CN103095628A - Sending method, receiving method and device capable of lowering out-of-band radiation - Google Patents

Abstract

The invention discloses a sending method, a receiving method and a device capable of lowering out-of-band radiation, and belongs to the field of communication. The sending method and the receiving method comprise that an orthogonal frequency division multiplexing (OFDM) subcarrier is divided into subcarrier pairs, each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier can be divided at most into one subcarrier pair; two complex weighting coefficients are used for mapping each constellation symbol contained in a to-be-sent data bit stream to two OFDM subcarriers contained in the subcarrier pair corresponding to each constellation symbol, and out-of-band radiation generated by the two OFDM subcarriers is offset; reversed fast Fourier transformation is carried out to the mapped to-be-sent data bit stream, and a cyclic prefix is inserted in the to-be-sent data bit stream to form an OFDM baseband signal which is sent then. The device comprises a dividing module, a mapping module and a modulation module. By means of the sending method, the receiving method and the device, operation complexity can be reduced.

Description

A kind of launching technique, method of reseptance and device that reduces out-of-band radiation

Technical field

The present invention relates to the communications field, particularly a kind of launching technique, method of reseptance and device that reduces out-of-band radiation.

Background technology

OFDM (Orthogonal Frequency-Division Multiplexing, OFDM) technology has stronger wireless channel frequency selective fading inhibition ability and spectrum efficiency advantages of higher, can be realized simply by fast Fourier transform, be widely used in DAB (Digital Audio Broadcasting, digital audio broadcasting), WiMax (Worldwide Interoperability for Microwave Access, the worldwide interoperability for microwave access), LTE (Long-Term Evolution, Long Term Evolution) wireless terrestrial broadcasting and the cellular communication system such as.

But there is the stronger shortcoming of intrinsic out-of-band radiation in the OFDM technology, can cause larger monkey chatter, therefore, needs corresponding technological means to reduce the impact of out-of-band radiation.exist at present at transmitting terminal and have a technology that reduces out-of-band radiation, be specially: suppose that data block to be sent comprises n constellation symbol, n the constellation symbol that transmitting terminal comprises data block to be sent is mapped to respectively on n OFDM subcarrier, calculate the out-of-band radiation intensity that n OFDM subcarrier after shining upon produces, calculate n coefficient or n rank matrix according to the out-of-band radiation intensity of calculating, and the corresponding subcarrier of each coefficient and the corresponding subcarrier of every rank matrix, constellation symbol on the subcarrier that each coefficient is corresponding with each coefficient multiply by mutually and reduces the out-of-band radiation that this n subcarrier produces, perhaps, constellation symbol on the subcarrier that every rank matrix is corresponding with every rank matrix multiply by mutually and reduces the out-of-band radiation that this n subcarrier produces, then this n subcarrier formed the OFDM baseband signal, and the out-of-band radiation of this OFDM baseband signal is reduced, then this OFDM baseband signal is launched.

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

Prior art is when reducing out-of-band radiation, need to first calculate the out-of-band radiation intensity that institute's subcarrier produces, calculate coefficient or the matrix of all subcarriers according to the out-of-band radiation intensity of calculating, then reduce out-of-band radiation according to the coefficient or the matrix that calculate, the complexity of computing is higher.

Summary of the invention

In order to reduce the complexity of computing, the embodiment of the present invention provides a kind of launching technique, method of reseptance and device that reduces out-of-band radiation.Described technical scheme is as follows:

A kind of launching technique that reduces out-of-band radiation, described method comprises:

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

Form the OFDM baseband signal to carrying out inverse FFT through the data bit flow described to be sent after mapping and inserting Cyclic Prefix, launch described OFDM baseband signal.

A kind of method of reseptance that reduces out-of-band radiation, described method comprises:

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

Extract two emission symbols of described each subcarrier pair transmission from two OFDM subcarriers that described each subcarrier pair comprises;

Merging described every height carries two emission symbols to transmission and obtains described every height and carry a constellation symbol to correspondence.

A kind of emitter that reduces out-of-band radiation, described device comprises:

Divide module, be used for the 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, two OFDM subcarriers that each constellation symbol mapped that is used for by two complex weighting coefficients, data bit flow to be sent being comprised comprises to described subcarrier pair corresponding to described each constellation symbol, the out-of-band radiation that produces to offset described two OFDM subcarriers;

Modulation module is used for forming the OFDM baseband signal to carrying out inverse FFT through the data bit flow described to be sent after mapping and inserting Cyclic Prefix, launches described OFDM baseband signal.

