JP2008016989A - Diversity radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diversity radio communication apparatus capable of selecting the optimum reception antenna system without limiting the length of a TDMA channel. <P>SOLUTION: The apparatus includes: a gain control unit 22 for a reception analog signal; a logarithm detector 23; an A/D 24; an integrator 27 for integration over a fixed period; a peak hold circuit 28 for detecting a peak level from an integration signal as an AGC voltage and holding it; and a D/A 25 for performing conversion into an analog signal to control the gain control unit 22, as a high-speed response AGC loop by each one of the reception antenna systems. The apparatus also includes: a rate converter 29 for digitizing the reception analog signal from the gain control unit 22 and, then, converting it into base band data; and a reception antenna changeover 30 for inputting the base band data from each reception antenna system, selecting the base band data of one reception antenna system based on the AGC voltage corresponding to the respective reception antenna systems, and outputting the data to a demodulating circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diversity wireless communication apparatus, and more particularly to a diversity wireless communication apparatus that effectively selects a receiving antenna system that receives a TDMA signal.

In the conventional diversity wireless communication apparatus, for example, as described in Japanese Patent Application Laid-Open No. 2001-34579 “OFDM receiving apparatus using selection diversity”, it is set by signal control information and correlation detection information. The integrated power of the received signal is measured while switching the integration period and timing according to the measured power measurement control information, the antenna that obtains the largest integrated power result is selected, and the received signal is demodulated. .
JP 2001-345779 A (page 6-7).

  However, in the conventional system in which the TDMA signal is diversity-received and switched to the optimum receiving antenna, the received antenna strength to be switched after the received electric field strength is accumulated and averaged for a sufficient time by the analog circuit It was the composition of selecting. As a result, it is difficult to select the receiving antenna by properly determining the reception field strength of each TDMA channel of the TDMA signal, which affects the TDMA channel frame length of TDMA and limits the number of TDMA channels. There was a problem.

  The present invention has been made in view of such a problem, and diversity under which conditions for using selective diversity with respect to a TDMA signal can be selected without limiting the TDMA channel length. The object is to provide a wireless communication device.

  In order to solve the above-described problem, the diversity wireless communication apparatus according to the present invention employs the following characteristic configuration.

(1) In a diversity wireless communication apparatus that receives TDMA signals composed of a plurality of channel frames by a plurality of receiving antenna systems and selects a receiving antenna system based on the received electric field strength, a predetermined timing in each channel frame A diversity wireless communication apparatus in which an AGC loop capable of high-speed response within a range is provided for each reception antenna system, and a reception antenna system that is effective for each channel frame is determined based on AGC control information for controlling each AGC loop.
(2) The diversity wireless communication apparatus according to (1), wherein the AGC control information of each AGC loop is an AGC voltage corresponding to a reception electric field strength of each reception antenna system.
(3) The diversity wireless communication apparatus according to (2), wherein an integrated value during an integration time having a predetermined length is used as the AGC voltage.
(4) Any of the above (1) to (3), wherein the AGC control information of each AGC loop is determined based only on the received electric field strength of a received signal in a predetermined period within each channel frame. Diversity wireless communication device.
(5) The diversity wireless communication apparatus according to (4), wherein the partial period in each channel frame is a predetermined period from the beginning immediately after the guard time of each channel frame.
(6) The AGC loop installed corresponding to the receiving antenna system controls the gain of the analog signal received by the antenna, the detector for detecting the output of the AGC, and the output of the detector for converting it into a digital signal A / D converter, an integrator that integrates a digital signal from the A / D converter every integration time of a predetermined length, a peak from one or more integration values output from the integrator A peak hold circuit that detects and holds a level as an AGC voltage, and a D / A converter that converts the AGC voltage held by the peak hold circuit into an analog signal for controlling the AGC. The diversity wireless communication device according to any one of (1) to (5).
(7) A rate conversion unit that converts a reception analog signal output from the AGC into a digital signal and converts it into baseband data in an intermediate frequency band is provided for each reception antenna system, and for each reception antenna system Based on the AGC voltage held in each peak hold circuit corresponding to each receiving antenna system by inputting baseband data from each rate converting section, the rate conversion section corresponding to any receiving antenna system The diversity wireless communication apparatus according to (6), further including a reception antenna switching unit that selects baseband data from the receiver and outputs the baseband data to the demodulation circuit unit.
(8) From the rate conversion unit corresponding to the reception antenna system corresponding to the highest AGC voltage among the AGC voltages held by the peak hold circuits corresponding to the reception antenna systems, The diversity wireless communication apparatus according to (7), which selects baseband data.
(9) When the receiving antenna switching unit compares the AGC voltage held by each of the peak hold circuits corresponding to each receiving antenna system, the receiving antenna switching unit has a hysteresis characteristic indicating a switching history of the receiving antenna system so far. The diversity wireless communication apparatus according to (7), wherein comparison is performed using a threshold value.
(10) When the peak hold circuit holds the AGC voltage as the AGC voltage, a period during which the peak level is detected from one or more integral values of the integrator is a predetermined constant from the beginning immediately after the guard time of each channel frame. The diversity wireless communication apparatus according to any one of (7) to (9), wherein the period is a period.

