KR100800987B1 - Milliwave band radio communication method and system - Google Patents

Abstract

The receiver receives the RF band modulated signal received from the transmission and this and an unmodulated carrier having coherent phase noise characteristics, and restores the IF-to-source signal by generating a multiplicative component of both components. A small planar antenna having a light beam characteristic such as a one-element patch antenna, an amplifier generated on a microplanar circuit by the MMIC technology, and a mixer circuit are combined into one unit receiving circuit and compared with the wavelength of the IF band on the receiver. In short, a plurality of short circuits are arranged, and the power output of each unit receiving circuit is synthesized to function as a high gain antenna having a detection function, and to realize a light beam radiation characteristic similar to that of a single-element antenna. The synthesized IF versus composite output is demodulated in the IF versus demodulation circuit. The present invention not only enables the construction of a low cost wireless communication system, but also enables the transmission of a high quality signal, as well as the fabrication of an antenna of a high-gain and easy-to-use light beam.

Millimeter wave wireless communication system, RF band modulated signal, unmodulated carrier, flat printed small receiving antenna, micro flat receiving circuit

Description

Millimeter wave communication method and system

According to the present invention, an RF band modulated signal transmitted from a transmitter and a local oscillation signal having a coherent phase noise characteristic are also received at a receiver and generate a multiplier component of both components. The present invention relates to a millimeter wave wireless communication method and system for recovering a signal.

In a wireless device that transmits a high speed digital signal or a broadband analog signal, a function of generating and transmitting a radio modulation signal RF by uploading and converting the intermediate frequency band signal IF and the local oscillation signal L0. It is common to take a configuration comprising a transmitter having a receiver and a receiver having a function of receiving an RF, multiplying L0, and downconverting to generate an IF. In this case, in order to maintain the quality of the transmitted signal, it is required that the IF input to the transmitter and the IF generated by the receiver have a relationship between a predetermined frequency difference and a small time variation of the phase difference. For this reason, as a local oscillator which generates L0 in the transceiver, it is necessary to have excellent frequency stability and low phase noise. In particular, in the region of high frequency microwave milliwaves, the noise is stabilized and reduced by a dielectric resonator or a phase lock loop (PLL) circuit.

However, as the frequency of use increases (for example, a millimeter wave of 30 GHz or more), it becomes difficult to realize a low noise oscillator with high stability and at the same time, the manufacturing cost increases. For example, in a dielectric resonator, the Q value (Quality Factor) is lowered and performance cannot be exhibited. In the PLL circuit, there is a problem in that the configuration of the divider is particularly difficult. There is also a method of obtaining L0 by multiplying the signal from a low frequency oscillator, but in general, an amplifier is required to increase the signal strength, becomes expensive, becomes larger, and consumes more power. Problems such as things happen.

In order to solve these problems, a radio communication apparatus (magnetic heterodyne system) described in Japanese Patent Laid-Open No. 2001-53640 shown in Fig. 9 is proposed. According to this example, the IF modulated signal of the data input to the transmitter 81 is multiplied by the local oscillation signal LO of the local oscillator 85 in the mixer 83, and the unnecessary wave component is performed by the band filter 86. The radio modulated signal RF is generated by eliminating. This RF is added to the power synthesizer 87 as part of the LO. The added radio signal is transmitted from the antenna Tx after increasing the signal level in the amplifier 88. On the other hand, in the receiver 82, the radio signal received at the antenna Rx is enlarged at the signal level at the amplifier 91, filtered at the filter 92 in the receiver, and demodulated to the IF at the power supply 93. In this method, the same LO as that used for generating the RF signal is transmitted as a radio signal. Accordingly, there is an advantage that the influence of the phase noise of the local oscillator 85, which becomes the L0 source, is canceled during demodulation, and the demodulated IF is demodulated to the frequency of the original IF input to the transmitter.

Japanese Laid-Open Patent Publication No. 2002-246921 also mixes an unmodulated carrier in a position where the frequency is dropped to a transmission IF modulated signal at a frequency interval corresponding to an IF frequency that becomes appropriate when demodulating it on the receiving side, and sums them up. A transmission circuit for upconverting and transmitting a millimeter wave with a millimeter wave local oscillation signal is disclosed.

