WO2014005323A1

WO2014005323A1 - Signal modulation method and device

Info

Publication number: WO2014005323A1
Application number: PCT/CN2012/078289
Authority: WO
Inventors: 左天健
Original assignee: 华为技术有限公司
Priority date: 2012-07-06
Filing date: 2012-07-06
Publication date: 2014-01-09
Also published as: CN102893568A; CN102893568B

Abstract

Embodiments of this application provide a signal modulation method and device. According to the embodiments of this application, a first input signal and a second input signal are received, a phase of the first input signal being the same as that of the second input signal, and further, phase shift processing is performed on the first input signal, so as to generate a third input signal, a difference between a phase of the third input signal and that of the first input signal being an odd multiple of π, so that CAP modulation can be performed on the third input signal and the second input signal because a phase difference of an odd multiple of π exists between two input signals that the CAP modulation is performed on.

Description

TECHNICAL FIELD The present application relates to modulation techniques, and in particular, to a method and apparatus for signal modulation. Background technique

From the current and future technology trends, in the short-distance interconnection service, for example, broadband access service or Asynchronous Transfer Mode (ATM) LAN service, carrierless Amplitude Phase can be used. , CAP) modulation technique for data modulation. In CAP modulation, quadrature modulation can be implemented using two filters with a phase difference of π/2. Since the multiplier is not used in the CAP modulation, the bandpass pulse is formed directly by using the shaping filter. The waveform of the in-phase input signal and the waveform of the quadrature input signal reflect the transmitted data stream, so the technique is called "none." Carrier".

This modulation method makes the two demodulated signals obtained by demodulation have large interference between codes of non-sample points. SUMMARY OF THE INVENTION Aspects of the present application provide a method and apparatus for signal modulation for reducing inter-symbol interference of demodulated two demodulated signals at non-sampling points.

In an aspect of the present application, a method for modulating a signal is provided, including:

Receiving a first input signal and a second input signal, the first input signal being in the same phase as the second input signal;

Performing phase shift processing on the first input signal to generate a third input signal, the phase of the third input signal being different from the phase of the first input signal by an odd multiple of π;

The third input signal and the second input signal are CAP modulated.

In a first possible implementation, the first input signal and the second input signal comprise a non-return-to-zero signal or a pulse amplitude modulated signal.

In conjunction with the first possible implementation, in a second possible implementation, the CAP modulating the third input signal and the second input signal includes: The CAP modulation is performed on the third input signal and the second input signal by using a Gaussian filter.

In another aspect of the present application, a signal modulation apparatus is provided, including:

a receiver, configured to receive the first input signal and the second input signal, and transmit the first input signal to a phase shifter, and transmit the second input signal to a signal modulator, the first input signal and The second input signal has the same phase;

The phase shifter is configured to perform phase shift processing on the first input signal, generate a third input signal, and transmit the third input signal to the signal modulator, the third input signal and the The phase of the first input signal is different by an odd multiple of π;

The signal modulator is configured to perform the third input signal and the second input signal

CAP modulation.

In conjunction with the first possible implementation, in a second possible implementation, the signal modulator is specifically used

The CAP modulation is performed on the third input signal and the second input signal by using a Gaussian filter.

a receiver, configured to receive the first input signal and the second input signal, and transmit the first input signal to a processor, and transmit the second input signal to a signal modulator, the first input signal The second input signal has the same phase;

The processor, configured to perform phase shift processing on the first input signal, generate a third input signal, and transmit the third input signal to the signal modulator, the third input signal and the The phase of the first input signal differs by an odd multiple of π;

CAP modulation.

In combination with the first possible implementation, in a second possible implementation, the signal modulator is specifically used The CAP modulation is performed on the third input signal and the second input signal by using a Gaussian filter.

In combination with the first possible implementation or the second possible implementation, in a third possible implementation, the signal modulator is further configured to transmit the modulated signal that is modulated by the CAP to a memory; The device also includes a memory for storing the modulated signal.

