CN103095628B - A kind of launching technique, method of reseptance and device reducing out-of-band radiation - Google Patents

Abstract

The invention discloses a transmitting method, a receiving method and a device for reducing out-of-band radiation, belonging to the communication field. The method includes: dividing OFDM subcarriers into subcarrier pairs, each subcarrier pair comprising two adjacent OFDM subcarriers, and each OFDM subcarrier being divided into at most one subcarrier pair ; Each constellation symbol included in the data bit stream to be sent is mapped to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol through two complex weighting coefficients, so as to offset the two Out-of-band radiation generated by OFDM subcarriers; performing inverse fast Fourier transform on the mapped data bit stream to be sent, inserting a cyclic prefix to form an OFDM baseband signal, and transmitting the OFDM baseband signal. The device includes: a dividing module, a mapping module and a modulating module. The invention can reduce the complexity of operation.

Description

A transmitting method, receiving method and device for reducing out-of-band radiation

technical field

The invention relates to the communication field, in particular to a transmitting method, a receiving method and a device for reducing out-of-band radiation.

Background technique

OFDM (Orthogonal Frequency-Division Multiplexing, Orthogonal Frequency Division Multiplexing) technology has the advantages of strong wireless channel frequency selective fading suppression capability and high spectral efficiency, and can be easily realized by fast Fourier transform, and is widely used in DAB (DigitalAudioBroadcasting, Digital Audio Broadcasting), WiMax (Worldwide Interoperability for Microwave Access), LTE (Long-Term Evolution, long-term evolution) and other wireless terrestrial broadcasting and cellular communication systems.

However, OFDM technology has inherent disadvantages of strong out-of-band radiation, which will cause relatively large adjacent channel interference. Therefore, corresponding technical means are needed to reduce the impact of out-of-band radiation. At present, there is a technology for reducing out-of-band radiation at the transmitting end, specifically: assuming that the data block to be sent includes n constellation symbols, the transmitting end maps the n constellation symbols included in the data block to be sent to n OFDM sub- On the carrier, calculate the out-of-band radiation intensity generated by the mapped n OFDM subcarriers, calculate n coefficients or n-order matrices according to the calculated out-of-band radiation intensity, and each coefficient corresponds to a sub-carrier and each order matrix corresponds to a sub-carrier Carrier, multiply each coefficient with the constellation symbol on the subcarrier corresponding to each coefficient to reduce the out-of-band radiation generated by the n subcarriers; or, multiply each order matrix with the constellation symbol on the subcarrier corresponding to each order matrix Multiply to reduce the out-of-band radiation generated by the n subcarriers, and then form the n subcarriers into an OFDM baseband signal, and the out-of-band radiation of the OFDM baseband signal is reduced, and then transmit the OFDM baseband signal.

In the process of realizing the present invention, the inventor finds that there are at least the following problems in the prior art:

When the existing technology reduces the out-of-band radiation, it is necessary to calculate the out-of-band radiation intensity generated by the sub-carriers first, calculate the coefficients or matrices of all sub-carriers according to the calculated out-of-band radiation intensity, and then reduce the out-of-band radiation according to the calculated coefficients or matrices. Radiation, the complexity of calculation is high.

Contents of the invention

In order to reduce the complexity of calculation, the embodiment of the present invention provides a transmitting method, a receiving method and a device for reducing out-of-band radiation. Described technical scheme is as follows:

A method of emission that reduces out-of-band radiation, the method comprising:

Dividing orthogonal frequency division multiplexing OFDM subcarriers into subcarrier pairs, each subcarrier pair comprising two adjacent OFDM subcarriers, each OFDM subcarrier being divided into at most one subcarrier pair;

Each constellation symbol included in the data bit stream to be sent is mapped to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol through two complex weighting coefficients, so as to offset the two OFDM Out-of-band radiation generated by subcarriers;

Inverse Fast Fourier Transform is performed on the mapped data bit stream to be sent, and a cyclic prefix is inserted to form an OFDM baseband signal, and the OFDM baseband signal is transmitted.

A receiving method for reducing out-of-band radiation, the method comprising:

Receiving an OFDM baseband signal, removing the cyclic prefix in the OFDM baseband signal, and performing fast Fourier transform on the OFDM baseband signal to obtain each subcarrier pair included in the OFDM baseband signal;

Extracting two transmission symbols transmitted by each subcarrier pair from the two OFDM subcarriers included in each subcarrier pair;

Combining the two transmission symbols transmitted by each subcarrier pair to obtain one constellation symbol corresponding to each subcarrier pair.

A transmitting device for reducing out-of-band radiation, said device comprising:

A division module, configured to divide OFDM subcarriers into subcarrier pairs, each of which includes two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into at most one subcarrier pair ;

A mapping module, configured to map each constellation symbol included in the data bit stream to be sent to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol through two complex weighting coefficients, so as to offset Out-of-band radiation generated by the two OFDM subcarriers;

The modulation module is configured to perform inverse fast Fourier transform on the mapped data bit stream to be sent, insert a cyclic prefix to form an OFDM baseband signal, and transmit the OFDM baseband signal.