A kind of receiving system that reduces out-of-band radiation, described device comprises:

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

Extraction module is used for extracting from two OFDM subcarriers that described each subcarrier pair comprises two emission symbols that described each subcarrier pair transmits;

Merge module, be used for merging described every height and carry two emission symbols to transmission and obtain described every height and carry a constellation symbol to correspondence.

in embodiments of the present invention, the OFDM subcarrier is divided into subcarrier pair, each subcarrier pair comprises two adjacent OFDM subcarriers, each OFDM subcarrier is divided into a subcarrier centering at the most, on two OFDM subcarriers that each constellation symbol mapped that data bit flow to be sent is comprised by two default complex weighting coefficients comprises to subcarrier pair corresponding to each constellation symbol, form the OFDM baseband signal to carrying out inverse fast fourier transformed through the data bit flow to be sent after mapping and inserting Cyclic Prefix, wherein, each subcarrier pair comprises two adjacent OFDM subcarriers, and two OFDM subcarrier transmission that each subcarrier pair comprises are through the same constellation symbol of weighting, offset the out-of-band radiation that two OFDM subcarriers that each subcarrier pair comprises produce, so reduce the out-of-band radiation that the OFDM baseband signal produces, and when reducing the out-of-band radiation of OFDM baseband signal generation, only need by two default complex weighting coefficients with constellation symbol mapped in subcarrier pair corresponding to this constellation symbol, decrease computation complexity.

Description of drawings

Fig. 1 is a kind of launching technique flow chart that reduces out-of-band radiation that the embodiment of the present invention 1 provides;

Fig. 2 is a kind of launching technique flow chart that reduces out-of-band radiation that the embodiment of the present invention 2 provides;

Fig. 3 is the sub-carrier schematic diagram that the embodiment of the present invention 2 provides;

Fig. 4 is a kind of subcarrier spectrum figure that the embodiment of the present invention 2 provides;

Fig. 5 is a kind of sub-carrier power spectrogram that the embodiment of the present invention 2 provides;

Fig. 6 is a kind of inhibition analogous diagram that the embodiment of the present invention 2 provides;

Fig. 7 is a kind of method of reseptance flow chart that recovers constellation symbol that the embodiment of the present invention 3 provides;

Fig. 8 is a kind of method of reseptance flow chart that recovers constellation symbol that the embodiment of the present invention 4 provides;

Fig. 9 is a kind of emitter schematic diagram that reduces out-of-band radiation that the embodiment of the present invention 5 provides;

Figure 10 is a kind of receiving system schematic diagram that recovers constellation symbol that the embodiment of the present invention 6 provides.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, embodiment of the present invention is described further in detail below in conjunction with accompanying drawing.

In the communication system that the method for various embodiments of the present invention is applied to communicate by the OFDM mode, can be wireless terrestrial broadcasting and the cellular communication systems such as DAB, DVB-T, IEEE 802.11a/g/n, WiMax, LTE.And what carry out the method can be the access point of communication base station or WLAN (wireless local area network) or focus etc.

Embodiment 1

As shown in Figure 1, the embodiment of the present invention provides a kind of launching technique that reduces out-of-band radiation, comprising:

Step 101: the OFDM subcarrier is divided into subcarrier pair, and each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into a subcarrier centering at the most;

Step 102: on two OFDM subcarriers that each constellation symbol mapped that will data bit flow to be sent comprises by two default complex weighting coefficients comprises to subcarrier pair corresponding to each constellation symbol, to offset the out-of-band radiation of two OFDM subcarriers generations;

Step 103: to carrying out IFFT (Inverse Fast Fourier Transform through the data bit flow to be sent after mapping, inverse fast fourier transformed) conversion and insert CP (Cyclic Prefix, Cyclic Prefix) form the OFDM baseband signal, the OFDM baseband signal that emission forms.

in embodiments of the present invention, the OFDM subcarrier is divided into subcarrier pair, each subcarrier pair comprises two adjacent OFDM subcarriers, each OFDM subcarrier is divided into a subcarrier centering at the most, on two OFDM subcarriers that each constellation symbol mapped that data bit flow to be sent is comprised by two default complex weighting coefficients comprises to subcarrier pair corresponding to each constellation symbol, form the OFDM baseband signal to carrying out the IFFT conversion through the data bit flow to be sent after mapping and inserting CP, wherein, each subcarrier pair comprises two adjacent OFDM subcarriers, and two OFDM subcarrier transmission that each subcarrier pair comprises are through the same constellation symbol of mapping, offset the out-of-band radiation signal that two OFDM subcarriers that each subcarrier pair comprises produce, so reduce the out-of-band radiation that the OFDM baseband signal produces, and when reducing the out-of-band radiation of OFDM baseband signal generation, only need by two default complex weighting coefficients with constellation symbol mapped in subcarrier pair corresponding to this constellation symbol, decrease computation complexity.

Embodiment 2

The embodiment of the present invention provides a kind of launching technique that reduces out-of-band radiation, and transmitting terminal utilizes the method that the present embodiment provides form the OFDM baseband signal and launch the OFDM baseband signal that produces, and referring to Fig. 2, the method comprises:

Step 201: encoding and modulate to sent data bit flow obtains the constellation symbol that data bit flow to be sent comprises;

Suppose, encoding and modulate the data bit flow to be sent that obtains to sent data bit flow comprises K constellation symbol, and K the constellation symbol that data bit flow to be sent comprises can be expressed as [s ₁, s ₂..., s _k].

