JPH07235919A - Radio communication method using tdma system - Google Patents

Abstract

PURPOSE:To perform the bidirectional communication in the single frequency and with high articulation by sending the transmission signal including the control data on the bidirectional communication mode request at the answering side in a unidirectional communication mode by the operation of a keyboard by a request given to the calling side for transfer of data. CONSTITUTION:The high frequency signal received by an antenna 1 is inputted to a DSP 11 via a receiving part 3. In both unidirectional and bidirectional communication modes, a CPU 19 outputs the control data to a channel coder/ decoder 12 and converts the data by the DSP 11 together with the communication data received from a CODEC 21 or a data input/output interface 22. The converted data are superposed on the transmission signal sent from a VCO 15 by a converter 14 via a D/A converter 13 of a transmitting part 4. The transmission signal including the data signal is inputted to the antenna 1 via the amplifiers 16 and 17 end a switch 2. When the transfer of data is requested t0 the calling side from the answering side in a unidirectional. communication mode, a transmission signal including the control data requesting the bidirectional communication mode is transmitted through the antenna 1 by the operation of a keyboard 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to TDMA (Time Divis).
ion multiple access: relates to a bidirectional wireless communication method with a single frequency using a time division multiple access method.

[0002]

2. Description of the Related Art A wireless device has been developed and put into practical use for performing bidirectional communication on a single frequency for maintenance work in electric power companies. It is realized by narrowing the voice bandwidth in an analog manner.

[0003]

However, since such a mobile radio apparatus uses an analog system to narrow the voice bandwidth and enable bidirectional communication at a single frequency, it causes deterioration of sound quality and good clarity. There was a problem that I could not communicate with. Therefore, it is an object of the present invention to provide a wireless communication method capable of bidirectional communication with a single frequency and good clarity.

[0004]

The wireless communication method of the present invention uses a time division multiplexing connection system in which an assigned time slot is composed of a control slot for transmitting control data and a communication slot for transmitting communication data. In the wireless communication method described above, one of both communication stations transmits control data to the front end of the time slot, and the other station of both communication stations to the rear end of the time slot. Control data, and one station or the other station in the middle part of the time slot in one-way communication mode uses all of its communication slots to send full-rate communication data, and one station in the two-way communication mode. Uses half of its communication slots to send half-rate communication data, and then the other station uses the other half of the slots to transmit half-rate communication. It is characterized by transmitting the data.

[0005]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the TDMA mobile radio apparatus of the present invention shown in FIG. 1, the antenna 1 is a transmitting / receiving antenna, and a TDD (Time Division Duplex) system is adopted. The terminal of the antenna 1 is connected to either the receiving unit 3 or the transmitting unit 4 via the antenna switch 2. The selection of the antenna switch 2 on the receiving unit 3 side is in a steady state. In the receiving unit 3, the high frequency signal, which is a received signal from the antenna switch 2, receives a band limiting filter (BP
F) The band is limited by 5 and then supplied to the high frequency amplifier 6. The signal amplified by the high frequency amplifier 6 is supplied to the down converter 8 via the band limiting filter 7. The down converter 8 converts the supplied high frequency signal to V
The local oscillation signal from CO9 is mixed to generate an intermediate frequency signal. After the intermediate frequency signal output from the down converter 8 is digitized by the A / D converter 10,
It is supplied to a DSP (digital signal processor) 11. The DSP 11 detects the supplied digitized intermediate frequency signal, demodulates an information signal such as a voice signal and a control signal included in the received signal, and supplies the demodulated information signal to the channel coder / decoder 12. Further, the DSP 11 performs a modulation operation according to communication data, which is a digital information signal to be transmitted and is supplied from the channel coder / decoder 12, and supplies the modulation result to the transmission unit 4.

In the transmitter 4, the digital signal output from the DSP 11 is supplied to the up converter 14 via the D / A converter 13. Upconverter 14
Mixes the modulated signal with the oscillation signal from the VCO 15 and frequency-converts it to a frequency to be transmitted. The oscillation signal is amplified by the front stage amplifier 16 and further amplified by the power amplifier 17 to become a transmission signal. This transmission signal is supplied to the antenna 1 via the antenna switch 2.