According to the foregoing technical solution, the first input signal and the second input signal are received by the embodiment of the present application, and the first input signal and the second input signal have the same phase, and then the first input signal is phase-shifted. Processing, generating a third input signal, the third input signal being out of phase with the first input signal by an odd multiple of π, enabling CAP modulation of the third input signal and the second input signal due to The two input signals subjected to CAP modulation have an odd multiple of π, so that the envelope signals of the demodulated two demodulated signals can be separated, thereby reducing the demodulated two demodulated signals in the non-釆Inter-code interference of samples to improve the reliability of CAP modulated signals. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below. The drawings are some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without any inventive labor.

1 is a schematic flowchart of a method for modulating a signal according to an embodiment of the present application;

2 is an eye diagram of an I-channel demodulated signal obtained by demodulating a modulated signal of a CAP modulation in the prior art;

3 is an eye diagram of a demodulated signal of the I channel in the embodiment corresponding to FIG. 1;

4 is another eye diagram of the demodulated signal of the I channel in the embodiment corresponding to FIG. 1;

FIG. 5 is a schematic structural diagram of a signal modulating device according to another embodiment of the present disclosure; FIG. 6 is a schematic structural diagram of a signal modulating device according to another embodiment of the present application; Schematic diagram of the modulation device. detailed description The technical solutions in the embodiments of the present application are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present application. It is a partial embodiment of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

In addition, the term "and/or" in this context is merely an association describing the associated object, indicating that there may be three relationships, for example, A and / or B, which may indicate: A exists separately, and A and B exist simultaneously. There are three cases of B alone. In addition, the character T in this paper generally indicates that the contextual object is an "or" relationship.

FIG. 1 is a schematic flowchart of a method for modulating a signal according to an embodiment of the present invention, as shown in FIG. 1 .

101. Receive a first input signal and a second input signal, where the first input signal and the second input signal have the same phase.

102. Perform phase shift processing on the first input signal to generate a third input signal, where the third input signal is out of phase with the first input signal by an odd multiple of π.

103. Perform CAP modulation on the third input signal and the second input signal.

Optionally, in a possible implementation manner of this embodiment, the first input signal and the second input signal may be a non-returning to zero (NRZ) signal, or may also be a pulse amplitude modulation. (Pulse Amplitude Modulation, PAM) signal.

The transmitting end obtains a modulated signal by performing 101 ~ 103, and transmits it to the receiving end via the transmission channel, and demodulates by the receiving end to obtain two demodulated signals, that is, in-phase (I) demodulated signals and orthogonal ( Quadrature, Q) demodulated signal. Since the first input signal is converted into a third input signal having an odd multiple of the phase difference π before the CAP modulation is performed, the intermodulation interference of the demodulated two demodulated signals at the non-sample point is reduced, FIG. An eye diagram of the I way demodulated signal is shown. 2 is an eye diagram of an I-channel demodulated signal obtained by demodulating a modulated signal of a CAP modulation in the prior art, wherein an Amplitude Unit (AU) represents an amplitude unit and can be any amplitude unit. Compared with Fig. 2, the lateral opening degree of the eye pattern shown in Fig. 3 becomes larger, indicating that the two demodulated signals obtained by demodulation become less inter-code interference at non-sample points.

Optionally, in a possible implementation manner of this embodiment, in 103, the third input signal and the second input signal may be CAP by using a filter with a lower frequency domain roll-off. Modulation, for example, a Gaussian filter. Since the Gaussian filter has smaller jitter than the other filters (for example, the root raised cosine filter) at the position where the π phase difference is shifted, the two demodulated signals obtained by the demodulation can be inter-coded at the sample point. Reduced. Further, when the ΒΤ value is greater than or equal to 0.5, Β is the filter cutoff frequency, Τ is the symbol width, and the jitter of the Gaussian filter at the position where the π phase difference is moved is significantly reduced, so that the two-way solution obtained by the demodulation can be obtained. The intermodulation interference of the modulated signal at the sample point is significantly reduced. Fig. 4 shows another eye diagram of the I-channel demodulated signal of the Gaussian filter with a ΒΤ value of 0.7. Compared with Fig. 3, the longitudinal opening of the eye diagram shown in Fig. 4 becomes larger, indicating that the demodulation is obtained. The two-way demodulated signal has less interference between the code points of the sample points.

It can be understood that, in demodulation, a matched filter corresponding to a filter with a lower frequency domain roll-off used by CAP modulation can be used correspondingly.