  According to the diversity wireless communication apparatus of the present invention, the following effects can be obtained.

  By using an AGC (Auto Gain Control) loop that has high-speed response performance within a predetermined timing range within a TDMA channel frame, the fading problem required for diversity control is reduced. Can be selected flexibly. Therefore, the number of TDMA channels that can be used by the user can be increased. In addition, since diversity control following a high-speed AGC loop can be performed, it can be effectively used for OFDM (Orthogonal Frequency Division Multiplexing), multicarrier modulation, and the like, which are wideband modulation.

  In addition, by detecting the peak value of the received signal only in a predetermined fixed interval, it is possible to avoid discontinuity of demodulated data due to switching of the receiving antenna system, and appropriate selection within each TDMA channel frame Diversity control is possible.

  Further, by using an A / D converter and a D / A converter with high resolution, a threshold value for selecting a receiving antenna system can be stably operated even in the case of a slight reception sensitivity. By giving hysteresis characteristics to the antenna, it is possible to easily prevent repeated switching of the receiving antenna system.

  Hereinafter, preferred embodiments of a diversity wireless communication apparatus according to the present invention will be described with reference to the accompanying drawings.

(Configuration of Example)
The diversity wireless communication apparatus according to the present invention realizes a selective diversity control system that follows high-speed AGC (Auto Gain Control) control, and is characterized by a high-speed AGC loop composed of analog AGC and digital AGC. Diversity control is performed by properly determining the received electric field strength of each receiving antenna by comparing the AGC control information of the AGC loop with the electric field strength of each channel of the TDMA signal received from each receiving antenna. It is.

  FIG. 1 is an overall system diagram for explaining an example of an entire system of a diversity wireless communication apparatus according to the present invention. In the overall system diagram of FIG. 1, a time-received power graph indicated by reference numeral 20 indicates that the diversity wireless communication device 10 receives the TDMA signal transmitted from the transmission device 18 indicated by the devices 1 to N. ing. Here, the diversity wireless communication apparatus 10 in this embodiment includes an antenna 1 11a, an analog AGC unit 12a, a digital AGC unit 13a, and an antenna 2 11b, an analog AGC unit 12b, and a digital AGC unit 13b. And the analog AGC unit 12a, the digital AGC unit 13a, the analog AGC unit 12b, and the digital AGC unit 13b form an AGC loop having high-speed response performance.

