JP3208343B2 - Diversity device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a base station of a mobile communication system such as a personal handy phone system (hereinafter abbreviated as "PHS") for performing wireless communication with a mobile station in a service area by a diversity system. The present invention relates to a diversity device to be used.

[0002]

2. Description of the Related Art In recent years, communication services for wirelessly communicating between a plurality of mobile stations and a base station have become widespread. Today, together with communication with a base station in a smaller zone, a parent service provided in a home has been developed. A PHS capable of providing a communication service capable of communicating with a device has been put to practical use.

[0003] In such a PHS, the transmission output of the base station side device is reduced to reduce the size and cost of the base station side device. By reducing the transmission output of the base station-side device, the service area of each base station is reduced, and accordingly, a large number of base stations are installed such that the mutual installation interval is reduced.

FIG. 2 shows a TDMA (Time Divis) for communication between a base station CS and a mobile station PS of a conventional PHS.
ion Multiple Access) / TDD (Time Division Duple)
x) It is explanatory drawing which shows an example of a frame. In FIG. 2, “#” indicates an individual time slot, “T” indicates transmission, and “R” indicates reception. According to the PHS standard (RCR STD-28), each TDD frame is set to 5 msec, and each time slot is set to 625 μsec.

In this PHS, each TDD shown in FIG.
# 1 (time slot 1) of a frame is used as a control physical slot, and # 2 (time slot 2), #
3 (time slot 3) and # 4 (time slot 4) are used as communication physical slots.

Each base station CS uses the control channel # 1 (ie, # 1T and # 1R) once every 100 msec to register the location of the mobile station PS located within its own service area, and Communication for setting a communication channel to the mobile station PS is performed. Each base station CS
The mobile station PS performs communication on the control channel # 1, for example, at the carrier frequency of the carrier number 71 (1916.150 MHz) defined in the PHS standard.

In the above-described communication channel setting process, the base station CS allocates one empty slot of the communication channels (# 2 to # 4) to the corresponding mobile station PS. Then, to the mobile station PS, one of the carrier frequencies to be used for making a call in the assigned slot is assigned from the available carriers for outdoor public communication carriers defined in the PHS standard. The mobile station PS
Moves to the assigned speech channel and speaks in the assigned slot and frequency.

[0008] When communication between the base station CS and the mobile station PS is performed by wireless communication as in the PHS, the base station CS and the mobile station PS are subject to fading or the like.
It is an unavoidable problem that the call state between the user and the server deteriorates.

[0009] This fading occurs, for example, in the base station CS.
It is caused by the interference between the reflected wave or the diffracted wave when the radio wave transmitted from the mobile station is reflected by the building and reaches the mobile station, and the radio wave directly reaching the mobile station PS from the base station CS. .

Actually, the wavelength of the radio wave used for the PHS is about 20 cm, so that if the difference in propagation distance between a plurality of radio waves is an integral multiple of this wavelength, the sum will be even larger. However, if the difference is shifted by a half cycle, the difference is canceled out, and the radio wave is significantly reduced.

[0011] For this reason, in order to keep the communication between the base station and the mobile station in a stable communication state, for example, a communication system based on diversity such as reception diversity or transmission diversity has been used.

[0012] Diversity has a small correlation with each other.
That is, the effect of fading is reduced by preparing two or more systems with a low probability that the line quality will be degraded at the same time and selecting or combining their outputs.

[0013] Among them, reception diversity includes, for example, reception of communication by a plurality of antennas installed at predetermined intervals or more, and among the antennas, the reception content by the antenna that has generated the highest reception signal level. ,
There is a method of selectively demodulating and using the reception result.

[0014] In the transmission diversity, for example, communication is received by a plurality of antennas installed at predetermined intervals or more, and transmission is performed by the antenna that has generated the largest received signal level among the antennas. There are methods.

