JP5407812B2 - Wireless communication apparatus, wireless communication system, and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication device, a wireless communication system, and a wireless communication method.

  Conventionally, a pilot channel relay device is known as one of wireless communication devices. In this relay apparatus, a downlink signal transmitted from a predetermined radio base station is received and input by a first antenna having directivity. Then, the relay apparatus selects and amplifies only the signal belonging to the frequency band of the downlink signal transmitted from the radio base station, and transmits the amplified signal via the second antenna. In a range in which a signal transmitted from the relay device can be received, the received power level of the downlink signal transmitted from the predetermined radio base station is higher than the received power level of the downlink signal transmitted from another radio base station. Therefore, the mobile device selects the wireless base station that is the transmission source of the signal relayed by the relay device as the communication destination (see, for example, Patent Document 1).

JP 2006-165861 A

  However, a conventional wireless communication apparatus used as a relay apparatus includes an apparatus that amplifies a received signal as it is and does not perform demodulation or decoding of the received signal and transmits it again. In such a wireless communication apparatus, when the received signal is transmitted again, the synchronization signal and the broadcast signal transmitted by the base station cannot be identified. The received signal includes a data signal in addition to the synchronization signal and the notification signal. Therefore, there is a problem that the wireless quality cannot be determined.

  An object of the present invention is to provide a wireless communication apparatus, a wireless communication system, and a wireless communication method that can determine wireless quality based on a received signal.

  The wireless communication apparatus includes a first measurement unit, a second measurement unit, and an estimation unit. The first measurement unit measures received power in a first frequency band of a downlink signal including a reference signal. The second measurement unit measures received power in the second frequency band of the downlink signal. The estimating unit estimates the received power of the reference signal based on the received power measured by the first measuring unit and the received power measured by the second measuring unit.

  According to the wireless communication device, the wireless communication system, and the wireless communication method, there is an effect that the wireless quality can be determined based on the received signal.

1 is a block diagram illustrating an example of a wireless communication system according to a first embodiment. 1 is a block diagram illustrating an example of a wireless communication apparatus according to Embodiment 1. FIG. 3 is a flowchart illustrating an example of a wireless communication method according to the first embodiment. It is a schematic diagram which shows an example of the radio frame of an OFDMA system. FIG. 3 is a block diagram illustrating an example of a wireless communication apparatus according to a second embodiment. FIG. 10 is a characteristic diagram illustrating an example of downlink received power in the wireless communication apparatus according to the second embodiment. FIG. 10 is a characteristic diagram illustrating another example of downlink received power in the wireless communication apparatus according to the second embodiment. 10 is a flowchart illustrating an example of a wireless communication method according to a second embodiment. FIG. 9 is a block diagram illustrating an example of a wireless communication apparatus according to a third embodiment. 10 is a flowchart illustrating an example of a wireless communication method according to a third embodiment. FIG. 10 is a block diagram illustrating an example of a wireless communication apparatus according to a fourth embodiment. 10 is a flowchart illustrating an example of a wireless communication method according to a fourth embodiment. 10 is a flowchart illustrating an example of a wireless communication method according to a fourth embodiment. FIG. 10 is a block diagram illustrating an example of a wireless communication apparatus according to a fifth embodiment. 10 is a flowchart illustrating an example of a wireless communication method according to a fifth embodiment. FIG. 10 is a block diagram illustrating an example of a wireless communication apparatus according to a sixth embodiment. 12 is a flowchart illustrating an example of a wireless communication method according to a sixth embodiment.

  Exemplary embodiments of a wireless communication device, a wireless communication system, and a wireless communication method will be described below in detail with reference to the accompanying drawings. A radio communication apparatus, a radio communication system, and a radio communication method measure received power for each of a first frequency band and a second frequency band of a downlink signal including a reference signal, and reference signal based on both received power The wireless quality is determined by estimating the received power. Downlink signals go from the base station to the terminal station, or from the base station to the terminal station via the relay station. In the following description of each embodiment, the same components are denoted by the same reference numerals, and redundant descriptions are omitted.

Example 1
FIG. 1 is a block diagram of an example of a wireless communication system according to the first embodiment. As shown in FIG. 1, a wireless communication system includes a base station (BS) 1, a relay station (RS) 2 that operates as a wireless communication device, and terminal stations (MS # 1, MS # 2, MS: Mobile Station) 3 and 4 are included. In FIG. 1, a circle indicated by reference numeral 5 indicates a communicable area (cell or sector) of the base station 1 with the base station 1, and a circle indicated by reference numeral 6 indicates the base station 1 extended by the relay station 2. Indicates the communicable area. The relay station 2 improves, for example, the radio quality between the base station 1 and the terminal station 4 outside the communicable area 5 between the base station 1 and the base station 1. The relay station 2 may be installed fixedly on land or at sea, or installed on a moving vehicle such as a bus or train.

FIG. 2 is a block diagram of an example of the wireless communication apparatus according to the first embodiment. As illustrated in FIG. 2, the relay station device 11 that operates as a wireless communication device includes a first measurement unit 12, a second measurement unit 13, and an estimation unit 14. The first measurement unit 12 measures received power in a first frequency band of a downlink signal including a reference signal such as a synchronization signal or a broadcast signal. The second measuring unit 13 measures the received power in the second frequency band of the downlink signal. The estimation unit 14 estimates the reception power of the reference signal based on the reception power measured by the first measurement unit 12 and the reception power measured by the second measurement unit 13.

