JP2010258503A - Tdd type wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when the reception-side speed of a TDD type wireless communication device is slow, a delay for correcting variations of an antenna peripheral circuit can not be measured with high precision. <P>SOLUTION: In the TDD type wireless communication device which performs conversion between a digital main signal input from a host device and an analog transmission and reception signal with an intermediate frequency between the frequency of the digital main signal and a carrier frequency, a timing control unit 12 which varies a delay time of a calibration signal for measuring delay times of antenna peripheral circuits 30, 31 in a no-signal section of a time-division switching part between a transmission time and a reception time is provided on a transmission side. Each of the antenna peripheral circuits returns a transmission calibration signal to a reception side. A correlator 25 calculates correlation between the transmission calibration signal and the returned calibration signal. A transmission delay adjustment unit 13 and a reception delay adjustment unit 22 adjust a delay of the digital signal with the intermediate frequency based upon a result of the correlation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a TDD (Time Division Duplex) digital wireless communication system, and more particularly to a delay correction circuit in a TDD wireless communication apparatus.

  In a TDD wireless communication apparatus, an adaptive array antenna composed of a plurality of antennas is often used as a countermeasure against interference between other stations when a plurality of stations communicate simultaneously in the same band. In this case, since the antenna peripheral circuit corresponding to each antenna is composed of analog elements, there is a large variation in the delay amount. Therefore, it is necessary to measure the delay amount in order to correct it. This measurement is called delay calibration.

  Conventionally, calibration in a TDD wireless communication apparatus that uses the same frequency for transmission and reception is performed at a fixed timing from the transmission side using a gap that is a no-signal section of a time division switching portion between transmission time and reception time. Transmission of test signals (test signals). The receiving side receives the calibration signal turned back in its own station, and detects the correlation with the transmission calibration signal while changing the circuit delay amount.

  FIG. 7 shows a TDD wireless communication apparatus in which the above prior art is drawn so as to facilitate comparison with the present invention. This wireless communication device includes a DUC (Digital Up Converter) 42 that multiplies the speed of data input from a host device (not shown) to an intermediate frequency, and a DDC (Digital Down Converter) 53 that multiplies the carrier frequency to an intermediate frequency. Is used. A code generator 41 for generating a calibration signal is inserted in the main signal flow path.

  In FIG. 7, a calibration signal is transmitted at a fixed timing from the code generation unit 41 on the transmission side (upper part of the figure), and is returned to the reception side (lower part of the figure) via the antenna sharing control unit 30 and the coupler 31. The timing control unit 54 on the reception side performs timing control so as to change the delay amount for this calibration signal. The correlator 56 measures the delay amount of the antenna peripheral circuit (the antenna sharing control unit 30 and the coupler 31) by correlating the calibration signal on the transmission side with the timing-controlled calibration signal.

  However, in this configuration, since the input data rate of the correlator 56 is limited to the output of the DDC 53, that is, the reception data rate (reception data sampling period), a high-accuracy delay is achieved when the reception side is slow. There is a problem that it cannot be measured. In addition, when the timing control unit 54 is moved to the transmission side (immediately before the DUC) in this configuration, the main signal transmission is adversely affected.

  A technique is also known in which a timing control circuit 54 is provided on the transmission side, a calibration signal is transmitted at a speed obtained by multiplying the reference frequency, and a delay time until reception on the transmission side and the reception side is measured. However, this technique has no concept of correlating the transmission side and the reception side, and measures the delay time until the calibration signal returns from the transmission side to the reception side, as if it is timed by a stopwatch. Even when the calibration signal is transmitted at a high speed on the transmission side, there is a problem that high-precision measurement cannot be performed if the reception side is slow.

Japanese Unexamined Patent Publication No. 2000-013454 Japanese Patent No. 3180735

  The problem to be solved is that when the speed on the receiving side is slow, the delay amount for correcting variations in the antenna peripheral circuit cannot be measured with high accuracy.

  The main feature of the present invention is that a timing control unit for changing the delay amount of the calibration signal is provided in a portion where the sampling rate on the transmission side is high, and the calibration signal is inserted into the path of the main signal.

  The TDD wireless communication apparatus of the present invention has a first advantage that it can detect a delay amount with higher accuracy than the data rate on the receiving side. The reason for this is that a timing control circuit that is faster than the received data rate is provided on the transmission side, and timing control is performed in units of higher speeds after the speed conversion on the transmitting side, so that a higher unit in finer units than the received data rate. This is because an accurate delay amount can be obtained from the calculation result of the correlation value.

  Further, there is a second advantage that delay measurement is possible even during operation because the insertion timing of only the calibration signal is controlled.