Conventionally, diversity has been to select and use an antenna having good reception sensitivity (highest reception signal level) from a plurality of antennas. Unless a lossy combiner is used, a plurality of antennas using diversity are used. However, there is only one transmission / reception system. However, since the PHS has only three communication lines in one system, the communication traffic volume is high where there are many users of the mobile station such as in an urban area. Therefore, it is desirable to increase the number of base stations that can be connected simultaneously. However, it was difficult because of the expense for securing the installation location of the base station.

Therefore, as described below, it has been considered to increase the number of communication lines in one base station.

FIG. 3 is a block diagram showing a configuration of a part of a base station comprising a diversity device used for transmission in a conventional example.

Reference numerals 501 to 504 denote antennas for transmitting and receiving wirelessly, reference numerals 511 to 514 denote transmission / reception changeover switches which are switched according to a transmission section and a reception section, and reference numerals 521 to 524 tune to two systems of received signals and adjust the frequency up to the IF signal band. The receiving unit 531, which converts and measures the received signal levels of the two systems to output the RSSI signal, has a receiving unit 521
To 524, the antennas 501 to 504 having the maximum reception level in each system are determined,
A determination unit that outputs a determination signal, 532 is a selection unit that controls the antenna changeover switches 551 to 552 so as to select an antenna to transmit based on the determination signal, and 541 to 542 are HPAs that amplify the power to transmit the signal. 56
Reference numeral 4 denotes a synthesizer for synthesizing signals of two systems.

A specific description will be given. The receiving units 521 to 524 have the same configuration, and extract two systems of modulated signals having the carrier frequency assigned to the time slot from the received signals received by the corresponding antennas 501 to 504, respectively.

The receiving units 521 to 524
Outputs an RSSI signal by measuring the received signal level of the extracted modulated signal.

Next, the determination section 531 and the selection section 532 will be described. These sections are usually configured to be realized by a microcomputer or the like executing a program.

The determination unit 531 determines whether the reception unit 521 to the reception unit 52
4, the largest received signal level is obtained from the RSSI signals, and the antenna that has obtained the highest level is determined and output to the selection unit 532. These operations are the first
This is performed for each of the system and the second system.

In each of the downlink time slots of the TDD frame, the selecting section 532 further selects, from the two antennas determined by the determining section 531 in the corresponding immediately preceding uplink time slot, the maximum reception rate determined by the determining section 531. Corresponding to the antenna with the higher signal level,
In order to select one of the synthesizers 561 to 564,
Antenna switch 551 and antenna switch 5
52, and outputs a select signal.

The HPA 541 is a modulation signal to be transmitted to the mobile station PS assigned to each time slot of the first TDD frame (that is, a first-system modulation signal).
Is amplified and output to the antenna changeover switch 551.

The HPA 542, like the HPA 541,
A modulated signal to be transmitted to the mobile station PS assigned to each time slot of the second TDD frame (that is, a modulated signal of the second system) is amplified and output to the antenna switch 552.

The antenna switch 551 is connected to the selector 5
32, the synthesizers 561 to 5
One of the four output terminals connected to each of the 64 output terminals
One of them is selected, and the amplified output signal of the first system is output from the selected output terminal.

Similarly, the antenna changeover switch 552 is
According to the selection signal from the selection unit 532, the synthesizers 561 to 561
One of the four output terminals connected to each of the combiners 564 is selected, and the amplified output signal of the second system, which is the input, is output from the selected output terminal.

Thus, the antenna changeover switch 551
And the antenna changeover switch 552, the selection unit 53
The output terminals connected to the same combiner are selected according to the selection signal from the two.

Each of the combiners 561 to 564 has the same configuration, and outputs the first
When a modulation signal of the system and a modulation signal of the system 2 are input, the two inputs are mixed and output to the corresponding transmission / reception changeover switches 511 to 514.

The mobile station PS corresponding to the base station 500
During the standby state, for example, the carrier number 71
(1916.150 MHz) carrier frequency and TDD
The base station 500 communicates with the base station 500 using the control channel allocated to frame # 1, and performs its own location registration and the like. Further, after the base station 500 allocates the communication channel and the carrier frequency, the base station 500 sets its own reception frequency and transmission frequency to the allocated frequency, and performs communication using the allocated communication channel.

