CN101911557A - Reception processing method and reception device - Google Patents

Abstract

A reception device has the frequency outside the frequency band sandwiched between the highest frequency and the lowest frequency among the frequencies of subcarriers belonging to a first subcarrier group to which known signals are transmitted, respectively, performs a control of lowering the reliability of the signal after propagation path compensation for a first subcarrier belonging to a second subcarrier group to which the data signals to which propagation path compensation is applied on the basis of the known signals are transmitted, respectively than the reliability of the signal after propagation path compensation for a second subcarrier having the frequency inside the frequency band and belonging to the second subcarrier group, and corrects an error in the signal after the propagation path compensation for the first and second subcarriers.

Description

Receiving handling method and receiving system

Technical field

The present invention relates to receiving handling method and receiving system.The present invention for example can be used in OFDM (Orthogonal Frequency Division Multiplexing, OFDM) and in the multi-carrier communication of OFDMA (Orthogonal Frequency Division Multiplexing Access, orthogonal frequency division multiplexing multiple access) etc.

Background technology

In radio communication, the signal that sends from transmitter arrives receiver through too much bar propagation path (multipath).Therefore, the signal that observes in receiver sometimes has been subjected to the influence of multipath fading, becomes the waveform of amplitude or phase distortion.About one of the means of proofreading and correct this distortion synchronous detection is arranged, it has adopted signal known between transmitter and receiver is pilot signal (being also referred to as reference signal).

In the wireless communication system that carries out synchronous detection, from the transmitter pilot signal transmitted, in receiver, use this known received signal to estimate (channel estimating) propagation path response (propagation path value), use this propagation path estimated value to carry out the propagation path compensation of data-signal.Therefore, when the error of propagation path estimated value is big, will the propagation path compensation of data-signal be impacted, and cause the error rate of data-signal to increase.

In addition, a kind of as in recent years wireless communication system, the known system that has the OFDM that can realize higher frequency utilization efficient and OFDMA etc. to carry out multi-carrier transmission.

OFDM (or OFDMA) is to use the subcarrier of a plurality of quadratures to come the technology of transmission signals.In OFDM, generate the propagation path estimated value according to each subcarrier, at the data-signal that is mapped to subcarrier, use this propagation path estimated value to carry out the propagation path compensation (equilibrium) of data-signal.

For example, in the receiver of OFDM (below be also referred to as the OFDM receiver), from received signal, detect the significant character composition, should detect timing and be made as FFT (Fast FourierTransform, fast fourier transform) regularly, significant character being carried out FFT handles.Thus, received signal is converted to the signal of frequency domain from time domain.

Detect pilot signal (subcarrier that is shone upon) the frequency-region signal of OFDM receiver after this FFT handles, use this pilot signal to carry out propagation path and estimate the propagation path compensation of the line data signal of going forward side by side.

Then, the data-signal of OFDM receiver after for described propagation path compensation, for example obtain the log-likelihood ratio (LLR:Log Likelihood Ratio) of one of reliability information as the received signal symbol that uses in error correction, symbol carries out error correction to use this information to come to received signal.

Here, when transmission environment was multi-path environment, owing to frequency selective fading, the phase place of propagation path estimated value was different because of each subcarrier with amplitude usually.In following patent documentation 1, about the big situation of multidiameter propagation, pointed out that the decline change between the adjacent sub-carrier increases, in this case, the weighting of the log-likelihood ratio (LLR) of reception data that can be by weakening this subcarrier improves the effect of error correction.

Patent documentation 1: No. 3594828 communique of Japan Patent

In above-mentioned prior art, do not consider following situation, promptly, (for example in communication band, there is following subcarrier, communication band end and near subcarrier thereof), the pilot signal quantity that these subcarriers can be used to ask for the propagation path estimated value is lacked than other subcarrier, and the precision of resulting propagation path estimated value is compared the easier deterioration of other subcarrier.

Summary of the invention

One of purpose of the present invention is, considers the existence of this sub-carrier and improves the error rate characteristic of received signal.

In addition, be not limited to aforementioned purpose, another object of the present invention is, realizes that by the action effect that each structure derived shown in the best mode that is used to carry out an invention of narration in the back be the action effect that prior art can not obtain.

For example, adopt following scheme.

(1) can adopt a kind of receiving handling method, in the receiving handling method of the receiving system corresponding with multicarrier, this receiving system receives the 1st sub carrier group and the 2nd sub carrier group, the 1st sub carrier group is corresponding to a plurality of subcarriers that send the known signal be used to obtain the propagation path estimated value respectively, the 2nd sub carrier group is corresponding to sending a plurality of subcarriers of having implemented the data-signal of propagation path compensation according to the propagation path estimated value of using described known signal to obtain respectively, described receiving handling method is characterised in that, may further comprise the steps: control, make about the reliability of signals after the propagation path compensation of the 1st subcarrier, lower than the reliability of signals after the relevant propagation path compensation of the 2nd subcarrier, described the 1st subcarrier has highest frequency in the frequency that is sandwiched in the subcarrier that belongs to described the 1st sub carrier group and the frequency the frequency band between the low-limit frequency, and belong to described the 2nd sub carrier group, described the 2nd subcarrier has the frequency in this frequency band, and belong to described the 2nd sub carrier group, based on the reliability of having carried out described control, carry out correction process for the signal after the propagation path compensation of relevant described the 1st subcarrier and described the 2nd subcarrier.

(2) and, also can adopt a kind of receiving handling method: according to the known received signal in the scheduled communication frequency band, generate the propagation path estimated value of each subcarrier, use described propagation path estimated value, the reception data-signal that is mapped to any subcarrier is carried out propagation path compensation, obtain the reliability information of the described reception data-signal after the described propagation path compensation, be weighted control, the subcarrier that lacks than other subcarrier for the quantity of the described known received signal that is used to ask for described propagation path estimated value, the weight that makes the reliability information that obtains about these subcarriers is littler than the weight of the reliability information that obtains about other subcarrier, uses the reliability information after the described weighting control to carry out the error correction of described reception data-signal.

(3) wherein, the object of described weighting control can be the reliability information that obtains at the subcarrier of the end of described communication band or this subcarrier and near subcarrier thereof.

(4) and, described weighting control can be following control: with the approaching subcarrier of subcarrier of the end of described communication band, make its weight more little.

(5) in addition, described weighting control can be following control: with the approaching sub carrier group of subcarrier of the end of described communication band, make its weight more little.

(6) wherein, can control sub-carrier number according to the measurement result of the multidiameter propagation of received signal as the object of described weighting control.

(7) in addition, can be controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the multidiameter propagation of received signal.

(8) and, can be controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the reception quality information of received signal.

(9) in addition, under the time dependent situation of the subcarrier that described known received signal is shone upon, can be according to mapping status separately, control is as the either party or the both sides of the subcarrier of the object of described weighting control and the weight coefficient that uses in described weighting control.

(10) and, when in described communication band, existing under the situation of a plurality of sub carrier group, implement described weighting control according to described sub carrier group across the one or more subcarriers that do not send.

