CN101227445B - Method for computing carrier jamming noise ratio under OFDM - Google Patents

Abstract

The invention discloses a method for measuring carrier interference noise ratio under orthogonal frequency division multiplexing, which comprises getting a plurality of pilot subcarrier groups through choosing composition modes of pilot subcarrier groups in a plurality of time-frequency unit, calculating channel response value of pilot subcarrier of the pilot subcarrier groups to each pilot subcarrier group, calculating signal efficiency which is corresponded with the channel response value of the pilot subcarrier groups and disturbance and noise efficiency according to the channel response value according to the pilot subcarrier, calculating to get carrier interference noise ratio according to the sum of signal efficiencies of a plurality of pilot subcarriers and the sum of the disturbance and noise efficiency of the pilot subcarrier groups. The invention overcomes the shortcomings that in the prior art, the calculation of carrier interference noise ratio which is caused by frequency which is selective fading and channel time-varying is accurate through processing pilot frequency signals which are received on the adjacent pilot subcarriers.

Description

A kind of method of under OFDM, calculating the carrier-in-interference noise ratio

Technical field

The present invention relates to communication technical field, relate in particular to a kind of method of under OFDM, calculating the carrier-in-interference noise ratio.

Background technology

In the last few years, OFDM (OFDM) technology had been used to carry out high-speed data transmission by the wire/wireless channel.The OFDM technology converts the serial data of input the data of parallel transmission to, and this parallel data is modulated on a plurality of subcarriers, promptly has the subchannel of orthogonality, then the data after the transmission modulation.

This OFDM technology is widely applied to digital transmission technology, as numeral/audio broadcasting, and digital TV, wireless lan (wlan), wireless asynchronous transfer mode (WATM), broadband wireless access (BWA) etc.

Based on the system of OFDM technology, a very important reference index in carrying out the control of AMC (adaptive coding and modulating) and power is exactly the CINR (carrier-in-interference noise ratio) that is used for reflecting channel quality.For the OFDM symbol that receives, the gross power on each subcarrier can be divided into two parts, and a part is a signal power, and another part is an interference plus noise power.

At present, a kind of method of estimation of carrying out the carrier-in-interference noise ratio being arranged in the prior art, is example based on the up PUSC pattern of the communication system of 802.16e standard.

The running time-frequency resource that a up user is assigned to is divided into a plurality of time frequency unit (tile), and the time frequency unit structure is seen Fig. 1, comprises 12 subcarriers among the tile altogether, 4 pilot sub-carriers is wherein arranged, 8 data subcarriers.Wherein comprise pilot sub-carrier in the first, three OFDM symbol, all subcarriers are data subcarrier in second OFDM symbol.As shown in Figure 1, wherein P represents pilot sub-carrier, the D representative data.By among Fig. 1 as can be seen, P ₁And P ₂Be the pilot tone in first OFDM symbol, P ₃And P ₄Be the 3rd pilot sub-carrier in the OFDM symbol.Remaining subcarrier is data (D ₁～D ₈).Set P ₁And P ₂On the signal that receives be Y ₁And Y ₂, corresponding transmitted signals is X ₁And X ₂

This method is found the solution E[|H by the following method ₁| ²]

$E\left[\right|Y_1\·{Y_2}^{*}\left|\right]=E\left[\right|H_1{H}_2^{*}+H_1{\mathrm{NI}}_2^{*}+H_2^{*}{\mathrm{NI}}_1+H_1{\mathrm{NI}}_2^{*}\left|\right]$

Because hypothesis H ₁=H ₂, following formula can be reduced to

$E\left[\right|\mathrm{real}(Y_1\·{Y_2}^{*})\left|\right]=E\left[\right|\mathrm{real}({\left|H_1\right|}^2+H_1{\mathrm{NI}}_2^{*}+H_2^{*}{\mathrm{NI}}_1+{\mathrm{IN}}_1{\mathrm{NI}}_2^{*})\left|\right]$

$=E\left[\right|{\left|H_1\right|}^2+\mathrm{real}(H_1{\mathrm{NI}}_2^{*}+H_2^{*}{\mathrm{NI}}_1+{\mathrm{NI}}_1{\mathrm{NI}}_2^{*})\left|\right]$

Can think that interference and noise all are 0 average and random distribution, then approximate have

