JP5156952B2 - Detection method and wireless device using the same - Google Patents

Description

  The present invention relates to a detection technique, and more particularly, to a detection method for detecting timing of a received signal and a radio apparatus using the detection method.

In a wireless communication system, when burst transmission / reception is performed, timing synchronization on the receiving side is important. For timing synchronization, a known signal such as a unique word is generally added to the transmission signal in advance. For example, the receiving side calculates the cross-correlation for each symbol of the unique word and the received signal and sequentially detects the absolute value, and the point of the maximum value where the correlation value exceeds a preset threshold is set as the synchronization timing. (For example, refer to Patent Document 1).
JP 7-250120 A

  When frequency selective fading occurs in a wireless communication system, reflected waves arrive in addition to direct waves. In this case, the correlation value includes a plurality of peaks so as to correspond to the direct wave and the reflected wave. When the peak with respect to the last reflected wave is the maximum value, the receiving side establishes timing synchronization with respect to the last reflected wave. As a result, forward reflected waves and direct waves are excluded from reception targets. For example, when an OFDM (Orthogonal Frequency Division Multiplexing) modulation method is employed in a wireless communication system, reception power increases and reception characteristics improve when a forward reflected wave or direct wave is included. There is also.

  The present invention has been made in view of such a situation, and an object thereof is to provide a communication technique for detecting a synchronization timing suitable for a propagation environment.

  In order to solve the above problems, a radio apparatus according to an aspect of the present invention is an input for inputting a multicarrier signal from a radio apparatus to be communicated and including a known signal in each subcarrier. , A multi-branch unit that branches the multi-carrier signal input at the input unit into a single unit, and a multi-carrier signal that is branched into a plurality of multi-branch signals at the branch unit. A plurality of correlation units for deriving a correlation value with each other, and integration for deriving a plurality of integration values by combining and integrating a part of the correlation values derived in each of the plurality of correlation units And the timing of the multicarrier signal by detecting feature points of a plurality of integrated values derived by the integrating unit. And a detector for detecting a. Each of the plurality of correlation units stores a known signal rotated by a different phase, and multiplies the subcarrier value of the multicarrier signal by the stored known signal when deriving the correlation value. Then, the integrating unit combines the correlation values from the correlating unit that stores the known signals whose phase rotation amounts are close to each other among the plurality of correlating units.

  Another embodiment of the present invention is a detection method. This method includes a step of inputting a multicarrier signal from a wireless device to be communicated and including a known signal in each subcarrier, and a plurality of input multicarrier signals as one unit. A step of branching, a step of deriving a correlation value between each multicarrier signal and a known signal in a correlator provided for each of the multicarrier signals branched into a plurality of branches, and a step of deriving in each of the plurality of correlators A step of deriving a plurality of integrated values by combining a part of the correlation values and changing the combination, and a timing for the multicarrier signal by detecting feature points of the derived plurality of integrated values Detecting a deviation of the distance. In the step of deriving the correlation value, each of the plurality of correlators stores a known signal rotated by a phase different from each other, and when deriving the correlation value, the value of the subcarrier of the multicarrier signal, The step of multiplying the stored known signal and deriving a plurality of integrated values combines the correlation values from the correlators storing the known signals whose phase rotation amounts are close to each other among the plurality of correlators.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, the synchronization timing suitable for the propagation environment can be detected.

  Before describing the present invention specifically, an outline will be given first. Embodiments of the present invention relate to a communication system including a base station device and a terminal device. The communication system employs an OFDMA (Orthogonal Frequency Division Multiple Access) scheme, and a plurality of subchannels are defined on the frequency axis and a plurality of time slots are defined on the time axis. Moreover, the communication between the terminal device and the base station device is realized by assigning the combination of the subchannel and the time slot to the terminal device as a burst. In such an OFDMA system, the frequency and timing of a signal transmitted from a terminal apparatus are required to be synchronized with those in a base station apparatus.

