CN105406913A - Signal processing method, device and China mobile multimedia broadcasting system - Google Patents

Abstract

The embodiment of the invention provides a signal processing method, a device and a China mobile multimedia broadcasting system. By adopting the method, the device and the system provided by the embodiment of the invention, a broadcasting signal and a distribution signal which are two received independent signals are compensated, a maximum ratio combining technique is adopted for combination and output, the defect that diversity gain is relatively low when a selective combining technique is adopted in the case of diversity combining in the prior art to select a strong path of signals to be outputted can be overcome, and the purpose of improving the channel gain is realized.

Description

Signal processing method, device and China Mobile multimedia broadcasting system

Technical field

The present invention relates to communication technical field, relate to a kind of signal processing method, device and China Mobile multimedia broadcasting system more specifically.

Background technology

In mobile communication system, mobile telecommunication channel is a kind of multidiameter fading channel, its signal launched will through direct projection, many the propagation paths such as reflection and scattering could arrive receiving terminal, and along with China Mobile multimedia broadcasting system (CMMB, ChinaMobileMultimediaBroadcasting) movement of mobile terminal in, signal burden on each bar propagation path, time delay and phase place change whenever and wherever possible, therefore, the level fluctuation of the signal that receiver receives is unstable, the mutual superposition of multipath signal of these outs of phase then forms multipath fading.

Inventor finds in the process realizing the invention, usual employing diversity reception overcomes multipath fading, adopt and receive carrying identical information and the separate multiple signals of fading characteristic by multiple channel in this way, when multiple signal merges by receiving terminal, alternative amalgamate technology is adopted therefrom to select, compared with the signal of Qiang mono-road signal as final acceptance, to cause system gain relatively low.

Summary of the invention

In view of this, the invention provides a kind of signal processing method, device and China Mobile multimedia broadcasting system, during in order to solve that in prior art, multiple signal merges by receiving terminal, alternative amalgamate technology is adopted therefrom to select compared with Qiang mono-road signal as the final signal accepted, cause the problem that system gain is relatively low, its technical scheme is as follows:

A kind of signal processing method, is applied to China Mobile multimedia broadcasting system, comprises:

Receive the broadcast singal and distribute signals that adopt frequency diversity technique to send respectively, described broadcast singal receives via broadcast channel, and described distribute signals receives via distribution channels;

Respectively synchronous and multicarrier demodulation are carried out to described broadcast singal and described distribute signals, obtain the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals;

The broadcast channel frequency domain impulse response of described broadcast channel is gone out according to the calculated signals on described first subcarrier;

The distribution channels frequency domain impulse response of described distribution channels is gone out according to the calculated signals on described second subcarrier;

According to described broadcast channel frequency domain impulse response, the signal on described first subcarrier is carried out to the compensation of signal amplitude and phase place;

According to described distribution channels frequency domain impulse response, the signal on described second subcarrier is carried out to the compensation of signal amplitude and phase place;

By the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle;

Described 3rd signal is carried out channel-decoding.

Wherein, the described broadcast channel frequency domain impulse response going out described broadcast channel according to the calculated signals on described first subcarrier specifically comprises:

The first scattered pilot subcarrier is extracted from the signal described first subcarrier;

According to the scattered pilot data of the signal on described first discrete subcarrier and described first discrete subcarrier, calculated the broadcast channel estimated value of described broadcast channel by least mean-square error;

Using described broadcast channel estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described broadcast channel frequency domain impulse response.

Wherein, the described distribution channels frequency domain impulse response going out described distribution channels according to the calculated signals on described second subcarrier specifically comprises:

The second scattered pilot subcarrier is extracted from the signal described second subcarrier;

According to the scattered pilot data of the signal on described second discrete subcarrier and described second discrete subcarrier, calculated the distribution channels estimated value of described distribution channels by least mean-square error;

Using described distribution channels estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described distribution channels frequency domain impulse response.

Wherein, described by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle and specifically comprise:

Calculate the broadcast channel fading gains h of described broadcast singal respectively ₀with the distribution channels fading gains h of described distribute signals ₁;

Calculate described broadcast channel fading gains h respectively ₀with described distribution channels fading gains h ₁conjugation h ₀ ^*and h ₁ ^*;

Foundation obtain described 3rd signal, wherein, represent described 3rd signal, represent the conjugation of broadcast channel fading gains, r ₀represent the signal on described first subcarrier after compensating, h ₁ ^*represent the conjugation of distribution channels fading gains, r ₁represent the signal on described second subcarrier after compensating.