However, there are some problems when designing and building an actual wireless system. For example, since the signal propagation loss is high at high frequencies such as millimeters, the above-described magnetic heterodyne method causes more sensitivity deterioration than the conventional upconverter method, so that at least the reception antenna has a relatively high gain. You need to use one. For example, when a high gain antenna is realized at a high frequency such as a millimeter band, a plurality of antenna elements may be arranged in an array to realize in-phase synthesis of signals obtained from each antenna element (this is called an array antenna). In order to synthesize the signal from each antenna element in an antenna in phase, the wavelength is shorter in the millimeter wave, so processing precision shorter than millimeter is required, so that the antenna is expensive or high gain as expected. It is very difficult to get performance.

In addition, when high gain is realized by array antennaization, high gain is usually obtained in the maximum radiation direction, but the relative gain characteristic (directive characteristic) with respect to the radiation angle is very narrow, which has a high gain in only one direction. It becomes a pensil beam, which is an antenna characteristic with a sidelobe including a null point where no antenna gain occurs.

Therefore, the present invention solves this problem, and aims to build a low-cost wireless communication system, enable the transmission of high-quality signals, as well as to manufacture a high-gain and easy-to-use light beam antenna. Doing.

In the present invention, a receiver receives an RF band modulated signal transmitted from a transmitter and an unmodulated carrier having a coherent phase noise characteristic and restores an IF band source signal by generating a multiplier component of both components. And a small planar antenna having a light beam characteristic such as a one-element patch antenna, and an amplifier and a mixer circuit generated on a microplanar circuit by MMIC technology as a unit receiver circuit. After a plurality of arrangements are made short enough in comparison with each other, by combining the detection outputs of the respective receiving circuits, they can function as high-gain antennas having a detection function, and can realize the same light beam radiation characteristics as those of one-element antennas. It features.

In the millimeter wave wireless communication method and system of the present invention, a receiving circuit combining a small receiving antenna and a planar receiving circuit is used as one component, and a plurality of receiving circuits serving as the one component are arranged short enough to compare with the wavelength of the IF band, The detection output detected by the respective receiving circuits is synthesized to output an IF-to-synthesis output, and the IF-to-synthesis output is input to demodulate. Then, before combining to the IF-to-synthesized output, phase adjustment and amplitude weighting are performed on the detected output detected by the individual receiving circuits.

In addition, the present invention is provided with three or more individual receiving circuits, arranged at irregular intervals between them. Further, the individual receiving circuits are arranged in two-dimensional or three-dimensional images in the longitudinal and transverse directions. Moreover, the antenna used by a transmitter can be used for circular polarization, and about half of the antenna used by a receiver can be used for horizontal polarization and the remainder for vertical polarization.

1A and 1B are diagrams illustrating the basic configuration of a transmission / reception circuit of a wireless communication system embodying the present invention.

2 is a diagram illustrating a transmitter configuration.

3A and 3B are diagrams illustrating a receiver configuration in which a micro planar circuit is constructed by a planar printed antenna and MMIC technology.

FIG. 4 is a diagram showing a receiving circuit (Example 1) that embodies the basic configuration shown in FIG.

FIG. 5 is a diagram showing a receiving circuit (Example 2) embodying the basic configuration shown in FIG.

6A and 6B are diagrams showing a receiving circuit (Example 3) embodying the basic configuration shown in FIG.

FIG. 7 is a diagram for explaining the spacing adjustment of the system, taking the case where two elements of each unit receiving circuit are used as an example.

FIG. 8 is another diagram illustrating the spacing adjustment of the system, taking the case of using two elements of each unit receiving circuit as an example.

9 is a view for explaining a wireless communication device (magnetic heterodyne system) of the prior art.

1 is a diagram illustrating a basic configuration of a transmission and reception circuit of a wireless communication system embodying the present invention, where 1a shows a transmitting side and 1b shows a receiving side. The transmitting side is constituted by a magnetic heterodyne type or pilot insertion type millimeter wave transmission circuit, and transmits a millimeter wave modulated signal and an unmodulated signal synchronized with this phase noise component and frequency offset component. On the receiving side, the signal received by the plurality of small receiving antennas is amplified by an amplifier, then the unwanted wave components are removed by a band filter (BPF), amplified again, and then detected by a mixer circuit functioning as a quadratic circuit. do. It is synthesized in multiple stages using a plurality of synthesis circuits, and finally power-synthesized as one IF-to-synthesis output, and received by the IF-demodulation circuit.

