JP3099722B2 - Diversity wireless communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity radio communication apparatus that performs maximum ratio combining with a desired signal even when an interference signal level is higher than a desired signal.

[0002]

2. Description of the Related Art Conventionally, regarding this kind of diversity radio communication apparatus, a paper "CW interference wave rejection characteristics by decision feedback equalization in multipath propagation path" published in IEICE Spring Conference 2-418 in 1992 has been proposed. "It has been known.

FIG. 6 is a block diagram showing a configuration of a diversity receiving apparatus to which such a conventional maximum ratio combining method is applied. In FIG. 6, a transmission wave from a transmission device is transmitted through a radio wave propagation path to a plurality of diversity antennas Ant1.
... received by AntN. This received signal is represented by the following equation (1). Diversity routes 1 and 2 are given by the following equation (2)
This is indicated by (3).

[0004]

(Equation 1)

(Equation 2)

(Equation 3)

[0005] In Equations (2) and (3), "hi
^“1 , hi ² ” is an impulse response at time i, and “a
“ _ni ” is transmission data at time ( _ni ). The numbers on the right shoulder indicate the diversity route.

[0006] Diversity antennas Ant1 ... Ant
The received signal from N is subjected to processing such as frequency conversion in receivers (RX) 60a... 60n, and the diversity route signals are weighted in complex multipliers 61a. Thereafter, the image is synthesized by the synthesizer 503. The weighting process of the complex multipliers 61a.
3 and automatic gain control amplifier (AGC: Automatic
Gain Control Amplifier) A correlation value between the signal whose amplitude level is normalized by 65 and the received signal is used.

The correlation value is input from the correlators 62a and 62b to the complex multipliers 61a... 61n, and is multiplied by the received signal to control the amplitude and phase of the signal in each diversity route. Here, the diversity route is 2, and the weight values in the complex multipliers 61a.
Assuming that 2, the combined signal can be expressed by the following equation (4) using (Equation 1) and (Equation 2).

[0008]

(Equation 4)

In this case, “w1 · hi ¹ + w2 · hi ²
= 1 ” . This corresponds to the complex multiplier 6 described above.
Automatic gain control amplifier 65 for weight processing of 1a ... 61n
This is because the correlation value between the signal whose amplitude has been normalized by the above and the received signal is used. From the above, (Equation 4) is simplified as in the following Equation (5).

[0010]

(Equation 5)

The weight value w1 in the diversity route 1 is calculated by the following equation (6) using (Equation 2) and (Equation 5).
Can be expressed as

[0012]

(Equation 6)

Therefore, the following equation (7) is obtained from the equations (4) and (6).
Can be represented by

[0014]

(Equation 7)

The parentheses in the expression (7) are complex conjugate multiplications, and the expression (7) indicates square combination. That is,
This is the maximum ratio combination. The specific gravity of the weight is increased for a signal having a high level and equivalent to a large h1, and the specific gravity is reduced for a signal having a low level. Therefore, maximum ratio combining is performed for the highest signal level. This is the maximum ratio combiner (MRC)
ineer), but also the problem of maximum ratio combiners, as will be described later.

The combined signal is input to a decision feedback equalizer (DFE) 64. The decision feedback equalizer 64 sends out an output signal from which a fast wave and a slow wave have been removed due to the occurrence of multipath fading in the radio wave propagation path.

[0017]

However, in the above-described conventional diversity receiving apparatus, when the signal level of the interference wave becomes equal to or higher than the desired wave, the signal pair for the interference wave having a relatively high level is reduced. Noise ratio (S /
N: Signal to Noise ratio) is controlled to the maximum, and the desired wave is not combined at the maximum ratio, and the diversity order is degenerated. That is, the maximum ratio combiner performs the maximum ratio combining on the signal level of the highest interference wave without considering the desired wave and the interference wave, and there is a disadvantage that the transmission efficiency and the transmission reliability are deteriorated.

The present invention solves such a problem in the prior art, and can perform maximum ratio combining on a desired wave without being affected by a relative level difference between a desired wave and an interference wave. It is an object of the present invention to provide a diversity wireless communication device whose transmission efficiency and transmission reliability are improved.