FIG. 3 is a flowchart of an example of the wireless communication method according to the first embodiment. As shown in FIG. 3, when the processing is started, first, the relay station apparatus 11 uses the first measurement unit 12 to measure the received power in the first frequency band of the downlink signal including the reference signal. (First measurement step, step S1). In addition, the relay station apparatus 11 uses the second measurement unit 13 to measure the received power in the second frequency band of the downlink signal (second measurement step, step S2). Either step S1 or step S2 may be performed first or simultaneously. Next, the relay station apparatus 11 estimates the reception power of the reference signal based on the reception power measured in the first measurement step and the reception power measured in the second measurement step by the estimation unit 14 (estimation). Step, step S3). And the relay station apparatus 11 complete | finishes a process.

  According to the first embodiment, since the reception power of the reference signal is estimated based on the reception power of the first frequency band and the reception power of the second frequency band, the relay station 2 (relay station apparatus 11) receives the reception signal. The wireless quality can be determined based on the received signal. At that time, the relay station apparatus 11 may not demodulate or decode the received downlink signal. That is, radio quality can be determined in a non-regenerative type relay station apparatus that transmits a received signal again without demodulating and decoding. Further, in the radio communication system in which the base station 1 periodically changes the transmission power of the synchronization signal and the broadcast signal, the relay station 2 can determine the status of the transmission power of the base station 1.

(Example 2)
An example of the wireless communication system according to the first embodiment is a system that performs wireless communication using an Orthogonal Frequency Division Multiple Access (OFDMA) system. In the second embodiment, an example in which the first embodiment is applied to an OFDMA wireless communication system will be described. The first embodiment can be applied not only to the OFDMA system but also to wireless communication systems using other communication systems.

Description of Radio Frame FIG. 4 is a schematic diagram illustrating an example of an OFDMA radio frame. As shown in FIG. 4, the radio frame 21 is divided into a plurality of symbols in the time axis direction. The radio frame 21 is divided into a plurality of subcarriers in the frequency axis direction. When the duplex system is a Frequency Division Duplex (FDD) system, the radio frame has the same configuration on the downlink and the uplink. On the downlink, a reference signal 22 such as a synchronization signal or a broadcast signal is periodically transmitted using a predetermined symbol of a predetermined subcarrier of the radio frame 21. When there is data such as control information and data information, the data signal 23 is transmitted using a region of the radio frame 21 to which the reference signal 22 is not assigned. As in the illustrated example, the reference signal 22 and the data signal 23 may be assigned to the same frequency band.

  An example of an OFDMA wireless communication system is a Long Term Evolution (LTE) system that is being standardized in the 3rd Generation Partnership Project (3GPP). In the LTE system, as an example of the reference signal, for example, Primary Synchronization Signal (PSS, primary synchronization signal), Secondary Synchronization Signal (SSS, secondary synchronization signal), or Physical Broadcast Channel (PB) is used. . The first embodiment can be applied not only to the LTE system but also to other wireless communication systems.

FIG. 5 is a block diagram of an example of a wireless communication apparatus according to the second embodiment. As shown in FIG. 5, the relay station device 31 that operates as a wireless communication device includes antenna units 32 and 33, coupling units 34 and 35, filter units 36, 37, 38, and 39, amplification units 40 and 41, and an adjustment unit 42. , 43, measurement units 44 and 45, an estimation unit 46, a power supply unit 47, and a storage unit 48. In FIG. 5, the solid arrow represents the signal line 49, the dotted line represents the control line 50, and the alternate long and short dash line represents the power supply line 51.

  The first antenna unit 32 receives a signal transmitted from a base station (not shown) or another relay station between the own station and the base station. The first antenna unit 32 transmits a signal to a base station (not shown) or another relay station between the own station and the base station. The second antenna unit 33 transmits a signal to a terminal station (not shown) or another relay station between the own station and the terminal station. The second antenna unit 33 receives a signal transmitted from a terminal station (not shown) or another relay station between the own station and the terminal station.

  The first coupling unit 34 outputs the signal input from the first antenna unit 32 to the first filter unit 36. The first combining unit 34 outputs the signal that has passed through the fourth filter unit 39 to the first antenna unit 32. The second coupling unit 35 outputs the signal that has passed through the second filter unit 37 to the second antenna unit 33. The second coupling unit 35 outputs the signal input from the second antenna unit 33 to the third filter unit 38.

  The 1st filter part 36, the 2nd filter part 37, the 3rd filter part 38, and the 4th filter part 39 pass the signal of the frequency band of a system. For example, when the duplex system is the FDD system, the frequency band through which the signals of the first filter unit 36 and the second filter unit 37 pass and the signals of the third filter unit 38 and the fourth filter unit 39 are transmitted. Is different from the frequency band through which the signal passes.

  The first measuring unit 44 measures the received power in the first frequency band for the signal that has passed through the first filter unit 36. The first frequency band includes the frequency of the reference signal. The second measuring unit 45 measures the received power in the second frequency band for the signal that has passed through the first filter unit 36. The second frequency band is, for example, one of the following three frequency bands. For example, the second frequency band may be a frequency band of the system excluding the first frequency band (see a first estimation example described later). The second frequency band may be a system frequency band (see a second estimation example described later). Further, the second frequency band may be a predetermined frequency band of the system frequency bands (see a third estimation example described later).

