JP3489570B2 - Modulation system, receiving apparatus thereof, and wireless communication system using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital modulation method used for wireless communication and a wireless communication system using the same.

[0002]

2. Description of the Related Art Conventionally, as a method relating to pilot symbols when performing quasi-coherent detection in a digital mobile radio communication system, a method described in Japanese Patent Laid-Open No. 9-93302 is known. FIG. 26 shows a conventional frame structure of a signal to be transmitted. In FIG.
The frame is composed of N symbols, and there are 2 pilot symbols consisting of known data at the beginning of the frame.
, Followed by (N-2) information symbols, which is repeated for each frame in the transmitted signal.

[0003]

However, the conventional method has a drawback that the data transmission amount is reduced because the pilot symbols are known data.

According to the present invention, a PSK modulation method is periodically inserted into a multi-level modulation method of 8 levels or more, and data is transmitted using PSK modulation symbols, and at the same time, it has a role as a pilot symbol. The purpose is to suppress a decrease in data transmission amount.

[0005]

In order to solve this problem, the present invention inserts a PSK modulation system periodically into a multi-level modulation system of 8 levels or more and makes a difference between symbols of the PSK modulation system. By performing dynamic coding and transmitting data, and at the same time using the pilot symbol for estimating the amount of frequency offset and the amount of amplitude distortion between the transmitter and receiver on the demodulation side,
Performs quasi-synchronous detection.

As a result, since data is transmitted by the PSK modulation method, it is possible to suppress a decrease in data transmission amount as compared with a method in which known data is used as a pilot symbol.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is used for wireless communication, and is a multi-level modulation system which is a first modulation system and a phase modulation which is a second modulation system regularly. (P
SK: Phase Shift Keying) is inserted as a pilot signal , data is added to the signal of the phase modulation method, and the amplitude and phase distortion amounts of the received signal of the multilevel modulation method are obtained using the pilot signal. , The first modulation
The information sequence of the signal points of the system is used as the signal immediately before the second modulation system.
This is a modulation method in which the signal point position is used as a reference . In the PSK modulation method, quasi-synchronization is performed by using data as a pilot symbol for estimating the frequency offset amount and the amplitude distortion amount between the transmitter and receiver at the demodulation side. By performing the detection, there is an effect that it is possible to suppress a decrease in the data transmission amount as compared with a method in which known data is used as a pilot symbol.

[0008]

The invention according to claim 2 is the modulation system according to claim 1 in which differential coding is performed between symbols of the second modulation system, and in the PSK modulation system, data is transmitted at the same time as transmission and reception on the demodulation side. By performing quasi-synchronous detection by using pilot symbols for estimating the amount of frequency offset and amplitude distortion between units, it is possible to suppress the decrease in data transmission amount compared to the method using known data as pilot symbols. It has the effect that

According to a third aspect of the present invention, the multilevel modulation method is a multilevel quadrature amplitude modulation (QAM: Quadrature) of eight or more levels.
Amplitude Modulation) method according to any one of claims 1 to 2 , wherein the PSK modulation method is for transmitting data and at the same time estimating a frequency offset amount and an amplitude distortion amount between a transmitter and a receiver on the demodulation side. By performing the quasi-coherent detection by using the pilot symbol, it is possible to suppress the decrease in the data transmission amount as compared with the method of using the known data as the pilot symbol.

The fourth aspect of the present invention is the modulation system according to the third aspect , wherein the multi-level QAM system with eight or more levels is a 16QAM system, and in the PSK modulation system, data is transmitted at the same time as transmission and reception on the demodulation side. By performing quasi-synchronous detection by using pilot symbols for estimating the amount of frequency offset and amplitude distortion between units, it is possible to suppress the decrease in data transmission amount compared to the method using known data as pilot symbols. It has the effect that

According to a fifth aspect of the present invention, a multi-valued QAM system with eight or more values is a multi-valued QA with eight or more values obtained by rotating a signal point in the in-phase-quadrature plane about the origin by π / 4 radians.
The modulation method according to claim 3, which is the M method, wherein in the PSK modulation method, the data is transmitted, and at the same time, the demodulation side uses a pilot symbol for estimating a frequency offset amount and an amplitude distortion amount between the transmitter and the receiver. By performing the synchronous detection, it is possible to suppress the decrease in the data transmission amount as compared with the method using known data as the pilot symbol.

According to a sixth aspect of the present invention, in the 16QAM system, the signal point is π around the origin on the in-phase-quadrature plane.
/ 4 is a 16QAM scheme is radian rotation claims 4
By the modulation method described, in the PSK modulation method, the quasi-coherent detection is performed by using the pilot symbol for estimating the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver on the demodulation side at the same time as transmitting the data. Compared with the method that uses known data as pilot symbols,
This has an effect of suppressing a decrease in data transmission amount.

In a seventh aspect of the present invention, the PSK modulation method is a quadrature phase shift (QPSK: Quadrature Phase Shise).
7. The modulation method according to claim 1 , wherein the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver at the same time as transmitting the data in the PSK modulation method. By performing the quasi-coherent detection by using the pilot symbol, it is possible to suppress the decrease in the data transmission amount as compared with the method of using the known data as the pilot symbol.

The invention according to claim 8 is the PSK modulation method according to any one of claims 1 to 7 , wherein the PSK modulation method is a PSK modulation method having signal points on an in-phase axis and an orthogonal axis on an in-phase-quadrature plane. In the PSK modulation method, known data is transmitted by performing quasi-synchronous detection by using pilot symbols for transmitting the data and estimating the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver on the demodulation side at the same time. Compared with the method using as a pilot symbol, there is an effect that it is possible to construct a wireless communication system in which a decrease in data transmission amount is suppressed.

[0016] The invention according to claim 9 is the invention according to claims 1 to
8. A wireless communication system using the modulation method according to any one of 8 above, wherein in the PSK modulation method, the demodulation side is used as a pilot symbol for estimating a frequency offset amount and an amplitude distortion amount between a transmitter and a receiver at the same time. As a result, the quasi-coherent detection has the effect of constructing a wireless communication system that suppresses a reduction in the amount of data transmission, as compared with a method that uses known data as pilot symbols.

The invention according to claim 10 is the invention according to claim 1.
9. A receiving device for receiving a signal of the modulation method according to any one of to 8 , wherein a radio unit that divides the received signal into an in-phase component and a quadrature component of a quadrature baseband signal, and a distortion amount of the in-phase component and the quadrature component. And a distortion estimation unit for estimating the signal, and in the PSK modulation method, the demodulation side uses a pilot symbol for estimating the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver at the same time as transmitting the data. By performing the synchronous detection, it is possible to construct a wireless communication system that suppresses a decrease in the amount of data transmission, as compared with a method that uses known data as pilot symbols.

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a conceptual diagram of the configuration of a wireless communication system according to the present embodiment. In FIG. 1, 10 is a transmitter, 11 is a transmission digital signal, 12 is a quadrature baseband modulator, which inputs the transmission digital signal 11 and outputs an in-phase component 13 and a quadrature component 14 of the transmission quadrature baseband signal. , The in-phase component 13 and the quadrature component 14 are converted into a transmission signal 16 by the transmission radio unit 15,
It transmits from the antenna 17. 20 is a receiver, 21
Is an antenna, and 22 is a reception radio unit, which inputs a signal received by the antenna and receives an in-phase component 2 of a reception quadrature baseband signal.
3 and the orthogonal component 24 are output. An amplitude distortion amount estimation unit 25 inputs the in-phase component 23 and the quadrature component 24, estimates the amplitude distortion amount, and outputs an amplitude distortion amount estimation signal 27. 26
Is a frequency offset amount estimation unit, inputs the in-phase component 23 and the quadrature component 24, estimates the frequency offset amount, and outputs the frequency offset amount estimation signal 28. A quasi-synchronous detection unit 29 inputs the in-phase component 23 and the quadrature component 24, the amplitude distortion amount estimation signal 27 and the frequency offset amount estimation signal 28, performs quasi-synchronous detection, and outputs a reception digital signal.