  Note that, when there is a shift in these synchronizations, the base station apparatus instructs the terminal apparatus to correct the shift. Here, a description will be given focusing on a part where the base station apparatus receives a signal from the terminal apparatus and detects a timing shift. In order to detect the timing, as described above, the maximum value of the correlation value is generally detected. When a delayed wave is also present due to frequency selective fading, the correlation value may be maximized at a non-optimal timing. As a result, a non-optimal timing is determined as the synchronization timing. In order to cope with this, the communication system according to the present embodiment executes the following processing.

  A signal from the terminal device, that is, a signal arranged in a burst constitutes a packet signal, and a known signal is arranged at the head portion of the packet signal. The known signal is associated with each subcarrier. The base station apparatus stores a plurality of combinations of known signals over a plurality of subcarriers. The plurality of combinations have different amounts of phase rotation. For example, the first combination corresponds to the known signal itself, and phase rotation is performed on the first combination from the second combination to the fourth combination. Such phase rotation corresponds to a timing shift.

  The base station apparatus branches the received packet signal into a plurality of frequencies after converting the received packet signal into the frequency domain by FFT. Further, the base station apparatus calculates a correlation value between each branched packet signal and the known signal. At this time, the combination of known signals is changed for each packet signal. Further, the base station device derives an integrated value for a part of the plurality of correlation values. A plurality of integrated values are derived while changing the combination. Here, the combination of correlation values is determined so that the amount of phase rotation with respect to the known signal is close. Therefore, such integration corresponds to an average value of correlation values in the frequency domain. The base station apparatus detects the peak of the integrated value, and detects a timing shift from the phase rotation amount corresponding to the peak.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. The communication system 100 includes a terminal device 10, a base station device 12, and a network 14. The terminal device 10 is a wireless device that supports a predetermined wireless system. As a wireless system, for example, an OFDMA system is assumed. In the OFDMA scheme, a plurality of subchannels are multiplexed on the frequency axis, and each subchannel is configured by an OFDM signal. Here, the terminal device 10 has a call function and a data communication function. Data communication is, for example, transmission / reception of electronic mail, browsing of the World Wide Web (WWW), execution of VoIP (Voice over Internet Protocol), and these processes may be performed by the terminal device 10 alone, You may make by connection with PC which is not illustrated.

  The base station device 12 is connected to the terminal device 10 by wireless communication at one end and connected to the network 14 by wired communication at the other end. As described above, the base station apparatus 12 defines a plurality of subchannels and a plurality of time slots, and assigns the combination to the terminal apparatus 10 as a burst. Also, the base station apparatus 12 assigns the downlink burst and the uplink burst to the terminal apparatus 10 as one combination. For example, the terminal apparatus 10 transmits a burst allocation request to the base station apparatus 12, and the base station apparatus 12 allocates a burst to the terminal apparatus 10 and notifies the terminal apparatus 10 of the result. Here, since the OFDMA scheme is adopted, the terminal apparatus 10 and the base station apparatus 12 may perform the ranging process before and after transmission of the burst allocation request. In addition, since a well-known technique should just be used as a ranging process, description is abbreviate | omitted here.

  Even after the end of the ranging process, the terminal apparatus 10 performs control so as to be synchronized with the operation timing in the base station apparatus 12 and the frequency of the carrier wave. Specifically, when receiving a signal from the terminal device 10, the base station device 12 detects a frequency offset and a timing shift included therein, and instructs the terminal device 10 to correct them. Here, the description will focus on the detection of timing deviation, which will be described later. The network 14 is also connected to a communication device (not shown). For example, the network 16 is configured by an IP (Internet Protocol) network, but is not limited thereto. The network 16 transmits the data received from the communication device to the base station device 12, and transmits the data received from the base station device 12 to the communication device.