A kind of signal processing apparatus, is applied to China Mobile multimedia broadcasting system, comprises:

First receiver module, for receiving the broadcast singal adopting frequency diversity technique to send, described broadcast singal is that described first receiver module receives via broadcast channel;

Second receiver module, for receiving the distribute signals adopting frequency diversity technique to send, described distribute signals is that described second receiver module receives via distribution channels;

Demodulation module, for carrying out synchronous and multicarrier demodulation to described broadcast singal and described distribute signals respectively, obtains the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals;

First computing module, for going out the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier;

Second computing module, for going out the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier;

First compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described first subcarrier according to described broadcast channel frequency domain impulse response;

Second compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described second subcarrier according to described distribution channels frequency domain impulse response;

Merge module, for by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle;

Decoder module, for carrying out channel-decoding by described 3rd signal.

Wherein, described first computing module specifically comprises:

First extraction unit, for extracting the first scattered pilot subcarrier from the signal on described first subcarrier;

First computing unit, for the scattered pilot data according to the signal on described first discrete subcarrier and described first discrete subcarrier, calculates the broadcast channel estimated value of described broadcast channel by least mean-square error;

First acquiring unit, for using described broadcast channel estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described broadcast channel frequency domain impulse response.

Wherein, described second computing module specifically comprises:

Second extraction unit, for extracting the second scattered pilot subcarrier from the signal on described second subcarrier;

Second computing unit, for the scattered pilot data according to the signal on described second discrete subcarrier and described second discrete subcarrier, calculates the distribution channels estimated value of described distribution channels by least mean-square error;

Second acquisition unit, for using described distribution channels estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described distribution channels frequency domain impulse response.

Wherein, described merging module specifically comprises:

3rd computing unit, for calculating the broadcast channel fading gains h of described broadcast singal respectively ₀with the distribution channels fading gains h of described distribute signals ₁;

4th computing unit, for calculating described broadcast channel fading gains h respectively ₀with described distribution channels fading gains h ₁conjugation h ₀ ^*and h ₁ ^*;

3rd acquiring unit, for foundation obtain described 3rd signal, wherein, represent described 3rd signal, represent the conjugation of broadcast channel fading gains, r ₀represent the signal on described first subcarrier after compensating, represent the conjugation of distribution channels fading gains, r ₁represent the signal on described second subcarrier after compensating.

A kind of China Mobile multimedia broadcasting system, comprising:

First receiver, for receiving the broadcast singal adopting frequency diversity technique to send, described broadcast singal is that described first receiver module receives via broadcast channel;

Second receiver, for receiving the distribute signals adopting frequency diversity technique to send, described distribute signals is that described second receiver module receives via distribution channels;

Demodulator, for carrying out synchronous and multicarrier demodulation to described broadcast singal and described distribute signals respectively, obtains the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals;

Processor, comprises the first computing module, for going out the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier; Second computing module, for going out the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier; First compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described first subcarrier according to described broadcast channel frequency domain impulse response; Second compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described second subcarrier according to described distribution channels frequency domain impulse response; Merge module, for by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle;

Decoder, for carrying out channel-decoding by described 3rd signal.

Technique scheme has following beneficial effect:

Signal processing method disclosed in the embodiment of the present invention, after the broadcast singal received and distribute signals two independent signals are compensated, adopt maximum-ratio combing technology to merge to export, overcoming prior art adopts alternative amalgamate technology therefrom to select to export the relatively low shortcoming of time diversity gain compared with Qiang mono-road signal when diversity merges, achieve the object improving channel gain.

Accompanying drawing explanation

The schematic flow sheet of a kind of implementation of a kind of signal processing method that Fig. 1 provides for the embodiment of the present invention;

Go out the schematic flow sheet of a kind of implementation method of the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier in a kind of signal processing method that Fig. 2 provides for the embodiment of the present invention;

Go out the schematic flow sheet of a kind of implementation method of the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier in a kind of signal processing method that Fig. 3 provides for the embodiment of the present invention;

By the signal on described first subcarrier after compensating and the signal on described second subcarrier in a kind of signal processing method that Fig. 4 provides for the embodiment of the present invention, merge into the method flow schematic diagram of a kind of implementation of the 3rd signal according to maximum-ratio combing principle;

The structural representation of a kind of implementation of a kind of signal processing apparatus that Fig. 5 provides for the invention process;

The structural representation of a kind of implementation of module is merged in the signal processing apparatus that Fig. 6 provides for the embodiment of the present invention.

By the signal on described first subcarrier after compensating and the signal on described second subcarrier in Fig. 7 a kind of signal processing method disclosed in the embodiment of the present invention, merge into the schematic diagram of a kind of account form of the 3rd signal according to maximum-ratio combing principle.