[0019]

To achieve the above object, a diversity radio communication apparatus according to the first aspect of the present invention comprises a modulated transmission signal and a level higher than the modulated transmission signal.
A transmitting device for multiplexing and transmitting the carrier signal of the
Diversity reception of the transmission wave transmitted by the transmitting device
Means for splitting the received signal and whether
The carrier signal extracted by the band-pass filter from
Combining means for performing maximum ratio combining by using
Combined signal of the other received signal that is branched using
Signal to maximize the signal-to-noise ratio.
And a carrier multiplexed by the transmitting device.
Decision feedback that removes the signal from the received signal after maximum ratio combining
A diversity receiving apparatus having means for performing Equalization
It is provided as a configuration.

According to a second aspect of the present invention, there is provided a diversity radio communication apparatus as the transmitting apparatus according to the first aspect, wherein the transmitting section transmits the transmitting signal to the modulating section, a local oscillation section transmitting a carrier signal to the modulating section, It is configured to include an adder for adding the modulated transmission signal and the carrier signal from the local oscillator, and a transmitter for wirelessly transmitting the signal from the adder.

According to a third aspect of the present invention, there is provided the diversity wireless communication apparatus as the diversity receiving apparatus according to the first aspect, wherein a plurality of receiving means for diversity receiving the transmission wave from the transmitting apparatus, and a diversity route for each diversity route output from the receiving means. A plurality of first multiplying / correlating means for controlling the phase and amplitude of the received signal; a first maximum ratio combining means for performing a maximum ratio combining of output signals of the plurality of first multiplying / correlating means;
Decision feedback equalization means for performing decision feedback equalization for removing the carrier signal multiplexed by the transmission device from the output signal of the maximum ratio combining means, and multiplexing by the transmission device from the reception signal output by the reception means. Band-pass filter to extract the
A filter, a plurality of second multiplying / correlation means for controlling the phase and amplitude of the output signal of the band-pass filter, and multiplexed by the transmission apparatus performs maximum ratio combining of the output signals of the plurality of second multiplication / correlation means Second maximum ratio combining means for extracting a carrier signal, and automatic gain control amplifying means for normalizing the amplitude level of the output signal of the second maximum ratio combining means and outputting as a reference signal in a plurality of first multiplying / correlating means This is a configuration including:

According to a fourth aspect of the present invention, there is provided the diversity wireless communication apparatus as the diversity receiving apparatus according to the first aspect, wherein a plurality of receiving means for diversity receiving the transmission wave from the transmitting apparatus and a diversity output from the plurality of receiving means. A plurality of first multiplication / correlation means for controlling a phase and an amplitude of a reception signal for each route;
First maximum ratio combining means for performing maximum ratio combining of output signals of the correlation means, and decision feedback equalizing means for removing a carrier signal multiplexed by the transmitting device from an output signal of the first maximum ratio combining means A band-pass filter that extracts a carrier signal multiplexed by a transmitting device from a received signal of one of a plurality of diversity routes output by the plurality of receiving means, and an output signal of the band-pass filter. Are normalized, and the plurality of first multiplications /
Automatic gain control amplification means for outputting as a reference signal in the correlation means.

According to a fifth aspect of the present invention, there is provided a diversity wireless communication apparatus configured to perform phase modulation as modulation of a transmission signal in the transmission apparatus according to the first aspect.

In the diversity wireless communication apparatus according to the present invention, the transmitting apparatus multiplexes and transmits the carrier wave, and the diversity receiving apparatus multiplexes the carrier for each diversity route. The extracted carrier signal is extracted and its amplitude and phase are controlled. Further, a carrier signal multiplexed by the transmitting device, which becomes unnecessary after the maximum ratio combining by the decision feedback type equalizing means of the center tap, is removed. Therefore, the maximum ratio combining is performed only on the desired wave without being affected by the relative level relationship between the interference wave and the desired wave.

Further, since the center tap decision feedback equalization is performed, the distortion generated in the desired wave is removed by removing the carrier signal multiplexed by the transmitting device. Also, it is difficult to increase the level of a desired signal in a wide band due to problems such as linearity and sight rope, but it is easy to increase the level of a carrier signal multiplexed by a narrow band transmitter, so that In addition, the circuit configuration is simplified, and transmission efficiency and transmission reliability are improved.

