JPH09181663A - Diversity communication method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the scale of mobile station configuration of the diversity system small. SOLUTION: A base station 3 sends means information from a transmitter 31 from either of antennas 13, 14 in one frame and a base station antenna changeover switch 32 is switched by a transmission controller 33 to send a branch quality detection signal from the other antenna in the same frame. A mobile station 4 uses a detector 25 to detect the communication information and a reception level at the reception of the branch quality detection signal and provides an output of a branch quality communication signal (b) representing which is larger. A transmitter 41 sends the maintenance information to the base station and the signal (b) in one frame to the base station and the transmission controller 33 of the base station checks the signal (b) to decide a transmission antenna for a succeeding frame and controls the switch 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity communication method and apparatus, and more particularly to frequency division multiplexing (FD).
D: Diversity communication method suitable for a terrestrial digital mobile communication system using a Frequency Division Duplex and a device therefor.

[0002]

2. Description of the Related Art In a mobile communication system, a radio wave propagation path is often complicated by reflection of a building, and moreover, the electric field level of the received electric field fluctuates by changing momentarily. For this purpose, a diversity method is used in which a plurality of antennas are provided and switched for use.

FIG. 3 is a block diagram showing a configuration example of the base station 1 and the mobile station 2 using the above-mentioned diversity method. Two antennas 13 and 14 are installed in the base station 1, two antennas 23 and 24 are installed in the mobile station 2, and two propagation paths F1-of frequency F1 are used as downlinks.
C and F1-D, and two propagation paths F2-A and F2-B having the frequency F2 are formed as the uplink.

In the above configuration, first, in the downlink, a transmission signal from the transmitter 11 of the base station 1 having a transmission frequency of F1 passes through the base station duplexer 12 and the base station antenna 13
Sent from. The radio waves transmitted from this base station are respectively received by the mobile station antenna 23 through the propagation path F1-C and the mobile station antenna 24 through the propagation path F1-D, and are diversity-combined. That is, the mobile station antenna 2
The signal received at 3 passes through the mobile station duplexer 22 at the mobile station detector 25, the signal received at the mobile station antenna 24 is detected at the mobile station detector 26, and each detected signal is a mobile station demodulator. It is demodulated at 27.

Next, in the uplink, the transmission signal from the mobile station transmitter 21 whose transmission frequency is F2 is transmitted by the mobile station duplexer 2
The signal is transmitted from the mobile station antenna 23 through the line 2. The radio waves transmitted from this mobile station are received by the base station antenna 13 via the propagation path F2-A and the base station antenna 14 via the propagation path F2-B, and are diversity-combined. That is, the signal received by the base station antenna 13 passes through the base station duplexer 12 and is detected by the base station detector 15, and the signal received by the base station antenna 14 is detected by the base station detector 16. Are demodulated by the base station demodulator 17.

[0006]

As described above, it is known that high quality communication becomes possible by configuring the reception diversity in both the base station and the mobile station. However, in such a diversity communication system, the mobile station also has a receiving system
There is a drawback that the system becomes necessary and the circuit scale becomes large. This problem is disadvantageous for downsizing, low power consumption, and cost reduction of mobile stations.

An object of the present invention is to provide a diversity communication method and apparatus capable of reducing the size of a mobile station while maintaining high quality communication as in the prior art.

[0008]

According to the present invention, two antennas are installed in a base station and one antenna is installed in each mobile station, and the base station and any one mobile station are digitally operated. In a diversity communication method in which the base station switches to the antenna with the larger propagation path gain during communication, each downlink transmission frame from the base station to the mobile station is divided into two subframes, and one of One of the subframes which transmits the communication information to the mobile station to the mobile station via the antenna of the base station selected at the start of the frame, and which is different from the one selected by the other subframe. The mobile station that receives the transmission signal from the base station while transmitting the quality detection signal to the mobile station via the antenna of the base station The transmission frame of the line is divided into two subframes, and the communication information to the base station is transmitted by one of the subframes, and at the same time, the base station uses the two subframes to transmit through each antenna of the base station. The level of the received electric field of the received signal is checked to determine which is larger, the determination result is transmitted to the base station by the other subframe of the mobile station, and the base station that receives the determination result thus transmitted is received. Discloses a diversity communication method characterized in that an antenna to be selected for the next frame is determined based on the determination result.

