CN102035781B - Frequency domain equalization error inhibiting method and device used for single-carrier communication receiver - Google Patents

Abstract

The invention discloses a frequency domain equalization error inhibiting method and device used for a single-carrier communication receiver. The frequency domain equalization error inhibiting method is suitable for the single-carrier communication receiver for carrying out signal restoration in a frequency domain. The single-carrier communication receiver obtains channel state information of eachsubcarrier, subcarrier power values and frequency domain equalization results in the frequency domain through rapid Fourier transform. The frequency domain equalization error inhibiting method comprises the steps of: firstly, carrying out frequency domain equalization error detection on each subcarrier, i.e. recognizing subcarriers according with deep recession characteristics according to the channel state information of each carrier; secondly, carrying out frequency domain equalization error elimination according with the deep recession characteristic according to the channel state information of the subcarriers; and thirdly, obtaining a constellation diagram of a time domain through inverse fast Fourier transform.

Description

The inhibition frequency domain equalization error approach and the device thereof that are used for the single carrier communication receiver

Technical field

The invention relates to the single carrier communication receiver, and particularly relevant for a kind of inhibition frequency domain equalization error approach and system thereof that is used in the single carrier communication receiver.

Background technology

The single carrier communication system is widely used in various wireless telecommunication systems at present, for example, the digital speech broadcast system of main flow generally is to use the single carrier communication system at present, and quadrature stroke rate multitask (OFDM) the modulation system of may arranging in pairs or groups is to improve speech quality, information conveying capacity and spectrum efficiency.

Though, the single carrier mechanics of communication adds that quadrature stroke rate multitask modulation tech has higher information to transmit advantages such as quality, higher information conveying capacity and high spectral efficiency, and the receiver of single carrier communication system generally is that employing time domain equalization (Time domain equalization) reduces and obtain the information that the transmitting terminal of single carrier communication system transmits in fact at present.Adopt the mode of frequency domain channel equalization (Frequency domain channel equalization) to go back the information that original sender transmits if change at the receiver of single carrier communication system, the resource of original Digital Signal Processing in the multiplexing single carrier communication system fully, for example: the resource of fast fourier transform (Fast Fourier Transform abbreviates FFT as) computing.In addition, receiver at the single carrier communication system uses frequency domain channel equalization also can save the necessary sef-adapting filter of time domain equalization (Adaptive filter), and then reduces complexity and the circuit production cost of the receiver of single carrier communication system significantly.

Yet, use frequency domain channel equalization still can produce the balancing error (Equalization error) of frequency domain at the receiver of single carrier communication system, and therefore balancing error and cause the communication system quality to worsen.For example, be in when the receiver of single carrier communication system under the situation of degree of depth decline channel (Deep fading channel), the white noise (White noise) of the background of channel can cause quadrature stroke rate multitask modulation middle part one's share of expenses for a joint undertaking carrier wave to receive serious interference at this moment, even cause the signal that is created on the signal constellation (in digital modulation) figure (Constellation Map) behind the frequency domain equalization incorrect, and then cause whole communication quality and communication performance severe exacerbation.

Summary of the invention

From the above, according to example embodiment of the present invention, the invention provides the inhibition frequency domain equalization error approach and the system thereof that are used in the single carrier communication receiver.Described inhibition frequency domain equalization error approach is applicable at frequency domain carries out the single carrier communication receiver that signal recovers.Suppressing the frequency domain equalization error approach comes identification to meet the subcarrier of degree of depth decline feature (Deep fading characteristic) according to channel condition information (Channel state information), the sub-carrier power value of each subcarrier (Sub-carrier), and according to the channel condition information of this a little carrier wave, the subcarrier that meets degree of depth decline feature that picks out is eliminated the processing of frequency domain equalization error (Frequency domainequalization errors).In addition, eliminate the frequency domain equalization error and also adjust the reduction threshold value of eliminating institute's palpus in the frequency domain equalization error by the computing of the self adaptation adjustment reduction factor.

According to example embodiment of the present invention, the present invention proposes a kind of inhibition frequency domain equalization error approach for the single carrier communication receiver.Described inhibition frequency domain equalization error approach is applicable at frequency domain carries out the single carrier communication receiver that signal recovers, and the single carrier communication receiver receives a plurality of subcarriers.Described single carrier communication receiver obtains channel condition information, sub-carrier power value and the frequency domain equalization result of each subcarrier at frequency domain by fast fourier transform.Described inhibition frequency domain equalization error approach is at first carried out the frequency domain equalization error-detecting to each subcarrier, and namely this channel condition information according to each subcarrier comes identification to meet the subcarrier of degree of depth decline feature.Then, according to the channel condition information of the pick out subcarrier that meets degree of depth decline feature, the frequency domain equalization result of pick out each subcarrier that meets degree of depth decline feature is eliminated the frequency domain equalization error.Described elimination frequency domain equalization error comprises: according to the channel condition information power average value of a plurality of subcarriers, calculate a plurality of reduction threshold values; According to the channel condition information performance number and each reduction threshold value of each subcarrier that meets this degree of depth decline feature, select to reduce in a plurality of reduction factors of threshold value one of them corresponding to each; And the frequency domain equalization result that will meet each subcarrier of degree of depth decline feature at present is multiplied by the selected reduction factor, to obtain to eliminate the result of frequency domain equalization error.

According to example embodiment of the present invention, inhibition frequency domain equalization error approach proposed by the invention also comprises a channel condition information performance number of calculating each subcarrier, calculate a channel condition information power average value of subcarrier, the channel condition information power average value of subcarrier is carried out the reduction of channel condition information power average value, obtaining degree of depth decline threshold value, and whether the channel condition information performance number that checks each subcarrier is less than degree of depth decline threshold value.If above-mentioned channel condition information performance number confirms then that less than the degree of depth threshold value that fails the subcarrier that checks at present meets degree of depth decline feature.Otherwise, if above-mentioned channel condition information performance number confirms then that more than or equal to the degree of depth threshold value that fails the subcarrier that checks does not at present meet degree of depth decline feature.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error approach proposed by the invention, the step of above-mentioned elimination frequency domain equalization error comprises also that at first channel condition information performance number and a plurality of reduction threshold value to each subcarrier that meets degree of depth decline feature compares, and reduces a bit since then in the corresponding a plurality of reduction factors in a plurality of reductions interval that threshold value forms and select one of them.In addition, the frequency domain equalization result who meets each subcarrier of degree of depth decline feature at present is multiplied by the selected reduction factor, to obtain to eliminate the result of frequency domain equalization error.In addition, the result to this elimination frequency domain equalization error carries out the planisphere that anti-fast fourier transform obtains time domain.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error approach proposed by the invention, this reduces threshold value a bit is to calculate according to following equation (1) to obtain:

ATT_THD_k=20 * log ₁₀(CSI_Power_mean)-REG_k equation (1)

Wherein, these a little K that add up to that reduce threshold values, K is the positive integer more than or equal to 1, k reduces index value and the k=1 of threshold value for this reason a bit, 2, ..., K, ATT_THD_k are k reduction threshold value, CSI_Power_mean is the channel condition information power average value of each quadrature stroke rate multitask symbol sub-carriers, and REG_k is k pre-set interval spacing value.

According to example embodiment of the present invention, inhibition frequency domain equalization error approach proposed by the invention also comprises result and the frequency domain equalization result according to the frequency domain equalization error-detecting, and each subcarrier is carried out the computing of the self adaptation adjustment reduction factor to produce a step-length.In addition, eliminating the frequency domain equalization error can use the step-length that produces to adjust the required a plurality of reduction threshold values of described elimination frequency domain equalization error.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error approach proposed by the invention, the above-mentioned step-length in order to these a little reduction threshold values is to calculate according to following equation (2) to obtain:

Equation (2)

, wherein, λ is step-length, div_out_deep_fading_power_mean is frequency domain equalization mean value as a result, and div_out_power_mean is degree of depth decline frequency domain equalization mean value as a result.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error approach proposed by the invention, above-mentioned single carrier communication receiver is for using the receiver of digital ground multimedia broadcast (DTMB) standard.

