CN1810003A - Modulation method, modulation apparatus, demodulation apparatus, and radio communication system - Google Patents

Abstract

The 1st and the 2nd quadrature modulator (109,110) use the cosine wave with the frequency of an odd multiple of the fundamental frequency of the Nyquist signal as a carrier wave, and give the delay difference of 2/4 period of each symbol period The Nyquist signal is quadrature modulated. The third quadrature modulator (113) quadrature-modulates the modulated signal obtained by the first quadrature modulator (109) and the modulated signal obtained by the second quadrature modulator (110) using a predetermined carrier. Therefore, it is possible to obtain a modulated signal in which four Nyquist signals are arranged within one symbol period T without interfering with each other.

Description

Modulation method, modulation device, demodulation device and wireless communication system

technical field

The invention relates to a modulation method for improving frequency utilization efficiency, a modulation device, a demodulation device and a wireless communication system.

technical background

In recent years, due to the popularization of information processing technology and the rapid development of a society called IT (Information Technology, Information Technology), people have aroused the demand for and expanded attention to information communication. Needless to say, between society and society, even the communication facilities between individuals and society are eager to achieve high-speed and wireless. Faced with the ever-increasing demand for such mobile communications, it will also cause the depletion of abundant frequency resources.

Now, in order to solve this problem, a kind of spatial multi-layer communication in natural space called MIMO (Multi Input Multi Output) is being developed. However, in the development of communication utilizing the rapidly changing transmission environment, a large amount of signal processing is performed not only in base stations but also in personal terminal devices, which leads to increased power consumption and thicker devices. and increased costs. Therefore, as a fundamental solution, it is urgent to improve the modulation efficiency in the fundamental frequency band.

The modulation method of today's mobile communication is based on quadrature phase modulation called digital communication, and it is the modulation method that can obtain the highest frequency utilization efficiency today. At the pinnacle of this is quadrature amplitude modulation (QAM). When using this modulation method to communicate in a mobile environment, if it is in multi-path fading (Multi Pass Fading) accompanied by high-speed changes, the maximum is 16QAM, and the peak is 4bit (bit)/sec (second)/2Hz (Hz) , that is, the peak is 2bit/sec/Hz.

Development studies are underway to ensure maximum independence and further frequency utilization efficiency by using multiple transmission paths with multiple antennas. For example: if vertically polarized waves and horizontally polarized waves are used, various information can be transmitted on the same frequency. If 16QAM is used respectively, the theoretically maximum frequency utilization efficiency can be 4bit/sec/Hz. However, in reflected waves and mobile environments, in order to perform signal processing on the receiving side so that the orthogonality (independence) of vertically polarized waves and horizontally polarized waves is completely effective, it is necessary to cost more than twice the current equipment.

Similarly, research on using N antennas to pursue an N-times transmission speed is also underway. However, it is very difficult to fully ensure the independence of the transmission paths of the N antennas, which needless to say.

Therefore, instead of exploiting the ever-changing transport environment, the prerequisite is to improve the modulation efficiency in the fundamental frequency band.

Today, the technical basis for improving frequency utilization efficiency is the Nyquist theory, that is, the so-called independent signal wave with high orthogonality with adjacent signal waves (that is, low interference with adjacent signal symbols) Utilization techniques and reduction techniques for inter-symbol interference between adjacent signal waves known as partial acknowledgments or wavelets. An example of such a technique is described in Japanese Patent Publication No. 1988-92143.

The most representative example of the Nyquist theory is represented by sin(x)/x, and the function representing this signal is called the sinc function. The sinc function is a solitary wave, and at the same time forms a zero-crossing at the signal points of adjacent signal waves, so they do not interfere with each other.

In conventional communications, x of sin(x) is used as a time axis variable for phase modulation (PSK) and quadrature amplitude modulation (QAM), and for frequency axis variable is orthogonal frequency division multiplexing communication (OFDM). The time axis and the frequency axis are physically orthogonal, so one of them can be modulated once, and the other can be modulated twice, for example, they can be used as 16QAM-OFDM. This modulation method can maintain a high frequency utilization efficiency and ensure mobile communication capabilities, etc., and obtain a high degree of communication effect.

Here, conventional digital modulation techniques will be described in detail. One of the main purposes of digital modulation is to achieve high frequency utilization efficiency. This technology is called a frequency band limitation technology, that is, a technology that can achieve as high an information transmission as possible within a given frequency bandwidth. In analog transmission, the amount of information itself is modulated, so not only is it redundant, but there is little room for compression and high-efficiency modulation.

The most representative method of digitally modulated frequency band limitation is the method of using the Nyquist filter. The method of using the Nyquist filter is a technique of inserting high-density symbols in order to reduce interference between signals (symbols) on the time axis by giving Nyquist characteristics to symbols.

In order to prevent mutual interference between signals, zero crossing must be realized in each symbol interval period. Call this the Nyquist 1st benchmark. A filter that satisfies this requirement is called a Nyquist filter. A representative example of implementing such a Nyquist filter is the sinc function. The sinc function h(t) when the symbol period is taken as T is expressed by the following arithmetic.

h(t)=sin(πt/T)/(πt/T)...(1)

When establishing this Nyquist filter with a digital filter, the baseband input signal (symbol) must be input through 4 times oversampling.

Here, when the frequency band is limited by the Nyquist filter, the degree of the rolloff (RollOff) rate is determined each time. The value range of the roll-off rate is from 0 to 1. For example, when the roll-off rate is 0.5, the required bandwidth is 1.5 times the transmission speed. Therefore, in order to improve the frequency utilization efficiency, it is best to set the roll-off rate as 0.

FIG. 1 is a schematic diagram of conventional digital quadrature modulation (QPSK). Since the I-axis signal is carried on a cosine carrier, the signal point, that is, the apex of the Nyquist wave, is placed at phase zero. Since the Q-axis signal is carried on a sine carrier, the signal point, that is, the apex of the Quest wave is arranged at the phase π/2. Regarding the I-axis signal, when the information signal is "1", if convex polarity is adopted, it is arranged at the position of the waveform shown as the I-axis signal (+1) in FIG. 1 . When the information signal is "0" or "-1", a convex arrangement is formed below, so it is arranged at the waveform position shown as the I-axis signal (-1) in FIG. 1 .

