JPH08331013A - Frequency hopping communication system - Google Patents

Abstract

PURPOSE: To simplify a radio base station installation by changing a conversion frequency of an up-converter of a base station converting a base band signal sent through a fixed channel from a central station into a radio signal according to a prescribed hopping pattern. CONSTITUTION: An exchange station inputs an information signal to a base band signal generating section 1 of a centralized station S, in which a base band signal is generated. The base band signal is sent to base stations B1-B3 via a fixed channel from a transmission section 3, an up-converter 5 converts the base band signal into a radio signal, and it is sent from a transmission section 11. Simple installation of the radio base station is enough by changing a converting frequency of the up-converter according to a hopping pattern.

Description

Detailed Description of the Invention

[0001]

The present invention is used in mobile radio communication systems. INDUSTRIAL APPLICABILITY The present invention is used in a mobile communication system using a frequency hopping communication system. The present invention is a system developed for a wireless communication system used in one large-scale facility such as an airport, but can also be used for other mobile communication systems. The present invention relates to a mobile wireless communication system suitable for individually selectively calling mobile wireless devices or performing simultaneous broadcast communication to mobile wireless devices.

The present invention was developed so that complex information can be transmitted with simple equipment with a small transmission power that does not require an individual radio station license.

[0003]

2. Description of the Related Art In wireless communication using digital signals, transmission or reception is performed in synchronization with a clock signal. For example, a frequency hopping communication method is known in which communication is performed while changing a carrier frequency used for communication according to a predetermined rule. Frequency hopping requires that transmission and reception be performed in synchronism, and the carrier frequency is changed every 20 mS with respect to a carrier frequency of, for example, over 1000, which is assigned in advance. Therefore,
Next, the transmitting / receiving device must hold the same hopping pattern as to which carrier frequency is to be used. This frequency hopping communication system is suitable for communication requiring confidentiality because it is impossible for a third party who does not know a predetermined hopping pattern to intercept the communication contents.

Frequency hopping communication was developed for military use, but in recent years it has become widely accepted for general use.
When the transmission power is below a certain level in the Hz band, wideband frequency allocation was performed without requiring a license to open an individual radio station.

Further, regarding the communication performed in the same frequency band, by setting different hopping patterns for each user, it is possible to effectively use the idle channel, so that the radio wave It can contribute to effective use. For example, in the case of a communication method in which N channels are assigned to N users, there are various restrictions on the use of that channel by other users, even if one of the users becomes dormant. . In such a case, the frequency hopping communication system allows the operating communication terminal to effectively utilize all of the N channels. Therefore, it is possible to allocate N channels to N or more users while considering the operating status.

An example of a communication system using such a frequency hopping communication system will be described with reference to FIG. FIG.
FIG. 1 is an overall configuration diagram of a communication system arranged in an airport. The radio base station B transmits a timing signal for synchronizing the clock signal of each mobile station C or fixed station F together with the information signal. The mobile station C or the fixed station F receives this timing signal and generates a clock signal substantially equal to the internal clock signal of the radio base station B. Then, frequency hopping is executed according to this clock signal.

[0007]

In a large-scale facility such as an airport, for example, a large number of airlines and a large number of companies utilizing the facilities are required to carry out mobile radio communication by assigning individual frequencies. In general, it is in a very difficult situation because there is no frequency margin. In the frequency hopping communication system as described above, the mobile radio communication system for each company can be set up without requiring a special radio station license when the transmission power is a small power below the regulation. However, the radio base station of the frequency hopping communication system has a drawback that the configuration is complicated and the base station equipment is expensive. In particular, in the frequency hopping communication system, in order to reduce interference and transmit not only voice information but also data or character information, which is compatible with multimedia, a large number of low-power radio base stations are arranged and a large number of radio base stations are arranged. It is advantageous to transmit synchronized transmission signals from the radio base stations of the above, in which case the base station equipment must be as inexpensive as possible.

The present invention has been made against such a background, and an object thereof is to provide a frequency hopping communication system capable of simplifying the equipment of a radio base station. It is an object of the present invention to provide a frequency hopping communication system suitable for arranging a large number of radio base stations that synchronously transmit low power transmission signals in one system. An object of the present invention is to provide a frequency hopping communication system suitable for transmitting call information, voice information, character information, and other composite information. An object of the present invention is to provide a frequency hopping communication system which can select a hopping frequency reasonably with less interference. SUMMARY OF THE INVENTION It is an object of the present invention to provide a frequency hopping communication system that is compatible with a conventionally used radio paging communication system.

