JP2011124650A - Relay device, and relay method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute automatic gain control suitable for a signal corresponding to each system even when a plurality of systems share a frequency band. <P>SOLUTION: In this relay device 100 for amplifying a reception signal including a first signal and a second signal to be relayed and transmitted, an LPF 111-1 and an LPF 111-2 divide reception signals input from second frequency conversion parts 110-1 and 110-2 into first signals and second signals; and a gain control part 108 respectively individually controls amplification gain of the first signal and that of the second signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a relay apparatus and a relay method.

  The relay device is also referred to as a repeater or a booster, and is a signal transmitted from a transmission side (for example, a base station device) in order to make the radio wave dead zone area a wireless communication possible area (sometimes referred to as a cover area). Is a device that receives and amplifies and transmits the signal to the receiving side (for example, a terminal device). When amplifying a signal, a propagation loss (path loss) value between the base station apparatus and the relay apparatus is calculated, and amplification gain control is performed to compensate for the calculated propagation path loss value (hereinafter referred to as “automatic gain control”). There is a relay device that performs.

In general, the basic equation for automatic gain control of the relay device is that the gain of the relay device is G, the propagation loss value between the base station and the relay device is PathLoss, and the fixed value preset in the system is α Then, it is shown by the following formula (1).
G = PathLoss-α (1)

  In addition, in a wireless communication system (hereinafter referred to as an LTE system) to which 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) is applied, not only a base station (hereinafter referred to as an LTE base station) compatible with the LTE system, Base stations (hereinafter referred to as 3G base stations) corresponding to generation mobile communication systems (hereinafter referred to as 3G systems) are also mixed. That is, in LTE, the LTE system and the 3G system share the frequency band to be used.

  In the LTE system, the frequency bandwidth allocated to the signal is variable (for example, 1.4 MHz to 20 MHz). For this reason, in all usable frequency bands, there is a possibility that the frequency bands assigned to signals corresponding to the LTE system and the 3G system are variable. Therefore, in the LTE system, the relay device needs to perform relay processing (automatic gain control or the like) of signals corresponding to each system according to the frequency band variably assigned to each system.

  For example, even when the frequency band assigned to a signal is variable, a conventional technique for extracting a signal by changing the reception frequency band (that is, the filter pass band) by controlling the frequency band of the signal has been proposed ( For example, see Patent Document 1). By using this conventional technique, the relay device can receive and amplify a specific signal (that is, relay) by changing the reception frequency band even when the frequency band of the signal transmitted from the base station is variable. Processing).

JP 2006-304136 A

  However, in the above prior art, the frequency band can be controlled only for a signal corresponding to one system (here, one of the LTE system and the 3G system). Therefore, as described above, when signals received by the relay device include signals respectively corresponding to the LTE system and the 3G system, in order to amplify each signal, the device to which the above-described conventional technology is applied is a system. It is necessary to provide the relay apparatus for several minutes (here, two). In this case, the circuit configuration of the relay device becomes large and the processing becomes complicated.

  Therefore, a single relay device has a full frequency band (a relay band to be relayed by the relay device) including a signal corresponding to the LTE system (hereinafter referred to as LTE signal) and a signal corresponding to the 3G system (hereinafter referred to as 3G signal). ) May be amplified. For example, the relay apparatus can amplify all signals assigned to all frequency bands, which are fixed bandwidths, by performing automatic gain control based on the LTE signal.

  However, if a signal is amplified over the entire frequency band including signals corresponding to a plurality of systems, the relay device may not be able to perform appropriate amplification processing on the signals corresponding to each system.

  For example, when the LTE base station and the 3G base station are installed at substantially the same position, and the transmission power of the 3G signal is larger than the transmission power of the LTE signal, or the distance between the 3G base station and the relay device is A case where the distance is shorter than the distance between the LTE base station and the relay apparatus will be described. That is, in any case, in the relay device, the reception power of the 3G signal is larger than the reception power of the LTE signal.

  In this case, when the received signal is demodulated in the relay device, the LTE signal (received power: small) may be interfered with by the 3G signal (received power: high), and the reception characteristics of the LTE signal may deteriorate. is there. If the reception characteristics of the received signal deteriorate, for example, the relay device may not be able to appropriately perform the automatic gain control of the signal because information necessary for automatic gain control included in the received signal cannot be extracted. is there.

  Further, when the relay apparatus performs automatic gain control based on the LTE signal, the LTE signal is appropriately amplified, but there is a possibility that the 3G signal having a reception power larger than the reception power of the LTE signal is excessively amplified. is there. Conversely, when the relay device performs automatic gain control based on the 3G signal, the 3G signal is appropriately amplified, but the LTE signal having a reception power smaller than the reception power of the 3G signal may not be sufficiently amplified. .