A receiving device for reducing out-of-band radiation, said device comprising:

The obtaining module is used to receive the OFDM baseband signal, remove the cyclic prefix in the OFDM baseband signal, and perform fast Fourier transform on the OFDM baseband signal to obtain each sub-band included in the OFDM baseband signal Carrier pair;

An extraction module, configured to extract two transmission symbols transmitted by each subcarrier pair from the two OFDM subcarriers included in each subcarrier pair;

A combining module, configured to combine the two transmission symbols transmitted by each subcarrier pair to obtain a constellation symbol corresponding to each subcarrier pair.

In the embodiment of the present invention, OFDM subcarriers are divided into subcarrier pairs, each subcarrier pair contains two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into at most one subcarrier pair, through the preset two A complex weighting coefficient maps each constellation symbol included in the data bit stream to be sent to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol, and reverses the mapped data bit stream to be sent Transforming to Fast Fourier and inserting a cyclic prefix to form an OFDM baseband signal, wherein each subcarrier pair includes two adjacent OFDM subcarriers, and each subcarrier pair includes two OFDM subcarriers that transmit the weighted same constellation symbol, The out-of-band radiation generated by the two OFDM sub-carriers included in each sub-carrier is offset, thus reducing the out-of-band radiation generated by the OFDM baseband signal, and when reducing the out-of-band radiation generated by the OFDM baseband signal, only the preset two A complex weighting coefficient maps the constellation symbol to the subcarrier pair corresponding to the constellation symbol, which greatly reduces the computational complexity.

Description of drawings

FIG. 1 is a flowchart of a transmission method for reducing out-of-band radiation provided by Embodiment 1 of the present invention;

FIG. 2 is a flow chart of a transmission method for reducing out-of-band radiation provided by Embodiment 2 of the present invention;

FIG. 3 is a schematic diagram of a subcarrier provided by Embodiment 2 of the present invention;

FIG. 4 is a subcarrier spectrum diagram provided by Embodiment 2 of the present invention;

FIG. 5 is a subcarrier power spectrum diagram provided by Embodiment 2 of the present invention;

FIG. 6 is a simulation diagram of a suppression effect provided by Embodiment 2 of the present invention;

FIG. 7 is a flowchart of a receiving method for recovering constellation symbols provided by Embodiment 3 of the present invention;

FIG. 8 is a flowchart of a receiving method for recovering constellation symbols provided by Embodiment 4 of the present invention;

FIG. 9 is a schematic diagram of a transmitting device for reducing out-of-band radiation provided by Embodiment 5 of the present invention;

Fig. 10 is a schematic diagram of a receiving apparatus for recovering constellation symbols provided by Embodiment 6 of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the implementation manner of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The method of each embodiment of the present invention is applied in a communication system that can communicate through OFDM, which can be wireless terrestrial broadcasting and cellular communication systems such as DAB, DVB-T, IEEE802.11a/g/n, WiMax, and LTE. The method may be executed by a communication base station or an access point or hotspot of a wireless local area network.

Example 1

As shown in Figure 1, an embodiment of the present invention provides a method for reducing out-of-band radiation emission, including:

Step 101: Divide OFDM subcarriers into subcarrier pairs, each subcarrier pair includes two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into at most one subcarrier pair;

Step 102: Map each constellation symbol included in the data bit stream to be sent to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol through two preset complex weighting coefficients to offset the two OFDM Out-of-band radiation generated by subcarriers;

Step 103: Perform IFFT (InverseFastFourierTransform, Inverse Fast Fourier Transform) transformation on the mapped data bit stream to be sent and insert CP (CyclicPrefix, cyclic prefix) to form an OFDM baseband signal, and transmit the formed OFDM baseband signal.

In the embodiment of the present invention, OFDM subcarriers are divided into subcarrier pairs, each subcarrier pair contains two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into at most one subcarrier pair, through the preset two A complex weighting coefficient maps each constellation symbol included in the data bit stream to be sent to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol, and performs IFFT on the mapped data bit stream to be sent Transform and insert CP to form an OFDM baseband signal, wherein each subcarrier pair includes two adjacent OFDM subcarriers, and the two OFDM subcarriers included in each subcarrier pair transmit the same constellation symbol that has been mapped, offsetting each subcarrier The out-of-band radiation signal generated by the two OFDM subcarriers included in the carrier pair reduces the out-of-band radiation generated by the OFDM baseband signal in this way, and when reducing the out-of-band radiation generated by the OFDM baseband signal, only two preset complex weights are required The coefficient maps the constellation symbol to the subcarrier pair corresponding to the constellation symbol, which greatly reduces the computational complexity.