[0009]

According to the present invention, a plurality of radio base stations transmitting a frequency hopping signal in which a carrier frequency changes according to a predetermined hopping pattern over time, and information on the hopping pattern are provided. A large number of mobile receivers that hold in advance and synchronously receive the frequency hopping signal transmitted by at least one of the radio base stations, and are connected to the radio base stations by a fixed line with the plurality of radio base stations. Frequency hopping communication system including a centralized station that controls the synchronization of the frequency hopping signals transmitted from the plurality of radio base stations while providing transmission information.

Here, a feature of the present invention is that the central station generates a signal to be transmitted simultaneously from the plurality of radio base stations as a baseband signal, and the baseband signal is fixed. Means for transmitting to a line, and the radio base station is provided with an up converter for converting a baseband signal coming from the fixed line into a frequency hopping signal that changes according to the hopping pattern.

As a result, the equipment of the radio base station can be simplified. INDUSTRIAL APPLICABILITY The present invention is suitable for arranging a large number of radio base stations that transmit low power transmission signals in synchronization in one system.

A transmission signal transmitted from the radio base station according to a baseband signal generated by the central station includes an identification code of the mobile receiver, and the mobile receiver is
Memory means in which the respective identification codes are individually set, comparison means for comparing the identification code set in the memory means with the identification code included in the transmission signal from the radio base station, and the coincidence output of the comparison means It is desirable to include a display means for displaying a call. This makes it suitable for transmitting call information.

The mobile receiver includes optical display means for displaying character information, and a transmission signal transmitted from the radio base station according to a baseband signal generated by the central station includes the character information. Can also be
This makes it suitable for transmitting character information.

A plurality of hopping patterns are set in the radio base station and the mobile receiver, and a plurality of hopping patterns are set in the base station signal transmitted to each radio base station via the fixed line to the central station. Of the hopping pattern, the radio base station comprises means for selecting the hopping pattern of the transmission signal according to the designated code, the mobile receiver from the radio base station It is also possible to adopt a configuration including means for selecting a hopping pattern of the reception frequency according to the designated code included in the received signal.

At least one of the radio base stations is monitored for spatial noise levels of a plurality of frequencies including a frequency to be next hopped during a period in which the transmission carrier frequency is one frequency according to the selected hopping pattern. A monitoring receiver and means for transmitting the monitoring result of the monitoring receiver to the central station via the fixed line are provided, and the central station sets a prescribed value for the frequency to be hopped next according to the monitoring result. When there is a noise level to be exceeded, there is provided a means for transmitting a code designating one of the hopping patterns into the baseband signal so that a frequency having a small noise level is included as a frequency to be hopped next. You can also As a result, there is little interference and the hopping frequency can be selected rationally.

At least one control channel is set in the baseband signal with a narrow frequency width, and the hopping pattern is set so that the hopping frequency is limited to a small number for all the hopping frequencies. , The central station is provided with means for transmitting a code designating one of the hopping patterns in the control channel, and the mobile receiver determines the frequency at which the control channel hops when newly activated. A configuration comprising control means for fixing one reception frequency and making it stand by, and performing hopping of the reception frequency according to the hopping pattern when a code designating one of the hopping patterns is detected on the control channel. You can also do it.

A second aspect of the present invention is a mobile receiver used in the frequency hopping communication system.

A third aspect of the present invention is to provide, in addition to the frequency hopping communication system, at least one fixed frequency type radio base station in which a fixed line is established between the centralized station and the fixed frequency. 2 is a wireless communication system characterized by comprising means for transmitting the baseband signal coming from the central station with a carrier of a fixed frequency.

As a result, it is possible to adapt to the conventional radio paging communication system.

[0020]

In the base station, the baseband signal transmitted from the central station via the fixed line is converted into the radio signal by using the up converter. At this time, the frequency hopping signal is generated by changing the conversion frequency of the up-converter according to the hopping pattern held in advance. By this means, it is possible to configure a radio base station that can be applied to the frequency hopping communication method using a simple configuration. Therefore, for example, it is suitable for use in a mobile radio communication system in which a large number of small base station devices are arranged.

