JPH066275A - Diversity radio equipment - Google Patents

Abstract

PURPOSE:To obtain satisfactory receiving diversity and transmitting diversity by stopping a signal outputted from a transmitting means to an antenna side at the time of receiving a signal. CONSTITUTION:A transmitting signal outputted from an IF/RF transmitting part 68 is inputted to both of high frequency switches 721, 722 through a hybrid (H) 11. When a transmission timing signal is inputted from a burst generating part 66, a switch control part 12 generates a control signal corresponding to an output signal of a level comparing part 65, and switches a high frequency switch connected to an antenna whose receiving level is larger to a transmitting side Ta (Tb). In this case, between a local oscillator 71 and the IF/RF transmitting part 68, a high frequency switch 13 is arranged, and the switch control part 12 executes control for turning on the high frequency switch 13 by a timing for outputting the control signal to one of the high frequency switches 721, 722.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses TDMA-TDD in which signals in the same frequency band are used as transmission / reception channels in a time division manner.
The present invention relates to a diversity radio device that shares a transmission / reception antenna in a digital wireless communication system.

[0002]

2. Description of the Related Art As shown in FIG. 5, the TDMA-TDD system has, for example, four transmission time slots and four reception time slots in a frame of a multiplexing number of 8 and one carrier forms four channels. It is a time-division multiple access method for performing communication by performing communication. In such a radio device compatible with the TDMA-TDD system, it is indispensable to prevent the transmission signal from sneaking into the reception side when the transmission / reception antenna is shared. Therefore, in the related art, high frequency is applied to the transmission side and the reception side. A switch (RF switch) was used.

On the other hand, in the TDMA-TDD system, the transmission wave and the reception wave are carrier waves having the same frequency. Therefore, when there is a temporal correlation between the transmission timing and the reception timing,
It can be considered that the propagation conditions from the reception of the signal to the transmission thereof are equal. Therefore, it becomes possible to perform transmission diversity in which a signal is transmitted from the antenna having a higher reception level when the reception diversity is performed.

FIG. 6 is a block diagram showing the configuration of a conventional TDMA-TDD radio apparatus which performs transmission / reception diversity. In the figure, two systems of RF / IF receivers 62 ₁ and 62 ₂ and demodulators 63 ₁ and 63 ₂ that perform frequency conversion of received signals are provided corresponding to the respective antennas 61 ₁ and 61 ₂ , and demodulated there. The demodulated signal is input to the selection unit 64. Further, each of the demodulation units 63 ₁ and 63 ₂ detects the reception level (RSSI) of each system and sends it to the level comparison unit 65, and the level comparison unit 65 outputs the demodulation signal having the larger reception level. Then, the selection unit 64 is controlled to perform reception diversity.

On the other hand, the transmission signal is input to the modulator 67 at a predetermined timing via the burst generator 66. The modulated signal output from the modulator 67 is frequency-converted by the IF / RF transmitter 68 and input to the high frequency switch (SW) 69. The switch control unit 70 includes the burst generation unit 6
When 6 outputs the transmission timing signal (“0”),
A control signal for selecting the demodulation signal having the larger reception level determined by the level comparison unit 65 is output to the high frequency switch 69. The high frequency switch 69 sends the modulated signal, which has been frequency-converted according to the control signal, to the antenna selected by the receive diversity to perform the transmit diversity.

Here, the local oscillator 71 sends the local oscillation signal used for the frequency conversion to the RF / IF receiving units 62 ₁ and 62 ₂ and the IF / RF transmitting unit 68. Also,
The high frequency switches (SW) 72 ₁ and 72 ₂ receive the signals received by the antennas 61 ₁ and 61 ₂ from the RF / IF receiver 6 respectively.
The configuration is such that transmission / reception switching is performed in which the signal input to the IF / RF transmission unit 68 is output to the antennas 2 ₁ and 62 _2, and transmission / reception switching is performed only when the transmission timing signal is output from the burst generation unit 66. Connected to sender T
(High-frequency switch 69, IF / RF transmitter 68, modulator 67), and the others are connected to receivers R (RF / IF receivers 62 ₁ , 62 ₂ , demodulators 63 ₁ , 63 ₂ ).

[0007]

By the way, in the conventional high-frequency switches 72 ₁ and 72 ₂ shown in FIG.
It is designed to attenuate the sneak of the transmitted wave (local oscillation signal) by connecting to the receiving side except when transmitting. However, if the transmitting output is very large and the receiving level is very small, structurally It was difficult to obtain sufficient isolation. Therefore, TDMA-TDD
In the wireless device that adopts the method, there is a restriction on the difference between the maximum transmission output and the minimum reception level.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a TDMA-TDD system radio which is capable of avoiding the influence of transmission output and performing good reception diversity and transmission diversity.