  Note that the same problem occurs when the relationship between the transmission power or the distance between the relay station described above is opposite between the LTE base station and the 3G base station.

  As described above, when automatic gain control is performed on all frequency bands shared by a plurality of systems, reception characteristics of a received signal may be deteriorated, or amplification gain of the received signal may not be appropriate. In this case, the relay apparatus cannot perform appropriate automatic gain control on the signal corresponding to each system.

  An object of the present invention is to provide a relay apparatus and a relay method capable of performing appropriate automatic gain control on a signal corresponding to each system even when a plurality of systems share a frequency band. .

  The relay device of the present invention is a relay device that amplifies a received signal including a first signal and a second signal and relays the received signal. The relay signal is transmitted to the first signal and the second signal. And a control means for individually controlling the amplification gain of the first signal and the amplification gain of the second signal.

  The relay method of the present invention is a relay method in a relay apparatus that amplifies and relays a received signal including a first signal and a second signal, and the transmission signal is transmitted between the first signal and the second signal. And a control step for individually controlling the amplification gain of the first signal and the amplification gain of the second signal.

  According to the present invention, even when a plurality of systems share a frequency band, appropriate automatic gain control can be performed on a signal corresponding to each system.

The block diagram which shows the structure of the relay apparatus which concerns on one embodiment of this invention The figure which shows the received signal in the relay apparatus which concerns on one embodiment of this invention The figure which shows the relay process which concerns on one embodiment of this invention The figure which shows the other received signal in the relay apparatus which concerns on one embodiment of this invention The figure which shows the other relay processing which concerns on one embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a case will be described in which the relay apparatus according to the embodiment of the present invention relays and transmits a signal transmitted from a base station (LTE base station and 3G base station) to a terminal.

  In the following description, an LTE signal from an LTE base station and a 3G signal from a 3G base station are allocated to a relay band that is a frequency band to be relayed by the relay device. That is, the LTE system and the 3G system share a frequency band. The relay apparatus according to the present embodiment amplifies a received signal including an LTE signal and a 3G signal, and a terminal apparatus (hereinafter referred to as LTE terminal) corresponding to the LTE system and a terminal (hereinafter referred to as 3G terminal) corresponding to the 3G system. To relay).

  FIG. 1 is a block diagram showing a configuration of a relay device according to the present embodiment. In the relay device 100 shown in FIG. 1, a local oscillator 109-1, a second frequency converter 110-1, an LPF (Low Pass Filter) 111-1, an amplifier 112-1, a switch 113-1, and a second frequency converter. 114-1 is provided as a processing system corresponding to one of the LTE system and the 3G system, and includes a local oscillator 109-2, a second frequency converter 110-2, an LPF 111-2, an amplifier 112-2, and a switch 113-. 2 and the second frequency conversion unit 114-2 are provided as a processing system corresponding to the other of the LTE system and the 3G system. That is, the relay apparatus 100 is provided with a processing system corresponding to each system. Further, in the relay device 100, cut-off frequencies are set in advance for the LPF 111-1 and the LPF 111-2.

  The first frequency converter 102 converts the frequency of a received signal (RF signal) received via the antenna 101 into an IF signal. Then, the first frequency converter 102 outputs a signal after frequency conversion (hereinafter referred to as IF1 signal) to a BPF (Band Pass Filter) 103. The received signal includes a signal in a desired band (that is, a relay band of the relay device 100) including an LTE signal and a 3G signal, and a signal in a frequency band other than the desired band (for example, a signal from another communication carrier). Is included. In addition to the data signal, the LTE signal and the 3G signal include a pilot signal (reference signal) known on the transmission / reception side and a transmission power of the pilot signal on the transmission side (in this case, the LTE base station and the 3G base station). And a notification signal including information indicating a value.

  The BPF 103 passes only the relay band (desired band including the LTE signal and the 3G signal) of the relay apparatus 100 among the signals (IF1 signal) input from the first frequency conversion unit 102. As a result, signals in bands other than the desired band (for example, signals from other communication carriers) are suppressed. Then, the BPF 103 outputs the passed signal to the distributor 104.

  The distributor 104 outputs the signal input from the BPF 103 to the second frequency conversion unit 110-1 and the second frequency conversion unit 110-2. That is, the distributor 104 distributes the signal input from the BPF 103 to each processing system.

  The signal detection unit 105 has a carrier sensing function, and from the received signal received via the antenna 101, the frequency arrangement (carrier arrangement) of each signal within the relay band of the relay apparatus 100 and the modulation method of each signal Etc. are detected. Then, the signal detection unit 105 outputs information including the detected frequency arrangement and modulation scheme to the frequency control unit 107 of the control unit 106.