Example 2

The embodiment of the present invention provides a transmission method for reducing out-of-band radiation. The transmission end uses the method provided in this embodiment to form an OFDM baseband signal and transmit the generated OFDM baseband signal. Referring to FIG. 2, the method includes:

Step 201: Encoding and modulating the data bit stream to be transmitted to obtain constellation symbols included in the data bit stream to be transmitted;

Assume that the data bit stream to be transmitted obtained by encoding and modulating the data bit stream to be transmitted includes K constellation symbols, and the K constellation symbols included in the data bit stream to be transmitted can be expressed as [s ₁ , s ₂ ,. . . , _sk ].

Step 202: Divide the OFDM subcarriers at the transmitting end into one or more subcarrier pairs, each subcarrier pair includes two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into at most one subcarrier pair;

Wherein, assuming that the OFDM modulated signal at the transmitting end includes N OFDM subcarriers, these OFDM subcarriers are divided to obtain M subcarrier pairs, and

Wherein, in this embodiment, the logarithm M of the divided subcarrier pairs may be greater than or equal to the number K of constellation symbols included in the data bit stream to be transmitted.

Step 203: Weight each constellation symbol included in the data bit stream to be transmitted by the preset two complex weighting coefficients to obtain the transmission symbol pair corresponding to each constellation symbol, and the two transmission symbols included in the transmission symbol pair correspond to the same Constellation symbols;

Specifically, for any constellation symbol included in the data bit stream to be sent, the constellation symbol is multiplied by the preset two complex weighting coefficients respectively to obtain two transmission symbols corresponding to the constellation symbol, and the constellation symbol corresponding to The two transmitted symbols form a transmitted symbol pair corresponding to the constellation symbol. For each other constellation symbol included in the data bit stream to be sent, the transmission symbol pair corresponding to each other constellation symbol included in the data bit stream to be sent is obtained by the same method as above.

Assume that the two preset complex weighting coefficients are a ₁ and a ₂ , and for any constellation symbol [s ₁ , s ₂ , ..., s _k ] included in the data bit stream to be sent, suppose is the constellation symbol s _k , the constellation symbol s _k is multiplied by two complex weighting coefficients a ₁ and a ₂ respectively to obtain the two transmitted symbols a ₁ s _k and a ₂ s _k corresponding to the constellation symbol s _k , and the constellation symbol s The two transmitted symbols a ₁ s _k and a ₂ s _k corresponding to _k form the transmitted symbol pair (a ₁ s _k , a ₂ s _k ) corresponding to the constellation symbol s _k , and for each other Constellation symbols respectively execute the same execution flow as constellation symbols _sk . Wherein, the data bit stream to be sent includes K constellation symbols, therefore K transmission symbol pairs are obtained after weighting the K constellation symbols included in the data bit stream to be sent respectively.

Wherein, it needs to be explained that: for any transmitted symbol pair, the two transmitted symbols included in the transmitted symbol pair carry the same constellation symbol, for example, for the transmitted symbol pair (a ₁ s _k , a ₂ s _k ), the The transmitted symbols a ₁ s _k and a ₂ s _k in the transmitted symbol pair (a ₁ s _k , a ₂ s _k ) carry the same constellation symbol s _k .

Wherein, the specific values of the two weight coefficients a ₁ and a ₂ may have multiple sets, for example, a ₁ may be set to be equal to +1, and a ₂ may be set to be equal to -1.

Step 204: Select a corresponding subcarrier pair for each constellation symbol included in the data bit stream to be sent;

For example, the data bit stream to be sent includes K constellation symbols respectively s ₁ , s ₂ , ..., _sk , and a corresponding subcarrier pair is selected for each constellation symbol from M subcarrier pairs, and different constellation symbols Corresponding to different subcarrier pairs, K subcarrier pairs are selected in this way.

Step 205: Map the transmission symbols included in the transmission symbol pair corresponding to each constellation symbol to the OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol, so as to cancel out-of-band radiation signals generated by the two OFDM subcarriers;

Specifically, for a transmission symbol pair corresponding to any constellation symbol, the two transmission symbols included in the transmission symbol pair corresponding to the constellation symbol are respectively mapped to two OFDM subcarriers included in the subcarrier pair corresponding to the constellation symbol; for The remaining transmit symbol pairs corresponding to each constellation symbol perform the same operation process as above, so that the transmit symbols included in the transmit symbol pair corresponding to each constellation symbol are mapped to the OFDM included in the subcarrier pair corresponding to each constellation symbol. on the subcarrier.

