CN101729462B - Method for comprehensively measuring and calculating carrier to interference plus noise ratio in orthogonal frequency division multiplexing - Google Patents

Abstract

The invention discloses a method for comprehensively measuring and calculating carrier to interference plus noise ratio in orthogonal frequency division multiplexing, which comprises the following steps: measuring reference symbols in a resource block, using the reference symbols to constitute a reference symbol resource unit group and calculating the signal channel response value thereof; calculating signal power which corresponds to the reference symbol resource unit group according to the signal channel response value; measuring total power of the reference symbol resource unit group which corresponds to the signal channel reference value and obtaining the corresponding interference plus noise power; and calculating the carrier to interference plus noise ratio according to the ratio of the sum of a plurality of signal powers of the reference symbol resource unit group to the sum of a plurality of interference plus noise powers of the reference symbol resource unit group. The method processes the interference plus noise powers of the reference symbol signals received on the adjacent reference symbol resource units, thereby overcoming the shortcoming of inaccurate measurement and calculation of the carrier to interference plus noise ratio caused by frequency selective fading and signal channel time variation and solving the problem that the measurement and the calculation of the carrier to interference plus noise ratio can not resist the frequency selective fading and the signal channel time variation.

Description

A kind of in OFDM the method for comprehensively measuring and calculating carrier-in-interference noise ratio

Technical field

The present invention relates to the digital transmission technology field, in particular a kind of in OFDM the method improvement of comprehensively measuring and calculating carrier-in-interference noise ratio.

Background technology

In the last few years, OFDM (Orthogonal Frequency Division Multiplexing is hereinafter to be referred as OFDM) orthogonal frequency division multiplexi had been widely used in carrying out transfer of data at a high speed by the wire/wireless channel.The orthogonal frequency division multiplex OFDM technology converts the serial data of input the data of parallel transmission to, and this parallel data is modulated on a plurality of Resource Units, also namely has on the subchannel of orthogonality, then the data after the transmission modulation.

This orthogonal frequency division multiplex OFDM technology is widely used in digital transmission technology field, for example numeral/audio broadcasting, digital TV, WLAN (wireless local area network) WLAN, wireless asynchronous transfer mode WATM or broadband wireless access BWA etc.

Take the system of orthogonal frequency division multiplex OFDM technology as the basis, in carrying out the control of adaptive coding and modulating AMC and power, it is exactly CINR (Carrier to Interference+Noise Ratio is hereinafter to be referred as CINR) the carrier-in-interference noise ratio that reflects channel quality that a very important reference index is arranged.And for the orthogonal frequency division multiplex OFDM symbol that receives, the gross power on each Resource Unit can be divided into two parts, and a part is signal power, and another part is interference plus noise power.

Mention a kind of method in the Chinese patent of application number 200610127279.5 " a kind of method of measurement of carrier-in-interference noise ratio and device ", the method is by measuring a plurality of Resource Units and grouping, comprises the Resource Unit pair of equal number in each resource unit group; Utilize respectively Resource Unit in the resource unit group in each resource unit group to the interference noise power of the domain channel response value of estimating Resource Unit in each resource unit group; According to the rule of the frequency domain channel response linear variation of described Resource Unit, eliminate in described interference noise power and change by domain channel response the estimation error that causes; Interference noise power according to the domain channel response value of Resource Unit in the described resource unit group after the elimination 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 take full advantage of the higher subchannel of carrier-in-interference noise ratio, improve the purpose of systematic function.But should invention only be used for descending structure, purpose of design is only in order to resist time varying channel, and is helpless for frequency selective fading channels, and design complexities is higher, and in practical application, effect is unsatisfactory.

Also mention another kind of method in patent " WO2007/021159A2 ", the method is by utilizing the rule of Resource Unit upper signal channel response change adjacent on targeting sequencing, and interference noise is that the thought of the Gaussian random variable of zero-mean averages noise jamming, make it to trend towards zero, the CINR carrier-in-interference noise ratio that obtains system is estimated.Because this method also only can be used for targeting sequencing, and the default channel response does not change in a big way, and the precision of the measurement of CINR carrier-in-interference noise ratio can be affected, and effect is also relatively poor in frequency selective fading channels.

Therefore, prior art still awaits improving and development.

