JP2000353998A - Diversity receiver and diversity transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diversity receiver for maintaining a diversity effect in a simple constitution, and a diversity transmitter for maintaining the diversity effect in the simple constitution. SOLUTION: This device is provided with a plurality of antennas 11, 12, and 13 which receive transmission signals, and output reception signals, an antenna switcher 2 which sequentially switches the plurality of antennas, and outputs the reception signal, receiving circuits 3, 5, and 6 which detect the reception signal obtained through the antenna switcher 2, and convert it into a demodulation signal, and a switching controlling part 8 which controls the antenna switcher 2. The switching controlling part 8 controls the antenna switcher 2 to switch the antennas with switching frequency at a lower speed than an inverse number of a transmission band width of the reception signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity receiver and a diversity transmitter mainly used for wireless transmission of digital data signals such as voice digital data.

[0002]

2. Description of the Related Art Diversity reception is known as a means for reducing the effects of fading in wireless communication. In recent years, diversity fading has occurred in mobile phones and cellular phones, etc., in which deep fading occurs because the radio wave propagation path becomes multipath. It is widely used in mobile communication wireless devices. The most common diversity reception is spatial diversity or polarization diversity received by a plurality of antennas, and has a plurality of receiving circuits provided for each antenna. The received output is obtained by selecting and combining under conditions such as high. However, this configuration has disadvantages such as the necessity of a plurality of systems of receiving circuits as described above, which increases the cost of the apparatus. In addition, TDD (Time Di) which uses the same frequency for transmission and reception as in a personal handy phone system (PHS)
In the vision duplex (time division duplex) method, since the correlation of the propagation path characteristics in transmission and reception is strong,
Transmission diversity for transmitting using the antenna having the best reception state at the time of reception is possible. If transmission diversity is performed in the base station, a diversity effect can be obtained without performing diversity reception on the mobile station side. However, FDD (Fr (Fr
equipment Division Dup-lex,
In the case of transmission or broadcast of broadcast information which is one-way transmission from a base station, transmission diversity cannot be performed.

In recent years, wireless transmission of digital data using spread spectrum modulation by a frequency hopping method has been studied. For example, 2.4GH in Japan
Wireless local area network using z-band
The standard for “wireless LAN”) has been established by the Japan Radio Industry Association as “Low power data communication system / wireless LAN system standard RCR STD-33”, and transmission by the frequency hopping method is specified. .

In this frequency hopping system, a transmitting side and a receiving side synchronously transmit a signal while switching carrier frequencies (for example, switching as shown in FIG. 4). FIG. 4 is a timing chart showing an example in which transmission is performed while switching eight carrier frequencies. The hatched portions indicate portions where valid data cannot be transmitted due to frequency switching. In addition, the frequency hopping method encodes transmission data with an error correction code, or performs error detection to combine retransmission control when an error occurs.
A frequency diversity effect can be obtained. In other words, in an environment where the dispersion of the propagation delay time of the multipath propagation path is large and the received signal strength is non-uniform within the hopping band, even if the reception level is reduced due to fading at a certain carrier frequency, the other carrier frequencies are not used. The transmission period is often not depressed. Particularly in an environment where the fading is slow, such as a wireless LAN, a drop in the reception level over a long period of time can be avoided, and a burst error in which error bits are concentrated in a certain period can be avoided. A diversity effect can be obtained. Alternatively, when retransmission of a portion where errors frequently occur is performed in a portion of another carrier frequency, a frequency diversity effect can be obtained. Therefore, in the transmission by the frequency hopping method, if a sufficiently wide hopping frequency band can be secured, a diversity effect can be obtained by a single antenna and a single reception circuit without performing spatial diversity or polarization diversity reception.

However, when the propagation delay time of a multipath propagation path such as indoor radio wave propagation such as a wireless LAN or a cordless telephone has a small variance in the propagation delay time and the hopping bandwidth is narrow relative to the reciprocal of the dispersion, Frequency uniform fading in which the received signal strength is almost uniform in the entire hopping band often occurs. Therefore, the frequency diversity effect is lost, and the received signal quality (for example, average bit error rate) is significantly reduced due to fading. In particular, when the moving speed of the mobile station (communication terminal) is low and fading is low, such as in a cordless telephone or wireless LAN, the state of low signal quality persists for a long time. However, correct reception data cannot be obtained. Therefore, even when wireless transmission is performed by the frequency hopping method, spatial diversity reception is often used together.