Specifically, at the transmitting end, in the CAP modulation in the prior art, the modulated signal can be obtained as

+ B _k g(t)sm( _ac t)

(1) where 4 is the first input signal, the second input signal, , , , , , and are the impulse response of the in-phase filter and the quadrature filter respectively; g (t) is the in-phase filter and positive The shaped filter waveform of the cross filter; is the carrier frequency.

At the receiving end, two orthogonal signals can be obtained by photoelectric conversion and front end amplification, and the two orthogonal signals are respectively recovered by the matched filter corresponding to the in-phase filter and the matched filter corresponding to the orthogonal filter. Demodulated signal, ie, I demodulated signal and Q demodulated signal (for (0 = ∑ ( Λ (0 ® f (ή + _q (ή ® h, (ή) (2) Y _q (ή =∑ ( Λ ( ® + B _q (ή ® h _Q (ή) (3) where h ή and h _Q (ή are matched filters corresponding to the in-phase filter and matched filters of the orthogonal filter respectively) Impulse response, where the term B _k f _Q (ήΘΗ, (ή的结果为: (4)

Where g (is the shaped filter waveform of the matched filter corresponding to the matched filter and the orthogonal filter of the in-phase filter; assume that the result of g(r)®g _mafcft (tr) is 1, sin( (t-2r ))) Filtered out by the filter, when the sample point is an integer multiple of the bit period 7 and 2« = 2W7, « _e + Z, you can get the result of sin^t) in the sample 0, ^WO / ^ t) Is 0. The same is available,

B _k returns the formula (2) and the formula (3), which can be obtained (ή = 4 and [ ) = B _k . At this point, the receiving end can successfully demodulate two demodulated signals.

Since in equation (4), the sin ^ term is not equal to 0 around the sample point (ie, the non-sample point), and the change is steep, this will affect the result of the demodulation signal of the I channel. The data that should be obtained is 4 brings in interference from B _k , which is why the lateral opening is small.

At the transmitting end, by performing 101~103, in the CAP modulation provided by the present invention, the modulated signal can be obtained, that is, the formula (1) becomes

S(t)^A _k g(tT _b /2)cos( _ac tT _b /2) + B _k g(t)sm( _ac t) (6) Correspondingly, equation (4) becomes

(7) sin (i3⁄4t -T 2) |g [τ-T 2) g _match (t - τ)άτ

+ lg(TT _b /2)g _match (tT)s ( _ac (t-2T)-T _b /2)dT From equation (7), you can see the term f _g (r-7l/2)g {ί -τ) The peak time of άτ is delayed by 7; /2, so the sample point is in the "tail of the Gaussian wave, that is, the waveform of the Gaussian wave whose amplitude is close to 0, even if sin^t-2" is in Q The surrounding point of the demodulated signal (ie, the non-sampling point) is not equal to 0, and the lateral opening degree and the longitudinal opening degree are increased. It is understood that the modulated signal after the CAP modulation, It can be directly transmitted to the receiving end through the electrical channel, or can be transmitted to the receiving end through the optical channel after being modulated by the optical channel, which is not limited in this embodiment.

In this embodiment, by receiving the first input signal and the second input signal, the first input signal and the second input signal have the same phase, and then performing phase shift processing on the first input signal to generate a third An input signal, the third input signal being out of phase with the first input signal by an odd multiple of π, enabling CAP modulation of the third input signal and the second input signal, Since the two input signals subjected to CAP modulation have an odd multiple of π, the envelope signals of the two demodulated signals obtained by the demodulation can be separated, thereby reducing the demodulation of the two demodulated signals. Inter-code interference of the sample points to improve the reliability of the CAP modulation signal.

It should be noted that the eye diagrams provided in this embodiment are all modulated and demodulated by using a 4-level PAM-4 signal as an input signal (ie, a first input signal and a second input signal).

It should be noted that, for the foregoing method embodiments, for the sake of brevity, they are all described as a series of action combinations, but those skilled in the art should understand that the present application is not limited by the described action sequence. Because in accordance with the present application, certain steps may be performed in other orders or concurrently. In addition, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

In the above embodiments, the descriptions of the various embodiments are different, and the parts that are not detailed in a certain embodiment can be referred to the related descriptions of other embodiments.