  2A to 2C show a frame configuration in the communication system 100. FIG. The horizontal direction in the figure corresponds to the time axis. The frame is formed by 8 time slots. The eight time slots are composed of four upstream time slots and four downstream time slots. Here, four uplink time slots are indicated as “first uplink time slot” to “fourth uplink time slot”, and four downlink time slots are indicated as “first downlink time slot” to “fourth downlink time slot”. . Further, the illustrated frame is repeated continuously. Note that the configuration of the frame is not limited to FIG. 2A, but here, for the sake of clarity, the configuration of the frame will be described as FIG. Further, in order to simplify the description, only one of the uplink time slot and the downlink time slot may be described, but the same description is valid for the other time slot.

  FIG. 2B shows the configuration of one time slot in FIG. The vertical direction in the figure corresponds to the frequency axis. As shown in the figure, one time slot is formed by “16” subchannels from “first subchannel” to “16th subchannel”. In addition, the plurality of subchannels are frequency division multiplexed. Since each time slot is configured as shown in FIG. 2B, a burst is specified by a combination of a time slot and a subchannel. By assigning the identified burst to the terminal apparatus 10, the terminal apparatus 10 and the base station apparatus 12 perform communication. Also, the frame configuration corresponding to one subchannel in FIG. 2B may be as shown in FIG.

  FIG. 2 (c) shows the configuration of one subchannel in FIG. 2 (b). Note that the subchannel is formed by the OFDM signal as described above. Similar to FIG. 2A and FIG. 2B, the horizontal direction in the figure corresponds to the time axis, and the vertical direction in the figure corresponds to the frequency axis. Further, numbers “1” to “29” are assigned to the frequency axis, and these indicate subcarrier numbers. In this way, the subchannel is composed of multicarrier signals, and in particular is composed of OFDM signals. “TS” in the figure corresponds to a training symbol and is constituted by a known value. Further, it is assumed that a control signal may be included in “TS”. “GS” corresponds to a guard symbol, and no substantial signal is arranged here. “PS” corresponds to a pilot symbol, and is configured by a known value. “DS” corresponds to a data symbol and is data to be transmitted. “GT” corresponds to a guard time, and no substantial signal is arranged here.

  FIG. 3 shows an arrangement of subchannels in the communication system 100. In FIG. 3, the frequency axis is shown on the horizontal axis, and the spectrum for the time slot shown in FIG. 2B is shown. As described above, 16 subchannels from the first subchannel to the 16th subchannel are frequency division multiplexed in one time slot. As described above, each subchannel is composed of a multicarrier signal, here, an OFDM signal.

  FIG. 4 shows the configuration of the base station apparatus 12. The base station apparatus 12 includes a radio unit 20, a modem unit 22, an IF unit 24, and a control unit 26, and the modem unit 22 includes a modulation unit 28 and a demodulation unit 30. As a reception process, the radio unit 20 performs frequency conversion and quadrature detection on a radio frequency signal received from a terminal device 10 (not shown) to generate a baseband signal. Further, the radio unit 20 outputs a baseband signal to the demodulation unit 30. In general, baseband signals are formed by in-phase and quadrature components, so they should be transmitted by two signal lines. Here, for clarity of illustration, only one signal line is used. Shall be shown. The radio unit 20 also includes an AGC.

  As a transmission process, the radio unit 20 performs orthogonal modulation and frequency conversion on the baseband signal input from the modulation unit 28 to generate a radio frequency signal. Further, the radio unit 20 transmits a radio frequency signal. The radio unit 20 transmits a signal while using the same radio frequency band as the received signal. That is, it is assumed that TDD is used as shown in FIG. The wireless unit 20 also includes a PA (Power Amplifier).

