JPH07274237A - Data transmitter - Google Patents

Abstract

PURPOSE:To effectively utilize a limited radio wave while avoiding collision of frequencies with other base station. CONSTITUTION:The transmitter is provided with an ID number registration section 9 setting a time zone for idle channel retrieval based on an ID number allocated to each base station, a scan control section 8 retrieving a radio wave of a base station around its own station for a set time zone to detect a frequency not used by other base station, and a central control section 6 discriminating whether or not the detected frequency is used for a frequency of its own frequency and makes communication with the mobile station 1 by using the frequency when the detected frequency is available.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device used for a digital car telephone or the like.

[0002]

2. Description of the Related Art FIG. 3 shows the configuration of a conventional data transmission device. In FIG. 3, reference numeral 31 is a mobile station. Reference numeral 32 denotes a wireless unit that processes a wireless signal in a base station connected to the mobile station 31 by a wireless signal. Reference numeral 33 denotes a modulation / demodulation unit that obtains a reception data signal from a reception signal from the wireless unit 32 or creates a transmission signal from the transmission data signal to the wireless unit 32. Reference numeral 34 is connected to the modulator / demodulator 33 to perform error correction coding, scramble coding operation, encryption and frame assembly on the transmission data signal, and error correction decoding and scramble decoding operation and encryption on the reception data signal. This is a code conversion unit that performs the decoding and the frame decomposition. A data conversion unit 35 is connected to the code conversion unit 34 and converts a signal of a wired network or an original interface and digital data communicated by a wireless signal. A central control unit 36 determines the operation of the base station and communicates control signals with the mobile station 31. A timing control unit 37 controls the operation timing of the base station and interfaces signals between the central control unit 36 and other units.

Next, the operation of the above conventional example will be described.
In FIG. 3, the downlink signal is a control signal from the central control unit 36 or a signal encoded by the data conversion unit 35 at an encoding rate to be transmitted by the radio unit, and the code conversion unit 34 performs error correction encoding or scramble encoding. It is output to the modulator / demodulator 33 after being subjected to operations, encryption, and frame assembly. In the modulator / demodulator 33,
The input data is modulated and output to the wireless unit 32, and the wireless unit 32 outputs a radio wave signal from the antenna to the mobile station 31 with a predetermined transmission output power at a predetermined frequency.

On the other hand, the upstream signal is delivered from the mobile station 31 to the base station as a radio signal only when it needs to be transmitted from the mobile station 31, is amplified and frequency-converted by the radio section 32, and is then modulated by the modulation / demodulation section 33. Convert to digital data. For the converted data, the code conversion unit 34 performs error correction code decoding, scramble decoding, and cipher decoding, and performs frame decomposition to extract necessary data,
The data of the signal such as voice is decoded by the data conversion unit 35 into information required for the wired network or the unique interface, and the control signal is transmitted to the central control unit 36. The timing controller 37 controls all of these operation timings.

[0005]

However, in the above-mentioned conventional data transmission apparatus, when a plurality of base stations use the same frequency, radio waves collide with each other and communication cannot be performed. A frequency used for each base station is assigned in advance. For this reason,
One base station frequently communicates with mobile stations, so the frequency may be insufficient, and another base station may be idle without using the assigned frequency, making effective use of limited frequencies. There was a problem that I could not.

The present invention solves such a conventional problem, and provides an excellent data transmission apparatus capable of effectively utilizing limited radio waves while avoiding frequency collision with other base stations. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention comprises a mobile station capable of transmitting and receiving while moving with a base station, and the base station is assigned to each base station. Set a time zone for performing a free channel search based on the ID number, search for radio waves from base stations in the vicinity of your own station during this set time zone, and search for frequencies not used by other base stations. It is designed to be captured as a usable frequency of.

[0008]

With the above arrangement, the present invention can be set so that the time slots for free channel search do not overlap between base stations based on the ID numbers assigned to each base station.
When a base station is searching for radio waves of neighboring base stations, it is guaranteed that all but the base station are in the normal operating state in which communication with the mobile station is performed. Therefore, each base station searches for radio waves of all other base stations that may cause interference in the vicinity of the own station by searching for a free channel, and takes in a frequency not used by the other base station as its own frequency. As a result, it is possible to effectively use limited radio waves while avoiding frequency collision with other base stations.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a part of the configuration of a data transmission device according to an embodiment of the present invention. In FIG. 1, 1 is a mobile station. Reference numeral 2 denotes a wireless unit that processes a wireless signal in a base station connected to the mobile station 1 by a wireless signal. Reference numeral 3 denotes a modulation / demodulation unit that obtains a reception data signal from the reception signal from the radio unit 2 or creates a transmission signal from the transmission data signal to the radio unit 2. 4 is connected to the modem unit 3,
Performs error correction coding, scramble coding operation, encryption, and frame assembly on the transmitted data signal, and performs error correction decoding, scramble decoding operation, cipher decoding, and frame decomposition on the received data signal. It is a code conversion unit. Reference numeral 5 is a data conversion unit that is connected to the code conversion unit 4 and performs conversion between a signal of a wired network or an original interface and digital data communicated by a wireless signal. A central control unit 6 determines the operation of the base station, communicates control signals with the mobile station 1, and determines whether or not the detected frequency of another base station can be used as its own frequency. Is. A timing control unit 7 controls the operation timing of the base station and interfaces signals between the central control unit 6 and other units. Reference numeral 8 denotes a scan control unit that searches for radio waves of surrounding base stations in a time zone set for the base station based on the ID number assigned to each base station to detect frequencies not used by other base stations. And is connected to the central controller 6 and the timing controller 7. Reference numeral 9 is an ID number registration unit that registers an ID number unique to each base station and sets a time zone that does not overlap with other base stations based on this, and is connected to the central control unit 6.