FIG. 5 is a block diagram showing a conventional diversity receiver using the frequency hopping method.

In FIG. 5, reference numerals 11, 12, and 13 denote antennas; 3, an RF amplifier for amplifying RF signals received by the antennas 11, 12, and 13;
LL) circuit, which generates a local oscillation signal for frequency conversion, 5 is a mixer for converting a high-frequency signal into an intermediate frequency signal or a baseband (baseband) signal, and 6 is a mixer for the mixer 5. An amplifier / detector for amplifying the output to a required level for detection, a synthesizer 7 for synthesizing a received signal for each antenna, and a hopping controller 80. In FIG. 5, the high-frequency amplifier 3, the mixer 5, and the amplification / detector 6 constitute a receiving circuit. The high-frequency amplifier 3 has a low noise level in order to increase the receiving sensitivity. Further, as a method of combining in the combiner 7, for example, selective combining for selectively outputting a signal corresponding to an antenna having the highest received signal strength (hereinafter referred to as “RSSI”), or receiving a signal for each antenna into RSSI The maximum ratio combining that weights and adds according to is used. further,
The hopping control unit 80 sets a frequency switching signal synchronized with the switching of the transmission frequency (hopping) in the frequency synthesizer 4.

The operation of the conventional diversity receiver configured as described above will be described.

The high-frequency signals received by the antennas 11, 12, and 13 are processed by a high-frequency amplifier 3, a mixer 5, and an amplifying / detector 6, respectively, and are converted into baseband signals. At this time, the hopping control unit 80 synchronizes with the switching of the transmission frequency of the partner station, and
The reception frequency is switched by switching the local oscillation frequency. Specifically, first, the hopping control unit 80
The reception is started asynchronously according to the hopping frequency switching pattern stored in. Then, while shifting the switching phase of the switching pattern, the average RSSI
Find the phase that maximizes and fix it. Thereafter, a known data position called a unique word included in a specific position of the received data is monitored, and a tracking operation is performed so that the data can be received at a predetermined position.

If the tracking operation of the frequency hopping is performed well, the carrier frequency of the intermediate frequency signal or the baseband signal output from the mixer 5 is kept constant or zero, respectively. The signal processing operates similarly to a diversity receiver for wireless communication without using spread spectrum. That is, each antenna 11,
The detected baseband signal or demodulated data is synthesized and selected according to the RSSIs in 12 and 13. Therefore, the RSS at any antenna due to fading
Even when I becomes low, a signal corresponding to another antenna that is receiving well is output from the combiner 7 and can be received with good signal quality.

FIG. 6 is a block diagram showing a diversity receiver and a diversity transmitter using a frequency hopping scheme based on TDD.

In FIG. 6, antennas 11, 12, 1
3, high frequency amplifier 3, frequency synthesizer 4, mixer 5, amplifier / detector 6, synthesizer 7, hopping controller 80
Are the same as those in FIG. 5, and therefore, are denoted by the same reference numerals and description thereof will be omitted. 9 is a transmission circuit for outputting a transmission signal modulated in accordance with transmission data, 22 is a transmission / reception switch for connecting an antenna to the transmission circuit 9 or the high-frequency amplifier 3 which is an input stage of the reception circuit according to a transmission / reception period, Reference numeral 23 denotes a transmission antenna switch for selecting an antenna at the time of transmission. The transmission circuit 9 is supplied from the frequency synthesizer 4 with a local oscillation signal corresponding to the transmission frequency.

The operation of the conventional diversity receiver and diversity transmitter configured as described above will be described as a reception period and a transmission period.