  The control unit 106 includes a frequency control unit 107 and a gain control unit 108, controls frequency conversion for dividing the LTE signal and the 3G signal, and individually controls the amplification gain for the LTE signal and the 3G signal.

  First, the frequency control unit 107 of the control unit 106, based on the frequency arrangement indicated in the information input from the signal detection unit 105, out of all frequency bands (that is, relay bands) to which the LTE signal and 3G signal are allocated. A boundary frequency that is a boundary between the frequency to which the LTE signal is allocated and the frequency to which the 3G system signal is allocated is specified. Then, the frequency control unit 107 determines the frequency of the local signal generated by the local oscillator 109-1 and the local signal generated by the local oscillator 109-2 based on the specified boundary frequency and the cutoff frequency of the LPF. Control the frequency. Here, the frequency control unit 107 controls the frequency of the local signal generated by the local oscillator 109-1 so that the frequency is lower than the center frequency of the IF1 signal. Further, the frequency control unit 107 controls the frequency of the local signal generated by the local oscillator 109-2 so that the frequency is higher than the center frequency of the IF1 signal.

  The gain control unit 108 of the control unit 106 controls the amplification gain in the amplifiers 112-1 and 112-2 based on the pilot signal input from the demodulation unit 118 and information indicating the transmission power value of the pilot signal. . Specifically, gain control section 108 first measures the received power value of the pilot signal from the LTE base station and the received power value of the pilot signal from the 3G base station, which are input from demodulation section 118. . Next, the gain control unit 108 determines the propagation path loss value (path loss, PathLoss shown in the above equation (1)) for each system based on the difference between the measured reception power value and the transmission power value input from the demodulation unit 118. Is calculated. Then, the gain control unit 108 individually sets the amplification gain G of the LTE signal and the amplification gain G of the 3G signal, for example, according to the above equation (1). The gain control unit 108 controls the amplification gain so that the input level of the signal to the demodulation unit 118 is optimized when the demodulation signal is demodulated by the demodulation unit 118, and the antenna 117 is used for relay transmission to the relay destination. The amplification gain is controlled so that the output level from is optimal.

  The local oscillator 109-1 generates a local signal (lower local signal) having a frequency (here, a frequency lower than the center frequency of the IF1 signal) instructed by the frequency control unit 107, and the generated local signal is a second frequency. The data is output to the conversion unit 110-1.

  The local oscillator 109-2 generates a local signal (upper local signal) having a frequency (here, a frequency higher than the center frequency of the IF1 signal) instructed by the frequency control unit 107, and the generated local signal is a second frequency. The data is output to the conversion unit 110-2.

  The second frequency converters 110-1 and 110-2 use the local signals input from the local oscillators 109-1 and 109-2, respectively, and distribute in one of the two processing systems. The frequency arrangement of the IF1 signal (received signal) input from the receiver 104 is inverted, and the IF signal (received signal) input to each of the two processing systems and the frequency to which the LTE signal is assigned are 3G The IF1 signal (received signal) input from the distributor 104 is frequency-converted so that the boundary frequency that is the boundary with the frequency to which the signal is assigned is matched.

  Specifically, the second frequency conversion unit 110-1 performs frequency conversion of the IF1 signal input from the distributor 104 using the local signal (lower local signal) input from the local oscillator 109-1. Then, second frequency conversion section 110-1 outputs the signal after frequency conversion (hereinafter referred to as IF2-A signal) to LPF 111-1. Here, the IF2-A signal has the same frequency arrangement as the IF1 signal.

  The second frequency conversion unit 110-2 frequency-converts the IF1 signal input from the distributor 104 using the local signal (upper local signal) input from the local oscillator 109-2. Then, the second frequency conversion unit 110-2 outputs the frequency-converted signal (hereinafter referred to as IF2-B signal) to the LPF 111-2. Here, the IF2-B signal has a frequency arrangement obtained by inverting the frequency arrangement of the IF1 signal. Further, in the IF2-A signal and IF2-B signal, the frequency arrangement of the signals is inverted, and the boundary frequency that is the boundary between the frequency to which the LTE signal is allocated and the frequency to which the 3G signal is allocated matches. . Further, the boundary frequency matches the cutoff frequency set in advance in the LPFs 111-1 and 111-2.

  The LPFs 111-1 and 111-2 are pre-set cutoff frequencies in the frequency bands to which the IF2-A signal and the IF2-B signal respectively input from the second frequency conversion units 110-1 and 110-2 are assigned. The low frequency component (lower signal) below the frequency is passed. Thereby, in each processing system, a high frequency component (upper signal) is suppressed among relay bands. Here, of the LPFs 111-1 and 111-2, a signal (low frequency component) extracted on one side is an LTE signal, and a signal (low frequency component) extracted on the other side is a 3G signal. In other words, the LPFs 111-1 and 111-2 divide the LTE signal and the 3G signal by multiplying each processing system by the same LPF that allows components below the boundary frequency to pass. Then, the LPFs 111-1 and 111-2 output the obtained signals (LTE signal and 3G signal) to the amplifiers 112-1 and 112-2, respectively.