2 is a diagram illustrating a transmitter configuration. The millimeter wave transmitter 1 inputs the IF band modulated signal output from the IF signal generator 4 to the mixer 3 to which the local oscillation signal obtained from the local oscillator 2 is input, and then the bandpass filter 5. By removing the unnecessary wave components, a radio frequency (RF) band modulated signal is obtained, but after a part of the power of the local oscillation signal used in the frequency conversion is added, the signal is amplified by the amplifier 6. It is transmitted from the transmitting antenna 7. As a result, a signal obtained by combining the RF band modulated signal with the local oscillation signal having the coherent phase noise characteristic as shown in the transmission signal spectrum of FIG. 2 is transmitted from the transmitter.

3 is a diagram illustrating a receiver configuration in which a micro planar circuit is constructed by a planar printed antenna and MMIC technology. The whole structure of a receiver is illustrated to a, and the detail of a reception antenna & detector part is illustrated to b. The signal transmitted from the transmitter is received and detected by the receiving antenna & detector 9, the output thereof is input to the IF signal demodulator 10, and the received data is demodulated.

A plurality of basic unit receiving circuits 11 are arranged in the receiving antenna & detector section 9, and each of these unit receiving circuits 11 (antennas) is arranged short enough in comparison with the wavelength of the IF band. The basic unit receiving circuit 11 is composed of a planar printed antenna 12 such as a patch antenna, an amplifier circuit 13 generated in a microplanar circuit by MMIC technology, and a mixer circuit 14 functioning as a two-pronger. . The outputs of the respective basic unit receiving circuits are power synthesized and passed to the IF signal demodulator.

Each unit receiving circuit 11 can be miniaturized using MMIC technology including an antenna, and since it does not need to have an oscillator built in, it is basically low cost. In addition, the IF signal obtained at the output of each unit receiving circuit has a phase, Since the frequency is synchronized, the synthesis diversity can be easily realized by synthesizing this. In addition, since this synthesis circuit becomes a synthesis circuit in the IF band, it does not require precision in the wavelength order of milliwaves.

It operates as a highly sensitive receiving circuit as a whole by the combined diversity effect. This is accomplished by arranging each unit receiving circuit (antenna) short enough in comparison with the wavelength of the IF band, unlike the general receiving array antenna system, without affecting the receiving beam pattern. In addition, due to the spatial diversity effect, countermeasures for signal fading peculiar to milli-wave propagation (such as a large decrease in the received signal due to the reception position) can be taken.

Hereinafter, the arrangement of each unit receiving circuit described above will be described in more detail. For example, a signal received in a millimeter wave (frequency f _rf ) communication system has a wavelength λ _rf of millimeter order. Therefore, in the case where a plurality of antennas are arranged in the receiver to receive them, and the respective outputs are considered to be synthesized, the receiver may be slightly angled with respect to the incoming wave unless the antennas are arranged at intervals sufficiently narrower than this extremely short wavelength. By only receiving in a state, a slight time difference Δτ occurs in the arrival time to each receiving antenna, which appears as a large phase difference of 2πf _rf Δτ before synthesis. In this way, since a phase difference occurs in the signal before synthesis, sufficient synthesis amplitude (synthetic power) cannot be obtained after synthesis, and the resulting gain characteristic is degraded. As an extreme case, the result is that the reception gain is not shown at all in a condition (a direction of arrival) in which phase differences before synthesis are completely eliminated from each other.

However, for example, in a system of 60 GHz band (wavelength 5 mm), it is extremely difficult to arrange the receiving antenna to be narrower than 5 mm. In response to such a problem, the system according to the present invention transmits a radio modulated signal (frequency f _rf ) and an unmodulated carrier (frequency f ₁ ) in a coherent relationship, and detects this to be a power of two. After the signals of the IF band (frequency f _ir ) are obtained, these are synthesized. Therefore, the difference Δτ of the reception arrival time, which occurs between different antennas, is generated in the same way as both the radio modulated signal and the unmodulated carrier transmitted, and as a result, the millimeter wave signal between the reception circuits originally generated is caused. The phase difference is canceled after detection. Therefore, only the phase difference 2π (f _rf -f ₁ ) Δτ = 2πf _if Δτ corresponding to the wavelength of the IF band appears after synthesis. For example, if a 600 MHz (50 cm) IF band is used in a system of 60 GHz band (5 mm wavelength), the receiving antenna spacing should be installed close enough to the IF band of 50 cm (e.g., at intervals of λ _if / 20 or less). Is easy. At this time, even if the receiver receives a signal at an angle with respect to the incoming wave, since the phase difference 2πf _if Δτ generated between the outputs of the other receiving circuits can be regarded as almost O, a good reception gain characteristic is obtained. It is possible to obtain.