First, during the reception period, the transmission / reception switch 22 is connected to the high-frequency amplifier 3 side. Therefore,
The high frequency signals received by the antennas 11, 12, 13 are:
The signal is processed by the high-frequency amplifier 3, the mixer 5, and the amplifying / detector 6, and is converted into a baseband signal. At this time, the hopping control unit 80 controls the frequency synthesizer 4 in synchronization with the switching of the transmission frequency of the partner station to switch the reception frequency, similarly to the diversity receiver of FIG. 5, and performs the same operation as the diversity receiver of FIG. The operation is performed.

Next, at the time of transmission, the transmission / reception changeover switch 22 is connected to the transmission circuit 9 side, and the transmission signal from the transmission circuit 9 is transmitted from the antenna 11, 12 or 13 via the transmission antenna switch 23. The transmission antenna switch 23 is controlled by the combiner 7 and is connected to the antenna having the best reception state in the immediately preceding reception period, for example, the RSSI having the maximum. At this time, the hopping control unit 80 controls the frequency synthesizer 4 and switches the transmission frequency according to a predetermined hopping pattern, similarly to the conventional frequency hopping type transmitter.

With the above operations, diversity reception and diversity transmission have been performed.

[0017]

However, in the above-mentioned conventional diversity receiver and transmitter, a plurality of receiving circuits 3, 5, 6 and a combiner 7 provided for each antenna are required, and the configuration is complicated. Had the problem of becoming In particular, in order to obtain a large diversity gain, it is necessary to increase the number of antennas, that is, the number of diversity branches, and there is a problem that the configuration is further complicated.

In the diversity receiver and the diversity transmitter, it is required to maintain the diversity effect with a simple configuration.

An object of the present invention is to provide a diversity receiver capable of maintaining a diversity effect with a simple configuration and a diversity transmitter capable of maintaining a diversity effect with a simple configuration.

[0020]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a diversity receiver according to the present invention includes a plurality of antennas for receiving a transmission signal and outputting a reception signal, and sequentially switching the plurality of antennas to receive a reception signal. An antenna switch for outputting, a reception circuit for detecting a received signal obtained through the antenna switch and converting the signal into a demodulated signal, and a switch control unit for controlling the antenna switch; The antenna switch is controlled so that the antenna is switched at a switching frequency lower than the reciprocal of the signal transmission bandwidth.

Thus, a diversity receiver that can maintain the diversity effect with a simple configuration can be obtained.

In order to solve the above problems, a diversity transmitter according to the present invention comprises: a plurality of antennas; an antenna switching device for sequentially switching and connecting the plurality of antennas; a transmission circuit for outputting a transmission signal to the antenna switching device; A switching control unit for controlling the antenna switching unit, wherein the switching control unit is configured to control the antenna switching unit so as to switch the antenna at a switching frequency lower than the reciprocal of the transmission bandwidth of the transmission signal. .

As a result, a diversity transmitter which can maintain the diversity effect with a simple configuration can be obtained.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A diversity receiver according to a first aspect of the present invention includes a plurality of antennas for receiving a transmission signal and outputting a reception signal, and an antenna for outputting a reception signal by sequentially switching the plurality of antennas. A switching circuit, a receiving circuit that detects a received signal obtained through the antenna switching device and converts the received signal into a demodulated signal, and a switching control unit that controls the antenna switching device, wherein the switching control unit transmits the received signal. The antenna switching device is controlled so that the antenna is switched at a switching frequency lower than the reciprocal of the bandwidth.

With this configuration, even if the reception level drops at a specific antenna due to fading,
During the period of reception by another antenna due to the switching of antennas, the probability of good reception is high, the diversity effect is maintained, and good transmission quality is obtained.

According to a second aspect of the present invention, there is provided a diversity receiver comprising: a plurality of antennas for receiving a transmission signal according to a frequency hopping method and outputting a received signal; and an antenna switching unit for sequentially switching the plurality of antennas and outputting a received signal. A receiving circuit that detects a received signal obtained through the antenna switching device and converts the received signal into a demodulated signal, and a switching control unit that controls the antenna switching device, wherein the switching control unit synchronizes the antenna with frequency hopping. The antenna switching device is controlled so as to switch between them.