  Furthermore, the diversity wireless communication apparatus 10 includes a rate conversion unit 14 that converts output signals from the analog AGC unit 12a and the analog AGC unit 12b into baseband data in an intermediate frequency band, and an antenna 1 that is output from the rate conversion unit 14. Diversity selection circuit unit 15 that selects which of the two output signals of the system and the two antenna systems is used, demodulation circuit unit 16 that demodulates the output signal from the selected rate conversion unit 14, and demodulation circuit unit 16 A sample hold circuit 17 for holding a predetermined timing based on a synchronization signal extracted by a synchronization circuit (not shown).

  The timing signal from the sample hold circuit 17 is supplied to the digital AGC units 13a and 13b as, for example, a TDMA channel timing signal indicating the head of the TDMA channel frame, and the output voltage from the digital AGCs 13a and 13b at the time of the TDMA channel timing of each received signal. By extracting the data, that is, the AGC voltage and supplying it to the diversity selection circuit unit 15, the diversity selection circuit unit 15 outputs two outputs of the antenna 1 system and the antenna 2 system based on the AGC voltage at the TDMA channel timing. Select which signal to use.

  The example shown in the time-received power graph 20 shows an example in which the time slots of the TDMA channel are assigned in the order of the device 1, the device 4, the device N,... Until the TDMA signals from the devices 1 and 4, the reception level (reception field strength) of the receiving antenna 2 is higher than that of the receiving antenna 1, and when the TDMA signals from the devices N,. The case where the reception level (reception electric field strength) of the receiving antenna 1 is higher than that of the receiving antenna 2 is shown.

That is, the diversity wireless communication apparatus according to the present invention uses a plurality of receiving antenna systems (two receiving antenna systems in the case of FIG. 1) and uses OFDM (Orthogonal) which is a wideband modulation.
Frequency Division Multiplexing) and multicarrier modulation TDMA signals are received, each TDMA signal received by each receiving antenna is digitally processed, demodulated, and a predetermined predetermined channel frame of the TDMA signal received from each receiving antenna. AGC control information (that is, an AGC voltage corresponding to the reception level (reception field strength) of each reception antenna) of the AGC loop capable of high-speed response within the timing range is monitored to determine a reception antenna system that enables reception. It is configured to switch.

  FIG. 2 is a block diagram showing an example of a specific circuit configuration of the diversity wireless communication apparatus according to the present invention. The details of the TDMA signal receiving operation in the diversity wireless communication apparatus 10 of FIG. However, the circuit blocks of the other antenna systems have the same configuration. As shown in FIG. 2, the diversity wireless communication apparatus 10 includes an analog unit 10A and a digital unit 10B for each antenna system (the antenna system 1 is shown in FIG. 2). Are an LNA (Low Noise Amplifier) 21, a gain controller (AGC) 22, a logarithmic detector 23, an A / D (A / D converter) 24, and a D / A (D / A converter). 25, an A / D (A / D converter) 26, and the digital unit 10B includes at least an integrator 27, a peak hold circuit unit 28, a reception 1 rate conversion unit 29, a reception antenna switching unit 30, and a synchronization circuit 31. It consists of

(Description of operation of the embodiment)
Next, an example of the operation will be described in detail using the diversity wireless communication device 10 of FIG. Here, in the following description, a case where wideband multicarrier modulation is used as a received signal waveform will be described as an example. Received radio wave 1 received by antennas 1 and 11 a is amplified by LNA 21, converted to a digital signal by A / D 26 via gain control unit 22, and output to reception 1 rate conversion unit 29. Is done. The reception 1 rate conversion unit 29 converts the digital signal input from the A / D 26 into reception 1 rate conversion data (baseband data) in the intermediate frequency band, and outputs it to the reception antenna switching unit 30.

  In the reception antenna switching unit 30, reception 1 peak data output from the peak hold circuit unit 28 of one antenna system and reception 2 peak data output from a peak hold circuit unit (not shown) of two antenna systems. As a result of the comparison, the antenna system showing a higher peak value is selected. For example, when the reception 1 peak data is at a higher level, the reception 1 rate from the reception 1 rate conversion unit 29 of the antenna 1 system is Of the conversion data and the reception 2 rate conversion data from the reception 2 rate conversion unit (not shown) of the two antenna systems, the reception 1 rate conversion data is selected and output to the demodulation circuit unit 16.

