CN103595678A - A discrete pilot signal generation method for digital audio broadcasting signals and an apparatus - Google Patents

Abstract

The invention brings forward a discrete pilot signal generation method for digital audio broadcasting signals and an apparatus. The method comprises the following steps: A, according to a system frame structure, and bit stream pairs are subjected to QPSK constellation mapping to obtain pilot frequency symbols, and the pilot frequency symbols are filled into the positions of discrete pilot frequency elements of effective subcarriers according to a predetermined mode; B, the result obtained through the processing of the step A is subjected to an IFFT to obtain time domain OFDM symbols; C, multiple connection is carried out on the time domain OFDM symbols and a beacon, and physical frame signals comprising the discrete pilot signals are obtained through logic frame framing, subframe distribution, and physical layer signal frame generation. The apparatus comprises a filling module, a conversion module and a framing module. Through the adoption of the method and the apparatus, the non linear distortion can be reduced and the signal quality can be improved without increasing the peak-to-average power ratio of emission signals.

Description

The discrete guide-frequency signal of digital audio broadcasting signal generates method and apparatus

Technical field

The present invention relates to signal process field, particularly a kind of discrete guide-frequency signal of digital audio broadcasting signal generates method and apparatus.

Background technology

In wireless communication field, Multicarrier Transmission Technology has become one of main flow scheme.When application Multicarrier Transmission Technology, need to face the problems such as height power ratio and carrier wave frequency deviation sensitivity.If employing coherent demodulation, receiver also needs to know the real-time response of fading channel.Time changes and disperse is the peculiar character of wireless channel, is also the main contents of radio communication research.

Scattered pilot not only can be realized coherent demodulation by auxiliary receiver, improves the efficiency of transmission of communication system, can also be used to carry out carrier wave frequency deviation tracking, reduces inter-carrier interference.Therefore, when Communication System Design, conventionally take at the middle insertion scattered pilot that transmits at present, and utilize the correlation interpolation of channel to go out the channel response in whole transmission bandwidth.Because scattered pilot takies system bandwidth, but do not carry any information, when design, not only need to consider that channel time changes and the scope of disperse, also need to weigh the relation between the availability of frequency spectrum and channel estimation errors.

The discrete guide-frequency signal of current digital audio broadcasting signal generates the ubiquitous problem of method and apparatus:

Increase the peak-to-average power ratio transmitting, to having relatively high expectations of the devices such as power amplifier, digital to analog converter, cause nonlinear distortion, thereby cause the signal quality of system poor.

Summary of the invention

The invention provides a kind of discrete guide-frequency signal generation method and device, technical scheme is as follows:

A kind of discrete guide-frequency signal generation method of digital audio broadcasting signal, comprise the following steps: A, according to system frame structure, by bit stream pair, pass through the frequency pilot sign that QPSK constellation mapping obtains, according to predetermined way, be filled into the scattered pilot element position of effective subcarrier; B, by the result of processing of step A, by IFFT, obtain time domain OFDM symbol; C, described time domain OFDM symbol and beacon are carried out to multiple connection, through logical frame framing, sub-frame allocation, physical layer signal frame, generate, obtain the physical frame signal that comprises discrete guide-frequency signal.

Preferably, described system frame structure, comprises physical layer signal frame, subframe, beacon and OFDM symbol; When transmission mode 1, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 56 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers; When transmission mode 2, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 11 1 OFDM symbols, and each OFDM symbol comprises 122 effective subcarriers; When transmission mode 3, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 61 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers.

Preferably, described bit stream pair, the two-way binary pseudo-random sequence being generated by LFSR (Linear Feedback Shift Register, linear feedback shift register) forms; Wherein, described two-way binary pseudo-random sequence adopts pI={pI ₁, pI ₂..., pI _i..., pI _pland pQ={pQ ₁, pQ ₂..., pQ _i..., pQ _plrepresent, described bit stream is to being pI ₁pQ ₁, pI ₂pQ ₂..., pIp _lpQ _pl.