With this configuration, even if the reception level drops at any hopping frequency at a specific antenna due to frequency uniform fading, the probability of good reception during the period of reception at another antenna by switching antennas is improved. , The diversity effect is maintained, and good transmission quality is obtained.

A diversity receiver according to a third aspect is the diversity receiver according to the second aspect,
The number of the plurality of antennas is assumed to be relatively prime to the number of carrier frequencies of the frequency hopping system.

According to this configuration, the number of combinations of the frequency and the antenna at the time of hopping increases, and the number of equivalent diversity branches increases in the propagation environment of the frequency selective fading, which has the effect of improving the diversity effect.

According to a fourth aspect of the present invention, there is provided a diversity transmitter comprising: a plurality of antennas; an antenna switch for sequentially switching and connecting the plurality of antennas; a transmission circuit for outputting a transmission signal to the antenna switch; A switching control unit for controlling the antenna switching unit so as to switch the antenna at a switching frequency lower than the reciprocal of the transmission bandwidth of the transmission signal.

With this configuration, even when the reception level of the other station drops when a specific antenna is transmitted due to fading, the probability of good transmission is high during the period of transmission by another antenna by switching antennas. This has the effect that the diversity effect is maintained and good transmission quality is obtained. In addition, a receiving station such as a mobile station can obtain a diversity effect without having a plurality of antennas and receiving circuits for diversity reception, and has an effect of reducing the size and cost of a wireless device of a mobile station.

According to a fifth aspect of the present invention, there is provided a diversity transmitter, a plurality of antennas for transmitting a transmission signal by a frequency hopping method, an antenna switching device for sequentially switching and connecting the plurality of antennas, and outputting a transmission signal to the antenna switching device. And a switching control unit for controlling the antenna switching unit, wherein the switching control unit switches the antennas in synchronization with the frequency hopping at the same or low switching frequency as the frequency hopping interval. Is to control the vessel.

With this configuration, even when the reception level of the partner station drops at any hopping frequency due to uniform frequency fading and transmission by a specific antenna, the period of transmission by another antenna by switching antennas Has the effect that the probability of good reception at the partner station is high, the diversity effect is maintained, and good transmission quality is obtained. Also, on the receiving station side such as a mobile station, a diversity effect can be obtained without having a plurality of antennas and receiving circuits for diversity reception,
This has the effect of reducing the size and cost of the wireless device of the mobile station.

The diversity transmitter according to claim 6 is the diversity transmitter according to claim 5,
The number of the plurality of antennas is assumed to be relatively prime to the number of carrier frequencies of the frequency hopping system.

With this configuration, the number of combinations of the frequency and the antenna at the time of hopping is increased, and the number of equivalent diversity branches is increased in the propagation environment of frequency selective fading, thereby having the effect of improving the diversity effect.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment 1) FIG. 1 is a block diagram showing a diversity receiver according to Embodiment 1 of the present invention, and shows a diversity receiver using a frequency hopping method.

In FIG. 1, reference numerals 11, 12, and 13 denote antennas, reference numeral 2 denotes an antenna switch for sequentially connecting one of the antennas 11, 12, and 13, and reference numeral 3 denotes antennas 11 to 1.
A high-frequency amplifier for amplifying the high-frequency signal received at 3;
Is a frequency synthesizer for generating a local oscillation signal for frequency conversion, 5 is a mixer for converting a high-frequency signal into an intermediate frequency signal or a baseband signal, and 6 is a mixer 5 Amplifier / detector that amplifies the output of the amplifier to a required level and detects it.
Sets the frequency switching signal a synchronized with the switching of the transmission frequency (hopping) in the frequency synthesizer 4, switches the frequency of the frequency synthesizer 4, and switches the receiving antenna by controlling the antenna switching unit 2 with the antenna switching signal b. A hopping control unit as a switching control unit. In FIG. 1, antenna 1
1 to 13, the high-frequency amplifier 3, the frequency synthesizer 4, the mixer 5, and the amplifying / detecting device 6 are the same as those in FIGS. 5 and 6, and are denoted by the same reference numerals. Here, the antennas 11 to
Numeral 13 denotes a branch of three branches, a branch of polarization or directivity diversity, and a high-frequency amplifier 3 of low noise is used in order to increase the reception sensitivity. The above configuration is the same as a normal frequency hopping type receiver if the antenna switching unit 2 is removed and reception is performed with a single antenna.