The block diagram which shows one Example of the TDD system radio | wireless communication apparatus of this invention Diagram for explaining the operation of the timing controller Diagram showing calibration signal held by code generator The figure which shows the calibration signal which is inserted with delay in the timing control section Diagram showing Decimation at DDC The figure which shows the calculation result of correlation value in correlator Block diagram showing a conventional TDD wireless communication apparatus

  FIG. 1 is a block diagram showing an embodiment of the present invention. This TDD wireless communication apparatus corrects the amount of delay due to the occurrence of variations caused by changes in the antenna peripheral circuit over time, the environmental temperature of the apparatus, the transmission frequency, and the like. In FIG. 1, the transmission side transmits a digital data transmission unit 10 that transmits digital data input from a host device, a DUC 11 that converts the speed of the digital data, a timing control unit 12 that performs timing control, and a transmission calibration result. A transmission delay adjusting unit 13 to reflect, a DAC (Digital To Analog Converter) 14 for converting a digital signal into an analog signal, a wireless transmission unit 15 for frequency conversion to a carrier frequency, and a code generation unit 16 for generating a calibration signal .

  The reception side also includes a wireless reception unit 20 that processes received data, an ADC (Analog To Digital Converter) 21 that converts an analog signal into a digital signal, a reception delay adjustment unit 22 that reflects a reception calibration result, and a reception speed. It comprises a DDC 23 for conversion, a digital data receiver 24 for receiving digital data, and a correlator 25 for performing correlation calculation.

  The output terminal 17 on the transmission side and the input terminal 26 on the reception side are connected to the terminals a and c of the antenna sharing control unit 30, and the terminals b and d of the antenna sharing control unit 30 are connected to two terminals of the coupler 31. . One end of the coupler 31 connected to the terminal b is led to the antenna 32, and the other end of the coupler 31 is connected to the terminal d.

  The speed of data input from the host device is 5 MHz, the carrier frequency is 2 GHz for both transmission and reception, and the intermediate speed is 80 MHz. The intermediate speed is determined in consideration of the operation speed and circuit configuration required for the transmission-side circuits 11 to 14 and the reception-side circuits 21 to 23. Each element 10-16, 20-25, 30 shown in FIG. 1 operate | moves by the control signal from a high-order apparatus.

  The DUC 11 has a built-in 16-times Interpolation circuit, and multiplies the data rate 5 MHz input from the host device to 80 MHz. The code generator 16 holds a calibration signal of 5 MHz shown in FIG. 3A and an calibration signal of 80 MHz shown in FIG. 3B. The former is the correlator 25 and the latter is the timing controller 12. Output to. In FIG. 3, the values indicated by the black dots are meaningful, and the solid line connecting them is only an auxiliary line. In FIG. 3B, the time interval between the black spots is 1/80 MHz.

  The timing control unit 12 inserts the 80 MHz calibration signal held by the code generation unit 16 into the no-signal interval between the transmission time and the reception time while delaying in units of 1/80 MHz as shown in FIG. . The value of k in FIG. 4 is a value sufficient to measure the delay. The delay amount when N = k is k / 80 MHz. The transmission delay adjusting unit 13 delays the main signal so as to reflect the calibration result of the transmission path. The output of the DAC 14 is 80 MHz, and this is up-converted to a carrier frequency of 2 GHz by the wireless transmission unit 15 and output from the transmission terminal 17.

  The antenna sharing control unit 30 exchanges main signals with the antenna 32. At the time of transmission of the main signal, the terminal a and the terminal b are directly connected as shown in FIG. 2 (A), and at the time of reception, the terminal b and the terminal c are directly connected as shown in FIG. 2 (B). Further, at the time of transmission path delay measurement, terminal a and terminal b and terminal c and terminal d are directly connected as shown in FIG. 2 (C), and at the time of reception path delay measurement, terminal a and terminal a as shown in FIG. 2 (D). Terminals d, b and c are directly connected.

  The main signal input from the reception terminal 26 has a carrier frequency of 2 GHz, and is down-converted to 80 MHz by the radio reception unit 20. The output of the ADC 21 is 80 MHz, and the transmission delay adjustment unit 22 delays the main signal to reflect the calibration result of the reception path.

  The DDC 23 incorporates a 1/16 Decimation circuit and down-converts 80 MHz input data to 5 MHz. FIG. 5 shows how the detection level of the signal sampled by the DDC 23 changes when the delay amount is changed by the timing control unit 12. This result is output to the correlator 25.

The correlator 25 calculates a correlation value between the reception data Rx (m), which is the output of the DDC 23, and the 5 MHz calibration signal Tx (m) held by the code generator 16 by the following equation. P represents the number of calibration signals.

  FIG. 6 graphically displays the correlation value when the delay amount N of the calibration signal is changed. The value of the delay amount k that gives the vertex of the graph with the maximum correlation value is the delay amount of this system. The connection in the antenna sharing control unit 30 is switched as shown in FIGS. 2C and 2D, and such correlation is obtained for the transmission path and the reception path. The correlation result obtained by the correlator 25 is output to the host device. The host device outputs a control signal for instructing the delay to the transmission delay adjustment unit 13 and the reception delay adjustment unit 22 from the correlation result.