Next, the operation of the above embodiment will be described.
In FIG. 1, the downlink signal is a control signal from the central control unit 6 or a signal encoded by the data conversion unit 5 to the encoding rate transmitted from the radio unit 2, and the code conversion unit 4 performs error correction encoding or scrambling code. It is output to the modulator / demodulator 3 after being encrypted and encrypted. The modulator / demodulator 3 modulates the input data and outputs the modulated data to the radio unit 2. The radio unit 2 outputs a radio signal from the antenna to the mobile station 1 with a predetermined transmission output power at a predetermined frequency.

On the other hand, the uplink signal is delivered from the mobile station 1 to the base station as a radio signal only when the mobile station 1 needs to transmit the signal, and the radio section 2 amplifies and frequency-converts it.
The modulator / demodulator 3 converts the data into digital data. For the converted data, the code conversion unit 4 decodes the error correction code, the scramble, and the cipher, and decomposes the frame to extract the necessary data. The data conversion unit 5 decodes the signal into a signal required for a wired network or a unique interface, and the control signal is transmitted to the central control unit 6.

In a time division multiple access (TDMA) system represented by a PDC system which is a Japanese standard digital car telephone system, a downlink signal from a base station to a mobile station is always transmitted, while a mobile station is a mobile station. The upstream signal from the station to the base station has a time period in which it is periodically specified uniquely to each mobile station. Therefore, the base station prepares for the reception operation regardless of the presence or absence of the burst from the mobile station at that time, but the uplink signal does not always exist, and the mobile station transmits only when necessary. Further, since transmission error is taken into consideration, the system is such that the upstream signal to the base station confirms its response and proceeds to the next procedure, and if it cannot be confirmed, it is retransmitted.

Therefore, in the present embodiment, attention is paid to the fact that the uplink signal from the mobile station 1 to the base station does not always exist, and the base station receives radio waves from other peripheral base stations and has a vacant frequency. If so, the radio waves are effectively used by incorporating them as frequencies that can be used by the user.

When each base station shifts to a free channel search mode in which it searches for radio waves of neighboring base stations at an appropriate time and communication with the mobile station is interrupted, a certain base station searches for a free channel. At this time, when the base stations in the vicinity of the base station are also searching for a free channel, it is not possible to search for radio waves of the frequencies used by the other base stations. Therefore, in the present embodiment, the ID number registration unit 9 uses the ID numbers uniquely assigned to the respective base stations to set the time slots of the empty channel search of the respective base stations so that they do not overlap with each other. As shown in FIG. 2, the scan control unit 8 of the station efficiently searches for a free channel during the time zone set for the local station, and while a base station is searching for a free channel, The other base stations communicate with the mobile station in a normal operating state without searching for a free channel.

In the series of these processes, the central control unit 6 performs I
The set time zone is obtained from the D number registration unit 9 and the scan control unit 8
Is transmitted to the timing control unit 7 according to an instruction from the central control unit 6, and the timing control unit 7 controls all operation timings including other operations as a normal base station. The frequency of another base station detected by the scan control unit 8 is determined by the central control unit 6 as to whether or not it can be used as the frequency of its own station, and if it is available, the frequency of The other base station is notified that it will be rented, and the frequency is used to communicate with the mobile station. It should be noted that the search and acquisition of the radio waves of the peripheral base stations can be performed at any time, but it is desirable to perform them at the time of system startup.

[0016]

As described above, according to the present invention, a base station sets a time zone in which a free channel is searched based on an ID number assigned to each base station, and the own station is set in the set time zone. Since radio waves of base stations in the vicinity of are searched for and frequencies that are not used by other base stations are taken in as frequencies that can be used by the local station, limited radio waves can be avoided while avoiding collisions with other base stations. Can be effectively used.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a part of a base station of a data transmission device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the operation timing of the data transmission device of the present embodiment.

FIG. 3 is a schematic block diagram showing a part of a base station of a conventional data transmission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mobile station 2 Radio part 3 Modulation / demodulation part 4 Code conversion part 5 Data conversion part 6 Central control part 7 Timing control part 8 Scan control part 9 ID number registration part

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location 109 M (72) Inventor Kazuhiro Umezu 4-3-1, Tsunashima-higashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Within the corporation

Claims (3)

[Claims] 1. A mobile station capable of transmitting and receiving while moving to and from a base station, wherein the base station sets a time zone in which a free channel search is performed based on an ID number assigned to each base station. A data transmission apparatus comprising means for searching for radio waves of a base station around the own station during the set time zone and taking in a frequency not used by another base station as a usable frequency of the own station. 2. A mobile station capable of transmitting and receiving while moving to and from a base station, wherein the base station is connected to the radio unit for handling high frequency signals, and is connected to the radio unit to convert radio signals and data strings. A modulation / demodulation unit for performing, a code conversion unit connected to the modulation / demodulation unit for encoding / decoding data and assembling / disassembling slots, and connected to the code conversion unit for communicating with a signal of a wired network or a unique interface by a wireless signal. A data converter that converts digital data, determines the operation of the base station, and communicates control signals with the mobile station.
A central control unit that determines whether or not the detected frequency of another base station can be used as its own frequency, controls the operation timing of the base station, and interfaces signals between the central control unit and other units. A timing control unit, an ID number registration unit that sets a time slot in which a free channel is searched based on an ID number assigned to each base station, and an ID number assigned to each base station A data transmission device comprising: a scan control unit that searches for radio waves of a base station around the own station during a time zone to detect a frequency not used by another base station. 3. The data transmission device according to claim 2, which is applied to a time division multiple access system.