CN111431836B - Method and system for constructing baseband waveform in 512-path subcarrier OFDM wireless communication - Google Patents

Abstract

The invention discloses a method and a system for constructing baseband waveform in 512-path subcarrier OFDM wireless communication, wherein the method converts serial data passing through a signal transmitting terminal S/P into parallel data, and obtains each path of real signal [ d ] ₁ ,d ₂ ,......d ₅₁₂ ]Respectively multiplying with SIN function in trigonometric function, and respectively multiplying the signal after channel transmission with SIN2 pi f _k t, multiplying different frequency multiplication values, and obtaining real signals [ d ] of each path in an integral demodulation mode ₁ ,d ₂ ,......d ₅₁₂ ](ii) a The baseband waveform obtained by the method greatly reduces the operation amount in the realization process of the system, so that the system is simpler to realize.

Description

Method and system for constructing baseband waveform in 512-path subcarrier OFDM wireless communication

Technical Field

The present invention relates to the field of communications, and in particular, to a method and a system for constructing baseband waveforms in 512-channel subcarrier OFDM wireless communications.

Background

At present, in the waveform formation of OFDM, a plurality of paths of complex signals are adopted, and the waveform superposition mode is adopted, so thatThe complexity of system construction is caused, and two paths of orthogonal series of COS and SIN need to be processed at the same time. As shown in fig. 2, if 512 paths of subcarrier signals need to be processed in the conventional manner, 512 paths of COS signals and 512 paths of SIN signals; in the course of signal processing sin2 π f _k t and cos2 π f _k t are only 90 degrees out of phase. Further, as k increases, the frequency increases, and a small time delay per unit time of a certain carrier may cause waveform distortion. Especially when multipath effect is encountered, the signal phase difference is more susceptible; and has a large amount of computation.

Disclosure of Invention

Aiming at the existing problems, the invention provides a method and a system for constructing a baseband waveform in 512-path subcarrier OFDM wireless communication.

The technical scheme provided by the invention is as follows:

on one hand, the method for constructing the baseband waveform in the 512-path subcarrier OFDM wireless communication is used for converting serial data passing through a signal transmitting terminal S/P into parallel data and obtaining each path of real signals [ d ₁ ,d ₂ ,........d ₅₁₂ ]Respectively multiplied with SIN function in trigonometric function, and respectively multiplied with SIN2 pi f _k t, multiplying by different frequency multiplication values, and obtaining each path of signal [ d ] by an integral demodulation mode ₁ ,d ₂ ,........d ₅₁₂ ]。

256 pairs of conjugate pair complex signals are converted into 512 paths of signals through IFFT.

Further, each path of signals [ d ] to be obtained ₁ ,d ₂ ,........d ₅₁₂ ]The multiplication with the SIN function in the trigonometric function respectively means:

f ₁ ＝15kHz；f _k ＝k*f ₁

wherein s is _(t) Representing respective signals [ d ] ₁ ,d ₂ ,........d ₅₁₂ ]Respectively multiplying with SIN function in trigonometric function to obtain signal, t represents time, and K has value range of [1, 256%]K has a value range of [1,512 ]]。

The signal mutation in the same code element period is located in the middle, so that enough time can be reserved for the PA, and the system is simpler and more convenient to realize.

In another aspect, a system for constructing a baseband waveform in 512-path subcarrier OFDM wireless communication includes:

the signal transmitting terminal S/P is used for transmitting signals;

the data conversion module is used for converting serial signal data transmitted by the signal transmitting terminal S/P into parallel signal data;

a signal extraction module for extracting 512-channel real signal values [ d ] of the data conversion module in the process of converting the signal data ₁ ,d ₂ ,........d ₅₁₂ ]；