(11) in addition, can adopt a kind of receiving system, in the receiving system corresponding with multicarrier, this receiving system receives the 1st sub carrier group and the 2nd sub carrier group, the 1st sub carrier group is corresponding to a plurality of subcarriers that send the known signal be used to obtain the propagation path estimated value respectively, the 2nd sub carrier group is corresponding to sending a plurality of subcarriers of having implemented the data-signal of propagation path compensation according to the propagation path estimated value of using described known signal to obtain respectively, described receiving system has: control part, it carries out following control, make about the reliability of signals after the propagation path compensation of the 1st subcarrier, lower than the reliability of signals after the relevant propagation path compensation of the 2nd subcarrier, described the 1st subcarrier has highest frequency in the frequency that is sandwiched in the subcarrier that belongs to described the 1st sub carrier group and the frequency the frequency band between the low-limit frequency, and belong to described the 2nd sub carrier group, described the 2nd subcarrier has the frequency in this frequency band, and belongs to described the 2nd sub carrier group; With error correction portion, it carries out correction process based on the reliability of having carried out described control for the signal after the propagation path compensation of relevant described the 1st subcarrier and described the 2nd subcarrier.

(12) and, also can adopt a kind of receiving system, this receiving system has: propagation path estimation portion, it generates the propagation path estimated value of each subcarrier according to the known received signal in the scheduled communication frequency band; Propagation path compensation section, it uses described propagation path estimated value that the reception data-signal that is mapped to any subcarrier is carried out propagation path compensation; The reliability information generating unit, it obtains the reliability information of the described reception data-signal after the described propagation path compensation; Weighting control portion, it is weighted control, than other subcarrier that lacks, the weighted ratio that makes the reliability information that obtains about these subcarriers is little about the weighting of the reliability information that other subcarrier obtains for the quantity of the described known received signal that is used to ask for described propagation path estimated value; With error correction portion, it uses the reliability information after the described weighting control to carry out the error correction of described data-signal.

(13) wherein, described weighting control portion can be made as the reliability information that obtains at the subcarrier of the end of described communication band or this subcarrier and near subcarrier thereof to the object of described weighting control.

(14) and, described weighting control portion can carry out following control: with the approaching subcarrier of subcarrier of the end of described communication band, make its weight more little.

(15) in addition, described weighting control portion can carry out following control: with the approaching sub carrier group of subcarrier of the end of described communication band, make its weight more little.

(16) and, described weighting control portion can be according to the measurement result of the multidiameter propagation of received signal, control is as the number of subcarriers of the object of described weighting control.

(17) in addition, described weighting control portion can be controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the multidiameter propagation of received signal.

(18) and, described weighting control portion can be controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the reception quality information of received signal.

(19) in addition, under the time dependent situation of the subcarrier that described known received signal is shone upon, described weighting control portion can be according to mapping status separately, and control is as the either party or the both sides of the subcarrier of the object of described weighting control and the weight coefficient that uses in described weighting control.

(20) and, when existing under the situation of a plurality of sub carrier group across the one or more subcarriers that do not send in described communication band, described weighting control portion implements weighting control according to described sub carrier group.

The present invention can improve the error rate characteristic of received signal.

Description of drawings

Fig. 1 shows the block diagram of topology example of the OFDM receiver of the 1st execution mode.

Fig. 2 is the schematic diagram of an example of the LLR weighted of explanation LLR correction unit shown in Figure 1.

Fig. 3 is the schematic diagram of the 1st variation of the LLR weighted of explanation LLR correction unit shown in Figure 1.

Fig. 4 is the schematic diagram of the 2nd variation of the LLR weighted of explanation LLR correction unit shown in Figure 1.

Fig. 5 is the schematic diagram of the 3rd variation of the LLR weighted of explanation LLR correction unit shown in Figure 1.

Fig. 6 is the schematic diagram of the 4th variation of the LLR weighted of explanation LLR correction unit shown in Figure 1.

Fig. 7 shows the block diagram of topology example of the OFDM receiver of the 2nd execution mode.

Fig. 8 is the schematic diagram of an example of the LLR weighted of explanation LLR correction unit shown in Figure 7.

Fig. 9 is the schematic diagram of the 1st variation of the LLR weighted of explanation LLR correction unit shown in Figure 7.

Figure 10 shows the block diagram of topology example of the OFDM receiver of the 3rd execution mode.

Figure 11 is the schematic diagram of an example of the LLR weighted of explanation LLR correction unit shown in Figure 10.

Figure 12 is the schematic diagram of an example of the LLR weighted of explanation the 4th execution mode.

Figure 13 is the schematic diagram of an example of the LLR weighted of explanation the 6th execution mode.

Figure 14 is the schematic diagram of an example of the LLR weighted of explanation the 7th execution mode.

Figure 15 is the schematic diagram of an example of explanation emulation.

Figure 16 shows the curve chart of an example of simulation result.

Figure 17 shows the schematic diagram that in communication band pilot signal and data-signal are mapped to the situation on the subcarrier.

Figure 18 shows the schematic diagram of an example of the received signal corresponding with transmission signal shown in Figure 17.

Figure 19 shows the schematic diagram that carries out the situation that the propagation path of data-signal estimates according to pilot signal shown in Figure 17.

Figure 20 shows the schematic diagram that the pilot signal of a plurality of subcarriers is on average carried out the situation of propagation path estimation in the frequency domain of communication band.

Label declaration

10 OFDM receivers; 11 reception antennas; 12 radio sections; 13 ADC (Analog to DigitalConverter, analog-digital converter); 14 regularly synchronous portions; 15 FFT (Fast FourierTransformer, fast fourier transformer); 16 propagation path estimation portions; 17 propagation path compensation section; 18 LLR operational parts; 19 LLR correction units; 20 error correction portions; 21 postpone the expansion determination part; 22 SNR (Signal to Noise Ratio, signal to noise ratio) determination part.

Embodiment

Below, with reference to the description of drawings embodiments of the present invention.But below Shuo Ming execution mode is an example after all, can not be interpreted as following various distortion that do not illustrate or technology application are foreclosed.That is, the present invention can carry out various distortion (making up each embodiment etc.) and implement in the scope that does not break away from its purport.

(A) brief description

As OFDM (or OFDMA), utilizing in the wireless communication system of multicarrier, having the subcarrier (frequency) of a restriction part and mapping pilot signal and situation about sending.For example, Figure 17 shows in predetermined communication band, comes mapping pilot signal (in order distinguishing with data-signal, to give arrow to pilot signal and explain according to per 2 subcarriers.Also identical later on), and with pilot signal and the multiplexing situation of data-signal (no arrow) that does not comprise pilot signal.What shine upon in the subcarrier of the end of communication band sometimes in this case, is not pilot signal but data-signal.

The signal that changes through multidiameter fading channel, has for example taken place as phase place shown in Figure 180 and amplitude from transmitter in this multiplexed signals, and the machine that is received receives.

In receiver, as previously described,, use pilot signal to carry out propagation path and estimate in order to carry out the propagation path compensation of data-signal.As the one example, Figure 19 shows the situation of carrying out the propagation path estimation of data-signal (no arrow) based on pilot signal shown in Figure 17 (arrow).

For example, can be by the propagation path estimated value that obtains from two pilot signals that are mapped to adjacent sub-carrier be carried out linear interpolation, obtain the propagation path estimated value of the subcarrier that data-signal shines upon.

Here, as shown in figure 19, when in the subcarrier that is mapped to the communication band end be not pilot signal the time, for example can obtain the propagation path estimated value of this subcarrier by extrapolation.