$E\left[\right|\mathrm{real}(Y_1\·{Y_2}^{*})\left|\right]\≈E\left[{\left|H_1\right|}^2\right]=E\left[{\left|H_1{X}_1\right|}^2\right]$

Then the estimator of CINR is:

$\widehat{\mathrm{CINR}}=\frac{E\left[\right|\mathrm{real}(Y_1\·{Y_2}^{*})\left|\right]}{E\left[{\left|Y\right|}^2\right]-E\left[\mathrm{real}\left(\right|Y_1\·{Y_2}^{*}\left|\right)\right]}$

$=\frac{2\·\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}\left|\mathrm{real}(Y_1\left(m\right)\·{Y_2}^{*}\left(m\right))\right|}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-2\·\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}\left|\mathrm{real}(Y_1\left(m\right)\·{Y_2}^{*}\left(m\right))\right|}$

This technology is that the channel in hypothesis signal experience is to ignore to carry out CINR under the condition of influence of frequency selective fading and estimate.Do not exist at channel under the situation of frequency selection decline, the CINR estimated value ratio of precision that obtains is higher.But usually all there is frequency selective fading in the channel that experienced of signal, and that the existence of frequency selective fading can cause estimating signal power is less than normal, therefore can make the estimated value of final carrier-in-interference noise ratio compare less than normal with actual value.Frequency selective fading is serious more, and the error of the estimated value of carrier-in-interference noise ratio will be big more.

Patent " CN1917501A " provide a kind of method: this method is by choosing a plurality of subcarriers and grouping, and the subcarrier that comprises equal number in each sub carrier group is right; Utilize subcarrier in the sub carrier group in each sub carrier group to the interference noise power of the domain channel response value of estimating each sub carrier group sub-carriers respectively; According to the rule of the frequency domain channel response linear variation of described subcarrier, eliminate in the described interference noise power and change the estimation error that is caused by domain channel response; Interference noise power according to the domain channel response value of eliminating the described sub carrier group sub-carriers after the error calculates the carrier-in-interference noise ratio.The present invention can terminal through last become or the time during constant channel, accurately measure the carrier-in-interference noise ratio, reach and make full use of the higher subchannel of carrier-in-interference noise ratio, improve the purpose of systematic function.But this invention only is used for descending cluster structure, and purpose of design only is in order to resist time varying channel, and is powerless for frequency selective fading channels, and design complexities is higher, and effect is undesirable in the practical application.

Patent " WO2007/021159A2 " provide a kind of method: this invention is by utilizing the rule of subcarrier upper signal channel response change adjacent on the preamble sequence, and interference noise is that the thought of the Gaussian random variable of 0 average comes noise jamming is averaged, make it to trend towards 0, the CINR that obtains system estimates.Because this method only can be used for the preamble sequence, the default channel response does not change in a big way, and the certainty of measurement of CINR is affected, and effect is relatively poor in frequency selective fading channels.

Summary of the invention

The invention provides a kind of method of under OFDM, calculating the carrier-in-interference noise ratio, calculate the problem of can not the decline of contrary frequency selectivity and becoming during channel in order to solve the carrier-in-interference noise ratio that exists in the prior art.

The inventive method comprises:

Steps A: in a plurality of time frequency unit, choose one or two pilot subcarrier sets respectively, obtain a plurality of pilot subcarrier sets; Under non-NULL divides mode, in each time frequency unit, choose two pilot subcarrier sets, and two pilot tones in the described pilot subcarrier sets are on the pilot sub-carrier position of the diverse location on the same OFDM symbol, perhaps, two pilot tones in the described pilot subcarrier sets are on the pilot sub-carrier position of the same position on the different orthogonal frequency division multiplexing symbol; Under sky branch mode, in each time frequency unit, choose a pilot subcarrier sets, and two pilot tones in the described pilot subcarrier sets are respectively on the pilot sub-carrier position of the diverse location on first OFDM symbol and the 3rd OFDM symbol;

Step B:, calculate the channel response value of the pilot sub-carrier of described pilot subcarrier sets for each pilot subcarrier sets; The channel response value of wherein calculating the pilot sub-carrier of described pilot subcarrier sets specifically comprises: step B1: for two pilot sub-carrier P of described pilot subcarrier sets ₁And P ₂If set P ₁And P ₂On the pilot signal that receives be Y ₁And Y ₂, the pilot signal of the transmission of corresponding transmitting terminal is X ₁And X ₂, the respective channel response is H ₁And H ₂, disturb and to be I ₁And I ₂, noise is N ₁And N ₂, then have following formula to set up: Y ₁=H ₁X ₁+ N ₁+ I ₁, Y ₂=H ₂X ₂+ N ₂+ I ₂Step B2: the formula among the step B1 respectively divided by the pilot signal of corresponding transmitting terminal, is obtained following formula:

N wherein ₁+ I ₁, N ₂+ I ₂It is the Gaussian random variable of 0 average; Step B3: the channel response value H that the formula among the step B2 is carried out obtaining after the approximate processing two pilot signals ₁And H ₂, that is,

Step C:, calculate the signal power of the channel response value correspondence of described pilot subcarrier sets according to the channel response value of described pilot sub-carrier; The signal power of wherein calculating the channel response value correspondence of described pilot subcarrier sets specifically comprises: step C1: for a plurality of pilot subcarrier sets of choosing, calculate the signal power of described pilot subcarrier sets respectively according to following formula,

Wherein, NI ₁Expression N ₁+ I ₁, NI ₂Expression N ₂+ I ₂Step C2: because H ₁And H ₂Value identical, then the simplified formula among the step C1 is: E[Y ₁X ₁(Y ₂X ₂) ^*]=E[|H ₁| ²];

Step D: the gross power of the channel response value correspondence of all pilot sub-carrier correspondences in described a plurality of pilot subcarrier sets that will calculate, deduct described a plurality of pilot subcarrier sets signal power and, obtain described a plurality of pilot subcarrier sets interference plus noise power and; According to the signal power of described a plurality of pilot subcarrier sets and, and the interference plus noise power of described a plurality of pilot subcarrier sets and, with the signal power of described a plurality of pilot subcarrier sets and with the interference plus noise power of described a plurality of pilot subcarrier sets be divided by and calculate the carrier-in-interference noise ratio.

Further, under non-NULL divided mode, described carrier-in-interference noise ratio calculated by following formula:

$\widehat{\mathrm{CINR}}=\frac{|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|\·2}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·{X_1\left(k\right)\·(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|\·2};$

Under sky branch mode, described carrier-in-interference noise ratio calculates by following formula:

$\widehat{\mathrm{CINR}}=\frac{|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·{X_1\left(k\right)\·(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|},$ Wherein, K is the number of time frequency unit.

Beneficial effect of the present invention is as follows: the present invention is according to the characteristics of ofdm system, by processing to the pilot signal received on the adjacent pilot frequencies subcarrier, overcome the carrier-in-interference noise ratio that causes that becomes during owing to frequency selective fading and channel of the prior art and calculated inaccurate shortcoming, solved the carrier-in-interference noise ratio that exists in the prior art and calculate the problem of can not the decline of contrary frequency selectivity and becoming during channel

Description of drawings

Fig. 1 divides the structural representation of the time frequency unit under the mode for the present invention at non-NULL;

Fig. 2 is the schematic flow sheet of the described method of the embodiment of the invention;

Fig. 3 is the structural representation of the time frequency unit of the present invention under sky branch mode.

Embodiment

Below in conjunction with accompanying drawing the described method of the embodiment of the invention is elaborated.

At first the described method of first embodiment of the invention is elaborated.

As shown in Figure 1, Fig. 1 is the time frequency unit structural representation under the up PUSC pattern of 802.16e.A tile is a time frequency unit, comprises 12 subcarriers among the tile altogether, 4 pilot sub-carriers is wherein arranged, 8 data subcarriers.Wherein comprise pilot sub-carrier among first OFDM symbol and the 3rd, all subcarriers are data subcarrier in second OFDM symbol.Wherein, P represents pilot sub-carrier, D representative data subcarrier.By among Fig. 1 as can be seen, P ₁And P ₂Be the pilot sub-carrier in first OFDM symbol, P ₃And P ₄Be the 3rd pilot sub-carrier in the OFDM symbol, remaining subcarrier is data (D ₁～D ₈).

As shown in Figure 2, Fig. 2 is under non-NULL divides mode, and the schematic flow sheet of the described method of first embodiment of the invention specifically can may further comprise the steps:

Step 201: divide into groups according to the decline situation of channel pilot sub-carrier to time frequency unit, pilot sub-carrier in the principle of grouping tries hard to make one group is within the scope of channel fading or during channel within the change scope, promptly by choosing the pilot tone on the different sub carrier on the same OFDM symbol, the position of the same pilot sub-carrier on the perhaps different OFDM symbols.Such as, if P ₁And P ₂One group, P so ₃And P ₄Must be one group; If P ₁And P ₃One group, P so ₂And P ₄Must be one group, in the present embodiment with P ₁And P ₂One group is that example describes.