According to example embodiment of the present invention, the present invention proposes a kind of inhibition frequency domain equalization error system for the single carrier communication receiver.Described inhibition frequency domain equalization error system is applicable at frequency domain and carries out the single carrier communication receiver that signal recovers, and the single carrier communication receiver receives a plurality of subcarriers.Described single carrier communication receiver obtains channel condition information, sub-carrier power value and the frequency domain equalization result of each subcarrier by fast fourier transform.Described inhibition frequency domain equalization error system comprises frequency domain equalization error-detecting module and elimination frequency domain equalization error module at least.Described frequency domain equalization error-detecting module is carried out the frequency domain equalization error-detecting to subcarrier.Described frequency domain equalization error-detecting is that the channel condition information according to each subcarrier comes identification to meet the subcarrier of degree of depth decline feature.In addition, eliminating the frequency domain equalization error module can be according to the channel condition information of the pick out subcarrier that meets degree of depth decline feature, and the frequency domain equalization result of each subcarrier of meeting degree of depth decline feature is eliminated the frequency domain equalization error.Described elimination frequency domain equalization error comprises: eliminate the frequency domain equalization error module according to the channel condition information power average value of a plurality of subcarriers, calculate a plurality of reduction threshold values; Eliminate the frequency domain equalization error module according to this channel condition information performance number and each reduction threshold value of each subcarrier that meets this degree of depth decline feature, select to reduce in a plurality of reduction factors of threshold value one of them corresponding to each; And eliminate the frequency domain equalization result that the frequency domain equalization error module will meet each subcarrier of degree of depth decline feature at present and be multiplied by the selected reduction factor, to obtain to eliminate the result of frequency domain equalization error.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error system proposed by the invention, above-mentioned frequency domain equalization error-detecting module is calculated a channel condition information performance number of each subcarrier in the frequency domain equalization error-detecting, and a channel condition information power average value of calculating subcarrier, and above-mentioned channel condition information power average value is that the sum total of a plurality of channel condition information performance numbers of a plurality of subcarriers is divided by the sum of this a little carrier wave.In addition, frequency domain equalization error-detecting module is also carried out channel condition information power average value reduction to the channel condition information power average value of a plurality of subcarriers, to obtain degree of depth decline threshold value.Moreover frequency domain equalization error-detecting module checks that also whether the channel condition information performance number of each subcarrier is less than degree of depth decline threshold value.If in the frequency domain equalization error-detecting, above-mentioned frequency domain equalization error-detecting module acknowledgement channel state information performance number is less than the degree of depth threshold value that fails, and then frequency domain equalization error-detecting module judges that the subcarrier that checks at present meets degree of depth decline feature.Otherwise if in the frequency domain equalization error-detecting, frequency domain equalization error-detecting module acknowledgement channel state information performance number is more than or equal to the degree of depth threshold value that fails, and then frequency domain equalization error-detecting module judges that the subcarrier that checks does not at present meet this degree of depth decline feature.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error system proposed by the invention, above-mentioned elimination frequency domain equalization error module is calculated a plurality of reduction threshold values according to the channel condition information power average value of a plurality of subcarriers.In addition, above-mentioned elimination frequency domain equalization error module compares channel condition information performance number and a plurality of reduction threshold value of each subcarrier of meeting this degree of depth decline feature, and reduces a bit since then in the corresponding a plurality of reduction factors in a plurality of reductions interval that threshold value forms and select one of them.Then, the frequency domain equalization result that above-mentioned elimination frequency domain equalization error module will meet each subcarrier of degree of depth decline feature at present is multiplied by the selected reduction factor, to obtain to eliminate the result of frequency domain equalization error.In addition, eliminate the frequency domain equalization error module and change by inverse-Fourier, obtained the planisphere of time domain by the result who eliminates the frequency domain equalization error.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error system proposed by the invention, above-mentioned elimination frequency domain equalization error module is to obtain a plurality of reduction threshold values according to following equation (3) calculating:

ATT_THD_k=20 * log ₁₀(CSI_Power_mean)-REG_k equation (3)

Wherein, these a little K that add up to that reduce threshold values, K is the positive integer more than or equal to 1, k reduces index value and the k=1 of threshold value for this reason a bit, 2, ..., K, ATT_THD_k are k reduction threshold value, CSI_Power_mean is the channel condition information power average value of a plurality of subcarriers in each quadrature stroke rate multitask symbol, and REG_k is k pre-set interval spacing value.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error system proposed by the invention, above-mentioned inhibition frequency domain equalization error system more comprises self adaptation adjustment reduction factor computing module.Above-mentioned self adaptation adjustment reduction factor computing module carries out the computing of the self adaptation adjustment reduction factor to produce a step-length according to result and the frequency domain equalization result of frequency domain equalization error-detecting to each subcarrier.In addition, above-mentioned elimination frequency domain equalization error can use above-mentioned step-length to adjust a plurality of reduction threshold values required when eliminating the frequency domain equalization error.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error system proposed by the invention, above-mentioned self adaptation adjustment reduction factor computing module is the step-length that obtains a plurality of reduction threshold values according to following equation (4) calculating:

Equation (4)

, wherein, λ is step-length, div_out_deep_fading_powermean is frequency domain equalization mean value as a result, and div_out_power_mean is degree of depth decline frequency domain equalization mean value as a result.

According to example embodiment of the present invention, in the inhibition frequency domain equalization error system proposed by the invention, above-mentioned single carrier communication receiver is for using the receiver of digital ground multimedia broadcast (DTMB) standard.

Based on above-mentioned, example embodiment of the present invention provides inhibition frequency domain equalization error approach and the system thereof that is used in the single carrier communication receiver.Described inhibition frequency domain equalization error approach and system thereof can come identification to meet the subcarrier of degree of depth decline feature according to the performance number of the channel condition information of each subcarrier.In addition, according to the channel condition information of this a little carrier wave, the frequency domain equalization result of the subcarrier that meets degree of depth decline feature that picks out is eliminated the frequency domain equalization error.In addition, the method for the above-mentioned elimination frequency domain equalization error reduction factor of also using the computing of the self adaptation adjustment reduction factor to produce is adjusted the reduction threshold value.Accordingly, the circuit complexity of single carrier communication receiver can be simplified by described inhibition frequency domain equalization error approach and system thereof, and and then reduces the circuit production cost of single carrier communication receiver.

Example embodiment of the present invention cited below particularly, and conjunction with figs. is described in detail below, so that above-mentioned feature and advantage can be become apparent.

Description of drawings

Fig. 1 is the system block diagrams that first example embodiment according to the present invention illustrates a kind of single carrier communication receiver.

Fig. 2 is the system block diagrams that second example embodiment according to the present invention illustrates a kind of inhibition frequency domain equalization error system for the single carrier communication receiver.

Fig. 3 is the system block diagrams that the 3rd example embodiment according to the present invention illustrates a kind of inhibition frequency domain equalization error system for the single carrier communication receiver.

Fig. 4 is the flow chart that second example embodiment according to the present invention illustrates a kind of inhibition frequency domain equalization error approach for the single carrier communication receiver.

Fig. 5 is that the 3rd example embodiment according to the present invention illustrates the another kind of flow chart that is used for the inhibition frequency domain equalization error approach of single carrier communication receiver.

Fig. 6 is the flow chart that the 3rd example embodiment according to the present invention illustrates a kind of identification frequency domain equalization error approach for the single carrier communication receiver.

Fig. 7 is the flow chart that the 3rd example embodiment according to the present invention illustrates a kind of elimination frequency domain equalization error approach for the single carrier communication receiver.

Fig. 8 is the flow chart that the 4th example embodiment according to the present invention illustrates a kind of elimination frequency domain equalization error approach for the single carrier communication receiver.

Fig. 9 is that the 4th example embodiment according to the present invention illustrates a kind of flow chart that reduces factor method for the self adaptation adjustment of single carrier communication receiver.

Figure 10 is the flow chart that the 4th example embodiment according to the present invention illustrates a kind of self adaptation adjustment reduction threshold value method.

Figure 11 is that the 3rd example embodiment illustrate according to the present invention is through the schematic diagram of self adaptation adjustment reduction threshold value.

Figure 12 is according to the schematic diagram of performance number as a result of frequency domain equalization before the 3rd low-pass filtering that example embodiment illustrates of the present invention.