Similarly, regarding the Q-axis signal, when the information signal is "1", if a convex polarity is used at the top, it is arranged at the waveform position shown as the Q-axis signal (+1) in FIG. 1 . When the information signal is "0" or "-1", a convex arrangement is formed below, and thus arranged at the waveform position shown as the Q-axis signal (-1) in FIG. 1 .

In the conventional method, the Nyquist waveform completely forms one waveform within the range of the symbol period T, which is due to the Nyquist of the NRZ (non-return-to-zero, non-return-to-zero) signal Signaling reasons. At the edge of the Nyquist wave, as shown in Figure 1, the position of the phase π becomes NULL (blank) when the I-axis signal (+1), however, as the potential should not become blank (Null), that is, zero potential. Therefore, adjacent symbols cannot be arranged at π positions like OFDM.

This state is shown in Figure 2. Figure 2 only focuses on the quadrature modulated I-axis signal. From the Nyquist theory, symbols should be configurable in each phase interval π. However, the blank point of the Nyquist wave becomes "-1" instead of zero. Therefore, there is complete interference with the Nyquist wave of the subsequent adjacent symbols, and the composite value becomes zero, that is, it is impossible to arrange the symbols for the π phase as seen in the Nyquis theory.

The above-mentioned content is the present situation of the conventional digital modulation method, and it is also the reason that hinders the improvement of frequency utilization efficiency.

As described above, conventionally proposed modulation schemes are generally constructed on the I-Q plane. This plane is two-dimensional. Therefore, basically, unless multivalued is performed, information that can be transmitted in one symbol period is 2 bits. Nowadays, in the high-speed mobile environment, 16QAM is actually the best modulation method for frequency utilization efficiency. However, under the condition of limited frequency resources, in order to transmit more information, it is necessary to implement a modulation method with better frequency utilization efficiency.

Contents of the invention

An object of the present invention is to provide a modulation method, a modulation device, a demodulation device, and a radio communication system capable of improving frequency utilization efficiency more than conventional modulation methods.

This is achieved by the method described below. Nyquist of the second input symbol with a delay difference between the Nyquist signal of the first input symbol and the delay difference of an integral multiple of 1/4 of the symbol period of the above-mentioned input symbol to the Nyquist signal The signal is subjected to quadrature modulation using a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the Nyquist signal as a carrier.

Description of drawings

FIG. 1 is a schematic illustration of conventional digital quadrature modulation (QPSK);

Fig. 2 shows the symbol configuration of the previous quadrature modulation and the reasonable position of the symbols reconsidered according to the Nyquist theory;

FIG. 3 is a diagram of an example of a constellation diagram when a new symbol is added according to the present invention;

FIG. 4 is a diagram representing multiplexing and symbol periods of Nyquist waves;

Fig. 5 is a diagram showing a configuration method of a QPSK ring according to the present invention;

Fig. 6 is a diagram showing the signal arrangement and method of the modulation wave which is the basis of the present invention;

7 is a waveform diagram for illustration of modulation of a Nyquist wave by a carrier;

Fig. 8 shows that if the frequency of the carrier is set as an odd multiple of the symbol period, then no interference is generated at the T/2 point;

Fig. 9 is a diagram showing that 2 bits can be transmitted in a symbol interval on the I axis and the Q axis if a Nyquist waveform is used;

Fig. 10 is a diagram showing that Nyquist signals are respectively inserted on the I axis and the Q axis at intervals of π;

Fig. 11 is a diagram showing the insertion positions of various new symbols inserted into the I axis and the Q axis in the present invention;

FIG. 12 is a block diagram showing the configuration of a modulation device according to Embodiment 1 of the present invention;

FIG. 13 is a waveform diagram showing a modulation signal obtained by the modulation device of Embodiment 1;

FIG. 14 is a block diagram showing the configuration of a demodulation device according to Embodiment 1 of the present invention;

FIG. 15( a) is a diagram showing a waveform of an input symbol after Nyquist shaping;

FIG. 15( b) is a waveform diagram representing a carrier wave used for primary modulation;

Fig. 15(c) is a waveform diagram showing the primary modulation waveform when the carrier shown in Fig. 15(b) is used for primary modulation by the modulation device of Embodiment 1 using the input symbol of Fig. 15(a);

Fig. 16(a) is a diagram showing an envelope of a secondary modulated wave obtained by the modulation device of Embodiment 1;

Fig. 16(b) is a diagram showing the frequency spectrum of the secondary modulated wave obtained by the modulation device of Embodiment 1;

FIG. 17 is a diagram showing a simulation result of comparing the communication quality of the modulation signal obtained by the modulation device of Embodiment 1 with conventional QPSK and 16QAM;

FIG. 18 is a configuration diagram showing a modulation device according to Embodiment 2;

FIG. 19 is a configuration diagram showing a demodulation device according to Embodiment 2;

FIG. 20 is a configuration diagram showing a modulation device according to Embodiment 3;

FIG. 21 is a configuration diagram showing a demodulation device according to Embodiment 3;

FIG. 22 is a configuration diagram showing a demodulation device according to Embodiment 4. FIG.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1)

Firstly, the inventive process of the present invention and the principle of the present invention will be explained.

The inventor of the present invention thinks that if a 4-dimensional space can be constructed on the I-Q plane, the information that can be transmitted in 1 symbol period will become 4 bits (during QPSK), and the frequency efficiency will be doubled.

However, it is impossible to place multiple QPSK rings on the I-Q plane, so as shown in Figure 3, at least a third axis must be added to make it orthogonal on the I-Q plane. This necessity is self-evident. But what kind of physical quantities are used to make the new axes? In the present invention, the third axis (z axis) is considered as the phase dimension.

Here, accommodating two QPSK loops in one symbol period means that two Nyquist waves are arranged on the I-axis, as shown in FIG. 4 . The Nyquist wave constitutes its main part within 2 symbol periods, and its orthogonality can be obtained every symbol period T (time). Therefore, in order to establish the orthogonality of two parts in one symbol period, it is necessary to shorten the symbol period by 1/2 as shown in FIG. 4(b). If the previous method is used to realize, the frequency bandwidth must be expanded by 2 times. In order to improve frequency utilization efficiency, the only way to think of SSB (Single Side Band: Single Side Band) is.

Based on this consideration, the present invention adopts a method of accommodating two Nyquist waves within one symbol period (hereinafter, this method is referred to as double QPSK: double QPSK method).

First explain the configuration method of the QPSK ring in the dual QPSK mode in the present invention, the dual QPSK mode is to realize the mode of multiple phases, if the Z axis is defined as the phase difference component of the phase modulation, then it becomes as shown in Figure 5 (but Figure 5 represents π/2-offset dual: offset QPSK).