  The estimation unit 46 estimates the reception power of the reference signal based on the reception power measured by the first measurement unit 44 and the reception power measured by the second measurement unit 45. The estimation unit 46 determines whether or not the relay station device 31 performs the relay operation by comparing the estimated value of the received power of the reference signal and the threshold for operation determination. For example, the estimation unit 46 determines that the relay operation is performed when the estimated value of the received power of the reference signal is smaller than the threshold for operation determination, and the estimated value of the received power of the reference signal is smaller than the threshold for operation determination. If not, it may be determined that the relay operation is not performed.

  The first amplification unit 40 amplifies the signal that has passed through the first filter unit 36 and outputs the amplified signal to the second filter unit 37. The first adjustment unit 42 adjusts the amplification degree of the first amplification unit 40 by comparing the estimated value of the received power of the reference signal and the threshold value for determining the amplification degree. The second amplification unit 41 amplifies the signal that has passed through the third filter unit 38 and outputs the amplified signal to the fourth filter unit 39. The second adjustment unit 43 adjusts the amplification degree of the second amplification unit 41 by comparing the estimated value of the received power of the reference signal with the threshold value for determining the amplification degree.

  The storage unit 48 holds a threshold for determining operation, a threshold for determining amplification, and an amplification. The threshold for operation determination, the threshold for determining amplification, and the amplification are set in advance. A plurality of amplification factor determination thresholds and amplification factors may be set according to the estimated values of the received power of the reference signals. For example, the degree of amplification may be set to increase when the estimated value of the received power of the reference signal is small, and to decrease when the estimated value of the received power of the reference signal is large. The power supply unit 47 includes a first amplification unit 40, a second amplification unit 41, a first adjustment unit 42, a second adjustment unit 43, a first measurement unit 44, a second measurement unit 45, and an estimation unit 46. In addition, the storage unit 48 is supplied with a driving voltage for operating these units.

FIG. 6 is a characteristic diagram illustrating an example of downlink received power in the wireless communication apparatus according to the second embodiment. In FIG. 6, the frequency of the reference signal is included in the frequency band X. The frequency band of the system is Z. Y is a frequency band excluding the frequency band X in the system frequency band Z. The frequency band X corresponds to the first frequency band, and the frequency band Y corresponds to the second frequency band. Reference numeral 26 represents the received power of the reference signal, reference numeral 27 represents the received power of the data signal in the frequency band X, and reference numeral 28 represents the received power of the data signal in the frequency band Y. In the example shown in FIG. 6, the data signals are allocated almost evenly to the system frequency band. In the first estimation example, the first measurement unit 44 measures received power in the frequency band X. The received power in the frequency band X is the sum of the received power 26 of the reference signal and the received power 27 of the data signal in the frequency band X. The second measuring unit 45 measures the received power 28 of the data signal in the frequency band Y. The measured value of the received power in the frequency band X is A, and the measured value of the received power in the frequency band Y is B. The bandwidth of the frequency band X is Wx, and the bandwidth of the frequency band Y is Wy. In this case, the estimation unit 46 can estimate the received power P of the reference signal according to the following equation (1).
P = A−B × Wx / Wy (1)

Description of the method for estimating the received power of the reference signal (second estimation example) In the second estimation example, the frequency band X corresponds to the first frequency band, and the frequency band Z corresponds to the second frequency band. . The first measuring unit 44 measures received power in the frequency band X. The second measuring unit 45 measures the received power in the frequency band Z. The received power in the frequency band Z is the sum of the received power 26 of the reference signal, the received power 27 of the data signal in the frequency band X, and the received power 28 of the data signal in the frequency band Y. The measured value of the received power in the frequency band X is A, and the measured value of the received power in the frequency band Z is C. The bandwidth of the frequency band X is Wx, and the bandwidth of the frequency band Z is Wz. In this case, the estimation unit 46 can estimate the received power P of the reference signal according to the following equation (2).
P = A− (C−A) × Wx / Wz (2)

FIG. 7 is a characteristic diagram illustrating another example of downlink received power in the wireless communication apparatus according to the second embodiment. In FIG. 7, the frequency of the reference signal is included in the frequency band X. In the example shown in FIG. 7, the data signal is preferentially assigned from a predetermined frequency band W within the system frequency band. The frequency band X corresponds to the first frequency band, and the frequency band W corresponds to the second frequency band. Reference numeral 29 denotes reception power of the data signal in the frequency band W. In the third estimation example, the first measurement unit 44 measures received power in the frequency band X. The second measuring unit 45 measures the received power in the frequency band W. The measured value of the received power in the frequency band X is A, and the measured value of the received power in the frequency band W is D. The bandwidth of the frequency band X is Wx, and the bandwidth of the frequency band W is Ww. In this case, the estimation unit 46 can estimate the received power P of the reference signal according to the following equation (3).
P = A−D × Wx / Ww (3)

FIG. 8 is a flowchart of an example of the wireless communication method according to the second embodiment. As shown in FIG. 8, when the process is started, first, the relay station device 31 operates the power supply unit 47 (step S11). Accordingly, the first amplification unit 40, the second amplification unit 41, the first adjustment unit 42, the second adjustment unit 43, the first measurement unit 44, the second measurement unit 45, the estimation unit 46, and the storage A drive voltage is supplied to the unit 48, and these units operate.