  Modulator 28 modulates the data received from IF unit 24. For example, 16QAM (Quadrature Amplitude Modulation), QPSK (Quadrature Phase Shift Keying), or the like is used as the modulation method. Also, the modulation unit 28 receives an instruction regarding a downlink burst from the demodulation unit 30 and allocates the modulated data to the burst. As a result, a multi-carrier signal in the frequency domain, particularly an OFDM signal is generated. Note that the OFDM signal may include a plurality of subchannels. Thereafter, the modulation unit 28 generates an OFDM signal in the time domain by performing IFFT on the OFDM signal in the frequency domain. Further, the modulation unit 28 outputs the OFDM signal in the time domain to the radio unit 20 as the baseband signal described above.

  The demodulator 30 receives a baseband signal from the radio unit 20. Since the received baseband signal corresponds to a time-domain OFDM signal, the demodulator 30 performs an FFT on the time-domain OFDM signal to generate a frequency-domain OFDM signal. The demodulator 30 demodulates the frequency domain OFDM signal. The demodulation corresponds to the modulation performed in the terminal device 10 (not shown). Further, the demodulator 30 outputs the demodulated data as another packet signal for each terminal device 10 that is a transmission source. Note that an instruction regarding the terminal device 10 serving as a transmission source is received from the control unit 26. When the communication system 100 performs error correction, the modulation unit 28 may perform encoding and the demodulation unit 30 may perform decoding.

  Further, in parallel with the above processing, the demodulator 30 detects a timing shift with respect to the packet signal based on the packet signal received from the terminal device 10. Such a timing shift can also be said to be a timing shift in the terminal device 10. Note that detection of timing deviation will be described later. The demodulator 30 outputs the detected timing shift to the controller 26. The IF unit 24 receives data addressed to the terminal device 10 from the network 14 (not shown), and outputs the received data to the modulation unit 28. The IF unit 24 receives data from the terminal device 10 and outputs the received data to the network 14. Here, the data is formed by packet signals.

  The control unit 26 controls the operation of the base station apparatus 12. The control unit 26 also assigns bursts to the terminal device 10. The control unit 26 receives an allocation request from the terminal device 10 from the radio unit 20 via the IF unit 24. The control unit 26 executes allocation processing for the terminal device 10 that has received the allocation request. That is, the control unit 26 assigns bursts to the terminal device 10. Further, since OFDMA is adopted as a communication method, the control unit 26 performs a ranging process on the terminal device 10. The control unit 26 notifies the result assigned to the terminal device 10 from the IF unit 24 via the wireless unit 20. Further, when receiving a timing shift amount from the demodulation unit 30 during communication, the control unit 26 instructs the terminal device 10 to correct the shift amount from the IF unit 24 via the wireless unit 20. For example, when the deviation amount is “T”, the control unit 26 instructs correction by “−T”. Such an instruction is included in a packet signal from the base station apparatus 12 to the terminal apparatus 10.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 5 shows the configuration of the demodulator 30. The demodulation unit 30 includes an FFT unit 50, a synchronous detection unit 52, a decoding unit 54, a branching unit 56, a first correlation unit 58a, a second correlation unit 58b, an Nth correlation unit 58n, and an integration unit 60. , Including a detection unit 62.

  The FFT unit 50 receives an OFDM signal from a terminal device 10 (not shown). The received OFDM signal corresponds to an OFDM signal in the time domain. Here, the OFDM signal is composed of packet signals as shown in FIGS. Further, as shown in FIG. 2C, in the packet signal, a known signal such as “TS” is included in each subcarrier. The FFT unit 50 generates a frequency domain OFDM signal by performing FFT on the time domain OFDM signal. An OFDM signal in the frequency domain is composed of a plurality of subcarriers. Here, for the sake of clarity, the OFDM signal in the frequency domain is indicated by one signal line. The FFT unit 50 outputs the frequency domain OFDM signal to the synchronous detection unit 52 and the decoding unit 54.