  Also, the received signal that has been subjected to analog AGC control by the gain control unit 22 generates a signal for performing diversity switching determination, that is, AGC loop AGC control information (an AGC voltage corresponding to the reception level of each receiving antenna) at high speed. For this purpose, the signal is detected by the logarithmic detector 23 and then converted into a digital signal by the A / D 24. The digital signal converted by the A / D 24 is integrated over a predetermined integration time by the integrator 27, and an average reception level (reception electric field strength) in the integration time is calculated. Here, FIG. 3 is an explanatory diagram for explaining an example of the integration operation of the input signal in the integrator 27 of the diversity wireless communication apparatus 10 which is an example of the present invention.

  As shown in FIG. 3, the input digital signal is integrated for a predetermined integration time so that an input digital signal (AGC voltage) corresponding to the reception level of the reception signal can be obtained more accurately. As voltage data output at sampling times t0, t1, t2, and t3, Data (t0), Data (t1), Data (t2), and Data (t3) from each sampling time to a period that is backed by the period of integration time T, respectively. ) Is output. One or more voltage data (integrated values) output from the integrator 27 are supplied to the peak hold circuit unit 28, and the peak hold circuit unit 28 uses the highest integrated value (in the example shown in FIG. (Integral value of Data (t2)) is held as a peak level in the channel frame corresponding to the period, that is, AGC control information (an AGC voltage corresponding to the reception level of the reception antennas 1 and 11a). Thereafter, the signal is converted into an analog control signal by the D / A 25 and fed back to the gain control unit 22 to control the gain of the gain control unit 22.

  As described above, the reception signal output from the LNA 21 can operate at a high response speed including the gain control unit 22, the logarithmic detector 23, the A / D 24, the integrator 27, the peak hold circuit unit 28, and the D / A 25. The gain is controlled by being applied to the AGC loop, and the main waveform is converted into a digital signal by the A / D 26 and supplied to the reception 1 rate conversion unit 29. The response performance of the AGC loop is a response performance capable of operating at an extremely high speed within a predetermined timing range that is determined in advance as the integration time T and the operation period of the peak hold circuit section 28. The details of the AGC loop are well known to those skilled in the art, and further detailed description thereof is omitted here.

  Here, during the operation period in which the AGC voltage, that is, the peak hold circuit unit 28 that detects the peak value of the received signal is operated, the discontinuity of the demodulated data due to the switching of the receiving antenna system is avoided, and the proper within each TDMA channel frame. In order to enable selective diversity control, it is set to be limited to only a part of the period in the TDMA channel frame. FIG. 4 is an explanatory diagram for explaining an example of an operation period of the peak hold circuit unit 28 of the diversity wireless communication apparatus 10 as an example of the present invention. After the synchronization of the received TDMA signal is established, FIG. As an example of the operation period (peak detection time) for detecting the peak level of the signal, each TDMA channel frame (TDMA channel 1, TDMA channel 2, TDMA channel 3, TDMA channel 4,...) Of the received TDMA signal. An example in which only the head part operates is shown.

  Further, as described above, the peak value (AGC voltage) of the reception signal held in the peak hold circuit unit 28 is fed back to the gain control unit 22 via the D / A 25 and received as reception one peak data. Also supplied to the antenna switching unit 30. The reception antenna switching unit 30 compares and determines the reception 1 peak data from the peak hold circuit unit 28 of one antenna system and the reception 2 peak data from the peak hold circuit unit (not shown) of two antenna systems. For example, when the reception 1 peak data of one antenna system is at a higher reception level, the reception 1 rate conversion data from the reception 1 rate conversion unit 29 is shown in FIG. Is supplied to the demodulating circuit 16 and also supplied to the synchronizing circuit 31 in order to detect a synchronizing signal from the received 1-rate conversion data.