Preferably, when transmission mode 1 or transmission mode 3, the right length of described bit stream is 62*N _i; When transmission mode 2, the right length of described bit stream is 32*N _i; Described N _ifor sub band number, wherein, 1≤N _i≤ 8.

Preferably, the described scattered pilot element position that is filled into effective subcarrier according to predetermined way comprises: steps A 1, determine scattered pilot element position: structure line number is 4*S _n, columns is N _v* N _ieffective subcarrier matrix M, described S _nfor the OFDM symbolic number in each subframe, described N _vfor effective sub-carrier number, described N _ifor sub band number; The line number of described effective subcarrier matrix and columns are all since 1 counting; By described effective subcarrier matrix, by from top to bottom, being from left to right divided into line number, be S _n, columns is N _vsubmatrix M _{s, t}, that is:

$M=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA00001988288200032.png,HDA00001988288200033.png"\; state="\{\{state\}\}">M</figure-callout>}}_{\mathrm{1,1}}& {\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA00001988288200032.png,HDA00001988288200033.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{1,2}}& ...& {\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA00001988288200032.png,HDA00001988288200033.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{1,\mathrm{<figure-callout\; id="2"\; label="N\; I\; M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">N</figure-callout>}}_I}& \\ M_{}{}_{\mathrm{2,1}}& {\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{2,2}}& ...& {\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{2,\mathrm{<figure-callout\; id="3"\; label="N\; I\; M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">N</figure-callout>}}_I}& \\ M_{}{}_{\mathrm{3,1}}& {\mathrm{<figure-callout\; id="3"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{3,2}}& ...& {\mathrm{<figure-callout\; id="3"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{3,\mathrm{<figure-callout\; id="4"\; label="N\; I\; M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">N</figure-callout>}}_I}& \\ M_{}{}_{\mathrm{4,1}}& {\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{4,2}}& ...& {\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{4,N}_I}\end{array}\right],$ Wherein,

m _a,b(a=1,2 ... S _n, b=1,2 ..., N _v) be submatrix M _s,tin element, described element is system information elements or scattered pilot element or data element; The position of scattered pilot element is at submatrix

every a line in b row;

When adopting transmission mode 1 or transmission mode 3, by formula (1), ask the value of b, wherein, 1≤a≤S _n;

$\left.\begin{array}{c}\mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==0\\ b=\left\{\begin{array}{cc}12p+122& p=\mathrm{0,1},...,10\\ 12p+121& p=-10,-9,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==1\\ b=\left\{\begin{array}{cc}12p+126& p=\mathrm{0,1},...,9\\ 12p+117& p=-9,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==2\\ b=\left\{\begin{array}{cc}12p+130& p=\mathrm{0,1},...,9\\ 12p+113& p=-9,-8,...,-\mathrm{1,0}\end{array}\right.\end{array}\right\}---\left(1\right)$

When adopting transmission mode 2, by formula (2), ask the value of b, wherein, 1≤a≤S _n;

$\left.\begin{array}{c}\mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==0\\ b=\left\{\begin{array}{cc}12p+62& p=\mathrm{0,1},...,5\\ 12p+61& p=-5,-4,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==1\\ b=\left\{\begin{array}{cc}12p+66& p=\mathrm{0,1,2,3,4}\\ 12p+57& p=-4,-3,-2,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==2\\ b=\left\{\begin{array}{cc}12p+70& p=\mathrm{0,1,2,3,4}\\ 12p+53& p=-4,-3-,-2,-\mathrm{1,0}\end{array}\right.\end{array}\right\}---\left(2\right)$

Steps A 2, in described scattered pilot element position, fill the described frequency pilot sign obtaining through QPSK constellation mapping:

It is S that matrix M is equally divided into line number from top to bottom _n, columns is N _v* N _isubmatrix M _u, $M_u={\left(m_{c,l}\right)}_{s_N\&times;(N_v\&times;N_I)}(u=\mathrm{1,2,3,4}),$ $M=\left[\begin{array}{c}{M}_1\\ M_2\\ M_3\\ {\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_4\end{array}\right],$ The described frequency pilot sign obtaining through QPSK constellation mapping is filled in to submatrix M from left to right, from top to bottom successively _uthe scattered pilot element position of 1st～3 row on;

