JPH06224954A - Data communication system and its equipment using differential phase shift modulation - Google Patents

Abstract

PURPOSE:To attain the communication at an optimum communication speed by allowing a sender side to designate an optional operating function and to send information depending on line quality at communication and allowing a receiver side to discriminate automatically the operating function of the sender side and to make the function coincident with the operating function of the sender side and to make demodulation. CONSTITUTION:A sender side equipment 10 has a transmission data buffer 11 and an FDM-4/8 phase DPSK modulator 13. The equipment 10 inserts a 4/8 phase discrimination pattern between a synchronizing signal and a data tone based on a received 4/8 phase switching signal to form a frame. The receiver side equipment receives a special signal such as a synchronizing signal, a doppler tone or a signal for line quality discrimination sent from the equipment 10 as a means to discriminate whether the communication quality is excellent or not. The S/N or the like of the received signal is detected and the S/N is returned to the sender side, and the equipment 10 discriminates which polyphase is to be used based on the returned signal. A phase shift angle of 45 deg. for 4-phase or a phase shift angle of 202.5 deg. is adopted for 8-phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system and apparatus using differential phase modulation.

[0002]

2. Description of the Related Art In recent years, differential phase shift (DPSK; Dif).
ferrental Phase Shift Key
ing) various data communication systems and devices using the modulation system have been proposed. Especially, in the communication in the HF band or the like, the radio wave propagation becomes non-uniform within the frequency band due to the effects of fading and multipath, and the modulation speed cannot be increased. Therefore, when performing high-speed data communication, Is divided into a plurality of sub-channels, and information is divided into respective sub-channels for transmission and then FDM (Frequency).
y Division Multiplex-DPSK system is used.

6 to 7 show the case of the four-phase modulation method. First, referring to FIG. 6, in the transmitting side device 110, as shown in FIG.
0 and the receiving-side device 120 are synchronized with each other by transmitting a synchronization signal S11, and subsequently, the data S13 from the transmission data buffer 111 is fetched and modulated by the FDM-4 phase DPSK modulator 113, and the transmitter 115 and the antenna. Send via 117. The transmission data is taken in 32 bit units for each modulation frame period, and 2 bits are allocated to 16 data tones shown in FIG. 9, and each tone is shifted to the phase angle shown in FIG. 10 with respect to the phase of the previous modulation period. Send.

On the other hand, in the receiving-side device 120, first, the synchronization detecting unit 1 detects the transmission data input via the receiver 123.
When the synchronization signal S11 is detected at 25, the clock timing signal of the phase shift on the transmission side is detected, and the clock timing of the reception side is synchronized with the timing of the phase shift on the transmission side. Subsequently, the phase measuring unit 127 measures the phase of the received signal for each tone in accordance with the modulation timing, determines which quadrant in FIG. 10 the transfer shift angle of each tone is in, and outputs 2-bit data. Determined, 16 tones total 32
The bit is sent to the reception data buffer 133 after the data is decoded by the data decoding unit 129.

However, HF (High Freq
Since the fluctuation range of the line quality is large in the case of "uency) line", there is a case where 8-phase DPSK that can be used when the line quality is good can be used depending on the used frequency and time zone, but the line quality deteriorates. Considering time, 4-phase D
Since PSK is used, it is not possible to improve the line utilization efficiency. Further, in order to change the modulation method according to the condition of the line quality, it is necessary to prepare a plurality of modulators and demodulators, and the hardware becomes large, which is disadvantageous in terms of cost.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a data communication system and apparatus using DPSK modulation, which can appropriately switch phases according to line quality. .

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the first invention of the present application is a program processing of a multi-phase modulation operation function corresponding to a plurality of phases in a differential phase shift keying type modem using multi-frequency multi-tone. According to the line quality situation at the time of communication, the transmitting side specifies any one of the operating functions and transmits information, and the receiving side automatically determines the operating function of the transmitting side by the received waveform, It is characterized in that the communication capacity according to the line quality state is secured by performing demodulation in conformity with that on the transmission side. Further, a second invention of the present application is a data communication system using differential phase shift keying, in which communication is performed by switching between a first phase and a second phase according to a line quality state, and in a data communication system, In the case of the first phase, the predetermined frame after the sync signal has all the phase shift angles of each tone in the first phase.
Of the phase determination pattern transmitted as the angle of the tone, and in the case of the second phase, a predetermined frame after the synchronization signal is inserted with the phase determination pattern transmitted with all the phase shift angles of the tones as the second angle. Characterize.