The mobile receiver also holds the hopping pattern and can receive the frequency hopping signal from this radio base station. In the mobile receiver, the individual identification code of this receiver is stored in the memory, and when the identification code included in the transmission signal transmitted from the radio base station matches the identification code of its own, by displaying a call, For example, a wireless selective calling method can be realized.

Alternatively, the mobile receiver may be provided with optical display means for displaying character information, and the character information may be transmitted from the radio base station.

As for the hopping pattern which is held in advance, a plurality of hopping patterns are held so that one of the hopping patterns is included in the baseband signal from the central station. It is also possible to set a code for specifying one. further,
The code specifying any one of a plurality of hopping patterns included in this baseband signal is converted into a radio signal by the up converter and transmitted to the mobile receiver. The hopping pattern can be designated by a code designating any one of the above. As a result, the hopping pattern of the radio base station and the mobile receiver can be designated from a plurality of groups according to the designation of the central station and can be changed at any time. Therefore, by changing the hopping pattern, it is possible to deal with interference from the similar adjacent frequency hopping communication system and the like, and it is possible to improve confidentiality.

It is also possible to install a monitoring receiver for receiving in advance a plurality of frequencies to be hopping from the current position of the transmission carrier frequency and monitoring the spatial noise level of the frequencies. Then, the central station is notified of the monitoring result, and when the spatial noise level of the next hopping frequency is higher than the specified value and the spatial noise level of the next hopping frequency is below the specified value, then The central station may also send a code in the baseband signal that specifies a modification of a portion of the hopping pattern to skip the hopping scheduled frequency and hop to the next hopping scheduled frequency.

By this means, it is possible to avoid a situation in which a part of a series of information is lost, so that the signal error rate can be reduced and the signal retransmission time can be shortened.

At least one control channel with a narrow frequency width is set in the baseband signal of the central station, and when the mobile receiver is newly activated, it is sufficient to wait at any one of the hopping frequencies. Then, when the transmission signal including the control channel hops to that frequency, the mobile receiver extracts the code designating the hopping pattern currently in use from the control channel and sets its own reception frequency to the hopping pattern. Reception may be started by synchronizing.

By this, even if the mobile receiver does not know the hopping pattern currently being used in advance, the mobile receiver can perform reception by the frequency hopping communication system.

A fixed frequency type wireless base station may be provided together with such a frequency hopping communication type wireless base station. As a result, the information contained in the baseband signal from the central station can be received by the fixed frequency type mobile receiver.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of an embodiment of the present invention. FIG. 2 is a block diagram of a main part of the central station. FIG. 3 is a block diagram of a main part of the radio base station.

According to the present invention, a plurality of radio base stations B1 to B3 which transmit a frequency hopping signal whose carrier frequency changes according to a predetermined hopping pattern over time and information on the hopping pattern are held in advance. A plurality of mobile receivers M1 to M4 that synchronously receive the frequency hopping signal transmitted by at least one of the radio base stations B1 to B3, and a radio base station B1 connected to the radio base stations B1 to B3 by a fixed line. To B3, the frequency hopping communication system is provided with a central station S that gives transmission information to the wireless base stations B1 to B3 and controls synchronization of frequency hopping signals transmitted from the wireless base stations B1 to B3.

Here, a feature of the present invention is that the central station S has a baseband signal generator 1 as a means for generating signals to be transmitted all at once from the radio base stations B1 to B3 as a baseband signal. A transmission unit 3 as a means for transmitting the baseband signal to the fixed line,
The radio base stations B1 to B3 are provided with an up converter 5 for converting the baseband signal coming from the fixed line into a frequency hopping signal that changes according to the hopping pattern.

Next, the operation of the embodiment of the present invention will be described. FIG. 4 is a configuration diagram of a baseband signal or a transmission signal.
FIG. 5 is a block diagram of the main parts of the mobile receivers M1 to M4. The information signal is input to the baseband signal generation unit 1 of the central station S via the exchange connected to the network. The baseband signal generator 1 generates a baseband signal from this information signal. The baseband signal transmitted from the transmitter 3 of the central station S to the base stations B1 to B3 via the fixed line is converted into a radio signal by the upconverter 5 and transmitted from the transmitter 11. This transmission signal includes the identification codes of the mobile receivers M1 to M4 as shown in FIG. 4, and the mobile receivers M1 to M4 each have an identification code memory 23 in which the identification code is individually set, and this identification code. Code memory 23
The identification code comparison unit 15 as a comparison means for comparing the identification code set in step 1 with the identification code included in the transmission signals from the radio base stations B1 to B3, and the coincidence output of the identification code comparison unit 15 displays the call display. Display unit 1 as display means for performing
Including 7 and.