The basic idea of the double QPSK method of the present invention is shown in FIG. 6 . In order to facilitate viewing and understanding of this figure, the embodiment has four independent envelopes. It is just like a model in which four independent Nyquist wave envelopes are pasted on a cylinder represented by an analytical signal composed of a carrier wave. In order to accommodate the four Nyquist wave envelopes within one symbol period, an angular difference of 90 degrees is arranged at each symbol point.

Going back to Figure 4 to illustrate, if two Nyquist waves are configured in one symbol period, as shown in Figure 4(a), intersymbol interference will occur, so in the past, at point T/2 Nyquist waves are not configured. The inventors of the present invention have considered that inter-symbol interference can be avoided if the Nyquist wave is modulated at a specific carrier frequency, and thus came up with the present invention.

Now, using FIG. 7, the basic concept of realizing the double QPSK method of the present invention is shown. Figure 7(a) and (b) both repeatedly represent the multiplication of the Nyquist wave of the symbol period T by the cosine wave of the (modulation) period 2T. From this figure, it can be clearly seen that the modulated waveform is also Nyquist Step wave, but the period becomes 1/2 of the original Nyquist wave. If represented by a mathematical formula, the Nyquist wave can be represented by a sinc function. Therefore, the product of the Nyquit wave of the symbol period T and the carrier wave (cosine wave) of the period 2T is expressed by the following formula.

$\frac{\mathrm{<span\; class="notranslate">\; sin</span>}\frac{\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}}{\frac{\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\frac{\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; sin</span>}\frac{\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}}{\frac{\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="sin"\; filenames="A20048001737800321.png,A20048001737800361.png"\; state="\{\{state\}\}">sin</figure-callout></span>}\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;<figure-callout\; id="2"\; label="t\; T"\; filenames="A20048001737800321.png,A20048001737800361.png"\; state="\{\{state\}\}">t</figure-callout></span><figure-callout\; id="2"\; label="t\; T"\; filenames="A20048001737800321.png,A20048001737800361.png"\; state="\{\{state\}\}">\; </figure-callout>}}{\mathrm{<span\; class="notranslate">\; </span>}}}{\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;t</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

It can be seen from (2) that the product (modulation output) is also a sinc function, and the period becomes T/2. Therefore, even if the modulated signal is added, there will be no mutual interference phenomenon. Fig. 7(c) is a waveform diagram showing the synthesis.

As described above, the cosine wave (carrier) is multiplied by the two Nyquist signals, and these two Nyquist waves are Nyquis that give each other a delay difference that is an integer multiple of 1/4 of the symbol period Tebo, this is the first requirement of the present invention. Accordingly, the two Nyquist signals multiplied by the cosine wave (that is, modulated) become non-interfering with each other.

However, since the carrier wave with a period of 2T contains a DC (direct current) domain after modulation, it is necessary to increase the carrier frequency. However, if the carrier frequency is simply increased, the symbol points of the Nyquist waves interfere with each other.

The second necessary condition of the present invention is that the frequency of the above-mentioned cosine wave (carrier) is set as an odd multiple of the fundamental frequency of the Nyquist signal, that is, the period of the multiplied cosine wave (carrier) is regarded as 2T/( 2n+1). FIG. 8 is a waveform diagram showing a case where a Nyquist waveform is multiplied by a carrier wave having a period of 2T/(2n+1) (example of n=0, 1, 2). It can be seen from FIG. 8 that, as in the present invention, if odd harmonics having 2T as the fundamental period are used, the symbol points of the Nyquist waves arranged every T/2 can not be disturbed. In addition, FIG. 8 shows the state of the waveform when the period of the carrier wave is 2T, 2T/3, and 2T/5.

That is, the gist of the present invention is to set the quadrature modulator, and use the cosine of the frequency with an odd multiple of the fundamental frequency of the Nyquist signal as a carrier wave, and to the Nyquist signal of the first input symbol and the Nyquist signal Quadrature modulation is performed on the Nyquist signal of the second input symbol whose special signal has a delay difference that is an integer multiple of 1/4 of the symbol period of the input symbol. If such a quadrature modulator is provided, even when double quadrature modulation is performed, 4 Nyquist signals can be arranged within 1 symbol period, and no interference will be generated between the Nyquist signals, Therefore, twice as many conventional symbols can be accommodated within the same frequency bandwidth.

The principle of the present invention is further described from another angle. FIG. 9 shows that if a Nyquist waveform is used, 2 bits can be transmitted in 1 symbol period on the I axis and the Q axis. It is well known that there is a phase difference of π/2 in the quadrature modulation between the I axis and the Q axis.

FIG. 10 is a diagram showing a 4-dimensional space constructed by adding new 2 axes of the present invention to the conventional 2-dimensional signal correspondence (constellation diagram) of the I axis and the Q axis. Therefore, the four axes of I-axis (negative), Q-axis (negative), S-axis (negative), and T-axis (negative) in Figure 10 are all independent of each other, and the constellation diagram formed by them becomes 4-dimensional . In addition, the dotted line in FIG. 10 indicates that one modulation can be performed to arrange symbols one by one. As shown in the figure, Nyquist signals are inserted at intervals of π on the I-axis and Q-axis respectively. At this time, the orthogonality of the Nyquist signals cannot be compared between the previous phase point and the new phase point, that is, they cannot be opposite to each other. The signal point for is guaranteed to be Null.

Therefore, in the present invention, as shown in FIG. 7, in order to configure symbols to new phase points, instead of simply adding new symbols to previous symbols, multiplied by a cosine wave (carrier), make it orthogonal. Furthermore, as described above, by making the cosine wave (carrier) a frequency having an odd multiple of the fundamental frequency of the Nyquist signal, it is possible to suppress the expansion of the frequency bandwidth.

FIG. 11 is a diagram showing insertion positions of new symbols on the I axis and the Q axis in the present invention. As can be seen from this figure, in the present invention, quadrature modulation is performed on two signals having a phase difference relationship of π. In other words, double quadrature modulation is performed in the present invention.