Figure 13 is according to the schematic diagram of performance number as a result of frequency domain equalization after the 3rd low-pass filtering that example embodiment illustrates of the present invention.

Figure 14 is that the 3rd example embodiment according to the present invention illustrates and eliminates behind the balancing error frequency domain equalization schematic diagram of performance number as a result.

Figure 15 is that the 3rd example embodiment according to the present invention illustrates the systematic function curve chart of eliminating single carrier communication receiver before the balancing error.

Figure 16 is that the 3rd example embodiment according to the present invention illustrates the systematic function curve chart of eliminating single carrier communication receiver behind the balancing error.

Embodiment

Now will be in detail with reference to disclosed example embodiment, described example embodiment is illustrated in the accompanying drawing more, and subsidiary one what carry is that identical reference marker is used for the same or analogous assembly of expression in the whole accompanying drawing.

According to example embodiment of the present invention, the invention provides a kind of inhibition frequency domain equalization error approach and system thereof that is used in the single carrier communication receiver.Described inhibition frequency domain equalization error approach and system thereof are applicable at frequency domain and carry out the single carrier communication receiver that signal recovers.Inhibition frequency domain equalization error approach and system thereof come identification to meet the subcarrier of degree of depth decline feature according to the channel condition information of each subcarrier.Or rather, be to judge according to the power of the channel condition information of subcarrier whether its corresponding subchannel is the depth attenuation.In addition, meet the channel condition information of the subcarrier of degree of depth decline feature a bit according to this, the frequency domain equalization result of the pick out subcarrier that meets degree of depth decline feature is eliminated the frequency domain equalization error.In addition, the method for above-mentioned elimination frequency domain equalization error also uses the computing of the self adaptation adjustment reduction factor to produce the frequency domain equalization error that the reduction factor suppresses each subcarrier.Accordingly, the circuit complexity of single carrier communication receiver can be simplified by described inhibition frequency domain equalization error approach and system thereof, and and then reduces the circuit production cost of single carrier communication receiver.In addition, all following example embodiment only are in order to explanation, are not in order to limit the present invention.

At first please refer to Fig. 1, Fig. 1 is the system block diagrams that first example embodiment according to the present invention illustrates a kind of single carrier communication receiver.Single carrier communication receiver 100 carries out signal at frequency domain and recovers, and comprises quick fast fourier transform processing module 112,114, divider 132, anti-fast fourier transform processing module (Inver-Fast Fourier Transform processing module) 150 and error correction forward (Forward errorcorrection) processing module 160.In single carrier communication receiver 100, fast fourier transform processing module 112 receive channel impulse response information 102, a default training sequence obtains by receiving and described channel impulse response (Channel impulseresponse) 102 is for single carrier communication receiver 100.In addition, fast fourier transform processing module 112 produces a channel condition information 122, the frequency domain typical value of the channel impulse response of a plurality of quadrature stroke rate multitask (OFDM) channel that symbol passes through that described channel condition information 122 receives for single carrier communication receiver 100 according to channel impulse response information 102.In brief, fast fourier transform processing module 112 is converted to channel impulse response information 102 channel condition information 122 of frequency domain by time domain by fast fourier transform.Similar ground, 114 of fast fourier transform processing modules receive one and have received time domain frame ontology information (Received time-domain frame body information) 104, and will receive time domain frame ontology information 104 and be converted to subcarrier ontology information 124.And the described time domain frame ontology information 104 that received is that single carrier communication receiver 100 is by obtaining in a plurality of OFDM symbols that receive, and each OFDM symbol comprises a plurality of subcarriers, for example in digital ground multimedia broadcast (DTMB) standard, each OFDM symbol generally includes 3,780 subcarriers.

Please continue with reference to Fig. 1, the divider 132 of single carrier communication receiver 100 is coupled to fast fourier transform processing module 112 and fast fourier transform processing module 114, and receiving channel state information 122 and subcarrier ontology information 124.In addition, divider 132 also is coupled to anti-fast fourier transform processing module 150, and produces a frequency domain equalization result (Div_out) 142 according to channel condition information 122 and subcarrier ontology information 124.What deserves to be mentioned is that at this channel condition information 122 is all obtained by same subcarrier with subcarrier ontology information 124.Divider 132 with the signal value of channel condition information 122 divided by the signal value of subcarrier ontology information 124 to produce the frequency domain equalization result.Or rather, frequency domain equalization result 142 is calculated and is got by following equation (1):

$\mathrm{Div}\_\mathrm{out}=\frac{\mathrm{Subcarrier}\_\mathrm{body}+{\mathrm{<figure-callout\; id="0"\; label="W"\; filenames="H2009101963602E00091.png,H2009101963602E00121.png"\; state="\{\{state\}\}">W</figure-callout>}}_0}{\mathrm{CSI}+{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="H2009101963602E00091.png,H2009101963602E00121.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}$ Equation (1)

, wherein, Div_out is frequency domain equalization result 142, and Subcarrier_body is subcarrier ontology information 124, and CSI is channel condition information 122, W ₀Be the white noise in the subcarrier ontology information 124 (White noise), and N ₀Be the white noise in the channel condition information 122.

Anti-fast fourier transform processing module 150 is coupled to error correction processing module forward 160, and after anti-fast fourier transform processing module 150 is converted to time domain with frequency domain equalization result 142 from frequency domain by anti-fast fourier transform, send error correction processing module forward 160 to and carry out the error correction processing, and follow-up signal is handled.Follow-up signal is handled and to be comprised according to frequency domain equalization result 142 and produce signal at the planisphere of time domain, and tries to achieve fundamental frequency signal according to the signal on the planisphere.Because being treated to having of this area, the follow-up signal of single carrier communication receiver knows that usually the knowledgeable is familiar with, so be not described in detail at this.

The single carrier communication receiver 100 that first example embodiment according to the present invention illustrates only can be gone back the information that original sender (not illustrating) transmits by frequency domain equalization with the OFDM symbol that receives, but and can't suppress the frequency domain equalization error.Below will introduce the inhibition frequency domain equalization error system for the single carrier communication receiver provided by the present invention with Fig. 2 and Fig. 3.

Fig. 2 is the system block diagrams that second example embodiment according to the present invention illustrates a kind of inhibition frequency domain equalization error system for the single carrier communication receiver.Please refer to Fig. 2, the inhibition frequency domain equalization error system 200 that is used for the single carrier communication receiver comprises divider 132, eliminates frequency domain equalization error module 210, anti-fast fourier transform processing module 150 and error correction processing module forward 160.In this example embodiment, divider 132, anti-fast fourier transform processing module 150 and error correction processing module forward 160 are similar with corresponding device or module in first example embodiment, so do not introduce its content in detail at this.

Please continue with reference to Fig. 2, eliminate frequency domain equalization error module 210 and be coupled between divider 132 and the anti-fast fourier transform processing module 150.In addition, eliminate the frequency domain equalization result 214 that frequency domain equalization error module 210 receiving channel state informations 122, subcarrier ontology information 124 and divider 132 produce.Moreover the single carrier communication receiver obtains the channel condition information 122 of each subcarrier in the OFDM symbol and the performance number of subcarrier ontology information 124.In addition, the divider 132 of single carrier communication receiver can be with the signal value of the channel condition information 122 of each subcarrier divided by the signal value of the subcarrier ontology information 124 of each subcarrier to obtain the frequency domain equalization result 214 of each subcarrier.

In second example embodiment, eliminate frequency domain equalization error module 210 and comprise frequency domain equalization error-detecting module 212 and eliminate frequency domain equalization error module 216.Frequency domain equalization error-detecting module 212 receives the channel condition information 122 of each subcarrier, and each subcarrier is carried out a frequency domain equalization error-detecting.Described frequency domain equalization error-detecting is to come identification to meet the subcarrier of degree of depth decline feature according to the performance number of the channel condition information 122 of each subcarrier.In addition, eliminate frequency domain equalization error module 216, be coupled to frequency domain equalization error-detecting module 212 and anti-fast fourier transform processing module 150, and receive the channel condition information 122 of each subcarrier, the frequency domain equalization result 214 of each subcarrier and the sub-carrier indices value (not illustrating) that meets degree of depth decline feature that frequency domain equalization error-detecting module 212 is exported.Moreover, eliminate frequency domain equalization error module 216 according to the channel condition information of the subcarrier that meets degree of depth decline feature, the frequency domain equalization result of the subcarrier that meets degree of depth decline feature is carried out one eliminate the frequency domain equalization error.In addition, anti-fast fourier transform processing module 150 receives the output of eliminating frequency domain equalization error module 216, obtains the planisphere of time domain by anti-fast fourier transform.