Summary of the invention

The object of the invention is to, provide a kind of in OFDM the method for comprehensively measuring and calculating carrier-in-interference noise ratio, in order to solve at LTE (Long Term Evolution, hereinafter to be referred as LTE) in the process of down link comprehensively measuring and calculating carrier-in-interference noise ratio, the problem that becomes when contrary frequency selectivity decline simultaneously and channel.

Technical scheme of the present invention is as follows:

A kind of in OFDM the method for comprehensively measuring and calculating carrier-in-interference noise ratio, comprise the following steps:

A, in Resource Block the witness mark symbol, and this reference symbol is formed the reference symbol resource unit group, calculate its channel response value;

B, calculate the signal power of corresponding reference symbol resource unit group according to described channel response value;

C, reference symbol resource unit group gross power corresponding to the described channel response value of measurement obtain corresponding interference plus noise power;

D, obtain the carrier-in-interference noise ratio by the ratio calculation of the interference plus noise power sum of the signal power sum of a plurality of reference symbol resource unit group and a plurality of reference symbol resource unit group.

Described method, wherein, in described steps A, the witness mark symbol comprises:

Selective measurement belongs to same OFDM symbol but is positioned at the locational reference symbol of different reference symbol Resource Units in Resource Block.

Described method wherein, forms the reference symbol resource unit group and comprises in described steps A:

Reference symbol on each OFDM symbol is set as one group of reference symbol resource unit group.

Described method, wherein, in described steps A, the witness mark symbol specifically comprises following at least a mode:

Choose a plurality of reference symbol resource unit group in a Resource Block, form a plurality of reference symbol resource unit group;

Choose respectively a reference symbol resource unit group in a plurality of Resource Block, form a plurality of reference symbol resource unit group;

Choose respectively a plurality of reference symbol resource unit group in a plurality of Resource Block, form a plurality of reference symbol resource unit group.

Described method, wherein, described steps A also comprises:

Two reference symbols on same OFDM symbol in the single resource piece are P ₁And P ₂The time, described P ₁And P ₂On the reference symbol signal Y that receives ₁And Y ₂Calculate according to following formula and obtain:

Y ₁＝H ₁X ₁+N ₁+I ₁，Y ₂＝H ₂X ₂+N ₂+I ₂，

Wherein, channel response value is H ₁And H ₂, corresponding transmitting terminal the reference symbol signal be X ₁And X ₂, corresponding interference signal is I ₁And I ₂, corresponding noise signal is N ₁And N ₂

Described method, wherein, channel response value H described in described steps A ₁And H ₂Obtain according to following formula:

$\frac{Y_1}{X_1}=H_1+\frac{N_1+I_1}{X_1},\frac{Y_2}{X_2}=H_2+\frac{N_2+I_2}{X_2}.$

Described method, wherein, described steps A also comprises:

As described N ₁+ I ₁, N ₂+ I ₂During for the Gaussian random variable of zero-mean, P ₁And P ₂Channel response value H after approximate processing ₁And H ₂Obtain according to following formula:

$H_1\≈\frac{Y_1}{X_1},$ $H_2\≈\frac{Y_2}{X_2}.$

Described method, wherein, described step B specifically comprises:

Described P ₁And P ₂On signal power calculate according to following formula and obtain:

$E[(Y_1/X_1)\·{(Y_2/X_2)}^{*}]=$

$E\left[H_1{H}_2^{*}\right]+E[H_1\·{\left(\frac{N_2+I_2}{X_2}\right)}^{*}]+E[H_2^{*}\·\left(\frac{N_1+I_1}{X_1}\right)]+E[\left(\frac{N_1+I_1}{X_1}\right)\·{\left(\frac{N_2+I_2}{X_2}\right)}^{*}].$

Described method, wherein, described step B also comprises:

Described N ₁+ I ₁, N ₂+ I ₂Be the Gaussian random variable of zero-mean, and described channel response value H ₁And H ₂Value when identical, P ₁And P ₂Signal power after approximate processing obtains according to following formula:

E[(Y ₁/X ₁)·(Y ₂/X ₂) ^*]＝E[|H ₁| ²]

Described method, wherein, described step D specifically comprises:

Obtain the carrier-in-interference noise ratio according to following formula:

$C\widehat{\mathrm{IN}}R=\frac{|\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}(Y_1\left(k\right)/X_1\left(k\right))\·{(Y_2\left(k\right)/X_2\left(k\right))}^{*}|\·2}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{|Y\left(k\right)/X\left(k\right)|}^2-|\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}(Y_1\left(k\right)/X_1\left(k\right))\·{(Y_2\left(k\right)/X_2\left(k\right))}^{*}|\·2},$

Wherein, CINR is the carrier-in-interference noise ratio, Y ₁(k) and Y ₂(k) be the reference symbol signal of receiving terminal on two reference symbols on same OFDM symbol in a plurality of Resource Block, the reference symbol signal of corresponding transmitting terminal is X ₁(k) and X ₂(k), Y (k)/X (k) is the gross power of each reference symbol resource unit group in a plurality of Resource Block.