  The amplifiers 112-1 and 112-2 are variable gain amplifiers, and amplify signals input from the LPFs 111-1 and 111-2 in accordance with instructions from the gain control unit 108. Then, the amplifiers 112-1 and 112-2 output the amplified signals to the switches 113-1 and 113-2, respectively.

  The switches 113-1 and 113-2 output the destinations of the signals input from the amplifiers 112-1 and 112-2, respectively, to the second frequency converters 114-1 and 114-2 (that is, during relay amplification processing) And the demodulator 118 (that is, at the time of demodulation processing).

  The second frequency converters 114-1 and 114-2 use the same frequency as that of the local signals in the local oscillators 109-1 and 109-2, respectively, and IF2− inputted from the switches 113-1 and 113-2, respectively. Frequency conversion is performed on the A signal and the IF2-B signal. Then, the second frequency converters 114-1 and 114-2 output the frequency-converted signal (that is, the IF1 signal) to the synthesizer 115.

  The synthesizer 115 synthesizes the signal input from the second frequency conversion unit 114-1 and the signal input from the second frequency conversion unit 114-2. Then, the synthesizer 115 outputs the synthesized signal to the first frequency conversion unit 116.

  The first frequency conversion unit 116 performs frequency conversion on the combined signal (IF1 signal) input from the combiner 115 using the same frequency as the frequency used in the first frequency conversion unit 102. Then, the first frequency conversion unit 116 relays and transmits the signal after frequency conversion (that is, the RF signal) via the antenna 117.

  The demodulator 118 demodulates the notification signal included in the signal input from the switch 113-1 and the notification signal included in the signal input from the switch 113-2. Demodulation section 118 then outputs information indicating the pilot signal included in the signals input from switches 113-1 and 113-2 and information indicating the transmission power value of the pilot signal included in the broadcast signal to gain control section 108. To do. That is, the demodulation unit 118 outputs, to the gain control unit 108, pilot signals transmitted from the LTE base station and the 3G base station, and information indicating the transmission power values of the pilot signals in the LTE base station and the 3G base station.

  Next, the operation of relay apparatus 100 (FIG. 1) according to the present embodiment will be described in detail.

  In the following description, the relay device 100 receives the signal (input RF signal) shown in FIG. In addition, the received signal shown in FIG. 2 includes a desired signal assigned to a frequency band (that is, a relay band of the relay apparatus 100) 2100 MHz to 2120 MHz (20 MHz bandwidth) shared by the LTE system and the 3G system, Signals other than desired signals (signals of other communication carriers) allocated to bands other than 2100 MHz to 2120 MHz are included. In addition, as shown in FIG. 2, signals are assigned to 2100 MHz to 2120 MHz every 5 MHz bandwidth. Specifically, in FIG. 2, the LTE signal is allocated to a 5 MHz bandwidth of 2100 MHz to 2105 MHz, and three 3G signals are allocated to each 5 MHz bandwidth of 2105 MHz to 2120 MHz. Note that the bandwidth of the LTE signal is variable in a bandwidth of 1.4 MHz to 20 MHz, for example.

  Further, the cutoff frequency set in advance in the LPF 111-1 and the LPF 111-2 of the relay apparatus 100 (FIG. 1) is 45 MHz.

  Here, in relay apparatus 100, the processing system of local oscillator 109-1 to second frequency conversion unit 114-1 is a processing system for separating the LTE signal from the received signal shown in FIG. Similarly, in relay apparatus 100, the processing system of local oscillator 109-2 to second frequency conversion unit 114-2 is a processing system for separating the 3G signal from the received signal shown in FIG.

  First, the first frequency converter 102 converts the frequency of the received signal (RF signal) shown in FIG. 2 to obtain a signal (IF1 signal) after frequency conversion shown in the uppermost stage of FIG. That is, the signal in the frequency band of 2100 MHz to 2120 MHz (center frequency: 2110 MHz) shown in FIG. 2 is converted into the signal in the frequency band of 490 MHz to 510 MHz (center frequency: 500 MHz).

  Next, the BPF 103 passes only the frequency band of 490 MHz to 510 MHz corresponding to the relay band of the relay device 100 in the IF1 signal shown in FIG.

