JP2002359657A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system that suppresses power consumption of a receiver so as to extend the operating time. SOLUTION: The communication system comprises a transmitter 1 that transmits a multi-value QAM signal using 1st information having large information quantities and 2nd information having small information quantities; a QAM receiver 13 that is provided with a linear amplifier for demodulating a multi- value QAM signal to extract the 1st and 2nd information items and a QAM demodulator; and a PSK receiver 20 that is provided with a nonlinear amplifier for demodulating a polyphase PSK signal to extract only the 2nd information and a PSK demodulator. The communication system generates a signal to be modulated in a way that the 2nd information is arranged on the arranged symbols of the multi-value QAM signal and also on the arranged symbols of the polyphase PSK signal and the 1st information is placed on the arranged symbols of the multi-value QAM signal, and modulates the signal to be modulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system of a wireless communication system for performing one-to-many opposed communication.

[0002]

2. Description of the Related Art FIG. 4 is a structural explanatory view showing a conventional communication system. In the figure, 1 is a transmitting device, 2 is a multiplexed signal generating device (MLT1), 3 is a serial / parallel converter (SLT).
/ P), 4 is a quadrature modulator (MOD), 5 is a terminal for inputting first information, 6 is a terminal for inputting second information, 7 is a transmitting antenna, 8 is a first receiving antenna, and 9 is a first receiving antenna. Linear amplifier (L
in), 10 is a QAM demodulator (DEM), 11 is the first
, A parallel / serial converter (P / S) 12, a first multiplexed signal demultiplexer (MLT 2), 13 a first QAM receiver, 14 a terminal for outputting first information, 15 a second terminal A first terminal for outputting information, 16 a second reception antenna, 22 a second QAM receiver, 23 a second multiplexed signal demultiplexer (MLT3), and 24 a third output second information Terminal.

That is, the multiplexed signal generator 2 of the transmitter 1 transmits a frame containing the first information having a large amount of information input from the terminal 5 and the second information having a small amount of information input from the terminal 6. The multiplexed frame is multiplexed in a time division manner to generate a multiplexed signal, which is output to the serial / parallel converter 3. The serial / parallel converter 3 converts the multiplexed signal input from the multiplexed signal generator 2 into 16 QAM
The I signal converted into a modulated wave signal, and one of the orthogonal carriers
The signal is converted into a Q signal converted into a 6QAM modulated wave signal and output to the quadrature modulator 4. The quadrature modulator 4 converts the I signal and the Q signal input from the serial / parallel
The AM-modulated multi-level QAM modulated signal is transmitted from the transmitting antenna 7. On the other hand, in the first QAM receiving device 13 for extracting the first information and the second information, the multi-level QAM modulated signal transmitted from the transmitting device 1 is received by the first receiving antenna 8 and input to the linear amplifier 9. . The linear amplifier 9 amplifies the multi-level QAM modulated signal and outputs it to the QAM demodulator 10. QA
The M demodulator 10 receives the multilevel QA input from the linear amplifier 9
The M-modulated signal is demodulated into an I signal and a Q signal, and output to the first parallel / serial converter 11. The first parallel / serial converter 11 converts the I signal and the Q signal input from the QAM demodulator 10 into a multiplexed signal and outputs the multiplexed signal to the first multiplexed signal separator 12. The first multiplex signal separation device 12 separates the multiplex signal input from the first parallel / serial converter 11 and outputs first information to a terminal 14 and outputs second information to a terminal 15.

Further, a second Q for extracting only the second information
In the AM receiving device 22, the multi-value Q transmitted from the transmitting device 1 is used.
The AM modulated signal is received by the second receiving antenna 16 and input to the linear amplifier 9. The linear amplifier 9 amplifies the multi-level QAM modulation signal and outputs it to the QAM demodulator 10. The QAM demodulator 10 demodulates the multi-level QAM modulated signal input from the linear amplifier 9 into an I signal and a Q signal, and outputs the signal to the first parallel / serial converter 11. The first parallel / serial converter 11 converts the I signal and the Q signal input from the QAM demodulator 10 into a multiplexed signal and outputs the multiplexed signal to the second multiplexed signal separator 23. Second multiplex signal separation device 2
Reference numeral 3 demultiplexes the multiplexed signal input from the first parallel / serial converter 11 and outputs only the second information to the terminal 24.