Embodiment

For the purpose of quoting and know, the explanation of the technical term hereinafter used, write a Chinese character in simplified form or abridge and be summarized as follows:

CMMB, ChinaMobileMultimediaBroadcasting, China Mobile multimedia broadcasting system;

FFT:FastFourierTransformation, fast Fourier transform;

LDPC:LowDensityParityCheckCode, low density parity check code;

OFDM:OrthogonalFrequencyDivisionMultiplexing, orthogonal frequency division multiplexi;

MMSE: least mean-square error;

ML:MaximumLikelihood, Maximum Likelihood Detection.

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Refer to Fig. 1, the schematic flow sheet of a kind of implementation of a kind of signal processing method provided for the embodiment of the present invention, the method can be applied to China Mobile multimedia broadcasting system, and the method comprises:

Step S101: receive the broadcast singal and distribute signals that adopt frequency diversity technique to send respectively.

Described broadcast singal receives via broadcast channel, and described distribute signals receives via distribution channels.

Step S102: respectively synchronous and multicarrier demodulation are carried out to described broadcast singal and described distribute signals, obtain the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals.

Transmitting terminal can frequency of utilization diversity technique, and broadcast singal can frequency of utilization f ₁send, distribute signals is frequency of utilization f after ground supplement transmission network forwards ₂send.

In CMMB system, modulate the data after Bit Interleave and control information through broadcast channel, formed distribute signals and send to receiving terminal through distribution channels.

In order to solve satellite-signal shadow region quorum sensing inhibitor less than problem, establish ground supplement transmission network.

Receiving terminal can use the signal of two receivers to different frequency to receive, and such as the first receiver receive frequency is f ₁broadcast singal, the second receiver receive frequency is f ₂distribute signals.Analog-to-digital conversion can also be carried out to the distribute signals received and broadcast singal, obtain the serial signal corresponding with distribute signals and the serial signal corresponding with broadcast singal, above-mentioned two-way serial data is converted to baseband signal through down-sampling.

Signal on above-mentioned first subcarrier can be the baseband signal corresponding with broadcast singal, and the signal on the second subcarrier can be the baseband signal corresponding with distribute signals.

Carry out synchronously can comprising to described broadcast singal and described distribute signals: carry out synchronous and fast Fourier transform FFT computing to broadcast singal and distribute signals, obtain the Delay of broadcast singal and distribute signals, according to Delay, delay compensation is carried out to the broadcast singal after computing and distribute signals.

According to the structure of CMMB system, synchronously mainly contain slot synchronization and sign synchronization, wherein slot synchronization be mainly used to detect time slot whether arrive, CMMB system placed two identical synchronizing signals in the beacon of each time slot, can be determined the original position of time slot by the related operation of synchronizing signal and local known array.The original position of sign synchronization mainly estimating OFDM symbol, to determine FFT window original position, sign synchronization utilizes the discrete guide-frequency signal of frequency domain to estimate synchronous error, and corrects this error.Multicarrier demodulation is that the broadcast singal received and distribute signals are removed to Cyclic Prefix and carried out FFT conversion, demodulates the signal on the first subcarrier and the second subcarrier.

Step S103: the broadcast channel frequency domain impulse response going out described broadcast channel according to the calculated signals on described first subcarrier.

Step S104: the distribution channels frequency domain impulse response going out described distribution channels according to the calculated signals on described second subcarrier.

Can be carry out between step S103 and step S104, also can be that step S103 performs prior to step S104 simultaneously, and can be that step S104 performs prior to step S103, the embodiment of the present invention do concrete restriction to this yet.

Step S105: the compensation according to described broadcast channel frequency domain impulse response, the signal on described first subcarrier being carried out to signal amplitude and phase place.

Step S106: the compensation according to described distribution channels frequency domain impulse response, the signal on described second subcarrier being carried out to signal amplitude and phase place.

Concrete, can according to the channel frequency impulse response Η obtained, the change of signal amplitude on the change of signal amplitude on every first subcarrier and phase place and the second subcarrier and phase place is compensated by frequency-domain equalization technology.

Can be carry out between step S105 and step S106, also can be that step S105 performs prior to step S106 simultaneously, and can be that step S106 performs prior to step S105, the embodiment of the present invention do concrete restriction to this yet.

Step S107: by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle.

Step S108: described 3rd signal is carried out channel-decoding.

3rd signal is carried out demapping, deinterleaving, LDPC decoding, RS decoding etc., finally recovers initial data, be i.e. the signal that sends out of transmitting terminal.

The embodiment of the present invention is for China Mobile multimedia broadcasting system, the technology of diversity reception is adopted to make full use of broadcast singal and distribute signals two paths of signals, overcome in prior art and the shortcoming that timing_delay estimation realized synchronously, only went to improve from the angle of signal transacting the signal received is carried out to broadcast channel and distribution channels two paths of signals, ensure to realize higher gain from the angle of energy.