  The synchronous detection unit 52 receives the OFDM signal in the frequency domain from the FFT unit 50, and estimates the transmission path characteristic in subcarrier units in the “TS” portion. The synchronous detector 52 demodulates the OFDM signal in the frequency domain in units of subcarriers based on the estimated transmission path characteristics. The synchronous detection unit 52 outputs the demodulated signal to the decoding unit 54. The decoding unit 54 receives the demodulated signal from the synchronous detection unit 52 and performs decoding on the demodulated signal. Decoding corresponds to encoding performed in the terminal device 10 (not shown). For example, when convolutional encoding is performed as encoding, the decoding unit 54 performs Viterbi decoding. The decoding unit 54 outputs the decoded signal.

  The branching unit 56 receives the frequency domain OFDM signal from the FFT unit 50 and branches the frequency domain OFDM signal into a plurality of parts. The number of branches is determined according to the number of correlation units 58 described later. Further, as described above, the OFDM signal in the frequency domain includes a plurality of subcarriers, but the branching unit 56 branches the plurality of subcarriers into a plurality of groups. The branching unit 56 outputs a plurality of branched OFDM signals in parallel.

ここで、Ｃは、定数であり、Δｔは、予め定められた値である。なお、Δｔは、すべてのサブキャリアについて共通の値となるように定められている。 A plurality of correlation units 58 are provided for each of the OFDM signals branched into a plurality of branches 56. First correlator 58a stores the value of “TS” in units of subcarriers in advance. On the other hand, the second correlator 58b stores in advance a value obtained by rotating the value of “TS” by a fixed phase in units of subcarriers. For example, if the values of “TS” for the kth subcarrier are I (k) and Q (k), the values I ′ (k) and Q for the kth subcarrier stored in the second correlator 58b '(K) is shown as follows.

Here, C is a constant, and Δt is a predetermined value. Note that Δt is determined to be a common value for all subcarriers.

  Similarly to the second correlation unit 58b, the third correlation unit 58c to the N-th correlation unit 58n store in advance a value obtained by rotating the value of “TS” by a certain phase in units of subcarriers. However, in the second correlation unit 58b to the Nth correlation unit 58n, the value of Δt is different from each other, and the value of Δt increases as the second correlation unit 58b changes to the Nth correlation unit 58n. That is, each of the plurality of correlation units 58 stores a value of “TS” rotated by different phases. Such Δt corresponds to a timing shift, and it can be said that the correlator 58 stores “TS” values corresponding to different timings.

  Each of the plurality of correlation units 58 derives a correlation value between the frequency domain OFDM signal and the stored value. More specifically, the correlation unit 58 multiplies the frequency-domain OFDM signal and the stored value in units of subcarriers, and accumulates the multiplication results. As described above, the timing of the TS stored in each correlator 58 is different, so the timing corresponding to the correlation value derived in each correlator 58 is also different. The correlation unit 58 outputs the correlation value to the integration unit 60.

  The integrating unit 60 receives a correlation value from each of the plurality of correlation units 58. The integrating unit 60 combines and integrates some of the plurality of correlation values. For example, the integration unit 60 integrates the correlation values from the first correlation unit 58a to the third correlation unit 58c. That is, the integrating unit 60 combines the correlation values from the correlating unit 58 that stores “TS” whose phase rotation amounts are close to each other among the plurality of correlating units 58. Further, the integrating unit 60 derives a plurality of integrated values by changing the combination. For example, the integration unit 60 derives an integration value for the correlation value from the second correlation unit 58b to the fourth correlation unit 58d, an integration value for the correlation value from the third correlation unit 58c to the fifth correlation unit 58e, and the like. Here, in association with the stored timing shift amount of “TS”, the first correlator 58a is defined as the front, and the Nth correlator 58n is defined as the rear. In that case, the integrating unit 60 derives a plurality of integrated values by shifting the range of integration from the front to the back. Note that the range of integration may be determined in advance.