Step 202: the OFDM subcarrier of transmitting terminal is divided into one or more subcarrier pairs, and each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into a subcarrier centering at the most;

Wherein, suppose that the ofdm modulation signal of transmitting terminal comprises N OFDM subcarrier, these OFDM subcarriers are divided obtained M subcarrier pair, and

Wherein, in the present embodiment, the number K of the constellation symbol that the logarithm M of the subcarrier pair that division obtains can comprise more than or equal to data bit flow to be sent.

Step 203: be weighted to sent each constellation symbol that data bit flow comprises by two default complex weighting coefficients, obtain emission symbol corresponding to each constellation symbol pair, two the emission symbol corresponding same constellation symbol of emission symbol to comprising;

Particularly, any constellation symbol that comprises for data bit flow to be sent, this constellation symbol is obtained two emission symbols corresponding to this constellation symbol with default two complex weighting multiplication respectively, and two emission symbols that this constellation symbol is corresponding form emission symbol corresponding to this constellation symbol pair.Other each constellation symbol that comprise for data bit flow to be sent obtain emission symbol corresponding to other each constellation symbol that data bit flow to be sent comprises pair by above-mentioned identical method.

Suppose, two complex weighting coefficients that set in advance are a ₁And a ₂, the constellation symbol [s that comprises for data bit flow to be sent ₁, s ₂..., s _k] in any constellation symbol, be assumed to be constellation symbol s _k, with constellation symbol s _kRespectively with two complex weighting coefficient a ₁And a ₂Multiply each other and obtain constellation symbol s _kTwo corresponding emission symbol a ₁s _kAnd a ₂s _k, with constellation symbol s _kTwo corresponding emission symbol a ₁s _kAnd a ₂s _kForm constellation symbol s _kCorresponding emission symbol is to (a ₁s _k, a ₂s _k), carry out respectively and constellation symbol s for other each constellation symbol that data bit flow to be sent comprises _kIdentical execution flow process.Wherein, data bit flow to be sent comprises K constellation symbol, obtains K after K the constellation symbol that therefore comprises to sent data bit flow respectively is weighted and launches symbol pair.

Wherein, need to be in explanation be: any emission symbol pair, two the same constellation symbol that emission symbol carry of this emission symbol to comprising, for example, for launching symbol to (a ₁s _k, a ₂s _k), this emission symbol is to (a ₁s _k, a ₂s _k) in emission symbol a ₁s _kAnd a ₂s _kCarry identical constellation symbol s _k

Wherein, two weight coefficient a ₁And a ₂Concrete value many groups can be arranged, for example a can be set ₁Equal+1, a ₂Equal-1.

Step 204: for each constellation symbol that data bit flow to be sent comprises is selected a corresponding subcarrier pair;

For example, data bit flow to be sent comprises that K constellation symbol is respectively s ₁, s ₂..., s _k, select a corresponding subcarrier pair from M subcarrier centering for each constellation symbol, the subcarrier pair that the various constellations symbol is corresponding different has so been selected K subcarrier pair.

Step 205: on the OFDM subcarrier that the emission symbol that each constellation symbol is corresponding comprises to subcarrier pair corresponding to each constellation symbol the emission sign map that comprises, the out-of-band radiation signal that produces to offset these two OFDM subcarriers;

Particularly, for emission symbol corresponding to any constellation symbol pair, the emission symbol that this constellation symbol is corresponding is mapped to respectively on two OFDM subcarriers that subcarrier pair corresponding to this constellation symbol comprise two emission symbols that comprise; , so realize on OFDM subcarrier that the emission symbol that each constellation symbol is corresponding comprises to subcarrier pair corresponding to each constellation symbol the emission sign map that comprises carrying out above-mentioned identical operating process for emission symbol corresponding to each remaining constellation symbol.

Wherein, referring to Fig. 3, the round dot in Fig. 3 represents subcarrier, for constellation symbol s ₁, with constellation symbol s ₁Corresponding emission symbol is to (a ₁s ₁, a ₂s ₁) a that comprises ₁s ₁And a ₂s ₁Be mapped to respectively constellation symbol s ₁In two OFDM subcarriers that corresponding subcarrier pair comprises, with constellation symbol s ₂... s _kCorresponding emission symbol is to (a respectively ₁s ₂, a ₂s ₂) ... (a ₁s _k, a ₂s _k) all be mapped to respectively constellation symbol s by above-mentioned identical method ₂... s _kOn the OFDM subcarrier that corresponding subcarrier pair comprises respectively.

Wherein, in two OFDM subcarriers that comprise two emission sign map of the emission symbol centering that each constellation symbol is corresponding comprise to subcarrier pair corresponding to each constellation symbol, and emission symbol corresponding to each constellation symbol carries identical constellation symbol through weighting to two emission symbols that comprise; And two OFDM subcarriers that subcarrier pair comprises are all two adjacent OFDM subcarriers, make the out-of-band radiation signal that two OFDM subcarriers that subcarrier pair corresponding to each constellation symbol comprise produce to cancel out each other by suitable complex weighting coefficient is set, thereby can reduce the out-of-band radiation that two OFDM subcarriers that each carrier wave centering comprises produce.