M _uthe 4th walk to S _nthe filling mode of the scattered pilot element position of row is as follows, wherein 4≤c≤S _n:

If mod (c-1,3)==0, fills the symbol on the scattered pilot element position of the 1st row on the scattered pilot element position of this journey;

If mod (c-1,3)==1, fills the symbol on the scattered pilot element position of the 2nd row on the scattered pilot element position of this journey;

If mod (c-1,3)==2, fills the symbol on the scattered pilot element position of the 3rd row on the position of the scattered pilot of this journey.

A kind of discrete guide-frequency signal generating apparatus of digital audio broadcasting signal, comprise: packing module, for according to system frame structure, by bit stream pair, pass through the frequency pilot sign that QPSK constellation mapping obtains, according to predetermined way, be filled into the scattered pilot element position of effective subcarrier; Conversion module, for by the result after filling, obtains time domain OFDM symbol by IFFT; Become frame module, for described time domain OFDM symbol and beacon are carried out to multiple connection, through logical frame framing, sub-frame allocation, physical layer signal frame, generate, obtain the physical frame signal that comprises discrete guide-frequency signal.

Preferably, described system frame structure, comprises physical layer signal frame, subframe, beacon and OFDM symbol; When transmission mode 1, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 56 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers; When transmission mode 2, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 111 OFDM symbols, and each OFDM symbol comprises 122 effective subcarriers; When transmission mode 3, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 61 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers.

Preferably, described packing module, comprises LFSR; Wherein, described LFSR is for generation of two-way binary pseudo-random sequence; The generator polynomial of described LFSR is: x ¹¹+ x ⁹+ 1, initial value is 01010100101.

Preferably, when transmission mode 1 or transmission mode 3, the right length of described bit stream is 62*N _i; When transmission mode 2, the right length of described bit stream is 32*N _i; Described N _ifor sub band number, wherein, 1≤N _i≤ 8.

Preferably, described packing module also comprises: determine submodule, for determining scattered pilot element position; Fill submodule, in described scattered pilot element position, fill the described frequency pilot sign obtaining through QPSK constellation mapping.

The discrete guide-frequency signal of digital audio broadcasting signal provided by the invention generates method and apparatus, the beneficial effect producing is as follows: can not increase the peak-to-average power ratio transmitting, make the requirement of the devices such as power amplifier, digital to analog converter lower, reduce nonlinear distortion, improved the signal quality of system.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing of required use during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawing illustrated embodiments other embodiment and accompanying drawing thereof.

Fig. 1 is the digital audio broadcasting signal physical layer frame structure figure of the embodiment of the present invention.

Fig. 2 is the digital audio broadcasting signal spectrum mode figure of the embodiment of the present invention.

Fig. 3 is the discrete guide-frequency signal generation method of the digital audio broadcasting signal of the embodiment of the present invention.

Fig. 4 is the structural representation of the LFSR of the embodiment of the present invention.

Fig. 5 be the embodiment of the present invention by bit stream pair, carry out the planisphere of QPSK mapping.

Fig. 6 be the embodiment of the present invention according to predetermined way, be filled into the flow chart of the scattered pilot element position of effective subcarrier.

Fig. 7 is the discrete guide-frequency signal of the embodiment of the present invention distribution schematic diagram on the effective subcarrier of OFDM.

Fig. 8 is the discrete guide-frequency signal generating apparatus of the digital audio broadcasting signal of the embodiment of the present invention.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.Obviously, described embodiment is only a part of embodiment of the present invention, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills resulting all embodiment under the prerequisite of not paying creative work belong to protection scope of the present invention.