  Next, the relay station device 31 receives the downlink signal transmitted from the base station. The received signal is passed to the first measurement unit 44 and the second measurement unit 45 via the first antenna unit 32, the first coupling unit 34, and the first filter unit 36. The first measurement unit 44 measures the received power in the first frequency band including the reference signal for the signal passed from the first filter unit 36. The second measurement unit 45 measures the received power in the second frequency band for the signal passed from the first filter unit 36. Based on the received power of the first frequency band measured by the first measuring unit 44 and the received power of the second frequency band measured by the second measuring unit 45, the estimating unit 46 Received power is estimated (step S12).

  Next, the relay station device 31 uses the estimation unit 46 to compare the estimated value of the received power of the reference signal with the threshold value for operation determination (step S13). As a result of the comparison, if the estimated value of the received power of the reference signal is not smaller than the threshold for operation determination (step S13: No), the relay station apparatus 31 is not relayed and the process returns to step S12, and step S12 And the process of step S13 is repeated. When the estimated value of the received power of the reference signal is smaller than the threshold for operation determination (step S13: Yes), the relay station device 31 uses the estimating unit 46 to determine the estimated value of the received power of the reference signal and determine the amplification degree. The threshold value is compared (step S14).

  The relay station device 31 determines the amplification degree in the first amplifying unit 40 and the second amplifying unit 41 based on the estimated value of the received power of the reference signal (step S15). Thereby, the amplification degree is determined to a magnitude corresponding to the radio quality estimated based on the estimated value of the received power of the reference signal. The relay station device 31 starts relaying a signal between the base station and the terminal station with the determined amplification degree. And it returns to step S12 and the relay station apparatus 31 implements operation | movement after step S12 periodically.

-Explanation of signal path at the time of relay In the downlink, a signal transmitted from a base station (not shown) or another relay station passes through the first antenna unit 32, the first coupling unit 34, and the first filter unit 36. Then, the signal is received by the first amplification unit 40 and amplified by the first amplification unit 40. The amplified signal is transmitted from the second antenna unit 33 to a terminal station (not shown) or another relay station via the second filter unit 37 and the second coupling unit 35. On the other hand, in the uplink, a signal transmitted from a terminal station (not shown) or another relay station passes through the second antenna unit 33, the second coupling unit 35, and the third filter unit 38, Are amplified by the second amplifying unit 41. The amplified signal is transmitted from the first antenna unit 32 to a base station (not shown) or another relay station via the fourth filter unit 39 and the first coupling unit 34.

  According to the second embodiment, since the reception power of the reference signal is estimated based on the reception power of the first frequency band and the reception power of the second frequency band, the relay station device 31 demodulates the received signal, The wireless quality can be determined without decoding. That is, even if the relay station device 31 is a non-regenerative type relay station device, the wireless quality can be determined. Further, in the wireless communication system in which the base station periodically changes the transmission power of the synchronization signal and the broadcast signal, the relay station device 31 can determine the state of the transmission power of the base station. Further, the relay station device 31 can determine whether or not to perform the relay operation based on the estimated value of the received power of the reference signal, and can perform or stop the relay operation.

  Note that the threshold for operation determination may be different between the downlink and the uplink, or the threshold for determining the amplification degree may be different. Also, the degree of amplification corresponding to the threshold for determining the degree of amplification may be different between the downlink and the uplink. In this way, if the threshold and the amplification factor are individually set for the downlink and the uplink, even if the radio quality is different between the downlink and the uplink, the downlink and the uplink are respectively set. Suitable relay can be performed. Also, instead of using the threshold value for determining the amplification degree, a mathematical expression for determining the amplification degree is prepared in advance, and the amplification degree may be determined based on the mathematical expression and the estimated value of the received power of the reference signal. Good. In addition, a table that preliminarily prepares a correspondence relationship between the measured value of the received power in the first frequency band and the measured value of the received power in the second frequency band and the estimated value of the received power of the reference signal is prepared. The received power of the reference signal may be estimated based on the table.

(Example 3)
FIG. 9 is a block diagram of an example of a wireless communication apparatus according to the third embodiment. The third embodiment is an example in which the second frequency band is dynamically switched in the second embodiment. As illustrated in FIG. 9, the relay station device 61 includes a plurality of second measurement units instead of the second measurement unit 45 in the relay station device 31 of the second embodiment. For example, in the example illustrated in FIG. 9, the relay station device 61 is provided with two second measurement units, a 2-1 measurement unit 62 and a 2-2 measurement unit 63. The relay station device 61 includes a switching unit 64.

  The 2-1 measuring unit 62 measures the received power in the frequency band of the system excluding the first frequency band including the reference signal, that is, the frequency band Y, as the second frequency band. The 2-2 measuring unit 63 measures the received power in a predetermined frequency band in the system frequency band, that is, the frequency band W, as the second frequency band. The switching unit 64 compares the received power measured by the 2-1 measuring unit 62 with the received power measured by the 2-2 measuring unit 63. For example, the switching unit 64 obtains a difference between the received power measured by the 2-1 measuring unit 62 and the received power measured by the 2-2 measuring unit 63.