Signal processing method disclosed in the embodiment of the present invention, after the broadcast singal received and distribute signals two independent signals are compensated, adopt maximum-ratio combing technology to merge to export, overcoming prior art adopts alternative amalgamate technology therefrom to select to export the relatively low shortcoming of time diversity gain compared with Qiang mono-road signal when diversity merges, achieve the object improving channel gain.

Refer to Fig. 2, for going out the schematic flow sheet of a kind of implementation method of the broadcast channel frequency domain impulse response of described broadcast channel in a kind of signal processing method that the embodiment of the present invention provides according to the calculated signals on described first subcarrier, the method comprises:

Step S201: extract the first scattered pilot subcarrier from the signal described first subcarrier.

Receiving terminal can carry out synchronous and FFT conversion to the broadcast singal received and distribute signals, demodulates the signal on the first subcarrier, extracts the first scattered pilot subcarrier R from the first sub-carrier signal demodulated _p.

Step S202: according to the scattered pilot data of the signal on described first discrete subcarrier and described first discrete subcarrier, calculated the broadcast channel estimated value of described broadcast channel by least mean-square error.

According to the signal R that the first scattered pilot received over subcarriers arrives _pand the first known scattered pilot data X of discrete subcarrier _p, try to achieve broadcast channel estimated value H by Minimum Mean Squared Error estimation MMSE algorithm _p.

Step S203: using described broadcast channel estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtains described broadcast channel frequency domain impulse response.

Channel filtering interpolation can adopt interpolation filter to perform.

Refer to Fig. 3, for going out the schematic flow sheet of a kind of implementation method of the distribution channels frequency domain impulse response of described distribution channels in a kind of signal processing method that the embodiment of the present invention provides according to the calculated signals on described second subcarrier, the method comprises:

Step S301: extract the second scattered pilot subcarrier from the signal described second subcarrier.

Receiving terminal can carry out synchronous and FFT conversion to the broadcast singal received and distribute signals, demodulates the signal on the second subcarrier, extracts the second scattered pilot subcarrier R from the second sub-carrier signal demodulated _p.

Step S302: according to the scattered pilot data of the signal on described second discrete subcarrier and described second discrete subcarrier, calculated the distribution channels estimated value of described distribution channels by least mean-square error.

According to the signal R that the second scattered pilot received over subcarriers arrives _pand the second known scattered pilot data X of discrete subcarrier _p, try to achieve distribution channels estimated value H by Minimum Mean Squared Error estimation MMSE algorithm _p.

Step S303: using described distribution channels estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtains described distribution channels frequency domain impulse response.

Channel filtering interpolation can adopt interpolation filter to perform.

Refer to Fig. 4, for in a kind of signal processing method that the embodiment of the present invention provides by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the method flow schematic diagram of a kind of implementation of the 3rd signal according to maximum-ratio combing principle, the method comprises:

Step S401: the broadcast channel fading gains h calculating described broadcast singal respectively ₀with the distribution channels fading gains h of described distribute signals ₁.

Suppose that the signal that transmitting terminal sends is s ₀, this receives through broadcast channel and distribution channels receiving end.Suppose that broadcast channel and distribution channels are flat fadings, two channels can be modeled as the product of amplitude and phase response.

$h_0={\mathrm{\α}}_0{e}^{-{\mathrm{j\φ}}_0}$

$h_1={\mathrm{\α}}_1{e}^{-{\mathrm{j\φ}}_1}$

Wherein, h ₀represent the broadcast channel fading gains of broadcast singal, h ₁represent the distribution channels fading gains of distribute signals, α ₀represent the amplitude of broadcast channel, φ ₀represent the phase place of broadcast channel; α ₁represent the amplitude of distribution channels, φ ₁represent the phase place of distribution channels.

Step S402: calculate described broadcast channel fading gains h respectively ₀with described distribution channels fading gains h ₁conjugation h ₀ ^*and h ₁ ^*.

Step S403: foundation obtain described 3rd signal, wherein, represent described 3rd signal, represent the conjugation of broadcast channel fading gains, r ₀represent the signal on described first subcarrier after compensating, represent the conjugation of distribution channels fading gains, r ₁represent the signal on described second subcarrier after compensating.

Namely step S403 is added by adopting corresponding fading gains to be again weighted two paths of signals again, merge into a road signal i.e. the 3rd signal to export, refer to Fig. 7, by the signal on described first subcarrier after compensating and the signal on described second subcarrier in a kind of signal processing method disclosed in the embodiment of the present invention, merge into the schematic diagram of a kind of account form of the 3rd signal according to maximum-ratio combing principle.