In second example embodiment, frequency domain equalization error-detecting module 212 is calculated the performance number (being designated hereinafter simply as the channel condition information performance number) of the channel condition information 122 of each subcarrier in each OFDM symbol in described frequency domain equalization error-detecting, and a channel condition information power average value calculating each OFDM symbol sub-carriers.Described channel condition information power average value is that the sum total of the channel condition information performance number of all subcarriers in the OFDM symbol is divided by the sum of an OFDM symbol sub-carriers.Certainly, the mode of calculating the channel condition information power average value of subcarrier is not limited with above-mentioned, and this field has knows the knowledgeable usually, can also utilize other mode to calculate the channel condition information power average value of subcarrier.

In addition, frequency domain equalization error-detecting module 212 is also carried out a channel condition information power average value reduction to the channel condition information power average value of each OFDM symbol sub-carriers, to obtain a degree of depth decline threshold value.Described channel condition information power average value is reduced to the channel condition information power average value divided by 2 Nth power, and wherein, N is the sum of predetermined depth decline threshold value.Described degree of depth decline threshold value is that frequency domain equalization error-detecting module 212 is used for the performance number of channel condition information 122 of each subcarrier of comparison, and judges whether that according to comparative result the subcarrier that detects at present meets degree of depth decline feature.

Explanation more accurately, whether the performance number of the channel condition information 122 of frequency domain equalization error-detecting module 212 each subcarrier of inspection is less than degree of depth decline threshold value.If in the frequency domain equalization error-detecting, the channel condition information performance number that frequency domain equalization error-detecting module 212 is confirmed the present subcarrier that detects judges then that less than the degree of depth threshold value that fails the present subcarrier that checks meets degree of depth decline feature.On the contrary, if in the frequency domain equalization error-detecting, the channel condition information performance number that frequency domain equalization error-detecting module 212 is confirmed the subcarrier that detects at present judges then that more than or equal to the degree of depth threshold value that fails the present subcarrier that checks does not meet degree of depth decline feature.In addition, the mode of compute depth decay threshold value is not limited with above-mentioned, and this field has knows that usually the knowledgeable can also be multiplied by the channel condition information power average value predefined attenuation coefficient, to obtain depth attenuation's threshold value.

In second example embodiment, eliminate frequency domain equalization error module 210 also according to the channel condition information power average value of each OFDM symbol sub-carriers, calculate a plurality of reduction threshold values, and whether the channel status letter performance number that checks the subcarrier meet degree of depth decline feature is less than present reduction threshold value.As previously mentioned, the index value that meets the subcarrier of degree of depth decline feature by reception, channel condition information performance number and a plurality of reduction threshold value that 210 pairs of elimination frequency domain equalization error module meet the subcarrier of depth attenuation's feature compare, and in the middle of a plurality of reduction factors, select one of them according to result relatively, then this frequency domain equalization result who meets the subcarrier of depth attenuation's feature is multiplied by the selected reduction factor, to obtain to eliminate the result of frequency domain equalization error.The above-mentioned reduction factor is all the default reduction factor, and is stored in the buffer (not illustrating).

In second example embodiment, eliminate frequency domain equalization error module 210 and obtain above-mentioned a plurality of reduction threshold values according to following equation (2) calculating:

ATT_THD_k=20 * log ₁₀(CSI_Power_mean)-REG_k equation (2)

Wherein, a plurality of reduction threshold values add up to K, K is the positive integer more than or equal to 1, k is index value and the k=1 of a plurality of reduction threshold values, 2, ..., K, ATT_THD_k are k reduction threshold value, CSI_Power_mean is the channel condition information power average value of all subcarriers in each OFDM symbol, and REG_k is k pre-set interval spacing value.It is interval that above-mentioned a plurality of reduction threshold values form a plurality of reductions altogether, and interval each the corresponding reduction factor of each reduction, suppose to meet the channel condition information performance number of subcarrier of depth attenuation's feature smaller or equal to k reduction thresholding, but greater than k-1 reduction thresholding, then k the reduction factor can be selected, and this frequency domain equalization result who meets the subcarrier of depth attenuation's feature can be multiplied by this k the reduction factor, to obtain to eliminate the result of frequency domain equalization error.Wherein, k the reduction factor can be recognized as att_k=2 ^{-(att_factor_k)}, and att_factor_k is default numeral.

Except a kind of inhibition frequency domain equalization error system 200 for the single carrier communication receiver that above second example embodiment of introducing provides, the present invention can also utilize self adaptation adjustment mechanism to finely tune the reduction threshold value.Below will introduce the inhibition frequency domain equalization error system 300 that this comprises self adaptation adjustment mechanism fine setting reduction threshold value with Fig. 3.

Fig. 3 is the system block diagrams that the 3rd example embodiment according to the present invention illustrates a kind of inhibition frequency domain equalization error system 300 for the single carrier communication receiver.Please refer to Fig. 3, the inhibition frequency domain equalization error system 200 that the inhibition frequency domain equalization error system 300 that the 3rd example embodiment provides and second example embodiment provide is similar haply, and its difference is in suppressing frequency domain equalization error system 300 and comprises self adaptation adjustment reduction factor computing module 218.Other part identical with suppressing frequency domain equalization error system 200 please refer to above-mentioned second example embodiment and Fig. 2.

In the 3rd example embodiment, self adaptation adjustment reduction factor computing module 218 is coupled to divider 132, frequency domain equalization error-detecting module 212 and eliminates frequency domain equalization error module 210.In addition, the result of adaptation adjustment reduction factor computing module 218 reception frequency domain equalization results 214 and frequency domain equalization error-detecting (that is, and produce and adjust the reduction needed step value of threshold value (not illustrating) and give and eliminate frequency domain equalization error module 210 index value that meets the subcarrier of degree of depth decline feature).Moreover, adapt to and adjust reduction factor computing module 218 according to result and the frequency domain equalization result 214 of above-mentioned frequency domain equalization error-detecting, each subcarrier is carried out the computing of the self adaptation adjustment reduction factor to produce a step-length, eliminate frequency domain equalization error module 210 and then can use the step-length that produces to adjust aforesaid a plurality of reduction threshold value.In addition, above-mentioned calculating step-length and the mode of adjusting the reduction threshold value, will in back described inhibition frequency domain equalization error approach do further introduction.

Single carrier communication receiver of the present invention can be a receiver that uses digital ground multimedia broadcast (DTMB) standard.Yet the present invention is not limited to this, and the inhibition frequency domain equalization error system 200 for the single carrier communication receiver provided by the present invention can also be used for other single carrier communication system with inhibition frequency domain equalization error system 300.Except the above inhibition frequency domain equalization error system of introducing that is used for the single carrier communication receiver 200 and inhibition frequency domain equalization error system 300, below will introduce the inhibition frequency domain equalization error approach for the single carrier communication receiver provided by the present invention with Fig. 4 to Figure 10.

Fig. 4 is the flow chart that second example embodiment according to the present invention illustrates a kind of inhibition frequency domain equalization error approach for the single carrier communication receiver.Please refer to Fig. 2 and Fig. 4, described inhibition frequency domain equalization error approach 400 begins to carry out in step S402, continues behind the step S402 and carries out step S404.In step S404, suppress 400 pairs of each subcarriers of frequency domain equalization error approach and carry out the frequency domain equalization error-detecting.As previously mentioned, the frequency domain equalization error-detecting is that channel condition information according to each subcarrier comes identification to meet the subcarrier of degree of depth decline feature.Continue behind the step S404 and carry out step S406.In step S406, suppress frequency domain equalization error approach 400 according to the channel condition information of the subcarrier that meets degree of depth decline feature, the frequency domain equalization result of the subcarrier that meets degree of depth decline feature is eliminated the frequency domain equalization error.Continue behind the step S406 and carry out step S408, in step S408, suppress frequency domain equalization error approach 400 and finish.