  For example, the switching unit 64 selects the received power measured by the 2-1 measuring unit 62 as the received power in the second frequency band when the obtained difference is larger than the switching determination threshold. When the data signal is allocated almost evenly to the frequency band of the system, the difference between the two received powers is larger than the threshold value for switching determination. For example, the switching unit 64 receives the received power measured by the 2-2 measuring unit 63 as the received power in the second frequency band when the difference between the two received powers is not larger than the threshold value for switching determination. Select. When the data signal is preferentially assigned from a predetermined frequency band within the system frequency band, the difference between the two received powers does not become larger than the threshold for switching determination. The storage unit 48 holds a threshold value for switching determination. The threshold value for switching determination is set in advance. Other configurations are the same as those of the second embodiment.

FIG. 10 is a flowchart of an example of a second frequency band switching method in the wireless communication method according to the third embodiment. As shown in FIG. 10, when the process of switching the second frequency band is started, first, the 2-1 measuring unit 62 measures the received power of the frequency band Y (step S21). The 2-2 measuring unit 63 measures the received power in the frequency band W (step S22). Either step S21 or step S22 may be performed first or simultaneously. Next, the switching unit 64 obtains, for example, a difference between the received power measured by the 2-1 measuring unit 62 and the received power measured by the 2-2 measuring unit 63, and the difference is used for determination. Is compared with the threshold value (step S23).

  For example, when the obtained difference is larger than the switching determination threshold value (step S23: Yes), the switching unit 64 receives the reception power measured by the 2-1 measuring unit 62 as the reception power of the second frequency band. Electric power is selected (step S24). On the other hand, for example, when the obtained difference is not larger than the threshold value for switching determination (step S23: No), the switching unit 64 measures the received power in the second frequency band by the 2-2 measuring unit 63. The received power thus selected is selected (step S25). And the relay station apparatus 61 complete | finishes the process which switches a 2nd frequency band. The process of switching the second frequency band is performed when the relay station device 61 starts operation or periodically during operation. The process of estimating the received power of the reference signal and determining the amplification degree is the same as in the second embodiment.

  According to the third embodiment, the same effect as in the second embodiment can be obtained. In addition, the second frequency band that is the measurement target of the received power can be switched according to the data signal allocation situation. The 2-1 measuring unit 62 may measure the received power in the system frequency band, that is, the frequency band Z.

Example 4
FIG. 11 is a block diagram of an example of a wireless communication apparatus according to the fourth embodiment. The fourth embodiment is another example in which the second frequency band is dynamically switched in the second embodiment. As illustrated in FIG. 11, the relay station device 71 includes a second measurement unit 72 that measures received power in a temporary frequency band instead of the second measurement unit 45 in the relay station device 31 of the second embodiment. I have. The relay station device 71 includes a switching unit 73.

  The switching unit 73 subdivides the system frequency band into a plurality of frequency bands. The switching unit 73 sets the subdivided frequency bands in the second measurement unit 72 as temporary frequency bands. The switching unit 73 compares the received power of the temporary frequency band measured by the second measuring unit 72 with an allocation determination threshold value. When the received power of the temporary frequency band measured by the second measuring unit 72 is larger than the threshold for determination of assignment, the switching unit 73 has a temporary frequency band whose received power is larger than the threshold for determination of assignment. Increment the consecutive number of. For example, the switching unit 73 includes a counter that counts the continuous number of temporary frequency bands in which the received power is larger than the allocation determination threshold. The switching unit 73 compares the number of consecutive temporary frequency bands having received power larger than the allocation determination threshold value with the band determination threshold value.

  The switching unit 73 is configured such that the reception power is larger than the allocation determination threshold when the number of continuous frequency bands in which the reception power is larger than the allocation determination threshold is larger than the band determination threshold. A set of temporary frequency bands to be set is set as the frequency band of the second measurement unit 72. When the data signal is preferentially assigned from a predetermined frequency band in the system frequency band, the continuous number of temporary frequency bands whose received power is larger than the threshold value for assignment determination is It becomes larger than the threshold value.

  The switching unit 73 changes the frequency band of the system to the second measuring unit 72 when the continuous number of temporary frequency bands in which the received power is larger than the allocation determination threshold does not become larger than the band determination threshold. Set as the frequency band. When the data signal is allocated almost evenly to the system frequency band, the continuous number of temporary frequency bands in which the received power is larger than the allocation determination threshold value does not become larger than the band determination threshold value.

  The second measuring unit 72 measures the received power in the temporary frequency band set by the switching unit 73. The storage unit 48 holds a temporary frequency band width, an allocation determination threshold value, and a band determination threshold value. The temporary frequency band width, the allocation determination threshold, and the band determination threshold are set in advance. The storage unit 48 holds the received power in the temporary frequency band measured by the second measurement unit 72. Other configurations are the same as those of the second embodiment.

Description of Second Frequency Band Switching Method FIGS. 12 and 13 are flowcharts illustrating an example of the second frequency band switching method in the wireless communication method according to the fourth embodiment. As shown in FIG. 12, when the process of switching the second frequency band is started, first, the switching unit 73 sets a temporary frequency band in the second measurement unit 72 (step S31). Next, the second measuring unit 72 measures the received power in the set temporary frequency band (step S32). The measured received power is held in the storage unit 48. Then, the switching unit 73 determines whether or not the measurement of received power has been completed for all temporary frequency bands (step S33).

  When the measurement of received power is not completed for all temporary frequency bands (step S33: No), the switching unit 73 and the second measurement unit 72 change the temporary frequency band in order from, for example, the lower frequency band. However, the process of step S31 and step S32 is repeated. When the measurement of the received power is completed for all the temporary frequency bands (step S33: Yes), the switching unit 73 selects the temporary frequency bands from the storage unit 48, for example, in the order of lower frequency bands, and the temporary The received power in the frequency band is read (step S34). Next, the switching unit 73 compares the received power in the temporary frequency band with an allocation determination threshold value (step S35).