FIG. 12 is a diagram showing a configuration of a modulation device according to Embodiment 1 of the present invention. The modulation device 100 is a transmitter setting a wireless communication system. The modulation device 100 performs quadrature modulation and double QPSK processing on the information of the 4 systems, including: adding quartering of the symbol interval T to the data signals (input symbols) Bit1, Bit2, Bit3, and Bit4 of the 4 systems The delayer group 102,103,104 of one delay difference; With the signal of the delay difference of 1/2 of symbol interval T as the first and the 2nd quadrature modulator 109,110 of input 2 groups; The outputs of the quadrature modulators 109 and 110 are input to the third quadrature modulator 113 .

The modulation device 100 parallelizes the transmission data (TXData) into 4 series through the serial/parallel conversion circuit (S/P) 101, and then adds codes to the parallelized bits Bit1, Bit2, Bit3, and Bit4 through the delayers 102, 103, and 104. The delay difference of T/4 of 1/4 of the meta-period T. Through this kind of processing, the signal is arranged at the 4 equally divided phase points in the symbol interval, that is, arranged at the positions of phase zero, phase π/2, and phase 3π/2.

The modulation device 100 forms four delayed signals through the respective Nyquist filters 105, 106, 107, and 108, and divides them into two signals with a delay difference relationship of T/2 (that is, a relationship of phase difference π). The 2 groups are input to the first quadrature modulator 109 and the second quadrature modulator 110 .

The first quadrature modulator 109 performs primary modulation on the Nyquist signal with a carrier wave having a period of 2T/(2n+1) (n: integer), and synthesizes the input 2 signals. Similarly, the second quadrature modulator 110 performs primary modulation on the Nyquist signal with a carrier wave having a period of 2T/(2n+1) (n: integer), and synthesizes two input signals.

The modulated signals of the 2 systems obtained after the above-mentioned processing are input into band-pass filters (BPF) 111, 112, and the image signals and spurious components generated by the primary modulation are removed by the band-pass filters 111, 112, and the filtered signal It is sent to the third quadrature modulator 113 .

The third quadrature modulator 113 performs quadrature modulation (secondary modulation) on the input 2-system modulation signal with a high frequency (ω _c ). The secondarily modulated signal output from the third quadrature modulator 113 passes through the bandpass filter 114 to remove the image signal and spurious components, and then is sent to the wireless transmission path.

Accordingly, modulation apparatus 100 can obtain modulated signals in which four pieces of input signal information are accommodated as Nyquist waves each having a difference of 90° within one symbol period. Fig. 13 is a conceptual diagram thereof. In the I-axis signal, there is a Nyquist composite wave of 2 signals accommodated by a difference of T/2. In the Q-axis signal, there is a Nyquist synthesized wave activated by a difference of T/4 from that of the I-axis. Four signal points appear on the envelope at times t1, t2, t3, and t4 juxtaposed by a time difference of 1/4 of the symbol period T.

FIG. 14 is a configuration diagram showing a demodulation device 200 that demodulates a modulated signal formed by the modulation device 100 . The demodulation device 200 is provided on the receiving side of the wireless communication system. The demodulation device 200 inputs the modulated signal to the first quadrature demodulator 201, and the first quadrature demodulator 200 performs quadrature modulation on the input modulated signal through high frequency (ω _c ) to obtain the first and second solutions tone signal.

Such two-system demodulated signals are input to second and third quadrature demodulators 204 and 205 through bandpass filters 202 and 203 . The second and third quadrature demodulators 204 and 205 each perform quadrature demodulation of an input signal using a carrier wave of a cycle 2T/(2n+1), (n: integer).

Next, the 4-system demodulated signals output from the second and third quadrature demodulators 204, 205 pass through Nyquist filters 206, 207, 208, 209 and delayer groups 210, 211, 212 to become demodulated bits Bit1, Bit2, Bit3, Bit4, this group of delayers is used to add a quarter of the delay difference of the symbol interval T. The demodulated bits Bit1, Bit2, Bit3, and Bit4 are serialized by the parallel/serial conversion circuit (P/S) 213, and received data (RXout: RX output) is thus obtained.

As described above, if the demodulation device 200 is used, the signal modulated by the modulation device 100 can be satisfactorily demodulated, and the original unmodulated bits can be restored.

Next, for a wireless communication system in which the modulation device 100 shown in FIG. 12 is installed on the transmitter side and the demodulation device 200 shown in FIG. 14 is installed on the receiver side, the modulation operation was confirmed and the BER was measured in an AWGN environment. simulation and describe it.

The important content in the present invention is whether the Nyquist wave can be arranged on 1/2 of the symbol period, which is the content that needs to be confirmed in one modulation. Fig. 15 is a graph showing the results of an experiment to confirm this. Fig. 15(a) shows symbol input (after Nyquist shaping), Fig. 15(b) shows a carrier wave for primary modulation, and Fig. 15(c) shows a primary modulated output signal. In addition, they all correspond to one of the I-axis and the Q-axis. If you look at the Nyquist input in Figure 15(a) and the primary modulation output in Figure 15(c), you can know that the signal point of the Nyquist wave is indeed represented.

Fig. 16 is a diagram showing a frequency spectrum showing a secondary modulated output wave and its frequency bandwidth. In secondary modulation, I-axis components and Q-axis components are synthesized by quadrature modulation, and four types of envelopes are synthesized ( FIG. 16( a )). In addition, it can be seen from the frequency spectrum ( FIG. 16( b )) that the frequency bandwidth is 1 hertz (Hz). The input symbol cycle was simulated as 1 second (sec) (Nyquist wave cycle: 0.5 Hz), and the two-sided wave was generated by modulation, and it became 1 Hz/-3 dB, which shows theoretical correctness.

Secondly, the communication quality of the modulation method of the present invention is better than that of 16QAM, which is a major premise for improving frequency utilization efficiency. Fig. 17 is a graph showing the simulation results of BER versus S/N in an AWGN environment. From the simulation results, it can be seen that the BER of the modulation method of the present invention is roughly equal to that of QPSK, and compared with 16QAM having the same transmission rate, it has the advantage of maintaining S/N characteristics above 4dB even at point 10 ^-2 .

In this way, according to the present embodiment, by providing the following three quadrature modulators, it is possible to realize the modulation device 100 for forming a modulated signal that accommodates a conventional double signal without expanding the bandwidth. The 1st, the 2nd quadrature modulator 109,110: input respectively have the Nyquist signal of the delay difference of 1/2 (2/4) of symbol period, to the Nyquist signal of input, will have A cosine wave of an odd multiple of the fundamental frequency of the Nyquist signal is used as a carrier for quadrature modulation, and a third quadrature modulator 113: uses a carrier of a predetermined frequency to obtain the first quadrature modulator 109 The modulated signal and the modulated signal obtained by the second quadrature modulator 110 are subjected to quadrature modulation.