A third aspect of the present invention is a quality detecting means for detecting a line quality state, and a phase for switching between the first phase and the second phase according to the line quality state detected by the quality detecting means. Phase switching signal output means for outputting a switching signal and a phase forming a frame by inserting a predetermined phase determination pattern corresponding to the phase switching signal output from the phase switching signal output means between the synchronization signal and the data. And a judgment pattern inserting means. Furthermore, the fourth invention of the present application is
Phase determination pattern detection means for detecting a phase determination pattern inserted between the synchronization signal of the input communication signal and the data, and the first phase modulation method corresponding to the phase determined by the phase determination pattern detection means. And a switching means for switching between the second phase modulation method and the second phase modulation method.

[0009]

In the data communication system using the differential phase shift keying modulation of the first invention of the present application, the modem is provided with the polyphase modulation operation function corresponding to a plurality of phases by the program processing, and the line quality condition at the time of communication is met. , The transmitting side device specifies any one of the operating functions and transmits information, and the receiving side device automatically determines the operating function of the transmitting side based on the received waveform and sets the modulation method of the transmitting side. Match. In the data communication system using the differential phase shift keying modulation of the second invention of the present application, in the case of the first phase, the predetermined frame after the sync signal is the phase shift angle of each tone between the sync signal and the data. It is possible to distinguish between the first phase and the second phase by inserting the phase determination pattern transmitted as all the first angles and the phase determination pattern similarly transmitted as the second angle in the case of the second phase. As such, communication is performed by appropriately switching between the first phase and the second phase according to the line quality state. A data transmitting apparatus using differential phase shift keying modulation according to a third aspect of the present invention outputs a phase switching signal for switching between the first phase and the second phase according to the line quality state detected by the quality detecting means. Then, a predetermined phase determination pattern corresponding to the phase switching signal is inserted between the synchronization signal and the data to form a frame and the frame is transmitted. A data receiving device using differential phase shift keying modulation according to a fourth aspect of the present invention uses a first phase modulation method in accordance with a phase determination pattern inserted between a synchronization signal of an input communication signal and data. Reception is performed by switching between the second phase modulation method.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the embodiments shown in the drawings. FIG. 1 is a configuration diagram showing an embodiment in which a data communication method using DPSK modulation according to the present invention is applied to a transmission side device 10, and FIG. 2 is a reception side device 20 thereof. In this embodiment, 4-phase and 8-phase DPSK
The case of switching the modulation method will be described as an example. First, the configuration of the transmission side device 10 will be described with reference to FIG. The transmission side device 10 in this embodiment includes a transmission data buffer 11,
FDM-4 / connected to this transmission data buffer 11
8 phase DPSK modulator 13 and this FDM-4 / 8 phase DP
The transmitter 15 is connected to the SK modulator 13, and the transmitting antenna 17 is connected to the transmitter 15. Further, the data to be transmitted is the transmission data buffer 11
The 4/8 phase switching signal for switching between the 4 phase and the 8 phase is input to the transmission data buffer 11 and the FDM-4 / 8 phase DPSK modulator 13.

Next, the configuration of the receiving side device 20 will be described with reference to FIG. Similarly, the receiving side device 20 receives the receiving antenna 2
1 and a receiver 23 connected to this receiving antenna 21
And a synchronization detecting section 25 and a phase measuring section 27 connected to the receiver 23, and the synchronization detecting section 25 and the phase measuring section 2
7, a 4/8 phase determination unit 31, a data decoding unit 29 connected to the 4/8 phase determination unit 31 and the phase measuring unit 27, and a reception data buffer connected to the data decoding unit 29. 33. In the transmission sequence used in this embodiment, as shown in FIG. 3, a 4/8 phase judgment pattern S3 is provided between the synchronizing signal S1 and the data tone S5.

Next, the operation of this embodiment will be described with reference to FIGS. First, the transmitting side device 10 inserts a 4/8 phase determination pattern S3 between the sync signal S1 and the data tone S5 as shown in FIG. Make up. At this time, as a means for determining whether the communication quality at that time is good or bad at the transmitting side device 10, for example, a synchronization signal transmitted from the transmitting side device 10 at the beginning of communication, a Doppler tone, or a special for determining the line quality is used. Signal is received by the receiving side device 20, the S / N value etc. of the received signal is detected and the S / N value etc. is returned to the transmitting side, and further the transmitting side device 10 is based on this return signal. There is a method for determining which polyphase is used. Here, in the case of four phases, the phase shift angle of each tone is transmitted as all 45 degrees (first quadrant) in several frames after the synchronization signal.

In the case of eight phases, the phase shift angle of each tone is transmitted as the angle 202.5 degrees (third quadrant) shown by A in FIG. 4 for several frames after the synchronization signal. On the other hand, on the receiving side, when the synchronizing signal S1 is detected, the amount of phase shift of each data tone S5 of the following several frames is measured,
Based on the result, the 4/8 phase determination of the received signal is performed, and the 4-phase (FIG. 10) or the 8-phase (FIG. 4) demodulation for the subsequent data is performed. The 4/8 phase judgment is based on the number of transmissions and the number of tones of the 4/8 phase judgment pattern S3 to determine whether the phase angle measured for each tone is in the area A or the area B shown in FIG. Done by doing.