  The main signal input from the host device is transmitted from the antenna 32 via the digital data transmission unit 10 to the wireless transmission unit 15, the antenna sharing control unit 30 and the coupler 31. At this time, there is no timing control in the timing control unit 12, and the transmission delay adjustment unit 13 adjusts the delay of the main signal by the control signal from the host device. The control signal is based on the transmission path delay measurement obtained by the connection shown in FIG. Further, the connection between the terminals in the antenna sharing control unit 30 is as shown in FIG.

  The main signal received by the antenna 32 is sent to the host device via the coupler 31, the antenna sharing control unit 30, and the radio reception unit 20 to the digital data reception unit 24. At this time, the connection between the terminals in the antenna sharing control unit 30 is as shown in FIG. The reception delay adjusting unit 22 adjusts the delay of the main signal by a control signal from the host device. The control signal is based on the delay measurement of the reception path obtained by the connection shown in FIG. The correlation as described above is obtained by using the gap which is a non-signal section of the time division switching portion between the transmission time and the reception time of the main signal.

  The following various embodiments are conceivable for the wireless communication apparatus having the basic configuration so far. First, in order to obtain a multi-carrier configuration, a plurality of X sets of digital data transmission unit 10, DUC 11, timing control unit 12, code generation unit 16, and transmission delay adjustment unit 13 that transmit main signals of different carrier frequencies are connected in parallel. A processing unit that bundles the carrier frequencies of the transmission signals so as not to overlap on the frequency axis is provided in the front stage of the DAC 14. In addition, a plurality of X sets of the reception delay adjusting unit 22, DDC 23, digital data receiving unit 24, and correlator 25 are connected in parallel, and a processing unit for separating the multiplexed received signals is provided in the subsequent stage of the ADC 21. With this configuration, it is possible to obtain the same effect as the above-described basic configuration for each of the X circuit groups.

  Next, although the single antenna 32 is used in the basic configuration, a multi-channel configuration in which a plurality of antennas and an antenna sharing control unit are provided may be used. In this case, the delay amount is measured in order to correct the variation of the antenna peripheral circuit along with the aging of the antenna peripheral circuit. This multi-channel configuration may be combined with the multi-carrier configuration.

10 Digital data transmitter 11 DUC
12 Timing control unit 13 Transmission delay adjustment unit 14 DAC
DESCRIPTION OF SYMBOLS 15 Wireless transmission part 16 Code generation part 17 Transmission terminal 20 Wireless reception part 21 ADC
22 Reception delay adjustment unit 23 DDC
24 digital data receiving unit 25 correlator 26 receiving terminal 30 antenna sharing control unit 31 coupler 32 antenna unit a to d terminals

Claims (4)

In a TDD wireless communication apparatus that performs conversion between the digital main signal and the analog transmission / reception signal at an intermediate frequency between the frequency of the digital main signal input from the host device and the carrier frequency,
Provided on the transmission side a timing control unit for changing the delay time of the calibration signal for measuring the delay time of the antenna peripheral circuit in the no-signal section of the time division switching part of the transmission time and the reception time,
Means for folding the calibration signal from the antenna peripheral circuit to the receiving side;
Means for calculating a correlation between the transmission calibration signal and the folded calibration signal;
A TDD wireless communication apparatus comprising means for performing delay adjustment of the digital signal at the intermediate frequency based on the correlation result. A code generator holding a calibration signal of the frequency of the main signal input from the host device and a calibration signal of an intermediate frequency between the frequency of the main signal and the carrier frequency;
A DUC that converts the frequency of the main signal to the intermediate frequency;
A timing control unit that inserts a calibration signal of the frequency of the main signal into the main signal from the DUC in a no-signal section of a time-division switching part between the transmission time and the reception time, and changes the delay time;
An antenna peripheral circuit that passes the main signal to and from the antenna and folds back the calibration signal whose delay time is changed in the no-signal section to the receiving side,
A DDC that converts the frequency of the received main signal and the folded calibration signal from the intermediate frequency to the frequency of the main signal;
A correlator for performing a correlation calculation between the calibration signal held by the code generator and the calibration signal output from the DDC;
A TDD wireless communication apparatus, comprising: a delay adjustment unit configured to adjust a delay of a transmission main signal and a reception main signal at the intermediate frequency by a control signal from the host apparatus based on a result of the correlation calculation. A plurality of X sets of the DUC, the timing control unit, the code generation unit, and the delay adjustment unit on the transmission side are connected in parallel, and a processing unit is provided so that the carrier frequencies of transmission signals are bundled so as not to overlap on the frequency axis ,
3. The multi-path according to claim 2, further comprising: a delay-side adjustment unit on the reception side, a plurality of X sets of the DDC and the correlator connected in parallel, and a processing unit for separating the multiplexed reception signals. A TDD wireless communication apparatus having a carrier configuration.   4. The TDD wireless communication apparatus according to claim 2, wherein a plurality of the antennas and the antenna sharing control unit are provided to have a multi-channel configuration. 5.

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