  When the received power in the temporary frequency band is not larger than the threshold for determination of allocation (step S35: No), as shown in FIG. 13, the switching unit 73 compares the continuous number with the threshold for determination of band. (Step S37). When the continuous number is not larger than the threshold for band determination (step S37: No), the switching unit 73 resets the continuous number to 0 (step S39), for example. Next, the switching unit 73 determines whether or not the comparison with the threshold value for assignment determination is completed for all temporary frequency bands (step S40). When the comparison with the threshold value for assignment determination has not been completed for all temporary frequency bands (step S40: No), the switching unit 73 changes the temporary frequency band in order from, for example, the lower frequency band, The processes after step S34 are repeated.

  If the received power in the temporary frequency band becomes larger than the threshold for determination of assignment while repeating the processing after step S34 (step S35: Yes), the switching unit 73 increments the continuous number (step S35). S36). In addition, when the received power in the temporary frequency band first selected in step S34 is larger than the allocation determination threshold (step S35: Yes), the switching unit 73 increments the continuous number (step S36). ). Next, the switching unit 73 determines whether or not the comparison with the threshold value for assignment determination is completed for all temporary frequency bands (step S40). When the comparison with the threshold value for determination of allocation is not completed for all temporary frequency bands (step S40: No), the process returns to step S34.

  While the processes in and after step S34 are repeated, the received power in the temporary frequency band may not be greater than the allocation determination threshold (step S35: No). In this case, and when the continuous number is larger than the threshold value for band determination (step S37: Yes), the switching unit 73 temporarily continues until this time and the received power is larger than the threshold value for allocation determination. A set of typical frequency bands is set as the frequency band of the second measuring unit 72 (step S38). And the relay station apparatus 71 complete | finishes the process which switches a 2nd frequency band.

  On the other hand, during the repetition of the processing from step S34, the received power in the temporary frequency band does not become larger than the threshold value for allocation determination (step S35: No), and the continuous number is larger than the threshold value for band determination. When there is not (step S37: No), the continuous number is reset (step S39), and the process proceeds to step S40. When the continuous number is reset in step S39, or when the continuous number is incremented in step S36, the comparison with the threshold for determination of assignment may be completed for all temporary frequency bands. (Step S40: Yes). In this case, the switching unit 73 compares the continuous number with a threshold for band determination (step S41).

  When the continuous number is larger than the threshold value for band determination (step S41: Yes), the switching unit 73 continues to this point in a temporary frequency band in which the received power is larger than the threshold value for allocation determination. The set is set as the frequency band of the second measuring unit 72 (step S42). On the other hand, when the continuous number is not larger than the threshold for band determination (step S41: No), the switching unit 73 sets the frequency band of the system as the frequency band of the second measuring unit 72 (step S43). . And the relay station apparatus 71 complete | finishes the process which switches a 2nd frequency band. The process of switching the second frequency band is performed when the relay station device 71 starts operation or periodically during operation. The process of estimating the received power of the reference signal and determining the amplification degree is the same as in the second embodiment.

  According to the fourth embodiment, the same effect as the second embodiment can be obtained. In addition, the second frequency band that is the measurement target of the received power can be switched according to the data signal allocation situation. The fourth embodiment may be applied when the second frequency band is divided more finely than the third embodiment. In addition, when the continuous number of temporary frequency bands in which the received power is larger than the threshold value for allocation determination does not become larger than the threshold value for band determination, the frequency band of the system excluding the first frequency band including the reference signal, That is, the frequency band Y may be set as the frequency band of the second measuring unit 72.

(Example 5)
FIG. 14 is a block diagram of an example of a wireless communication apparatus according to the fifth embodiment. The fifth embodiment is an example in which two power supply units are provided in the second embodiment. As illustrated in FIG. 14, the relay station device 81 includes a first power supply unit 82 and a second power supply unit 83 instead of the power supply unit 47 in the relay station device 31 of the second embodiment. In FIG. 14, the alternate long and short dash line represents the power supply line 84 connected to the first power supply unit 82, and the alternate long and two short dashes line represents the power supply line 85 connected to the second power supply unit 83.

  The first power supply unit 82 supplies the first measurement unit 44, the second measurement unit 45, the estimation unit 46, and the storage unit 48 with drive voltages that operate these units. The second power supply unit 83 is based on the estimation result of the received power of the reference signal by the estimation unit 46, the first amplification unit 40, the second amplification unit 41, the first adjustment unit 42, and the second adjustment unit. 43 is supplied with a driving voltage for operating these components. Other configurations are the same as those of the second embodiment.

FIG. 15 is a flowchart of an example of the wireless communication method according to the fifth embodiment. As shown in FIG. 15, when the process is started, first, the relay station device 81 operates the first power supply unit 82 (step S51). Thereby, a drive voltage is supplied to the first measurement unit 44, the second measurement unit 45, the estimation unit 46, and the storage unit 48, and these units operate.

  Next, the relay station device 81 estimates the received power of the reference signal by the estimation unit 46 in the same manner as in step S12 of the second embodiment (step S52). Next, the relay station device 81 uses the estimation unit 46 to compare the estimated value of the received power of the reference signal with the threshold value for operation determination (step S53). As a result of the comparison, if the estimated value of the received power of the reference signal is not smaller than the threshold for operation determination (step S53: No), the relay station apparatus 81 is not relayed and the process returns to step S52, and step S52 And the process of step S53 is repeated.