Fig. 5 is that the 3rd example embodiment according to the present invention illustrates the another kind of flow chart that is used for the inhibition frequency domain equalization error approach of single carrier communication receiver.Please refer to Fig. 3 and Fig. 5, described inhibition frequency domain equalization error approach 500 begins to carry out in step S502, continues behind the step S502 and carries out step S504.Step S504 is identical with the step S404 of second example embodiment, does not hereat repeat at this.Continue behind the step S504 and carry out step S506.In step S506, suppress frequency domain equalization error approach 500 and calculate according to the power average value of the channel condition information of all subcarriers in the OFDM symbol and respectively reduce threshold value, can be with reference to the equation (2) in aforementioned second example embodiment and respectively reduce the computational methods of threshold value.Continue behind the step S506 and carry out step S508.In step S506,500 pairs of inhibition frequency domain equalization error approach are respectively reduced threshold value and are carried out the self adaptation adjustment.Described self adaptation is adjusted into result and the frequency domain equalization result of frequency domain equalization error-detecting, and each subcarrier is carried out the computing of self adaptation adjustment reduction factor producing a step-length, and the step-length that produces can be used to adjust and respectively reduces threshold value.The threshold value of respectively reducing after the self adaptation adjustment adjustment deducts described step-length for the threshold value of respectively reducing originally.Continue behind the step S508 and carry out step S510.

In step S510, suppress frequency domain equalization error approach 500 according to the channel status letter performance number of the subcarrier that meets degree of depth decline feature and the above-mentioned trained threshold value of respectively reducing, select the suitable reduction factor.Continue behind the step S510 and carry out step S512.In step S512, suppress frequency domain equalization error approach 500 is adjusted the subcarrier that meets degree of depth decline feature according to the reduction factor of selecting frequency domain equalization result.Continue behind the step S512 and carry out step S516, in step S514, suppress frequency domain equalization error approach 500 and finish.

Fig. 6 is the flow chart that the 3rd example embodiment according to the present invention illustrates a kind of identification frequency domain equalization error approach for the single carrier communication receiver.Please refer to Fig. 3, Fig. 5 and Fig. 6, identification frequency domain equalization error approach 600 is the thin portion flow process that the 3rd example embodiment frequency domain balancing error detects (and the step S504 among Fig. 5).At first, identification frequency domain equalization error approach 600 begins to carry out in step S602, continues behind the step S602 and carries out step S604.In step S604, identification frequency domain equalization error approach 600 is calculated the performance number of the channel condition information of each subcarrier in the OFDM symbol.Continue behind the step S604 and carry out step S606.In step S606, the mean value of the performance number of the channel condition information of an OFDM symbol sub-carriers of identification frequency domain equalization error approach 600 calculating (that is, the channel condition information power average value).Described channel condition information power average value is that the sum total of channel condition information 122 performance numbers of all subcarriers in the OFDM symbol is divided by the sum of an OFDM symbol sub-carriers.Certainly, as noted earlier, the mode of calculating the channel condition information power average value is not limited in above-mentioned mode.

Continue behind the step S606 and carry out step S608.In step S608, the channel condition information power average value of 600 pairs of each OFDM symbol sub-carriers of identification frequency domain equalization error approach is carried out a channel condition information power average value reduction, to obtain a degree of depth decline threshold value.Described channel condition information power average value is reduced to the channel condition information power average value divided by 2 Nth power, and wherein, N is the scale factor order of predetermined depth decline threshold value.In other words, obtain degree of depth decline threshold value, need only N the position that move to right with the channel condition information power average value.In addition, be noted that the mode that obtains degree of depth decline threshold value is not limited with above-mentioned example.Continue behind the step S608 and carry out step S610.

In step S610, whether the sub-carrier channels state information performance number in OFDM symbol of identification frequency domain equalization error approach 600 inspections is less than the degree of depth decline threshold value of having reduced.If then continue behind the step S610 and carry out step S612.If not, then continue behind the step S610 and carry out step S614.In step S612, identification frequency domain equalization error approach 600 confirms that the channel condition information of the present subcarrier that checks of the present subcarrier that checks meets degree of depth decline feature.On the contrary, in step S614, identification frequency domain equalization error approach 600 confirms that the channel condition information of the present subcarrier that checks does not meet degree of depth decline feature.Behind the step S612 or behind the step S614, continue and carry out step S616, in step S616, identification frequency domain equalization error approach 600 finishes.

Fig. 7 is the flow chart that the 3rd example embodiment according to the present invention illustrates a kind of elimination frequency domain equalization error approach for the single carrier communication receiver.Please refer to Fig. 3, Fig. 5 and Fig. 6, eliminating frequency domain equalization error approach 700 is the thin portion flow process of the step S512 of Fig. 5.Eliminate frequency domain equalization error approach 700 and begin to carry out in step S702, continue behind the step S702 and carry out step S704.In step S704, eliminate frequency domain equalization error approach 700 and calculate a plurality of reduction threshold values according to the channel condition information power average value of an OFDM symbol sub-carriers.Continue behind the step S704 and carry out step S706.

In step S706, channel condition information performance number and a plurality of reduction threshold value that 700 pairs of elimination frequency domain equalization error approach meet the subcarrier of degree of depth decline feature compare, to select one of them in the corresponding a plurality of reduction factors of the interval institute of the reduction that forms from a plurality of reduction threshold values.Be noted that K reduction threshold value forms K+1 and reduce the interval, each reduction is interval can one of correspondence to reduce the factor, and this reduction factor att_k is example with k interval) equal 2 ^{-att_factor_k}, wherein att_factor_k is k interval default numerical value.Then, behind step S706, carry out step S708.In step S708, the frequency domain equalization result who meets the subcarrier of degree of depth decline feature at present is multiplied by the reduction factor of this selection, obtaining the eliminating frequency domain equalization error result, that is div_out '=div_out/2 ^Att_factor_kBehind the step S708, continue and carry out step S710, in step S710, eliminate frequency domain equalization error approach 700 and finish.

Please continue with reference to Fig. 7, in the decline degree of depth and all relevant property of carrier-to-noise ratio of the channel condition information of this reason that is noted that channel condition information performance number with subcarrier is divided into a plurality of intervals size that is the frequency domain equalization error amount and each subcarrier.Illustrate, when carrier-to-noise ratio was certain value, if the decline of experiencing is more dark, then the frequency domain equalization error amount can be more big.When the decline of experiencing was certain value, if carrier-to-noise ratio is more big, then the frequency domain equalization error amount can be more little.Therefore, when eliminating the frequency domain equalization error approach, the reduction that need carry out in various degree the frequency domain equalization result of the subcarrier of experience different channels state information performance number decline is handled.In other words, to channel condition information performance number decline more dark the frequency domain equalization result of subcarrier should be multiplied by the bigger reduction factor of attenuation (that is the numerical value of the reduction factor needs smaller).In addition, be noted that above-mentioned method if be used for the DTMB system, then K got 4 o'clock, just can obtain good result.Then, below will be further described above-mentioned elimination frequency domain equalization error approach with Fig. 8 and Fig. 9.

Fig. 8 is the flow chart that the 4th example embodiment according to the present invention illustrates a kind of elimination frequency domain equalization error approach for the single carrier communication receiver.In the 4th demonstration example, it is similar with elimination frequency domain equalization error approach 700 shown in Figure 7 to eliminate frequency domain equalization error approach 800, but default reduction threshold value is 4, is respectively the first reduction threshold value, the second reduction threshold value, the 3rd reduction threshold value and the 4th reduction threshold value.Because the step S702 of step S802 and step S804 and Fig. 7 and step S704 are similar, so do not repeat at this.Behind the step S804, continue and carry out step S806.In step S806, eliminate frequency domain equalization error approach 800 and check that whether the channel condition information performance number of a subcarrier is more than or equal to the first reduction threshold value.If then behind the step S806, continue and carry out step S808.If not, then behind the step S806, continue and carry out step S810.In step S808, elimination frequency domain equalization error approach 800 is multiplied by the first reduction factor with the frequency domain equalization result of the present subcarrier that checks.Behind the step S808, continue and carry out step S824.