  Further, the frequency control unit 107 of the control unit 106 is based on the frequency arrangement input from the signal detection unit 105, and the frequency to which the LTE signal is allocated in the entire band (2100 MHz to 2120 MHz) of the reception signal shown in FIG. And the boundary frequency between the frequency to which the 3G signal is allocated is specified as 2105 MHz. This corresponds to 495 MHz in the IF1 signal after the first frequency conversion processing shown in the uppermost part of FIG.

  Further, the frequency control unit 107 inverts the frequency arrangement of the reception signal input to one of the two processing systems (here, the processing system to which the local oscillator 109-2 belongs), and The frequencies of the local signals generated by the local oscillators 109-1 and 109-2 are set so that the boundary frequencies are matched between the received signals input to the two processing systems. At this time, the frequency control unit 107 further generates frequencies of local signals generated by the local oscillators 109-1 and 109-2 so as to coincide with a cutoff frequency of 45 MHz used in both the LPFs 111-1 and 111-2. Set.

  Also, the frequency control unit 107 controls the frequency of the local signal generated by the local oscillator 109-1 so that the frequency is lower than the center frequency 500 MHz of the IF1 signal shown in FIG. Further, the frequency control unit 107 controls the frequency of the local signal generated by the local oscillator 109-2 so that the frequency is higher than the center frequency 500 MHz of the IF1 signal shown in FIG.

  Here, the frequency-converted signal with a local signal having a frequency lower than the center frequency of the IF1 signal has a frequency corresponding to the difference between the center frequency of the IF1 signal and the frequency of the local signal as the center frequency, and the frequency arrangement of the IF1 signal. And the same frequency arrangement. On the other hand, a frequency-converted signal with a local signal having a frequency higher than the center frequency of the IF1 signal has a frequency corresponding to the difference between the center frequency of the IF1 signal and the frequency of the local signal as the center frequency, The frequency arrangement is reversed.

  For example, in the uppermost stage of FIG. 3, in the frequency band of 490 MHz to 510 MHz, the boundary frequency between the LTE signal and the 3G signal is 495 MHz, which is 5 MHz lower than the center frequency of 500 MHz.

  Here, in the IF2 signal (here, the IF2-A signal that is the output of the second frequency converter 110-1) having the same frequency arrangement as the IF1 signal, the boundary frequency between the LTE signal and the 3G signal is the IF1 signal. Similarly to the above, the frequency is 5 MHz lower than the center frequency. On the other hand, in the IF2 signal whose frequency arrangement is inverted from the IF1 signal (here, the IF2-B signal that is the output of the second frequency converter 110-2), the boundary frequency between the LTE signal and the 3G signal is the IF1 signal. Conversely, the frequency is higher by 5 MHz than the center frequency.

  That is, the frequency control unit 107 sets the local oscillator 109-so that the frequency (boundary frequency) lower by 5 MHz than the center frequency of the signal after the second frequency conversion is 45 MHz (that is, the center frequency is 50 MHz). The frequency of the local signal generated at 1 may be set. Similarly, the frequency control unit 107 sets the local oscillator 109 so that the frequency (boundary frequency) higher by 5 MHz than the center frequency of the signal after the second frequency conversion is 45 MHz (that is, the center frequency is 40 MHz). The frequency of the local signal generated at -2 may be set.

  Therefore, the frequency control unit 107 generates a frequency of 450 MHz, which is lower than the center frequency of the IF1 signal 500 MHz shown in FIG. 3 and has a difference from the center frequency of the IF1 signal of 50 MHz (the center frequency of the IF2-A signal). Set to 1. Similarly, the frequency control unit 107 generates a frequency 540 MHz that is higher than the center frequency of the IF1 signal 500 MHz shown in FIG. 3 and that has a difference from the center frequency of the IF1 signal of 40 MHz (the center frequency of the IF2-B signal). Set to -1.

  Therefore, the second frequency conversion unit 110-1 performs frequency conversion on the IF1 signal shown in the uppermost part of FIG. 3 using the 450 MHz local signal generated by the local oscillator 109-1. Thereby, as shown in FIG. 3, the IF1 signal of 490 MHz to 510 MHz is converted into the IF2-A signal of 40 MHz to 60 MHz (center frequency 50 MHz). The frequency arrangement of the IF2-A signal shown in FIG. 3 (that is, the LTE signal, the 3G signal, the 3G signal, and the 3G signal) in order from the low frequency side is the same as the frequency arrangement of the IF1 signal shown at the top of FIG. In the IF2-A signal shown in FIG. 3, the boundary frequency between the LTE signal and the 3G signal is 45 MHz (the cut-off frequency of the LPF 111-1).