According to a fourth aspect of the present invention, a diversity wireless communication apparatus extracts a carrier signal multiplexed by a transmitting apparatus from a received signal of one diversity route by using a single band-pass filter, normalizes the amplitude of the output signal, and extracts Since it is used for signals, the circuit configuration is further simplified.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a diversity radio communication apparatus according to an embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of a diversity wireless communication apparatus according to an embodiment of the present invention. In FIG. 1, a transmitting device includes a modulator (MO) for modulating a transmission signal.
D) 100a and a local oscillator 100b for sending a carrier signal to the modulator 100a. Further, an adder 101 that adds the modulated transmission signal from the modulator 100a and the carrier signal from the local oscillator 100b, converts the signal from the adder 101 to a transmission frequency, and amplifies the power and wirelessly transmits the signal. Transmission frequency converter (TX) 102
And an antenna Ant11.

The diversity receiving apparatus includes diversity antennas Ant21 to Ant2N for diversity receiving the transmission wave Wa from the transmitting apparatus, and receivers (RX) 103a for performing processing such as frequency conversion on a received signal.
103n. Further, the receivers 103a ... 1
104n and correlators 105a... 105n for controlling the phase and amplitude of the received signal for each diversity route outputted by the receiver 03n, and the multipliers 104a.
And a combiner 106 for performing maximum ratio combining of the 4n output signals.

Also, a carrier wave multiplexed by the transmitting device (hereinafter referred to as a carrier wave signal on the transmission side; CW: Carrier Wave) signal is removed from the output signal of the combiner 106, that is, a center tap decision feedback for removing carrier wave interference. Shape equalizer 107
And a band-pass filter (BP) for extracting a transmission-side carrier signal from the reception signals output by the receivers 103a to 103n.
F) 108a... 108n and the bandpass filter 10
.. 108n and multipliers 109a... 109n and correlators 112a.
And

Further, a combiner 110 for extracting the carrier signal on the transmission side by performing maximum ratio combining of the output signals of the multipliers 109a... 109n, and a correlator 105a for normalizing the amplitude level of the output signal of the combiner 110. 105n and 112
a ... 112n and an automatic gain control (AGC) amplifier 111 for outputting as a reference signal.

Next, the operation of this embodiment will be described. In the transmission device, a transmission signal is input to the modulator 100a, and phase modulation (PSK: Phase Shift Keying) is performed.
This modulated transmission signal is input to adder 101. Here, it is multiplexed with the carrier wave output from the local oscillator 100b that is input simultaneously. Thereafter, the transmission frequency converter 10
The signal is converted into a transmission frequency at 2 and radiated as a transmission wave Wa from the antenna Ant11.

FIG. 2 is a frequency spectrum diagram of a carrier multiplexed transmission signal. In FIG. 2, a transmission wave Wa (transmission signal) includes a carrier (transmission-side carrier) 201 and a transmission signal 202 multiplexed by the transmission device. In the figure, the horizontal axis indicates the frequency, and the vertical axis indicates the level. Here, the carrier wave level multiplexed by the transmitting device is higher than the level of the transmission signal.
In this embodiment, the phase and amplitude are controlled by using a carrier (transmitting side carrier) signal multiplexed by the transmitting device.
If the transmission side carrier signal level is lower than the transmission signal, the maximum ratio combining is not performed on the transmission side carrier signal, so that the transmission side carrier signal level must always be set high.

When viewed on the frequency axis, the transmitting carrier signal is located at the center of the transmitting signal. This is the modulator 10
This is because the same carrier signal as the transmitting side is supplied to 0, but the number of circuits to be added is reduced, and it is not necessary to use another frequency band, and the signal processing is simplified. Will be. As described above, when transmission and reception are performed by multiplexing a carrier signal within the frequency of a transmission signal by a transmission device, a center tap decision feedback equalizer (center tap DFE) in a reception device, which will be described in detail later, is required. Becomes

In the receiving apparatus, the transmission wave Wa in which multipath fading has occurred in the radio wave propagation path is received by the diversity antennas Ant21 to Ant2N. The reception signals of the diversity route output from the diversity antennas Ant21 to Ant2N are received by the receiver (RX) 10
After processing such as frequency conversion is performed in 3a, the band-pass filter 108a, the multiplier 104a, and the correlator 105a
Is input to Similarly, after processing such as frequency conversion is performed in the receiver 103n, the signal is input to the band-pass filter 108n, the multiplier 104n, and the correlator 105n. The band-pass filters 108a to 108n have the same center frequency as the transmission-side carrier signal, and extract the transmission-side carrier signal.