Wherein, referring to Fig. 4, the map of magnitudes of two independent OFDM subcarriers that subcarrier centering comprises in Fig. 4, the amplitude spectrum of two independent OFDM subcarriers in subcarrier pair is respectively two dotted line spectrums in Fig. 4, and the amplitude spectrum of the merging of two not weightings of OFDM adjacent sub-carrier in subcarrier pair (can think that also two weight coefficients are 1) is the solid line spectrum in Fig. 4; Referring to Fig. 5, the power spectrum chart of two independent OFDM subcarriers that subcarrier centering comprises in Fig. 5, the power spectrum of independent two OFDM subcarriers is all the dotted line spectrum in Fig. 5, the merging power spectrum of two not weightings of OFDM subcarrier in subcarrier pair (can think that also two weight coefficients are 1) is the solid line spectrum in Fig. 5, from Figure 4 and 5 as can be known: the out-of-band radiation signal that two adjacent OFDM subcarriers that subcarrier pair comprises produce has the possibility of cancelling out each other, and so can reduce the out-of-band radiation that two OFDM subcarriers in subcarrier pair produce.

Step 206: if also there is remaining unselected subcarrier pair, shine upon default numerical value in remaining unselected subcarrier;

Wherein, default numerical value can be 0, in the present embodiment, the default concrete value of numerical value is not done restriction.

For example, in the present embodiment, data bit flow to be sent comprises K constellation symbol, the logarithm of the subcarrier pair of therefore selecting is K, remaining unselected subcarrier pair is M-K, if the value of M-K is non-vanishing, namely also has unselected subcarrier pair, for remaining M-K subcarrier pair, the default numerical value of mapping in two OFDM subcarriers that comprise to each subcarrier pair.

Step 207: form the OFDM baseband signal, the OFDM baseband signal that emission forms after will carrying out the IFFT conversion through the data bit flow to be sent after mapping and inserting CP.

Wherein, transmitting terminal can send to receiving terminal with the OFDM baseband signal that forms by the channel between transmitting terminal and receiving terminal.

wherein, Fig. 6 is the inhibition analogous diagram that adopts method that the present embodiment provides to obtain, in Fig. 6, dotted line is 3GPP (Third Generation Partnership Project, third generation partner program) the defined spectrum mask of LTE standard (Spectrum Mask), be that the out-of-band radiation that the OFDM baseband signal produces can not be higher than this spectrum mask, the frequency spectrum of the out-of-band radiation that the OFDM baseband signal that the method that in Fig. 6, solid line provides for employing the present embodiment forms produces, adopt as can be seen from Figure 6 the method that the present embodiment provides to make the out-of-band radiation of OFDM baseband signal generation lower than this spectrum mask, meet the requirement of prescribed by standard.

in embodiments of the present invention, encode and modulate to sent data bit flow and obtain the constellation symbol that data bit flow to be sent comprises, the OFDM subcarrier is divided into subcarrier pair, each subcarrier pair comprises two adjacent OFDM subcarriers, each OFDM subcarrier is divided into a subcarrier centering at the most, on two OFDM subcarriers that each constellation symbol mapped that data bit flow to be sent is comprised comprises to subcarrier pair corresponding to each constellation symbol, form the OFDM baseband signal to carrying out the IFFT conversion through the data bit flow to be sent after mapping and inserting CP, wherein, each subcarrier pair comprises two adjacent OFDM subcarriers, and two OFDM subcarrier transmission that each subcarrier pair comprises are through the same constellation symbol of weighting, thereby offset the out-of-band radiation signal that two OFDM subcarriers that each subcarrier pair comprises produce, so reduce the out-of-band radiation of the OFDM baseband signal generation that forms, and when the OFDM baseband signal that reduce to form only need to by two default complex weighting coefficients with constellation symbol mapped in subcarrier pair corresponding to this constellation symbol, decrease computation complexity.

Embodiment 3

As shown in Figure 7, the embodiment of the present invention provides a kind of method of reseptance that reduces out-of-band radiation, and the method receives the OFDM baseband signal that embodiment 1 sends, and comprising:

Step 301: receive the OFDM baseband signal, remove the CP in the OFDM baseband signal, and this OFDM baseband signal is carried out FFT (Fast Fourier Transformation, fast Fourier transform) conversion obtain each subcarrier pair that this OFDM baseband signal comprises;

Step 302: two emission symbols that extract each subcarrier pair transmission from two OFDM subcarriers that each subcarrier pair comprises;

Step 303: merge every height and carry two emission symbols to transmission and obtain every height and carry a constellation symbol to correspondence.