  On the other hand, the second frequency conversion unit 110-2 frequency-converts the IF1 signal shown in the uppermost part of FIG. 3 using the 540 MHz local signal generated by the local oscillator 109-2. As a result, as shown in FIG. 3, the IF1 signal of 490 MHz to 510 MHz is converted into an IF2-B signal of 30 MHz to 50 MHz (center frequency 40 MHz). The frequency arrangement of the IF2-B signal shown in FIG. 3 (that is, the 3G signal, 3G signal, 3G signal, and LTE signal in order from the low frequency side) is a frequency arrangement obtained by inverting the frequency arrangement of the IF1 signal shown in the uppermost stage of FIG. Become. In the IF2-B signal shown in FIG. 3, the boundary frequency between the 3G signal and the LTE signal is 45 MHz (the cut-off frequency of the LPF 111-2).

  Next, as shown in FIG. 3, the LPF 111-1 extracts only the LTE signal (5 MHz bandwidth of 40 MHz to 45 MHz) by passing only the frequency band of 45 MHz or less out of the frequency band of 40 MHz to 60 MHz. . Further, as shown in FIG. 3, the LPF 111-2 passes three 3G signals (three 5 MHz bandwidths within 30 MHz to 45 MHz) by passing only a frequency band of 45 MHz or less among the frequency bands of 30 MHz to 50 MHz. ) Only.

  That is, the LPF 111-1 and the LPF 111-2 divide the received signal received by the relay device 100 into the LTE signal and the 3G signal. Specifically, the LPF 111-1 and the LPF 111-2 pass the same filter that passes a component having a boundary frequency of 45 MHz or less in the two processing systems to the received signal after the frequency conversion (IF2-A signal in the LPF 111-1; The LPF 111-2 divides the LTE signal and the 3G signal by multiplying the IF2-B signal).

  The LTE signal obtained by the LPF 111-1 and the 3G signal obtained by the LPF 111-2 are input to the demodulator 118 via the switches 113-1 and 113-2. Demodulation section 118 then outputs the pilot signal included in the LTE signal and information indicating the transmission power value of the pilot signal to gain control section 108 of control section 106. Similarly, demodulation section 118 outputs a pilot signal included in the 3G signal and information indicating the transmission power value of the pilot signal to gain control section 108 of control section 106.

  Then, for each of the LTE signal and 3G signal, gain control section 108 compares the received power value measured from the pilot signal with the transmission power value input from demodulating section 118 to determine a propagation path loss (path loss) value. Can be calculated. As described above, the gain control unit 108 can individually control the amplification gain for the LTE signal and the 3G signal.

  Therefore, as illustrated in FIG. 3, the amplifier 112-1 amplifies the LTE signal using the amplification gain set by the gain control unit 108 based on the propagation path loss (path loss) value of the LTE signal. Similarly, as shown in FIG. 3, the amplifier 112-2 amplifies the 3G signal using the amplification gain set by the gain control unit 108 based on the propagation path loss (path loss) value of the 3G signal.

  Then, the relay device 100 includes a second frequency conversion process performed by the second frequency conversion units 114-1 and 114-2, an LTE signal and 3G signal combination process performed by the combiner 115, and a first frequency conversion unit 116 configured by the first frequency conversion unit 116. A frequency conversion process is performed to obtain a signal (output RF signal) shown at the bottom of FIG.

  In this way, the relay device 100 divides the LTE signal and the 3G signal allocated to the frequency band shared by the LTE system and the 3G system (the relay band of the relay device 100). That is, the relay device 100 can individually receive signals (LTE signal and 3G signal) corresponding to two different systems. That is, the relay device 100 can receive the LTE signal and the 3G signal without deterioration of the reception characteristics. Therefore, the relay apparatus 100 can demodulate the signals corresponding to the two systems without interfering with each other.

  Furthermore, the relay apparatus 100 can amplify each signal corresponding to the two systems with an appropriate amplification gain by individually amplifying each signal (LTE signal and 3G signal) corresponding to the two systems. . Specifically, as illustrated in FIG. 2, even when the received power of the LTE signal is smaller than the received power of the 3G signal, the relay apparatus 100 individually controls the amplification gain for the LTE signal and the 3G signal. Thus, as shown at the bottom of FIG. 3, the received power of each signal can be appropriately amplified.

  Next, a case where the input RF signal shown in FIG. 4 is received instead of the input RF signal shown in FIG. 2 will be described.

  In FIG. 4, 3G signals are allocated to two 5 MHz bandwidths of 2100 MHz to 2110 MHz in the frequency band of 2100 MHz to 2120 MHz (relay band of the relay device 100), and one LTE signal is allocated to the 10 MHz bandwidth of 2110 MHz to 2120 MHz. Only the assigned point is different from FIG. Further, the cutoff frequency in the LPFs 111-1 and 111-2 is set to 45 MHz as described above.