Discrete guide-frequency signal is an indispensable part in the physical layer frame structure of digital audio broadcasting signal, and as shown in Figure 1, each physical layer signal frame of digital audio broadcasting signal comprises the subframe that 4 length are 160ms, and each subframe comprises 1 beacon and S _nindividual OFDM (Orthogonal Frequency Division Multiplexing, orthogonal frequency division multiplexi) symbol.The data of a logical frame of each physical layer signal frame carrying.Digital audio broadcasting signal can consist of a plurality of subbands, and the nominal bandwidth of each subband is 100kHz, and the quantity of subband mostly is 8 most.

As shown in Figure 2, white blocks represents the frequency spectrum not taking; The every pair of twill piece and grey block form a subband, and wherein, twill piece is second subband, and grey block is first subband; The reserved frequency band of reticulate pattern piece representative simulation broadcast singal.Digital audio broadcasting signal has defined two class spectrum modes, i.e. category-A spectrum mode and category-B spectrum mode.Category-A spectrum mode comprises 8 subbands, i.e. A1-A8, and the nominal frequency of each subband is ± (i * 100+50) kHz, i=0,1,2,3; Category-B spectrum mode comprises 7 subbands, i.e. B1-B7, the integral multiple that the nominal frequency of each subband is 100kHz, ± i*100kHz, i=0,1,2,3.Different spectrum modes provides different bandwidth combination and the compatibility to existing analog broadcast signal.N in figure _irepresent the number of subband; Digital audio broadcasting signal has three kinds of transmission modes conventionally, and wherein, transmission mode 1 is pure digi-tal pattern, and transmission mode 2 is for stereo fm is with broadcasting pattern, and transmission mode 3 is for mono FM is with broadcasting pattern.

Table 1 has provided under three kinds of spectrum modes, the effective sub-carrier indices of frequency spectrum that synchronizing signal OFDM symbol is shared.

The sub-carrier indices of table 1 synchronizing signal

Table 2 has provided the system parameters under three kinds of transmission modes.In an effective subband, when the subcarrier of first subband and second subband is all not empty subcarrier entirely, each OFDM symbol comprises N _vthe individual effective subcarrier being formed by continuous pilot, scattered pilot and data subcarrier; In an effective subband, when the subcarrier of first subband or second subband is empty subcarrier entirely, each OFDM symbol comprises N _v/ 2 effective subcarriers that formed by continuous pilot, scattered pilot and data subcarrier.

Table 2 system parameters

Parameter	Symbol	Transmission mode	1	Transmission mode 2	Transmission mode 3
						Subframe lengths (ms)	T sf	160	160	160
OFDM symbol period (ms)	T s	2.804	1.426	2.5786
					OFDM symbol subcarrier spacing (Hz)	Δf	398.4375	796.8750	398.4375
The OFDM symbolic number of each subframe	S N	56	111	61
					Effective sub-carrier number	N v	242	122	242

As shown in Figure 3, the embodiment of the present invention provides a kind of discrete guide-frequency signal generation method of digital audio broadcasting signal, comprises the following steps:

A, according to system frame structure, by bit stream pair, the frequency pilot sign obtaining through QPSK constellation mapping, is filled into the scattered pilot element position of effective subcarrier according to predetermined way; B, by the result of processing of step A, by IFFT, obtain time domain OFDM symbol; C, described time domain OFDM symbol and beacon are carried out to multiple connection, through logical frame framing, sub-frame allocation, physical layer signal frame, generate, obtain the physical frame signal that comprises discrete guide-frequency signal.

Particularly, business datum process scrambler, LDPC (Low Density Parity Check from upper strata, low-density checksum) coding, constellation mapping and sub-carrier interleaving, business description information adopts 1/4 convolution code, Bit Interleave and constellation mapping with system information after scrambler, carries out OFDM modulation with bit stream together with the frequency pilot sign multiple connection obtaining through QPSK constellation mapping.Wherein, OFDM modulated process, be by bit stream pair, the frequency pilot sign obtaining through QPSK constellation mapping is mapped on effective subcarrier of frequency-region signal discretely according to predetermined way, and the frequency-region signal after mapping is carried out to the process that inverse Fourier transform obtains time-domain signal.To after the time domain OFDM symbol obtaining and beacon multiple connection, form logical frame, logical frame forms physical layer signal frame after sub-frame allocation, thereby obtains the physical frame signal that comprises discrete guide-frequency signal.Therefore, the result of processing of step A refers to bit stream pair, and the frequency pilot sign obtaining through QPSK constellation mapping, is mapped on effective subcarrier of frequency-region signal resulting frequency-region signal discretely according to predetermined way.