In embodiments of the present invention, receive the OFDM baseband signal, obtain each subcarrier pair that the OFDM baseband signal comprises, extract two emission symbols of each subcarrier pair transmission from two OFDM subcarriers that each subcarrier pair comprises, two emission symbols that merge each subcarrier pair transmission obtain a constellation symbol corresponding to each subcarrier pair, the constellation symbol that the data bit flow that recovers the transmitting terminal transmission from the OFDM baseband signal like this comprises.

Embodiment 4

The embodiment of the present invention provides a kind of method of reseptance that reduces out-of-band radiation, wherein, in embodiment 2, transmitting terminal forms the OFDM baseband signal, and by the channel between self and receiving terminal, the OFDM baseband signal that forms is sent to receiving terminal, receiving terminal utilizes the method that the present embodiment provides to recover constellation symbol from this OFDM baseband signal after receiving this OFDM baseband signal, and referring to Fig. 8, the method comprises:

Step 401: receive the OFDM baseband signal, remove the CP in the OFDM baseband signal that receives, then this OFDM baseband signal is carried out the FFT conversion obtain all subcarrier pairs, and subcarrier pair comprises two OFDM subcarriers;

Wherein, there is one to receive signal on each OFDM subcarrier.At receiving terminal, the reception signal on two OFDM subcarriers that k subcarrier centering comprises is respectively y _2k-1And y _2k, and receive signal y _2k-1And y _2kCan represent with following formula (1).

$\left\{\begin{array}{c}{y}_{2k-1}=h_{2k-1}{a}_1{s}_k+n_{2k-1}\\ y_{2k}=h_{2k}{a}_2{s}_k+n_{2k}\end{array}\right....\left(1\right)$

Wherein, h in formula (1) _2k-1For receiving signal y _2k-1Corresponding channel coefficients, n _2k-1For receiving signal y _2k-1Corresponding noise, a ₁For receiving signal y _2k-1Corresponding complex weighting coefficient; h _2kFor receiving signal y _2kCorresponding channel coefficients, n _2kFor receiving signal y _2kCorresponding noise, a ₂For receiving signal y _2kCorresponding complex weighting coefficient.

Step 402: two emission symbols that extract each subcarrier pair transmission from two OFDM subcarriers that each subcarrier pair comprises;

Particularly, for any subcarrier pair, this subcarrier pair comprises two OFDM subcarriers, for one of them OFDM subcarrier, extract an emission symbol of this OFDM subcarrier transmission reception signal from this OFDM subcarrier, extract an emission symbol of another OFDM subcarrier transmission the reception signal from another OFDM subcarrier.For other each subcarrier pairs, by above-mentioned identical method extract other every height carry to the transmission two the emission symbols.

Wherein, can extract by input the emission symbol of subcarrier transmission the reception signal from subcarrier, input comprises MMSE (the Minimum Mean Square Error as shown in formula (2), least mean-square error) detection and the ZF as shown in formula (3) (Zero-forcing, ZF) detect.

$s_{\mathrm{mmse}}=\frac{h^{*}{a}^{*}y}{{\left|\mathrm{ha}\right|}^2+{\mathrm{\σ}}^2}......\left(2\right);$

$s_{\mathrm{zf}}=\frac{h^{*}{a}^{*}y}{{\left|\mathrm{ha}\right|}^2}......\left(3\right);$

Wherein, s is the emission symbol in formula (2) and (3), and y is for receiving signal, and h is for receiving channel coefficients corresponding to signal y, and a is for receiving complex weighting coefficient corresponding to signal y, and * represents the complex conjugate computing, σ ²Be noise variance.

For example, for k subcarrier pair, this subcarrier pair comprises two OFDM subcarriers, and the reception signal on one of them OFDM subcarrier is y _2k-1, the reception signal on another OFDM subcarrier is y _2k

Reception signal y from one of them OFDM subcarrier _2k-1In emission symbol s by the transmission of this OFDM subcarrier of MMSE Detection and Extraction _k1, and the emission symbol s that extracts _k1As shown in formula (4); Perhaps, the reception signal y from this OFDM subcarrier _2k-1In emission symbol s by the transmission of this OFDM subcarrier of ZF Detection and Extraction _k1, and the emission symbol s that extracts _k1As shown in formula (5).

${\mathrm{<figure-callout\; id="1"\; label="s\; k"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">s</figure-callout>}}_k=\frac{h_{2k-1}^{*}{a}_1^{*}{y}_{2k-1}}{{\left|h_{2k-1}{a}_1\right|}^2+{\mathrm{\&sigma;}}^2}......\left(4\right);$

${\mathrm{<figure-callout\; id="1"\; label="s\; k"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">s</figure-callout>}}_k=\frac{h_{2k-1}^{*}{a}_1^{*}{y}_{2k-1}}{{\left|h_{2k-1}{a}_1\right|}^2}......\left(5\right)$

Wherein, h in formula (4) and (5) _2k-1For receiving signal y _2k-1Corresponding channel coefficients, a ₁For receiving signal y _2k-1Corresponding complex weighting coefficient.