Wherein, referring to FIG. ₃ , the dots in FIG. ₃ represent subcarriers. For the constellation symbol _{s 1} , _{a 1 s 1} and a ₂ s ₁ are respectively mapped to the _two OFDM subcarriers included in the subcarrier pair corresponding to the constellation symbol s ₁ , and the transmission symbol pairs ( _{a 1 s 2} , a ₂ s ₂ )...(a ₁ s _k , a ₂ s _k ) are mapped to the subcarrier pairs corresponding to constellation symbols s ₂ ...... s _k in the same way as above. on OFDM subcarriers.

Wherein, the two transmission symbols included in the transmission symbol pair corresponding to each constellation symbol are mapped to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol, and the transmission symbol pair corresponding to each constellation symbol includes The two transmitted symbols of the carry weighted same constellation symbols; while the two OFDM subcarriers included in the subcarrier pair are two adjacent OFDM subcarriers, by setting appropriate complex weighting coefficients, each constellation symbol corresponds to The out-of-band radiation signals generated by the two OFDM sub-carriers included in the sub-carrier pair can cancel each other, so that the out-of-band radiation generated by the two OFDM sub-carriers included in each carrier pair can be reduced.

Wherein, referring to Fig. 4, the amplitude diagram of two individual OFDM subcarriers included in a subcarrier pair in Fig. 4, the amplitude spectra of the two individual OFDM subcarriers in the subcarrier pair are respectively the two dotted lines in Fig. 4 Spectrum, the combined amplitude spectrum of two OFDM adjacent subcarriers in the subcarrier pair without weighting (it can also be considered that both weighting coefficients are 1) is the solid line spectrum in Fig. 4; see Fig. 5, in Fig. 5 The power spectrum diagram of two separate OFDM subcarriers included in a subcarrier pair, the power spectrum of the two separate OFDM subcarriers is the dotted line spectrum in Figure 5, and the two OFDM subcarriers in the subcarrier pair are not weighted (also It can be considered that the combined power spectrum with two weighting coefficients of 1) is the solid line spectrum in Fig. 5. It can be seen from Fig. 4 and 5 that the out-of-band radiation signal generated by two adjacent OFDM subcarriers included in the subcarrier pair has Possibility of mutual cancellation, which reduces the out-of-band radiation produced by the two OFDM subcarriers in a subcarrier pair.

Step 206: If there are remaining unselected subcarrier pairs, map preset values to the remaining unselected subcarrier pairs;

Wherein, the preset value may be 0, and in this embodiment, the specific value of the preset value is not limited.

For example, in this embodiment, the data bit stream to be sent includes K constellation symbols, so the number of subcarrier pairs selected is K, and the remaining unselected subcarrier pairs are M-K. If the value of M-K is not is zero, that is, there are still unselected subcarrier pairs, then for the remaining M-K subcarrier pairs, a preset value is mapped to the two OFDM subcarriers included in each subcarrier pair.

Step 207: Perform IFFT transformation on the mapped data bit stream to be sent and insert the CP to form an OFDM baseband signal, and transmit the formed OFDM baseband signal.

Wherein, the transmitting end may send the formed OFDM baseband signal to the receiving end through a channel between the transmitting end and the receiving end.

Wherein, Fig. 6 is the suppression effect emulation diagram that adopts the method that this embodiment provides to obtain, and dotted line among Fig. 6 is the spectrum mask (SpectrumMask) defined by 3GPP (ThirdGenerationPartnershipProject, the third generation partnership project) LTE standard, i.e. OFDM baseband signal The out-of-band radiation that produces can not be higher than this spectrum template, and the solid line in Fig. 6 is the spectrum of the out-of-band radiation that the OFDM baseband signal that adopts the method that this embodiment provides to form produces, as can be seen from Fig. 6 adopts the spectrum that this embodiment provides The method can make the out-of-band radiation generated by the OFDM baseband signal lower than the spectrum mask, and meet the requirements stipulated in the standard.

In the embodiment of the present invention, the data bit stream to be sent is encoded and modulated to obtain the constellation symbols included in the data bit stream to be sent, and the OFDM subcarriers are divided into subcarrier pairs, each subcarrier pair includes two adjacent OFDM subcarriers carrier, each OFDM subcarrier is divided into at most one subcarrier pair, and each constellation symbol included in the data bit stream to be sent is mapped to two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol, Perform IFFT transformation on the mapped data bit stream to be sent and insert CP to form an OFDM baseband signal, wherein each subcarrier pair includes two adjacent OFDM subcarriers, and each subcarrier pair includes two OFDM subcarriers The same weighted constellation symbol is transmitted, thereby offsetting the out-of-band radiation signal generated by the two OFDM sub-carriers included in each sub-carrier, thus reducing the out-of-band radiation generated by the formed OFDM baseband signal, and reducing the formed OFDM baseband signal At this time, it is only necessary to map the constellation symbol to the subcarrier pair corresponding to the constellation symbol through the preset two complex weighting coefficients, which greatly reduces the computational complexity.