As shown in Figure 4, described bit stream pair, the two-way binary pseudo-random sequence being generated by LFSR forms; Wherein, described two-way binary pseudo-random sequence adopts pI={pI ₁, pI ₂..., pI _i..., pI _pland pQ={pQ ₁, pQ ₂..., pQ _i..., pQ _plrepresent, described bit stream is to being pI ₁pQ ₁, pI ₂pQ ₂..., pI _plpQ _pl.In the present embodiment, the generator polynomial of LFSR is x ¹¹+ x ⁹+ 1, initial value is 01010100101, and length is pl, and the value of pl is 62*N when transmission mode 1 and transmission mode 3 _i, when transmission mode 2, be 32*N _i, wherein, N _irepresent the number of subband.

As shown in Figure 5, bit stream is to pI ₁pQ ₁, pI ₂pQ ₂..., pI _plpQ _plin each bit stream pair, through QPSK constellation mapping, be corresponding I value and Q value, in figure

As shown in Figure 6, the described scattered pilot element position that is filled into effective subcarrier according to predetermined way comprises:

Steps A 1, determine the position of scattered pilot element:

Structure line number is 4*S _n, columns is N _v* N _ieffective subcarrier matrix M, described S _nfor the OFDM symbolic number in each subframe, described N _vfor effective sub-carrier number, described N _ifor sub band number; The line number of described effective subcarrier matrix and columns are all since 1 counting; By described effective subcarrier matrix, by from top to bottom, being from left to right divided into line number, be S _n, columns is N _vsubmatrix M _{s, t}, that is: $M=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA00001988288200032.png,HDA00001988288200033.png"\; state="\{\{state\}\}">M</figure-callout>}}_{\mathrm{1,1}}& {\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA00001988288200032.png,HDA00001988288200033.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{1,2}}& ...& {\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA00001988288200032.png,HDA00001988288200033.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{1,N}_I}\\ M_{\mathrm{2,1}}& {\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{2,2}}& ...& {\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{2,N}_I}\\ M_{\mathrm{3,1}}& {\mathrm{<figure-callout\; id="3"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{3,2}}& ...& {\mathrm{<figure-callout\; id="3"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{3,N}_I}\\ M_{\mathrm{4,1}}& {\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>\; </figure-callout>}}_{\mathrm{4,2}}& ...& {\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{4,N}_I}\end{array}\right],$ Wherein, m _a,b(a=1,2 ... S _n, b=1,2 ..., N _v) be submatrix M _{s, t}in element, described element is system information elements or scattered pilot element or data element; The position of scattered pilot element is at submatrix

every a line in b row;

When adopting transmission mode 1 or transmission mode 3, by formula (1), ask the value of b, wherein, 1≤a≤S _n;

$\left.\begin{array}{c}\mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==0\\ b=\left\{\begin{array}{cc}12p+122& p=\mathrm{0,1},...,10\\ 12p+121& p=-10,-9,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==1\\ b=\left\{\begin{array}{cc}12p+126& p=\mathrm{0,1},...,9\\ 12p+117& p=-9,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==2\\ b=\left\{\begin{array}{cc}12p+130& p=\mathrm{0,1},...,9\\ 12p+113& p=-9,-8,...,-\mathrm{1,0}\end{array}\right.\end{array}\right\}---\left(1\right)$

When adopting transmission mode 2, by formula (2), ask the value of b, wherein, 1≤a≤S _n;