According to these configurations, one base station 500 can simultaneously communicate with up to seven mobile stations PS in the service area, and can perform reception diversity and transmission using four antennas. By performing diversity, communication with the mobile station PS can be performed with high accuracy. The base station 500 is connected to the mobile station PS.
Since the communication can be performed without adding a new component to the above configuration, the existing mobile station PS can be used in the PHS.

Next, the relationship between the system and the slot in the conventional example will be described with reference to FIG. For example, assume that the first slot of the first system and the second slot of the second system are simultaneously communicating. Uplink (communication from PHS terminal to PHS base station)
In the section, each of the receiving units 521 to 524 performs reception, measures a reception level, and outputs an RSSI signal.

As described above, the determination unit 531 determines which of the antennas 501 to 504 has the highest reception level from the RSSI signals from the reception units 521 to 524.

The receiver having the best reception level is determined to be the first antenna 501 in the first system and the fourth antenna 504 in the second system from the signals RX1 and RX5 in FIG. Output to The selection unit 532 sets the antenna changeover switch 551 to the first position in the down section (communication from the PHS base station to the PHS terminal) in response to the determination (selection) signal.
The antenna 501 and the antenna changeover switch 552 perform control so that the antenna 504 is selected.

At this time, even if the same antenna is selected, the two transmission signals are combined by the combiners 561 to 564 and transmitted from one antenna. That is, the transmission signal is amplified by the HPA 541 or HPA 542, and the antenna changeover switch 551 to the antenna changeover switch 554 is selectively used. The data is transmitted via a path 504.

[0036]

However, in the prior art, there is a problem that a power loss of about 5 dB including the combiner occurs through a combiner, which is a circuit having a large power loss, before transmission.

That is, before transmission, if the power loss is large, it is necessary to increase the output of the HPA. However, if the HPA output is large, the amplifying element (FET, etc.) which is the center of the actual circuit becomes expensive. This leads to an increase in base station manufacturing costs.

Further, since the output power is large, the power consumption is also large, and there is a problem that the cost for maintaining the base station such as the electricity bill is increased.

Further, there is a problem that the configuration of the radio system (high-frequency circuit portion) is complicated, difficult to design, and difficult to manufacture.

Accordingly, an object of the invention is to solve the above problems.

[0041]

SUMMARY OF THE INVENTION The present invention relates to a diversity apparatus using a TDMA system in which a plurality of communication channels including a control channel are set in respective time-divided slots and communication is performed by diversity. A system unit including at least two of a first transmission / reception system and a second transmission / reception system capable of performing communication at a timing, each system unit includes a plurality of transmission / reception antennas for transmission / reception, and the plurality of transmission / reception antennas. An antenna switching means connected by a control signal to output a transmission output from one of the transmission / reception antennas; a transmission means connected to the antenna switching means for generating a transmission signal; and Demodulating the signals received from the plurality of transmitting / receiving antennas into IF signals, detecting the received electric field level, and outputting the signals. A plurality of receiving means, and a modulation / demodulation means connected to the transmission means and the reception means for modulating a signal to the transmission means and demodulating a signal from the reception means, and arranged at a stage preceding the transmission means. A system switching unit that can replace each signal line of each system unit with a control signal, and according to the detected reception electric field level, determine the transmission / reception antenna to transmit the transmission signal of each system, Determining means for outputting a result, and control means for outputting the control signal so that signals transmitted by the respective systems can be transmitted by different transmitting / receiving antennas from the output of the determining means. To provide a diversity device.

[0042]

FIG. 1 is a block diagram showing a partial configuration of a PHS base station 100 according to a first embodiment of the present invention.