FIG. 2 shows an arrangement of signal points on the in-phase I-quadrature Q plane of an 8-phase PSK modulation system which is an example of a multi-level modulation system with eight or more levels. In FIG. 2, 101 is an 8-phase PSK.
This is the signal point of the modulation method. FIG. 3 shows a binary phase shift keying (BPSK) which is an example of the PSK modulation method.
FIG. 3 shows a signal point arrangement on the in-phase I-quadrature Q plane of the (t Keying) system, and in FIG. 3, 201 is a signal point of the BPSK modulation system. FIG. 4 shows an 8-phase PSK modulation symbol and BP.
It shows an example of the configuration within N symbols of the SK modulation symbol. Then, FIG. 5 shows an example of an information sequence arrangement of signal points of the BPSK modulation method when differential encoding is performed. FIGS. 6A and 6B are examples of the relationship between the signal point of the immediately preceding BPSK modulation symbol and the information sequence of the signal point of the 8-phase PSK modulation method. In FIG. 6, 501 is a signal point of the BPSK modulation method, Reference numeral 502 is a signal point of the 8-phase PSK modulation method.

With reference to FIGS. 1 to 6, in a modulation system in which a PSK modulation system is periodically inserted in a multi-level modulation system of 8 levels or more, differential coding is performed between PSK modulation symbols,
The information sequence of the signal point of the multi-valued modulation method of 8 levels or more is set to P immediately before.
A modulation method in which the signal point position of the SK modulation symbol is used as a reference will be described.

FIG. 2 shows an arrangement of signal points 101 of the 8-phase PSK modulation method on the in-phase I-quadrature Q plane, and the arrangement position of the signal points 101 is represented by (Equation 1). However,
The signal point 101 of the 8-phase PSK modulation method is (I _8PSK ,
Q _8PSK ), where k is an integer and p is a constant.

[0023]

[Equation 1]

FIG. 3 shows the BP in the in-phase I-quadrature Q plane.
The arrangement of the signal points 201 of the SK modulation method is shown, and the arrangement position of the signal points 201 is represented by (Equation 2). However, B
The signal point 201 of the PSK modulation method is represented by (I _BPSK , Q _BPSK ), where k is an integer and r is a constant.

[0025]

[Equation 2]

FIG. 4 shows an 8-phase PSK in N symbols.
It is an example of a configuration of a modulation symbol and a BPSK modulation symbol. At this time, the phase in the in-phase I-quadrature Q plane of the i-th BPSK modulation symbol is φ _i , i + N
If the phase in the in-phase I-quadrature Q plane of the th BPSK modulation symbol is φ _{i + N} , then i + N in the xy plane.
The th phase θ _{i + N} (Equation 3)

[0027]

[Equation 3]

Then, the information sequence can be defined by θ _{i + N} as shown in FIG.

FIG. 6 shows an example of the relationship between the information sequences of the signal point 501 of the immediately preceding BPSK modulation symbol and the signal point 502 of the 8-phase PSK modulation method. i-th BPS
Signal points 501 of K modulation symbols and i + 1 to i + N-1
The information sequence at the signal point 502 of the eighth 8-phase PSK modulation symbol is, as shown in FIG.
The signal point of the K modulation symbol determines the information sequence of the signal point of the 8-phase PSK modulation symbol.

As described above, data is transmitted in the 8-phase PSK modulation system and data is transmitted in the BPSK modulation system, and at the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols, and the quasi-synchronization is performed. Perform detection. Here, the configurations of 8-phase PSK modulation symbols and BPSK modulation symbols in N symbols are not limited to those shown in FIG. Further, although the 8-phase PSK modulation method has been described as an example of the 8-value or higher multi-value modulation method, the 8-value or higher-value multi-value modulation method is not limited to this, and the BPSK modulation method is an example of the PSK modulation method. As described above, the PSK modulation method is not limited to this.

As described above, according to the present embodiment, the PSK modulation system is periodically inserted in the multi-level modulation system of eight or more values, and differential coding is performed between PSK modulation symbols to obtain eight or more values. Of the information sequence of the signal point of the multi-level modulation method of
The PSK modulation method is a modulation method that is arranged with reference to the signal point position of the modulation symbol. In the PSK modulation method, the demodulation side uses the pilot symbol for estimating the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver. Compared to the method of using known data as pilot symbols to estimate the amount of frequency offset and the amount of amplitude distortion between the transmitter and the receiver, quasi-coherent detection can be performed without reducing the data transmission amount.

In the present embodiment, differential coding is performed between PSK modulation symbols, and an information sequence of signal points of a multi-level modulation method of 8 levels or more is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol. Although the method has been described, the same effect can be obtained by inserting PSK modulation symbols that are differentially encoded between PSK modulation symbols.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in data transmission amount is suppressed.

(Embodiment 2) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

FIG. 7 shows a signal point constellation on the in-phase I-quadrature Q plane of a 2 ^{2 m-} value QAM system which is an example of a multi-level QAM system of eight or more values. In FIG. 7, 601 is a 2 ^{2 m-} value QA system.
This is a signal point of the M method. Further, the signal point arrangement on the in-phase I-quadrature Q plane of the BPSK modulation method, which is an example of the PSK modulation method, is the same as that in FIG. 3 of the first embodiment. FIG. 8 shows 1
The signal point arrangement on the in-phase I-quadrature Q plane of the 6QAM system is shown, and in FIG. 8, reference numeral 701 is the signal point of the 16QAM system. FIG. 9 shows an example of the configuration of N symbols of 16QAM symbols and BPSK modulation symbols. An example of the information sequence arrangement of signal points of the BPSK modulation method when differentially encoded is the same as in FIG. 5 of the first embodiment. Figure 10
10A and 10B are examples of the relationship between the signal point of the immediately preceding BPSK modulation symbol and the information sequence of the 16QAM system signal point. In FIG. 10, 901 is the signal point of the BPSK modulation system and 902 is the 16QAM system. It is a signal point.

Using FIG. 1, FIG. 3, FIG. 5, and FIG. 7 to FIG.
In a modulation method in which a modulation method is inserted, differential coding is performed between PSK modulation symbols, and an information sequence of 8-point or higher multi-level QAM method signal points is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol. , Or a modulation method in which a PSK modulation method is periodically inserted in the 16QAM method, differential coding is performed between PSK modulation symbols, and 1
A modulation method for arranging the signal point information sequence of the 6QAM method with the signal point position of the immediately preceding PSK modulation symbol as a reference will be described.

FIG. 7 shows 2 ^{2m in the} in-phase I-quadrature Q plane.
The arrangement of the signal points 601 of the value QAM method is shown, and the arrangement position of the signal points 601 is represented by (Equation 4). However, 2
The signal point 401 of the ^2m- ary QAM system is represented by (I _QAM , Q _QAM ), and m is an integer, (a ₁ , b ₁ ), (a ₂ , b ₂ ), ...
(A _m, b _m) is 1, -1 binary code, r is the constant.

[0038]

[Equation 4]

FIG. 8 illustrates 16 in the in-phase I-quadrature Q plane.
The arrangement of the signal points 701 of the QAM system is shown.
The arrangement position of 701 is represented by (Equation 5). However, 16
The signal point 701 of the QAM system is (I_16QAM, Q_16QAM)
And then (a₁, B₁), (A₂, B ₂) Is a binary mark of 1, -1
No. and s are constants.

[0040]

[Equation 5]

The signal point constellation of the BPSK modulation method is shown in FIG. 3 and is the same as the description of the first embodiment.

FIG. 9 shows 16QAM in N symbols.
3 shows an example of the configuration of symbols and BPSK modulation symbols. At this time, if the phase of the i-th BPSK modulation symbol in the in-phase I-quadrature Q plane is φ _i and the phase of the i + N-th BPSK modulation symbol in the in-phase I-quadrature Q plane is φ _{i + N} , then in the xy plane. If the i + Nth phase θ _{i + N} is (Equation 3), the information sequence can be determined by θ _{i + N} as shown in FIG.