(Embodiment 2)

In Embodiment 1 described above, the amount of information that can be transmitted in one symbol period is 4 bits, which is equivalent to conventional 16QAM. On the other hand, among the conventional modulation schemes, there is a multi-value scheme such as 64QAM for practical purposes. In this embodiment, the efficiency is further improved by the modulation method, and a method corresponding to the conventional multi-value conversion is proposed.

FIG. 18 is a configuration diagram of a modulation device according to Embodiment 2 of the present invention. In FIG. 18 , the same reference numerals are used for parts corresponding to those in FIG. 12 , and explanations for these parts are omitted. The modulation device 300 inputs the transmission data (TXData) into the mapping processing unit 301, and the mapping processing of the mapping processing unit 301 mainly performs parallelization processing and error correction coding on the transmission data (TXData). The mapping processing section 301 sends the processed 1st bit and the 2nd bit to the adder 302, sends the 3rd bit and the 4th bit to the adder 304, and sends the 5th bit and the 6th bit to the adder 304. To the adder 303, the 7th bit and the 8th bit are sent to the adder 305.

Each of the adders 302 to 305 arranges 2-bit signals by adding the input 2-bit signals. The output of the adder 302 is sent to the Nyquist filter 105, and the outputs of the other adders 303-305 are sent to the Nyquist filters 106-108 through the delayers 102-104. Through these processes, the Nyquist signals output from the respective Nyquist filters 105 to 108 have 2 bits of information per wave, and the subsequent processing is the same as in FIG. 12 .

FIG. 19 is a configuration diagram of a demodulation device 400 that demodulates a modulated signal formed by the modulation device 300 . The demodulation device 400 is set at the receiving side of the wireless communication system. In addition, in FIG. 19 , the same reference numerals are used for parts corresponding to those in FIG. 14 , and descriptions of these parts are omitted. The demodulator 400 is equipped with analog-digital converters (A/D) 401 to 404 for analog-to-digital conversion of the Nyquist signal, and is equipped with a demapping processing unit 405, which is similar to the demodulator of FIG. 14 The composition of 200 is the same.

Each of the analog-to-digital conversion circuits 401 to 404 obtains information in 2-bit units by threshold determination of the Nyquist signals output from the Nyquist filters 206 to 209 . The demapping processing unit 405 obtains received data (RXout) by performing demapping processing mainly including serialization processing and error correction decoding on the input 8-system bits.

In this way, according to this embodiment, adding the structure of Embodiment 1, by processing the multivalued Nyquist signal itself, it is possible to transmit twice the frequency of Embodiment 1 within the same frequency bandwidth as Embodiment 1. data, further improving frequency utilization efficiency.

(Embodiment 3)

In Embodiment 1 shown in FIG. 12 and Embodiment 2 shown in FIG. 18 , the transmission data that is a parallel signal is arranged in symbols at phase points that are equally divided into four in the symbol interval, that is, the arrangement After the positions of phase zero, phase π/2, phase π, and phase 3π/2, the quadrature modulation of the symbols of phase zero and phase π is carried out through one modulation, and phase π/2 and phase 3π/ Orthogonal modulation of 2 symbols, that is, primary modulation of symbol signals with a phase difference of π (that is, a delay difference of 1/2 of the symbol period).

As a result, the receiver performs quadrature demodulation with a phase difference of π/2 in the first stage, but the quadrature demodulation in an environment with severe dynamic changes may increase the error between phases compared with the demodulation with a phase difference of π. Intersymbol interference and distortion fading in transmission are generated. Therefore, in this embodiment, symbols having a phase difference of π/2 (that is, a delay difference of 1/4 of the symbol period) are processed by the first and second quadrature modulation processes.

FIG. 20 , which uses the same symbols as those in FIG. 18 , is a configuration diagram of modulation device 500 according to Embodiment 3 of the present invention. As mentioned above, the Nyquist signal with a delay difference of 1/4 of the symbol period is input through the first and second quadrature modulators 501, 502, and the usual quadrature modulation with a phase difference of π/2 is performed. Let the carrier frequency used be ω _c . On the other hand, since the phase difference π is combined by the third quadrature modulator 503, the carrier frequency used is (2n+1)ω _o . At this time, in order to surely reduce the interference at the symbol half-period point of (2n+1) _ωo , _ωc should be set as an even multiple of _ωo .

FIG. 21 , which uses the same symbols for corresponding portions as those in FIG. 19 , is a configuration diagram of demodulation device 600 according to Embodiment 3 of the present invention. The demodulation device 600 is provided on the receiving side, and demodulates the modulated signal transmitted after being modulated by the modulating device 500 provided on the sending side.

In the demodulation device 600, the carrier frequency used in the first quadrature modulator 601 is (2n+1)ω _o . On the other hand, since normal quadrature demodulation with a phase difference of π/2 is performed by the second and third quadrature demodulators 602 and 603, the carrier frequency to be used is ω _c .

As described above, according to this embodiment, adding the effects of Embodiment 1 and Embodiment 2, it is possible to realize a modulation system that further reduces intersymbol interference and distortion during transmission.

In addition, although it is described in this embodiment, the Nyquist signal having a delay difference of 1/4 of the symbol period is modulated once with a predetermined carrier frequency _ωc , and then the 2-system obtained by the one-time modulation A case where a signal is re-modulated using a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the Nyquist signal as a carrier. But the delay difference is not limited to 1/4 cycle, even 3/4 cycle is fine. In short, it is only necessary to perform one modulation on a signal having a delay difference that is an odd multiple of the 1/4 period of the symbol period.

(Embodiment 4)

In this embodiment, a case where quadrature modulation is performed using a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the Nyquist signal as a carrier wave is described when a quadrature modulator is realized with another configuration. Its basic principle is the same as Embodiments 1-3.

In FIG. 22 , which uses the same symbols as those in FIG. 12 , modulation device 700 according to this embodiment includes shift registers 701 and 702 as first and second modulators that perform primary modulation. The modulation device 700 inverts the polarity of one of the Nyquist signals of the two systems input to the shift registers 701 and 702 through the inverters 703 and 704 . Polarity inversion is implemented for bit 3 and bit 4 in this embodiment.