  The synchronization circuit 31 detects a synchronization signal included in the received 1-rate conversion data immediately after the guard time, establishes synchronization, and designates an operation period for holding the reception peak level in the peak hold circuit unit 28. The TDMA channel timing signal is generated and output to the peak hold circuit unit 28. As a result, as shown in FIG. 4, in a part of the TDMA channel frame, for example, a part of the beginning of the TDMA channel frame, the peak level in the channel frame corresponding to the period, ie, diversity control is required. It is possible to output as AGC control information (AGC voltage corresponding to the reception level of the receiving antenna) within the requested section, thereby avoiding discontinuity of demodulated data due to switching of the receiving antenna system, and within each TDMA channel frame Therefore, it is possible to perform appropriate selectivity diversity control.

  When the synchronization is not established, the operation of automatically switching the antenna 1 system and the antenna 2 system sequentially and establishing synchronization in the synchronization circuit 31 based on any rate conversion data is performed. After the synchronization is established by repeating, the selection operation of the antenna system to be received is performed by performing the comparison / determination operation of the reception data of the reception signal, that is, the peak data regarding the AGC voltage as described above.

  Further, by increasing the resolution of the A / D 24 and D / A 25 forming the AGC loop, the AGC loop can be operated in a stable state even when the reception sensitivity is small, and the receiving antenna switching unit Since it is also possible to easily provide a hysteresis characteristic to the threshold value for selecting the antenna system in 30, it is possible to prevent the occurrence of an unstable hunting switching operation that repeatedly switches the receiving antenna system. it can.

  In the case of a TDMA signal, a guard time is prepared between the channel frames in order to prevent interference between the channel frames. Therefore, during this guard time period, the gain of the gain control unit 22 is a full gain. It has returned to the state. When an AGC loop having high-speed response performance is used, when the received signal waveform is input after the guard time period has elapsed, the gain of the gain control unit 22 decreases with time from the full gain state. , And by detecting the peak level in one or more voltage data integrated within the period of the peak detection time shown in FIG. 4, two received data of received 1 rate conversion data and received 2 rate conversion data are detected. Any of the antenna systems can be selected as an appropriate reception system for receiving the TDMA channel frame.

(Explanation of effect)
As described above, in the present invention, diversity control is required by using an AGC loop that includes analog AGC and digital AGC and has high-speed response performance within a predetermined timing range within a TDMA channel frame. Therefore, the TDMA channel length can be selected flexibly. Therefore, the number of TDMA channels that can be used by the user can be increased. In addition, since diversity control following a high-speed AGC loop can be performed, it can be effectively used for OFDM, multicarrier modulation, and the like, which are wideband modulations.

  In addition, by detecting the peak value of the received signal, that is, the peak value of the AGC voltage only in a predetermined interval within the TDMA channel frame, it is possible to avoid discontinuity of demodulated data due to switching of the receiving antenna system. Therefore, it is possible to perform appropriate selectivity diversity control within each TDMA channel frame.

  Further, by using an A / D converter and a D / A converter with a high resolution, the AGC loop can be stably operated even in the case of a slight reception sensitivity, and a threshold value for selecting a reception antenna system By providing hysteresis characteristics to the antenna, it is possible to easily prevent repeated switching of the receiving antenna system.

  The configuration of the preferred embodiment of the present invention has been described above. However, it should be noted that such examples are merely illustrative of the invention and do not limit the invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made according to a specific application without departing from the gist of the present invention.

It is a whole system diagram for demonstrating an example of the whole system of the diversity radio | wireless communication apparatus by this invention. It is a block block diagram which shows an example of the concrete circuit structure of the diversity radio | wireless communication apparatus by this invention. It is explanatory drawing for demonstrating an example of the integration operation | movement of the input signal in the integrator of the diversity radio | wireless communication apparatus which is an example of this invention. It is explanatory drawing for demonstrating an example of the operation period of the peak hold circuit part of the diversity radio | wireless communication apparatus which is an example of this invention.

