JP3041186B2 - Data transmission equipment - Google Patents

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 a configuration of a conventional data transmission device. In FIG. 3, reference numeral 31 denotes a mobile station. Reference numeral 32 denotes a radio unit that processes a radio signal in a base station connected to the mobile station 31 by a radio signal. A modulation / demodulation unit 33 obtains a reception data signal from a reception signal from the radio unit 32 and generates a transmission signal to the radio unit 32 from a transmission data signal. Reference numeral 34 is connected to a modulation / demodulation unit 33 for performing error correction coding, scrambling coding operation, encryption and frame assembly on the transmission data signal, decoding error correction, scrambling decoding operation and encryption for the reception data signal. This is a code conversion unit that performs decoding of frames and decomposition of frames. A data conversion unit 35 is connected to the code conversion unit 34 and converts a signal of a wired network or a unique interface into 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, a downlink signal is converted into a control signal from a central control unit 36 or a signal encoded at an encoding speed transmitted by a radio unit at a data conversion unit 35, and is then subjected to error correction encoding or scrambling encoding at a code conversion unit 34. The data is subjected to operation, encryption, and frame assembly, and output to the modem 33. In the modem 33,
The input data is modulated and output to the radio unit 32. The radio unit 32 outputs a radio signal from the antenna to the mobile station 31 at a predetermined frequency and a predetermined transmission output power.

On the other hand, the uplink signal is delivered from the mobile station 31 to the base station as a radio signal only when it is necessary to transmit the signal from the mobile station 31, amplified and frequency converted by the radio section 32, and modulated and demodulated by the modem section 33. Convert to digital data. The converted data is subjected to decoding of an error correcting code, decoding of scrambling, and decoding of a code by a code conversion unit 34, and a frame is decomposed to extract necessary data.
Signal data such as voice is decoded by a data conversion unit 35 into information necessary for a wired network or a unique interface, and a control signal is transmitted to a central control unit 36. All of these operation timings are controlled by the timing control unit 37.

[0005]

However, in the above-mentioned conventional data transmission apparatus, when a plurality of base stations use the same frequency, radio waves collide and communication becomes impossible. A frequency to be used is assigned to each base station in advance. For this reason,
One base station frequently communicates with mobile stations, so the frequency is insufficient, and another base station may be idle without using the allocated frequency, effectively using the limited frequency There was a problem that it was not possible.

The present invention solves such a conventional problem, and provides an excellent data transmission apparatus capable of effectively using a limited radio wave while avoiding a frequency collision with another base station. 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 data while moving to and from a base station, wherein the base station is assigned to each base station. Set a time zone for searching for an available channel based on the ID number, search for a radio wave of a base station near the own station in the set time zone, and set a frequency not used by another base station to the own station. Are taken in as usable frequencies.

[0008]

According to the present invention, with the above arrangement, it is possible to set based on the ID numbers assigned to the respective base stations so that the time slots for searching for an empty channel do not overlap between the base stations.
When a certain base station is searching for a radio wave of a peripheral base station, it is guaranteed that all but the base station are in a normal operation state of communicating with the mobile station. Accordingly, each base station searches for radio waves of all other base stations that may cause interference around the own station by searching for an available channel, and fetches a frequency not used by the other base station as its own frequency. Thereby, limited radio waves can be effectively used while avoiding frequency collision with other base stations.

[0009]

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 apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a mobile station. Reference numeral 2 denotes a radio unit for performing radio signal processing in a base station connected to the mobile station 1 by radio signals. A modulation / demodulation unit 3 obtains a reception data signal from a reception signal from the radio unit 2 and generates a transmission signal to the radio unit 2 from a transmission data signal. 4 is connected to the modulation / demodulation unit 3,
Performs error correction coding, scramble coding operation, encryption, and frame assembly on transmission data signals, and performs error correction decoding, scramble decoding operation, encryption decoding, and frame decomposition on received data signals. It is a code conversion unit. Reference numeral 5 denotes a data conversion unit which is connected to the code conversion unit 4 and converts a signal of a wired network or a unique interface into 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 the detected frequency of the other base station can be used as its own frequency. It is. Reference numeral 7 denotes a timing control unit which 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 nearby base stations in a time zone set for the base station based on an ID number assigned to each base station and detects a frequency not used by another base station. And is connected to the central control unit 6 and the timing control unit 7. Reference numeral 9 denotes an ID number registration unit for registering an ID number unique to each base station and setting a time zone that does not overlap with other base stations based on the ID number. The ID number registration unit 9 is connected to the central control unit 6.