In step S810, whether eliminate the frequency domain equalization error approach 800 further channel condition information performance numbers that check a subcarrier more than or equal to the second reduction threshold value, and the second reduction threshold value should be littler than the first reduction threshold value.If then behind the step S810, continue and carry out step S812.If not, then behind the step S810, continue and carry out step S814.In step S812, the frequency domain equalization result of the present subcarrier that checks is multiplied by the second reduction factor, and the attenuation of the second reduction factor should be bigger than the first reduction factor.Behind the step S812, continue and carry out step S824.

In step S814, whether eliminate the frequency domain equalization error approach 800 further channel condition information performance numbers that check a subcarrier more than or equal to the 3rd reduction threshold value, and the 3rd reduction threshold value should be littler than the second reduction threshold value.If then behind the step S814, continue and carry out step S816.If not, then behind the step S814, continue and carry out step S818.In step S816, elimination frequency domain equalization error approach 800 is multiplied by the 3rd reduction factor with the frequency domain equalization result of the present subcarrier that checks, and the attenuation of the 3rd reduction factor should be bigger than the second reduction factor.Behind the step S816, continue and carry out step S824.In step S818, whether eliminate the frequency domain equalization error approach 800 further channel condition information performance numbers that check a subcarrier more than or equal to the 4th reduction threshold value, and the 4th reduction threshold value should be littler than the 3rd reduction threshold value.If then behind the step S818, continue and carry out step S820.If not, then behind the step S818, continue and carry out step S822.In step S820, elimination frequency domain equalization error approach 800 is multiplied by the 4th reduction factor with the frequency domain equalization result of the present subcarrier that checks, and the attenuation of the 4th reduction factor should be bigger than the 3rd reduction factor.Behind the step S820, continue and carry out step S824.In step S822, elimination frequency domain equalization error approach 800 is multiplied by the 5th reduction factor with the frequency domain equalization result of the present subcarrier that checks, and the attenuation of the 5th reduction factor should be bigger than the 4th reduction factor.Behind the step S818, continue and carry out step S824.In step S824, eliminate frequency domain equalization error approach 800 and finish.

Fig. 9 is that the 4th example embodiment according to the present invention illustrates a kind of schematic diagram that reduces factor method for selecting of single carrier communication receiver.Please be simultaneously with reference to Fig. 8 and Fig. 9, in Fig. 9, the longitudinal axis is channel fading value (unit is decibel), and transverse axis is the sub-carrier indices value, but only illustrate the part subcarrier of an OFDM symbol among Fig. 9.Four reduction threshold values are arranged in Fig. 9, be respectively the first reduction threshold value 902, the second reduction threshold value 904, the 3rd reduction threshold value 906 and the 4th reduction threshold value 908.Show five reduction thresholding intervals on the right side of Fig. 9, be respectively interval the 918 and the 5th reduction interval 920 of interval the 916, the 4th reduction of interval the 914, the 3rd reduction of interval 912, second reduction of first reduction.When the channel condition information performance number of subcarrier during more than or equal to the first reduction threshold value 902, namely drop on interval 912 o'clock of first reduction, select and reduce factor method 900 and can select first and reduce the factor in order to eliminate the frequency domain equalization error.When the channel condition information performance number of subcarrier is reduced threshold value 904 less than the first reduction threshold value 902 and more than or equal to second, namely drop on interval 914 o'clock of second reduction, select and reduce factor method 900 and can select second and reduce the factor in order to eliminate the frequency domain equalization error.The rest may be inferred, to drop on interval the 918 and the 5th reduction of interval the 916, the 4th reduction of the 3rd reduction interval 920 the time when the channel condition information performance number of subcarrier, selects to reduce factor method 900 and can select the 3rd respectively and reduce the factor, the 4th and reduce the factor and the 5th and reduce the factor with elimination frequency domain equalization error.Above-mentioned only is an example embodiment, be not in order to limiting the present invention, and the number of the operable reduction threshold value of other embodiments of the invention can be different from four, but in the DTMB system, if getting the number of reduction threshold value is 4, just can obtain good effect.

Figure 10 is the flow chart that the 3rd example embodiment according to the present invention illustrates a kind of self adaptation adjustment reduction threshold value method.Self adaptation adjustment reduction threshold value method 1000 is the frequency domain equalization mean value of performance number as a result that utilizes a plurality of OFDM symbols, and the degree of depth of a plurality of OFDM symbols decline frequency domain equalization as a result the mean value of performance number come dynamic adjustment reduction threshold value.In other words, self adaptation adjustment reduction threshold value method 1000 utilizes on the time orientation statistical value in several OFDM symbols recently to finely tune the reduction threshold value.Please be simultaneously with reference to Fig. 3 and Figure 10, self adaptation adjustment reduction threshold value method 1000 starts from step S1002, continues to carry out step S1004 behind the step S1002.In step S1004, self adaptation adjustment reduction threshold value method 1000 is at first calculated in the OFDM symbol, and a frequency domain equalization of each subcarrier is performance number as a result.Behind the step S1004, continue to carry out step S1006.In step S1006, self adaptation adjustment reduction threshold value method 1000 on time orientation, to the frequency domain equalization of a plurality of OFDM symbols as a result performance number carry out low-pass filtering treatment, and obtain a plurality of frequency domain equalization low-pass filtering results.Behind the step S1006, continue to carry out step S1008.In step S1008, self adaptation adjustment reduction threshold value method 1000 on time orientation, calculate a plurality of OFDM symbols the frequency domain equalization mean value of performance number after low-pass filtering as a result, that is frequency domain equalization average power content as a result.Behind the step S1008, continue to carry out step S1010.

In step S1010, self adaptation adjustment reduction threshold value method 1000 is calculated on time orientation, the degree of depth decline frequency domain equalization mean value of performance number as a result that meets the subcarrier of degree of depth decline feature in a plurality of OFDM symbols, that is degree of depth decline frequency domain equalization power average value as a result.Behind the step S1010, continue to carry out step S1012.In step S1012, self adaptation adjustment reduction threshold value method 1000 according to frequency domain equalization as a result power average value and degree of depth decline frequency domain equalization as a result power average value calculate to adjust the step-length of reduction threshold value.Being used for adjusting the step-length of reducing threshold value can and obtain according to following equation (3) calculating:

Equation (3)

, wherein, λ is step-length, div_out_deep_fading_powermean is frequency domain equalization power average value as a result, and div_out_power_mean is degree of depth decline frequency domain equalization power average value as a result.Behind the step S1010, continue to carry out step S1012.

In step S1014, adapt to adjust reduction threshold value method 1000 and adjust according to the step-length that calculates and respectively reduce threshold value.The threshold value of respectively reducing after the adjustment deducts the above-mentioned step-length that obtains as calculated for the threshold value of respectively reducing originally.Behind the step S1014, continue and carry out step S1016, in step S1016, eliminate frequency domain equalization error approach 1000 and finish.

Figure 11 is that the 3rd example embodiment illustrate according to the present invention is through the schematic diagram of self adaptation adjustment reduction threshold value.Please refer to Figure 11, Figure 11 and Fig. 9 are similar, but have increased the reduction threshold value boundary after four adjustment newly.Originally the first reduction threshold value 902, the second reduction threshold value 904, the 3rd reduction threshold value 906 and the 4th reduction threshold value 908 are adjusted to the first reduction threshold value 1102, the second reduction threshold value 1104, the 3rd reduction threshold value 1106 and the 4th reduction threshold value 1108 respectively.The amplitude adjusted of reduction threshold value can be with reference to the adjustment step-length 1112,1114 shown in Figure 11 right side, and adjusts step-length 1112, the 1114th, via adaptation adjustment reduction threshold value method 1000 shown in Figure 10 calculate and.