The operation of the diversity receiver configured as described above will be described with reference to FIG. FIG.
FIG. 3 is a timing chart showing a combination of hopping carrier frequencies (carrier frequencies of the frequency hopping method) and antennas 11 to 13.

The high level received by the antennas 11, 12, 13
One of the frequency signals is
By selecting and connecting the antenna, a high-frequency amplifier
3, processed by the mixer 5 and the amplification / detector 6,
It is converted to a band signal. At this time, hopping control unit
8, the diversity of the conventional frequency hopping method
As with the receiver, switching and synchronizing the transmission frequency of the partner station
To control the frequency synthesizer 4 and adjust the local oscillation frequency.
By switching, the reception frequency is switched. Follow
And the intermediate frequency signal or the base
The carrier frequency of the command signal is kept constant or zero, respectively.
Dripping. The hopping control unit 8 switches the reception frequency.
At the same time, control the antenna switch 2 to turn the antennas in order.
Next switch. For example, the number of carrier frequencies for hopping
(The number of frequency hops) is f₁, F_Two, F _Three, ..., f₈Of 8
Hopping carrier frequency, as shown in FIG.
And the antenna are switched in sequence, and the frequency
24 totals, which is the least common multiple of the number of tips 8 and the number of antennas 3
It switches according to the combination of the lights. Frequency and
When the antenna is switched, the conventional antenna described with reference to FIG.
As in the case of the wave number hopping method, the hatched portion in FIG.
There is a period during which valid data cannot be received due to switching
The length of the signal in the intermediate frequency amplifier or demodulator of the receiver.
Reciprocal of the passband of the filter in the
Is proportional to the reciprocal of the bandwidth. Therefore, the frequency and
The switching frequency of the antenna is longer than the reciprocal of the above bandwidth
It is performed every hour. If the slow frequency
Fading (uniform frequency fading means transmission band
Area, that is,
Phase and amplitude over the available frequency range
Equal (meaning that they are uniformly flat) occurs,
RSSI at antenna 11 is low and transmission errors occur frequently.
Different carrier frequencies and different locations.
Good for other antennas 12 and 13
Has a high probability of receiving. Therefore, using error correction code
Or correct data reception by controlling data retransmission.
Data can be obtained. In addition, frequency-selective
Normal frequency hopping
Frequency diversity effect similar to that of
Therefore, the transmission characteristics are further improved. As in this embodiment
The relationship between the number of frequency hops and the number of antennas
If you choose, the combination of more frequencies and antennas
And the equivalent number of diversity branches is large.
You.

Although the number of frequency hops is set to 8 in the present embodiment, even when the number of hops is 0, that is, in the case of burst transmission without hopping, the present apparatus works effectively in maintaining the diversity effect. . In this case, the same effect as in the case where the uniform frequency fading described in the present embodiment occurs can be obtained in any of the uniform frequency fading and the frequency selective fading. Although the number of antennas is three in the present embodiment, the diversity effect improves as the number of antennas increases as in the case of normal diversity.

As described above, according to the present embodiment, a plurality of antennas 11 to 13, an antenna switch 2 for sequentially switching the plurality of antennas 11 to 13 and outputting a reception signal, and an antenna switch 2 Receiving circuits 3, 5, 6 for detecting the received signal obtained by the conversion and converting it into a demodulated signal;
A switching control unit 8 for controlling the antenna switching unit 2 is provided. The switching control unit 8 controls the antenna switching unit 2 so as to switch the antennas 11 to 13 in synchronization with frequency hopping. Even if the reception level drops at any hopping frequency at a specific antenna due to fading, the switching of antennas increases the probability of good reception during the period of reception at another antenna. The diversity effect can be maintained with a simple configuration of a circuit, and good transmission quality can be obtained.