Further, the mobile receivers M1 to M4 have a display 25 as an optical display means for displaying character information.
The transmission signal transmitted from the wireless base stations B1 to B3 according to the baseband signal generated by the central station S includes this character information.

Radio base stations B1 to B3 and mobile receiver M
1 to M4, a plurality of hopping patterns are set in the hopping pattern memories 9 and 21, and the central station S receives the baseband signals transmitted to the respective radio base stations B1 to B3 via the fixed line. The radio base station B1 is provided with a hopping pattern information control unit 2 as a means for setting a code designating one of a plurality of hopping patterns.
.About.B3 includes a hopping pattern information extraction unit 7 as a means for selecting a hopping pattern of a transmission signal according to the designated code, and the mobile receivers M1 to M4 are included in the signals received from the radio base stations B1 to B3. A hopping pattern information extraction unit 19 is provided as a means for selecting a hopping pattern of a reception frequency according to a designated code.

Next, the monitoring receiver R1 will be described with reference to FIG. FIG. 6 is a block diagram of the main part of the monitoring receiver R1. At least one of the radio base stations B1 to B3 (here, B1) has spatial noise of a plurality of frequencies including a frequency to be next hopped during a period in which the transmission carrier frequency is one frequency according to the selected hopping pattern. The centralized station S is provided with a monitoring receiver R1 for monitoring the level, and a monitoring information transmitting unit 31 as means for transmitting the monitoring result of the monitoring receiver R1 to the central station S via the fixed line. According to the result, when the frequency to be hopped next has a noise level exceeding a specified value, a code designating one of the hopping patterns so as to include a frequency having a small noise level as a frequency to be hopped next is the baseband signal. The hopping pattern information control unit 2 is provided with a means for transmitting the information. The spatial noise level is measured by the noise level detector 29.

In the frequency hopping assumed in the embodiment of the present invention, the residence time of one frequency is 20 mS. Spatial noise level monitoring is 1m per frequency
Since it is possible with S, it is theoretically possible to monitor up to 20 hopping destinations in advance. actually,
Since it takes time to report the monitoring result and other times, 10 points are monitored in advance in the embodiment of the present invention.

Next, the operation at the time of starting the mobile receivers M1 to M4 will be described with reference to FIG. FIG. 7 is a diagram showing a hopping situation. The horizontal axis represents hopping frequency and the vertical axis represents time. The transmission signal shown in FIG. 4 is frequency-hopping by the hopping pattern as shown in FIG.
The transmission signal includes a control channel as shown in FIG. 4, and the mobile receiver (here, M1) to be activated receives the control channel, whereby the hopping pattern currently in use is received. You can get information.

Therefore, as shown in FIG. 7, the mobile receiver M
1 waits at any one of the hopping frequencies included in the hopping pattern, and waits for the timing at which the transmission signal is frequency hopping. In one embodiment of the present invention, one hopping pattern includes 20 hopping destinations. If the residence time at one location is 20 mS,
Since the hopping cycle is 400 mS, the mobile receiver M1 can start reception after a waiting time of approximately 0.5 seconds at the longest.

As shown in FIG. 1, since the fixed frequency radio base station B4 is also provided, the central station S can also receive a fixed frequency mobile receiver different from the frequency hopping communication system. The baseband signal can be transmitted as a wireless signal. In the embodiment of the present invention, the radio base station B4
Is transmitting a 280 MHz radio signal.

Since the frequency hopping communication system shown in the embodiment of the present invention can simplify the equipment, the equipment such as the airport shown in the conventional example transmits a small power transmission signal in synchronization. This is suitable when a large number of wireless base stations are arranged.

[0041]

As described above, according to the present invention,
The equipment of the radio base station can be simplified. Therefore, it is suitable for arranging a large number of radio base stations that synchronously transmit low power transmission signals in one system. It is also suitable for transmitting call information, voice information, character information, and other composite information.

Further, according to the present invention, the hopping frequency can be rationally selected with less interference. Further, it can be adapted to the radio paging communication system which has been conventionally installed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a main part of a centralized station.