Example 3

As shown in FIG. 7, an embodiment of the present invention provides a receiving method for reducing out-of-band radiation. The method receives the OFDM baseband signal sent by Embodiment 1, including:

Step 301: receive the OFDM baseband signal, remove the CP in the OFDM baseband signal, and perform FFT (FastFourierTransformation, Fast Fourier Transformation) transformation on the OFDM baseband signal to obtain each subcarrier pair included in the OFDM baseband signal;

Step 302: extracting two transmission symbols transmitted by each subcarrier pair from the two OFDM subcarriers included in each subcarrier pair;

Step 303: Combine the two transmission symbols transmitted by each subcarrier pair to obtain a constellation symbol corresponding to each subcarrier pair.

In the embodiment of the present invention, the OFDM baseband signal is received, each subcarrier pair included in the OFDM baseband signal is obtained, two transmit symbols transmitted by each subcarrier pair are extracted from the two OFDM subcarriers included in each subcarrier pair, and each One constellation symbol corresponding to each subcarrier pair is obtained from the two transmission symbols transmitted by subcarrier pairs, so that the constellation symbols included in the data bit stream sent by the sending end are recovered from the OFDM baseband signal.

Example 4

An embodiment of the present invention provides a receiving method for reducing out-of-band radiation, wherein, in Embodiment 2, the transmitting end forms an OFDM baseband signal, and sends the formed OFDM baseband signal to the receiving end through a channel between itself and the receiving end. At the receiving end, after receiving the OFDM baseband signal, the receiving end uses the method provided in this embodiment to restore the constellation symbols from the OFDM baseband signal. Referring to FIG. 8, the method includes:

Step 401: Receive the OFDM baseband signal, remove the CP in the received OFDM baseband signal, and then perform FFT transformation on the OFDM baseband signal to obtain all subcarrier pairs, and the subcarrier pairs include two OFDM subcarriers;

Wherein, there is one received signal on each OFDM subcarrier. At the receiving end, the received signals on the two OFDM subcarriers included in the kth subcarrier pair are y _2k-1 and y _2k respectively, and the received signals y _2k-1 and y _2k can be expressed by the following formula (1) .

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}\end{array}\right.<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, in the formula (1), h _2k-1 is the channel coefficient corresponding to the received signal y _2k-1 , n _2k-1 is the noise corresponding to the received signal y _2k-1 , and a ₁ is the noise corresponding to the received signal y _2k-1 Complex weighting coefficient; h _2k is the channel coefficient corresponding to the received signal y _2k , n _2k is the noise corresponding to the received signal y _2k , and a ₂ is the complex weighting coefficient corresponding to the received signal y _2k .

Step 402: Extracting two transmission symbols transmitted by each subcarrier pair from the two OFDM subcarriers included in each subcarrier pair;

Specifically, for any subcarrier pair, the subcarrier pair includes two OFDM subcarriers, and for one of the OFDM subcarriers, a transmit symbol transmitted by the OFDM subcarrier is extracted from the received signal on the OFDM subcarrier, from A transmit symbol transmitted by another OFDM subcarrier is extracted from a received signal on another OFDM subcarrier. For each other subcarrier pair, extract two transmission symbols transmitted by each other subcarrier pair by the same method as above.

Wherein, the transmitted symbol of the subcarrier transmission can be extracted from the received signal on the subcarrier by signal detection, and the signal detection includes MMSE (Minimum Mean Square Error) detection as shown in formula (2) and the detection as shown in formula (3) The ZF (Zero-forcing, zero-forcing) detection shown.

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; mmse</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}^{<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; the\; y</span>}}{{<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; ha</span>}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; zf</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}^{<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; the\; y</span>}}{{<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; ha</span>}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

Among them, in formulas (2) and (3), s is the transmitted symbol, y is the received signal, h is the channel coefficient corresponding to the received signal y, a is the complex weighting coefficient corresponding to the received signal y, and * represents the complex conjugate operation, σ ² is noise variance.

For example, for the kth subcarrier pair, the subcarrier pair includes two OFDM subcarriers, wherein the received signal on one OFDM subcarrier is y _2k-1 , and the received signal on the other OFDM subcarrier is y _2k .

From the received signal y _2k-1 on one of the OFDM subcarriers, the transmitted symbol s _k1 transmitted by the OFDM subcarrier is extracted through MMSE detection, and the extracted transmitted symbol s _k1 is shown in formula (4); or, from the OFDM From the received signal y _2k-1 on the subcarrier, the transmitted symbol s _k1 transmitted by the OFDM subcarrier is extracted through ZF detection, and the extracted transmitted symbol s _k1 is shown in formula (5).

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Wherein, in formulas (4) and (5), h _2k-1 is the channel coefficient corresponding to the received signal y _2k-1 , and a ₁ is the complex weighting coefficient corresponding to the received signal y _2k-1 .