  The detection unit 62 detects a timing shift with respect to the OFDM signal by detecting feature points of a plurality of integration values derived by the integration unit 60, for example, maximum values. FIG. 6 shows an outline of processing in the demodulator 30. The horizontal axis corresponds to the shift amount of “TS” stored in the correlation unit 58. The vertical axis corresponds to the correlation value for the dotted line and the integrated value for the solid line. That is, with respect to the dotted line, the left side corresponds to the correlation value derived by the first correlation unit 58a, and the right side corresponds to the correlation value derived by the Nth correlation unit 58n. As shown in the figure, the second correlation value and the fourth correlation value from the left increase. When the maximum correlation value is detected by the detection unit 62, the fourth correlation value is detected here.

  When an instruction is given to the terminal device 10 so as to correct the timing shift corresponding to the fourth correlation value, the influence of the direct wave or delayed wave corresponding to the second correlation value is reduced. As a result, the received power is reduced, and there is a possibility that the optimum characteristics may not be obtained. On the other hand, since the detection unit 62 detects the maximum value of the plurality of integrated values derived by the integrating unit 60, the second integrated value from the left is detected here. As a result, the influence of the direct wave or the delayed wave corresponding to the second correlation value is increased, and the influence of the delayed wave corresponding to the fourth correlation value is also increased. Returning to FIG.

  Note that the detection unit 62 associates the range of integration of the integration values in the integration unit 60 with the amount of timing deviation in advance. The detection unit 62 specifies the amount of timing deviation from the range of integration corresponding to the maximum integrated value. The detection unit 62 notifies the control unit 26 (not shown) of the identified timing shift amount. The control unit 26 notifies the terminal device 10 of the timing shift amount from the IF unit 24 (not shown) to the terminal device 10 via the wireless unit 20. Alternatively, the control unit 26 may instruct to correct the timing shift amount. For example, when the timing shift amount is “T”, the control unit 26 instructs the terminal device 10 to correct the timing by “−T”.

  According to the embodiment of the present invention, since the integrated value of the correlation values with different timings is derived, the influence of the direct wave and the delayed wave can be smoothed. Moreover, since the timing shift is specified based on the integrated value, it is possible to reduce the specification to a timing that excludes a necessary direct wave or delayed wave. In addition, since it is possible to reduce the timing to exclude the necessary direct wave and delayed wave, it is possible to suppress a decrease in timing identification accuracy due to the influence of the propagation environment. In addition, since a decrease in timing identification accuracy is suppressed, a synchronization timing suitable for the propagation environment can be detected. In addition, since it is configured by correlation processing and integration processing, a simple configuration can be realized. Further, since the integration is executed in the frequency domain, the processing can be executed in parallel.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the radio scheme between the base station apparatus 12 and the terminal apparatus 10 is OFDMA. However, the present invention is not limited to this, and the wireless system may be other than OFDMA, for example. In that case, the ranging process between the terminal apparatus 10 and the base station apparatus 12 is omitted. According to this modification, the present invention can be applied to various wireless systems.

  In the embodiment of the present invention, the integration unit 60 predetermines the range of integration. However, the present invention is not limited to this. For example, the integrating unit 60 may adaptively change the range of integration. Specifically, as described above, the detection unit 62 detects the maximum value of the integrated value and specifies the correlation value included in the detected integrated value. For example, the detection unit 62 specifies the maximum value among a plurality of correlation values included in the integrated value. The detection unit 62 also specifies a correlation value from the correlation unit 58 that stores a TS whose phase rotation amount is smaller than the specified correlation value and is larger than the threshold value. Based on the two correlation values specified by the detection unit 62, the integration unit 60 determines an integration range, that is, the number of correlation values to be combined. For example, the range of integration is determined so that two correlation values are included. The range of integration determined in this way is used when the next and subsequent packet signals are received. According to this modification, the range of integration is adaptively changed, so that the range of integration suitable for the propagation environment can be set.