(Example 1)

FIG. 4 is a diagram showing a receiving circuit (Example 1) that embodies the basic configuration shown in FIG. In the first embodiment, in synthesizing the IF output, it is possible to control the reception beam pattern by synthesizing the IF output after phase adjustment and amplitude weighting. In the example shown, each IF output is power synthesized by a synthesizer via a variable phaser and a variable attenuator. In the variable phase machine β, the phase is adjusted based on the phase control signal, and in the variable attenuator (variable ATT), the amplitude weighting is performed based on the amplitude control signal. In addition to such an analog controlled configuration, it is also possible to convert the IF output once to AD and perform digital beamforming for digital processing.

By constructing as an example, an array antenna and an adaptive array antenna capable of receiving beam waveforms capable of receiving only a signal in a certain direction of reception or vice versa or removing only an interference wave signal in a direction of reception are easily realized at a millimeter band. It becomes possible.

Usually, in order to realize an array antenna or an adaptive array antenna at millimeter waves, since the wavelength is short, extremely fine precision is required for phase control. However, with the configuration illustrated, this can be realized with the wavelength precision of the IF band. That is, since it can be realized using the adaptive array antenna technology realized in the microwave band, the cost can be easily reduced.

(Example 2)

FIG. 5 is a diagram showing a receiving circuit (Example 2) embodying the basic configuration shown in FIG. In the example shown, three or more unit receiver circuits (receive antennas) are not arranged at equal intervals, but are irregularly arranged at, for example, a fractional interval or a logarithmic distribution interval. Even when two or more receiving circuits are arranged, if the interval is correct, signal fading occurs necessarily under certain specific conditions (distance and height of the millimeter wave transmission / reception period). Therefore, using three or more, irregular intervals can prevent signal fading in most cases.

(Example 3)

FIG. 6 is a diagram showing a receiving circuit (Example 3) that embodies the basic configuration shown in FIG. The receiver configuration shown in Fig. 6A does not arrange a plurality of unit circuits only in any direction in the circuit arrangement plane, but is arranged in a direction different from this 90 ° (horizontal and vertical directions), that is, in a two-dimensional direction, respectively. Synthesize the output of. Alternatively, as shown in FIG. 6B, the cells may be arranged in a three-dimensional shape by being arranged on a surface such as a spherical shape or a cube.

Normally, multipath occurs not only in either the vertical or horizontal direction, but also in both. Therefore, by arranging as shown in the figure, multipath fading occurring in all directions can be avoided.

(Example 4)

As in the third embodiment shown in Fig. 6, the receiver configuration is arranged in two-dimensional or three-dimensional images, and the respective outputs are synthesized. On the other hand, by using the circular polarization of the antenna used in the transmission circuit, the reception diversity effect becomes effective also in all the transceiver directions.

In addition, about half of the antennas used in the receiving circuit are horizontally polarized and the remainder are vertically polarized, so that a polarization diversity effect can also be obtained.

(Example 5)

FIG. 7 is a diagram for explaining the spacing adjustment of the system, taking the case where two elements of each unit receiving circuit are used as an example. Each unit receiving circuit is fixed to a rail or the like by screwing or the like, and the interval can be changed by manual adjustment continuously or stepwise as necessary. This makes it possible to install and use radio terminals at antenna intervals suitable for the assumed communication environment.

On the other hand, Fig. 8 is a diagram for explaining the interval adjustment of the system, taking the case of using two elements of each unit receiving circuit as an example. In the example shown in FIG. 7, in addition to the structure of FIG. 7, except for one board | substrate which becomes a reference | standard among each board | substrate with which each unit reception circuit was mounted, the remaining board | substrate is attached to the rail via a moving mechanism, such as a motor, The motor is configured to be controlled by the power detection and the motor control unit. The power detection and motor control section also detects the signal output power after synthesis of the synthesis circuit and controls the motor based on the detection signal. By this control, the interval of each board | substrate is automatically adjusted so that the signal output electric power at the time of reset of an adjustment mechanism, or after synthesis | combination by a synthesis circuit may become the maximum value within the movable range of a unit receiving circuit. This makes it possible to obtain a diversity reception effect effectively under all conditions without requiring manual adjustment and with a small number of unit reception circuits.