But extrapolation is compared with interpolation, because the pilot signal quantity of using is few, so the precision of propagation path estimated value worsens easily.Therefore, when data-signal is mapped to the subcarrier of end of communication band, consequently in this propagation path compensation, used other propagation path of ratio of precision to estimate the propagation path estimated value of value difference.As a result, the precision of the LLR of the data-signal after the propagation path compensation is variation also, and error rate increases when causing error correction, can not obtain enough receptivities sometimes.

In addition, even pilot signal is being mapped under the situation of the whole subcarriers in the communication band, the subcarrier of the end of communication band is compared with other subcarrier, can not obtain enough receptivities sometimes.

For example, as shown in figure 20, consider that pilot signal is mapped to the received signal of whole subcarriers of communication band.When the propagation path that carries out certain subcarrier is estimated, carry out propagation path and estimate by the pilot signal of subcarrier is on every side averaged sometimes.

Its objective is that under the less situation of multidiameter propagation, the tendency that the correlation of the propagation path estimated value of subcarrier uprises around utilizing averages a plurality of pilot signals, obtains high-precision propagation path estimated value thus.

For example, consider to estimate that as propagation path the subcarrier of object is that each 1 subcarrier of both sides is got as average object (that is, obtaining the average of 3 subcarriers of total) in the center.In this case,, can carry out the average of 3 subcarriers, only carry out the average of 2 subcarriers for the two ends of communication band for the center of communication band.

In this case, the precision of the propagation path estimated value relevant with the subcarrier at communication band two ends is easily than the low precision of the propagation path estimated value of other subcarrier.Therefore, in this case, the error rate of data-signal also increases, and can not obtain enough receptivities sometimes.

In other words, about the subcarrier that the pilot signal quantity that is used to ask for the propagation path estimated value is lacked than other subcarrier, other subcarrier of the ratio of precision of the LLR that it obtains is poor.

Therefore, in the present embodiment, about as the communication band end or as communication band end and near subcarrier thereof, be used for the subcarrier that propagation path estimated pilot signal quantity is less than predetermined quantity, the reliability information (LLR) of the reception data-signal that is mapped to this subcarrier is carried out than the weighting control a little less than other reliability information.

Here, the sub carrier group corresponding with a plurality of subcarriers that send the pilot signal be used to obtain the propagation path estimated value respectively is made as the 1st sub carrier group, the sub carrier group corresponding with a plurality of subcarriers that send the data-signal implemented propagation path compensation (this propagation path compensation be based on the propagation path estimated value of using the described pilot signal to obtain carry out) respectively is made as the 2nd sub carrier group, the object that carries out described weighting control this moment will be about the reliability of signals after the propagation path compensation of following subcarrier, described subcarrier has highest frequency in being sandwiched in the subcarrier that belongs to described the 1st sub carrier group and the frequency the frequency band between the low-limit frequency, and belongs to described the 2nd sub carrier group.

Promptly, carry out following control, make about the reliability of signals after the propagation path compensation of following the 1st subcarrier, lower than the reliability of signals after the relevant propagation path compensation of following the 2nd subcarrier, described the 1st subcarrier has highest frequency in being sandwiched in the subcarrier that belongs to described the 1st sub carrier group and the frequency the frequency band between the low-limit frequency, and belong to described the 2nd sub carrier group, described the 2nd subcarrier has the frequency in the described frequency band, and belongs to described the 2nd sub carrier group.

Thus, can suppress the LLR that precision is lower and be used for error correction, improve the error rate characteristic of the data-signal after the error correction.In addition, " communication band end " comprises the situation of expression subcarrier of minimum or highest frequency in the communication band below, also comprises the situation that comprises near the one or more subcarriers this subcarrier.

(B) the 1st execution mode

Fig. 1 shows the block diagram of topology example of the OFDM receiver of the 1st execution mode.

This OFDM receiver shown in Figure 1 (following also abbreviate as " receiver ") 10, for example have reception antenna 11, radio section 12, ADC (Analog to Digital Converter, analog-digital converter) 13, regularly portion 14, FFT (Fast Fourier Transformer, fast Fourier transformer) 15, propagation path estimation portion 16, propagation path compensation section 17, LLR operational part 18, LLR correction unit 19 and error correction portion 20 synchronously.In addition, this OFDM receiver 10 can be applied to the receiving system of wireless base station, also can be applied to the receiving system of wireless terminal (travelling carriage).

Wherein, reception antenna 11 receives the signal (OFDM symbol) that sends by multicarrier from OFDM transmitter (omitting diagram).

Radio section 12 is for the signal that is received by this reception antenna 11, carries out the reception of frequency band limits that low noise amplifies, carries out to the frequency inverted (down-conversion) of base band frequency, by roll-off filter etc. etc. and handles.

ADC 13 is converted to digital signal with the received signal that radio section 12 has carried out after described reception is handled.Resulting digital signal is imported into regularly portion 14 and FFT 15 synchronously.

Regularly synchronously the significant character composition detects in portion 14 from the received signal of the digital signal that obtains by ADC 13, it is detected regularly regularly export to FFT 15 as FFT.

FFT 15 handles carry out FFT from the digital signal (time-domain signal) of ADC 13 in the regularly described FFT timing of portion's 14 outputs synchronously, is converted to frequency-region signal thus.

The frequency-region signal of propagation path estimation portion 16 after described FFT handles, the sub-carrier frequencies composition that detection is shone upon as the pilot signal of known received signal, according to this pilot signal estimate and the OFDM transmitter between propagation path, obtain the propagation path estimated value of each subcarrier.In addition, about the propagation path estimated value of the subcarrier that do not have mapping pilot signal, can obtain by interpolation or extrapolation.And, also can as narrating, the front obtain the propagation path estimated value by a plurality of pilot signals are averaged.

Propagation path compensation section 17 uses the propagation path estimated value of each subcarrier that obtains by propagation path estimation portion 16 to carry out propagation path compensation at the data-signal composition in arbitrary subcarrier of the subcarrier that is mapped to the frequency-region signal after described FFT handles.

LLR operational part (reliability information generating unit) 18 has been at having carried out the data-signal after the propagation path compensation by propagation path compensation section 17, obtains the LLR (it is a kind of of the reliability information used when carrying out error correction (soft-decision decoding) by error correction portion 20) of every bit.

LLR correction unit (weighting control portion) 19 LLR for the described every bit that obtains by LLR operational part 18 carry out the weighting control corresponding with subcarrier and proofread and correct.For example, when existing as the communication band end, carrying out extrapolation when waiting subcarrier that employed pilot signal number when obtaining the propagation path estimated value lacks than the pilot signal number of other subcarrier use, LLR correction unit 19 makes the weight of its LLR lower than the LLR that obtains about other subcarrier for this subcarrier.

Error correction portion 20 uses the LLR that has carried out the every bit after the described correction (weighting) by LLR correction unit 19, carries out the error correction of received signal.Here, in LLR correction unit 19, to using the LLR that has carried out the data-signal of propagation path compensation based on the propagation path compensation value of extrapolation when the ratio of precision interpolation during extrapolation (usually low) to implement weighting, make its weight be lower than the data-signal of propagation path compensation has been carried out in use based on the propagation path compensation value of interpolation the weight of LLR, so can suppress the deterioration of the error rate characteristic of integral body, obtain the receptivity of expection.