  In the embodiment of the present invention, the integration unit 60 integrates a plurality of correlation values. However, the present invention is not limited to this. For example, the integration unit 60 may perform integration while multiplying each of a plurality of correlation values by a weighting coefficient. At this time, the integrating unit 60 stores a known signal having a smaller phase rotation amount than the weighting factor for the correlation value from the correlation unit 58 that stores a known signal having a larger phase rotation amount among the plurality of correlation units 58. The weighting coefficient for the correlation value from the correlation unit 58 is increased. According to this modification, since the detected timing is ahead, the number of affected direct waves and delayed waves increases, and the received power can be improved.

  In the embodiment of the present invention, timing detection processing by the branching unit 56 to the detection unit 62 is performed when communication with the terminal device 10 is being executed. However, the present invention is not limited to this. For example, the timing detection process may be executed during the ranging process. According to this modification, the present invention can be used in various situations.

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the frame structure in the communication system of FIG. It is a figure which shows the frame structure in the communication system of FIG. It is a figure which shows the frame structure in the communication system of FIG. It is a figure which shows arrangement | positioning of the subchannel in the communication system of FIG. It is a figure which shows the structure of the base station apparatus of FIG. It is a figure which shows the structure of the demodulation part of FIG. It is a figure which shows the outline | summary of the process in the demodulation part of FIG.

Explanation of symbols

  10 terminal devices, 12 base station devices, 14 networks, 20 radio units, 22 modem units, 24 IF units, 26 control units, 28 modulation units, 30 demodulation units, 50 FFT units, 52 synchronous detection units, 54 decoding units, 56 Branching unit, 58 correlation unit, 60 integrating unit, 62 detecting unit, 100 communication system.

Claims (5)

An input unit for inputting a multicarrier signal from a wireless device to be communicated and including a known signal in each subcarrier;
A branching unit that branches the multicarrier signal input at the input unit into a plurality of groups,
The correlation unit is provided for each of the multi-carrier signal split into a plurality in the bifurcation, and the correlation of each, the value of the subcarrier of each multi-carrier signal, only the phase which differs from each other for storing A plurality of correlation units for deriving a correlation value by multiplying the rotated known signal;
An integration unit that integrates and integrates the correlation values derived in the correlation unit that stores known signals whose phase rotation amounts are close to each other among the plurality of correlation units, and derives a plurality of integration values by changing the combination; ,
Wherein by detecting a feature point of a plurality of integrated values derived in the integration unit, the wireless device characterized by obtaining Bei and a detector for detecting a deviation of the timing for the multi-carrier signal. The detecting unit detects a peak of the integrated value as a feature point of the integrated value, and specifies a combination in the integrating unit corresponding to the peak of the integrated value, and a correlation value included in the specified combination And means for specifying a correlation value corresponding to a known signal having a smaller amount of phase rotation than the correlation value and greater than a threshold value,
The radio apparatus according to claim 1, wherein the integration unit determines the number of correlation values to be combined based on the two correlation values specified by the detection unit.   The integration unit performs integration while multiplying each of a plurality of correlation values by a weighting coefficient, and a correlation value from a correlation unit that stores a known signal having a large amount of phase rotation among the plurality of correlation units. 3. The radio apparatus according to claim 1, wherein a weighting factor for a correlation value from a correlation unit storing a known signal having a smaller amount of phase rotation than a weighting factor for is increased.   The wireless device according to claim 1, further comprising a notification unit that notifies the communication target wireless device of a timing difference detected by the detection unit. A multicarrier signal from a wireless device to be communicated, and a multicarrier signal including a known signal included in each subcarrier; and
A step of branching the input multi-carrier signal into a single unit,
In the correlator provided for each of the multicarrier signals branched into a plurality, the value of the subcarrier of each multicarrier signal is multiplied by the known signal rotated by a different phase stored in each correlator. And deriving a correlation value,
A step of deriving a plurality of integrated values by combining and integrating the correlation values derived in the correlator storing the known signals whose phase rotation amounts are close to each other among the plurality of correlators; and
By detecting the feature points of the derived plurality of integrated values, the detection method characterized by obtaining Bei detecting a deviation of the timing for the multi-carrier signal.

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