Step 202:, get corresponding channel response value by the pilot sub-carrier in the pilot subcarrier sets of choosing is handled.Be exactly specifically, if set P ₁And P ₂On the pilot signal that receives be Y ₁And Y ₂, the pilot signal of corresponding transmitting terminal is X ₁And X ₂, then for two pilot signal Y that receive on first OFDM symbol ₁And Y ₂, have following formula to set up:

Y ₁＝H ₁X ₁+N ₁+I ₁ (1)

Y ₂＝H ₂X ₂+N ₂+I ₂ (2)

Wherein, H ₁Be the pilot signal X that sends ₁Through the channel response of channel, H ₂Be the pilot signal X that sends ₂Through the channel response of channel, N ₁+ I ₁Be X ₁Through the interference plus noise power of channel, N ₂+ I ₂Be X ₂Interference plus noise power through channel.

Because transmitting-receiving two-end all keeps the data that the pilot sub-carrier place sends, so can carry out following processing to the pilot tone that receives in receiving end:

$\frac{Y_1}{X_1}=H_1+\frac{N_1+I_1}{X_1}---\left(3\right)$

$\frac{Y_2}{X_2}=H_2+\frac{N_2+I_2}{X_2}---\left(4\right)$

Because N ₁+ I ₁Be the Gaussian random variable of 0 average, so can think

Be one and be tending towards 0 Gaussian random variable, in like manner, N ₂+ I ₂Also be the Gaussian random variable of 0 average, so

Also be one and be tending towards 0 Gaussian random variable, channel response value is had following approximate then according to formula (3) and (4):

$H_1\≈\frac{Y_1}{X_1}---\left(5\right)$

$H_2\≈\frac{Y_2}{X_2}---\left(6\right).$

Step 203: for according to each pilot subcarrier sets of choosing in the step 201, for two pilot signals in the pilot subcarrier sets according to formula E[Y ₁X ₁(Y ₂X ₂) ^*] calculate, obtain the signal power in this pilot subcarrier sets, make NI=N+I, X ₁=1 or-1, then with E[Y ₁X ₁(Y ₂X ₂) ^*] can obtain after the expansion:

$E[Y_1\·X_1\·{(Y_2\·X_2)}^{*}]=E\left[H_1{H}_2^{*}\right]+E\left[H_1{\mathrm{NI}}_2^{*}\right]+E\left[H_2^{*}{\mathrm{NI}}_1\right]+E\left[H_1{\mathrm{NI}}_2^{*}\right]---\left(7\right),$

Because in the tile structure, we ignore the variation of the channel response value on an OFDM symbol, think that two pilot sub-carrier upper signal channel responses on a symbol are identical, so can think H in the formula (7) ₁And H ₂Be worth identical, that is, and H ₁=H ₂Again because the signal on the different carrier, noise and to disturb all be separate, X (k) be that BPSK (two-phase PSK) modulates, and N+I is the Gaussian random variable of 0 average, so can obtain by formula (7):

E[Y ₁·X ₁·(Y ₂·X ₂) ^*]≈E[|H ₁| ²] (8)。

Because at 802.16e, the data that send under the PUSC pattern are made of a plurality of tile structures, each tile comprises two pilot subcarrier sets again, when calculating, need sue for peace like this for the signal power of a plurality of pilot subcarrier sets, obtain all pilot subcarrier sets signal power and, promptly

Wherein, K represents the number of time frequency unit;

Step 204: calculating all subcarriers in all sub carrier group to the gross power of deserved domain channel response value correspondence is

Because gross power can be divided into two parts, a part be signal power and, another part be interference power plus noise power and, so deduct with gross power all pilot subcarrier sets interference plus noise power signal power and that just obtain all pilot subcarrier sets and;

Step 205: the carrier-in-interference noise ratio of calculating the frequency domain channel estimated value of all subcarrier correspondences, be described carrier-in-interference noise ratio=all pilot subcarrier sets signal power and/interference plus noise power of all pilot subcarrier sets and, be formulated as:

$\widehat{\mathrm{CINR}}=\frac{|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|\·2}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·{X_1\left(k\right)\·(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|\·2}---\left(9\right)$

Below the described method of second embodiment of the invention is elaborated.