Reception signal y from another OFDM subcarrier _2kIn emission symbol s by the transmission of another OFDM subcarrier of MMSE Detection and Extraction _k2, and the emission symbol s that extracts _k2As shown in formula (6); Perhaps, the reception signal y from another OFDM subcarrier _2kIn emission symbol s by the transmission of another OFDM subcarrier of ZF Detection and Extraction _k2, and the emission symbol s that extracts _k2As shown in formula (7).

${\mathrm{<figure-callout\; id="2"\; label="s\; k"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">s</figure-callout>}}_k=\frac{h_{2k}^{*}{a}_2^{*}{y}_{2k}}{{\left|h_{2k}{a}_2\right|}^2+{\mathrm{\&sigma;}}^2}......\left(6\right);$

${\mathrm{<figure-callout\; id="2"\; label="s\; k"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">s</figure-callout>}}_k=\frac{h_{2k}^{*}{a}_2^{*}{y}_{2k}}{{\left|h_{2k}{a}_2\right|}^2}......\left(7\right)$

Wherein, a in formula (6) and (7) ₂For receiving signal y _2kCorresponding complex weighting coefficient, h _2kFor receiving signal y _2kCorresponding channel coefficients.

So, just, extract two emission symbol s of k subcarrier pair transmission from two OFDM subcarriers that k subcarrier pair comprises _k1And s _2k

Step 403: two emission symbols that merge each subcarrier pair transmission obtain a constellation symbol corresponding to each subcarrier pair.

Particularly, two emission symbols that each subcarrier pair is transmitted carry out the normalization addition, obtain a constellation symbol corresponding to each subcarrier pair.

Wherein, can carry out the normalization addition by two emission symbols that following formula (8) transmits subcarrier pair and obtain a constellation symbol corresponding to this subcarrier pair,

$\hat{s}=\frac{1}{\sqrt{2}}({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">s</figure-callout>}}_1+s_2)......\left(8\right);$

Wherein, in formula (8)

Be constellation symbol corresponding to this subcarrier pair, s ₁And s ₂Two emission symbols for this subcarrier pair transmission.

For example, to two emission symbols of k subcarrier pair transmission (8-1) or (8-2) carry out the normalization addition in the following manner, obtain k son year to the constellation symbol as shown in formula (8-1) of correspondence

Or the constellation symbol as shown in formula (8-2)

${\hat{s}}_k=\frac{1}{\sqrt{2}}(s_{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">k</figure-callout>}1}+s_{k2})=\frac{1}{\sqrt{2}}\{\frac{h_{2k-1}^{*}{a}_1^{*}{y}_{2k-1}}{{\left|h_{2k-1}{a}_1\right|}^2+{\mathrm{\&sigma;}}^2}+\frac{h_{2k}^{*}{a}_2^{*}{y}_{2k}}{{\left|h_{2k}{a}_2\right|}^2+{\mathrm{\&sigma;}}^2}\}......(8-1);$

${\hat{s}}_k=\frac{1}{\sqrt{2}}(s_{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">k</figure-callout>}1}+s_{k2})=\frac{1}{\sqrt{2}}\{\frac{h_{2k-1}^{*}{a}_1^{*}{y}_{2k-1}}{{\left|h_{2k-1}{a}_1\right|}^2}+\frac{h_{2k}^{*}{a}_2^{*}{y}_{2k}}{{\left|h_{2k}{a}_2\right|}^2}\}......(8-2).$

Wherein, every height is carried a constellation symbol of correspondence is carried out decoding and demodulation process, can obtain the data bit flow that transmitting terminal sends.

Wherein, in the present embodiment, obtain a constellation symbol corresponding to each subcarrier pair after merging and can produce a certain amount of snr gain, can utilize this snr gain to improve the exponent number of constellation symbol.

In embodiments of the present invention, receive the OFDM baseband signal, obtain each subcarrier pair that this OFDM baseband signal comprises, carry extracting two emission symbols of each subcarrier pair transmission two OFDM subcarriers that comprise from every height, two emission symbols that merge each subcarrier pair transmission obtain a constellation symbol corresponding to each subcarrier pair, the constellation symbol that the data bit flow that recovers the transmitting terminal transmission from the OFDM baseband signal like this comprises.

Embodiment 5

As shown in Figure 9, the embodiment of the present invention provides a kind of emitter that reduces out-of-band radiation, in the communication system that is applied to communicate by the OFDM mode, can be wireless terrestrial broadcasting and the cellular communication systems such as DAB, DVB-T, IEEE 802.11a/g/n, WiMax, LTE.The device that reduces out-of-band radiation comprises:

Divide module 501, be used for the OFDM subcarrier is divided into subcarrier pair, each subcarrier pair comprises two adjacent OFDM subcarriers, and each OFDM subcarrier is divided into a subcarrier centering at the most;

Mapping block 502, for two OFDM subcarriers that each constellation symbol mapped that data bit flow to be sent is comprised by two default complex weighting coefficients comprises to subcarrier pair corresponding to described each constellation symbol, the out-of-band radiation that produces to offset described two OFDM subcarriers;

Modulation module 503 is used for forming the OFDM baseband signal, the OFDM baseband signal that emission forms to carrying out inverse FFT through the data bit flow described to be sent after mapping and inserting Cyclic Prefix.