FIG. 10 shows an example of the relationship between the information sequences of the signal point 901 of the immediately preceding BPSK modulation symbol and the signal point 902 of the 16QAM system. i-th BPSK
The information sequence of the signal point 901 of the modulation symbol and the signal point 902 of the 16QAM symbol from i + 1 to i + N−1 is
It is represented by two types of FIG. 10 (a) or FIG. 10 (b).

As described above, data is transmitted in the 16QAM system and data is transmitted in the BPSK modulation system, and at the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols and performs the quasi-coherent detection. Here, the configurations of 16QAM symbols and BPSK modulation symbols in N symbols are not limited to those shown in FIG. Further, the 16QAM system has been described as an example, but the same applies to the 2 ^2m value QAM system, and at this time, the multilevel QAM system of 8 or more values is not limited to the 2 ^2m value QAM system.
Although the BPSK modulation method has been described as an example of the PSK modulation method, the PSK modulation method is not limited to this.

As described above, according to the present embodiment, the PSK modulation system is periodically inserted into the multi-level QAM system with eight or more levels, and the PSK modulation symbols are differentially encoded to obtain 8 levels.
The information sequence of the multi-valued QAM system signal point that is equal to or greater than the value
An information sequence of signal points of the 16QAM method by periodically inserting the PSK modulation method into the modulation method in which the signal point position of the SK modulation symbol is arranged or the 16QAM method, and differentially coding between the PSK modulation symbols. Just before PSK
The PSK modulation method is a modulation method that is arranged with reference to the signal point position of the modulation symbol. In the PSK modulation method, the demodulation side uses the pilot symbol for estimating the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver. Compared to the method of using known data as pilot symbols to estimate the amount of frequency offset and the amount of amplitude distortion between the transmitter and the receiver, quasi-coherent detection can be performed without reducing the data transmission amount.

In the present embodiment, differential coding is performed between PSK modulation symbols, and an information sequence of 8-point or higher multi-level QAM system signal points is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol. The method of arranging the signal sequence of the 16QAM method or the signal sequence of the 16QAM method with reference to the signal point position of the immediately preceding PSK modulation symbol has been described.
A similar effect can be obtained by inserting a PSK modulation symbol that is differentially encoded between modulation symbols.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in the amount of data transmission is suppressed.

(Embodiment 3) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

FIG. 11 shows 8 in the in-phase I-quadrature Q plane.
In-phase I-, which is an example of a multi-valued QAM system with eight or more values obtained by rotating a signal point of the multi-valued QAM system with more than one value by π / 4 radians
The signal point of the 2 ^2m- ary QAM system is π / 4 on the orthogonal Q plane.
In-phase I-quadrature Q of 2 ^2m value QAM system rotated by radian
The signal point arrangement on the plane is shown in FIG.
Reference numeral 01 is a signal point of the 2 ^2m value QAM system. Also, P
In-phase I- of the BPSK modulation method, which is an example of the SK modulation method
The signal point arrangement on the orthogonal Q plane is the same as in FIG. 3 of the first embodiment. FIG. 12 shows 1 in the in-phase I-quadrature Q plane.
16QAM system signal point rotated by π / 4 radian 16
The signal point arrangement on the in-phase I-quadrature Q plane of the QAM system is shown, and in FIG. 12, 1101 is the signal point of the 16QAM system. The configuration of N symbols of the 16QAM symbol and the BPSK modulation symbol is shown in FIG.
Is the same as. An example of the information sequence arrangement of signal points of the BPSK modulation method when differentially encoded is the same as in FIG. 5 of the first embodiment. 13 (a) and 13 (b) show the immediately preceding BPSK.
FIG. 14 is an example of a relationship between a signal point of a modulation symbol and an information sequence of the signal point of the 16QAM system, which is 120 in FIG.
1 is a signal point of the BPSK modulation method, and 1202 is the 16Q
This is an AM system signal point.

1, FIG. 3, FIG. 5, FIG. 9, and FIG. 11 to FIG. 13, in the modulation method in which the PSK modulation method is periodically inserted into the multi-level QAM method of eight or more values, PSK
In the 16QAM system, or a modulation system in which differential coding is performed between modulation symbols, and an information sequence of signal points of the multilevel QAM system of eight or more levels is arranged with the signal point position of the immediately preceding PSK modulation symbol as a reference, Regarding a modulation method in which a PSK modulation method is periodically inserted, differential coding is performed between PSK modulation symbols, and an information sequence of signal points of the 16QAM method is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol. explain.

FIG. 11 shows the front in the in-phase I-quadrature Q plane.
Note 2^2mThe layout of the signal points 1001 of the value QAM method is shown.
Therefore, the arrangement position of the signal point 1001 is represented by (Equation 6).
However, the above 2^2mThe signal point 1001 of the value QAM method is (I
_QAMR, Q_QAMR), (I _QAM, Q_QAM) Is (Equation 4)
It is represented and n is an integer.

[0052]

[Equation 6]

FIG. 12 shows the front in the in-phase I-quadrature Q plane.
The layout of signal points 1101 of the 16QAM system is shown below.
Therefore, the arrangement position of the signal point 1101 is represented by (Equation 7).
However, the signal point 1101 of the 16QAM system is (I
_16QAMR, Q_16QAMR), (I _16QAM, Q_16QAM) Is
It is represented by (Equation 5), and n is an integer.

[0054]

[Equation 7]

The signal point constellation of the BPSK modulation method is shown in FIG. 3 and is the same as the description of the first embodiment.

FIG. 9 shows the 16Q in N symbols.
It shows an example of a structure of an AM symbol and a BPSK modulation symbol. At this time, the phase in the in-phase I-quadrature Q plane of the i-th BPSK modulation symbol is φ _i , i + N
If the phase in the in-phase I-quadrature Q plane of the th BPSK modulation symbol is φ _{i + N} , then i + N in the xy plane.
If the th phase θ _{i + N} is (Equation 3), the information sequence can be determined by θ _{i + N} as shown in FIG.

FIG. 13 shows the signal point 1201 of the immediately preceding BPSK modulation symbol and the signal point 1202 of the 16QAM system.
2 shows an example of the relationship of the information series of. The signal points 1201 and i + 1 to i of the i-th BPSK modulation symbol
+ N-1th signal point 120 of the 16QAM symbol
The information sequence of 2 corresponds to 2 of FIG. 13 (a) or 13 (b).
Expressed in the street.

As described above, the 16QAM system transmits data, and the BPSK modulation system transmits data. At the same time, the demodulation side estimates the frequency offset amount and amplitude distortion amount between the transmitter and the receiver as pilot symbols, and performs quasi-coherent detection. . Here, the configurations of the 16QAM symbols and BPSK modulation symbols in N symbols are not limited to those shown in FIG. Further, the 16QAM system has been described as an example, but the same applies to the 2 ^2m value QAM system, and at this time, the multilevel QAM system of 8 or more values is not limited to the 2 ^2m value QAM system. Although the BPSK modulation method has been described as an example of the PSK modulation method, the PSK modulation method is not limited to this.

As described above, according to the present embodiment, the PSK modulation system is periodically inserted in the multi-level QAM system of eight or more values, and differential coding is performed between PSK modulation symbols, and the A PSK modulation scheme is periodically inserted in the modulation scheme in which an information sequence of signal points of a multi-valued QAM scheme equal to or larger than the value is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol, or the PSK modulation scheme is periodically inserted into the PSK modulation scheme. This is a modulation method in which differential coding is performed between modulation symbols, and the information sequence of the signal points of the 16QAM method is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol. In the PSK modulation method, data is transmitted and demodulation side is performed at the same time. By using the pilot symbols to estimate the amount of frequency offset and amplitude distortion between the transmitter and receiver, the amount of frequency offset and amplitude distortion between the transmitter and receiver can be calculated. Compared to method of the pilot symbol known data to the constant, it is possible to perform quasi-synchronous detection without reducing the amount of data transmission.