FIG. 5 is a schematic structural diagram of a signal modulating device according to another embodiment of the present invention. As shown in FIG. 5, the signal modulating device of this embodiment may include a receiver 51, a phase shifter 52, and a signal modulator 53. The receiver 51 is configured to receive the first input signal and the second input signal, and transmit the first input signal to the phase shifter 52, and transmit the second input signal to the signal modulator 53, the An input signal is in the same phase as the second input signal; a phase shifter 52 is configured to perform phase shift processing on the first input signal, generate a third input signal, and transmit the third input signal to the signal modulation The third input signal is different from the phase of the first input signal by an odd multiple of π; the signal modulator 53 is configured to perform CAP modulation on the third input signal and the second input signal.

Optionally, in a possible implementation manner of this embodiment, the first input signal and the second input signal may be an NRZ signal, or may also be a PAM signal.

After the modulation device of the signal obtains the modulated signal, it is transmitted to the receiving end via the transmission channel, and demodulated by the receiving end, and the obtained two demodulated signals, that is, the in-phase (I) demodulated signal and quadrature (Quadrature, Q) ) Demodulation signal. Since the modulation device of the signal converts the first input signal into a third input signal with an odd multiple of phase difference π before performing CAP modulation, the intermodulation interference of the demodulated two demodulated signals at the non-sample point is reduced. Small, as shown in Figure 3. Compared with FIG. 2, the lateral opening degree of the eye diagram shown in FIG. 3 becomes larger, indicating that the inter-code interference of the two demodulated signals obtained by demodulation becomes smaller at the non-sample points. Optionally, in a possible implementation manner of the embodiment, the signal modulator 53 may specifically perform CAP modulation on the third input signal and the second input signal by using a filter with a lower frequency domain roll-off. For example, a Gaussian filter. Since the Gaussian filter has smaller jitter than the other filters (for example, the root raised cosine filter) at the position where the π phase difference is shifted, the two demodulated signals obtained by the demodulation can be inter-coded at the sample point. Reduced. Further, when the ΒΤ value is greater than or equal to 0.5, Β is the filter cutoff frequency, Τ is the symbol width, and the jitter of the Gaussian filter at the position where the π phase difference is moved is significantly reduced, so that the two-way solution obtained by the demodulation can be obtained. The intermodulation interference of the modulated signal at the sample point is significantly reduced. As shown in FIG. 4, compared with FIG. 3, the longitudinal opening degree of the eye pattern shown in FIG. 4 becomes larger, indicating that the two-way demodulated signals obtained by the demodulation become smaller in the inter-code interference of the sample points.

In this embodiment, the modulation device of the signal receives the first input signal and the second input signal through the receiver, where the first input signal and the second input signal have the same phase, and then the phase shifter pairs the first The input signal is subjected to phase shift processing to generate a third input signal, the third input signal being out of phase with the first input signal by an odd multiple of π, such that the signal modulator is capable of the third input signal and the The two input signals are CAP modulated. Since the two input signals subjected to CAP modulation have an odd multiple of π, the envelope signals of the two demodulated signals obtained by the demodulation can be separated, thereby reducing the demodulation. The two demodulated signals interfere with each other at the non-sampled point to improve the reliability of the CAP modulated signal.

FIG. 6 is a schematic structural diagram of a signal modulation apparatus according to another embodiment of the present application. As shown in FIG. 6, the signal modulation apparatus of this embodiment may include a receiver 61, a processor 62, and a signal modulator 63. The receiver 61 is configured to receive the first input signal and the second input signal, and transmit the first input signal to the processor 62, and transmit the second input signal to the signal modulator 63, the first The input signal is in the same phase as the second input signal; the processor 62 is configured to perform phase shift processing on the first input signal, generate a third input signal, and transmit the third input signal to the signal modulator 63. And the third input signal is different from the phase of the first input signal by an odd multiple of π; the signal modulator 63 is configured to perform CAP modulation on the third input signal and the second input signal.

After the modulation device of the signal obtains the modulated signal, it is transmitted to the receiving end via the transmission channel, and demodulated by the receiving end, and the obtained two demodulated signals, that is, the inphase (I) channel demodulated signal and Quadrature (Q) way to demodulate the signal. Since the modulation device of the signal converts the first input signal into a third input signal with an odd multiple of phase difference π before performing CAP modulation, the intermodulation interference of the demodulated two demodulated signals at the non-sample point is reduced. Small, as shown in Figure 3. Compared with FIG. 2, the lateral opening degree of the eye diagram shown in FIG. 3 becomes larger, indicating that the inter-code interference of the two demodulated signals obtained by demodulation becomes smaller at the non-sample points.