Wherein, corresponding fading gains is again specially: broadcast channel fading gains h ₀conjugation h ₀ ^*with distribution channels fading gains h ₁conjugation h ₁ ^*.

Consider the impact of noise and interference, the signal received can be expressed as: r ₀=h ₀s ₀+ n ₀; r ₁=h ₁s ₀+ n ₁, wherein, r ₀represent the broadcast singal of the broadcast channel that the first receiver receives, r ₁represent the distribute signals of the distribution channels that the second receiver receives, h ₀represent the broadcast channel fading gains of broadcast channel, h ₁represent the distribution channels fading gains of distribution channels, s ₀represent actual transmission signal, n ₀represent the multiple Noise and Interference of broadcast channel, n ₁represent the multiple Noise and Interference of distribution channels.

The advantage of maximum-ratio combing and object is selected to be when signal merges, the maximum signal to noise ratio exported after maximum-ratio combing is the cumulative summation of each branch road signal to noise ratio, in theory, when two-way diversity, the average signal-to-noise ratio of maximum-ratio combing is improved as 10log2 ≈ 3dB, can obtain the diversity gain of 3dB.

3rd signal can be carried out Maximum Likelihood Detection, Maximum Likelihood Detection is that the maximal possibility estimation carried out to received signal, is a kind of very ripe algorithm, is no longer described in detail at this according to maximum-likelihood criterion.

Describe method in detail in embodiment disclosed in the invention described above, the device of various ways can be adopted to realize for method of the present invention, therefore the invention also discloses multiple device, provide specific embodiment below and be described in detail.

Refer to Fig. 5, the structural representation of a kind of implementation of a kind of signal processing apparatus provided for the invention process, this signal processing apparatus can be applied to China Mobile multimedia broadcasting system, this signal processing apparatus comprises: the first receiver module 501, second receiver module 502, demodulation module 503, first computing module 504, second computing module 505, first compensating module 506, second compensating module 507, merging module 508, decoder module 509, wherein:

First receiver module 501, for receiving the broadcast singal adopting frequency diversity technique to send.

Described broadcast singal is that described first receiver module receives via broadcast channel.

Second receiver module 502, for receiving the distribute signals adopting frequency diversity technique to send.

Described distribute signals is that described second receiver module receives via distribution channels.

Transmitting terminal can frequency of utilization diversity technique, and broadcast singal can frequency of utilization f ₁send, distribute signals is frequency of utilization f after ground supplement transmission network forwards ₂send.

Receiving terminal can use the signal of two receivers to different frequency to receive, and such as the first receiver module 501 receive frequency is f ₁broadcast singal, the second receiver module 502 receive frequency is f ₂distribute signals.Analog-to-digital conversion can also be carried out to the distribute signals received and broadcast singal, obtain the serial signal corresponding with distribute signals and the serial signal corresponding with broadcast singal, above-mentioned two-way serial data is converted to baseband signal through down-sampling.

Signal on above-mentioned first subcarrier can be the baseband signal corresponding with broadcast singal, and the signal on the second subcarrier can be the baseband signal corresponding with distribute signals.

Carry out synchronously can comprising to described broadcast singal and described distribute signals: carry out synchronous and fast Fourier transform FFT computing to broadcast singal and distribute signals, obtain the Delay of broadcast singal and distribute signals, according to Delay, delay compensation is carried out to the broadcast singal after computing and distribute signals.

According to the structure of CMMB system, synchronously mainly contain slot synchronization and sign synchronization, wherein slot synchronization be mainly used to detect time slot whether arrive, CMMB system placed two identical synchronizing signals in the beacon of each time slot, can be determined the original position of time slot by the related operation of synchronizing signal and local known array.The original position of sign synchronization mainly estimating OFDM symbol, to determine FFT window original position, sign synchronization utilizes the discrete guide-frequency signal of frequency domain to estimate synchronous error, and corrects this error.Multicarrier demodulation is that the broadcast singal received and distribute signals are removed to Cyclic Prefix and carried out FFT conversion, demodulates the signal on the first subcarrier and the second subcarrier.

Demodulation module 503, for carrying out synchronous and multicarrier demodulation to described broadcast singal and described distribute signals respectively, obtains the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals.

First computing module 504, for going out the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier.

Second computing module 505, for going out the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier.

First compensating module 506, for carrying out the compensation of signal amplitude and phase place to the signal on described first subcarrier according to described broadcast channel frequency domain impulse response.

Second compensating module 507, for carrying out the compensation of signal amplitude and phase place to the signal on described second subcarrier according to described distribution channels frequency domain impulse response.

Concrete, can according to the channel frequency impulse response Η obtained, the change of signal amplitude on the change of signal amplitude on every first subcarrier and phase place and the second subcarrier and phase place is compensated by frequency-domain equalization technology.