The base station 100 includes antennas 101, 102, 103, and 104 that perform transmission and reception by radio, and a transmission and reception switch 111 that switches between transmission and reception sections.
112, 113, 114, and band-limiting filters 105, 10 for passing only signals in the communication band from the received signals.
6, 107, 108 and transmission antenna changeover switches 109, 110 for switching the antenna for transmission.
And low-noise amplifiers 115, 116, 117, and 118 with little deterioration in C / N ratio (carrier-to-noise ratio: ratio of received signal power to receiver noise temperature), and isolators 119 and 120 that pass transmission signals in only one direction. And a distributor 12 for distributing signals received from each antenna into two systems.
1, 122, 123, and 124, low-pass filters 125 and 126 for suppressing high-frequency spurs, which are unnecessary waves generated during processing, in addition to carrier waves used for communication, and a power amplifier for amplifying to a power level at which a signal is transmitted. (Also referred to as HPA).

The base station 100 further includes receiving sections 131 and 132 in which processing sections for processing the received signal and outputting the IF signal and the RSSI signal are individually connected to the distributors 121, 122, 123 and 124, respectively. Transmitters 133 and 134 that perform processing to become a signal in a frequency band for transmitting a modulated signal, or that perform modulation by a baseband signal and perform processing to convert a signal in a frequency band to be transmitted to a modulated signal, and these receivers 131 , 132 and PLL synthesizers 135 and 136 for supplying a local frequency to a radio circuit including the transmitters 133 and 134, and a PLL for controlling at which frequency a signal generated by the PLL synthesizer is transmitted.
It also has a configuration of the control units 137 and 138.

Further, base station 100 has D / A processing sections 141 and 142 for converting digital signals into analog signals.
A / D processing units 143 and 144 for converting an analog signal to a digital signal, and RSSI signals converted to digital signals from receiving units 131 and 132 are input, and a determination is made to determine a priority for selecting an antenna based on the RSSI signal. Part 145
And a control unit 146 that controls the antenna changeover switches 109 and 110 and the cross switch 160 based on a signal from the determination unit 145 and controls transmission of a transmission signal from a better antenna.

Further, base station 100 uses the signal from control section 146 to transmit the signal from the determined antenna.
A cross switch 160 for exchanging data of two systems of a first system and a second system, and a modulation / demodulation processing unit 151, 1 for generating a modulated signal or a baseband signal and demodulating a received signal.
52, and TDMA processing units 171 and 172 that transmit data in synchronization with the slot of the frame and output the received signal for each slot.

An embodiment of the present invention will be described with reference to an example of a list of ranks according to reception levels shown in FIG.

As a first example, for example, the first system
It is assumed that the slot and the first slot of the second system are used for communication. In the up section, each of the receiving units 131 and 132 receives a signal, measures a reception level, and outputs an RSSI signal.

First, the determination unit 145 includes the reception units 131 and 13
It is determined which antenna has the highest reception level from the RSSI signal from the second antenna. Therefore, the reception level is shown in FIG.
According to the example shown in FIG. 14, the determination unit 14 determines that the antenna 101 is higher in the first system and the antenna 104 is higher in the second system.
5, and outputs a determination signal to the control unit 146.

Based on the determination signal, the control unit 146 having received the signal determines whether the cross switch 160 is in the down section, the first system is on the antenna 101 and 102 side, and the second system is the antenna 1
Control is performed such that the transmission antenna changeover switch 109 selects the antenna 101 and the transmission antenna changeover switch 110 selects the antenna 104.

Therefore, the transmission signal of the first system passes through the cross switch 160 without crossing, and is transmitted from the antenna 101 selected by the transmission antenna switch 109.

The transmission signal of the second system also passes through the cross switch 160 without crossing, and is transmitted from the antenna 104 selected by the transmission antenna switch 110.

Next, as a second example, it is assumed that the second slot of the first system and the second slot of the second system are simultaneously used for communication. This is indicated by RX2 and RX6 in FIG. As described above, each receiving unit 131,
132 performs reception, measures a reception level, and outputs an RSSI signal.

First, the determination unit 145 includes the reception units 131 and 13
It is determined which antenna has the highest reception level from the RSSI signal from the second antenna. Therefore, the reception level is shown in FIG.
According to the example shown in FIG. 14, the determination unit 14 determines that the antenna 101 is higher in the first system and higher in the second system.
5, and outputs a determination signal to the control unit 146.