Optionally, in a possible implementation manner of the embodiment, the signal modulator 63 may specifically perform CAP modulation on the third input signal and the second input signal by using a filter with a lower frequency domain roll-off. For example, a Gaussian filter. Since the Gaussian filter has smaller jitter than the other filters (for example, the root raised cosine filter) at the position where the π phase difference is shifted, the two demodulated signals obtained by the demodulation can be inter-coded at the sample point. Reduced. Further, when the ΒΤ value is greater than or equal to 0.5, Β is the filter cutoff frequency, Τ is the symbol width, and the jitter of the Gaussian filter at the position where the π phase difference is moved is significantly reduced, so that the two-way solution obtained by the demodulation can be obtained. The intermodulation interference of the modulated signal at the sample point is significantly reduced. As shown in Fig. 4, compared with Fig. 3, the longitudinal opening degree of the eye pattern shown in Fig. 4 becomes larger, indicating that the two-way demodulated signals obtained by demodulation become smaller in the inter-code interference of the sample points.

Optionally, in a possible implementation manner of this embodiment, as shown in FIG. 7, the signal modulator

63. The CAP-modulated modulation signal may be further transmitted to the memory 71. The modulation device of the signal provided in this embodiment may further include a memory 71, for storing the modulation device in the modulation information embodiment. Receiving, by the receiver, the first input signal and the second input signal, wherein the first input signal and the second input signal have the same phase, and then the first input signal is phase-shifted by the processor to generate a third An input signal, the third input signal being out of phase with the first input signal by an odd multiple of π, such that the signal modulator is capable of CAP modulating the third input signal and the second input signal due to CAP The two input signals of the modulation have an odd multiple of π, so that the envelope signals of the two demodulated signals obtained by the demodulation can be separated, thereby reducing the demodulated two demodulated signals at the non-sampling points. Inter-code interference to improve the reliability of the CAP modulated signal.

A person skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, device and The method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one phase shifter, or each unit may exist physically separately, or two or more units may be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units.

The above-described integrated unit implemented in the form of a software functional unit can be stored in a computer readable storage medium. The above software functional unit is stored in a storage medium and includes a plurality of instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to execute the method of the various embodiments of the present application. Part of the steps. The foregoing storage medium includes: a U disk, a mobile hard disk, a Read-Only Memory (ROM), a random access memory (RAM), a disk or an optical disk, and the like, which can store program codes. .

Finally, it should be noted that the above embodiments are only used to explain the technical solutions of the present application, and are not limited thereto; although the present application is described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: The technical solutions described in the foregoing embodiments are modified, or some of the technical features are equivalently substituted; and the modifications or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

Claim

A method for modulating a signal, comprising:

The third input signal and the second input signal are CAP modulated.

2. The method of claim 1 wherein the first input signal and the second input signal comprise non-return to zero signals or pulse amplitude modulated signals.

The method according to claim 1 or 2, wherein the CAP modulating the third input signal and the second input signal comprises:

A modulation device for a signal, comprising:

The signal modulator is configured to perform CAP modulation on the third input signal and the second input signal.

5. Apparatus according to claim 4 wherein said first input signal and said second input signal comprise non-return to zero signals or pulse amplitude modulated signals.

The apparatus according to claim 4 or 5, wherein the signal modulator is specifically used for

7. A signal modulation device, comprising:

a receiver, configured to receive a first input signal and a second input signal, and to input the first input Transmitting the signal to the processor, transmitting the second input signal to the signal modulator, the first input signal and the second input signal having the same phase;

8. Apparatus according to claim 7 wherein said first input signal and said second input signal comprise non-return to zero signals or pulse amplitude modulated signals.

The device according to claim 7 or 8, wherein the signal modulator is specifically used for

10. The device according to any one of claims 7 to 9, wherein the signal modulator is further used for

Transmitting the modulated signal modulated by the CAP to a memory;

The device also includes a memory for storing the modulated signal.