Merge module 508, for by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle.

Decoder module 509, for carrying out channel-decoding by described 3rd signal.

3rd signal is carried out demapping, deinterleaving, LDPC decoding, RS decoding etc., finally recovers initial data.

The embodiment of the present invention is for China Mobile multimedia broadcasting system, the technology of diversity reception is adopted to make full use of broadcast singal and distribute signals two paths of signals, overcome in prior art and the shortcoming that timing_delay estimation realized synchronously, only went to improve from the angle of signal transacting the signal received is carried out to broadcast channel and distribution channels two paths of signals, ensure to realize higher gain from the angle of energy.

Signal processing apparatus disclosed in the embodiment of the present invention, after the broadcast singal received and distribute signals two independent signals are compensated, adopt maximum-ratio combing technology to merge to export, overcoming prior art adopts alternative amalgamate technology therefrom to select to export the relatively low shortcoming of time diversity gain compared with Qiang mono-road signal when diversity merges, achieve the object improving channel gain.

The first computing module in signal processing apparatus can comprise: the first extraction unit, for extracting the first scattered pilot subcarrier from the signal on described first subcarrier; First computing unit, for the scattered pilot data according to the signal on described first discrete subcarrier and described first discrete subcarrier, calculates the broadcast channel estimated value of described broadcast channel by least mean-square error; First acquiring unit, for using described broadcast channel estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described broadcast channel frequency domain impulse response.

Concrete, receiving terminal can carry out synchronous and FFT conversion to the broadcast singal received and distribute signals, demodulates the signal on the first subcarrier, extracts the first scattered pilot subcarrier R from the first sub-carrier signal demodulated _p.According to the signal R that the first scattered pilot received over subcarriers arrives _pand the first known scattered pilot data X of discrete subcarrier _p, try to achieve broadcast channel estimated value H by Minimum Mean Squared Error estimation MMSE algorithm _p.Channel filtering interpolation can adopt interpolation filter to perform.

In above-mentioned arbitrary signal processing apparatus, the second computing module specifically comprises: the second extraction unit, for extracting the second scattered pilot subcarrier from the signal on described second subcarrier; Second computing unit, for the scattered pilot data according to the signal on described second discrete subcarrier and described second discrete subcarrier, calculates the distribution channels estimated value of described distribution channels by least mean-square error; Second acquisition unit, for using described distribution channels estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described distribution channels frequency domain impulse response.

Concrete, receiving terminal can carry out synchronous and FFT conversion to the broadcast singal received and distribute signals, demodulates the signal on the second subcarrier, extracts the second scattered pilot subcarrier R from the second sub-carrier signal demodulated _p.According to the signal R that the second scattered pilot received over subcarriers arrives _pand the second known scattered pilot data X of discrete subcarrier _p, try to achieve distribution channels estimated value H by Minimum Mean Squared Error estimation MMSE algorithm _p.Channel filtering interpolation can adopt interpolation filter to perform.

Refer to Fig. 6, for merging the structural representation of a kind of implementation of module in the signal processing apparatus that the embodiment of the present invention provides, this signal processing apparatus comprises: the 3rd computing unit 601, the 4th computing unit 602, the 3rd acquiring unit 603, wherein,

3rd computing unit 601, for calculating the broadcast channel fading gains h of described broadcast singal respectively ₀with the distribution channels fading gains h of described distribute signals ₁.

Suppose that the signal that transmitting terminal sends is s ₀, this receives through broadcast channel and distribution channels receiving end.Suppose that broadcast channel and distribution channels are flat fadings, two channels can be modeled as the product of amplitude and phase response.

$h_0={\mathrm{\α}}_0{e}^{-{\mathrm{j\φ}}_0}$

$h_1={\mathrm{\α}}_1{e}^{-{\mathrm{j\φ}}_1}$

Wherein, h ₀represent the broadcast channel fading gains of broadcast singal, h ₁represent the distribution channels fading gains of distribute signals, α ₀represent the amplitude of broadcast channel, φ ₀represent the phase place of broadcast channel; α ₁represent the amplitude of distribution channels, φ ₁represent the phase place of distribution channels.

4th computing unit 602, for calculating described broadcast channel fading gains h respectively ₀with described distribution channels fading gains h ₁conjugation h ₀ ^*and h ₁ ^*.

3rd acquiring unit 603, for foundation obtain described 3rd signal, wherein, represent described 3rd signal, represent the conjugation of broadcast channel fading gains, r ₀represent the signal on described first subcarrier after compensating, represent the conjugation of distribution channels fading gains, r ₁represent the signal on described second subcarrier after compensating.