Figure 12 is according to the schematic diagram of performance number as a result of frequency domain equalization before the 3rd low-pass filtering that example embodiment illustrates of the present invention.Please refer to Figure 10 and Figure 12, the frequency domain equalization of each subcarrier shown in Figure 12 performance number as a result is the preceding frequency domain equalization handled of step S1006 shown in Figure 10 performance number as a result.Figure 13 is according to the schematic diagram of performance number as a result of frequency domain equalization after the 3rd low-pass filtering that example embodiment illustrates of the present invention.Please refer to Figure 10 and Figure 13, the frequency domain equalization of each subcarrier shown in Figure 13 as a result performance number be step S1006 shown in Figure 10 handle after frequency domain equalization performance number as a result.When Figure 12 and Figure 13 compared, the frequency domain equalization that can obviously find out each subcarrier after the low-pass filtering difference between the performance number as a result comparatively reduced.Figure 14 is that the 3rd example embodiment according to the present invention illustrates and eliminates behind the balancing error frequency domain equalization schematic diagram of performance number as a result.Please refer to Fig. 5, Figure 13 and Figure 14, the frequency domain equalization of each subcarrier shown in Figure 13 performance number as a result is not handle through step S512 as yet but through the performance number as a result of the frequency domain equalization after the low-pass filtering treatment, and the frequency domain equalization of each subcarrier shown in Figure 14 as a result performance number be the performance number as a result of the frequency domain equalization after handling through step S512.In other words, frequency domain equalization shown in Figure 14 as a result performance number for through eliminating the frequency domain equalization performance number as a result after the frequency domain equalization error.When Figure 13 and Figure 14 compare, can obviously see after the elimination frequency domain equalization error among Figure 14 frequency domain equalization as a result the difference between the performance number more reduce.The frequency domain equalization of above Figure 12, Figure 13 and Figure 14 performance number as a result is all that to adopt 16-QAM modulation schemes and code check be the result who carries out under 0.4 the environment after the emulation.

Figure 15 is that the 3rd example embodiment according to the present invention illustrates the systematic function curve chart of eliminating single carrier communication receiver before the balancing error.Figure 16 is that the 3rd example embodiment according to the present invention illustrates the systematic function curve chart of eliminating single carrier communication receiver behind the balancing error.The longitudinal axis of Figure 15 and Figure 16 is bit error rate (Biterror rate), and transverse axis is carrier-to-noise ratio (Carrier-to-noise ratio), and unit is decibel.Systematic function curve 1502 shown in Figure 15, systematic function curve 1504 and systematic function curve 1506 are respectively when code check is 0.4, code check is 0.6 when being 0.8 with code check, use the 64-QAM modulation tech, and channel circumstance is the result after the emulation under the upright decline of thunder channel (the Rayleigh fading channel) situation.Systematic function curve 1602 shown in Figure 16, systematic function curve 1604 and systematic function curve 1606 correspond to systematic function curve 1502, the systematic function curve 1504 and systematic function curve 1506 among Figure 15, and are the performance curve after the processing of process elimination balancing error.In addition, when comparing Figure 15 and Figure 16, can find out obviously under identical channel circumstance situation that the systematic function of single carrier communication receiver improves about 2 decibels at least behind the elimination balancing error.

In sum, according to a plurality of example embodiment of the present invention, the invention provides the inhibition frequency domain equalization error approach and the system thereof that are used in the single carrier communication receiver.Described inhibition frequency domain equalization error approach and system thereof come identification to meet the subcarrier of degree of depth decline feature according to the channel condition information of each subcarrier.In addition, meet the channel condition information of the subcarrier of degree of depth decline feature a bit according to this, the frequency domain equalization result of the subcarrier that meets degree of depth decline feature that picks out is to some extent eliminated the frequency domain equalization error.In addition, the method for the above-mentioned elimination frequency domain equalization error reduction factor of also using the computing of the self adaptation adjustment reduction factor to produce suppresses the frequency domain equalization error of each subcarrier.Accordingly, described inhibition frequency domain equalization error approach and system thereof can increase substantially the single carrier communication receiver the frequency domain equalization performance, simplify the circuit complexity of single carrier communication receiver, and and then reduce the circuit production cost of single carrier communication receiver.

Though disclose as above with example embodiment; so it is not in order to limit embodiment of the present invention; have in the technical field under any and know the knowledgeable usually; not breaking away from the spirit and scope of the embodiment that discloses; when doing a little change and retouching, so protection range is worked as with being as the criterion that claim was defined.

Claims (17)

1. one kind is suppressed the frequency domain equalization error approach, be applicable at a frequency domain and carry out the single carrier communication receiver that signal recovers, wherein, this single carrier communication receiver receives a plurality of subcarriers, and this single carrier communication receiver obtains a channel condition information and a sub-carrier power value of each subcarrier at this frequency domain by a fast fourier transform, and with this channel condition information of each subcarrier divided by this sub-carrier power value of each subcarrier to obtain a frequency domain equalization result of each subcarrier, it is characterized in that this inhibition frequency domain equalization error approach comprises:

Each subcarrier is carried out a frequency domain equalization error-detecting, this frequency domain equalization error-detecting is that this channel condition information according to each subcarrier comes identification to meet the subcarrier of degree of depth decline feature, and the step of frequency domain equalization error-detecting comprises: a channel condition information performance number of calculating each subcarrier; Calculate the channel condition information power average value of described subcarrier, wherein, a summation of the channel condition information performance number that this channel condition information power average value is each subcarrier is divided by a sum of subcarrier; And

According to this channel condition information of each subcarrier that meets this degree of depth decline feature, the frequency domain equalization result of each subcarrier of meeting this degree of depth decline feature is carried out one eliminate the frequency domain equalization error, wherein, this elimination frequency domain equalization error comprises:

According to the channel condition information power average value of described subcarrier, calculate a plurality of reduction threshold values;

This channel condition information performance number and a plurality of reduction threshold value to the subcarrier that meets this degree of depth decline feature compare, and select one of them from the corresponding a plurality of reduction factors in a plurality of reductions interval that these a plurality of reduction threshold values form; And

This frequency domain equalization result who meets each subcarrier of this degree of depth decline feature at present is multiplied by selected this reduction factor, obtaining the result of this elimination frequency domain equalization error,

Wherein, these a plurality of reduction threshold values are that a power decibel value by this channel condition information power average value deducts a plurality of pre-set interval spacing values respectively and gets.

2. inhibition frequency domain equalization error approach as claimed in claim 1 is characterized in that the step of each subcarrier being carried out this frequency domain equalization error-detecting also comprises:

This channel condition information power average value of described subcarrier is carried out channel condition information power average value reduction, to obtain degree of depth decline threshold value; And

Whether check this channel condition information performance number of each subcarrier less than this degree of depth decline threshold value, wherein,

If this channel condition information performance number, confirms then that this subcarrier that checks at present meets this degree of depth decline feature less than this degree of depth decline threshold value; And

If this channel condition information performance number, confirms then that this subcarrier that checks does not at present meet this degree of depth decline feature more than or equal to this degree of depth decline threshold value.

3. inhibition frequency domain equalization error approach as claimed in claim 2, wherein, this degree of depth decline threshold value equals this channel condition information power average value toward moving right N result.

4. inhibition frequency domain equalization error approach as claimed in claim 1 is characterized in that these a plurality of reduction threshold values obtain for calculating according to following equation (1):

ATT_THD_k=20 * log ₁₀(CSI_Power_mean)-REG_k equation (1)

Wherein, one of these a plurality of reduction threshold values add up to K, and K is the positive integer more than or equal to 1, and k is an index value and the k=1 of these a plurality of reduction threshold values, 2,, K, ATT_THD_k are k reduction threshold value, CSI_Power_mean is this channel condition information power average value of described subcarrier, and REG_k is k pre-set interval spacing value.

5. inhibition frequency domain equalization error approach as claimed in claim 1 is characterized in that this inhibition frequency domain equalization error approach more comprises:

Result and this frequency domain equalization result according to this frequency domain equalization error-detecting, the subcarrier that respectively meets this degree of depth decline feature is carried out the computing of the self adaptation adjustment reduction factor to produce a step-length, wherein, this elimination frequency domain equalization error uses this step-length to adjust the required a plurality of reduction threshold values of this elimination frequency domain equalization error; And

The result of this elimination frequency domain equalization error is obtained a planisphere of a time domain by an anti-fast fourier transform.