Conventionally, this type of wireless communication carries out time division multiplexing by adding each information to a signal frame before modulation, and performs wireless transmission using a QAM modulation method having high frequency use efficiency. In these systems, all multiplexed signals are modulated by the QAM modulation method regardless of the amount of signal information. Therefore, even if only one piece of information contained in the multiplexed signal is demodulated, Q
A receiver capable of demodulating an AM modulated signal was required. Since the QAM modulation method carries information on the amplitude component of a signal to be transmitted, an amplifier used in a wireless device needs to operate in a sufficiently linear region, and does not require much FM and a linear region that can be used in a nonlinear region. P
There is a disadvantage that power consumption increases as compared with the SK method. In particular, in the case of a receiver used in a disaster prevention wireless system, when a commercial power supply is interrupted due to a disaster or the like, the commercial power supply is often switched to battery operation, and the QAM modulation method uses an FM modulation method due to an increase in power consumption. And the operation time is shorter than that of the PSK modulation method.

[0006]

As described above, the above QA
In the M modulation method, since linear amplification is essential, there is a problem that power consumption increases and a system operation time when a battery is driven is shortened.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a communication system that suppresses power consumption of a receiving device and extends operation time.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a multi-valued first information having a large amount of information and a second information having a small amount of information by using a continuous single symbol clock. QAM (Quadrative Amplifier)
A transmitting apparatus for transmitting a modulated (multi-level) QAM signal, a QAM receiving apparatus including a linear amplifier and a QAM demodulating apparatus for demodulating a multi-level QAM signal to extract the first information and the second information; To extract only the second information, a multi-phase PSK (Phase
-Shift Keying) is a communication method including a non-linear amplifier for demodulating a signal and a PSK receiving device including a PSK demodulating device, wherein the second information is synchronized with a symbol clock at a predetermined cycle timing as multi-level QAM. The first information is arranged at a position on the symbol arrangement of the multi-level QAM and on the symbol arrangement of the multi-phase PSK, and the first information is transmitted at a symbol clock timing other than the cycle of the symbol clock for transmitting the second information. It is characterized in that a modulated signal is generated and modulated so as to be arranged at a position on the arrangement.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a structural explanatory view showing an embodiment of the present invention. In the figure, 1 is a transmitting device, 2 is a multiplex signal generating device (MLT1), 3 is a serial / parallel converter (S / P), 4 is a quadrature modulator (MOD), 5 is a terminal for inputting first information. , 6 are terminals for inputting second information, 7
Is a transmitting antenna, 8 is a first receiving antenna, 9 is a linear amplifier (Lin), 10 is a QAM demodulator (DEM), 11 is a first parallel / serial converter (P / S), and 12 is a first The multiplex signal separation device (MLT2), 13 is the first QA
M receiving device, 14 is a terminal for outputting first information, 15 is a first terminal for outputting second information, 16 is a second receiving antenna, 17 is a non-linear amplifier (Non-Lin), and 18 is PSK. Demodulator (DEM), 19 is a second parallel / serial converter (P / S), 20 is a PSK receiver, 21
Is a second terminal for outputting second information.

That is, the multiplexed signal generator 2 of the transmitter 1 transmits the frame containing the first information having a large amount of information input from the terminal 5 and the second information having a small amount of information input from the terminal 6. The included frames are multiplexed in a time-division manner to generate a multiplexed signal and output to the serial / parallel converter 3. The serial / parallel converter 3 converts the multiplexed signal input from the multiplexed signal generator 2 into 16 QAM
The I signal converted into a modulated wave signal, and one of the orthogonal carriers
The signal is converted into a Q signal converted into a 6QAM modulated wave signal and output to the quadrature modulator 4. At this time, only when transmitting the second information having a small amount of information, the modulated wave (I) is placed on the multi-level QAM symbol arrangement and the multi-phase PSK symbol arrangement.
And Q signal). The quadrature modulator 4 has a serial /
A multi-level QAM modulated signal obtained by multi-level QAM-modulating the I signal and the Q signal input from the parallel converter 3 with a single symbol clock (period: T) is transmitted from the transmission antenna 7.
In this case, the multiplexed frame is transmitted such that the transmission timing of the frame including the second information having a small amount of information is an integer multiple of twice or more the symbol clock cycle (cycle; T × N, N is an integer of 2 or more). When focusing on only the frame including the second information having a small amount of information, the operation is performed such that the multi-phase PSK modulation wave having the period of T × N symbol clock is continuously transmitted. To achieve this behavior,
The frame length is a natural number times the number of bits in one symbol of the multilevel QAM. That is, in a frame including the first information having a large amount of information, a natural number multiple of n bits in the case of 2 ^n- valued QAM, and in a frame including the second information having a small amount of information, ^{m in} the case of the 2m-phase PSK. Bits are redundant bits (n-
m) is added to k bits (= n bits).