$\left.\begin{array}{c}\mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==0\\ b=\left\{\begin{array}{cc}12p+62& p=\mathrm{0,1},...,5\\ 12p+61& p=-5,-4,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==1\\ b=\left\{\begin{array}{cc}12p+66& p=\mathrm{0,1,2,3,4}\\ 12p+57& p=-4,-3,-2,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==2\\ b=\left\{\begin{array}{cc}12p+70& p=\mathrm{0,1,2,3,4}\\ 12p+53& p=-4,-3-,-2,-\mathrm{1,0}\end{array}\right.\end{array}\right\}---\left(2\right)$

Steps A 2, on the position of described scattered pilot element, fill the described frequency pilot sign obtaining through QPSK constellation mapping:

It is S that matrix M is equally divided into line number from top to bottom _n, columns is N _v* N _isubmatrix M _u, $M_u={\left(m_{c,l}\right)}_{s_N\&times;(N_v\&times;N_I)}(u=\mathrm{1,2,3,4}),$ $M=\left[\begin{array}{c}{M}_1\\ M_2\\ M_3\\ {\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="HDA00001988288200021.png"\; state="\{\{state\}\}">M</figure-callout>}}_4\end{array}\right],$ The described frequency pilot sign obtaining through QPSK constellation mapping is filled in to submatrix M from left to right, from top to bottom successively _uthe scattered pilot element position of 1st～3 row on;

M _uthe 4th walk to S _nthe filling mode of the scattered pilot element position of row is as follows, wherein 4≤c≤S _n:

If mod (c-1,3)==0, the symbol on the scattered pilot element position of the scattered pilot element position of this journey filling the 1st row;

If mod (c-1,3)==1, the symbol on the scattered pilot element position of the scattered pilot element position of this journey filling the 2nd row;

If mod (c-1,3)==2, fills the symbol on the scattered pilot element position of the 3rd row on the position of the scattered pilot of this journey.

As shown in Figure 7, discrete guide-frequency signal is upper and alternately appearance of data subcarrier/continuous pilot at effective subcarrier (non-virtual subnet carrier wave), and its interval is by maximum time-varying speed and the maximum delay expansion decision of channel.

As shown in Figure 8, the embodiment of the present invention provides a kind of discrete guide-frequency signal generating apparatus in addition, comprise: packing module 101, be used for according to system frame structure, by bit stream pair, pass through the frequency pilot sign that QPSK constellation mapping obtains, according to predetermined way, be filled into the scattered pilot element position of effective subcarrier; Conversion module 102, for by the result after filling, obtains time domain OFDM symbol by IFFT; Become frame module 103, for described time domain OFDM symbol and beacon are carried out to multiple connection, through logical frame framing, sub-frame allocation, physical layer signal frame, generate, obtain the physical frame signal that comprises discrete guide-frequency signal.Wherein, the result after filling refers to bit stream pair, and the frequency pilot sign obtaining through QPSK constellation mapping is filled into the scattered pilot element position of effective subcarrier according to predetermined way.

In the present embodiment, system frame structure, comprises physical layer signal frame, subframe, beacon and OFDM symbol; When transmission mode 1, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 56 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers; When transmission mode 2, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 111 OFDM symbols, and each OFDM symbol comprises 122 effective subcarriers; When transmission mode 3, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 61 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers.

In the present embodiment, described packing module 101, comprises LFSR 104; Wherein, described LFSR104, for generation of two-way binary pseudo-random sequence; Wherein, the generator polynomial of described LFSR 104 is: x ¹¹+ x ⁹+ 1, initial value is 01010100101.When transmission mode 1 or transmission mode 3, the right length of described bit stream is 62*N _i; When transmission mode 2, the right length of described bit stream is 32*N _i; Described N _ifor sub band number, wherein, 1≤N _i≤ 8.

In the present embodiment, described packing module 101 also comprises: determine submodule 105, for determining scattered pilot element position; Fill submodule 106, in described scattered pilot element position, fill the described frequency pilot sign obtaining through QPSK constellation mapping.

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 hardware that instruction is relevant to complete by program, program can be stored in a kind of computer-readable recording medium, program, when carrying out, comprises step of embodiment of the method one or a combination set of.