Below, about the action of the OFDM receiver 10 of this example of formation as mentioned above, narrate propagation path compensation section 17, LLR operational part 18 and LLR correction unit 19 emphatically.

The number of subcarriers of communication band is expressed as N _cIndividual, with subcarrier #k (wherein, 0≤k≤N _c-1) the propagation path estimated value table in is shown

The reception data (data after FFT handles) of receiver 10 sub-carriers #k are expressed as r (k).

In propagation path compensation section 17, the reception data r (k) at each subcarrier #k compensates the distortion that is subjected to by propagation path shown in following formula (1).

Formula (1)

$\tilde{s}\left(k\right)={\tilde{h}}^{*}\left(k\right)\×r\left(k\right)\·\·\·\left(1\right)$

Then, in LLR operational part 18, to having carried out the signal of propagation path compensation

Obtain the LLR of every bit.For example,

Represent by the N bit, this n table of bits is being shown b _n(k) { 1, during+1}, its LLR is found the solution it in LLR operational part 18 by following formula (2) expression ∈.

Formula (2)

${\mathrm{\λ}}_1\left(b_n\left(k\right)\right)=\ln \frac{\mathrm{Pr}\left(\tilde{s}\left(k\right)\right|b_n\left(k\right)=+1)}{\mathrm{Pr}\left(\tilde{s}\left(k\right)\right|b_n\left(k\right)=-1)}\·\·\·\left(2\right)$

In addition, the P that represents as this formula (2) _r(X|Y) be meant the probability of the tape spare X among the Y.

The LLR of every bit that LLR correction unit 19 will obtain by above-mentioned formula (2) multiply by the weight coefficient corresponding with subcarrier #k (below be also referred to as the LLR weight coefficient).

For example, shown in Fig. 2 (1), in communication band, come mapping pilot signal according to per 3 subcarriers, in 3 subcarriers at communication band two ends, be mapped with data-signal, in this case, for example obtain the propagation path estimated value of data-signal of 3 subcarriers at relevant these two ends by extrapolation.

Therefore, in LLR correction unit 19, carry out processing by following formula (3) expression.

Formula (3)

${\mathrm{\&lambda;}}_2\left(b_n\left(k\right)\right)=\left\{\begin{array}{cc}{\mathrm{\&alpha;}}_1\&times;{\mathrm{\&lambda;}}_1\left(b_n\left(k\right)\right)& (0\&le;k\&le;k_1)\\ {\mathrm{\&alpha;}}_2\&times;{\mathrm{\&lambda;}}_1\left(b_n\left(k\right)\right)& ({\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HPA00001168068100031.png,HPA00001168068100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_1<k<K_2)\\ {\mathrm{\&alpha;}}_3\&times;{\mathrm{\&lambda;}}_1\left(b_n\left(k\right)\right)& ({\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="HPA00001168068100061.png,HPA00001168068100081.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\&le;k\&le;N_e-1)\end{array}\right.\&CenterDot;\&CenterDot;\&CenterDot;\left(3\right)$

Above-mentioned formula (3) expression, for example shown in Fig. 2 (2), in frequency domain by subcarrier #k=K ₁And K ₂(＞K ₁) communication band is cut apart and in 3 intervals obtaining, to the LLR (λ that obtains according to above-mentioned formula (2) ₁(b _n(k))) multiply by weight coefficient α respectively ₁, α ₂, α ₃

That is, in the example shown in (2) of Fig. 2,3 subcarrier #k=0,1,2 (K that the lower frequency side frequency domain that carries out extrapolation (below be also referred to as the extrapolation interval) is comprised ₁) LLR, multiply by weight coefficient α respectively ₁, 3 subcarrier #k=N that the extrapolation interval of high frequency side is comprised _c-3 (K ₂), N _c-2, N _c-1 LLR multiply by weight coefficient α respectively ₃, the LLR of the subcarrier #k that the frequency domain in remaining non-extrapolation interval (for example, obtaining the frequency domain (the following interpolation interval that also is referred to as) based on the propagation path estimated value of interpolation) is comprised multiply by weight coefficient α ₂

This is equivalent to carry out following control, promptly, make reliability about the signal (being the signal in extrapolation interval) after the propagation path compensation of the 1st subcarrier, lower than the reliability of signals after the relevant propagation path compensation of the 2nd subcarrier, described the 1st subcarrier has the frequency in (extrapolation interval) highest frequency in being sandwiched in the sub-carrier frequencies that belongs to the 1st sub carrier group (its respectively pilot signal transmitted) and the frequency band between the low-limit frequency, and belong to the 2nd sub carrier group (it sends the data-signal of having implemented propagation path compensation according to pilot signal respectively), described the 2nd subcarrier has the frequency of (in the frequency band except that the extrapolation interval) in the described frequency band, and belongs to described the 2nd sub carrier group.

Wherein, about the weight coefficient α in extrapolation interval ₁, α ₃(wherein, 0≤α ₁, 0≤α ₃) with the weight coefficient α in interpolation interval ₂(wherein, 0＜α ₂) between relation, for example be made as α ₁＜α ₂, α ₃＜α ₂That is, multiply by weight coefficient α than interpolation interval at the LLR in extrapolation interval ₂Little weight coefficient α ₁, α ₂As an example, preestablish numerical value α ₁=0.4, α ₂=1, α ₃=0.3.In addition, α ₂Higher limit can not be 1 also.In this example, be redefined for numerical value α ₁=0.4, α ₂=1, α ₃=0.3, but also can be set at for example 2 times of these numerical value, α ₁=0.8, α ₂=2, α ₃=0.6.

Like this, import by 19 couples of LLR λ that obtain by LLR operational part 18 of LLR correction unit to error correction portion 20 ₁(b _n(k)) be weighted λ after the processing ₂(b _n(k)), can improve the error rate characteristic thus.

In addition, in above-mentioned example, be made as α ₃＜α ₁, but also can be made as α ₃=α ₁, can also be made as α ₃＞α ₁

(b1) the 1st variation

In (2) of Fig. 2, only the extrapolation interval be multiply by than the interval little weight coefficient of interpolation, but as the front according to Figure 20 narration like that under situation about on the frequency direction pilot signal of a plurality of subcarriers being averaged, can include the LLR of the subcarrier #k in extrapolation interval, pass.

Therefore, also exist, also the part (comparing the interval interval near the communication band central side of extrapolation) in interpolation interval is carried out the situation of the weighted identical with the extrapolation interval preferably not only to the extrapolation interval.For example, as shown in Figure 3, also can multiply by and compare α the interval that comprises near a part of interpolation interval the extrapolation interval ₂Little weight coefficient α ₁, α ₂

In addition, in this example, the situation of carrying out extrapolation, interpolation when obtaining the propagation path estimated value has been described, but as the front is narrated according to Figure 20, even under the situation that the propagation path estimated value to a plurality of subcarriers averages, can use above-mentioned weighted of being undertaken by LLR correction unit 19 too, this point is also identical in the explanation of back.

(b2) the 2nd variation

In addition, above-mentioned example is the situation of carrying out extrapolation at the communication band two ends, but also has situation for example shown in Figure 4, that is, utilize mapping (configuration) method of pilot signal only to carry out the situation of extrapolation at the edge of communication band one side.In this case, shown in following formula (4), can only multiply by the weight coefficient α littler than other subcarrier to carrying out subcarrier #k extrapolation, communication band one side ₁(＜α ₂).