In the present embodiment, differential coding is performed between PSK modulation symbols, and the information sequence of the signal point of the multilevel QAM system of eight or more values is arranged with reference to the signal point position of the immediately preceding PSK modulation symbol. Method or 16QA
Although the method of arranging the information sequence of the signal points of the M system with reference to the signal point position of the immediately preceding PSK modulation symbol has been described, the same is true in all cases by inserting the PSK modulation symbol differentially encoded between the PSK modulation symbols. The effect is obtained.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in data transmission amount is suppressed.

(Embodiment 4) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

The signal point arrangement on the in-phase I-quadrature Q plane of the 8-phase PSK modulation system, which is an example of the multi-level modulation system of 8 levels or more, is the same as that of FIG. 2 of the first embodiment. FIG. 14 shows a signal point arrangement of the QPSK modulation method on the in-phase I-quadrature Q plane, and 1301 in FIG. 14 is a signal point of the QPSK modulation method. FIG. 15 shows an 8-phase PSK modulation symbol and Q.
The example of the structure in the N symbol of the PSK modulation symbol is shown. FIG. 16 shows an example of information sequence arrangement of signal points of the QPSK modulation method when differentially encoded. FIG. 17
(A), (b), (c) and (d) are the immediately preceding QPSK
17 is an example of a relationship between a signal point of a modulation symbol and an information sequence of a signal point of an 8-phase PSK modulation method, which is 160 in FIG.
1 is a signal point of the QPSK modulation method, 1602 is an 8-phase PSK
This is the signal point of the modulation method.

8 with reference to FIGS. 1, 2, and 14 to 17.
In a modulation method in which a QPSK modulation method is regularly inserted in a multi-value modulation method of more than a value, differential coding is performed between QPSK modulation symbols, and an information sequence of signal points of a multi-value modulation method of eight or more values is immediately preceding. A modulation method will be described in which the signal points of the QPSK modulation symbols are arranged as a reference.

The signal point arrangement of the 8-phase PSK modulation method is as shown in FIG. 2 and is the same as that of the first embodiment.

FIG. 14 shows Q in the in-phase I-quadrature Q plane.
The arrangement of signal points 1301 of the PSK modulation method is shown,
The arrangement position of the signal point 1301 is represented by (Equation 8). However, the signal point 1301 of the QPSK modulation method is (I _QPSK ,
Q _QPSK ), where k is an integer and u is a constant.

[0067]

[Equation 8]

FIG. 15 shows 8-phase PS in N symbols.
It is an example of a configuration of a K modulation symbol and a QPSK modulation symbol. At this time, the phase in the in-phase I-quadrature Q plane of the i-th QPSK modulation symbol is φ _i , i +
If the phase in the in-phase I-quadrature Q plane of the N-th QPSK modulation symbol is φ _{i + N} , then i + in the xy plane
If the Nth phase θ _{i + N} is (Equation 3), the information sequence can be determined by θ _{i + N} as shown in FIG.

FIG. 17 shows the signal point 1601 of the immediately preceding QPSK modulation symbol and the signal point 1602 of the 8-phase PSK modulation method.
2 shows an example of the relationship of the information series of. The signal point 1601 of the i-th QPSK modulation symbol and i + 1 to i
Signal point 160 of + N-1 th 8-phase PSK modulation symbol
As for the information sequence of No. 2, the information sequence of the signal point of the 8-phase PSK modulation symbol is determined by the signal point of the immediately preceding QPSK modulation symbol, as shown in (a), (b), (c) or (d) of FIG.

As described above, data is transmitted in the 8-phase PSK modulation system and data is transmitted in the QPSK modulation system, and at the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols, and the quasi-synchronization is performed. Perform detection. Here, the configurations of 8-phase PSK modulation symbols and QPSK modulation symbols in N symbols are not limited to those in FIG. Further, although the 8-phase PSK modulation method has been described as an example of the 8-value or higher multi-value modulation method, the 8-value or higher-value multi-value modulation method is not limited to this.

As described above, according to the present embodiment, the QPSK modulation system is periodically inserted in the multi-level modulation system of eight or more levels, and the QPSK modulation symbols are differentially encoded.
The information sequence of the signal point of the multi-valued modulation method with eight or more values
A modulation method in which the signal point position of the PSK modulation symbol is arranged as a reference. In the QPSK modulation method, the demodulation side uses the pilot symbol for estimating the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver at the same time. As a result, quasi-coherent detection can be performed without reducing the data transmission amount, as compared with a system in which known data is used as pilot symbols to estimate the amount of frequency offset and the amount of amplitude distortion between the transmitter and the receiver.

In the present embodiment, differential coding is performed between QPSK modulation symbols, and an information sequence of signal points of a multi-level modulation method of eight or more values is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. Although the method has been described, similar effects can be obtained by inserting differentially encoded QPSK modulation symbols between QPSK modulation symbols.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in the amount of data transmission is suppressed.

(Embodiment 5) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

An example of a multi-valued QAM system with eight or more values is 2
The signal point arrangement on the in-phase I-quadrature Q plane of the ^2m- ary QAM system is the same as that in FIG. 7 of the second embodiment. Also, QPS
The signal point arrangement on the in-phase I-quadrature Q plane of the K modulation method is the same as that in FIG. 14 of the fourth embodiment. The signal point arrangement on the in-phase I-quadrature Q plane of the 16QAM system is the same as that of FIG. 8 of the second embodiment. FIG. 18 shows an example of the configuration of 16 QAM symbols and QPSK modulation symbols in N symbols. An example of the information sequence arrangement of signal points of the QPSK modulation method when differentially encoded is shown in FIG.
It is similar to 6. 19 (a), (b), (c) and (d) show the signal point of the immediately preceding QPSK modulation symbol and 16Q.
19 is an example of the relationship of the information sequence of AM signal points, and in FIG. 19, 1801 is a signal point of the QPSK modulation method, 180
Reference numeral 2 is a signal point of the 16QAM system.

FIG. 1, FIG. 7, FIG. 8, FIG. 14, FIG.
8 and FIG. 19, in a modulation method in which a QPSK modulation method is regularly inserted in a multi-level QAM method of eight or more values, differential coding is performed between QPSK modulation symbols, and multi-value QAM of eight or more values is obtained. QP for the information sequence of the signal point of the system
QPSK is regularly used in the 16QAM method or the modulation method in which the signal point position of the SK modulation symbol is used as a reference.
In the modulation method in which a modulation method is inserted, a description will be given of a modulation method in which differential coding is performed between QPSK modulation symbols and an information sequence of signal points of the 16QAM method is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol.

The signal point constellation of the 2 ^2m- ary QAM system is as shown in FIG. 7, and is the same as the description of the second embodiment. 16
The signal point arrangement of the QAM method is as shown in FIG. 8 and is the same as the description of the second embodiment. The signal point constellation of the QPSK modulation method is as shown in FIG. 14, and is the same as the description of the fourth embodiment.

FIG. 18 shows 16QA in N symbols.
It is an example of a configuration of M symbols and QPSK modulation symbols. At this time, if the phase of the i-th QPSK modulation symbol in the in-phase I-quadrature Q plane is φ _i and the phase of the i + N-th QPSK modulation symbol in the in-phase I-quadrature Q plane is φ _{i + N} , then in the xy plane. If the i + Nth phase θ _{i + N} is (Equation 3), the information sequence can be determined by θ _{i + N} as shown in FIG.

FIG. 19 shows an example of the relationship between the information sequences of the signal point 1801 of the immediately preceding QPSK modulation symbol and the signal point 1802 of the 16QAM system. i th QP
Signal points 1801 of SK modulation symbols and i + 1 to i + N
The information sequence of the signal point 1802 of the -1st 16QAM symbol is 4 in FIG. 19 (a), (b), (c) or (d).
That is, the information sequence of the signal point of the 16QAM symbol is determined by the signal point of the immediately preceding QPSK modulation symbol.