Further, according to the present invention, the base station has a function of outputting downlink communication information and the following quality detection signal within one frame, two antennas, and each of the antennas transmitting and receiving. A duplexer installed for each antenna to enable shared use, a switch for switching to which of the two antennas the output from the transmitter is supplied, and the two The detection / demodulation means for detecting / demodulating the reception signal from the mobile station taken out through the duplexer received by the antenna, and the transmitter are different from the quality detection signal at the time of transmitting the communication information. The switch is switched so as to transmit from one of the antennas, and the mobile station is changed according to the content of the branch quality signal from the mobile station detected by the detector / demodulator. The mobile station further comprises a transmission control means for switching the switch at the start of the next frame so as to select an antenna having a higher reception electric field level, and the mobile station has one antenna and the transmission / reception of the antenna. A duplexer for enabling shared use, and detection and demodulation of the communication information and the quality detection signal transmitted from the base station from two antennas of the base station, and the communication information and the quality detection. Detecting which one of the electric field levels at the time of signal reception is large, and detecting and demodulating means for outputting the result as the branch quality signal,
Disclosed is a diversity communication device, comprising: a transmission means having a function of outputting uplink communication information and the branch quality signal within one frame.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to examples. FIG. 1 is a block diagram showing an example of a diversity communication device according to the present invention, and circuits having the same functions as those in FIG. 3 are assigned the same reference numerals. Although two antennas 13 and 14 are installed in the base station 3 of this communication device as in the conventional case, only one antenna 22 is installed in the mobile station 4, and the detector of FIG. 26 is also unnecessary. In the downlink, the propagation path F1-C from the antenna 13 to the antenna 23 and the propagation path F1-E from the antenna 14 to the antenna 23 in the downlink, and the propagation path F2- from the antenna 23 to the antenna 13 in the uplink. A and propagation path F2-B from antenna 23 to antenna 14
Is formed.

An example of the operation of the diversity communication device having the above configuration will be described with reference to the time chart of FIG. FIG. 2 shows the time change of the propagation gain in the propagation paths F1-C and F1-E of the downlink and the transmission / reception timing of transmission / reception data (digital data) and information for switching the propagation path. In the propagation path condition, the gain is improved in the + dB direction and the line quality is good, and the gain is decreased in the -dB direction and the line quality is poor. In the configuration example of FIG. 1, the clock signal line is not shown, and in the timing chart of FIG. 2, the propagation path delay of the transmission / reception time is omitted.

First, in the downlink, at the base station antenna selection timing t1, the base station antenna changeover switch 32 selects its contact s1 side by the base station antenna changeover signal a from the transmission controller 33 (selection). The method will be described later). When this selection is completed, the data BS-T1 from the base station transmitter 31 is transmitted at the reception frequency F1 from the base station duplexer 12 and the base station antenna 13, and the propagation path F
Received data MS at mobile station antenna 23 through 1-C
-Received as R1. Furthermore, at the base station antenna switching timing t2 in the middle of this frame, the base station antenna switching switch 32 selects the contact S2 side by the base station antenna switching signal a from the transmission controller 33.
From here until time t4 when the frame ends, the base station transmitter 31 outputs a branch quality detection signal Q1, which passes through the base station duplexer 35 and the base station antenna 1
Sent from 4. This signal is received as a reception signal CJ1 by the mobile station antenna 23 through the propagation path F1-E. The signal received by the mobile station antenna 23 passes through the mobile station duplexer 22, is detected by the mobile station detector 25, and is demodulated by the mobile station demodulator 42. In addition, the mobile station detector 25 receives an RSSI (Received Signal Streng
th Indicator) is detected. That is, the reception level of the data BS-T1 via the propagation path F1-C and the propagation path F1-
The reception level of the branch quality detection signal Q1 passing through E is detected, and a determination signal b representing these comparison determination results is sent to the transmitter 41.

Next, in the uplink, the uplink data MS-T1 is transmitted until the time t3 after the frame start timing t1. When the judgment signal b is input to the transmitter 41, the branch quality is changed. The notification signal AC1 is output from the transmitter 41. This is transmitted from the mobile station antenna 23 through the mobile station duplexer 22. The radio wave transmitted from this mobile station is transmitted to the base station antenna 13 through the propagation path F2-A and simultaneously to the base station antenna 14 through the propagation path F2-B. In the base station 3, the received signals BS-R1 and HE1 are detected by the base station detectors 15 and 16, and further, the respective detected signals are demodulated by the base station demodulator 34.