FIG. 3 shows band-pass filters 108a.
FIG. 3A is a diagram showing the state of extraction of the transmission-side carrier signal at n. FIG. 3A shows a state before passing through the band-pass filters 108a to 108n, and FIG. The transmission-side carrier signals extracted by the band-pass filters 108a to 108n are input to multipliers 109a to 109n and correlators 112a to 112n. Multiplier 109a ...
The transmission-side carrier signal weighted at 109n is input to the combiner 110 and combined.

The transmission-side carrier signal level synthesized by the synthesizer 110 is normalized by the automatic gain control amplifier 111, and the transmission-side carrier signal is fed back to the correlators 112a to 112n. 112n correlate the transmission-side carrier signal output from the band-pass filters 108a to 108n with the transmission-side carrier signal normalized by the automatic gain control amplifier 111. This correlation value is input to multipliers 109a ... 109n, respectively. The multipliers 109a to 109n control the amplitude and phase of the carrier signal on the transmission side extracted by the band-pass filters 108a to 108n based on the correlation values. That is, in these diversity routes, the maximum ratio combining of the carrier signals on the transmission side is performed.

On the other hand, the signals are output by the receivers 103a to 103n.
Received signal for each diversity route split
, The multipliers 104a... 104n and the correlators 105a.
05n. The multipliers 104a.
The received signal subjected to the write processing is input to the synthesizer 106 and synthesized.
I do. Correlator 105a at the time of the wait process ... 105 n
Is normalized by the automatic gain control amplifier 111.
This is the transmission-side carrier signal after the maximum ratio combining.

After the weight processing, the received signal subjected to the maximum ratio combining in the combiner 106 is output to the center tap decision feedback equalizer 10.
7 is input. This center tap decision feedback equalizer 10
At 7, the transmission-side carrier signal is removed. Here, the difference from the conventional decision feedback equalizer (DFE) is that the reference tap of the forward equalizer of the decision feedback equalizer is not located at the final tap but at the center tap.

As a result, the forward equalizer located on the time axis advanced from the reference operates, and as a result of the linear combination, a deep notch filtering characteristic of a narrow band is exhibited. This filtering characteristic is frequency-selective, and it is possible to remove a carrier wave signal on the transmitting side that is discrete in frequency. The filtering causes waveform distortion of the desired wave, which is equalized by the rear equalizer in the DEF.

FIG. 4 shows a center tap decision feedback equalizer 107.
FIG. 4A shows a reception signal including a transmission-side carrier signal after maximum ratio combining (before passing through the center tap decision feedback equalizer 107), and FIG. Shows the state after the carrier signal on the transmission side has been removed by the forward equalizer of the decision feedback equalizer. FIG. 4C shows the state after the equalization by the backward equalizer.

As described above, the center tap decision feedback equalizer 107 removes the transmission-side carrier signal multiplexed at the time of transmission, and makes it possible to reproduce a received signal without distortion generated by the notch filter.

Next, another embodiment will be described. FIG. 5 is a block diagram showing a configuration of another embodiment. FIG.
In the embodiment of the present invention, as compared with the configuration shown in FIG. 1, a transmission-side carrier signal in which the level after the maximum ratio combining is normalized is not used for the correlation value for controlling the amplitude and the phase. That is, the receiver (RX) 103 which is one diversity route
The transmission-side carrier signal is extracted by the band-pass filter (BPF 508) only from the reception signal output by the signal a.

The amplitude level of the carrier signal on the transmitting side extracted by the band-pass filter 508 is controlled by automatic gain control (AGC).
The result is normalized by the amplifier 509 and input to the correlators 105a to 105n. Other operations are the same as those of the configuration shown in FIG. In this configuration, the bandpass filter 108a shown in FIG.
.. 108n, multipliers 109a ... 109n, correlator 112
a ... 112n and the combiner 110 are not required, and there is an advantage that the circuit scale is reduced.

[0044]

As is apparent from the above description, according to the diversity radio communication apparatus of the present invention, the carrier signal on the transmitting side is extracted for each diversity route, and its amplitude and phase are extracted. , And the carrier signal on the transmitting side is removed by the decision feedback equalization means of the center tap, so that the maximum ratio combining for the desired wave is not affected by the relative level relationship between the interference wave and the desired wave. Done.

Furthermore, since the center tap decision feedback equalization is performed, the distortion generated for the desired wave is removed by removing the carrier signal on the transmitting side, and the circuit configuration is simplified. As a result, transmission efficiency and transmission reliability are improved.