  When the estimated value of the received power of the reference signal is smaller than the threshold for operation determination (step S53: Yes), the relay station device 81 operates the second power supply unit 83 (step S54). Thereby, a driving voltage is supplied to the first amplifying unit 40, the second amplifying unit 41, the first adjusting unit 42, and the second adjusting unit 43, and these units operate. Next, the relay station device 81 determines the amplification degree in the same manner as in Step S14 and Step S15 of the second embodiment (Step S55, Step S56), and between the base station and the terminal station with the determined amplification degree. Starts relaying the signal. And it returns to step S52 and the relay station apparatus 81 implements operation | movement after step S52 periodically.

  According to the fifth embodiment, the same effect as in the second embodiment can be obtained. Further, when the relay operation is not performed, the supply of drive voltage to the amplification units 40 and 41 and the adjustment units 42 and 43 can be stopped, so that power consumption can be reduced.

(Example 6)
FIG. 16 is a block diagram of an example of a wireless communication apparatus according to the sixth embodiment. The sixth embodiment is an example in which the relay operation is not performed when there is no terminal station under the control in the fifth embodiment. As illustrated in FIG. 16, the relay station device 91 includes a third measurement unit 92 in addition to the configuration of the relay station device 81 of the fifth embodiment.

  The third measuring unit 92 measures the received power in the system frequency band for the uplink signal that has passed through the third filter unit 38. Alternatively, the third measuring unit 92 measures received power in a predetermined frequency band of the system frequency band for the uplink signal that has passed through the third filter unit 38. The estimation unit 46 determines whether there is a terminal station under control by comparing the received power measured by the third measurement unit 92 with a threshold for load determination. For example, the estimation unit 46 determines that there is a terminal station under control when the received power measured by the third measurement unit 92 is greater than the load determination threshold, and is measured by the third measurement unit 92. When the received power is not larger than the load determination threshold value, it may be determined that there is no terminal station under control.

  The storage unit 48 holds a threshold value for load determination. The threshold for load determination is set in advance. When the estimation unit 46 determines that there is a terminal station under the control, the second power supply unit 83 includes the first amplification unit 40, the second amplification unit 41, the first adjustment unit 42, and the second adjustment unit. A driving voltage for operating these units is supplied to the unit 43. Other configurations are the same as those of the fifth embodiment.

FIG. 17 is a flowchart of an example of the wireless communication method according to the sixth embodiment. As shown in FIG. 17, when the process is started, first, the relay station device 91 operates the first power supply unit 82 (step S61). Thereby, a drive voltage is supplied to the first measurement unit 44, the second measurement unit 45, the estimation unit 46, and the storage unit 48, and these units operate.

  Next, the relay station device 91 estimates the received power of the reference signal by the estimation unit 46 in the same manner as in step S12 of the second embodiment (step S62). The relay station apparatus 91 uses the third measuring unit 92 to measure the received power in the system frequency band for the uplink signal (step S63). The third measurement unit 92 may measure received power in a predetermined frequency band of the system frequency band for the uplink signal that has passed through the third filter unit 38. Next, the relay station device 91 uses the estimation unit 46 to compare the estimated value of the received power of the reference signal with the threshold for operation determination (step S64). As a result of the comparison, when the estimated value of the received power of the reference signal is not smaller than the threshold for operation determination (step S64: No), the relay station apparatus 91 is not relayed and the process returns to step S62, and step S62 To S64 are repeated.

  When the estimated value of the received power of the reference signal is smaller than the threshold for operation determination (step S64: Yes), the relay station device 91 uses the estimating unit 46 to measure the received power and the load measured by the third measuring unit 92. The threshold value for determination is compared (step S65). As a result of the comparison, when the received power measured by the third measuring unit 92 is not larger than the threshold for load determination (step S65: No), the relay station device 91 is not relayed and the process proceeds to step S62. Returning, the processing from step S62 to step S65 is repeated.

  When the received power measured by the third measurement unit 92 is larger than the threshold for load determination (step S65: Yes), the relay station device 91 operates the second power supply unit 83 (step S66). Thereby, a driving voltage is supplied to the first amplifying unit 40, the second amplifying unit 41, the first adjusting unit 42, and the second adjusting unit 43, and these units operate. Next, the relay station device 91 determines the amplification degree in the same manner as in step S14 and step S15 of the second embodiment (step S67, step S68), and between the base station and the terminal station with the determined amplification degree. Starts relaying the signal. And it returns to step S62 and the relay station apparatus 91 implements the operation | movement after step S62 periodically. As described above, when the received power measured by the third measuring unit 92 is not larger than the load determination threshold value, the process for determining the amplification degree is not performed. Therefore, the amplification degree is controlled based on both the estimated value of the received power of the reference signal and the received power measured by the third measuring unit 92. According to the sixth embodiment, the same effect as in the fifth embodiment can be obtained.

  With respect to the above-described Examples 1, 2, 3, 4, 5, and 6, the following additional notes are disclosed.

(Supplementary Note 1) A first measurement unit that measures received power in a first frequency band of a downlink signal including a reference signal, and a second that measures received power in a second frequency band of the downlink signal And a estimator that estimates the received power of the reference signal based on the received power measured by the first measuring unit and the received power measured by the second measuring unit. A wireless communication device.