Formula (4)

${\mathrm{\&lambda;}}_2\left(b_n\left(k\right)\right)=\left\{\begin{array}{cc}{\mathrm{\&alpha;}}_1\&times;{\mathrm{\&lambda;}}_1\left(b_n\left(k\right)\right)& (0\&le;k\&le;K_1)\\ {\mathrm{\&alpha;}}_2\&times;{\mathrm{\&lambda;}}_1\left(b_n\left(k\right)\right)& ({\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HPA00001168068100031.png,HPA00001168068100061.png"\; state="\{\{state\}\}">K</figure-callout>}}_1<k\&le;N_e-1)\end{array}\right.\&CenterDot;\&CenterDot;\&CenterDot;\left(4\right)$

(b3) the 3rd variation

In above-mentioned example, with the LLR weight coefficient α in extrapolation interval ₁, α ₃Be made as in this interval fixing (identical), but also can multiply by different LLR weight coefficient α at each or a plurality of subcarrier about the extrapolation interval.

For example, as shown in Figure 5, consider that the extrapolation interval is in the long situation of frequency direction.As previously mentioned, the precision of the propagation path estimated value of obtaining by extrapolation has more the trend near the easy more deterioration in communication band end, so LLR correction unit 19 for example is divided into the extrapolation interval a plurality of block of sub-carriers (group), in part or all piece LLR is carried out different weightings.

In the example of Fig. 5, respectively 3 subcarriers are carried out extrapolation at the communication band two ends, left end (lower frequency side) is adopted according to each subcarrier 3 different LLR weight coefficient α ₁, α ₂, α ₃On the other hand,, be divided into 1 subcarrier and 2 subcarriers, adopt different LLR weight coefficient α respectively right-hand member (high frequency side) ₅, α ₆Wherein, near the subcarrier of the end of communication band, the more little (α of its LLR weight coefficient ₁＜α ₂＜α ₃＜α ₄, α ₄＞α ₅＞α ₆).

(b4) the 4th variation

In addition, in the extrapolation interval, can not change the LLR weight coefficient yet, but a plurality of subcarriers of a part are used identical LLR weight coefficient at each subcarrier.For example, as shown in Figure 6, in LLR correction unit 19,, be made as L in the left end side of communication band for the siding-to-siding block length that multiply by the LLR weight coefficient (number of subcarriers) _l, be made as L in the right-hand member side _rIn this example, suppose according to these siding-to-siding block lengths L _l, L _rCarry out extrapolation.

And, with L _lBe divided into M _lIndividual (M _lBe the integer more than 2), with M _lIndividual each interval number of subcarriers is expressed as N respectively _l(1)～N _l(M _l) (all being the integer more than 1), equally with L _rBe divided into M _rIndividual (M _rBe the integer more than 2), with M _rIndividual each interval number of subcarriers is expressed as N respectively _r(1)～N _r(M _r) (all being the integer more than 1).

Wherein, M _l, N _l(1)～N _l(M _l), M _r, N _r(1)～N _r(M _r) value can be predefined value.For example, as shown in Figure 6, can preestablish M _l=3, N _l(1)=2, N _l(2)=2, N _l(3)=1, M _r=2, N _r(1)=2, N _r(2)=2 the value of grade.

In this example, at N _l(1) the LLR weight coefficient of using in the interval is α ₁, at N _l(2) the LLR weight coefficient of using in the interval is α ₂, at N _l(3) the LLR weight coefficient of using in the interval is α ₃, at N _r(1) the LLR weight coefficient of using in the interval is α ₅, at N _r(2) the LLR weight coefficient of using in the interval is α ₆, and with respect to the LLR weight coefficient α of band center side ₄, be made as (0≤) α ₁＜α ₂＜α ₃＜α ₄, (1 〉=) α ₄＞α ₅＞α ₆

That is to say that in this example, LLR correction unit 19 is for the subcarrier the closer to the end of communication band, it is more little value that the LLR weight coefficient of its application is set (control).Thus, even under the situation of the easy more deterioration of propagation path estimated value that obtains in subcarrier place, also can improve the error rate characteristic effectively the closer to the end of communication band.

(C) the 2nd execution mode

Under the big situation of multidiameter propagation, because the change of propagation path value between the subcarrier is bigger, so worsen easily based on the precision of the propagation path estimated value of extrapolation.Consider this point, LLR correction unit 19 also can change described M adaptively according to postponing propagation _l, N _l(1)～N _l(M ₁), M _r, N _r(1)～N _r(M _r) value (that is, the extrapolation interval cut apart between quantity, cut section in the number of subcarriers that comprises).

Therefore, in the OFDM of present embodiment receiver 10, for example, as shown in Figure 7, be provided with and postpone expansion determination part 21, this delay expansion determination part 21 is used for measuring the delay propagation according to the propagation path estimated value that is obtained by propagation path estimation portion 16, and LLR correction unit 19 postpones the measurement result of expansion determination part 21 according to this, the LLR weight coefficient that control adaptively will be used.

For example, postponing under the propagation situation bigger, because the change of the propagation path value between the subcarrier is bigger, so the closer to the band edge in extrapolation interval, the precision of propagation path estimated value is poor more than threshold value.Therefore, in postponing the bigger extrapolation interval of expansion, be preferably the quantity of cutting apart that increases this interval, to using different LLR weight coefficients between cut section.

On the other hand, postponing under the less situation of propagation, so poor when big based on the precision of the propagation path estimated value of extrapolation unlike postponing expansion, so compare the bigger situation of propagation that postpones, that can reduce the extrapolation interval cuts apart quantity (perhaps not cutting apart), and minimizing will weaken between the target area of weighting of LLR.

For example, about by postponing delay propagation that expansion determination part 21 measures than little situation of certain threshold value and the situation bigger, in LLR correction unit 19, in advance with two kinds of M than certain threshold value _l, N _l(1)～N _l(M ₁), M _r, N _r(1)～N _r(M _r) value be kept in memory etc., LLR correction unit 19 is switched these numerical value adaptively according to the comparison of described delay propagation and described threshold value.But the value that is kept in the described memory is not limited to above-mentioned two kinds.

Fig. 8 represents the one example.In addition, Fig. 8 (1) is illustrated in the communication band, comes mapping pilot signal according to per 5 subcarriers, respectively at the siding-to-siding block length L at communication band two ends _l, L _rCarry out the situation of extrapolation.And Fig. 8 (2) expression is by the situation of the weighting that postpones delay propagation that expansion determination part 21 the measures LLR when bigger than threshold value, and (3) expression of Fig. 8 is by postponing the situation that delay propagation that expansion determination part 21 measures is the weighting of the LLR of threshold value when following.

That is,, for example, establish M when postponing propagation than threshold value hour _l=1, M _r=1, reduce the interval quantity of using the LLR weight coefficient.On the other hand, postponing to expand to threshold value when above, according to M _l=3, M _r=2 mode is cut apart the extrapolation interval, uses different LLR weight coefficients between each cut section.

In addition, this example will postpone propagation as benchmark, but also can be alternatively or additionally, and the variation of the propagation path estimated value between the adjacent sub-carrier as benchmark, is carried out identical processing.