On the other hand, the first QAM receiving device 13 for extracting the first information and the second information receives the multi-level QAM modulated signal transmitted from the transmitting device 1 by the first receiving antenna 8, and receives the linear amplifier 9 To enter. The linear amplifier 9 is a multi-value QA
The M-modulated signal is amplified and output to the QAM demodulator 10.
The QAM demodulator 10 demodulates the multilevel QAM modulated signal input from the linear amplifier 9 into an I signal and a Q signal,
To the parallel / serial converter 11. The first parallel / serial converter 11 converts the I signal and Q signal input from the QAM demodulator 10 into a multiplexed signal and outputs the multiplexed signal to the first multiplexed signal separator 12. The first multiplexed signal separation device 12 separates the multiplexed signal input from the first parallel / serial converter 11 and outputs first information to a terminal 14 and outputs second information to a terminal 15.

In the PSK receiving device 20 for extracting only the second information, the multi-phase PSK signal transmitted from the transmitting device 1 is received by the second receiving antenna 16 and the nonlinear amplifier 17 is received.
To enter. The nonlinear amplifier 17 amplifies the multi-phase PSK signal and outputs it to the PSK demodulator 18. PSK demodulator 1
8 demodulates the polyphase PSK signal input from the non-linear amplifier 17 into an I signal and a Q signal, and outputs the I signal and the Q signal to the second parallel / serial converter 19. The second parallel / serial converter 19 outputs only the second information to the terminal 21 using the I signal and the Q signal input from the PSK demodulator 18.

FIGS. 2A and 2B are explanatory diagrams showing the structure of a frame to be multiplexed according to the embodiment of the present invention. FIG. 2A shows a low-order group signal 1 having first information, and FIG. The lower order group signal 2 having information, (C) is a signal of (PS) of 4PSK.
(D) multiplexes the low-order group signal 1 of (A) and the low-order group signal 2 'of (C). (E) shows the multiplexed signal of (D) as one of the reference carriers.
(F) is a Q signal obtained by converting the multiplexed signal of (D) into a 16QAM modulated wave signal of a quadrature carrier, and (G) is an I signal obtained by converting the multiplexed signal of (D) to the I signal of (E). (F) is a symbol clock for determining the timing for sending the Q signal to the modulation device.

FIG. 3 shows a 16QA located on the carrier phase plane of the modulated wave in the frame configuration example shown in FIG.
The symbol point arrangement (rotation target arrangement) of M and the symbol point arrangement (gray arrangement) when 4PSK is assigned, and a bit sequence corresponding to each symbol is attached.

In this communication system, the frame length (number of bits) of the low-order group signal 1 having a large amount of information to be transmitted is 4 bits, and the frame length (number of bits) of the low-order group signal 2 having a small amount of information to be transmitted is 2 bits. First, the number of bits of the low-order group signal 2 is converted from 2 bits to 4 bits, and this is converted to a low-order group signal 2 '. Divide and multiplex. Note that, as an example of conversion from the low-order group signal 2 to the low-order group signal 2 ′, 00 → 1100, 0
1 → 1000, 11 → 0000, 10 → 0100. The multiplexed signal has a modulated wave symbol arrangement of 1 as shown in FIG.
The signal is converted into an I signal and a Q signal to be a rotation target arrangement of 6QAM, and the symbol clocks are CLK1, CLK3,
Low-order group signal 1 at the timing of CLK5 and CLK7
Information, symbol clocks are CLK2, CLK4, CL
The information of the low-order group signal 2 is transmitted at the timing of K6 and CLK8. At this time, although in synchronization with the symbol clock periods t ₁ to impart symbols to the symbol arrangement of QAM, when the period of t ₂ possessed by each symbol point 4
Of the bit information, the lower two bits (second pass) are 00
Placing the information on where the confers symbols so that the symbol arrangement of 4PSK when focusing only on the period of t _2. By this operation, the receiver for receiving the first information or the second information included in the multiplexed signal can be constituted by a linear amplifier and a single 16QAM demodulator, and the second information included in the multiplexed signal can be constituted. In a receiver that demodulates only information (lower-order group signal 2), a nonlinear amplifier and t
It can be configured using a single PSK demodulator that can focus on only _two periods.

Although the example shown in FIG. 2 describes the case where 16QAM and 4PSK are combined, the same can be said for the case where the symbol arrangement of polyphase PSK is assigned to the symbol arrangement of multilevel QAM. . In the example shown in FIG. 2, the frame allocation ratio between the low-order group signal 1 and the low-order group signal 2 is set to 1: 1 (t ₂ = 2 × t ₁ ).
If the period of ₂ is constant, change the ratio (t ₂ = (1+
n) × t ₁ , where n is a natural number.