As described above, data is transmitted in the 16QAM system and data is transmitted in the QPSK modulation system, and at the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols and performs the quasi-coherent detection. . Here, the configurations of 16QAM symbols and QPSK modulation symbols in N symbols are not limited to those in FIG. Also, the 16 QAM method has been described as an example, but 2 ^2m
The same applies to the value QAM method. At this time, multi-value QAM with eight or more values is not limited to the 2 ^2m value QAM method.

As described above, according to the present embodiment, a QPSK modulation system is periodically inserted in a multi-level QAM system with eight or more levels, and differential coding is performed between QPSK modulation symbols to obtain eight or more levels. In the modulation method in which the information sequence of the signal point of the multi-valued QAM method is arranged based on the signal point position of the immediately preceding QPSK modulation symbol, or in the 16QAM method, the QPSK modulation method is periodically inserted.
This is a modulation method in which differential coding is performed between K modulation symbols, and an information sequence of signal points of the 16QAM system is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. In the QPSK modulation system, data is transmitted and demodulation side is performed at the same time. By using pilot symbols to estimate the amount of frequency offset and amplitude distortion between transceivers, compared to the method of using known data as pilot symbols to estimate the amount of frequency offset and amplitude distortion between transceivers. The quasi-coherent detection can be performed without reducing the data transmission amount.

In the present embodiment, differential coding is performed between QPSK modulation symbols, and an information sequence of signal points of a multi-level QAM system with eight or more values is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. Although the method of arranging the information sequence of the signal point of the 16QAM method or the method based on the signal point position of the immediately preceding QPSK modulation symbol has been described, in both cases, the QPSK modulation symbol differentially encoded between the QPSK modulation symbols is inserted. The same effect can be obtained.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in data transmission amount is suppressed.

(Embodiment 6) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

The signal point arrangement in the in-phase I-quadrature Q plane of the 8-phase PSK modulation system, which is an example of the multi-level modulation system of eight or more levels, is the same as that in FIG. 2 of the first embodiment. FIG. 20 shows a signal point arrangement of the QPSK modulation method having signal points on the in-phase I axis and the quadrature Q axis on the in-phase I-quadrature Q plane, and in FIG. 20, 1901 is the signal point of the QPSK modulation method. FIG. 15 shows an 8-phase PSK modulation symbol and the QP.
It shows an example of the configuration within N symbols of the SK modulation symbol. An example of the information sequence arrangement of signal points of the QPSK modulation method when differentially encoded is the same as in FIG. 16 of the fourth embodiment. 21 (a), (b), (c) and (d)
Is the signal point of the immediately preceding QPSK modulation symbol and the 8-phase PS
FIG. 21 is an example of the relationship of the information sequence of the signal points of the K modulation method, and in FIG. 21, 2001 is the signal point of the QPSK modulation method, and 2002 is the signal point of the 8-phase PSK modulation method.

With reference to FIGS. 1, 2, 15, 16, 20, and 21, in a modulation system in which the QPSK modulation system is periodically inserted into a multilevel modulation system of eight or more values,
The QPSK modulation symbol is differentially encoded, and an information sequence of signal points of a multi-level modulation method of 8 levels or more is converted to the immediately preceding QPSK.
A modulation method in which the signal point position of the K modulation symbol is used as a reference will be described.

The signal point arrangement of the 8-phase PSK modulation method is as shown in FIG. 2 and is the same as that of the first embodiment.

FIG. 20 shows the front in the in-phase I-quadrature Q plane.
The layout of signal points 1901 of the QPSK modulation system is shown.
Therefore, the arrangement of the signal points 1901 is represented by (Equation 9). Was
However, the signal point 1901 of the QPSK modulation method is (I
_QPSKR, Q_QPSKR), (I _QPSK, Q_QPSK) Is (number
2) and n is an integer.

[0089]

[Equation 9]

FIG. 15 shows 8-phase PS in N symbols.
It is an example of a configuration of a K modulation symbol and the QPSK modulation symbol. At this time, the i-th QPS
Let φ be the phase in the in-phase I-quadrature Q plane of the K modulation symbol.
_i , i + Nth in-phase I- of the QPSK modulation symbol
If the phase in the orthogonal Q plane is φ _{i + N,} and the i + Nth phase θ _{i + N} in the xy plane is (Equation 3),
The information sequence can be defined by θ _{i + N} as shown in FIG.

FIG. 21 shows the signal point 2001 of the immediately preceding QPSK modulation symbol and the signal point 20 of the 8-phase PSK modulation method.
2 shows an example of the relationship of the 02 information series. The i-th signal point 2001 of the QPSK modulation symbol and i +
The information sequences of the signal points 2002 of the 1st to i + N−1th 8-phase PSK modulation symbols are shown in FIGS.
As in (c) or (d), the information point of the signal point of the 8-phase PSK modulation symbol is determined by the signal point of the immediately preceding QPSK modulation symbol.

As described above, the 8-phase PSK modulation system transmits data, and the QPSK modulation system transmits data. At the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols,
Performs quasi-synchronous detection. Here, 8-phase PSK in N symbols
The structure of the modulation symbol and the QPSK modulation symbol is shown in FIG.
It is not limited to 5. Further, although the 8-phase PSK modulation method has been described as an example of the 8-value or higher multi-value modulation method, the 8-value or higher-value multi-value modulation method is not limited to this.

As described above, according to the present embodiment, the QPSK modulation method is periodically inserted in the multi-valued modulation method of eight or more values, and the QPSK modulation symbols are differentially encoded, Is a modulation method in which an information sequence of signal points of a multi-valued modulation method equal to or more than a value is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. In the QPSK modulation method, data is transmitted and at the same time between the transmitter and the receiver on the demodulation side. By using pilot symbols to estimate the amount of frequency offset and amplitude distortion of the data transmission, compared to the method of using known data as pilot symbols to estimate the amount of frequency offset and amplitude distortion between the transmitter and receiver Quasi-synchronous detection can be performed without reducing the amount.

In the present embodiment, differential coding is performed between the QPSK modulation symbols, and the information sequence of the signal point of the multilevel modulation method of eight or more values is based on the signal point position of the immediately preceding QPSK modulation symbol. Although the arrangement method has been described, the same effect can be obtained by inserting differentially encoded QPSK modulation symbols between the QPSK modulation symbols.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in the amount of data transmission is suppressed.

(Embodiment 7) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

2 which is an example of a multi-level QAM system of eight or more levels
The signal point arrangement on the in-phase I-quadrature Q plane of the ^2m- ary QAM system is the same as that in FIG. 7 of the second embodiment. The signal point arrangement of the QPSK modulation method having signal points on the in-phase I axis and the quadrature Q axis on the in-phase I-quadrature Q plane is the same as that in FIG. 20 of the sixth embodiment. The signal point arrangement on the in-phase I-quadrature Q plane of the 16QAM system is the same as that of FIG. 8 of the second embodiment. FIG. 18 shows an example of the structure of 16 QAM symbols and the N symbols of the QPSK modulation symbol.
An example of the information sequence arrangement of signal points of the QPSK modulation method when differentially encoded is the same as in FIG. 16 of the fourth embodiment. 22 (a), (b), (c) and (d) show an example of the relationship between the information sequence of the signal point of the immediately preceding QPSK modulation symbol and the signal point of 16QAM, and in FIG.
Reference numeral 2101 is a signal point of the QPSK modulation method, and 2102 is a signal point of the 16QAM method.

1, FIG. 7, FIG. 8, FIG. 16, FIG. 18, and FIG.
0 and FIG. 22, in a modulation method in which the QPSK modulation method is periodically inserted in an 8-value or higher multi-level QAM method, differential coding is performed between the QPSK modulation symbols, and 8-value or higher-value multi-value QAM methods are used. In the modulation method in which the information sequence of the signal points of the value QAM method is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol, or in the 16QAM method, the QPSK modulation method is periodically inserted, QPSK modulation symbols are differentially encoded between 1
The information sequence of the signal points of the 6QAM system is set to the immediately preceding QPSK.
A modulation method in which the signal point position of the modulation symbol is used as a reference will be described.