Even when the number of frequency hops is 0, even when the reception level at a specific antenna drops due to fading, the probability of good reception increases during the period of reception at another antenna by switching antennas. The diversity effect can be maintained with a simple configuration of one system of receiving circuit, and good transmission quality can be obtained.

(Embodiment 2) FIG. 3 is a block diagram showing a diversity receiver and a diversity transmitter (ie, diversity transceiver) according to a second embodiment of the present invention. 1 shows a diversity transmitter.

In FIG. 3, antennas 11, 12, 1
3, the antenna switch 2, the high-frequency amplifier 3, the frequency synthesizer 4, the mixer 5, the amplifying / detector 6, and the hopping controller 8 are the same as those in FIG. Reference numeral 9 denotes a transmission circuit for outputting a transmission signal modulated according to transmission data, and reference numeral 21 denotes a transmission / reception switch for connecting an antenna to the transmission circuit 9 or the high-frequency amplifier 3 which is an input stage of the reception circuit according to a transmission / reception period. is there. The transmission circuit 9 is supplied with a local oscillation signal corresponding to the transmission frequency from the frequency synthesizer 4.

The operation of the diversity receiver and the diversity transmitter configured as described above will be described as a reception period and a transmission period.

First, during the reception period, the transmission / reception switch 21 is connected to the high frequency amplifier 3 side. Therefore,
The high frequency signals received by the antennas 11, 12, 13 are:
The signal is processed by the high-frequency amplifier 3, the mixer 5, and the amplifier / detector 6 (receiving circuit) and converted into a baseband signal.
At this time, the hopping control unit 8 controls the frequency synthesizer 4 in synchronization with the switching of the transmission frequency of the partner station, and switches the reception frequency, similarly to the diversity receivers of the related art and the first embodiment. The hopping control unit 8
At the same time as the reception frequency is switched, the antenna switching unit 2 is controlled to sequentially switch the antennas, and the same reception operation as in the first embodiment is performed.

Next, in the transmission period, the transmission / reception changeover switch 21 is connected to the transmission circuit 9 side, and the transmission signal from the transmission circuit 9 is transmitted from the antenna 11, 12 or 13 via the antenna switch 2. At this time, the hopping control unit 8 controls the frequency synthesizer 4 with the frequency switching signal a, and switches the transmission frequency according to a predetermined hopping pattern, similarly to the conventional frequency hopping type transmitter. Hopping controller 8
Controls the antenna switching unit 2 simultaneously with the switching of the transmission frequency to sequentially switch the transmission antenna. When the antennas are sequentially switched for transmission and reception in this manner, the same effects as in the first embodiment can be obtained during reception. Further, at the time of transmission, R
If the SSI is low and transmission errors occur frequently, there is a high probability that the other antennas 12 and 13 can communicate well. Therefore, by using an error correction code or performing retransmission control of data, correct received data can be obtained for both transmission and reception. That is, a diversity effect can be obtained for both transmission and reception. In particular, when the present embodiment is applied to a base station device or a base unit of a cordless telephone, a diversity effect (transmission diversity effect) can be obtained without having a plurality of antennas and receiving circuits for diversity reception on the mobile station side. The wireless device of the mobile station can be manufactured small and inexpensively.

In the case of FDD, the operation is exactly the same if an antenna duplexer (duplexer) composed of a band-pass filter is used instead of the transmission / reception switch 21. In addition, the switching operation of the transmitting antenna does not use any information such as RSSI obtained at the time of reception, and is simple control in which the antennas are simply sequentially switched.
D also allows transmission diversity. Also,
Although the number of frequency hops is set to 8 in the present embodiment,
As in the first embodiment, even in the case of burst transmission without hopping, the present device works effectively in maintaining the diversity effect. Further, in the present embodiment, the number of antennas is three, but the diversity effect is improved as the number of antennas is increased as in the case of normal diversity.

