JP2002185357A - Radio - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio for eliminating a drawback where two types of bandpass filters for the reception high frequency for a base station subsidiary communication system and for the direct communication system between mobile stations, and for reducing the number of reception high-frequency bandpass filter to one. SOLUTION: In the direct communication between mobile stations, a signal line is switched so that a frequency band (F2) passes through the corresponding bandpass filter 4 for high frequency after a reception signal passes through an antenna switch 1 and mode selection switches 6-1 and 3-1. A reception signal passing through the bandpass filter 4 is returned to a reception trunk via selection switches 3-2 and 6-2, is supplied to a reception section 11, and is demodulated by a baseband section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio, and more particularly, to a radio in a narrow band digital communication system.

[0002]

2. Description of the Related Art Conventionally, a narrow band digital communication system (SCP)
C / FDMA) standard (ARIBSTD-T61)
Defines two communication systems. This will be described with reference to FIG. The first communication method is a base station zone system in which one base station covers an operation area of a plurality of mobile stations in a form including a base station facility and a plurality of mobile station facilities. In this system, a base station is assigned radio carriers of an up / down pair, and a transmission wave of a mobile station is an up wave f2 and a transmission wave of a base station is a down wave f1. Communication is performed between the base station and the mobile station or between the mobile stations via the base station. This communication method is hereinafter referred to as a base station dependent communication method.

[0003] The second communication method is a communication method in which mobile stations directly communicate with each other using a radio carrier frequency f3 without passing through a base station, and is called a direct communication method between mobile stations. This direct communication method between mobile stations is used when mobile stations outside the area of the base station perform communication. The following 2
A conventional wireless device based on two communication methods will be described.

FIG. 2 is a block diagram showing an example of a configuration of a wireless mobile station compatible with a narrowband digital communication system. Assuming that the downlink reception radio frequency band is F1 and the uplink transmission radio frequency band is F2, among the radio carriers of the uplink and downlink pair, the downlink reception radio carrier is f1 (f1 is one wave in the F1 band), and the uplink transmission radio carrier is (F2 is one wave in the band of F2), and the wireless carrier for transmission / reception used in the direct communication method between mobile stations is f3.

[0005] The transmission system transmits the modulated signal from the baseband section 12 to the P
It is configured to be amplified by A2. The receiving system is
A base station dependent communication line is connected to the terminal b of the communication mode changeover switches 6-1 and 6-2, and the band-pass filter 7 corresponds to the frequency band F1. A direct communication line between mobile stations is connected to the terminal a of the communication mode changeover switches 6-1 and 6-2, and the band-pass filter 15 corresponds to the frequency band F2. Further, the received signal passes through an amplifying unit 8, a frequency converter 9 for frequency-converting a local signal from a local oscillator 10, and a receiving 1F (intermediate frequency) unit 11 for limiting and amplifying a signal band, and then a baseband unit At 12, demodulation processing is performed. Switching between transmission and reception is performed by the antenna switch 1.

In this conventional radio mobile station, the radio carrier frequency f3 for direct communication between mobile stations is determined to be one wave within the transmission frequency band (uplink band) F2 or very close to F2. In the transmission high-frequency section, the radio frequency band-pass filter 4 can be covered by one filter that covers the band of F2. However,
Since the reception frequency band (downstream band) F1 is far from f3, the reception high-frequency section includes the radio frequency bandpass filter 7 covering the F1 band and the radio frequency bandpass filter 15 covering f3. It is necessary to install two. These two bandpass filters 7 and 15
Is performed by sending a control signal from the baseband unit 12 to the changeover switches 6-1 and 6-2 according to the received frequency.

[0007] The received signal passes through a band-pass filter corresponding to the frequency, is amplified by an amplifier 8, is mixed with a local signal generated by a local oscillator 10 by a frequency converter 9, and is input to a reception 1F section 11. Is done. The reception 1F unit 11 performs band limitation by a filter and amplification by an amplifier, and supplies an intermediate frequency signal to the baseband unit 12. In the baseband unit 12, the received signal is demodulated by a required demodulation method.

[0008]

In the above-described conventional mobile station radio, the first image spurious and the first. A high-frequency band-pass filter for reducing IF / 2 spurious is required. Specifically, the reception high-frequency unit of the wireless device includes a reception high-frequency band-pass filter 7 of the base station dependent communication system and a reception high-frequency band-pass filter 15 of the direct communication method between mobile stations.
There is a disadvantage that two types of bandpass filters for high frequency reception are required. SUMMARY OF THE INVENTION It is an object of the present invention to provide a wireless device in which two types of bandpass filters for reception high frequency, which were conventionally required in a reception high frequency unit, are reduced to one type.

[0009]

According to the present invention, in order to achieve the above object, an antenna, an antenna switch connected to the antenna for switching between a transmission signal and a reception signal, and a pass band corresponding to a transmission frequency band F2 are provided. , A second high-frequency band-pass filter having a pass band corresponding to the reception frequency band F1, a transmission unit, and a reception unit, and the reception signal is the first signal. Switching means for switching a signal line so as to pass through one of the high-frequency band-pass filter and the second high-frequency band-pass filter; and a direct communication mode between mobile stations (that is, within the transmission frequency band F2 or During the period when a signal in a frequency band very close to F2 is received), the received signal passes through the first high-frequency band-pass filter and is then supplied to the receiving unit. Those comprising automatically switching control allowed to control means a signal line so that.