Wherein, mapping block 502 comprises:

Weighted units is used for being weighted to sent each constellation symbol that data bit flow comprises by two default complex weighting coefficients, obtains emission symbol corresponding to each constellation symbol pair, and the emission symbol is to comprising two emission symbols;

The first map unit is used to each constellation symbol to select corresponding subcarrier pair, in two OFDM subcarriers that the emission symbol that each constellation symbol is corresponding comprises to subcarrier pair corresponding to each constellation symbol two emission sign map comprising.

Wherein, weighted units, concrete being used for obtains two emission symbols corresponding to each constellation symbol with default two complex weighting multiplication respectively with each constellation symbol, and two emission symbols that each constellation symbol is corresponding form emission symbol corresponding to each constellation symbol pair.

Further, mapping block 502 also comprises:

The second map unit, if be used for existing unselected subcarrier pair, the default numerical value of mapping in the subcarrier that comprises to unselected subcarrier pair.

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

in embodiments of the present invention, the OFDM subcarrier is divided into subcarrier pair, each subcarrier pair comprises two adjacent OFDM subcarriers, each OFDM subcarrier is divided into a subcarrier centering at the most, on two OFDM subcarriers that each constellation symbol mapped that data bit flow to be sent is comprised comprises to subcarrier pair corresponding to each constellation symbol, form the OFDM baseband signal to carrying out the IFFT conversion through the data bit flow to be sent after mapping and inserting CP, wherein, each subcarrier pair comprises two adjacent OFDM subcarriers, and two OFDM subcarrier transmission that each subcarrier pair comprises are through the identical constellation symbol of weighting, thereby offset the out-of-band radiation signal that two OFDM subcarriers that each subcarrier pair comprises produce, so reduce the out-of-band radiation of the OFDM baseband signal generation that forms, so reduce the out-of-band radiation of the OFDM baseband signal generation that forms, and when the OFDM baseband signal that reduce to form only need to by two default complex weighting coefficients with constellation symbol mapped in subcarrier pair corresponding to this constellation symbol, decrease computation complexity.

Embodiment 6

As shown in figure 10, the embodiment of the present invention provides a kind of receiving system that reduces out-of-band radiation, and this device recovers constellation symbol from the OFDM baseband signal that embodiment 5 forms, comprising:

Obtain module 601, be used for receiving the OFDM baseband signal, remove the Cyclic Prefix in this OFDM baseband signal, and this OFDM baseband signal is carried out fast Fourier transform obtain each subcarrier pair that the OFDM baseband signal comprises;

Extraction module 602 is used for extracting from two OFDM subcarriers that each subcarrier pair comprises two emission symbols that each subcarrier pair transmits;

Merge module 603, be used for merging every height and carry two emission symbols to transmission and obtain every height and carry a constellation symbol to correspondence.

Wherein, merge module 603, concrete two emission symbol normalization additions that are used for each subcarrier pair transmission obtain a constellation symbol corresponding to each subcarrier pair.

Wherein, merge module 603, concrete two emission symbols for by following formula (1), each subcarrier pair being transmitted carry out the normalization addition and obtain a constellation symbol corresponding to each subcarrier pair,

$\hat{s}=\frac{1}{\sqrt{2}}({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA0000104056490000032.png"\; state="\{\{state\}\}">s</figure-callout>}}_1+s_2)......\left(1\right);$

Wherein, in formula (1) Be constellation symbol corresponding to subcarrier pair, s ₁And s ₂Two emission symbols for this subcarrier pair transmission.

In embodiments of the present invention, receive the OFDM baseband signal, obtain each subcarrier pair that this OFDM baseband signal comprises, carry extracting two emission symbols of each subcarrier pair transmission two OFDM subcarriers that comprise from every height, two emission symbols of each subcarrier pair transmission of normalization addition obtain a constellation symbol corresponding to each subcarrier pair, the constellation symbol that the data bit flow that recovers the transmitting terminal transmission from the OFDM baseband signal like this comprises.

One of ordinary skill in the art will appreciate that all or part of step that realizes above-described embodiment can complete by hardware, also can come the relevant hardware of instruction to complete by program, described program can be stored in a kind of computer-readable recording medium, the above-mentioned storage medium of mentioning can be read-only memory, disk or CD etc.

The above is only preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, is equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (16)

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

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

Form the OFDM baseband signal to carrying out inverse FFT through the data bit flow described to be sent after mapping and inserting Cyclic Prefix, launch described OFDM baseband signal.