As described above, according to the present embodiment, a plurality of antennas 11 to 13, an antenna switch 2 for sequentially switching and connecting a plurality of antennas 11 to 13, and a transmission signal output to antenna switch 2 A transmitting circuit 9 to perform
And a switching control unit for controlling the antenna switching unit. The switching control unit controls the antenna switching unit to switch the antenna in synchronization with the frequency hopping at a switching frequency equal to or lower than the frequency hopping interval. By controlling, even if the reception level of the partner station drops at any hopping frequency due to frequency uniform fading and transmission at a specific antenna, transmission is performed at another antenna by switching the antenna. During the period, the probability of good reception at the partner station increases, so that the diversity effect can be maintained with a simple configuration of the transmission circuit, and good transmission quality can be obtained. Also, the receiving station such as a mobile station can obtain a diversity effect without having a plurality of antennas and receiving circuits for diversity reception, and can reduce the size and cost of the wireless device of the mobile station.

Even when the number of frequency hops is 0, even when the reception level of the partner station drops when a specific antenna is transmitted due to fading, the period for transmitting with another antenna is good by switching the antenna. The probability of transmission is increased, the diversity effect can be maintained with a simple configuration of a transmission circuit, and good transmission quality can be obtained.

[0052]

As described above, according to the diversity receiver of the first aspect of the present invention, a plurality of antennas for receiving a transmission signal and outputting a reception signal, and a plurality of antennas are sequentially switched for reception. An antenna switching unit that outputs a signal, a reception circuit that detects a received signal obtained through the antenna switching unit and converts the signal into a demodulated signal, and a switching control unit that controls the antenna switching unit. By controlling the antenna switch so that the antenna is switched at a switching frequency lower than the reciprocal of the transmission bandwidth of the received signal, even if the reception level drops at a specific antenna due to fading, other antennas are switched by switching the antenna. Since the probability of good reception is high during the period of reception by the antenna, it is simple to use a single-system reception circuit. Composed can maintain diversity effect, advantageous effect is obtained that it is possible to obtain good transmission quality.

According to the diversity receiver of the present invention, a plurality of antennas for receiving a transmission signal by the frequency hopping method and outputting a reception signal, and an antenna switching for sequentially switching the plurality of antennas and outputting a reception signal And a receiving circuit for detecting a received signal obtained through the antenna switching device and converting it to a demodulated signal, and a switching control unit for controlling the antenna switching device. The switching control unit synchronizes with frequency hopping. Even if the reception level drops at any hopping frequency in a specific antenna by frequency uniform fading by controlling the antenna switching device to switch the antenna by switching the antenna, reception by another antenna is performed by switching the antenna. During the period, the probability of good reception increases, so one system Diversity effect with a simple structure that the receiving circuit can be maintained, advantageous effect is obtained that it is possible to obtain good transmission quality.

According to the diversity receiver set forth in claim 3, in the diversity receiver set forth in claim 2, the number of the plurality of antennas is relatively prime to the number of carrier frequencies in the frequency hopping system. As a result, the number of combinations of frequency and antenna at the time of hopping increases, so that the number of equivalent diversity branches increases in the propagation environment of frequency selective fading, and the advantageous effect that the diversity effect can be improved can be obtained. Can be

According to the diversity transmitter of the present invention, a plurality of antennas, an antenna switching device for sequentially switching and connecting the plurality of antennas, a transmission circuit for outputting a transmission signal to the antenna switching device, and an antenna switching device A switching control unit that controls the antenna switching unit, wherein the switching control unit controls the antenna switching unit to switch the antenna at a switching frequency lower than the reciprocal of the transmission bandwidth of the transmission signal, thereby specifying the antenna by fading. Even if the receiving level of the other station drops when the antenna is transmitted, the probability of successful transmission increases during the period of transmission by another antenna due to antenna switching. Advantageous effect that good transmission quality can be obtained. Obtained. In addition, since a diversity effect can be obtained without having a plurality of antennas and receiving circuits for diversity reception on the receiving station side such as a mobile station, it is possible to reduce the size and cost of the wireless device of the mobile station. The effect is obtained.