When system is empty branch mode, transmit data under the PUSC mode, supposing the system is configured to two reception antennas of two transmit antennas, sends user 1 data so on the antenna 1, sends user 2 data on the antenna 2.At this time the user data pilot number on each antenna reduces by half.Be that example is described this implementation method with user 1 now, user 2 situation and user 1 are similar, no longer repeat.

When system is empty branch mode, when transmitting data under the PUSC mode, the structure of time frequency unit as shown in Figure 3, Fig. 3 has provided the structure of user 1 time frequency unit, comprises 12 subcarriers in the time frequency unit altogether, 2 pilot sub-carriers is wherein arranged, 8 data subcarriers.Wherein respectively comprise a pilot sub-carrier among first OFDM symbol and the 3rd, all subcarriers are data subcarrier in second OFDM symbol.As shown in Figure 4, wherein P represents pilot sub-carrier, D representative data subcarrier.By among Fig. 3 as can be seen, P ₁Be the pilot tone in first OFDM symbol, P ₂Be the 3rd pilot sub-carrier in the OFDM symbol.Remaining subcarrier is data (D ₁～D ₈).Set P ₁And P ₂On the signal that receives be Y ₁And Y ₂Corresponding transmitted signals is X ₁And X ₂These two pilot sub-carriers are divided into one group, pilot tone are handled according to the embodiment that Fig. 3 describes.

By to the pilot sub-carrier P in the pilot subcarrier sets of choosing ₁And P ₂Handle, obtain corresponding channel response value.

For the pilot signal Y that receives on first OFDM symbol ₁With the pilot signal Y that receives on the 3rd the OFDM symbol ₂, have following formula to set up.

Y ₁＝H ₁X ₁+N ₁+I ₁ (10)

Y ₂＝H ₂X ₂+N ₂+I ₂ (11)

Because transmitting-receiving two-end all keeps the data that the pilot sub-carrier place sends, so can do following processing to the pilot signal that receives in receiving end:

$\frac{Y_1}{X_1}=H_1+\frac{N_1+I_1}{X_1}---\left(12\right)$

$\frac{Y_2}{X_2}=H_2+\frac{N_2+I_2}{X_2}---\left(13\right)$

Because N ₁+ I ₁Be the Gaussian random variable of 0 average, so can think Be one and be tending towards 0 Gaussian random variable, in like manner, N ₂+ I ₂Also be the Gaussian random variable of 0 average, so Also be one and be tending towards 0 Gaussian random variable have following approximate for channel response value.

$H_1\≈\frac{Y_1}{X_1}---\left(14\right)$

$H_2\≈\frac{Y_2}{X_2}---\left(15\right)$

According to selected pilot subcarrier sets, calculate the signal power of pilot subcarrier sets respectively

$E[Y_1\·X_1\·{(Y_2\·X_2)}^{*}]=E\left[H_1{H}_2^{*}\right]+E\left[H_1{\mathrm{NI}}_2^{*}\right]+E\left[H_2^{*}{\mathrm{NI}}_1\right]+E\left[H_1{\mathrm{NI}}_2^{*}\right]---\left(16\right)$

Because in empty separation structure, a certain user only takies two pilot signals in each tile structure, lay respectively at first OFDM symbol and the 3rd OFDM symbol, so can only think pilot signal on first OFDM symbol, identical with the pilot sub-carrier upper signal channel response on the 3rd the OFDM symbol, so can think H in the following formula ₁And H ₂Be worth identical, that is, and H ₁=H ₂Again because the signal on the different carrier, noise and to disturb all be separate, X (k) be that BPSK (two-phase PSK) modulates, and N+I is the Gaussian random variable of 0 average, so can be obtained by formula (16)

E[Y ₁·X ₁·(Y ₂·X ₂) ^*]＝E[|H ₁| ²] (17)

Because at 802.16e, the data that the empty merotype of PUSC sends down are made of a plurality of tile structures, each tile comprises a pilot subcarrier sets again, when calculating, need sue for peace like this for the signal power of a plurality of pilot subcarrier sets, obtain all pilot subcarrier sets signal power and, promptly Wherein, K represents the number of time frequency unit;

Finally, obtain following CINR and measure formula:

$\widehat{\mathrm{CINR}}=\frac{|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·{X_1\left(k\right)\·(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|}---\left(18\right)$

In sum, the invention provides a kind of method of under OFDM, calculating the carrier-in-interference noise ratio, characteristics according to ofdm system, by processing to the pilot signal received on the adjacent pilot frequencies subcarrier, obtain the signal power on the pilot sub-carrier comparatively accurately, and then calculate the carrier-in-interference noise ratio.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claims.