According to the present invention, since it is a wireless communication using a magnetic heterodyne system, it is possible to use a low-cost local oscillator having a frequency unstable and a large phase noise in a transmitter, and since a receiver does not require a local oscillator itself, A low-cost wireless communication system can be constructed, and the above-described frequency instability is also canceled at the time of detection, so that a high quality signal can be transmitted (the effect of the magnetic heterodyne system).

Further, according to the present invention, the in-phase synthesis of the signals obtained from each antenna element of the array can be made at an IF band sufficiently lower than the radio frequency, so that wiring and processing precision for in-phase synthesis are not required as much, and are easily realized. It is possible.

According to the present invention, the basic unit receiving circuits can be arranged in close proximity, and the phase difference of the received signal in the RF band between each antenna element of the array is almost negligible at the detection output point of each receiving circuit. Since it is possible to achieve such a configuration, it is possible to realize a reception antenna with a high light beam that is close to the angle versus relative gain characteristic of a single-element antenna, and is very light.

Claims (10)

delete An RF band modulated signal transmitted from a transmitter and an unmodulated carrier having a coherent phase noise characteristic thereof are also received at the receiver, and a multiplier component of the RF band modulated signal and the unmodulated carrier component is generated. In the millimeter wave wireless communication method for restoring a large source signal, A receiving circuit that combines a flat-printing small receiving antenna and a micro-planar receiving circuit is used as one component, and a plurality of receiving circuits constituted as one component are shortly compared with the wavelength of the IF band, and the detected output is detected by each receiving circuit. Synthesize IF to output IF to composite output, demodulate this IF to composite output, and And three or more individual receiving circuits, wherein the intervals therebetween are arranged at irregular intervals. An RF band modulated signal transmitted from a transmitter and an unmodulated carrier having a coherent phase noise characteristic thereof are also received at the receiver, and a multiplier component of the RF band modulated signal and the unmodulated carrier component is generated. In the millimeter wave wireless communication method for restoring a large source signal, A receiving circuit that combines a flat-printing small receiving antenna and a micro-planar receiving circuit is used as one component, and a plurality of receiving circuits constituted as one component are shortly compared with the wavelength of the IF band, and the detected output is detected by each receiving circuit. Synthesize IF to output IF to composite output, demodulate this IF to composite output, and And two or more substrates each having the respective receiving circuits, wherein the spacing between these substrates is changed manually or automatically in accordance with the power of the IF-to-synthesized output. delete delete delete An RF band modulated signal transmitted from a transmitter and an unmodulated carrier having a coherent phase noise characteristic thereof are also received at the receiver, and a multiplier component of the RF band modulated signal and the unmodulated carrier component is generated. In a millimeter wave wireless communication system for recovering a large source signal, A receiving circuit that combines a flat-printing small receiving antenna and a micro-planar receiving circuit is used as one component, and a plurality of receiving circuits constituted as one component are shortly compared with the wavelength of the IF band, and the detected output is detected by each receiving circuit. A detection output synthesizing unit for synthesizing and outputting the IF-to-synthesis output; An IF signal demodulation section for inputting and demodulating the IF-to-synthesis output from the detection output synthesis section, And at least three individual receiving circuits, wherein the intervals therebetween are arranged at irregular intervals. An RF band modulated signal transmitted from a transmitter and an unmodulated carrier having a coherent phase noise characteristic thereof are also received at the receiver, and a multiplier component of the RF band modulated signal and the unmodulated carrier component is generated. In a millimeter wave wireless communication system for recovering a large source signal, A receiving circuit that combines a flat-printing small receiving antenna and a micro-planar receiving circuit is used as one component, and a plurality of receiving circuits constituted as one component are shortly compared with the wavelength of the IF band, and the detected output is detected by each receiving circuit. A detection output synthesizing unit for synthesizing and outputting the IF-to-synthesis output; An IF signal demodulation section for inputting and demodulating the IF-to-synthesis output from the detection output synthesis section, And two or more substrates each having the respective receiving circuits, wherein the spacing between these substrates is varied manually or automatically in accordance with the power of the IF-to-synthesized output. delete delete

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