  Here, in relay apparatus 100, the processing system of local oscillator 109-1 to second frequency conversion unit 114-1 is a processing system for separating the 3G signal from the received signal shown in FIG. Similarly, in relay apparatus 100, the processing system of local oscillator 109-2 to second frequency conversion unit 114-2 is a processing system for separating the LTE signal from the received signal shown in FIG.

  Therefore, the frequency control unit 107 of the control unit 106 is based on the frequency arrangement input from the signal detection unit 105, and the frequency to which the LTE signal is allocated in the entire band (2100 MHz to 2120 MHz) of the reception signal shown in FIG. And the boundary frequency between the frequency to which the 3G signal is allocated is specified as 2110 MHz. This corresponds to 500 MHz (that is, the center frequency of the IF1 signal) in the IF1 signal after the first frequency conversion processing shown in the uppermost stage of FIG.

  Therefore, the frequency control unit 107 generates a frequency 455 MHz that is lower than the center frequency of the IF1 signal 500 MHz shown in FIG. 5 and has a difference of 45 MHz (the center frequency of the IF2-A signal) from the center frequency of the IF1 signal. Set to 1. Thereby, in the 2nd frequency conversion part 110-1, as shown in FIG. 3, IF2-A signal of 35 MHz-55 MHz (center frequency 45MHz) is obtained. The frequency arrangement of the IF2-A signal shown in FIG. 5 (that is, the 3G signal, the 3G signal, and the LTE signal in order from the low frequency side) is the same as the frequency arrangement of the IF1 signal shown at the top of FIG.

  Further, the frequency control unit 107 generates a frequency 545 MHz that is higher than the center frequency 500 MHz of the IF1 signal shown in FIG. 5 and has a difference from the center frequency of the IF1 signal of 45 MHz (the center frequency of the IF2-B signal). Set to 1. Thereby, in the 2nd frequency conversion part 110-2, as shown in FIG. 3, IF2-B signal of 35 MHz-45 MHz (center frequency 45MHz) is obtained. The frequency arrangement of the IF2-B signal shown in FIG. 5 (that is, the LTE signal, the 3G signal, and the 3G signal in order from the low frequency side) is a frequency arrangement obtained by inverting the frequency arrangement of the IF1 signal shown in the uppermost stage of FIG.

  As a result, as shown in FIG. 5, the LPF 111-1 and the LPF 111-2 pass only a frequency band having a cutoff frequency of 45 MHz or less as in FIG. 3, thereby allowing a 3G signal (35 MHz in the LPF 111-1 in FIG. 5). ˜45 MHz) and the LTE signal (35 MHz to 45 MHz in the LPF 111-2 in FIG. 5) can be divided.

  In this way, as illustrated in FIGS. 3 and 5, the relay device 100 can perform the LPF 111-1 and the LPF 111- even when the frequency band to which the LTE signal is allocated and the frequency band to which the 3G signal is allocated are variable. 2 uses filters having the same characteristics (cutoff frequency: 45 MHz). Then, the relay device 100 changes the local signal (lower local signal and upper local signal) used in the second frequency conversion, that is, the center frequency of the signal after the second frequency conversion, according to the variable frequency band allocation. Let Specifically, in FIG. 3 and FIG. 5, the relay device 100 determines the boundary frequency between the LTE signal and the 3G signal in both of the two processing systems regardless of the frequency band allocation of the LTE signal and the 3G signal. The frequency of the local signal is controlled so that the cutoff frequency becomes 45 MHz in the LPFs 111-1 and 111-2.

  Here, if a different filter is used each time the frequency band allocation of each signal changes, the frequency characteristics to be suppressed differ for each filter. On the other hand, the relay device 100 (second frequency conversion units 110-1 and 110-2) inverts the frequency arrangement of the received signal input to one of the two processing systems, and The received signals input to the two processing systems are frequency-converted so that the boundary frequencies are matched between the received signals input to the two processing systems. Thereby, in the relay apparatus 100, even if the frequency band to which the LTE signal is allocated and the frequency band to which the 3G signal is allocated are variable, it is possible to use filters with the same characteristics, and thus it is possible to always obtain signals with the same characteristics. it can.

  Thus, according to the present embodiment, the relay device divides each signal corresponding to a plurality of systems sharing a frequency band. As a result, the relay apparatus can individually receive signals corresponding to a plurality of systems, and thus can demodulate the signals without deteriorating the reception characteristics. Furthermore, the relay apparatus can amplify each signal with an appropriate amplification gain by individually controlling the amplification gain of each signal. Furthermore, even when the bandwidth of the LTE signal is variable, that is, when the frequency band allocation of each signal is variable, the relay device always uses the same filter (the filter having the same frequency characteristic) to Can be divided. Therefore, according to the present embodiment, even when a plurality of systems share a frequency band, appropriate automatic gain control can be performed on a signal corresponding to each system.