(Supplementary Note 2) The first frequency band includes the frequency of the reference signal, and the second frequency band is a system frequency band, and a frequency excluding the first frequency band of the system frequency band. The wireless communication apparatus according to appendix 1, wherein the wireless communication apparatus is any one of a band and an arbitrary part of a frequency band of the system.

(Supplementary note 3) Based on the reception state of the downlink signal, the second frequency band is a system frequency band, a frequency band excluding the first frequency band of the system frequency band, or the The wireless communication device according to attachment 2, further comprising a switching unit that dynamically switches between two or three of the frequency bands of the system.

(Supplementary note 4) An amplifying unit for amplifying the reception signal, and the operation of the amplification unit is controlled based on the reception power of the reference signal estimated by the estimation unit. The wireless communication device according to any one of the above.

(Supplementary note 5) The wireless communication device according to supplementary note 4, wherein the amplification degree of the amplification unit is controlled based on reception power of the reference signal estimated by the estimation unit.

(Supplementary note 6) The wireless communication apparatus according to any one of supplementary notes 1 to 3, further comprising a third measurement unit that measures reception power in a frequency band of an uplink signal.

(Supplementary note 7) The frequency band measured by the third measuring unit is either a system frequency band or an arbitrary part of the system frequency band. The wireless communication device according to appendix 6.

(Supplementary Note 8) An amplifying unit for amplifying a received signal, and the operation of the amplifying unit is the received power of the reference signal estimated by the estimating unit and the uplink measured by the third measuring unit The wireless communication apparatus according to appendix 6 or 7, wherein the radio communication apparatus is controlled based on the received power of the signal.

(Supplementary Note 9) The amplification degree of the amplification unit is controlled based on the reception power of the reference signal estimated by the estimation unit and the reception power of the uplink signal measured by the third measurement unit. The wireless communication apparatus according to appendix 8, wherein:

(Supplementary Note 10) A base station that transmits a downlink signal including a reference signal, a terminal station that receives a downlink signal transmitted from the base station, and relays the signal between the base station and the terminal station A first measurement unit that measures received power in a first frequency band of a downlink signal including the reference signal, and a second frequency of the downlink signal. A second measuring unit that measures the received power of the band; and the received power of the reference signal based on the received power measured by the first measuring unit and the received power measured by the second measuring unit. A wireless communication system comprising: an estimation unit for estimation.

(Supplementary Note 11) The first frequency band includes the frequency of the reference signal, and the second frequency band is a system frequency band, and a frequency excluding the first frequency band of the system frequency band. The wireless communication system according to appendix 10, wherein the wireless communication system is any one of a band or an arbitrary part of a frequency band of the system.

(Supplementary Note 12) A first measurement step of measuring the received power of the first frequency band of the downlink signal including the reference signal, and a second of measuring the received power of the second frequency band of the downlink signal And an estimation step for estimating the received power of the reference signal based on the received power measured in the first measuring step and the received power measured in the second measuring step. A wireless communication method characterized by the above.

(Supplementary Note 13) The first frequency band includes the frequency of the reference signal, and the second frequency band is a system frequency band, and a frequency excluding the first frequency band of the system frequency band. 13. The wireless communication method according to appendix 12, wherein the wireless communication method is any one of a band or an arbitrary part of a frequency band of the system.

DESCRIPTION OF SYMBOLS 1 Base station 2 Relay station 3, 4 Terminal station 11, 31, 61, 71, 81, 91 Relay station apparatus 12, 44 1st measurement part 13, 45, 62, 63, 72 2nd measurement part 14, 46 Estimator 22 Reference signal 64, 73 Switching unit 40, 41 Amplifying unit 92 Third measuring unit

Claims (5)

A first measurement unit that measures received power in a first frequency band of a downlink signal including a reference signal;
A second measuring unit for measuring received power of the second frequency band of the downlink signal;
An estimation unit that estimates the reception power of the reference signal based on the reception power measured by the first measurement unit and the reception power measured by the second measurement unit;
A wireless communication apparatus comprising:   The first frequency band includes a frequency of the reference signal, and the second frequency band is a system frequency band, a frequency band excluding the first frequency band of the system frequency band, or the The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is any one of a part of frequency bands of a system.   Based on the reception state of the downlink signal, the second frequency band may be a system frequency band, a frequency band excluding the first frequency band of the system frequency band, or a frequency band of the system The wireless communication apparatus according to claim 2, further comprising: a switching unit that dynamically switches between two or three frequency bands of any one of the frequency bands. A base station that transmits a downlink signal including a reference signal, a terminal station that receives a downlink signal transmitted from the base station, and a relay station that relays the signal between the base station and the terminal station, With
The relay station measures a received power of a first frequency band of a downlink signal including the reference signal, and a received power of a second frequency band of the downlink signal. A second measurement unit; and an estimation unit that estimates the reception power of the reference signal based on the reception power measured by the first measurement unit and the reception power measured by the second measurement unit. A wireless communication system comprising: A first measurement step of measuring received power in a first frequency band of a downlink signal including a reference signal;
A second measurement step of measuring received power in a second frequency band of the downlink signal;
An estimation step for estimating the reception power of the reference signal based on the reception power measured in the first measurement step and the reception power measured in the second measurement step;
A wireless communication method comprising:

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