The modulation and demodulation operations of the DSP 11 are CPU
It is controlled by (central processing unit) 19. The switching operation of the antenna switch 2, the oscillation frequencies of the VCOs 9 and 15 and the amplification operation of the power amplifier 17 are controlled by the operating state of the DSP 11. The CPU 19 controls the DSP 11 according to the operation from the keyboard 20, and also the channel coder / decoder 12 and the voice CODEC (codec).
21 to control each operation mode. The channel coder / decoder 12 operates as a coder that performs a predetermined code conversion on the digital audio signal supplied from the voice CODEC 21 or the digital data signal supplied from the data input / output interface 22, and the signal after the code conversion is performed. Are supplied to the DSP 11. Further, it operates as a decoder for decoding the demodulated digital signal supplied from the DSP 11 and supplies the decoded digital signal to the voice CODEC 21 or the data input / output interface 22. The voice CODEC 21 converts the analog audio signal from the microphone amplifier 23 into a digital audio signal of a predetermined format, converts the decoded digital audio signal from the channel coder / decoder 12 into an analog signal, and changes it into a speaker amplifier 24.
Supply to. A microphone 25 is connected to the microphone amplifier 23, and a speaker 26 is connected to the speaker amplifier 24.
Are connected.

In the mobile radio apparatus having such a configuration, for example, in the time slot assigned from the base station, the output of the power amplifier 17 of the transmitting unit 4 is increased at a predetermined timing as shown in the waveform of FIG. Later reduction is done. In FIG. 2, quadruple TD
The MA method is shown, and wireless communication is performed between the base station and the same mobile station at each position with the same slot number. The slot has a length of 20 msec, for example, and 320 bits of data are transmitted. In each slot, control channels (control data) of both stations for communication are located at both ends as schematically shown in FIG.

Communication modes include a unidirectional communication mode and a bidirectional communication mode. In either communication mode, the control channel of one station is located at the tip of the slot, and the control channel of the other station is the slot. Located at the tip.
As shown in FIG. 4, the data format in the slot of the unidirectional communication mode is such that the ramp of the transmission rising from one station (upstream) side, the unique word that becomes the synchronization signal, the control data, and the CRC (cyclic redundancy for error detection). Inspection), full-rate communication data, and the ramp of the transmission fall. After the ramp at the fall of transmission, a guard time of 8 bits is set. After the guard time, from the other station (downstream) side, the rising edge of the transmission, the unique word that becomes the synchronization signal, the control data, the CRC for error detection,
Then, the order of the ramp of the transmission falling edge is set. Further, a guard time of 8 bits is placed between the next slots. In the figure, the numbers in parentheses are the number of bits.

As shown in FIG. 5, the data format in the slot in the bidirectional communication mode is such that the ramp of the transmission rising from one station (upstream) side, the unique word to be the synchronizing signal, the control data, and the CRC for error detection. , Half-rate communication data, and the ramp of the transmission fall. After the ramp at the fall of transmission, a guard time of 8 bits is set. After the guard time, in the same way from the other station (downstream) side, the ramp of the transmission rising edge, the unique word that becomes the synchronization signal, the control data, the half-rate communication data, the CRC for error detection, and the ramp of the transmission falling edge in the same order. Becomes Further, a guard time of 8 bits is placed between the next slots.

In the data formats of the one-way communication mode and the two-way communication mode, the control data is the control channel data. The control data to be transmitted is first supplied from the CPU 19 to the channel coder / decoder 12, converted into the above data format together with the communication data from the voice CODEC 21 or the data input / output interface 22, and then supplied to the DSP 11.
Communication data is not included until the link is established. The DSP 11 performs data conversion on the supplied data signal by a modulation operation and supplies the data signal to the D / A converter 13. D
The data signal analogized by the / A converter 13 is superimposed on the oscillation signal from the VCO 15 by the up converter 14. The oscillation signal including the data signal is supplied to the pre-stage amplifier 16
Is amplified and further amplified by the power amplifier 17 to be a transmission signal, which is supplied to the antenna 1 via the antenna switch 2. On the other hand, the signal received by the antenna 1 is supplied to the down converter 8 via the antenna switch 2, the band limiting filter 5, the high frequency amplifier 6 and the band limiting filter 7. The down converter 8 mixes the supplied signal with the local oscillation signal from the VCO 9 to form an intermediate frequency signal, which is digitized by the A / D converter 10 and then supplied to the DSP 11. DSP11
The signal demodulated by is supplied to the channel coder / decoder 12. The channel coder / decoder 12 supplies control data to the CPU 19 and sends communication data to the voice CODEC.
21 or the data input / output interface 22.
That is, if the communication data is voice data, it is supplied to the voice CODEC 21, and if it is not voice data, it is supplied to the data input / output interface 22.

FIG. 6 shows the operation until communication is performed in the bidirectional communication mode. When communication is started, the caller operates the keyboard 20 to transmit a transmission signal including control data for requesting link establishment from the antenna 1 in the one-way communication mode. When the response side determines the link establishment request of the control data obtained from the received signal, the transmission signal including the control data of the link establishment response is transmitted from the antenna 1 in the one-way communication mode.
Upon receiving the link establishment response, the calling side starts communication in the one-way communication mode. Here, as shown in FIG. 4, full-rate communication data is included. On the responding side to the communication in the one-way communication mode, a full-rate communication response in the one-way communication mode is made by the control data.