FIG. 3 is a block diagram of a main part of a wireless base station.

FIG. 4 is a configuration diagram of a baseband signal or a transmission signal.

FIG. 5 is a block diagram of a main part of a mobile receiver.

FIG. 6 is a block diagram of a main part of a monitoring receiver.

FIG. 7 is a diagram showing a hopping situation.

FIG. 8 is an overall configuration diagram of a communication system arranged in an airport.

[Explanation of symbols]

 1 Baseband signal generation unit 2 Hopping pattern information control unit 3, 11 Transmission unit 5 Up converter 7, 19, 33 Hopping pattern information extraction unit 9, 21, 35 Hopping pattern memory 13, 27 Reception unit 15 Identification code comparison unit 17 Display Part 23 Identification code memory 25 Display 29 Noise level detection part 31 Monitoring information transmission part B, B1 to B4 Radio base station C Mobile station F Fixed station M1 to M4 Mobile receiver R1 Monitoring receiver S Centralized station

Claims (8)

[Claims] 1. A plurality of radio base stations transmitting a frequency hopping signal in which a carrier frequency changes according to a predetermined hopping pattern over time, and information of the hopping pattern is held in advance and the radio base station A plurality of mobile receivers that synchronously receive the frequency hopping signal transmitted by at least one of the plurality of mobile receivers; In a frequency hopping communication system including a centralized station that controls synchronization of frequency hopping signals transmitted by the wireless base stations, the centralized station is a signal to be transmitted simultaneously from the plurality of wireless base stations as a baseband signal. Means for generating and means for transmitting this baseband signal to the fixed line Provided, wherein the radio base station, a frequency hopping communication method comprising the up-converter for converting the baseband signal arriving from the fixed line to a frequency hopping signal that varies in accordance with the hopping pattern. 2. The transmission signal transmitted from the radio base station according to a baseband signal generated by the centralized station includes an identification code of the mobile receiver, and the mobile receiver individually has an identification code. A set memory means, a comparing means for comparing the identification code set in the memory means with an identification code included in a transmission signal from the radio base station, and a display for displaying a call by coincidence output of the comparing means. And a frequency hopping communication method. 3. The mobile receiver comprises optical display means for displaying character information, and the character information is included in a transmission signal transmitted from the radio base station according to a baseband signal generated by the central station. The frequency hopping communication system according to claim 1 or 2, further comprising: 4. A plurality of hopping patterns are set in the radio base station and the mobile receiver, and in the central station, a baseband signal transmitted to each radio base station via the fixed line is included. The wireless base station comprises means for setting a code designating one of the plurality of hopping patterns, the wireless base station comprises means for selecting a hopping pattern of a transmission signal according to the designated code, and the mobile receiver has the wireless base station. 4. The frequency hopping communication system according to claim 1, further comprising means for selecting a hopping pattern of a reception frequency according to the designated code included in the signal received from the station. 5. At least one of the radio base stations is provided with spatial noise levels of a plurality of frequencies including a frequency to be next hopped during a period in which a transmission carrier frequency is one frequency according to a selected hopping pattern. A monitoring receiver for monitoring, and means for transmitting the monitoring result of the monitoring receiver to the central station via the fixed line, the central station stipulates to the frequency to hop next according to the monitoring result. A means for transmitting a code specifying one of the hopping patterns in the baseband signal so that when a noise level exceeding a value is present, a frequency having a low noise level is included as a frequency to be hopped next. 4. The frequency hopping communication method described in 4. 6. At least one control channel is set in the baseband signal with a narrow frequency width, and the hopping pattern is limited to a small number of hopping frequencies of the control channel for all hopping frequencies. The centralized station is provided with means for transmitting a code designating one of the hopping patterns in the control channel, and the mobile receiver hops on the control channel when newly activated. There is provided a control means for fixing the reception frequency to one frequency and making it stand by, and performing the hopping of the reception frequency according to the hopping pattern when the code designating one of the hopping patterns is detected in the control channel. The frequency hopping communication system according to claim 4 or 5. 7. A mobile receiver used in the frequency hopping communication system according to claim 1. Description: 8. The frequency hopping communication system according to claim 1, further comprising at least one fixed frequency radio base station in which a fixed line is established between the centralized station and the frequency hopping communication system. The fixed frequency type wireless base station is provided with means for transmitting the baseband signal coming from the central station by a carrier wave of a fixed frequency.