However, with this configuration, it is not possible to output a transmission signal using the same antenna.

Therefore, the following processing is continuously performed to select a different antenna. First, among the reception levels received by the first system and the second system, the highest reception levels of both are compared, and the system having the lower received signal level is determined.

In the case of FIG. 4, in the antenna 101 having the highest reception level, the first system has a lower reception level than the second system, so that the lower first system is preferentially selected. That is, the antenna selected in the first system is the antenna 101. However, since the transmission antenna to be selected in the second system has not been determined, the determination is performed as follows.

Next, the determination section 145 attempts to determine an antenna to be transmitted in the undetermined second system. At this time, the reference is also the reception level in FIG. In the second system, the reception level from the antenna 102 is the second highest after the antenna 101 (third), so the antenna 102 is selected.

However, the first system is HPA127,
Since a system including the low-pass filter 125, the isolator 119, the transmission antenna switch 109, and the like is used, the system cannot be used.

Therefore, it is necessary to control to use a system including the remaining HPA 128, the low-pass filter 126, the isolator 120, the transmission antenna changeover switch 110, and the like.

Therefore, determination section 145 determines to transmit with antenna 3 (seventh) having the next highest reception level, and outputs a determination signal. Based on the determination signal, the control unit 146 controls the cross switch unit 160 to select the antenna 101 for the first system and the antenna 103 for the second system in the down section.

As a result, the transmission antenna changeover switch 1
09 selects the antenna 101, and the antenna changeover switch 110 selects the antenna 103.

As a third example, it is assumed that the third slot of the first system and the third slot of the second system are used for communication.

Each of the receiving units 131 and 132 receives the transmitted signal in the up section, measures the reception level,
Outputs the I signal. The determination unit 145 first receives the reception unit 131,
Based on the RSSI signal from 132, it is determined which antenna has the highest reception level.

Next, as a third example, it is assumed that the third slot of the first system and the third slot of the second system are simultaneously used for communication. This is indicated by RX3 and RX7 in FIG. As described above, each receiving unit 13 in the uplink section
1, 132 perform reception, measure the reception level, and
Outputs the I signal.

First, the determination unit 145 includes the reception units 131 and 13
It is determined which antenna has the highest reception level from the RSSI signal from the second antenna. Therefore, the reception level is shown in FIG.
According to the example shown in FIG. 14, the determination unit 14 determines that the antenna 101 is higher in the first system and higher in the second system.
5, and outputs a determination signal to the control unit 146.

However, as described above, according to this configuration, it is not possible to output a transmission signal using the same antenna.

Therefore, as in the second example, the following processing is continuously performed to select a different antenna. First, of the reception levels received by the first system and the second system, the reception levels with the highest reception levels are compared, and the system with the lower reception signal level is determined.

In the case of RX3 and RX7 in FIG. 4, in the antenna 101 having the highest reception level, the reception level of the second system is lower than that of the first system, so that the lower second system is given priority. Let me choose. That is, the antenna selected in the second system is the antenna 101. However, since the transmission antenna of the first system to be selected has not been determined, the determination is performed as follows.

Next, determination section 145 attempts to determine an antenna to be transmitted in the undetermined first system. At this time, the reference is also the reception level in FIG. In the first system, the reception level from the antenna 103 is the second highest after the antenna 101 (third), so the antenna 103 is selected.

Unlike the second example, since the same transmission system is not used for the antenna 103, the first system uses the antenna 103 and the second system uses the antenna 101 to perform transmission.

At this time, when transmitting the signal, the control unit 146 sets the cross switch 160 to the antenna 1
03. The second system controls so that transmission is possible via the antenna 101.

As described above, the systems are exchanged (the first system is the antennas 103 and 104, and the second system is the antenna 10).
1 and 102), the transmission unit 133,
The control unit 146 controls the PLL control units 137 and 138 so that the transmission frequencies of 134 are also adjusted to the respective transmission frequencies. Thereby, the frequency suitable for the channel can be transmitted.