The signal point arrangement of the 2 ^2m QAM system is as shown in FIG. 7, and is the same as the description of the second embodiment. 16
The signal point arrangement of the QAM method is as shown in FIG. 8 and is the same as the description of the second embodiment. The signal point arrangement of the QPSK modulation method is as shown in FIG. 20, and is the same as the description of the sixth embodiment.

FIG. 18 shows 16QA in N symbols.
It is an example of a configuration of M symbols and the QPSK modulation symbol. At this time, the phase in the in-phase I-quadrature Q plane of the i-th QPSK modulation symbol is φ _i ,
If the phase of the i + N-th QPSK modulation symbol in the in-phase I-quadrature Q plane is φ _{i + N} , then the i + N-th phase in the xy plane is θ _{i + N} (Equation 3), then θ
_The information sequence can be defined by _{i + N} as shown in FIG.

FIG. 22 shows the signal point 2101 of the immediately preceding QPSK modulation symbol and the signal point 2102 of the 16QAM system.
2 shows an example of the relationship of the information series of. The signal point 2101 of the ith QPSK modulation symbol and the signal point 210 of the i + 1 to i + N−1 16QAM symbols
In the information sequence of No. 2, the information sequence of the signal point of the 16QAM symbol is determined by the signal point of the immediately preceding QPSK modulation symbol as shown in FIG. 22 (a), (b), (c) or (d).

As described above, the 16QAM system transmits data, and the QPSK modulation system transmits data. At the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols, and the quasi-coherent detection is performed. To do. Here, the structure of the 16QAM symbols in the N symbols and the QPSK modulation symbols is not limited to that shown in FIG. Further, the same applies to have been described 16QAM scheme Example 2 ^2m-QAM scheme, multilevel QAM of 8 or more values at this time are not limited to 2 ^2m-QAM scheme.

As described above, according to the present embodiment, the QPSK modulation system is periodically inserted into the multi-level QAM system with eight or more levels, and differential coding is performed between the QPSK modulation symbols. A modulation method in which an information sequence of signal points of a multi-valued QAM method of values or more is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol, or 16QAM method, the QPSK modulation method is periodically inserted, The QP
The QP modulation symbol is differentially coded, and the information sequence of the signal points of the 16QAM system is arranged based on the signal point position of the immediately preceding QPSK modulation symbol.
In the K modulation method, the amount of frequency offset and the amount of amplitude distortion between the transmitter and the receiver are estimated by using pilot symbols for transmitting the data and simultaneously estimating the amount of the frequency offset and the amount of the amplitude distortion between the transmitter and the receiver on the demodulation side. Therefore, quasi-coherent detection can be performed without lowering the data transmission amount, as compared with the method using known data as pilot symbols.

In the present embodiment, differential coding is performed between the QPSK modulation symbols, and an information sequence of signal points of a multi-level QAM system with eight or more values is based on the signal point position of the immediately preceding QPSK modulation symbol. Arrangement method, or 16Q
Although the method of arranging the information sequence of the signal points of the AM system with the signal point position of the immediately preceding QPSK modulation symbol as a reference has been described, in both cases, if the QPSK modulation symbol differentially encoded between the QPSK modulation symbols is inserted. The same effect can be obtained.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in the amount of data transmission is suppressed.

(Embodiment 8) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

22 ^{m on the} in-phase I-quadrature Q plane which is an example of the multi-valued QAM system of 8 or more values obtained by rotating the signal points of the multi-level QAM system of 8 or more values on the in-phase I-quadrature Q plane by π / 4 radian rotation. The signal point arrangement on the in-phase I-quadrature Q plane of the 2 ^2m value QAM method in which the signal points of the value QAM method are rotated by π / 4 radians is the same as that in FIG. 11 of the third embodiment.
The signal point arrangement of the QPSK modulation method on the in-phase I-quadrature Q plane is the same as that of FIG. 14 of the fourth embodiment. In-phase I-
The arrangement of signal points on the in-phase I-quadrature Q plane of the 16QAM scheme in which the signal points of the 16QAM scheme are rotated by π / 4 radians on the quadrature Q plane is the same as in FIG. 12 of the third embodiment. FIG. 18 shows an example of the structure of the 16QAM symbols and the QPSK modulation symbols in N symbols.
An example of the information sequence arrangement of signal points of the QPSK modulation method when differentially encoded is the same as in FIG. 16 of the fourth embodiment.
23 (a), (b), (c) and (d) show the immediately preceding Q.
23 is an example of the relationship between the information sequence of the signal point of the PSK modulation symbol and the signal point of the 16QAM, which is 22 in FIG.
01 is a signal point of the QPSK modulation system, 2202 is the 16
This is a signal point of the QAM system.

FIG. 1, FIG. 11, FIG. 12, FIG. 14, FIG.
With reference to FIGS. 18 and 23, in a modulation method in which a QPSK modulation method is periodically inserted in the multi-valued QAM method having eight or more values, differential coding is performed between QPSK modulation symbols, and the QPSK modulation symbols having eight or more values are used. A modulation method in which an information sequence of signal points of a multilevel QAM method is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol, or in the 16QAM method,
In the modulation method in which the QPSK modulation method is periodically inserted, differential coding is performed between QPSK modulation symbols, and
A modulation method will be described in which a signal point information sequence of the 6QAM method is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol.

The signal point arrangement of the 2 ^2m- ary QAM system is shown in FIG.
As described in the first embodiment, the description is the same as that of the third embodiment. The signal point arrangement of the 16QAM system is as shown in FIG. 12, and is the same as the description of the third embodiment. QPSK
The signal point arrangement of the modulation method is as shown in FIG. 14, and is the same as the description of the fourth embodiment.

FIG. 18 shows the 16 symbols in N symbols.
It is an example of a configuration of a QAM symbol and a QPSK modulation symbol. At this time, the phase in the in-phase I-quadrature Q plane of the i-th QPSK modulation symbol is φ _i , i +
If the phase in the in-phase I-quadrature Q plane of the N-th QPSK modulation symbol is φ _{i + N} , then i + in the xy plane
If the Nth phase θ _{i + N} is (Equation 3), the information sequence can be determined by θ _{i + N} as shown in FIG.

FIG. 23 shows the signal point 2201 of the immediately preceding QPSK modulation symbol and the signal point 2202 of the 16QAM system.
2 shows an example of the relationship of the information series of. Signal points 2201 and i + 1 to i of the i-th QPSK modulation symbol
+ N-1th signal point 220 of the 16QAM symbol
In the information sequence of No. 2, the information sequence of the signal point of the 16QAM symbol is determined by the signal point of the immediately preceding QPSK modulation symbol as shown in FIG. 23 (a), (b), (c) or (d).

As described above, the 16QAM system transmits data, and the QPSK modulation system transmits data. At the same time, the demodulation side estimates the frequency offset amount and the amplitude distortion amount between the transmitter and the receiver as pilot symbols and performs the quasi-synchronous detection. To do. Here, the 16 QAM in N symbols
The configuration of symbols and QPSK modulation symbols is not limited to that shown in FIG. Further, the 16QAM system has been described as an example, but the same applies to the 2 ^2m value QAM system, and at this time, the multilevel QAM of 8 or more values is not limited to the 2 ^2m value QAM system.

As described above, according to the present embodiment, the QPSK modulation system is periodically inserted in the multi-level QAM system of eight or more values, and differential coding is performed between QPSK modulation symbols. QPSK modulation method by periodically inserting a QPSK modulation method into the 16QAM method, or a modulation method in which an information sequence of signal points of a multi-valued QAM method equal to or more than a value is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. This is a modulation system in which differential coding is performed between the modulation symbols, and the information sequence of the signal points of the 16QAM system is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. In the QPSK modulation system, data is transmitted and demodulation side is performed at the same time. By using pilot symbols to estimate the amount of frequency offset and the amount of amplitude distortion between the transmitter and receiver, Compared to method of the pilot symbol known data to estimate the amplitude distortion amount, it is possible to perform quasi-synchronous detection without reducing the amount of data transmission.