2. the method for claim 1, it is characterized in that, on two OFDM subcarriers that described each constellation symbol mapped that data bit flow to be sent is comprised by two default complex weighting coefficients comprises to subcarrier pair corresponding to described each constellation symbol, comprising:

By two default complex weighting coefficients, each constellation symbol that described data bit flow to be sent comprises is weighted, obtains emission symbol corresponding to described each constellation symbol pair, described emission symbol is to comprising two emission symbols;

Be that described each constellation symbol selects corresponding subcarrier pair, on two OFDM subcarriers that the emission symbol that described each constellation symbol is corresponding comprises to subcarrier pair corresponding to described each constellation symbol two emission sign map comprising.

3. method as claimed in claim 2, is characterized in that, describedly by two default complex weighting coefficients, each constellation symbol that described data bit flow to be sent comprises is weighted, and obtains emission symbol corresponding to described each constellation symbol pair, comprising:

Described each constellation symbol is obtained two emission symbols corresponding to described each constellation symbol with described default two complex weighting multiplication respectively, and two emission symbols that described each constellation symbol is corresponding form emission symbol corresponding to described each constellation symbol pair.

4. method as claimed in claim 2, is characterized in that, described is after described each constellation symbol is selected corresponding subcarrier pair, also to comprise:

If there is unselected subcarrier pair, the default numerical value of mapping in the subcarrier that comprises to described unselected subcarrier pair.

5. method as described in claim 1-4, is characterized in that, described two complex weighting coefficients are respectively+and 1 and-1.

6. a method of reseptance that reduces out-of-band radiation, is characterized in that, described method comprises:

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

Extract two emission symbols of described each subcarrier pair transmission from two OFDM subcarriers that described each subcarrier pair comprises;

Merging described every height carries two emission symbols to transmission and obtains described every height and carry a constellation symbol to correspondence.

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

Two emission symbols to described each subcarrier pair transmission carry out the normalization addition, obtain a constellation symbol corresponding to described each subcarrier pair.

8. method as described in claim 6 or 7, is characterized in that, the described every height of described merging carries two emission symbols to transmission and obtains described every height and carry a constellation symbol to correspondence, comprising:

By following formula (1), two emission symbols of described each subcarrier pair transmission are carried out the normalization addition and obtain a constellation symbol corresponding to described each subcarrier pair,

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

Wherein, in formula (1)

Be constellation symbol corresponding to subcarrier pair, s ₁And s ₂Two emission symbols for described subcarrier pair transmission.

9. an emitter that reduces out-of-band radiation, is characterized in that, described device comprises:

Divide module, be used for the 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, two OFDM subcarriers that each constellation symbol mapped that is used for by two complex weighting coefficients, data bit flow to be sent being comprised comprises to described subcarrier pair corresponding to described each constellation symbol, the out-of-band radiation that produces to offset described two OFDM subcarriers;

Modulation module is used for forming the OFDM baseband signal to carrying out inverse FFT through the data bit flow described to be sent after mapping and inserting Cyclic Prefix, launches described OFDM baseband signal.

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

Weighted units is used for by two default complex weighting coefficients, each constellation symbol that described data bit flow to be sent comprises being weighted, and obtains emission symbol corresponding to described each constellation symbol pair, and described emission symbol is to comprising two emission symbols;

The first map unit, be used to described each constellation symbol to select corresponding subcarrier pair, in two OFDM subcarriers that the emission symbol that described each constellation symbol is corresponding comprises to subcarrier pair corresponding to described each constellation symbol two emission sign map comprising.

11. device as claimed in claim 10 is characterized in that,

Described weighted units, concrete being used for obtains two emission symbols corresponding to described each constellation symbol with described two default complex weighting multiplication respectively with described each constellation symbol, emission symbol corresponding to two described each constellation symbol of emission symbols composition that described each constellation symbol is corresponding pair.

12. device as claimed in claim 10 is characterized in that, described mapping block also comprises:

The second map unit, if be used for existing unselected subcarrier pair, the default numerical value of mapping in the subcarrier that comprises to described unselected subcarrier pair.

13. device as described in claim 9-12 is characterized in that, described two complex weighting coefficients are respectively+and 1 and-1.

14. a receiving system that reduces out-of-band radiation is characterized in that, described device comprises:

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

Extraction module is used for extracting from two OFDM subcarriers that described each subcarrier pair comprises two emission symbols that described each subcarrier pair transmits;

Merge module, be used for merging described every height and carry two emission symbols to transmission and obtain described every height and carry a constellation symbol to correspondence.

15. device as claimed in claim 14 is characterized in that,

Described merging module, concrete being used for carried out the normalization addition to two emission symbols of described each subcarrier pair transmission, obtains a constellation symbol corresponding to described each subcarrier pair.

16. device as described in claims 14 or 15 is characterized in that,

Described merging module, concrete two emission symbols for by following formula (1), described each subcarrier pair being transmitted carry out the normalization addition and obtain a constellation symbol corresponding to described each subcarrier pair,

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

Wherein, in formula (1)

Be constellation symbol corresponding to subcarrier pair, s ₁And s ₂Two emission symbols for described subcarrier pair transmission.

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