According to the diversity radio communication apparatus of the present invention, the carrier signal on the transmitting side is extracted from the received signal of one diversity route by one band-pass filter, and the amplitude of the output signal is normalized to become the reference signal. Since it is used, the circuit configuration can be further simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of a diversity wireless communication apparatus according to the present invention.

FIG. 2 is a spectrum diagram of a carrier-multiplexed transmission signal in the embodiment.

FIG. 3 is a diagram illustrating a transmitting-side carrier signal extraction state in a BPF according to the embodiment.

FIG. 4 is a diagram illustrating a processing state in a center tap DFE according to the embodiment.

FIG. 5 is a block diagram showing a configuration of another embodiment.

FIG. 6 is a block diagram showing a configuration of a diversity receiving apparatus to which a conventional maximum ratio combining method is applied.

[Explanation of symbols]

 100a modulator 100b local oscillator 101 adder 102 transmission frequency converter 103a ... 103n receiver 104a ... 104n, 109a ... 109n multiplier 105a ... 105n, 112a ... 112n correlator 106, 110 combiner 107 center tap decision feedback equalization 108a ... 108n Band-pass filter 111 Automatic gain control amplifier Ant11 Antenna Ant21 ... Ant2N Diversity antenna

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 1/76-3/44 H04B 3/50-3/60 H04B 7/00-7/12 H04L 1 / 02-1/06

Claims (5)

(57) [Claims] 1. A modulated transmission signal, and the modulated transmission signal
Transmitter that multiplexes and transmits a high-level carrier signal.
And diversity receiving the transmission wave transmitted by the transmitting device.
Means for splitting the received signal and extracting the signal from one of the split received signals with a band-pass filter
Combining means for performing maximum ratio combining on the carrier signal
And the other which is branched using the synthesized signal as a correlation signal.
To maximize the signal-to-noise ratio after combining the received signals
Means for combining each diversity received signal,
The carrier signal multiplexed by the device is
Means for performing decision feedback equalization for removing from the signal
And a diversity receiving apparatus.
Place. 2. The transmitting apparatus according to claim 1, wherein: a modulating means for modulating a transmission signal; a local oscillating means for transmitting a carrier signal to the modulating means; a modulated transmitting signal from the modulating means; A diversity wireless communication apparatus comprising: an adding unit that adds a carrier signal from the unit; and a transmitting unit that wirelessly transmits the signal from the adding unit. 3. A diversity receiving apparatus according to claim 1, wherein: a plurality of receiving means for diversity receiving a transmission wave from a transmitting apparatus; and a phase and amplitude of a received signal for each diversity route output by said receiving means. A plurality of first multiplying / correlating means, a first maximum ratio combining means for performing maximum ratio combining of output signals of the plurality of first multiplying / correlating means, and an output signal of the first maximum ratio combining means. A decision feedback equalizer for performing decision feedback equalization for removing a carrier signal multiplexed by the transmission device, and a band for extracting a carrier signal multiplexed by the transmission device from a reception signal output by the reception device. and pass filters, and a plurality of second multiplying / correlation means for controlling the phase and amplitude of the output signal of the band-pass filter, the maximum ratio of the output signal of said plurality of second multiplier / correlator means A second maximum ratio synthesizing unit for extracting a carrier signal multiplexed by the transmitting apparatus, and normalizing an amplitude level of an output signal of the second maximum ratio synthesizing unit to generate the plurality of first multiplication / correlation. And an automatic gain control amplification means for outputting as a reference signal in the means. 4. A diversity receiving apparatus according to claim 1, wherein: a plurality of receiving means for diversity receiving a transmission wave from a transmitting apparatus; and a phase and an amplitude of a received signal for each diversity route output by said plurality of receiving means. A plurality of first multiplying / correlating means, a first maximum ratio combining means for performing maximum ratio combining of output signals of the plurality of first multiplying / correlating means, and an output of the first maximum ratio combining means. A decision feedback equalizer for removing a carrier signal multiplexed by the transmitting device from a signal; and a multiplexing process performed by the transmitting device from a received signal of one of a plurality of diversity routes output by the plurality of receiving devices. one <br/> a band-pass filter, a first multiplier / phase the amplitude of the output signal by normalizing the plurality of the band-pass filter for extracting the carrier signal Diversity wireless communication apparatus characterized by comprising an automatic gain control amplifying means for outputting a reference signal at means. 5. A diversity radio communication apparatus, wherein phase modulation is performed as modulation of a transmission signal in the transmission apparatus according to claim 1.