From the received signal y _2k on another OFDM subcarrier, the transmitted symbol s _k2 transmitted by another OFDM subcarrier is extracted through MMSE detection, and the extracted transmitted symbol s _k2 is shown in formula (6); or, from another OFDM The transmitted symbol _sk2 transmitted by another OFDM subcarrier is extracted through ZF detection from the received signal y _2k on the subcarrier, and the extracted transmitted symbol _sk2 is shown in formula (7).

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Wherein, in formulas (6) and (7), a ₂ is the complex weighting coefficient corresponding to the received signal y _2k , and h _2k is the channel coefficient corresponding to the received signal y _2k .

In this way, the two transmission symbols s _k1 and s _2k transmitted by the kth subcarrier pair are extracted from the two OFDM subcarriers included in the kth subcarrier pair.

Step 403: Combining the two transmission symbols transmitted by each subcarrier pair to obtain a constellation symbol corresponding to each subcarrier pair.

Specifically, two transmission symbols transmitted by each subcarrier pair are normalized and added to obtain a constellation symbol corresponding to each subcarrier pair.

Wherein, the two transmission symbols transmitted by the subcarrier pair can be normalized and added by the following formula (8) to obtain a constellation symbol corresponding to the subcarrier pair,

$\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

Among them, in formula (8) is the constellation symbol corresponding to the subcarrier pair, and s ₁ and s ₂ are the two transmission symbols transmitted by the subcarrier pair.

For example, the two transmission symbols transmitted by the kth subcarrier pair are normalized and added according to the following method (8-1) or (8-2), to obtain the kth subcarrier pair corresponding to the formula (8-1) zodiac sign shown or the constellation notation as shown in Equation (8-2)

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \{</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \{</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span>$

Wherein, decoding and demodulating each subcarrier pair corresponding to a constellation symbol can obtain the data bit stream sent by the sending end.

Wherein, in this embodiment, a constellation symbol corresponding to each subcarrier pair obtained after combination will generate a certain amount of signal-to-noise ratio gain, and the order of the constellation symbol can be increased by using the signal-to-noise ratio gain.

In the embodiment of the present invention, the OFDM baseband signal is received, each subcarrier pair included in the OFDM baseband signal is obtained, and two transmission symbols transmitted by each subcarrier pair are extracted from the two OFDM subcarriers included in each subcarrier pair, and combined A constellation symbol corresponding to each subcarrier pair is obtained from the two transmission symbols transmitted by each subcarrier pair, so that the constellation symbols included in the data bit stream sent by the sending end are recovered from the OFDM baseband signal.

Example 5

As shown in Figure 9, an embodiment of the present invention provides a transmitting device for reducing out-of-band radiation, which is applied to a communication system that can communicate through OFDM, which can be DAB, DVB-T, IEEE802.11a/g/n , WiMax, LTE and other wireless terrestrial broadcasting and cellular communication systems. Devices to reduce out-of-band emissions include:

A dividing module 501, configured to divide OFDM subcarriers into subcarrier pairs, each subcarrier pair includes two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into at most one subcarrier pair;

The mapping module 502 is configured to map each constellation symbol included in the data bit stream to be sent to the two OFDM subcarriers included in the subcarrier pair corresponding to each constellation symbol through two preset complex weighting coefficients, To offset the out-of-band radiation generated by the two OFDM subcarriers;

The modulation module 503 is configured to perform inverse fast Fourier transform on the mapped data bit stream to be transmitted, insert a cyclic prefix to form an OFDM baseband signal, and transmit the formed OFDM baseband signal.

Wherein, the mapping module 502 includes:

The weighting unit is used to weight each constellation symbol included in the data bit stream to be transmitted by using two preset complex weighting coefficients to obtain a transmission symbol pair corresponding to each constellation symbol, and the transmission symbol pair includes two transmission symbols;

The first mapping unit is configured to select a corresponding subcarrier pair for each constellation symbol, and map the two transmission symbols included in the transmission symbol pair corresponding to each constellation symbol to the two subcarrier pairs included in each constellation symbol. in OFDM subcarriers.

Wherein, the weighting unit is specifically used to multiply each constellation symbol by two preset complex weighting coefficients to obtain two transmission symbols corresponding to each constellation symbol, and form the two transmission symbols corresponding to each constellation symbol into each The transmitted symbol pairs corresponding to the constellation symbols.

Further, the mapping module 502 also includes:

The second mapping unit is configured to, if there is an unselected subcarrier pair, map a preset value to subcarriers included in the unselected subcarrier pair.

Wherein, the two complex weighting coefficients may be +1 and -1 respectively.