6. inhibition frequency domain equalization error approach as claimed in claim 5 is characterized in that this self adaptation adjustment reduction factor computing comprises:

Calculate this frequency domain equalization result's of each subcarrier frequency domain equalization performance number as a result;

On a time direction, to this frequency domain equalization result's of each subcarrier frequency domain equalization as a result performance number carry out a low-pass filtering treatment, and obtain a plurality of frequency domain equalization low-pass filtering results;

According to these a plurality of frequency domain equalization low-pass filtering results, calculate frequency domain equalization mean value as a result, wherein, this frequency domain equalization mean value as a result is these a plurality of frequency domain equalization low-pass filtering results' a mean value;

Frequency domain equalization result according to each subcarrier that meets degree of depth decline feature, calculate degree of depth decline frequency domain equalization mean value as a result, wherein, this degree of depth decline frequency domain equalization as a result mean value be frequency domain equalization result's a mean value that meets each subcarrier of degree of depth decline feature;

According to this frequency domain equalization mean value and this degree of depth decline as a result frequency domain equalization mean value as a result, calculate this step-length of adjusting these a plurality of reduction threshold values; And

Adjust according to this step-length that calculates and respectively to reduce threshold value, wherein, the threshold value of respectively reducing after the adjustment deducts this step-length for originally respectively reducing threshold value.

7. inhibition frequency domain equalization error approach as claimed in claim 6, this step-length of it is characterized in that these a plurality of reduction threshold values obtains for calculating according to following equation (2):

, wherein, λ is this step-length, div_out_deep_fading_power_mean is this frequency domain equalization mean value as a result, and div_out_power_mean is this degree of depth decline frequency domain equalization mean value as a result.

8. inhibition frequency domain equalization error approach as claimed in claim 1 is characterized in that this single carrier communication receiver is for using the receiver of digital ground multimedia broadcast standard.

9. one kind is suppressed the frequency domain equalization error system, be applicable at a frequency domain and carry out the single carrier communication receiver that signal recovers, wherein, this single carrier communication receiver receives a plurality of subcarriers, and this single carrier communication receiver obtains a channel condition information and a sub-carrier power value of each subcarrier at this frequency domain by a fast fourier transform, and with this channel condition information of each subcarrier divided by this sub-carrier power value of each subcarrier to obtain a frequency domain equalization result of each subcarrier, it is characterized in that this inhibition frequency domain equalization error system comprises:

One frequency domain equalization error-detecting module, each subcarrier is carried out a frequency domain equalization error-detecting, this frequency domain equalization error-detecting is that this channel condition information according to each subcarrier comes identification to meet the subcarrier of degree of depth decline feature, this frequency domain equalization error-detecting module is calculated a channel condition information performance number of each subcarrier in this frequency domain equalization error-detecting, calculate the channel condition information power average value of described subcarrier, wherein, a summation of this channel condition information power average value channel condition information performance number that is each subcarrier is divided by a sum of subcarrier; And

One eliminates the frequency domain equalization error module, and according to this channel condition information of each subcarrier that meets this degree of depth decline feature, this frequency domain equalization result of each subcarrier of meeting this degree of depth decline feature is carried out one eliminate the frequency domain equalization error, wherein,

This eliminates the frequency domain equalization error module according to a channel condition information power average value of described subcarrier, calculates a plurality of reduction threshold values;

This elimination frequency domain equalization error module compares this channel condition information performance number and a plurality of reduction threshold value of each subcarrier of meeting this degree of depth decline feature, and selects one of them from the corresponding a plurality of reduction factors in a plurality of reductions interval that these a plurality of reduction threshold values form; And

This frequency domain equalization result that this elimination frequency domain equalization error module will meet each subcarrier of this degree of depth decline feature at present is multiplied by selected this reduction factor, obtaining the result of this elimination frequency domain equalization error,

Wherein, these a plurality of reduction threshold values are that a power decibel value by this channel condition information power average value really removes a plurality of pre-set interval spacing values respectively and gets.

10. inhibition frequency domain equalization error system as claimed in claim 9 is characterized in that:

This frequency domain equalization error-detecting module is carried out channel condition information power average value reduction to this channel condition information power average value of described subcarrier, to obtain degree of depth decline threshold value; And

Whether this channel condition information performance number of this each subcarrier of frequency domain equalization error-detecting module check less than this degree of depth decline threshold value, wherein,

If in this frequency domain equalization error-detecting, this frequency domain equalization error-detecting module is confirmed this channel condition information performance number less than this degree of depth decline threshold value, and then this frequency domain equalization error-detecting module judges that this subcarrier that checks at present meets this degree of depth decline feature; And

If in this frequency domain equalization error-detecting, this frequency domain equalization error-detecting module is confirmed this channel condition information performance number more than or equal to this degree of depth decline threshold value, and then this frequency domain equalization error-detecting module judges that this subcarrier that checks does not at present meet this degree of depth decline feature.

11. inhibition frequency domain equalization error system as claimed in claim 10 is characterized in that this degree of depth decline threshold value equals this channel condition information power average value toward the result of N the position that move right.

12. inhibition frequency domain equalization error system as claimed in claim 9 is characterized in that:

The result that this elimination frequency domain equalization error module will be eliminated the frequency domain equalization error obtains a planisphere of a time domain by an anti-fast fourier transform.

13. inhibition frequency domain equalization error system as claimed in claim 12 is characterized in that this elimination frequency domain equalization error module obtains these a plurality of reduction threshold values according to following equation (1) calculating:

ATT_THD_k=20 * log ₁₀(CSI_POWcr_mcan)-REG_k equation (1)

Wherein, one of these a plurality of reduction threshold values add up to K, and K is the positive integer more than or equal to 1, and k is an index value and the k=1 of those a plurality of reduction threshold values, 2,, K, ATT_THD_k are k reduction threshold value, CSI_Power_mean is this channel condition information power average value of subcarrier described in each quadrature stroke rate multitask symbol, and REG_k is k pre-set interval spacing value.

14. inhibition frequency domain equalization error system as claimed in claim 9 is characterized in that this inhibition frequency domain equalization error system more comprises:

One self adaptation adjustment reduction factor computing module, result and this frequency domain equalization result according to this frequency domain equalization error-detecting, each subcarrier is carried out the computing of the self adaptation adjustment reduction factor to produce a step-length, wherein, this elimination frequency domain equalization error uses this step-length to adjust the required a plurality of reduction threshold values of this elimination frequency domain equalization error.

15. inhibition frequency domain equalization error system as claimed in claim 14 is characterized in that:

This self adaptation adjustment reduction factor computing module calculates this frequency domain equalization result's of each subcarrier frequency domain equalization performance number as a result;

This self adaptation adjustment reduction factor computing module on a time direction to this frequency domain equalization result's of each subcarrier frequency domain equalization as a result performance number carry out a low-pass filtering treatment, and obtain a plurality of frequency domain equalization low-pass filtering results;

This self adaptation adjustment reduction factor computing module calculates frequency domain equalization mean value as a result according to these a plurality of frequency domain equalization low-pass filtering results, and wherein, this frequency domain equalization mean value as a result is these a plurality of frequency domain equalization low-pass filtering results' a mean value;

This self adaptation adjustment reduction factor computing module is according to the frequency domain equalization result of each subcarrier that meets degree of depth decline feature, calculate degree of depth decline frequency domain equalization mean value as a result, wherein, this degree of depth decline frequency domain equalization as a result mean value be frequency domain equalization result's a mean value that meets each subcarrier of degree of depth decline feature; And

This self adaptation adjustment reduction factor computing module is according to this frequency domain equalization mean value and this degree of depth frequency domain equalization mean value as a result that fails as a result, calculate this step-length of adjusting these a plurality of reduction threshold values, and adjust according to this step-length that calculates and respectively to reduce threshold value, wherein, the threshold value of respectively reducing after the adjustment deducts this step-length for originally respectively reducing threshold value.

16. inhibition frequency domain equalization error system as claimed in claim 15 is characterized in that this self adaptation adjustment reduction factor computing module obtains this step-length of these a plurality of reduction threshold values according to following equation (2) calculating:

, wherein, λ is this step-length, div_out_deep_fading_power_mean is this frequency domain equalization mean value as a result, and div_out_power_mean is this degree of depth decline frequency domain equalization mean value as a result.

17. inhibition frequency domain equalization error system as claimed in claim 9 is characterized in that this single carrier communication receiver is for using the receiver of digital ground multimedia broadcast standard.

Images