In addition, each functional unit in embodiments of the present invention can be integrated in a processing module, can be also that the independent physics of unit exists, and also can be integrated in a module two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, and also can adopt the form of software function module to realize.If described integrated module usings that the form of software function module realizes and during as production marketing independently or use, also can be stored in a computer read/write memory medium.

The above-mentioned storage medium of mentioning can be read-only memory, disk or CD etc.

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

Claims (10)

1. the discrete guide-frequency signal generation method of a digital audio broadcasting signal, is characterized in that, comprises the following steps:

A, according to system frame structure, by bit stream pair, the frequency pilot sign obtaining through QPSK constellation mapping, is filled into the scattered pilot element position of effective subcarrier according to predetermined way;

B, by the result of processing of step A, by IFFT, obtain time domain OFDM symbol;

C, described time domain OFDM symbol and beacon are carried out to multiple connection, through logical frame framing, sub-frame allocation, physical layer signal frame, generate, obtain the physical frame signal that comprises discrete guide-frequency signal.

2. method according to claim 1, is characterized in that:

Described system frame structure, comprises physical layer signal frame, subframe, beacon and OFDM symbol;

When transmission mode 1, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 56 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers;

When transmission mode 2, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 111 OFDM symbols, and each OFDM symbol comprises 122 effective subcarriers;

When transmission mode 3, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 61 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers.

3. method according to claim 1, is characterized in that:

Described bit stream pair, the two-way binary pseudo-random sequence being generated by LFSR forms;

Wherein, described two-way binary pseudo-random sequence adopts pI={pI ₁, pI ₂..., pI _i..., pI _pland pQ={pQ ₁, pQ ₂..., pQ _i..., pQ _plrepresent, described bit stream is to being pI ₁pQ ₁, pI ₂pQ ₂..., pI _plpQ _pl.

4. method according to claim 1, is characterized in that:

When transmission mode 1 or transmission mode 3, the right length of described bit stream is 62*N _i;

When transmission mode 2, the right length of described bit stream is 32*N _i;

Described N _ifor sub band number, wherein, 1≤N _i≤ 8.

5. according to the method described in claim 1-4 any one, it is characterized in that, the described scattered pilot element position that is filled into effective subcarrier according to predetermined way comprises:

Steps A 1, determine scattered pilot element position:

Structure line number is 4*S _n, columns is N _v* N _ieffective subcarrier matrix M, described S _nfor the OFDM symbolic number in each subframe, described N _vfor effective sub-carrier number, described N _ifor sub band number; The line number of described effective subcarrier matrix and columns are all since 1 counting; By described effective subcarrier matrix, by from top to bottom, being from left to right divided into line number, be S _n, columns is N _vsubmatrix M _{s, t}, that is: $M=\left[\begin{array}{cccc}{M}_{\mathrm{1,1}}& M_{\mathrm{1,2}}& ...& M_{{1,N}_I}\\ M_{\mathrm{2,1}}& M_{\mathrm{2,2}}& ...& M_{{2,N}_I}\\ M_{\mathrm{3,1}}& M_{\mathrm{3,2}}& ...& M_{{3,N}_I}\\ M_{\mathrm{4,1}}& M_{\mathrm{4,2}}& ...& M_{{4,N}_I}\end{array}\right],$ Wherein,

m _a,b(a=1,2 ... S _n, b=1,2 ..., N _v) be submatrix M _s,tin element, described element is system information elements or scattered pilot element or data element; The position of scattered pilot element is at submatrix

every a line in b row;

When adopting transmission mode 1 or transmission mode 3, by formula (1), ask the value of b, wherein, 1≤a≤S _n;

$\left.\begin{array}{c}\mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==0\\ b=\left\{\begin{array}{cc}12p+122& p=\mathrm{0,1},...,10\\ 12p+121& p=-10,-9,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==1\\ b=\left\{\begin{array}{cc}12p+126& p=\mathrm{0,1},...,9\\ 12p+117& p=-9,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==2\\ b=\left\{\begin{array}{cc}12p+130& p=\mathrm{0,1},...,9\\ 12p+113& p=-9,-8,...,-\mathrm{1,0}\end{array}\right.\end{array}\right\}---\left(1\right)$