Consider the impact of noise and interference, the signal received can be expressed as: r ₀=h ₀s ₀+ n ₀; r ₁=h ₁s ₀+ n ₁, wherein, r ₀represent the broadcast singal of the broadcast channel that the first receiver receives, r ₁represent the distribute signals of the distribution channels that the second receiver receives, h ₀represent the broadcast channel fading gains of broadcast channel, h ₁represent the distribution channels fading gains of distribution channels, s ₀represent actual transmission signal, n ₀represent the multiple Noise and Interference of broadcast channel, n ₁represent the multiple Noise and Interference of distribution channels.

The advantage of maximum-ratio combing and object is selected to be when signal merges, the maximum signal to noise ratio exported after maximum-ratio combing is the cumulative summation of each branch road signal to noise ratio, in theory, when two-way diversity, the average signal-to-noise ratio of maximum-ratio combing is improved as 10log2 ≈ 3dB, can obtain the diversity gain of 3dB.

The embodiment of the present invention additionally provides a kind of China Mobile multimedia broadcasting system, and this system comprises:

Transmitting terminal, for adopting frequency diversity technique to send to the first receiver and the second receiver transmission signal; Described first receiver, for receiving the broadcast singal adopting frequency diversity technique to send, described broadcast singal is that described first receiver module receives via broadcast channel; Described second receiver, for receiving the distribute signals adopting frequency diversity technique to send, described distribute signals is that described second receiver module receives via distribution channels; Demodulator, for carrying out synchronous and multicarrier demodulation to described broadcast singal and described distribute signals respectively, obtains the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals; Processor, comprises the first computing module, for going out the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier; Second computing module, for going out the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier; First compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described first subcarrier according to described broadcast channel frequency domain impulse response; Second compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described second subcarrier according to described distribution channels frequency domain impulse response; Merge module, for by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle; Decoder, for described 3rd signal is carried out channel-decoding, obtains the data corresponding with described transmission signal.

In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar portion mutually see.

Also it should be noted that, in this article, the such as relational terms of first and second grades and so on is only used for an entity or operation to separate with another entity or operating space, and not necessarily requires or imply the relation that there is any this reality between these entities or operation or sequentially.And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, thus make to comprise the process of a series of key element, method, article or equipment and not only comprise those key elements, but also comprise other key elements clearly do not listed, or also comprise by the intrinsic key element of this process, method, article or equipment.When not more restrictions, the key element limited by statement " comprising ... ", and be not precluded within process, method, article or the equipment comprising described key element and also there is other identical element.

To the above-mentioned explanation of provided embodiment, professional and technical personnel in the field are realized or uses the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle provided in this article and features of novelty.

Claims (9)

1. a signal processing method, is applied to China Mobile multimedia broadcasting system, it is characterized in that, described signal processing method comprises:

Receive the broadcast singal and distribute signals that adopt frequency diversity technique to send respectively, described broadcast singal receives via broadcast channel, and described distribute signals receives via distribution channels;

Respectively synchronous and multicarrier demodulation are carried out to described broadcast singal and described distribute signals, obtain the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals;

The broadcast channel frequency domain impulse response of described broadcast channel is gone out according to the calculated signals on described first subcarrier;

The distribution channels frequency domain impulse response of described distribution channels is gone out according to the calculated signals on described second subcarrier;

According to described broadcast channel frequency domain impulse response, the signal on described first subcarrier is carried out to the compensation of signal amplitude and phase place;

According to described distribution channels frequency domain impulse response, the signal on described second subcarrier is carried out to the compensation of signal amplitude and phase place;

By the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle;

Described 3rd signal is carried out channel-decoding.

2. signal processing method according to claim 1, is characterized in that, the described broadcast channel frequency domain impulse response going out described broadcast channel according to the calculated signals on described first subcarrier specifically comprises:

The first scattered pilot subcarrier is extracted from the signal described first subcarrier;

According to the scattered pilot data of the signal on described first discrete subcarrier and described first discrete subcarrier, calculated the broadcast channel estimated value of described broadcast channel by least mean-square error;

Using described broadcast channel estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described broadcast channel frequency domain impulse response.

3. signal processing method according to claim 1, is characterized in that, the described distribution channels frequency domain impulse response going out described distribution channels according to the calculated signals on described second subcarrier specifically comprises:

The second scattered pilot subcarrier is extracted from the signal described second subcarrier;

According to the scattered pilot data of the signal on described second discrete subcarrier and described second discrete subcarrier, calculated the distribution channels estimated value of described distribution channels by least mean-square error;

Using described distribution channels estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described distribution channels frequency domain impulse response.