[0010] Further, the control means, when in the base station dependent communication mode (ie, during a period of receiving a signal in the reception frequency band F1), the reception signal passes through the second high-frequency band-pass filter. Then, the signal lines are automatically switched to be supplied to the receiving unit. For example, the control unit is provided in the baseband unit, and switches the signal line automatically by supplying a switching control signal to each switching unit in accordance with the two types of communication modes described above.

[0011]

An embodiment according to the present invention will be described with reference to FIG. However, the frequencies F1, F2, f1,
The relationship between f2 and f3 is the same as that of the above-described conventional technology. To illustrate the frequency, the band F1 = 383.9 MH
z-386.2 MHz, band F2 = 365.9 MHz-
368.2 MHz, where f1 is one frequency in the band F1 and f2 is one frequency in the band F2. F3 is, for example, 365.9 MHz (one frequency in the band F2).

As shown in FIG. 1, the transmission system amplifies the modulated signal from the baseband unit 12 by the PA 2 via the transmission unit 5 and the band-pass filter 4. At this time,
Changeover switches 3-1 and 3 for switching transmission and reception lines
-2 is connected to the d terminal. In the receiving system, a base station dependent communication line is connected to the terminal b of the communication mode changeover switches 6-1 and 6-2, and the bandpass filter 7 corresponds to the frequency band F1. A direct communication line between mobile stations is connected to the terminal a of the communication mode changeover switches 6-1 and 6-2, and the band-pass filter 4 corresponds to the frequency band F2. Further, the received signal includes an amplifying unit 8, a frequency converter 9 for frequency-converting a local signal from a local oscillator 10, and a reception IF for limiting and amplifying a signal band.
Via the (intermediate frequency) unit 11, the baseband unit 12
Is demodulated. Switching between transmission and reception is performed by the antenna switch 1.

In FIG. 1, the radio frequency signal received from the antenna corresponds to whether the communication system is a base station dependent communication system or a direct communication system between mobile stations.
The reception signal line is switched using the changeover switch 6. For example, in the case of the base station dependent communication system, the route 13 is selected. On the other hand, in the case of the direct communication system between mobile stations, it is configured so that the signal further passes through one changeover switch 3-1, passes through the bandpass filter 4, passes through the changeover switch 3-2, and returns to the main line of the received signal. I have.

The changeover switches 6-1 and 6-2 are used to switch between a base station dependent communication mode and a direct communication mode between mobile stations.
Use MIC or the like. Also, changeover switches 3-1 and 3
-2 is a switch for switching the transmission line between the transmission line and the reception line, and the GaAs switch MMI
Use C or the like. In both the base station dependent communication method and the direct communication method between mobile stations, after passing through the mode changeover switch 6-2 after the high-frequency band-pass filter, the same path as in the related art is followed. The received signal band-limited by the high-frequency band-pass filter is amplified by the amplifier 8, mixed with the local signal generated by the local oscillator 10 by the frequency converter 9, and input to the IF unit 11. In the IF unit 11, band limitation by a filter and amplification by an amplifier are performed, and an intermediate frequency signal having a fixed level is supplied to the baseband unit 12. In the baseband unit 12, the received signal is demodulated by a required demodulation method.

[0015]

As described above, according to the present invention, a reception high-frequency band of a base station subordinate communication system and a reception high-frequency band of a direct communication system between mobile stations are conventionally used in a reception high-frequency section of a radio. Although two types of pass filters were required, the configuration is such that a transmission high-frequency band-pass filter and a reception high-frequency band-pass filter for direct communication between mobile stations are used together, so that the cost of one expensive reception high-frequency filter is increased. And the mounting area can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating a configuration example of a conventional wireless device.

FIG. 3 is a diagram illustrating a configuration and a communication system of a communication system.

[Explanation of symbols]

1: antenna switch, 2: PA, 3: transmission / reception line switch, 4: transmission high-frequency band-pass filter,
5: transmission high frequency unit, 6: mode changeover switch, 7: reception high frequency bandpass filter, 8: amplifier, 9: frequency converter, 10: local oscillator, 11: reception 1F unit, 1
2: baseband section, 13: base station dependent communication line, 1
4: Direct communication line between mobile stations, 15: Bandpass filter for reception high frequency.

Claims (2)

[Claims] An antenna, an antenna switch connected to the antenna for switching between a transmission signal and a reception signal, a first high-frequency band-pass filter having a pass band corresponding to a transmission frequency band F2, and a reception frequency band F1 A wireless device including a second high-frequency band-pass filter having a pass band corresponding to the following, a transmitting unit, and a receiving unit, wherein a received signal is one of the first and second high-frequency band-pass filters. A switching unit for switching a signal line so as to pass through one side, and when receiving a signal in a frequency band within or close to the transmission frequency band F2, the received signal is converted to the first signal.
And control means for switching the signal line so as to pass through the high-frequency band-pass filter. 2. The wireless device according to claim 1, wherein said control means, when receiving a signal in said reception frequency band F1, causes a signal line to pass through a second high-frequency band-pass filter. Characterized in that the wireless device is a control means for switching control of the wireless device.