In the embodiment of the present invention, OFDM subcarriers are divided into subcarrier pairs, each subcarrier pair contains two adjacent OFDM subcarriers, each OFDM subcarrier is divided into at most one subcarrier pair, and the data to be sent Each constellation symbol included in the bit stream is mapped to the two OFDM sub-carriers included in the subcarrier pair corresponding to each constellation symbol, and the mapped data bit stream to be transmitted is subjected to IFFT transformation and inserted into the CP to form an OFDM baseband signal. Among them, each subcarrier pair includes two adjacent OFDM subcarriers, and the two OFDM subcarriers included in each subcarrier pair transmit the same weighted constellation symbol, thereby offsetting the two OFDM subcarriers included in each subcarrier pair The generated out-of-band radiation signal, thus reducing the out-of-band radiation generated by the formed OFDM baseband signal, thus reducing the out-of-band radiation generated by the formed OFDM baseband signal, and only need to pass the preset two The complex weighting coefficient maps the constellation symbol to the subcarrier pair corresponding to the constellation symbol, which greatly reduces the computational complexity.

Example 6

As shown in Figure 10, an embodiment of the present invention provides a receiving device for reducing out-of-band radiation, which recovers constellation symbols from the OFDM baseband signal formed in Embodiment 5, including:

The obtaining module 601 is used to receive the OFDM baseband signal, remove the cyclic prefix in the OFDM baseband signal, and perform fast Fourier transform on the OFDM baseband signal to obtain each subcarrier pair included in the OFDM baseband signal;

An extraction module 602, configured to extract two transmission symbols transmitted by each subcarrier pair from the two OFDM subcarriers included in each subcarrier pair;

The combining module 603 is configured to combine two transmission symbols transmitted by each subcarrier pair to obtain a constellation symbol corresponding to each subcarrier pair.

Wherein, the merging module 603 is specifically configured to normalize and add two transmission symbols transmitted by each subcarrier pair to obtain a constellation symbol corresponding to each subcarrier pair.

Wherein, the merging module 603 is specifically configured to normalize and add the two transmission symbols transmitted by each subcarrier pair to obtain a constellation symbol corresponding to each subcarrier pair through the following formula (1),

$\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

Among them, in formula (1) is the constellation symbol corresponding to the subcarrier pair, and s ₁ and s ₂ are the two transmission symbols transmitted by the subcarrier pair.

In the embodiment of the present invention, the OFDM baseband signal is received, each subcarrier pair included in the OFDM baseband signal is obtained, and two transmission symbols transmitted by each subcarrier pair are extracted from the two OFDM subcarriers included in each subcarrier pair, and the normalized The two transmission symbols transmitted by each subcarrier pair are summed together to obtain a constellation symbol corresponding to each subcarrier pair, and thus the constellation symbol included in the data bit stream sent by the sending end is recovered from the OFDM baseband signal.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above embodiments can be completed by hardware, and can also be completed by instructing related hardware through a program. The program can be stored in a computer-readable storage medium. The above-mentioned The storage medium mentioned may be a read-only memory, a magnetic disk or an optical disk, and the like.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (12)

1. reduce a launching technique for out-of-band radiation, it is characterized in that, described method comprises:

Orthogonal frequency division multiplex OFDM subcarrier is divided into subcarrier pair, and described each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into a subcarrier centering at the most;

On two OFDM subcarriers that each constellation symbol mapped comprised by data bit flow to be sent by two complex weighting coefficients is comprised to the described subcarrier pair that described each constellation symbol is corresponding, to offset the out-of-band radiation that described two OFDM subcarriers produce;

Carry out inverse FFT to the data bit flow described to be sent after mapping and insert Cyclic Prefix forming OFDM baseband signal, launch described OFDM baseband signal;

Wherein, on two OFDM subcarriers that described each constellation symbol mapped of being comprised by data bit flow to be sent of two complex weighting coefficients by presetting comprises to the subcarrier pair that described each constellation symbol is corresponding, comprising:

Be weighted each constellation symbol that described data bit flow to be sent comprises by two complex weighting coefficients preset, obtain the transmitting symbol pair that described each constellation symbol is corresponding, described transmitting symbol launches symbol to comprising two;

For described each constellation symbol selects corresponding subcarrier pair, transmitting symbol corresponding for described each constellation symbol is launched on two OFDM subcarriers that sign map comprise to the subcarrier pair that described each constellation symbol is corresponding comprise two.

2. the method for claim 1, is characterized in that, described two complex weighting coefficients by presetting are weighted each constellation symbol that described data bit flow to be sent comprises, and obtain the transmitting symbol pair that described each constellation symbol is corresponding, comprising:

Described each constellation symbol is multiplied with described two default complex weighting coefficients respectively and obtains corresponding two of described each constellation symbol and launch symbol, corresponding for described each constellation symbol two are launched the transmitting symbol pair that the described each constellation symbol of symbols composition is corresponding.

3. the method for claim 1, is characterized in that, described is, after described each constellation symbol selects corresponding subcarrier pair, also comprise:

If there is unselected subcarrier pair, then map default numerical value in the subcarrier comprised to described unselected subcarrier pair.