(c1) the 1st variation

The precision of the propagation path estimated value when as previously described, carrying out extrapolation has the trend that the big more precision of delay propagation worsens more.In above-mentioned the 2nd execution mode, show according to postponing the example that propagation is controlled the application interval of LLR weight coefficient adaptively.In this variation, illustrate according to postponing the example that delay propagation that expansion determination part 21 determined is controlled the LLR weight coefficient that LLR correction unit 19 will use adaptively.

Fig. 9 represents the one example.In addition, Fig. 9 (1) is illustrated in the communication band, comes mapping pilot signal according to per 3 subcarriers, carries out the situation of extrapolation in the interval at communication band two ends respectively.And Fig. 9 (2) expression is by the situation of the weighting that postpones delay propagation that expansion determination part 21 the measures LLR when bigger than threshold value, and (3) expression of Fig. 9 is by postponing the situation that delay propagation that expansion determination part 21 measures is the weighting of the LLR of threshold value when following.

That is, set certain threshold value, if by postponing the delay propagation σ that expansion determination part 21 is measured about postponing propagation _s ²Less than this threshold value, then LLR correction unit 19 is made as (α shown in Fig. 9 (2) ₁, α ₂, α ₃)=(A ₁ ⁽¹⁾, A ₂ ⁽¹⁾, A ₃ ⁽¹⁾), if σ _s ²More than threshold value, then LLR correction unit 19 is made as (α shown in Fig. 9 (3) ₁, α ₂, α ₃)=(A ₁ ⁽²⁾, A ₂ ⁽²⁾, A ₃ ⁽²⁾).Wherein, (0≤) A ₃ ⁽¹⁾＜A ₁ ⁽¹⁾＜A ₂ ⁽¹⁾, (0≤) A ₃ ⁽²⁾＜A ₁ ⁽²⁾＜A ₂ ⁽²⁾And, A ₁ ⁽¹⁾, A ₂ ⁽¹⁾, A ₃ ⁽¹⁾, A ₁ ⁽²⁾, A ₂ ⁽²⁾, A ₃ ⁽²⁾It can be predefined value.

In other words, LLR correction unit 19 control LLR weight coefficients make postponing propagation σ _s ²Than threshold value hour, the LLR weight coefficient of communication band both end sides and the LLR weight coefficient of communication band central side bigger postponing propagation σ _s ²Be described threshold value when above, described ratio is less.This control can be by for example following formula (5) expression.

Formula (5)

$\frac{A_1^{\left(1\right)}}{A_2^{\left(1\right)}}>\frac{A_1^{\left(2\right)}}{A_2^{\left(2\right)}},\frac{A_3^{\left(1\right)}}{A_2^{\left(1\right)}}>\frac{A_3^{\left(2\right)}}{A_2^{\left(2\right)}}\&CenterDot;\&CenterDot;\&CenterDot;\left(5\right)$

In addition, LLR correction unit 19 also can be defined as the LLR weight coefficient to postpone propagation σ _s ²Function, for example be made as (α ₁, α ₂, α ₃)=(f ₁(σ _s ²), f ₂(σ _s ²), f ₃(σ _s ²)).

And, also can substitute the delay propagation or additionally the variation of the propagation path estimated value between the adjacent sub-carrier be carried out above-mentioned weighted as benchmark.

(D) the 3rd execution mode

In OFDM receiver 10, under the lower situation of the signal to noise ratio (SNR:Signal to NoiseRatio) of received signal, to compare with the SNR condition with higher, the precision of propagation path estimated value has the trend of variation in the whole zone of communication band.In this case, also can not carry out the LLR weighting.

Therefore, in the OFDM of present embodiment receiver 10, for example as shown in figure 10, SNR determination part 22 preferably is set, this SNR determination part 22 is used for measuring reception SNR according to the propagation path estimated value that is obtained by propagation path estimation portion 16, SNR according to being measured by this SNR determination part 22 controls the LLR weight coefficient that will use adaptively by LLR correction unit 19.

Figure 11 represents the one example.In addition, Figure 11 (1) is illustrated in the communication band, according to per 3 subcarrier mapping pilot signals, carries out the situation of extrapolation respectively in the interval at communication band two ends.And, the situation of the weighting of the LLR of the SNR (γ) that Figure 11 (2) expression is measured by SNR determination part 22 during less than threshold value, the SNR (γ) that (3) expression of Figure 11 is measured by SNR determination part 22 is the situation of the weighting of the LLR of described threshold value when above.

That is, set certain threshold value about receiving SNR, if the SNR (γ) that measures by SNR determination part 22 less than this threshold value, then LLR correction unit 19 is made as (α with the LLR weight coefficient of application as Figure 11 (2) shown in ₁, α ₂, α ₃)=(Γ ₁ ⁽¹⁾, Γ ₂ ⁽¹⁾, Γ ₃ ⁽¹⁾), if SNR (γ) is more than the described threshold value, then LLR correction unit 19 is made as (α shown in Figure 11 (3) ₁, α ₂, α ₃)=(Γ ₁ ⁽²⁾, Γ ₂ ⁽²⁾, Γ ₃ ⁽²⁾).In addition, in the example depicted in fig. 11, be made as Γ ₂ ⁽¹⁾＞Γ ₁ ⁽¹⁾＞Γ ₃ ⁽¹⁾(〉=0), Γ ₂ ⁽²⁾＞Γ ₁ ⁽²⁾＞Γ ₃ ⁽²⁾(〉=0).And, Γ ₁ ⁽¹⁾, Γ ₂ ⁽¹⁾, Γ ₃ ⁽¹⁾, Γ ₁ ⁽²⁾, Γ ₂ ⁽²⁾, Γ ₃ ⁽²⁾It can be predefined value.

In other words, the LLR weight coefficient that LLR correction unit 19 control will be used makes when receiving SNR less than threshold value, the LLR weight coefficient of communication band both end sides and the LLR weight coefficient of communication band central side bigger, receiving SNR is threshold value when above, and described ratio is less.This control can utilize for example following formula (6) expression.

Formula (6)

$\frac{{\mathrm{\&Gamma;}}_1^{\left(1\right)}}{{\mathrm{\&Gamma;}}_2^{\left(1\right)}}>\frac{{\mathrm{\&Gamma;}}_1^{\left(2\right)}}{{\mathrm{\&Gamma;}}_2^{\left(2\right)}},\frac{{\mathrm{\&Gamma;}}_3^{\left(1\right)}}{{\mathrm{\&Gamma;}}_2^{\left(1\right)}}>\frac{{\mathrm{\&Gamma;}}_3^{\left(2\right)}}{{\mathrm{\&Gamma;}}_2^{\left(2\right)}}\&CenterDot;\&CenterDot;\&CenterDot;\left(6\right)$

In addition, the LLR weight coefficient that LLR correction unit 19 also can be used is defined as the function of SNR (γ), for example is made as (α ₁, α ₂, α ₃)=(f ₁(γ), f ₂(γ), f ₃(γ)).

(E) the 4th execution mode

LLR correction unit 19 also can be controlled the LLR weight coefficient that will use according to the measurement result of described delay propagation and reception SNR.The OFDM receiver 10 of this moment adds being provided with delay expansion determination part 21 and SNR determination part 22 shown in Figure 10 shown in Figure 7 with respect to structure shown in Figure 1.