The SIN function multiplying module multiplies the signal extracting module with the corresponding SIN function respectively;

sin2πf _k a t multiplication module for transmitting the signal obtained by the SIN function multiplication module with the channel and then mixing with SIN2 pi f _k t is multiplied correspondingly;

integral demodulation module for demodulating sin2 pi f _k Signals obtained by the t multiplication module are subjected to integral demodulation processing respectively;

the principle of integral demodulation is as follows:

original signal S (t) = d _k ·sin2πf _k t, demodulation: s (t) = d.sin 2 pi f _k t·s

S(t)·sin2πf _k t＝d _k ·sin2πf _k t·sin2πf _k t＝d _k ·(-0.5)·[cos(2πf _k t+2πf _k t)-cos(2πf _k t-2πf _k t)]，

High-pass filtering again to obtain [ d ] ₁ ,d ₂ ,........d ₅₁₂ ]And transmitting the receiving end P/S.

Furthermore, the SIN function multiplication module comprises two parts, one part is d _2K-1 ·sin2πf _2K-1 t, the other part is d _2K ·sin2πf _2K t, K is in the range of [1,256 ]]。

Advantageous effects

The invention provides a method and a system for constructing baseband waveform in 512-path subcarrier OFDM wireless communication ₁ ,d ₂ ,........d ₅₁₂ ]Respectively multiplied with SIN function in trigonometric function, and respectively multiplied with SIN2 pi f _k t, multiplying by different frequency multiplication values, and obtaining each path of signal [ d ] by an integral demodulation mode ₁ ,d ₂ ,........d ₅₁₂ ](ii) a The baseband waveform obtained by the method greatly reduces the operation amount in the realization process of the system, so that the system is simpler to realize.

Drawings

FIG. 1 is a schematic diagram of a system architecture provided by the present invention;

FIG. 2 is a schematic diagram of a conventional system architecture framework;

fig. 3 is a graph of the simulation results of waveforms obtained using an example of the present invention.

Detailed Description

In order to facilitate a better understanding of the present invention, reference is made to the following detailed description and accompanying drawings.

A method for constructing baseband waveform in 512-path subcarrier OFDM wireless communication is characterized in that when serial data passing through a signal transmitting terminal S/P is converted into parallel data, each path of real signal [ d ] is obtained ₁ ,d ₂ ,........d ₅₁₂ ]Respectively multiplied with SIN function in trigonometric function, and respectively multiplied with SIN2 pi f _k t, multiplying by different frequency multiplication values, and obtaining each path of signal [ d ] by an integral demodulation mode ₁ ,d ₂ ,........d ₅₁₂ ]。

The essence is that 256 paths of QAM modulated complex signals are conjugated to produce another 256 paths of complex signals, and the IFFT is carried out on the upper 2 paths of 256 complex signals at one time to obtain 512 paths of real signals.

The obtained signals [ d ] ₁ ,d ₂ ,........d ₅₁₂ ]The multiplication with the SIN function in the trigonometric function respectively means:

f ₁ ＝15kHz；f _k ＝k*f ₁

wherein s is _(t) Representing respective signals [ d ] ₁ ,d ₂ ,........d ₅₁₂ ]And (3) signals obtained by multiplying the SIN function in the trigonometric function respectively, wherein t represents time.

The result of the MATLAB simulation result oscillogram is shown in FIG. 3, and the signal mutation in the same code element period is located in the middle, so that enough time can be left for PA, and the system can be more conveniently realized.

It can be seen from the above figure that the high peak waveforms that were on both sides have shifted to the middle, thus leaving room for the PA and the system response. Allowing the theory of the system to become realistic. As for the pulse too high, the signal can be compressed at the transmitting end of the signal, and the receiving end can recover the signal. To implement the entire system. It is not overrepresented here.