After these processes, the modulation device 700 obtains the positive signal bit 1 of the I axis and the negative signal bit 3 of the I axis, and also obtains the positive signal bit 2 of the Q axis and the negative signal bit 4 of the Q axis.

The positive signal bit 1 of the I axis and the negative signal bit 3 of the I axis thus obtained are input to the shift register 701, and at the same time, the positive signal bit 2 of the Q axis and the negative signal bit 4 of the Q axis are input to the shift register 702.

The shift register 701 outputs a clock with an odd multiple of the period while inserting zeros between the positive signal bit 1 of the I axis and the negative signal bit 3 of the I axis. Similarly, the shift register 702 outputs a clock with an odd multiple of the symbol period while inserting zeros between the Q-axis positive signal bit 2 and the Q-axis negative signal bit 4 .

In other words, each of the shift registers 701 and 702 inputs a Nyquist signal having a delay difference that is an integer multiple of 1/4 of the symbol period (in this embodiment, 1/2 of the symbol period), and uses Odd multiples of the fundamental frequency of the Quest signal alternately output the input Nyquist signal.

This kind of processing is equivalent to using a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the Nyquist signal as a carrier, and having an input code for the Nyquist signal of the first input symbol and the Nyquist signal for this Nyquist signal. Quadrature modulation is performed on the Nyquist signal of the second input symbol with a delay difference that is an integer multiple of 1/4 of the symbol period.

In addition, the serial/parallel converter (S/P) 101, the shift registers 701 and 702, and the quadrature modulator 113 each operate based on a clock signal from a clock generator 705 that generates an independent clock.

As a result, modulated outputs having symbols of 2 bits each for the I axis and the Q axis as shown in FIG. 6 are obtained from the bandpass filter 114 .

The present invention is not limited to the above-described embodiments, and can be implemented with various modifications.

One form of the modulation method of the present invention is a modulation method in which the first input symbol and the second input symbol are orthogonally modulated, and the Nyquist signal of the first input symbol and the Nyquist signal given to the first input symbol are The Nyquist signal of the 2nd input symbol having the delay difference of an integer multiple of the 1/4 cycle of the symbol period of the above-mentioned input symbol will have an odd-number multiple of the fundamental frequency of the above-mentioned Nyquist signal. The cosine wave is used as a carrier for quadrature modulation.

If this method is used, the cosine wave (carrier) can be used to perform quadrature modulation on the first and second Nyquist signals having a delay difference that is an integer multiple of the 1/4 period of the input symbol period T, so that the first The 1st and 2nd Nyquist signals do not interfere with each other, and are all accommodated within 1 symbol period T of the input symbol. But if only this method is used, it has a DC component. Therefore, if secondary modulation is performed, the frequency bandwidth will be doubled as a result. For this reason, the above-mentioned cosine wave is selected to have an odd multiple of the fundamental frequency of the Nyquist signal. As a result, the symbol points of the Nyquist wave are arranged at every T/2 point, and the signals are mutually Do not interfere. That is, at each T/2 point, two Nyquist waves can be formed in a relationship that when one Nyquist wave becomes the maximum, the other Nyquist wave becomes blank. Through such processing, the frequency bandwidth is not expanded, and a modulated signal that can accommodate a conventional double signal can be formed.

In addition, another aspect of the modulation method of the present invention is as follows: a delay difference of 1/4 cycle of the symbol period is given to each of the input symbols of the 4 systems, and Nyquist is shaped to obtain a signal having a symbol period. The step of the 1st～the 4th Nyquist signal of the delay difference of 1/4 cycle; With the cosine wave of the frequency of the odd multiple times of the basic frequency of above-mentioned Nyquist signal as carrier, to have symbol period respectively The first and second Nyquist signals with a delay difference of 2/4 cycle and the 3rd and 4th Nyquist signals with a delay difference of 2/4 cycle of the symbol period perform quadrature modulation on the primary modulation step and using a predetermined frequency carrier, the quadrature modulation signals of the above-mentioned first and second Nyquist signals and the quadrature modulation signals of the above-mentioned 3rd and 4th Nyquist signals obtained through a modulation step A secondary modulation step of quadrature modulation is performed.

In addition, another aspect of the modulation method of the present invention is as follows: a delay difference of 1/4 cycle of the symbol period is given to each of the input symbols of the 4 systems, and Nyquist is shaped to obtain a signal having a symbol period. Steps of the first to fourth Nyquist signals with a delay difference of 1/4 cycle; the first and second Nyquist signals with a delay difference of 1/4 cycle of the symbol period with a carrier of a predetermined frequency And a modulation step of quadrature modulation with the 3rd and 4th Nyquist signals with a delay difference of 1/4 cycle of the symbol period; The cosine wave is used as a carrier wave, respectively for the quadrature modulation signals of the above-mentioned first and second Nyquist signals and the quadrature modulation signals of the above-mentioned third and fourth Nyquist signals obtained from the above-mentioned primary modulation step A secondary modulation step of quadrature modulation is performed.

If these methods are used to obtain the modulated signal through the secondary modulation step, compared with the simple quadrature modulation of two Nyquist signals, the frequency bandwidth will not expand, and it is related to the 1st to 4th input symbols The first to fourth Nyquist signals are arranged so as not to interfere with each other. Therefore, it is possible to obtain a modulated signal in which twice as many symbols that do not interfere with each other are arranged in the same frequency bandwidth as conventional ones.

Another form of the modulation device of the present invention adopts a configuration that includes: inputting the first Nyquist signal related to the first input symbol and having a period of 1/4 of the period of the input symbol for the Nyquist signal. For the 2nd Nyquist signal related to the 2nd input symbol of the delay difference of integer multiples, use the cosine wave having the frequency of an odd multiple of the fundamental frequency of these Nyquist signals for the 1st and 2nd Nyquist signals A quadrature modulator for quadrature modulation of the Stern signal.

If such a structure is adopted, since the first and second Nyquist signals having a delay difference that is an integer multiple of the 1/4 period of the input symbol period T are quadrature modulated using a cosine wave (carrier), the first The 1st and 2nd Nyquist signals do not interfere with each other, and all of them can be accommodated within 1 symbol period T of the input symbol. In addition, since the frequency of the cosine wave is selected to be an odd multiple of the fundamental frequency having the Nyquist signal, the direct current component can be controlled, and the frequency band will not substantially expand even if secondary modulation is performed. Therefore, it is possible to form a modulated signal that accommodates twice as many symbols as conventional ones without widening the bandwidth.