In the present invention, multi-level QAM modulation is performed in the transmitter regardless of the content of multiplexed information, and only when specific information with a small amount of information is transmitted, the multi-level QAM symbol arrangement and the multi-phase PSK symbol are used. Modulated waves (I and Q signals) are generated and modulated so as to be arranged. A QAM modulated signal transmitted from a transmitter is received as a multi-level QAM signal by one receiver, and a multi-phase PAM signal is received by the other receiver.
Received as SK signal. With this configuration, a communication system having a function of performing one-to-many opposing communication is provided.

According to the present invention, a frame containing first information having a large amount of information and a frame containing second information having a small amount of information are multiplexed in a transmitter in a time-division manner, and these are multiplexed into a single symbol clock ( Multi-level QAM modulation is performed at a period T). When modulating a frame signal including second information having a small amount of information, a modulated wave signal is generated and modulated on a multi-level QAM symbol arrangement and a multi-phase PSK symbol arrangement. At this time, the multiplexed frame is transmitted such that the transmission timing of the frame including the second information having a small amount of information is an integer multiple of twice or more of the symbol clock cycle (cycle; T × N, N is an integer of 2 or more). When focusing on only the frame including the second information having a small amount of information, the operation is performed such that the multi-phase PSK modulation wave having the period of T × N symbol clock is continuously transmitted. In order to realize this operation, the frame length is set to a natural number times the number of bits in one symbol of the multi-level QAM. That is, in a frame including the first information having a large amount of information, a natural number multiple of n bits in the case of 2 ^n- valued QAM, and in a frame including the second information having a small amount of information, ^{m in} the case of the 2m-phase PSK. K bits (= n bits) obtained by adding redundant bits (nm) to bits
And In a receiver that extracts all information, multi-level QAM
And a receiver that extracts only the second information is configured with a receiving system that can demodulate polyphase PSK. With these means, a PSK receiver that can simultaneously transmit the first information and the second information in a single configuration, and that can be configured with low power consumption when extracting only the second information is provided. It can be used.

[0020]

As described above, according to the present invention,
When only one piece of multiplexed information is demodulated, it is possible to use the PSK receiving method with high power supply efficiency, and it is possible to extend the operation time when the battery is driven. If applied to the field of disaster prevention radio, in which loudspeaker broadcasting and text information transmission are performed in one base station device-to-multipoint communication, the base station can transmit loudspeaker broadcasting (16
QAM) and character information (4PSK) with a small amount of information can be multiplex-transmitted, and a receiver (4PSK receiver) that receives only character information can be a battery-powered portable device. Can receive loudspeaker broadcasts and text information during normal operation (16QAM), and in battery operation in the event of a power outage due to a disaster or the like, it is possible to extend the operation time by switching to a PSK receiver that receives only text information and consumes less power. it can.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a frame to be multiplexed according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a symbol point arrangement of 16QAM and 4PSK located on a carrier phase plane of a modulated wave according to the embodiment of the present invention.

FIG. 4 is a configuration explanatory view showing a conventional communication system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmitting apparatus 2 Multiplexed signal generating apparatus 3 Serial / parallel converter 4 Quadrature modulator 5 Terminal for inputting first information 6 Terminal for inputting second information 7 Transmitting antenna 8 First receiving antenna 9 Linear amplifier 10 QAM Demodulator 11 First parallel / serial converter 12 First multiplexed signal separator 13 First QAM receiver 14 Terminal for outputting first information 15 First terminal for outputting second information 16 Second Reception antenna 17 nonlinear amplifier 18 PSK demodulator 19 second parallel / serial converter 20 PSK receiver 21 second terminal for outputting second information 22 second QAM receiver 23 second multiplex signal separator 24 Third terminal for outputting second information

Claims (1)

[Claims] 1. A multi-level QAM (Quadrative Amplifier) by using a single symbol clock that continuously connects first information having a large amount of information and second information having a small amount of information.
a QAM receiving apparatus comprising: a transmitting apparatus that transmits an e-modulated multi-level QAM signal; a QAM receiving apparatus including a linear amplifier and a QAM demodulating apparatus that demodulate the multi-level QAM signal to extract the first information and the second information. , To extract only the second information, a multi-phase PSK (Phas
e-Shift Keying) A communication method including a non-linear amplifier for demodulating a signal and a PSK receiving device including a PSK demodulating device, wherein the second information is synchronized with a symbol clock at a predetermined period as multi-level QAM. Are arranged on the symbol arrangement of the multi-level QAM and on the symbol arrangement of the multi-phase PSK, and the first information is converted to the multi-level QAM at a symbol clock timing other than the cycle of the symbol clock for transmitting the second information. A communication system characterized in that a modulated signal is generated and modulated so as to be arranged at a position on a symbol arrangement.