That is, when a transmission signal from the first system is transmitted by the antennas 101 and 102, the PLL synthesizer unit 135 outputs a local frequency so as to have a frequency corresponding to each slot in the first system. However, when a transmission signal from the second system is transmitted by the antennas 101 and 102, the PLL synthesizer unit 135 outputs a local frequency so as to have a frequency corresponding to each slot in the second system. are doing.

Further, as a fourth example, the fourth system of the first system
It is assumed that the slot and the fourth slot of the second system are simultaneously used for communication. This is indicated by RX4 and RX8 in FIG. As described above, each receiving unit 13
1, 132 perform reception, measure the reception level, and
Outputs the I signal.

First, the determination unit 145 includes the receiving units 131 and 13
It is determined which antenna has the highest reception level from the RSSI signal from the second antenna. Therefore, the reception level is shown in FIG.
According to the example shown in FIG. 14, the determination unit 14 determines that the antenna 102 is higher in the first system and the antenna 101 is higher in the second system.
5, and outputs a determination signal to the control unit 146.

However, as described above, according to this configuration, it is not possible to output a transmission signal using the same antenna.

Therefore, the following processing is continuously performed in order to select a different route. First, among the reception levels received by the first system and the second system, the highest reception levels of both are compared, and the system having the lower received signal level is determined.

In the case of FIG. 4, in the antenna 102 having the highest reception level, the first system has a lower maximum reception level than the second system, so that the lower first system is preferentially selected. That is, the antenna selected in the first system is the antenna 102. However, since the transmission antenna to be selected in the second system has not been determined, the determination is performed as follows.

Next, determination section 145 attempts to determine an antenna to be transmitted in the undetermined second system. At this time, the reference is also the reception level in FIG. In the second system, the highest level received other than the path used is the level of the reception from the antenna 104 (fourth), so the antenna 104 is selected.

Therefore, determination section 145 determines to transmit with antenna 104 (fourth) having a high reception level,
Outputs a judgment signal. Based on the determination signal, the control unit 146 controls the cross switch unit 160 to select the antenna 101 for the first system and the antenna 103 for the second system in the down section.

As a result, the transmission antenna switch 1
09 selects the antenna 102, and the antenna changeover switch 110 selects the antenna 104.

Further, the flow of the operation will be described with reference to the flowchart of FIG.

In step 1, it is determined whether or not the slots used in the first system and the second system are the same, and if they are the same, the process proceeds to step 2; otherwise, the process is terminated. That is, if a plurality of systems use the same slot, transmission and reception must be performed at the same timing. This processing performed for that purpose is processing for determining the selected antenna.

In step 2, it is determined which antenna has the best reception level in each system from which antenna is receiving. If the first system, the process proceeds to step 3, and if the second system, the process proceeds to step 5. Move to.

In step 3, the one determined to be smaller in the comparison in step 2 is the step of determining the antenna used in the second system as the maximum reception level for the second system, and proceeds to step 4. .

In step 4, the second system is used for the first system.
The antenna having the next higher reception level is selected from the remaining antennas other than those used by the system, and the process proceeds to step 7.

In step 5, the one determined to be smaller in the comparison in step 2 is the step of determining the antenna used in the first system having the maximum reception level as the first antenna, and proceeds to step 6. I do.

In step 6, the second system
The antenna having the next higher reception level is selected from the remaining antennas other than those used by the system, and the process proceeds to step S8.

At step 7, it is determined whether the selected antenna (step 4) and the determined antenna (step 3) pass through the same route.
If they are the same, the process returns to step 4, and if they are different, the process proceeds to step 9.

In step 8, it is determined whether the selected antenna (process in step 6) and the determined antenna (process in step 5) do not pass through the same route.
If they are the same, the process returns to step 6, and if they are different, the process proceeds to step 9.

Step 9 is a step of deciding an antenna to be used in one of the undecided systems and controlling to transmit using the decided antenna.

According to this flowchart, the first
Examples 4 to 4 can be realized.