  In the present embodiment, a case has been described in which the relay apparatus uses LPFs (LPFs 111-1 and 111-2 shown in FIG. 1) to separate signals corresponding to different systems. However, in the present invention, in the relay device, as a filter that separates signals corresponding to different systems, the same filter may be used in a processing system corresponding to each system. For example, HPF or BPF may be used instead of LPF. For example, the relay apparatus 100 uses an HPF instead of the LPF 111-1 and the LPF 111-2 illustrated in FIG. 3 to pass a component (3G signal) of 45 MHz or more out of an IF2-A signal of 40 MHz to 60 MHz, and 30 MHz A component (LTE signal) of 45 MHz or higher may be passed through the IF2-B signal of ˜50 MHz. In other words, the relay apparatus 100 uses the same filter that passes a component having a boundary frequency of 45 MHz or more in the two processing systems as a received signal (IF2-A signal in one processing system, IF2 in the other processing system). -B signal) to divide the LTE signal and the 3G signal.

  Moreover, although the case where the LTE system and the 3G system share the frequency band has been described in the present embodiment, the system to which the present invention can be applied is not limited to the LTE system and the 3G system. For example, the present invention may be applied to an LTE system and an LTE-Advanced system that is an advanced form of the LTE system. In the present embodiment, a case has been described in which a plurality of signals corresponding to a plurality of systems are mixed in the relay band of the relay device. However, for example, the present invention can be applied even when only the signal corresponding to the LTE system (or 3G system) is included in the relay band of the relay device. That is, the relay device may divide a plurality of signals (signals of the same system) included in the relay band into a plurality of systems and perform automatic gain control individually for each of the divided signals. For example, the relay device divides the received signal into an end of the relay band, that is, a band near the boundary with another communication carrier and a band near the center of the relay band. The relay apparatus individually performs automatic gain control on a signal assigned to a band near the boundary with another communication carrier and a signal assigned to a band near the center of the relay band. For example, the relay apparatus can suppress interference that can be given to other communication carriers by making the amplification gain of the band near the boundary with other communication carriers smaller than the amplification gain of the central band of the relay band. it can.

  Further, in the present embodiment, the case has been described where the relay apparatus relays and transmits the signal transmitted from the base station to the terminal (that is, downlink). However, the relay apparatus can also apply the present invention to the case where the signal transmitted from the terminal is relayed to the base station (that is, the uplink).

  The present invention is useful for a relay apparatus that relays and transmits a received signal including a plurality of signals sharing a frequency band.

100 Relay device 101, 117 Antenna 102, 116 First frequency converter 103 BPF
104 Divider 105 Signal Detection Unit 106 Control Unit 107 Frequency Control Unit 108 Gain Control Unit 109 Local Oscillator 110, 114 Second Frequency Conversion Unit 111 LPF
112 Amplifier 113 Switch 115 Synthesizer 118 Demodulator

Claims (4)

A relay device that amplifies and relays a received signal including a first signal and a second signal,
Dividing means for dividing the received signal into the first signal and the second signal;
Control means for individually controlling the amplification gain of the first signal and the amplification gain of the second signal;
A relay device comprising: A first processing system for separating the first signal from the received signal; and a second processing system for separating the second signal from the received signal;
A specifying unit that specifies a boundary frequency that is a boundary between a frequency band to which the first signal is allocated and a frequency band to which the second signal is allocated among all frequency bands to which the received signal is allocated; ,
The received signal input to the first processing system, and the frequency arrangement of the received signal input to either one of the first processing system and the second processing system is inverted. And the received signal input to the second processing system, the received signals input to the first processing system and the second processing system are respectively frequency-matched so that the boundary frequency is matched. Conversion means for converting, and
In the first processing system and the second processing system, the dividing unit passes a filter that passes the component below the boundary frequency or the component that exceeds the boundary frequency to the received signal after frequency conversion, respectively. Dividing the first signal and the second signal by multiplying,
The relay apparatus according to claim 1. The conversion means has a frequency higher than the center frequency of the received signal that is frequency-converted from an RF signal to an IF signal in any one of the first processing system and the second processing system. The received signal is frequency converted using a local signal, and in the other processing system, the received signal is frequency converted using a local signal having a frequency lower than the center frequency.
The relay apparatus according to claim 2. A relay method in a relay apparatus that amplifies and relays a received signal including a first signal and a second signal,
A dividing step of dividing the received signal into the first signal and the second signal;
A control step for individually controlling the amplification gain of the first signal and the amplification gain of the second signal;
A relay method comprising:

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