During the communication in the one-way communication mode, if the response side desires data transmission to the calling side, a transmission signal including control data for requesting the two-way communication mode is transmitted from the antenna 1 by operating the keyboard 20. To be done. On the calling side, when the control data obtained from the reception signal determines the bidirectional communication mode request, the transmission signal including the control data of the bidirectional communication mode response is transmitted from the antenna 1. After the transmission of the transmission signal is completed, the communication mode is switched from the unidirectional communication mode to the bidirectional communication mode on the calling side. When the response side determines the bidirectional communication mode response from the received control data, it switches the communication mode to the bidirectional communication mode and starts communication in the bidirectional communication mode. Here, half-rate communication data is included as shown in FIG. 5, and the transmission time is about half of one time slot. When the communication in one slot in the bidirectional communication mode is completed, the responder generates a half-rate communication response in the bidirectional communication mode, and thereafter, the communication in the slot bidirectional communication mode in the assigned slot is repeated. Be done.

That is, when the CPU 19 of the response side device outputs the control data of the bidirectional communication mode request, it determines whether or not the control data is newly received. When new control data is obtained, it is determined whether or not the control data indicates a bidirectional communication mode response. When the bidirectional communication mode response is indicated, the operations of the channel coder / decoder 12 and the voice CODEC 21 are switched to the bidirectional communication mode. When the bidirectional communication mode response is not indicated, the channel coder / decoder 12 and the voice COD 21 are operated.
The operation of the DEC 21 is maintained in the unidirectional mode.

Further, when the CPU 19 of the calling side device obtains the control data of the bidirectional communication mode request, if communication in the bidirectional communication mode is not possible, the CPU 19 responds automatically or in response to an operation from the keyboard 20. And the channel coder / decoder 1
2 and the operation of the voice CODEC 21 are switched to the bidirectional communication mode.

Further, if a request for transition to the unidirectional communication mode is issued from one station during the bidirectional communication mode, and the other station agrees with the request, the same procedure as above is performed on the control channel to perform the unidirectional communication. It switches to the communication mode.

[0017]

As described above, in the wireless communication method using the TDMA system of the present invention, one of the communication stations transmits control data to the front end of the time slot and the rear end of the time slot. The other station of both communication stations transmits control data, and one station or the other station transmits full-rate communication data in the unidirectional communication mode in the middle part of the time slot, and in the bidirectional communication mode. One station sends half-rate communication data, then
Since the other station sends half-rate communication data,
Since the information is compressed by using the DSP, it is not necessary to narrow the voice bandwidth as in the conventional method, and it is possible to perform bidirectional communication with a single frequency and good intelligibility.

[Brief description of drawings]

FIG. 1 is a block diagram showing a wireless communication device to which a wireless communication method of the present invention is applied.

FIG. 2 is a diagram showing time slots used in TDMA-based information transmission.

FIG. 3 is a diagram showing a position of a control channel in a time slot.

FIG. 4 is a diagram showing a data format in a slot in a one-way communication mode.

FIG. 5 is a diagram showing a data format in a slot in a bidirectional communication mode.

FIG. 6 is a diagram showing an operation sequence until communication is performed in the bidirectional communication mode.

[Explanation of symbols for main parts]

 1 Antenna 3 Receiver 4 Transmitter 11 DSP 12 Channel Coder / Decoder 19 CPU 21 Voice CODEC

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area H04L 1/00 F 9371-5K

Claims (3)

[Claims] 1. A wireless communication method using a time division multiplex connection system, in which an assigned time slot is composed of a control slot for transmitting control data and a communication slot for transmitting communication data, the method comprising: One of the two communication stations transmits control data to the front end, and the other station of the two communication stations transmits control data to the rear end of the time slot. In the unidirectional communication mode in the middle part of the slot, the one station or the other station transmits full-rate communication data using all of the communication slots, and in the bidirectional communication mode, the one station Half of the half-rate communication data is transmitted, and then the other station uses the other half of the half-rate communication data. A wireless communication method comprising: 2. The two-way communication when the other station transmits control data indicating a two-way communication mode request in the one-way communication mode and the one station determines the two-way communication mode request from the received control data. A control data indicating a mode response is transmitted to shift to the two-way communication mode, and the other station shifts to the two-way communication mode when a two-way communication mode response is discriminated from the received control data. The wireless communication method according to Item 1. 3. When the one station transmits control data indicating a one-way communication mode request in the two-way communication mode, and the other station determines the one-way communication mode request from the received control data and responds to it. A feature that the control data indicating the unidirectional communication mode response is transmitted to shift to the unidirectional communication mode, and the one station shifts to the unidirectional communication mode when a unidirectional communication mode response is determined from the received control data. The wireless communication method according to claim 1.