As described above, in this embodiment, in the wireless communication using the modem of the differential phase modulation system using multi-frequency multi-tone, the digital signal processing technique is used by using the conventional modulation circuit and demodulation circuit. , 2 phases to the modem, 4
The multi-phase modulation operation function corresponding to a plurality of arbitrary phases such as eight phases and eight phases is realized by program processing using a high-speed microcomputer such as DSP. As a result, with the hardware configuration and cost that are almost the same as before, depending on the line quality situation at the time of communication, the transmitting side specifies any one of the operating functions and transmits information, and the receiving side receives the received waveform. By this, the communication function that automatically determines the operation function of the transmission side and matches it with that of the transmission side and demodulates, thereby ensuring the communication capacity according to the line quality state is realized.

Further, FDM-DP of 4/8 phase modulation operation
The SK modulator / demodulator can also be realized by one piece of hardware. In addition, in the present embodiment, in order to perform communication according to the status of the transmission path, the transmission side device sends information on the modulation system to the reception side device prior to data transmission, and the reception side device responds to the transmission side modulation system. The communication method for demodulation is the conventional 4-phase DP
With a circuit equivalent to the SK modulator / demodulator, it is possible to realize a call with a modulation method suitable for the line quality.

[0016]

As described above, the present invention provides DPSK.
Since it is possible to realize a means for transmitting and receiving by changing the modulation method of modulation to 4/8 phase without adding hardware, by combining with the communication such as ARQ method, it is always possible to optimize transmission according to the state of the transmission path. This is very effective for speed communication and improving the utilization efficiency of the transmission path.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a transmission side apparatus of the present invention.

FIG. 2 is a block diagram showing an embodiment of a receiving side apparatus of the present invention.

FIG. 3 is a diagram showing a transmission sequence of the present invention.

FIG. 4 is a diagram showing an example of correspondence between 3 bits of data and a phase shift angle.

FIG. 5 is a diagram illustrating an example of determination of 4/8 phase.

FIG. 6 is a block diagram showing an example of a conventional transmission side apparatus.

FIG. 7 is a block diagram showing an example of a conventional receiving side device.

FIG. 8 is a diagram showing a conventional transmission sequence.

FIG. 9 is a diagram showing a frequency array of tones.

FIG. 10 is a diagram showing an example of correspondence between 2 bits of data and a phase shift angle.

[Explanation of symbols]

 11 Transmitted Data Buffer 13 FDM-4 / 8 Phase DPSK Modulator 15 Transmitter 17 Transmitted Antenna 21 Received Antenna 23 Receiver 25 Sync Detecting Section 27 Phase Measuring Section 29 Data Decoding Section 31 4/8 Phase Determining Section 33 Received Data Buffer

Claims (4)

[Claims] 1. A differential phase shift keying type modem using multi-frequency multi-tone is provided with a multi-phase modulation operation function corresponding to a plurality of phases by program processing, and transmission is performed according to a line quality condition during communication. The transmission side specifies the operation function of any one of them and transmits the information, and the reception side automatically determines the operation function of the transmission side from the received waveform, and matches the demodulation with that of the transmission side to demodulate the line quality. A data communication method using differential phase modulation, which ensures a communication capacity according to the state. 2. A data communication system using differential phase shift keying, in which communication is performed by switching between a first phase and a second phase in accordance with a line quality state, and a first signal is provided between a synchronization signal and data. In the case of a phase, a predetermined frame after the sync signal has a phase determination pattern in which all the phase shift angles of the tones are transmitted as a first angle, and in the case of the second phase, a predetermined frame after the sync signal has a phase determination pattern. A data communication system using differential phase shift keying, which inserts a phase determination pattern transmitted with all phase shift angles of tones as second angles. 3. A quality detecting means for detecting a line quality state, and a phase switching for outputting a phase switching signal for switching between a first phase and a second phase according to the line quality state detected by the quality detecting means. Signal output means, and phase determination pattern insertion means for forming a frame by inserting a predetermined phase determination pattern corresponding to the phase switching signal output from the phase switching signal output means between the synchronization signal and the data. A data transmission apparatus using differential phase shift keying, which comprises: 4. A phase determination pattern detecting means for detecting a phase determination pattern inserted between a synchronizing signal of an input communication signal and data, and a phase determination pattern detecting means corresponding to the phase determined by the phase determination pattern detecting means. A data receiving apparatus using differential phase shift keying modulation, comprising: switching means for switching between a first phase modulation method and a second phase modulation method.