[0009]

According to the present invention, there are provided a plurality of antennas, a reception means for performing reception diversity using the plurality of antennas, and a reception diversity selected 1
And a high-frequency switch means for connecting the respective antennas and the receiving means at the time of signal reception and for connecting the transmitting means and the respective antennas at the time of signal transmission. In a diversity radio that performs transmission and reception by time-sharing a frequency band of one carrier wave on a plurality of transmission and reception channels, a local oscillator that outputs a local oscillation signal used for frequency conversion of a transmission signal by the transmission means, and the transmission means. It is characterized in that it comprises switch means which is arranged between the two and which allows the local oscillation signal to be inputted to the transmitting means only at the time of signal transmission.

[0010]

According to the present invention, the local oscillation signal is given to the transmitting means only when the signal is transmitted, the frequency is converted into the signal in the radio frequency band, and the signal is transmitted from the antenna designated by the transmission diversity.
On the other hand, when the signal is received, the local oscillation signal is not given to the transmitting means, so that the signal output from the transmitting means to the antenna side can be completely stopped.

Therefore, even if the high-frequency switch for switching the connection between the receiving means or the transmitting means and the antenna cannot be sufficiently isolated, the transmitted wave (local oscillation signal) wraps around to the receiving means side when the signal is received. Can be avoided.

The transmission / reception isolation required of the high frequency switch is given by (transmission level)-(reception level) + (co-channel interference). For example, if the transmission level is -10 dB, the reception level is -80 dB, and the co-channel interference is 20 dB, the transmission / reception isolation of 90 dB or more is required.
The diversity radio of the present invention can easily meet the demand.

[0013]

1 is a block diagram showing the configuration of a first embodiment of the present invention. In the figure, antennas 61 ₁ and 61
_2, the high frequency switch 72 _1, 72 _2, RF / IF receiver section 62 ₁ a receiving means for receiving diversity, 6
2 ₂ , demodulation units 63 ₁ and 63 ₂ , a selection unit 64 and a level comparison unit 65, a burst generation unit 66 as a transmission means for performing transmission diversity, a modulation unit 67 and an IF / RF transmission unit 68, and a local oscillator 71. This is similar to the conventional configuration shown in FIG.

In this embodiment, the IF / RF transmitter 6
The transmission signal output from 8 is the hybrid (H) 11
Is input to both high frequency switches 72 ₁ and 72 ₂ . When the transmission timing signal is input from the burst generation unit 66, the switch control unit 12 generates a control signal according to the output signal of the level comparison unit 65 and is a high frequency switch connected to the antenna with the higher reception level. To the transmitting side (Ta or Tb). By performing such switch control, transmission diversity and corresponding transmission / reception switching of the high frequency switch can be realized at the same time.

The feature of the present invention is that the high frequency switch 13 is arranged between the local oscillator 71 and the IF / RF transmitter 68 in the present embodiment, and the switch controller 12 is provided.
Is configured to perform control to turn on the high frequency switch 13 at the timing of outputting the control signal to either of the high frequency switches 72 ₁ and 72 ₂ .

The transmission diversity control timing will be described below with reference to FIG. The level comparison unit 65
The reception levels RSSI1 and RSSI2 of the signals received from the antennas 61 ₁ and 61 ₂ are converted into demodulation units 63 ₁ and 63 _{2, respectively.}
, The receiving system having the larger receiving level is determined at the end of the receiving time frame. In FIG. 2, the reception timing R1
However, since RSSI2 is larger, transmission diversity using the antenna 61 ₂ for transmission is performed until re-determination is performed at the next reception timing R2.

When the burst generator 66 outputs the transmission timing signals (T1, T2, T3, ...), the switch controller 12 determines the antenna selected by the receive diversity from the detection result of the level comparator 65, and responds. A control signal is sent to the high frequency switch to switch the connection destination of the antenna to the transmission side (transmission diversity), and the high frequency switch 13 is turned on. In FIG. 2, at the transmission timing T1, the high frequency switch 72 ₂ is controlled to be connected to the transmission side Tb, and the high frequency switch 13 is turned on. At the transmission timing T2, the high frequency switch 72 ₁ is controlled to be connected to the transmission side Ta, and the high frequency switch 13
Turn on.

Therefore, for example, the transmission signal output from the burst generation unit 66 at the transmission timing T1 is modulated by the modulation unit 67 and further converted into a radio frequency signal by the IF / RF transmission unit 68, and the hybrid 11 and the corresponding high frequency signal. Through the switch 72 ₂ , the corresponding antenna 61
Sent from ₂ .

On the other hand, reception timings R1, R2, R3
In ... Because the transmission timing signal from the burst generator 66 is not output, the high-frequency switch 72 _1, 72 ₂ is connected to the receiver R, further high-frequency switch 13 is turned off. Therefore, the local oscillation signal is transmitted to the IF / RF transmitter 6
8 is no longer applied to the transmission signal, and the transmission wave from the IF / RF transmission unit 68 can be stopped. In other words, it prevents the transmission wave at the time of reception around to the receiving system via the high-frequency switch 72 _1, 72 _2, even when using the transceiver same carrier in TDMA-TDD system, good reception characteristics while enabling transmission diversity Can be realized.

FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention. In this embodiment, the structure of the high-frequency switch for switching between transmission and reception and transmission diversity corresponds to the conventional structure shown in FIG. 5, and will be described in exactly the same manner.

The feature of this embodiment is that in such a configuration, the local oscillator 71 and the IF / RF transmitter 68 are provided.
The high-frequency switch 13 is arranged between and, and the transmission timing signal output from the burst generator 66 is used as its on / off control signal. The operation is similar to that of the first embodiment.

FIG. 4 is a circuit configuration diagram of a diversity radio device corresponding to the second embodiment of the present invention. In the figure, antennas 61 ₁ and 61 ₂ and high frequency switches 13, 69 and 72
₁ , 72 ₂ , the selection unit 64, the level comparison unit 65, the burst generation unit 66, the modulation unit 67, and the switch control unit 70 shown in FIG.
It corresponds directly to the configuration of the second embodiment shown in FIG.

Reception frequency band pass filter (RFBP
F) 31 ₁ , 31 ₂ , reception RF amplifiers 32 ₁ , 32 ₂ ,
The mixers 33 ₁ and 33 ₂ and the intermediate frequency band pass filters (IFBPF) 34 ₁ and 34 ₂ are provided in the RF / IF receiving unit 6.
Corresponding to 2 ₁ and 62 _2, it realizes a function of converting a signal received by the antenna into an intermediate frequency signal.

Limiter amplifiers 35 ₁ and 35 ₂ , demodulator 3
6 ₁ , 36 ₂ and the level detectors 37 ₁ , 37 ₂ correspond to the demodulators 63 ₁ , 63 ₂ , output demodulated signals to the selector 64 and detected by the level detectors 37 ₁ , 37 ₂ . The reception levels RSSI1 and RSSI2 of each reception system are output to the level comparison unit 65.

Intermediate frequency band pass filter (IFBP
F) 38, transmission IF amplifier 39, mixer 40, transmission frequency band pass filter (RFBPF) 41, and transmission RF amplifier 42 correspond to the RF / IF transmission unit 68 and realize a function of converting a modulated signal into a radio frequency signal. To do.

The frequency synthesizer 43 and the hybrid (H) 44 correspond to the local oscillator 71.

[0027]

As described above, the TDMA-TDD is used.
In the diversity radio device of the present invention which adopts the system, the local oscillation signal is given to the transmitting means only when the signal is transmitted and the signal is transmitted from the antenna designated by the transmission diversity, and the signal output from the transmitting means to the antenna side is stopped when the signal is received. Can be made.

Therefore, it is possible to prevent the transmitted wave from sneaking into the receiving means side at the time of receiving the signal, and it is possible to perform excellent receiving diversity and transmitting diversity.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a transmission diversity control timing in the first embodiment.

FIG. 3 is a block diagram showing the configuration of a second embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a diversity wireless device corresponding to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a TDMA-TDD system.

FIG. 6 is a conventional TDMA-T that performs transmission / reception diversity.
It is a block diagram which shows the structure of a DD radio.

[Explanation of symbols]

 11 Hybrid (H) 12 Switch Control Section 13 High Frequency Switch (SW) 31 Reception Frequency Band Pass Filter (RFBPF) 32 Reception RF Amplifier 33 Mixer 34 Intermediate Frequency Band Pass Filter (IFBPF) 35 Limiter Amplifier 36 Demodulator 37 Level Detection Section 38 Intermediate frequency band pass filter (IFBPF) 39 Transmission IF amplifier 40 Mixer 41 Transmission frequency band pass filter (RFBPF) 42 Transmission RF amplifier 43 Frequency synthesizer 44 Hybrid (H) 61 Antenna 62 RF / IF reception unit 63 Demodulation unit 64 Selection unit 65 Level comparison unit 66 Burst generation unit 67 Modulation unit 68 IF / RF transmission unit 69 High frequency switch (SW) 70 Switch control unit 71 Local oscillator 72 High frequency switch (SW)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshiyuki Chiba 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. A plurality of antennas, a reception unit that performs reception diversity using the plurality of antennas, a transmission unit that performs transmission diversity using one antenna selected in the reception diversity, and A high-frequency switch means for connecting each antenna and the receiving means and for connecting the transmitting means and each antenna at the time of signal transmission is provided, and the frequency band of one carrier is time-divided and transmitted by a plurality of transmission / reception channels. And in a diversity radio device for receiving, the transmitting means is arranged between the local oscillator that outputs a local oscillation signal used for frequency conversion of a transmission signal and the transmitting means, and transmits the local oscillation signal only when transmitting a signal. A diversity radio device comprising switch means for inputting to the means.