In addition, another form of the modulation device of the present invention adopts a structure that includes: a group of delayers that give a delay difference of 1/4 period of the symbol period to each of the input symbols of the 4 systems; Nyquist filter The device forms Nyquist signals from the symbols of the above-mentioned 4 systems respectively; the first and second quadrature modulators input the Nyquist signals respectively having a delay difference of 2/4 period of the symbol period, for all The input Nyquist signal uses a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the above-mentioned Nyquist signal as a carrier to carry out quadrature modulation; and the modulated signal obtained by the first quadrature modulator and the A third quadrature modulator that quadrature-modulates the modulated signal obtained by the second quadrature modulator using a carrier of a predetermined frequency.

In addition, another aspect of the modulation device of the present invention adopts a structure that includes: a group of delayers that give a delay difference of 1/4 period of the symbol period to each of the input symbols of the 4 systems; a Nyquist filter , respectively form Nyquist signals from the symbols of the above-mentioned 4 systems; the first and second quadrature modulators input the Nyquist signals with odd multiples of the delay difference of the 1/4 period of the symbol period respectively, and performing quadrature modulation using a carrier of a predetermined frequency; and using the modulated signal obtained by the first quadrature modulator and the modulated signal obtained by the second quadrature modulator using the basic frequency that will have the above-mentioned Nyquist signal A third quadrature modulator that performs quadrature modulation with a cosine wave of an odd multiple of frequency as a carrier.

With these configurations, a modulated signal in which two Nyquist signals are arranged so as not to interfere with each other is obtained within one symbol period T by the first quadrature modulator. At the same time, through the second quadrature modulator, a modulated signal in which two Nyquist signals are arranged in a non-interfering state can be obtained within one symbol period T. Through the third quadrature modulator, the modulated signal in which four Nyquist signals are arranged in a non-interference state can be obtained within one symbol period T. As a result, the frequency bandwidth is not expanded, and the conventional 2 times the modulation signal of the symbol.

In addition, the structure adopted by another form of the modulation device of the present invention is to have: a delayer group, which gives a delay difference of 1/4 period of the symbol period to each of the input symbols of the 4 systems; Nyquist filter The device forms Nyquist signals from the symbols of the above-mentioned 4 systems respectively; the first and second quadrature modulators input the Nyquist signals with delay differences that are integer multiples of the 1/4 period of the symbol period respectively , the input Nyquist signal is used to alternately output the frequency having an odd multiple of the fundamental frequency of the above Nyquist signal; and the modulated signal obtained by the first quadrature modulator and the second quadrature modulator A third quadrature modulator that quadrature-modulates the modulated signal obtained by the quadrature modulator using a carrier of a predetermined frequency.

With such a configuration, it is possible to realize a modulated signal that accommodates twice the conventional signal without expanding the frequency bandwidth. At the same time, the first and second quadrature modulators can be constituted by switching elements, shift registers, and the like.

One form of the demodulation device of the present invention adopts a structure in which: the modulated signal formed by quadrature modulation of the first and second Nyquist signals uses an odd multiple of the fundamental frequency of the above-mentioned Nyquist signal. A quadrature demodulator for quadrature demodulation of the cosine wave of the frequency.

In addition, another aspect of the demodulation device of the present invention adopts a configuration which includes: inputting a modulated signal, performing quadrature demodulation on the modulated signal using a predetermined carrier frequency, thereby obtaining the first and second demodulated signals The 1st quadrature demodulator; use the cosine wave having the frequency of the odd multiple times of the basic frequency of the above-mentioned Nyquist signal, carry out quadrature demodulation to the 1st demodulation signal, thereby obtain the 3rd and the 4th demodulation signal and using a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the above-mentioned Nyquist signal, quadrature demodulates the 2nd demodulated signal, thereby obtaining the 5th and 6th solutions The third quadrature demodulator of the modulated signal.

In addition, the structure adopted by another demodulation device of the present invention is equipped with: an input modulated signal, using a cosine wave having a frequency that is an odd multiple of the fundamental frequency of the above-mentioned Nyquist signal to perform quadrature demodulation on the modulated signal, Thereby obtain the first quadrature demodulator of the 1st and the 2nd demodulation signal; Use predetermined carrier frequency to carry out quadrature demodulation to above-mentioned 1st demodulation signal, thereby obtain the 2nd of the 3rd and the 4th demodulation signal a quadrature demodulator; and a third quadrature demodulator for performing quadrature demodulation on the second demodulated signal using a predetermined carrier frequency to obtain fifth and sixth demodulated signals.

With the above configuration, it is possible to satisfactorily demodulate a modulated signal demodulated using the modulation device of the present invention to obtain a demodulated signal.

A wireless communication system according to the present invention is configured to include the modulation device described above and the demodulation device described above.

If these configurations are adopted, a wireless communication system that communicates at twice the conventional transmission speed on the same frequency as conventional ones can be realized.

As described above, according to the present invention, it is possible to realize a modulation method with a frequency utilization efficiency more than double that of the conventional art.

This specification is based on the application number 2003-35750 filed on February 13, 2003, the application number 2003-136610 filed on May 14, 2003, and the application number 2003-382985 filed on November 12, 2003 Japanese patent application. Its entire content is contained here.

Possibility of industrial use.

The present invention is widely applicable to wireless communication, for example, to mobile communication telephones and base stations thereof.

Claims (13)

1, a kind of the 1st input symbols and the 2nd input symbols are carried out the modulator approach of quadrature modulation, comprising:

With the Nyquist signal of above-mentioned the 1st input symbols with this Nyquist signal has been given the Nyquist signal of above-mentioned the 2nd input symbols of delaying difference of integral multiple in 1/4 cycle of the code-element period of above-mentioned input symbols, the cosine wave of frequency of odd-multiple that use will have the fundamental frequency of above-mentioned Nyquist signal carries out quadrature modulation as carrier wave.

2, modulator approach as claimed in claim 1 comprises:

Each of the input symbols of 4 systems is given code-element period 1/4 cycle delay poorly, Nyquist is shaped, thereby obtains to have the step of the 1st～the 4th Nyquist signal of delaying difference in 1/4 cycle of code-element period;

The cosine wave of frequency of odd-multiple of fundamental frequency that will have above-mentioned Nyquist signal is as carrier wave, respectively the 1st and the 2nd Nyquist signal of delaying difference in 2/4 cycle with code-element period and the 3rd, the 4th Nyquist signal of delaying difference with 2/4 cycle of code-element period carried out the primary modulation step of quadrature modulation; And

Use the carrier wave of predetermined frequency, the orthogonal demodulation signal of the orthogonal demodulation signal of the above-mentioned the 1st and the 2nd Nyquist signal that are obtained through the primary modulation step and above-mentioned the 3rd, the 4th Nyquist signal is carried out the secondary modulation step of quadrature modulation.