Next, the operation of the above embodiment will be described.
In FIG. 1, a downlink signal is converted into a control signal from a central control unit 6 or a signal encoded at an encoding rate transmitted from a radio unit 2 by a data conversion unit 5, into an error correction encoding or a scramble code by a code conversion unit 4. The data is subjected to an encryption operation or encryption and output to the modulation / demodulation unit 3. The modulation / demodulation unit 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 transmission from the mobile station 1 is necessary, and the radio section 2 performs amplification and frequency conversion.
The data is converted into digital data by the modem unit 3. The converted data is subjected to decoding of an error correction code, decoding of scrambling, and decoding of an encryption by the code conversion unit 4 to decompose a frame to extract necessary data. The data is decoded by the data converter 5 into a signal necessary for a wired network or a unique interface, and the control signal is transmitted to the central controller 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 constantly transmitted, while The existence time of the uplink signal from the station to the base station is periodically defined uniquely for each mobile station. Therefore, the base station prepares for the receiving 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 is transmitted only when the mobile station is necessary. In addition, since transmission errors are taken into account, the uplink signal to the base station confirms its response, proceeds to the next procedure, and retransmits if it cannot be confirmed.

In the present embodiment, attention is paid to the fact that an uplink signal from the mobile station 1 to the base station is not always present, and the base station receives radio waves from other neighboring base stations, If there is, it is intended to use the radio wave effectively by capturing it as a frequency that can be used by itself.

When each base station shifts to an empty channel search mode for searching for radio waves from neighboring base stations in an appropriate time zone and interrupts communication with the mobile station, a certain base station searches for an empty channel. Sometimes, when the base stations in the vicinity are also searching for an available channel, it is not possible to search for radio waves of frequencies used by the partner base stations. Therefore, in the present embodiment, the ID number registration unit 9 uses the ID number uniquely assigned to each base station to set the time zone of the free channel search of each base station so as not to overlap. As shown in FIG. 2, the scan control unit 8 of the station efficiently searches for an empty channel during the time zone set for the own station, and while a certain base station searches for an empty channel, The other base stations communicate with the mobile station in a normal operation state without searching for an empty channel.

The central control unit 6 performs a series of these processes.
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 in accordance with 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 central control unit 6 determines whether or not the frequency of another base station detected by the scan control unit 8 is usable as its own frequency. The base station notifies the other base station of the borrowing and communicates with the mobile station using the frequency. The search and capture of the radio wave of the peripheral base station can be performed at any time, but it is desirable to always perform the search when the system is started.

[0016]

As described above, according to the present invention, the base station sets a time zone for searching for an available channel based on the ID number assigned to each base station, and the base station sets its own time zone in the set time zone. The base station near the base station is searched for radio waves and frequencies not used by other base stations are taken in as usable frequencies of the own station, so limited radio waves are avoided while avoiding collision with other base stations. Can be effectively used.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating 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 illustrating operation timings of the data transmission device according to the 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 (72) Inventor Kazuhiro Umezu 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. (56) References A) JP-A-6-53901 (JP, A) JP-A-7-203518 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04Q 7/00-7/38 H04B 7 / 24-7/26 102

Claims (3)

(57) [Claims] A mobile station capable of transmitting and receiving data while moving to and from a base station, wherein the base station sets a time zone for searching for an available channel based on an ID number assigned to each base station. A data transmission device comprising means for searching for radio waves of base stations near the own station in 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 data while moving to and from a base station, wherein the base station converts a radio signal and a data string by connecting to a radio unit for handling a high-frequency signal. And a code converter connected to the modulator / demodulator for coding / decoding data and assembling / disassembling slots, and connected to the code converter to communicate with a signal of a wired network or a unique interface by radio signals. A data converter for converting digital data, and a base station for determining operation and communicating control signals with the mobile station;
A central control unit that determines whether the detected frequency of the other base station can be used as the frequency of the own station, and 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 zone for performing an empty channel search based on the ID number assigned to each base station, and an ID number registration unit set based on the ID number assigned to each base station A data transmission device comprising: a scan control unit that searches radio waves of a base station near the own station in a time zone and detects a frequency not used by another base station. 3. The data transmission device according to claim 2, wherein the data transmission device is applied to a time division multiple access system.