Explanation of symbols

18 Transmitter 10 Diversity Radio Communication Device 10A Analog Unit 10B Digital Unit 11a Antenna 1
11b Antenna 2
12a, 12b Analog AGC unit 13a, 13b Digital AGC unit 14 Rate conversion unit 15 Diversity selection circuit unit 16 Demodulation circuit unit 17 Sample hold circuit unit 20 Time-received power graph 21 LNA
22 Gain Control Unit (AGC)
23 Logarithmic detector 24 A / D (A / D converter)
25 D / A (D / A converter)
26 A / D (A / D converter)
27 integrator 28 peak hold circuit unit 29 reception 1 rate conversion unit 30 reception antenna switching unit 31 synchronization circuit

Claims (10)

  In a diversity wireless communication apparatus that receives a TDMA signal composed of a plurality of channel frames by a plurality of receiving antenna systems and selects a receiving antenna system based on the received electric field strength, within a predetermined timing range in each channel frame A diversity wireless communication characterized in that an AGC loop capable of high-speed response is provided for each receiving antenna system, and an effective receiving antenna system is determined for each channel frame based on AGC control information for controlling each AGC loop. apparatus.   The diversity radio communication apparatus according to claim 1, wherein the AGC control information of each AGC loop is an AGC voltage corresponding to a reception electric field strength of each reception antenna system.   The diversity wireless communication apparatus according to claim 2, wherein an integrated value during an integration time having a predetermined length is used as the AGC voltage.   4. The AGC control information for each AGC loop is determined based only on the received electric field strength of a received signal for a predetermined period in each channel frame. Diversity wireless communication device.   5. The diversity wireless communication apparatus according to claim 4, wherein the partial period in each channel frame is a predetermined period from the beginning immediately after the guard time of each channel frame.   The AGC loop installed corresponding to the receiving antenna system controls the gain of the analog signal received by the antenna, the detector for detecting the output of the AGC, and the A / D conversion for converting the output of the detector into a digital signal An integrator that integrates the digital signal from the A / D converter every predetermined integration time of a predetermined length, and the peak level is selected from among one or more integration values output from the integrator. A peak hold circuit that detects and holds a voltage, and a D / A converter that converts the AGC voltage held by the peak hold circuit into an analog signal for controlling the AGC. A diversity wireless communication apparatus according to any one of claims 1 to 5.   A rate conversion unit that converts a received analog signal output from the AGC into a digital signal and converts it into baseband data in an intermediate frequency band, provided for each receiving antenna system, and the rate conversion corresponding to each receiving antenna system Baseband data from each rate conversion unit corresponding to any receiving antenna system based on the AGC voltage held by each peak hold circuit corresponding to each receiving antenna system. The diversity wireless communication apparatus according to claim 6, further comprising a reception antenna switching unit that selects band data and outputs the selected band data to the demodulation circuit unit.   Baseband data from the rate conversion unit corresponding to the reception antenna system corresponding to the highest AGC voltage among the AGC voltages held by the peak hold circuit corresponding to each reception antenna system by the reception antenna switching unit. The diversity wireless communication apparatus according to claim 7, wherein:   When the receiving antenna switching unit compares the AGC voltage held by each of the peak hold circuits corresponding to each receiving antenna system, a threshold having a hysteresis characteristic indicating a switching history of the receiving antenna system so far is used. The diversity wireless communication apparatus according to claim 7, wherein   When the peak hold circuit holds the AGC voltage as the AGC voltage, the period during which the peak level is detected from one or more integral values of the integrator is a predetermined period determined from the beginning immediately after the guard time of each channel frame. The diversity wireless communication device according to claim 7, wherein the diversity wireless communication device is a wireless communication device.

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