Claims (2)

1. a method of measuring the carrier-in-interference noise ratio under OFDM is characterized in that, comprising:

Steps A: in a plurality of time frequency unit, choose one or two pilot subcarrier sets respectively, obtain a plurality of pilot subcarrier sets; Under non-NULL divides mode, in each time frequency unit, choose two pilot subcarrier sets, and two pilot tones in the described pilot subcarrier sets are on the pilot sub-carrier position of the diverse location on the same OFDM symbol, perhaps, two pilot tones in the described pilot subcarrier sets are on the pilot sub-carrier position of the same position on the different orthogonal frequency division multiplexing symbol; Under sky branch mode, in each time frequency unit, choose a pilot subcarrier sets, and two pilot tones in the described pilot subcarrier sets are respectively on the pilot sub-carrier position of the diverse location on first OFDM symbol and the 3rd OFDM symbol;

Step B:, calculate the channel response value of the pilot sub-carrier of described pilot subcarrier sets for each pilot subcarrier sets; The channel response value of wherein calculating the pilot sub-carrier of described pilot subcarrier sets specifically comprises: step B1: for two pilot sub-carrier P of described pilot subcarrier sets ₁And P ₂If set P ₁And P ₂On the pilot signal that receives be Y ₁And Y ₂, the pilot signal of the transmission of corresponding transmitting terminal is X ₁And X ₂, the respective channel response is H ₁And H ₂, disturb and to be I ₁And I ₂, noise is N ₁And N ₂, then have following formula to set up: Y ₁=H ₁X ₁+ N ₁+ I ₁, Y ₂=H ₂X ₂+ N ₂+ I ₂Step B2: the formula among the step B1 respectively divided by the pilot signal of corresponding transmitting terminal, is obtained following formula:

N wherein ₁+ I ₁, N ₂+ I ₂It is the Gaussian random variable of 0 average; Step B3: the channel response value H that the formula among the step B2 is carried out obtaining after the approximate processing two pilot signals ₁And H ₂, that is,

Step C:, calculate the signal power of the channel response value correspondence of described pilot subcarrier sets according to the channel response value of described pilot sub-carrier; The signal power of wherein calculating the channel response value correspondence of described pilot subcarrier sets specifically comprises: step C1: for a plurality of pilot subcarrier sets of choosing, calculate the signal power of described pilot subcarrier sets respectively according to following formula,

Wherein, NI ₁Expression N ₁+ I ₁, NI ₂Expression N ₂+ I ₂Step C2: because H ₁And H ₂Value identical, then the simplified formula among the step C1 is: E[Y ₁X ₁(Y ₂X ₂) ^*]=E[|H ₁| ²];

Step D: the gross power of the channel response value correspondence of all pilot sub-carrier correspondences in described a plurality of pilot subcarrier sets that will calculate, deduct described a plurality of pilot subcarrier sets signal power and, obtain described a plurality of pilot subcarrier sets interference plus noise power and; According to the signal power of described a plurality of pilot subcarrier sets and, and the interference plus noise power of described a plurality of pilot subcarrier sets and, with the signal power of described a plurality of pilot subcarrier sets and with the interference plus noise power of described a plurality of pilot subcarrier sets be divided by and calculate the carrier-in-interference noise ratio.

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

Under non-NULL divided mode, described carrier-in-interference noise ratio calculated by following formula:

$\widehat{\mathrm{CINR}}=\frac{|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|\·2}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|\·2};$

Under sky branch mode, described carrier-in-interference noise ratio calculates by following formula:

$\widehat{\mathrm{CINR}}=\frac{|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|Y\left(k\right)\right|}^2-|\underset{k=1}{\overset{K/2}{\mathrm{\Σ}}}{Y}_1\left(k\right)\·X_1\left(k\right)\·{(Y_2\left(k\right)\·X_2\left(k\right))}^{*}|},$ Wherein, K is the number of time frequency unit.

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