When adopting transmission mode 2, by formula (2), ask the value of b, wherein, 1≤a≤S _n;

$\left.\begin{array}{c}\mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==0\\ b=\left\{\begin{array}{cc}12p+62& p=\mathrm{0,1},...,5\\ 12p+61& p=-5,-4,...,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==1\\ b=\left\{\begin{array}{cc}12p+66& p=\mathrm{0,1,2,3,4}\\ 12p+57& p=-4,-3,-2,-\mathrm{1,0}\end{array}\right.\\ \mathrm{If}\mathrm{mod}(a-\mathrm{1,3})==2\\ b=\left\{\begin{array}{cc}12p+70& p=\mathrm{0,1,2,3,4}\\ 12p+53& p=-4,-3-,-2,-\mathrm{1,0}\end{array}\right.\end{array}\right\}---\left(2\right)$

Steps A 2, in described scattered pilot element position, fill the described frequency pilot sign obtaining through QPSK constellation mapping:

It is S that matrix M is equally divided into line number from top to bottom _n, columns is N _v* N _isubmatrix M _u, $M_u={\left(m_{c,l}\right)}_{s_N\&times;(N_v\&times;N_I)}(u=\mathrm{1,2,3,4}),$ $M=\left[\begin{array}{c}{M}_1\\ M_2\\ M_3\\ M_4\end{array}\right],$ The described frequency pilot sign obtaining through QPSK constellation mapping is filled in to submatrix M from left to right, from top to bottom successively _uthe scattered pilot element position of 1st～3 row on;

M _uthe 4th walk to S _nthe filling mode of the scattered pilot element position of row is as follows, wherein 4≤c≤S _n:

If mod (c-1,3)==0, fills the symbol on the scattered pilot element position of the 1st row on the scattered pilot element position of this journey;

If mod (c-1,3)==1, fills the symbol on the scattered pilot element position of the 2nd row on the scattered pilot element position of this journey;

If mod (c-1,3)==2, fills the symbol on the scattered pilot element position of the 3rd row on the scattered pilot element position of this journey.

6. a discrete guide-frequency signal generating apparatus for digital audio broadcasting signal, is characterized in that, comprising:

Packing module, for according to system frame structure, by bit stream pair, passes through the frequency pilot sign that QPSK constellation mapping obtains, and is filled into the scattered pilot element position of effective subcarrier according to predetermined way;

Conversion module, for by the result after filling, obtains time domain OFDM symbol by IFFT;

Become frame module, for described time domain OFDM symbol and beacon are carried out to multiple connection, through logical frame framing, sub-frame allocation, physical layer signal frame, generate, obtain the physical frame signal that comprises discrete guide-frequency signal.

7. device according to claim 6, is characterized in that:

Described system frame structure, comprises physical layer signal frame, subframe, beacon and OFDM symbol;

When transmission mode 1, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 56 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers;

When transmission mode 2, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 111 OFDM symbols, and each OFDM symbol comprises 122 effective subcarriers;

When transmission mode 3, each physical layer signal frame comprises 4 subframes, and each subframe comprises 1 beacon and 61 OFDM symbols, and each OFDM symbol comprises 242 effective subcarriers.

8. device according to claim 6, is characterized in that:

Described packing module, comprises LFSR;

Wherein, described LFSR, for generation of two-way binary pseudo-random sequence;

The generator polynomial of described LFSR is: x ¹¹+ x ⁹+ 1, initial value is 01010100101.

9. device according to claim 6, is characterized in that:

When transmission mode 1 or transmission mode 3, the right length of described bit stream is 62*N _i;

When transmission mode 2, the right length of described bit stream is 32*N _i;

Described N _ifor sub band number, wherein, 1≤N _i≤ 8.

10. according to the device described in claim 6-9 any one, it is characterized in that, described packing module also comprises:

Determine submodule, for determining scattered pilot element position;

Fill submodule, in described scattered pilot element position, fill the described frequency pilot sign obtaining through QPSK constellation mapping.

Images