As shown in fig. 1, a system for constructing a baseband waveform in 512-channel subcarrier OFDM wireless communication includes:

the signal transmitting terminal S/P is used for transmitting signals;

the data conversion module is used for converting serial signal data transmitted by the signal transmitting terminal S/P into parallel signal data;

a signal extraction module for extracting 512-channel real signal values [ d ] of the data conversion module in the process of converting the signal data ₁ ,d ₂ ,........d ₅₁₂ ]；

The SIN function multiplying module multiplies the signal extracting module with the corresponding SIN function respectively;

sin2πf _k a t multiplication module for transmitting the signal obtained by the SIN function multiplication module with the channel and then mixing with SIN2 pi f _k t is multiplied correspondingly;

integral demodulation module tosin2πf _k Signals obtained by the t multiplying module are subjected to integral demodulation processing respectively;

the principle of integral demodulation is as follows:

original signal S (t) = d _k ·sin2πf _k t, demodulation: s (t) = d.sin 2 pi f _k t·s

S(t)·sin2πf _k t＝d _k ·sin2πf _k t·sin2πf _k t＝d _k ·(-0.5)·[cos(2πf _k t+2πf _k t)-cos(2πf _k t-2πf _k t)]，

High-pass filtering again to obtain [ d ] ₁ ,d ₂ ,........d ₅₁₂ ]And transmitting the receiving end P/S.

The SIN function multiplication module comprises two parts, one part is d _2K-1 ·sin2πf _2K-1 t, the other part is d _2K ·sin2πf _2K t, K is in the range of [1,256%]。

The present invention is not limited to the above embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and scope of the present invention should be included.

Claims (2)

1. A construction method of a baseband waveform in 512-path subcarrier OFDM wireless communication is characterized in that when serial data passing through a signal transmitting terminal S/P is converted into parallel data, each path of real signals [ d ] is obtained ₁ ,d ₂ ,........d ₅₁₂ ]Respectively multiplied with SIN function in trigonometric function, and respectively multiplied with SIN2 pi f _k t, multiplying by different frequency multiplication values, and obtaining each path of signal [ d ] by an integral demodulation mode ₁ ,d ₂ ,........d ₅₁₂ ]；

Wherein, each path of signals [ d ] to be obtained ₁ ,d ₂ ,........d ₅₁₂ ]The multiplication with the SIN function in the trigonometric function respectively means:

f ₁ ＝15kHz；f _k ＝k*f ₁

wherein s is _(t) Representing respective signals [ d ] ₁ ,d ₂ ,........d ₅₁₂ ]Respectively multiplied with SIN function in trigonometric function to obtain signal, t represents time, and K has value range of [1, 256%]K has a value range of [1,512 ]]。

2. A system for constructing a baseband waveform for 512-channel subcarrier OFDM wireless communication, comprising:

the signal transmitting terminal S/P is used for transmitting signals;

the data conversion module is used for converting serial signal data transmitted by the signal transmitting terminal S/P into parallel signal data;

a signal extraction module for extracting 512-path real signal value [ d ] of the data conversion module in the process of converting the signal data ₁ ,d ₂ ,........d ₅₁₂ ]；

The SIN function multiplying module multiplies the signal extracting module with the corresponding SIN function respectively; the SIN function multiplication module comprises two parts, wherein one part is d _2K-1 ·sin2πf _2K-1 t, the other part is d _2K ·sin2πf _2K t, K is in the range of [1,256%]；

sin2πf _k A t multiplication module for transmitting the signal obtained by the SIN function multiplication module and SIN2 pi f _k t is multiplied correspondingly;

integral demodulation module for demodulating sin2 pi f _k Signals obtained by the t multiplying module are subjected to integral demodulation processing respectively;

the principle of integral demodulation is as follows:

original signal S (t) = d _k ·sin2πf _k t, demodulation: s (t) = d.sin 2 pi f _k t·s

S(t)·sin2πf _k t＝d _k ·sin2πf _k t·sin2πf _k t＝d _k ·(-0.5)·[cos(2πf _k t+2πf _k t)-cos(2πf _k t-2πf _k t)]Then, againAfter sub-high-pass filtering, respectively obtain [ d ₁ ,d ₂ ,........d ₅₁₂ ]And transmitting the receiving end P/S.

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