And in LLR correction unit 19, the size that for example postpones the propagation measurement result is respectively judged the size judgement (threshold determination) of (threshold determination), SNR measurement result, about adding up to 4 kinds ((to postpone expansion, SNR)=(little, little), (little, greatly), (big, little), (big, result of determination greatly)) pre-determines 4 kinds of LLR weight coefficient (α ₁, α ₂, α ₃) value, be kept in memory etc., LLR be multiply by the LLR weight coefficient corresponding with any result of determination.

Figure 12 represents the one example.Wherein, Figure 12 (1) is illustrated in the communication band, according to per 3 subcarrier mapping pilot signals, carries out the situation of extrapolation respectively in the interval at communication band two ends.And, the described result of determination of Figure 12 (2-1) expression be (postpone to expand, SNR)=

The situation of the LLR weighting when (little, little), the described result of determination of (2-2) expression of Figure 12 are (to postpone expansion, the situation of the LLR weighting in the time of SNR)=(little, big).Equally, the described result of determination of Figure 12 (2-3) expression is that (postpone expansion, the situation of the LLR weighting in the time of SNR)=(big, little), the described result of determination of (2-4) expression of Figure 12 are (to postpone expansion, the situation of the LLR weighting in the time of SNR)=(big, big).

And, in the example of this Figure 12, at aforementioned 4 kinds of result of determination, as the LLR weight coefficient (α of the definition application of getting off ₁, α ₂, α ₃).

(2-1) (postpone expansion, SNR)=(little, little) → (α ₁, α ₂, α ₃)=(A ₁ ⁽¹⁾, A ₂ ⁽¹⁾, A ₃ ⁽¹⁾)

(2-2) (postpone expansion, SNR)=(little, big) → (α ₁, α ₂, α ₃)=(A ₁ ⁽²⁾, A ₂ ⁽²⁾, A ₃ ⁽²⁾)

(2-3) (postpone expansion, SNR)=(big, little) → (α ₁, α ₂, α ₃)=(A ₁ ⁽³⁾, A ₂ ⁽³⁾, A ₃ ⁽³⁾)

(2-4) (postpone expansion, SNR)=(big, big) → (α ₁, α ₂, α ₃)=(A ₁ ⁽⁴⁾, A ₂ ⁽⁴⁾, A ₃ ⁽⁴⁾)

Wherein, A ₁ ⁽ⁱ⁾, A ₂ ⁽ⁱ⁾, A ₃ ⁽ⁱ⁾The magnitude relationship of (arbitrary value among the i=1,2,3,4) is A ₂ ⁽ⁱ⁾＞A ₁ ⁽ⁱ⁾＞A ₃ ⁽ⁱ⁾(〉=0).

In addition, in this example, under the SNR that the is measured situation littler, the LLR weight coefficient in the extrapolation interval of communication band end side is set the value more smaller than the LLR weight coefficient of communication band central side than threshold value.And, all under the big situation, the LLR weight coefficient in the extrapolation interval of communication band end side is made as the weight coefficient littler than the LLR weight coefficient of communication band central side than threshold value at the delay propagation of being measured and SNR.

Like this, according to this example, can based on the delay propagation of received signal and SNR both, realize extremely careful more flexibly LLR weight coefficient control, the suitable LLR weighting control corresponding can be realized, the improvement of error rate characteristic can be more effectively realized with wireless communications environment.

(F) the 5th execution mode

Also can be made as arbitrary example of fixing/variable example to interval, make up with the arbitrary example that aforementioned LLR weight coefficient is made as fixing/variable example and implement application of aforementioned LLR weight coefficient.

(G) the 6th execution mode

In ofdm communication system, exist the configuration (mapping) of the pilot signal be mapped to subcarrier to change in time or the configuration of pilot signal according to each sub-district and different situations.

Figure 13 represents an example of the time dependent situation of configuration of pilot signal.Following situation has been shown in this Figure 13, (1) at T1 sometime, pilot signal is mapped to the two ends of communication band, (2) at T2 sometime, pilot signal is not mapped to the two ends of communication band, (3) at T3 sometime, pilot signal is not mapped to the two ends of communication band, and the configuration space of pilot signal is also different with moment T1, T2.

Like this, changing according to the time under the situation that has multiple pilot signal configuration, preferred LLR correction unit 19 is determined (control) LLR weight coefficient and the either party or the both sides that will use the siding-to-siding block length of LLR weight coefficient in all cases according to noted earlier.

For example, in the example of Figure 13, at the moment of (1) T1, since do not carry out extrapolation, so the LLR weight coefficient is a fixed value in whole subcarriers of communication band, moment T2 and T3 in (2) and (3), for each extrapolation interval, use different LLR weight coefficients at each subcarrier.

In the example of Figure 13 and since when constantly the pilot signal quantity in the communication band is than T2 constantly during T3 lack and extrapolation interval long, so compare T2 constantly, at moment T3 to the more subcarrier application LLR weight coefficient littler than center frequency-band side.

In addition, identical with above-mentioned situation under the configuration of the pilot signal situation different according to each sub-district, determine (control) LLR weight coefficient and the siding-to-siding block length either party or the both sides that will use the LLR weight coefficient according to each sub-district.

Like this,, under the situation that has the configuration of different pilot signal, also suitable LLR weighting control can be implemented respectively, and the receptivity expected can be easily guaranteed according to this example.

(H) the 7th execution mode

For example, as shown in figure 14, in communication band, there are one or more subcarriers that can not send from the OFDM transmitter, and exist under the situation of a plurality of sub carrier group (piece) across this subcarrier, about the edge of each block of sub-carriers, the precision of its propagation path estimated value is poor than non-marginal portion easily.

Therefore, LLR correction unit 19 can be a unit with this block of sub-carriers, uses independently and determines LLR weight coefficient that (control) is narrated previously and siding-to-siding block length either party or the both sides that use the LLR weight coefficient.

(I) simulation result

The result's of the error rate characteristic of proofreading and correct based on above-mentioned LLR a example is measured in Figure 16 emulation of representing to use a computer.This measurement result is to establish 2 * 2 MIMO (Multi-Input Multi-Output, multiple-input and multiple-output), 64QAM, encoding rate (Coding Rate)=3/4, the measurement result when transmission environment is 6 footpath typical city section models (6-ray Typical Urban Model).

And, in this emulation, for example be made as pilot frequency configuration shown in Figure 15, serve as to insert pilot signal at interval with 6 subcarriers.And, only insert pilot signal in 1OFDM symbol in 1 time slot (=7OFDM symbol) and the 5th OFDM symbol.In addition, the OFDM symbol is meant a part of duplicating significant character circularly and it is attached to the signal unit in this significant character as protection interval (GI) (being also referred to as Cyclic Prefix (CP)).

Suppose as follows about the interval of carrying out extrapolation, for the 1OFDM symbol, at communication band left side (lower frequency side) to 1 subcarrier, 5 subcarriers are carried out extrapolation at communication band right side (high frequency side), for the 5OFDM symbol, in communication band left side to 4 subcarriers, 2 subcarriers are carried out extrapolation on the communication band right side.

Therefore, in this emulation, carried out the above-mentioned LLR weighting of being undertaken by LLR correction unit 19 at 4 subcarriers in frequency band left side, 5 subcarriers in frequency band left side.Establish at the band center side that the LLR weight coefficient is 1, both end sides is 0.3.