Of the demodulated signals, the demodulated signal c of the signal HE1 representing the branch quality is sent to the transmission controller 33, and the transmission controller 33 responds to this content by the base station antenna changeover switch 32 at the timing t4. Switch. This timing t4 is given by the frame end signal d sent from the transmitter 31. Hereinafter, the same operation is repeated for each frame. In the example of the propagation path situation shown in FIG. 2, in the frames from time t1 to t4, the gain of the propagation path F1-E gradually increases, so at time t4 (base station antenna selection timing), the base station antenna changeover switch. Three
2 is connected to the contact S2 side thereof, so that in the next base station transmission, the base station antenna 14 is passed through the base station duplexer 35.
Transmits data BS-T2. At this time, the radio wave transmitted from the base station passes through the propagation path F1-E and is received by the mobile station antenna 23. Then, at time t5 at the end of the frame, the base station antenna change-over signal a switches the base station antenna change-over switch 32 to its contact S1 side, and the branch quality detection signal Q2 is transmitted from the base station antenna 13 through the base station duplexer 12. To be done. The radio wave transmitted from this base station passes through the propagation path F1-C and is received by the mobile station antenna 23 as the signal CJ2. Since the signal received by the mobile station antenna 23 is demodulated in the same procedure as in the previous frame and the gain of each propagation path is detected by the mobile station detector 25, the propagation path F1-E is also high here. Since the gain is gain, the contact S2 side of the base station antenna changeover switch 32 is selected also at the next base station antenna selection timing t7. At the next base station antenna selection timing t10 after a further lapse of time, since the propagation path F1-C has a higher gain this time, the contact S1 side of the base station antenna changeover switch 32 is selected. In this way, a better propagation path is selected for each frame, and communication using a good propagation path is possible even if the mobile station is used as one antenna.

In the device configuration of FIG. 1, the base station antenna changeover switch 32, the transmission controller 33, the duplexer 35 and the like are added to the conventional configuration of FIG. 3, but all of these are equipment of the base station. However, since the circuits themselves are also simple and small, they do not become a factor that particularly complicates the system. Further, the branch quality detection signals Q1, Q2, ...
Alternatively, the transmission capacity of the original information is reduced due to the transmission of the branch quality notification signals AC1, AC2, ... However, the influence of these additional signals is extremely small because the number of bits is very small.

[0016]

As described above in detail, according to the present invention, the circuit scale of the mobile station can be reduced, and at the same time, the FDD can be reduced.
There is an effect that the diversity effect in the communication system can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a diversity communication device according to the present invention.

FIG. 2 is a timing chart showing an example of a downlink propagation path situation and an operation of the apparatus of FIG. 1 corresponding thereto.

FIG. 3 is a block diagram showing a configuration example of a conventional diversity communication device.

[Explanation of symbols]

 3 base station 4 mobile station 12, 35 base station duplexer 13, 14 base station antenna 15, 16 base station detector 22 mobile station duplexer 23 mobile station antenna 25 mobile station detector 31 base station transmitter 32 base station antenna switching Switch 33 Transmission controller 34 Base station demodulator 41 Mobile station transmitter 42 Mobile station demodulator

Claims (2)

[Claims] 1. A base station is provided with two antennas, and each mobile station is provided with one antenna, and a propagation path is provided on the base station side during digital communication between the base station and any one mobile station. In the diversity communication method in which the antenna with a larger gain is switched to, each of the downlink transmission frames from the base station to the mobile station is divided into two subframes, and one of the subframes transmits to the mobile station. The communication information is transmitted to the mobile station via the antenna of the base station selected at the start of the frame, and further via the antenna of the base station different from the one selected by the other subframe. The mobile station that has transmitted the quality detection signal to the mobile station and has received the transmission signal from the base station has two uplink transmission frames from the mobile station to the base station. It is divided into subframes, and one of the subframes transmits communication information to the base station, and at the same time, a reception electric field of a signal transmitted from each of the base stations via each antenna of the base station using two subframes. Of which is determined to determine which is larger, the determination result is transmitted to the base station by the other subframe of the mobile station, and the base station which receives the determination result thus transmitted,
A diversity communication method characterized in that an antenna to be selected for the next frame is determined based on the determination result. 2. A transmission means having a function of allowing a base station to output downlink communication information and a quality detection signal following it in one frame, two antennas, and each of the antennas is used for both transmission and reception. A duplexer installed for each of the antennas, a switch for switching to which of the two antennas the output from the transmitter is supplied, and reception by the two antennas. Detection / demodulation means for detecting / demodulating the received signal from the mobile station taken out via the duplexer, and the antenna of which the transmitter is different from that at the time of transmitting the communication information as the quality detection signal. The switch is switched to transmit from the mobile station, and the mobile station receives a higher level of reception depending on the content of the branch quality signal from the mobile station detected by the detection / demodulator. Transmission control means for switching the switch at the start of the next frame so that the antenna having the electric field level is selected, and the mobile station uses one antenna and the antenna for both transmission and reception. A duplexer for enabling detection and demodulation of the communication information and the quality detection signal transmitted from the base station from two antennas of the base station, and reception of the communication information and the quality detection signal. A detection / demodulation means for detecting which of the electric field levels at time is higher and outputting the result as the branch quality signal, and a function for outputting the uplink communication information and the branch quality signal in one frame. A diversity communication apparatus comprising: a transmission unit having the same.