In the present embodiment, differential coding is performed between QPSK modulation symbols, and the information sequence of the signal point of the multi-valued QAM system with eight or more values is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. Method, or 16Q above
The method of arranging the information sequence of the AM signal point on the basis of the signal point position of the immediately preceding QPSK modulation symbol has been described.
QP that is differentially encoded between QPSK modulation symbols
The same effect can be obtained by inserting the SK modulation symbol.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in the amount of data transmission is suppressed.

(Embodiment 9) The configuration of the radio communication system in the present embodiment is similar to that shown in FIG. 1 in the first embodiment.

22 ^{m in the} in-phase I-quadrature Q plane which is an example of the multi-valued QAM system of eight or more values obtained by rotating the signal points of the multi-valued QAM system of eight or more values in the in-phase I-quadrature Q plane by π / 4 radian rotation. The signal point arrangement on the in-phase I-quadrature Q plane of the 2 ^2m value QAM method in which the signal points of the value QAM method are rotated by π / 4 radians is the same as that in FIG. 11 of the third embodiment.
The signal point arrangement of the QPSK modulation method having signal points on the in-phase I axis and the quadrature Q axis on the in-phase I-quadrature Q plane is the same as that in FIG. 20 of the sixth embodiment. The signal point arrangement on the in-phase I-quadrature Q plane of the 16QAM system, which is obtained by rotating the signal points of the 16QAM system on the in-phase I-quadrature Q plane by π / 4 radians, is the same as that in FIG. 12 of the third embodiment. FIG.
Shows an example of the configuration within the N symbols of the 16QAM symbol and the QPSK modulation symbol. An example of the information sequence arrangement of signal points of the QPSK modulation method when differentially encoded is the same as in FIG. 16 of the fourth embodiment. Figure 2
4 (a), (b), (c) and (d) are the immediately preceding Q
FIG. 25 is an example of a relationship between an information sequence of a signal point of a PSK modulation symbol and an information sequence of the 16QAM signal, and in FIG.
Reference numeral 01 is a signal point of the QPSK modulation method, and 2302 is a signal point of the 16QAM method.

FIG. 1, FIG. 11, FIG. 12, FIG. 16, FIG.
20 and 24, in a modulation method in which the QPSK modulation method is periodically inserted in the multi-valued QAM method of eight or more values, differential coding is performed between the QPSK modulation symbols, and A modulation method in which the information sequence of the signal points of the multi-level QAM method described above is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol, or a modulation method of periodically inserting the QPSK modulation method into the 16QAM method. In the system, a description will be given of a modulation system in which differential coding is performed between the QPSK modulation symbols and the information sequence of the signal points of the 16QAM system is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol.

The signal point arrangement of the 2 ^2m- ary QAM system is shown in FIG.
As described in the first embodiment, the description is the same as that of the third embodiment. The signal point arrangement of the 16QAM system is as shown in FIG. 12, and is the same as the description of the third embodiment. The QP
The signal point arrangement of the SK modulation method is as shown in FIG.
This is similar to the description of the sixth embodiment.

FIG. 18 shows the 16 symbols in N symbols.
It is an example of a configuration of a QAM symbol and the QPSK modulation symbol. At this time, the i-th QPS
Let φ be the phase in the in-phase I-quadrature Q plane of the K modulation symbol.
_i , i + Nth in-phase I- of the QPSK modulation symbol
If the phase in the orthogonal Q plane is φ _{i + N,} and the i + Nth phase θ _{i + N} in the xy plane is (Equation 3),
The information sequence can be defined by θ _{i + N} as shown in FIG.

FIG. 24 shows the signal point 2301 of the immediately preceding QPSK modulation symbol and the signal point 23 of the 16QAM system.
2 shows an example of the relationship of the 02 information series. The i-th signal point 2301 of the QPSK modulation symbol and i +
The information sequence of the signal point 2302 of the 16th QAM symbol from the 1st to the (i + N-1) th is shown in FIGS.
As in (c) or (d), the information point of the signal point of the 16QAM symbol is determined by the signal point of the immediately preceding QPSK modulation symbol.

As described above, in the 16QAM system, the data
Data is transmitted, and data is transmitted in the QPSK modulation method.
At the same time, the demodulation side transmits and receives as pilot symbols.
Estimate the amount of frequency offset and amplitude distortion between machines,
Performs quasi-synchronous detection. Here, the 16Q in N symbols
The structure of the AM symbol and the QPSK modulation symbol is shown in FIG.
It is not limited to eight. In addition, the 16QAM method
As explained in the example, the above 2 ^2mThe same applies to the value QAM method
Then, at this time, the multi-valued QAM of 8 or more is 2 ^2mValue Q
It is not limited to the AM method.

As described above, according to the present embodiment, the QPS is periodically included in the multi-valued QAM system with eight or more values.
Modulation in which a K modulation method is inserted, differential coding is performed between the QPSK modulation symbols, and an information sequence of signal points of the multilevel QAM method of eight or more values is arranged with reference to the signal point position of the immediately preceding QPSK modulation symbol. Method, or 16QA above
The QPSK modulation system is periodically inserted into the M system, differential coding is performed between the QPSK modulation symbols, and an information sequence of signal points of the 16QAM system is immediately preceding the QP.
The QPSK modulation method is a modulation method in which the signal point position of the SK modulation symbol is arranged as a reference, and in the QPSK modulation method, a demodulation side is used as a pilot symbol for estimating a frequency offset amount and an amplitude distortion amount between a transmitter and a receiver. As a result, it is possible to perform quasi-synchronous detection without reducing the data transmission amount, as compared with a system in which known data is used as a pilot symbol in order to estimate the amount of frequency offset and the amount of amplitude distortion between the transmitter and the receiver.

In the present embodiment, differential coding is performed between the QPSK modulation symbols, and the multi-level QA of eight or more values is generated.
A method of arranging the signal point information sequence of the M method with reference to the signal point position of the immediately preceding QPSK modulation symbol, or the information sequence of the signal point of the 16QAM method immediately before the QP
Although the method of arranging based on the signal point position of the SK modulation symbol has been described, the same effect can be obtained by inserting a QPSK modulation symbol that is differentially encoded between the QPSK modulation symbols.

Further, by using such a modulation method, it is possible to construct a communication system in which a decrease in the amount of data transmission is suppressed.

[0126]

EXAMPLE Next, an example in which the present invention is specifically simulated will be described.

In the present embodiment, the 16QAM system is selected as an example of the multilevel QAM system, and the pilot symbol insertion method is compared and examined between the conventional symbol insertion system and the QPSK modulation symbol insertion system according to the present invention. The results are shown. At that time, the known or QPSK modulation symbol length was set to 1 and the data symbol length was set to n.

The conventional symbol insertion method is a method in which one signal point of the maximum signal point amplitude of 16QAM is used as a pilot symbol, and 16QAM is quasi-coherently detected on the receiving side.

The QPSK modulation symbol insertion method according to the present invention is a method in which data is transmitted at the same time when the QPSK modulation symbol is used as a pilot symbol, and 16QAM mapping depends on the immediately preceding QPSK modulation symbol.
Also, QPSK modulation symbols are differentially encoded. On the receiving side, 16QAM is quasi-coherently detected and QPSK is delayedly detected.

FIG. 25 shows the bit error rate (BER) at the noise power density (N0) with respect to the signal energy (Eb) per bit in the modulation method according to the present embodiment.
o) shows a characteristic diagram, and in the above method, n = 1, 7,
The respective characteristics when 15 are shown. From Figure 25,
Known conventional symbol insertion scheme and QPSK of the present invention
Comparing the case where the data symbol lengths of the modulation symbol insertion method are equal, the QPSK modulation symbol insertion method is
It can be seen that the data transmission efficiency is excellent and the BER characteristics are excellent because the data is transmitted using the SK modulation symbol.