4. the method as described in any one of claim 1-3 claim, is characterized in that, described two complex weighting coefficients are respectively+1 and-1.

5. reduce a method of reseptance for out-of-band radiation, it is characterized in that, described method comprises:

Receive orthogonal frequency division multiplex OFDM baseband signal, remove the Cyclic Prefix in described OFDM baseband signal, and fast Fourier transform is carried out to described OFDM baseband signal obtain each subcarrier pair that described OFDM baseband signal comprises;

Launch symbol for from two OFDM subcarriers that described each subcarrier pair comprises, extract described each subcarrier pair transmission two;

Merge described every height to carry and launch symbols to two of transmission and obtain described every height and carry a constellation symbol to correspondence;

Wherein, the described every height of described merging carries to be launched symbols to two of transmission and obtains described every height and carry a constellation symbol to correspondence, comprising:

Addition is normalized to two transmitting symbols of described each subcarrier pair transmission, obtains the constellation symbol that described each subcarrier pair is corresponding.

6. method as claimed in claim 5, is characterized in that, the described every height of described merging carries to be launched symbols to two of transmission and obtain described every height and carry a constellation symbol to correspondence, comprising:

Be normalized to be added by two transmitting symbols of following formula (1) to described each subcarrier pair transmission and obtain a constellation symbol corresponding to described each subcarrier pair,

$\hat{s}=\frac{1}{\sqrt{2}}(s_1+s_2)\mathrm{......}\left(1\right);$

Wherein, in formula (1) for the constellation symbol that subcarrier pair is corresponding, s ₁and s ₂for two transmitting symbols that described subcarrier pair transmits.

7. reduce an emitter for out-of-band radiation, it is characterized in that, described device comprises:

Divide module, for orthogonal frequency division multiplex OFDM subcarrier is divided into subcarrier pair, described each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into a subcarrier centering at the most;

Mapping block, for two OFDM subcarriers that each constellation symbol mapped comprised by data bit flow to be sent by two complex weighting coefficients is comprised to the described subcarrier pair that described each constellation symbol is corresponding, to offset the out-of-band radiation that described two OFDM subcarriers produce;

Modulation module, forms OFDM baseband signal for carrying out inverse FFT to the data bit flow described to be sent after mapping and inserting Cyclic Prefix, launches described OFDM baseband signal;

Wherein, described mapping block comprises:

Weighted units, being weighted each constellation symbol that described data bit flow to be sent comprises for two complex weighting coefficients by presetting, obtaining the transmitting symbol pair that described each constellation symbol is corresponding, and described transmitting symbol launches symbol to comprising two;

First map unit, for selecting corresponding subcarrier pair for described each constellation symbol, transmitting symbol corresponding for described each constellation symbol is launched in two OFDM subcarriers that sign map comprise to the subcarrier pair that described each constellation symbol is corresponding comprise two.

8. device as claimed in claim 7, is characterized in that,

Described weighted units, obtain corresponding two of described each constellation symbol specifically for described each constellation symbol being multiplied with described two default complex weighting coefficients respectively and launch symbol, corresponding for described each constellation symbol two are launched the transmitting symbol pair that the described each constellation symbol of symbols composition is corresponding.

9. device as claimed in claim 8, it is characterized in that, described mapping block also comprises:

Second map unit, if for there is unselected subcarrier pair, then maps default numerical value in the subcarrier comprised to described unselected subcarrier pair.

10. the device as described in any one of claim 7-9 claim, is characterized in that, described two complex weighting coefficients are respectively+1 and-1.

11. 1 kinds of receiving systems reducing out-of-band radiation, it is characterized in that, described device comprises:

Obtaining module, for receiving orthogonal frequency division multiplex OFDM baseband signal, removing the Cyclic Prefix in described OFDM baseband signal, and fast Fourier transform is carried out to described OFDM baseband signal obtain each subcarrier pair that described OFDM baseband signal comprises;

Extraction module, launches symbols for two of extracting described each subcarrier pair transmission in two OFDM subcarriers comprising from described each subcarrier pair;

Merge module, carry and launch symbols to two of transmission for merging described every height and obtain described every height and carry a constellation symbol to correspondence;

Wherein, described merging module, specifically for being normalized addition to two transmitting symbols of described each subcarrier pair transmission, obtains the constellation symbol that described each subcarrier pair is corresponding.

12. devices as claimed in claim 11, is characterized in that,

Described merging module, obtains a constellation symbol corresponding to described each subcarrier pair specifically for being normalized to be added by two transmitting symbols of following formula (1) to described each subcarrier pair transmission,

$\hat{s}=\frac{1}{\sqrt{2}}(s_1+s_2)\mathrm{......}\left(1\right);$

Wherein, in formula (1) for the constellation symbol that subcarrier pair is corresponding, s ₁and s ₂for two transmitting symbols that described subcarrier pair transmits.