3, modulator approach as claimed in claim 1 comprises:

Each of the input symbols of 4 systems is given code-element period 1/4 cycle delay poorly, Nyquist is shaped, thereby obtains to have the step of the 1st～4 Nyquist signal of delay difference in 1/4 cycle of code-element period;

The the 1st and the 2nd Nyquist signal of delaying difference in 1/4 cycle with code-element period and the 3rd and the 4th Nyquist signal of delaying difference with 1/4 cycle of code-element period are carried out the primary modulation step of quadrature modulation with the carrier wave of preset frequency; And

The cosine wave of frequency of odd-multiple that will have the fundamental frequency of above-mentioned Nyquist uses as carrier wave, respectively to the orthogonal demodulation signal of the above-mentioned the 1st and the 2nd Nyquist signal that from above-mentioned primary modulation step, are obtained and the above-mentioned the 3rd and the orthogonal demodulation signal of the 4th Nyquist signal carry out the secondary modulation step of quadrature modulation.

4, a kind of modulating device comprises:

Import the 1st Nyquist signal relevant and this Nyquist signal is had the 2nd Nyquist signal relevant of delaying difference of integral multiple in 1/4 cycle in input symbols cycle, use the cosine wave of frequency of the odd-multiple of fundamental frequency this 1st and the 2nd Nyquist signal to be carried out the quadrature modulator of quadrature modulation with these Nyquist signals with the 2nd input symbols with the 1st input symbols.

5, modulating device as claimed in claim 4 comprises:

Each of the input symbols of 4 systems is given code-element period 1/4 cycle delay difference delay the device group;

Form the nyquist filter of Nyquist signal respectively from the code element of above-mentioned 4 systems;

Input has the Nyquist signal of delaying difference in 2/4 cycle of code-element period respectively, the Nyquist signal imported is used the cosine wave of frequency of the odd-multiple of the fundamental frequency that will have above-mentioned Nyquist signal carry out the 1st and the 2nd quadrature modulator of quadrature modulation as carrier wave; And

The modulation signal that will be obtained by above-mentioned the 1st quadrature modulator and use the carrier wave of preset frequency to carry out the 3rd positive intermodulation device of quadrature modulation by the modulation signal that above-mentioned the 2nd quadrature modulator is obtained.

6, modulating device as claimed in claim 4 comprises:

Each of the input symbols of 4 systems is given code-element period 1/4 cycle delay difference delay the device group;

Form the nyquist filter of Nyquist signal respectively from the code element of above-mentioned 4 systems;

Import the Nyquist signal of delaying difference of the odd-multiple in 1/4 cycle that has code-element period respectively, and the carrier wave of use preset frequency carries out the 1st and the 2nd quadrature modulator of quadrature modulation; And

The modulation signal that will be obtained by above-mentioned the 1st quadrature modulator and use the cosine wave of frequency of the odd-multiple of the fundamental frequency that will have above-mentioned Nyquist signal to carry out the 3rd positive intermodulation device of quadrature modulation as carrier wave by the modulation signal that above-mentioned the 2nd quadrature modulator is obtained.

7, a kind of modulating device comprises:

Each of the input symbols of 4 systems is given code-element period 1/4 cycle delay difference delay the device group;

Form the nyquist filter of Nyquist signal respectively from the code element of above-mentioned 4 systems;

Input has the Nyquist signal of delaying difference of integral multiple in 1/4 cycle of code-element period respectively, the 1st and the 2nd quadrature modulator that uses the frequency of the odd-multiple of the fundamental frequency that will have above-mentioned Nyquist signal to export alternately to the Nyquist signal imported; And

The modulation signal that will be obtained by above-mentioned the 1st quadrature modulator and use the carrier wave of preset frequency to carry out the 3rd positive intermodulation device of quadrature modulation by the modulation signal that above-mentioned the 2nd quadrature modulator is obtained.

8, a kind of demodulating equipment comprises:

The modulation signal that the 1st and the 2nd Nyquist signal is formed by quadrature modulation, the quadrature demodulator that uses the cosine wave of frequency of the odd-multiple of fundamental frequency to carry out quadrature demodulation with above-mentioned Nyquist signal.

9, demodulating equipment as claimed in claim 8 comprises:

Input modulating signal uses predetermined carrier frequency that this modulation signal is carried out quadrature demodulation, thereby obtains the 1st quadrature demodulator of the 1st and the 2nd restituted signal;

The cosine wave of frequency of odd-multiple that use has the fundamental frequency of above-mentioned Nyquist signal carries out quadrature demodulation to above-mentioned the 1st restituted signal, thereby obtains the 2nd quadrature demodulator of the 3rd and the 4th restituted signal; And

The cosine wave of frequency of odd-multiple that use has the fundamental frequency of above-mentioned Nyquist signal carries out quadrature demodulation to above-mentioned the 2nd restituted signal, thereby obtains the 3rd quadrature demodulator of the 5th and the 6th restituted signal.

10, demodulating equipment as claimed in claim 8 comprises:

Input modulating signal uses the cosine wave of frequency of the odd-multiple of the fundamental frequency with above-mentioned Nyquist signal that this modulation signal is carried out quadrature demodulation, thereby obtains the 1st quadrature demodulator of the 1st and the 2nd restituted signal;

Use predetermined carrier frequency that above-mentioned the 1st restituted signal is carried out quadrature demodulation, thereby obtain the 2nd quadrature demodulator of the 3rd and the 4th restituted signal; And

Use predetermined carrier frequency that above-mentioned the 2nd restituted signal is carried out quadrature demodulation, thereby obtain the 3rd quadrature demodulator of the 5th and the 6th conciliation signal.

11, a kind of wireless communication system possesses modulating device as claimed in claim 4 and demodulating equipment as claimed in claim 8.

12, a kind of wireless communication system possesses modulating device as claimed in claim 5 and demodulating equipment as claimed in claim 9.

13, a kind of wireless communication system possesses modulating device as claimed in claim 6 and demodulating equipment as claimed in claim 10.

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