According to the diversity transmitter of the present invention, a plurality of antennas for transmitting a transmission signal by the frequency hopping method, an antenna switching device for sequentially switching and connecting the plurality of antennas, and a transmission signal for the antenna switching device. And a switching control unit that controls the antenna switching unit. The switching control unit includes:
By controlling the antenna switching unit to switch the antenna in synchronization with the frequency hopping at the same or low switching frequency as the frequency hopping interval, when transmitting with a specific antenna by frequency uniform fading, Even if the reception level of the partner station drops even at the hopping frequency, the probability of good reception at the partner station increases during the period of transmission with another antenna by switching antennas, so the diversity effect can be achieved with a simple configuration of the transmission circuit. , And an advantageous effect that good transmission quality can be obtained. In addition, since a diversity effect can be obtained without having a plurality of antennas and receiving circuits for diversity reception on the receiving station side such as a mobile station, it is possible to reduce the size and cost of the wireless device of the mobile station. The effect is obtained.

According to the diversity transmitter set forth in claim 6, in the diversity transmitter set forth in claim 5, the number of the plurality of antennas is disjoint from the number of carrier frequencies in the frequency hopping system. Therefore, the number of combinations of the frequency and the antenna at the time of hopping increases, so that it is possible to increase the equivalent number of diversity branches in the propagation environment of frequency selective fading, and to improve the diversity effect. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a diversity receiver according to a first embodiment of the present invention.

FIG. 2 is a timing diagram showing a combination of a hopping carrier frequency and an antenna.

FIG. 3 is a block diagram showing a diversity receiver and a diversity transmitter according to a second embodiment of the present invention.

FIG. 4 is a timing chart showing an example in which transmission is performed while switching eight carrier frequencies.

FIG. 5 is a block diagram showing a conventional diversity receiver using a frequency hopping method.

FIG. 6 is a block diagram illustrating a diversity receiver and a diversity transmitter using a frequency hopping scheme based on TDD.

[Explanation of symbols]

 Reference Signs List 2 antenna switcher 3 high frequency amplifier 4 frequency synthesizer (PLL synthesizer) 5 mixer 6 amplifying / detector 8 hopping control unit (switching control unit) 9 transmitting circuit 11, 12, 13 antenna 21 transmission / reception switching switch

Claims (6)

[Claims] A plurality of antennas for receiving a transmission signal and outputting a reception signal; an antenna switch for sequentially switching the plurality of antennas to output the reception signal; and an antenna switch obtained via the antenna switch. A receiving circuit that detects a received signal and converts it into a demodulated signal; and a switching control unit that controls the antenna switching unit, wherein the switching control unit performs switching at a speed lower than the reciprocal of the transmission bandwidth of the received signal. A diversity receiver that controls the antenna switching device to switch the antenna at a frequency. A plurality of antennas for receiving a transmission signal based on a frequency hopping method and outputting a reception signal; an antenna switching device for sequentially switching the plurality of antennas and outputting the reception signal; And a switching control unit for controlling the antenna switching unit, wherein the switching control unit switches the antenna in synchronization with frequency hopping. A diversity receiver for controlling the antenna switching device as described above. 3. The diversity receiver according to claim 2, wherein the number of said plurality of antennas is relatively prime to the number of carrier frequencies in a frequency hopping system. 4. A plurality of antennas, an antenna switching unit for sequentially switching and connecting the plurality of antennas, a transmission circuit for outputting a transmission signal to the antenna switching unit, and a switching control unit for controlling the antenna switching unit. A diversity transmitter, wherein the switching control unit controls the antenna switching unit to switch the antenna at a switching frequency lower than a reciprocal of a transmission bandwidth of the transmission signal. 5. A plurality of antennas for transmitting a transmission signal by a frequency hopping method, an antenna switch for sequentially switching and connecting the plurality of antennas, a transmission circuit for outputting a transmission signal to the antenna switch, and the antenna A switching control unit for controlling a switching unit, wherein the switching control unit controls the antenna switching unit to switch the antenna in synchronization with frequency hopping by a switching frequency equal to or lower than a frequency hopping interval. A diversity transmitter. 6. The diversity transmitter according to claim 5, wherein the number of the plurality of antennas is relatively prime to the number of carrier frequencies of the frequency hopping scheme.