In this case, about the OFDM symbol (the 2nd～4,6,7 OFDM symbols in the time slot) that does not insert pilot signal, be that the propagation path estimated accuracy of communication band end side is relatively poor equally, so adopted same LLR weight coefficient.

Learn according to Figure 16, proofread and correct, compared in the past (with reference to label 100) by the LLR that uses this example, can be with frame error rate (FER:Frame Error Rate)=needed SNR improved roughly 6dB (with reference to label 200) in 0.1 o'clock.

Claims (20)

1. the receiving handling method of a receiving system corresponding with multicarrier, this receiving system receives the 1st sub carrier group and the 2nd sub carrier group, the 1st sub carrier group is corresponding to a plurality of subcarriers that send the known signal be used to obtain the propagation path estimated value respectively, the 2nd sub carrier group is corresponding to sending a plurality of subcarriers of having implemented the data-signal of propagation path compensation according to the propagation path estimated value of using described known signal to obtain respectively, described receiving handling method is characterised in that, may further comprise the steps:

Control, reliability of signals after making reliability of signals after the relevant propagation path compensation of the 1st subcarrier than the relevant propagation path compensation of the 2nd subcarrier is low, described the 1st subcarrier has highest frequency in the frequency that is sandwiched in the subcarrier that belongs to described the 1st sub carrier group and the frequency the frequency band between the low-limit frequency and belongs to described the 2nd sub carrier group, described the 2nd subcarrier has the frequency in this frequency band and belongs to described the 2nd sub carrier group

Based on the reliability of having carried out described control, carry out correction process for the signal after the propagation path compensation of relevant described the 1st subcarrier and described the 2nd subcarrier.

2. the receiving handling method in the multi-carrier communication is characterized in that, said method comprising the steps of:

According to the known received signal in the scheduled communication frequency band, generate the propagation path estimated value of each subcarrier,

Use described propagation path estimated value, the reception data-signal that is mapped to any subcarrier carried out propagation path compensation,

Obtain the reliability information of the described reception data-signal after the described propagation path compensation,

Be weighted control, the subcarrier that lacks than other subcarrier for the quantity of the described known received signal that is used to ask for described propagation path estimated value, make the weight of the reliability information that obtains about these subcarriers littler than the weight of the reliability information that obtains about other subcarrier

Use the reliability information after the described weighting control to carry out the error correction of described reception data-signal.

3. receiving handling method according to claim 2 is characterized in that, described weighting control to as if the reliability information that obtains at the subcarrier of the end of described communication band or this subcarrier and near subcarrier thereof.

4. receiving handling method according to claim 3 is characterized in that, described weighting control is following control: with the approaching subcarrier of subcarrier of the end of described communication band, make its weight more little.

5. receiving handling method according to claim 3 is characterized in that, described weighting control is following control: with the approaching sub carrier group of subcarrier of the end of described communication band, make its weight more little.

6. according to each described receiving handling method in the claim 2～5, it is characterized in that, control sub-carrier number as the object of described weighting control according to the measurement result of the multidiameter propagation of received signal.

7. according to each described receiving handling method in the claim 2～5, it is characterized in that, be controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the multidiameter propagation of received signal.

8. according to each described receiving handling method in the claim 2～5,7, it is characterized in that, be controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the reception quality information of received signal.

9. receiving handling method according to claim 2, it is characterized in that, under the time dependent situation of the subcarrier that described known received signal is shone upon, according to mapping status separately, control is as the either party or the both sides of the subcarrier of the object of described weighting control and the weight coefficient that uses in described weighting control.

10. receiving handling method according to claim 2 is characterized in that, when existing under the situation of a plurality of sub carrier group across the one or more subcarriers that do not send in described communication band, implements described weighting control according to described sub carrier group.

11. receiving system corresponding with multicarrier, this receiving system receives the 1st sub carrier group and the 2nd sub carrier group, the 1st sub carrier group is corresponding to a plurality of subcarriers that send the known signal be used to obtain the propagation path estimated value respectively, the 2nd sub carrier group is corresponding to sending a plurality of subcarriers of having implemented the data-signal of propagation path compensation according to the propagation path estimated value of using described known signal to obtain respectively, described receiving system is characterised in that to have:

Control part, it carries out following control, reliability of signals after making reliability of signals after the relevant propagation path compensation of the 1st subcarrier than the relevant propagation path compensation of the 2nd subcarrier is low, described the 1st subcarrier has highest frequency in the frequency that is sandwiched in the subcarrier that belongs to described the 1st sub carrier group and the frequency the frequency band between the low-limit frequency, and belong to described the 2nd sub carrier group, described the 2nd subcarrier has the frequency in this frequency band, and belongs to described the 2nd sub carrier group; With

Error correction portion, it carries out correction process based on the reliability of having carried out described control for the signal after the propagation path compensation of relevant described the 1st subcarrier and described the 2nd subcarrier.

12. the receiving system in the multi-carrier communication, this receiving system is characterised in that to have:

Propagation path estimation portion, it generates the propagation path estimated value of each subcarrier according to the known received signal in the scheduled communication frequency band;

Propagation path compensation section, it uses described propagation path estimated value that the reception data-signal that is mapped to any subcarrier is carried out propagation path compensation;

The reliability information generating unit, it obtains the reliability information of the described reception data-signal after the described propagation path compensation;

Weighting control portion, it is weighted control, than the subcarrier that other subcarrier lacks, make the weight of the reliability information that obtains about these subcarriers littler for the quantity of the described known received signal that is used to ask for described propagation path estimated value than the weight of the reliability information that obtains about other subcarrier; With

Error correction portion, it uses the reliability information after the described weighting control to carry out the error correction of described data-signal.

13. receiving system according to claim 12 is characterized in that, described weighting control portion is made as the object of described weighting control the reliability information that obtains at the subcarrier of the end of described communication band or this subcarrier and near subcarrier thereof.

14. receiving system according to claim 13 is characterized in that, described weighting control portion carries out following control: with the approaching subcarrier of subcarrier of the end of described communication band, make its weight more little.

15. receiving system according to claim 13 is characterized in that, described weighting control portion carries out following control: with the approaching sub carrier group of subcarrier of the end of described communication band, make its weight more little.

16., it is characterized in that described weighting control portion is according to the measurement result of the multidiameter propagation of received signal according to each described receiving system in the claim 12～15, control is as the number of subcarriers of the object of described weighting control.

17., it is characterized in that described weighting control portion is controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the multidiameter propagation of received signal according to each described receiving system in the claim 12～15.

18., it is characterized in that described weighting control portion is controlled at the weight coefficient that uses in the described weighting control according to the measurement result of the reception quality information of received signal according to each described receiving system in the claim 12～15,17.

19. receiving system according to claim 12, it is characterized in that, under the time dependent situation of the subcarrier that described known received signal is shone upon, described weighting control portion is according to separately mapping status, and control is as the either party or the both sides of the subcarrier of the object of described weighting control and the weight coefficient that uses in described weighting control.

20. receiving system according to claim 12, it is characterized in that, when existing under the situation of a plurality of sub carrier group across the one or more subcarriers that do not send in described communication band, described weighting control portion implements weighting control according to described sub carrier group.

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