instruction information generated when a transmission signal is transmitted, and instructs the phase control units 702a to 702n of the phase of the signal transmitted from the antennas 157a to 157n based on this instruction.

  The phase control units 702a to 702n add a phase difference to the transmission signal according to the instruction from the directivity control unit 701 and output the transmission signal to the encoding units 101a to 101n. For example, the phase control units 702a to 702n delay transmission signals to provide a phase difference.

  Transmission signals are encoded by 101a to 101n, modulation units 102a to 102n, frequency conversion units 104a to 104n, filter units 105a to 105n, E / O units 106a to 106n, O / E units 151a to 151n, and filter units 152a to 152n. 152n, frequency converters 154a to 154n, amplifiers 155a to 155n, and duplexers 156a to 156n, and are transmitted from antennas 157a to 157n.

  As described above, according to the control station apparatus and the base station apparatus of the present embodiment, the control station apparatus transmits a signal by forming a directivity by transmitting a transmission signal with a phase difference from a plurality of antennas. Can be.

  In the present embodiment, each transmission signal is transmitted from the control station device to the base station device using a different optical fiber. However, as in the case of the second or third embodiment, even if the signals are multiplexed and transmitted. Good.

  In this case, the control station apparatus and the base station apparatus according to the present embodiment can reduce the number of optical fibers required for optical transmission, and can transmit signals by transmitting transmission signals using the same optical fibers. Generation (skew) of a phase difference due to a difference in a path can be suppressed.

  Further, the transmission signal may be provided with a phase difference, and the arrangement of the phase control unit for performing the process of providing the phase difference is not particularly limited. The arrangement of the phase control unit that performs the process of providing a phase difference may be on the base station apparatus side. Further, a phase difference can be provided in a portion transmitting an optical signal. In this case, a phase difference can be provided by making the length of the optical fiber different for each transmission line.

(Embodiment 5)
FIG. 11 is a block diagram showing configurations of a control station device and a base station device according to Embodiment 5 of the present invention. However, components having the same configuration as in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and detailed description is omitted.

  When transmitting transmission signals of a plurality of intermediate frequencies on the same optical transmission line, a signal from which unnecessary wave components have been removed is multiplexed and transmitted to each intermediate frequency rice. If the number of carriers used in optical transmission is less than the maximum number of carriers that can be transmitted, unnecessary waves such as noise and distortion may be output from a filter corresponding to a transmission path that does not transmit a signal.

  For example, at the present time, in W-CDMA, services may be provided by only two carriers out of a band of four carriers due to the required amount of traffic and the like, and unnecessary wave components such as noise and distortion may be transmitted from a filter of a carrier not used for transmission. May be output and the specifications such as the Radio Law may not be complied with.

  The base station device 850 of FIG. 11 includes signal detection units (DET) 801a to 801n and signal cutoff units (SW) 802a to 802n, and cuts off the output of a filter on a transmission line that does not transmit a signal. 1 in that unnecessary wave components of noise, distortion, and distortion are prevented from being output.

  In FIG. 11, filter sections 152a to 152n attenuate a frequency region other than a desired signal region with respect to a transmission signal converted into an electric signal and output the signal to signal detection sections 801a to 801n and signal cutoff sections 802a to 802n. . The signal detection units 801a to 801n determine whether or not the transmission signals are output from the filter units 152a to 152n, and output the signal detection results to the signal blocking units 802a to 802n.

  When signals are detected from the results output from the signal detection units 801a to 801n, the signal blocking units 802a to 802n output the transmission signals output from the filter units 152a to 152n to the frequency conversion units 154a to 154n. If no signal is detected from the results output from the signal detection units 801a to 801n, the signal blocking units 802a to 802n output the transmission signals output from the filter units 152a to 152n to the frequency conversion units 154a to 154n. do not do.

  The frequency conversion units 154a to 154n multiply the transmission signals output from the filter units 152a to 152n by a local signal to convert the frequency of the transmission signal to a radio frequency, and amplify the transmission signals after frequency conversion to the amplification units 155a to 155n, respectively. Output to

  As described above, according to the base station apparatus of the present embodiment, the output of the filter on the transmission line that is not transmitting a signal is cut off to prevent unnecessary wave components of noise and distortion from being output, thereby enabling wireless communication. An increase in unnecessary wave components outside the desired band for the signal can be prevented.

  Note that the signal transmission device of the present invention has an unnecessary wave component using a filter immediately before converting a transmission signal to a radio frequency, but it suffices to remove a signal other than a desired signal using a filter on a signal of an intermediate frequency. The arrangement of the filters is not particularly limited as long as the arrangement processes the signal of the intermediate frequency.

  Further, the output of the radio frequency is not particularly limited, and is not limited to outputting each transmission signal from a different antenna. The transmission signal of a plurality of radio frequencies can be multiplexed and output from one antenna. For example, the transmission signal may be multiplexed at a radio frequency, or may be multiplexed at an intermediate frequency and then converted to a radio frequency.

  Further, in the conversion of the intermediate frequency, the influence of the multiple reflection distortion of the local signal and the noise can be reduced by combining the transmission signal and the local signal with the frequency of the local signal being higher than the intermediate frequency.

  As is apparent from the above description, according to the present invention, the transmission signal is converted to an intermediate frequency, then converted to an optical signal and optically transmitted, and after converting this optical signal to an electric signal, By converting the signal to a radio frequency signal after performing processing for removing signals other than the signal, it is possible to remove unnecessary wave components outside the desired band of the radio signal.

  INDUSTRIAL APPLICABILITY The present invention is suitable for use in a communication system including a base station device and a control station device using a CDMA communication system.

FIG. 2 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 1 of the present invention. Diagram showing an example of frequency distribution of power of a transmission signal FIG. 4 is a diagram illustrating an example of an attenuation characteristic of a filter used in a radio frequency and a frequency distribution of power of a transmission signal. Diagram showing an example of the attenuation characteristics of the filter and the frequency distribution of the power of the transmission signal The figure which shows an example of the frequency distribution of the electric power of the transmission signal of several carriers. The figure which shows an example of the frequency distribution of the electric power of the transmission signal of several carriers. FIG. 4 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 2 of the present invention. The figure which shows an example of the frequency distribution of the signal transmitted between the control station apparatus and base station apparatus of the said embodiment. FIG. 9 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 3 of the present invention. FIG. 9 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 4 of the present invention. FIG. 17 is a block diagram showing a configuration of a control station apparatus and a base station apparatus according to Embodiment 5 of the present invention.

Claims (1)

Intermediate frequency conversion means for converting the frequency of the transmission signal to an intermediate frequency, electro-optical conversion means for converting the transmission signal converted to the intermediate frequency from an electric signal to an optical signal and transmitting the signal to a base station device, and the base station device A control station apparatus comprising: a transmission power value output unit that outputs a transmission power value indicating the power of a transmission signal transmitted wirelessly to the base station apparatus,
A photoelectric conversion unit that converts transmission signals of a plurality of carriers transmitted as optical signals from the control station device to optical signals of an intermediate frequency from optical signals, and includes other carriers of the own device from the transmission signals converted to electrical signals. Filter means for attenuating unnecessary waves, radio frequency conversion means for converting the frequency of the transmission signal from which a signal other than a desired signal has been removed by the filter means to a radio frequency higher than an intermediate frequency for each carrier, and the control station A communication system comprising: a base station device including: amplifying means for amplifying a transmission signal converted into a radio frequency according to a transmission power value output from the device.

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