As another embodiment, a circuit block shown in FIG. 6 can be considered. This is different from FIG.
2 and the cross switch unit 160 are interchanged, and similar effects can be obtained.

That is, the cross switch section 160 switches the path, and may be arranged at any position as in the circuit block of FIG. 1 or FIG.

Further, the cross switch section 160 is not limited to being arranged at these places, but may be arranged at any place as long as the path is to be switched, and by controlling according to the arrangement place, Similar effects can be obtained.

[0097]

According to the present invention, one system does not select and use a plurality of antennas by using a combiner as in the prior art, and uses only a plurality of antennas determined for each system. All the antennas can be selected in each system without any delay. Therefore, the quality of the wireless channel is stabilized (improved) without increasing the cost. In addition, since the antenna selection is assigned not only to the radio circuit but also to the digital circuit, the radio circuit is simplified,
It is easier to manufacture.

Further, when an attempt is made to obtain an equivalent diversity effect without using a synthesizer as in the prior art (the number of systems × 1).
Since a plurality of systems can transmit and receive with a common antenna as compared with (the diversity number of antennas = the number of antennas is large), the cost can be reduced. That is, miniaturization is facilitated, and, for example, when used for a PHS base station, installation and transportation of the base station are facilitated.

Further, since the output of the HPA can be low,
Power consumption is reduced.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing an example of a TDMA / TDD frame for performing communication between a PHS base station CS and a mobile station PS.

FIG. 3 is a block diagram showing a conventional diversity device.

FIG. 4 is an explanatory diagram showing an example of a TDMA / TDD frame explaining the present invention.

FIG. 5 is a flowchart illustrating an embodiment of the present invention.

FIG. 6 is a circuit block diagram of the diversity device according to the first embodiment of the present invention.

[Explanation of symbols]

 100, 101 'Base stations 101-104 Transmission / reception antennas 105-108 Band limiting filters 109, 110 Transmission antenna changeover switches 111-114 Transmission / reception changeover switches 115-118 Low noise amplifiers 119, 120 Isolators 121-124 Dividers 125, 126 Low band Pass filters 127, 128 Power amplifiers (HPAs) 131, 132 Receivers 133, 134 Transmitters 135, 136 PLL synthesizers 137, 138 PLL controllers 141, 142 D / A processors 143, 144 A / D processors 145 Judgment Unit 146 Control unit 151, 152 Modulation / demodulation processing unit 160 Cross switch 171, 172 TDMA processing unit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-209932 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 7/00 H04B 7/02-7 / 12 H04L 1/02-1/04

Claims (2)

(57) [Claims] 1. A diversity device using a TDMA system in which a plurality of communication channels including a control channel are set in respective time-divided slots and communication is performed by diversity, and communication can be performed at substantially the same timing. A system unit including at least two of a first transmission / reception system and a second transmission / reception system; each system unit includes a plurality of transmission / reception antennas for performing transmission / reception; Antenna switching means switched by a control signal to output from the transmitting and receiving antennas; transmitting means connected to the antenna switching means to generate a transmission signal; connected to the plurality of transmitting and receiving antennas and receiving from the plurality of transmitting and receiving antennas A plurality of receiving means for demodulating the respective signals into IF signals, detecting the received electric field level, and outputting the received electric field levels; A modulating / demodulating means connected to the transmitting means and the receiving means, modulating a signal to the transmitting means, and demodulating a signal from the receiving means. System switching means capable of switching each signal line by a control signal; determining the transmitting and receiving antennas to transmit the transmission signal of each of the system units according to the detected reception electric field level; and determining the result. And a control unit that outputs the control signal so that signals transmitted by the respective system units can be transmitted by different transmission / reception antennas based on an output of the determination unit. 2. The transmission / reception antenna according to claim 2, wherein the transmission / reception antenna determined to select a certain system is determined to be the same as the transmission / reception antenna selected and determined by another system. 2. The diversity apparatus according to claim 1, wherein the transmission / reception antenna is allocated to a system having a smaller reception level of the system from which the antenna is selected, and the other system is allocated to select the remaining transmission / reception antenna. .