4. signal processing method according to claim 1, is characterized in that, described by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merges into the 3rd signal specifically comprise according to maximum-ratio combing principle:

Calculate the broadcast channel fading gains h of described broadcast singal respectively ₀with the distribution channels fading gains h of described distribute signals ₁;

Calculate described broadcast channel fading gains h respectively ₀with described distribution channels fading gains h ₁conjugation h ₀ ^*and h ₁ ^*;

Foundation obtain described 3rd signal, wherein, represent described 3rd signal, represent the conjugation of broadcast channel fading gains, r ₀represent the signal on described first subcarrier after compensating, represent the conjugation of distribution channels fading gains, r ₁represent the signal on described second subcarrier after compensating.

5. a signal processing apparatus, is applied to China Mobile multimedia broadcasting system, it is characterized in that, comprising:

First receiver module, for receiving the broadcast singal adopting frequency diversity technique to send, described broadcast singal is that described first receiver module receives via broadcast channel;

Second receiver module, for receiving the distribute signals adopting frequency diversity technique to send, described distribute signals is that described second receiver module receives via distribution channels;

Demodulation module, for carrying out synchronous and multicarrier demodulation to described broadcast singal and described distribute signals respectively, obtains the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals;

First computing module, for going out the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier;

Second computing module, for going out the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier;

First compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described first subcarrier according to described broadcast channel frequency domain impulse response;

Second compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described second subcarrier according to described distribution channels frequency domain impulse response;

Merge module, for by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle;

Decoder module, for carrying out channel-decoding by described 3rd signal.

6. signal processing apparatus according to claim 5, it is characterized in that, described first computing module specifically comprises:

First extraction unit, for extracting the first scattered pilot subcarrier from the signal on described first subcarrier;

First computing unit, for the scattered pilot data according to the signal on described first discrete subcarrier and described first discrete subcarrier, calculates the broadcast channel estimated value of described broadcast channel by least mean-square error;

First acquiring unit, for using described broadcast channel estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described broadcast channel frequency domain impulse response.

7. signal processing apparatus according to claim 5, it is characterized in that, described second computing module specifically comprises:

Second extraction unit, for extracting the second scattered pilot subcarrier from the signal on described second subcarrier;

Second computing unit, for the scattered pilot data according to the signal on described second discrete subcarrier and described second discrete subcarrier, calculates the distribution channels estimated value of described distribution channels by least mean-square error;

Second acquisition unit, for using described distribution channels estimated value as sampled point, under the condition meeting nyquist sampling theorem, by channel filtering interpolation, obtain described distribution channels frequency domain impulse response.

8. signal processing apparatus according to claim 1, it is characterized in that, described merging module specifically comprises:

3rd computing unit, for calculating the broadcast channel fading gains h of described broadcast singal respectively ₀with the distribution channels fading gains h of described distribute signals ₁;

4th computing unit, for calculating described broadcast channel fading gains h respectively ₀with described distribution channels fading gains h ₁conjugation h ₀ ^*and h ₁ ^*;

3rd acquiring unit, for foundation obtain described 3rd signal, wherein, represent described 3rd signal, represent the conjugation of broadcast channel fading gains, r ₀represent the signal on described first subcarrier after compensating, represent the conjugation of distribution channels fading gains, r ₁represent the signal on described second subcarrier after compensating.

9. a China Mobile multimedia broadcasting system, is characterized in that, comprising:

Transmitting terminal, for adopting frequency diversity technique to send to the first receiver and the second receiver transmission signal;

Described first receiver, for receiving the broadcast singal adopting frequency diversity technique to send, described broadcast singal is that described first receiver module receives via broadcast channel;

Described second receiver, for receiving the distribute signals adopting frequency diversity technique to send, described distribute signals is that described second receiver module receives via distribution channels;

Demodulator, for carrying out synchronous and multicarrier demodulation to described broadcast singal and described distribute signals respectively, obtains the signal on the first subcarrier corresponding with described broadcast singal, and the signal on the second subcarrier corresponding with described distribute signals;

Processor, comprises the first computing module, for going out the broadcast channel frequency domain impulse response of described broadcast channel according to the calculated signals on described first subcarrier; Second computing module, for going out the distribution channels frequency domain impulse response of described distribution channels according to the calculated signals on described second subcarrier; First compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described first subcarrier according to described broadcast channel frequency domain impulse response; Second compensating module, for carrying out the compensation of signal amplitude and phase place to the signal on described second subcarrier according to described distribution channels frequency domain impulse response; Merge module, for by the signal on described first subcarrier after compensating and the signal on described second subcarrier, merge into the 3rd signal according to maximum-ratio combing principle;

Decoder, for described 3rd signal is carried out channel-decoding, obtains the data corresponding with described transmission signal.