[0131]

As described above, according to the present invention, the PSK modulation system is periodically inserted in the multi-level modulation system of 8 levels or more, and the differential coding is performed between the symbols of the PSK modulation system. Thus, known data is used as a pilot symbol by performing quasi-synchronous detection as a pilot symbol for estimating a frequency offset amount and an amplitude distortion amount between a transmitter and a receiver on the demodulation side while transmitting data in the PSK modulation method. Compared with the method, the advantageous effect that the reduction of the data transmission amount can be suppressed can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a signal point arrangement diagram of an 8-phase PSK modulation method according to an embodiment of the present invention.

FIG. 3 is a signal point arrangement diagram of a BPSK modulation method according to an embodiment of the present invention.

FIG. 4 is a diagram showing a frame structure of a signal according to an embodiment of the present invention.

FIG. 5 is a diagram showing an example of a relationship between a signal point and an information sequence of a BPSK modulation method on an xy plane when differential encoding is performed according to an embodiment of the present invention.

FIG. 6 is a diagram showing an example of a relationship between signal points of a BPSK modulation method, signal points of an 8-phase PSK modulation method, and an information sequence according to an embodiment of the present invention.

FIG. 7 is a signal point constellation diagram of a 2 ^{2 m-} ary QAM system according to an embodiment of the present invention.

FIG. 8 is a signal point arrangement diagram of a 16QAM system according to an embodiment of the present invention.

FIG. 9 is a diagram showing a frame structure of a signal according to an embodiment of the present invention.

FIG. 10 is a diagram showing an example of a relationship between signal points of a BPSK modulation method, signal points of a 16QAM method, and an information sequence according to an embodiment of the present invention.

FIG. 11 is a signal point constellation diagram of a 2 ^{2 m-} ary QAM system according to an embodiment of the present invention.

FIG. 12 is a signal point arrangement diagram of a 16QAM system according to an embodiment of the present invention.

FIG. 13 is a diagram showing an example of a relationship between signal points of a BPSK modulation method, signal points of a 16QAM method, and an information sequence according to an embodiment of the present invention.

FIG. 14 is a signal point arrangement diagram of a QPSK modulation method according to an embodiment of the present invention.

FIG. 15 is a diagram showing an example of configurations of 8-phase PSK modulation symbols and QPSK modulation symbols in N symbols according to an embodiment of the present invention.

FIG. 16 is a diagram showing an example of a relationship between a signal point and an information sequence of a QPSK modulation method on an xy plane when differential encoding is performed according to an embodiment of the present invention.

FIG. 17 is a diagram showing an example of a relationship between a signal point of a QPSK modulation method, a signal point of an 8-phase PSK modulation method, and an information sequence according to an embodiment of the present invention.

FIG. 18 is a diagram showing an example of a configuration of 16QAM symbols and QPSK modulation symbols in N symbols according to an embodiment of the present invention.

FIG. 19 is a diagram showing an example of the relationship between the signal points of the QPSK modulation method, the signal points of the 16QAM method, and the information sequence according to the embodiment of the present invention.

FIG. 20 is a signal point arrangement diagram of a QPSK modulation method according to an embodiment of the present invention.

FIG. 21 is a diagram showing an example of a relationship between a signal point of a QPSK modulation method, a signal point of an 8-phase PSK modulation method, and an information sequence according to an embodiment of the present invention.

FIG. 22 is a diagram showing an example of a relationship between signal points of a QPSK modulation method and signal points of a 16QAM method and an information sequence according to an embodiment of the present invention.

FIG. 23 is a diagram showing an example of a relationship between signal points of a QPSK modulation method and signal points of a 16QAM method and an information sequence according to an embodiment of the present invention.

FIG. 24 is a diagram showing an example of a relationship between signal points of a QPSK modulation method and signal points of a 16QAM method and an information sequence according to an embodiment of the present invention.

FIG. 25 is a diagram showing bit error rate characteristics in noise power density with respect to signal energy per bit in the modulation method according to the embodiment of the present invention.

FIG. 26 is a diagram showing a frame structure of a conventional transmitted signal.

[Explanation of symbols]

11 Transmit Digital Signal 12 Quadrature Baseband Modulator 13 Transmit Quadrature Baseband Signal In-phase Component 14 Transmit Quadrature Baseband Signal Quadrature Component 15 Transmit Radio Unit 16 Transmit Signal 17, 21 Antenna 22 Receive Radio Unit 23 Receive Quadrature Base Hand Signal In-phase Component 24 Reception quadrature baseband signal quadrature component 25 Amplitude distortion amount estimation unit 26 Frequency offset amount estimation unit 27 Amplitude distortion amount estimation signal 28 Frequency offset amount estimation signal 29 Quasi-synchronous detection unit 30 Reception digital signal 101, 502, 1602, 1801, 2002 8 Signal point 201, 501, 901, 1201 of phase PSK modulation method Signal point 602 of BPSK modulation method Signal point 701, 902, 1802, 2102 16QAM method signal point 1002 of ^2m- ary QAM method 2 1 in in-phase I-quadrature Q plane of ^2m-QAM system Signal points of 16QAM scheme and signal points of 16QAM scheme was [pi / 4 radians rotating the signal point 1101,1202,2202,2302 phase I- quadrature Q plane 2 ^2m-QAM scheme the issue point was [pi / 4 radians rotation 1301, 1601, 2201 QPSK modulation method signal points 1901, 2001, 2101, 2301 QPSK modulation method signal points having signal points on the in-phase I axis and the quadrature Q axis in the in-phase I-quadrature Q plane

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Moruichi Sagawa 3-10-1 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Matsushita Giken Co., Ltd. (56) Reference JP-A-8-265293 (JP, A) JP 7-297862 (JP, A) JP 7-46216 (JP, A) JP 2000-82978 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 27 / 34 H04L 27/18

Claims (10)

(57) [Claims] 1. A multi-level modulation method, which is a first modulation method, used for wireless communication, and a phase modulation (PSK: Phase Shift Keying) method, which is a second modulation method, is regularly inserted as a pilot signal. , Data in the signal of the phase modulation method
With the addition of, determine the amount of strain amplitude and phase of the received signal of the multi-level modulation scheme using the pilot signal,
The information sequence of the signal points of the first modulation method is used as the second
A modulation method in which the signal point position immediately before the modulation method is used as a reference . 2. The modulation system according to claim 1 , wherein differential encoding is performed between symbols of the second modulation system. 3. A multi-level modulation system is a multi-level quadrature amplitude modulation (QAM) having eight or more levels.
3. The modulation system according to claim 1, which is a system. 4. A multi-valued QAM system with eight or more values is 16QA.
The modulation system according to claim 3, which is an M system. 5. 8 or more values QAM scheme, phase signal points - modulation according to claim 3 wherein the origin is a multivalued QAM scheme than 8 values obtained by [pi / 4 radians rotates about a in the orthogonal planes method. 6. The 16QAM system rotates a signal point in the in-phase-quadrature plane by π / 4 radian about the origin 1
The modulation system according to claim 4, which is a 6QAM system. 7. The PSK modulation method is quadrature phase modulation (QP).
SK: according to a Quadrature Phase ShiftKeying) method
7. The modulation method according to any one of items 1 to 6 . 8. PSK modulation scheme, phase - modulation method according to any one of claims 1 to 7 is a PSK modulation scheme with a signal point the in-phase axis and on the orthogonal axes on the orthogonal plane. 9. A wireless communication system using the modulation method according to claim 1 . 10. A receiving device for receiving a signal of the modulation system according to claim 1 , a radio unit for dividing the received signal into an in-phase component and an orthogonal component of a quadrature baseband signal, and the in-phase component. And a distortion estimation unit that estimates the distortion amount of the orthogonal component.