Provided by the present invention a kind of in OFDM the method for comprehensively measuring and calculating carrier-in-interference noise ratio, due to the characteristics according to LTE descending reference allocation of symbols, by the reference symbol signal of receiving on adjacent reference symbol Resource Unit is processed interference plus noise power, the inaccurate shortcoming of carrier-in-interference noise ratio measuring and calculating that becomes when having overcome frequency selective fading of the prior art and channel and cause has solved the problem that becomes when the carrier-in-interference noise ratio that exists in the prior art is calculated contrary frequency selectivity decline simultaneously and channel.

Description of drawings

Fig. 1 is the schematic flow sheet of the method for the invention;

Fig. 2 is the distribution schematic diagram of reference symbol in single resource piece of the present invention.

Embodiment

Below with reference to shown in accompanying drawing, to the present invention a kind of in OFDM embodiment and the embodiment of comprehensively measuring and calculating carrier-in-interference noise ratio described in detail.

The present invention a kind of in OFDM the method for comprehensively measuring and calculating carrier-in-interference noise ratio, it is a kind of method of measuring computing carrier jamming noise ratio in the LTE down link, main core point is, interference plus noise power sum in cumulative a plurality of resource unit group of conjugate multiplication, and calculate the carrier-in-interference noise ratio with appointment with value calculating method; Be well known to those skilled in the art as for knowledge such as LTE, Resource Block, CINR and OFDM technology, do not repeat them here.

Taking it by and large, the embodiment of comprehensively measuring and calculating carrier-in-interference noise ratio is in OFDM, by the building form of selective measurement reference symbol, obtains a plurality of reference symbol groups in a plurality of Resource Block; For each reference symbol group, estimate the channel response value of described reference symbol Resource Unit; According to described channel response value, calculate the signal power corresponding to channel response value of described reference symbol resource unit group again, and interference plus noise power; At last according to a plurality of described signal powers and, and a plurality of described interference plus noise power and, calculate the carrier-in-interference noise ratio.

Specifically, above-mentioned embodiment comprises the following steps as shown in Figure 1:

Step S110, in a plurality of Resource Block by the building form of the one or more reference symbol resource unit group of selective measurement respectively, obtain a plurality of reference symbol resource unit group; Can belong to same orthogonal frequency division multiplexed symbol but be positioned at the locational reference symbol of different reference symbol Resource Units by selective measurement in the single resource piece, also can carry out the described reference symbol of selective measurement in a plurality of Resource Block;

Step S120, the reference symbol on each OFDM symbol is set as one group, for each reference symbol resource unit group, estimates the channel response value of reference symbol Resource Unit in described reference symbol resource unit group;

Step S130, according to described channel response value, calculate signal power corresponding to described channel response value, and further calculate corresponding interference plus noise power by measuring gross power;

Step S140, according to the signal power of described a plurality of reference symbol resource unit group, and the power of the interference plus noise of described a plurality of reference symbol resource unit group, computing carrier jamming noise ratio.

Give an example, two reference symbol resource unit group of selective measurement in the single resource piece, and two reference symbols in described reference symbol resource unit group though belong to same OFDM symbol, are positioned on different reference symbol Resource Units positions; Then, will form the reference symbol resource unit group with the reference symbol of above-mentioned selective measurement, calculate its channel response value.

Take Fig. 2 as example, be laterally a plurality of orthogonal frequency division multiplex OFDM symbol directions in the single resource piece.Reference symbol on each orthogonal frequency division multiplex OFDM symbol is as one group.The witness mark symbol packets is the 1st, the 5, the reference symbol on the 8th, the 12 orthogonal frequency division multiplex OFDM symbol.The reference symbol of selective measurement in one group is called P ₁And P ₂In other words the problem that this kind selective measurement has become when having considered simultaneously frequency selective fading and channel, has laterally considered the frequency selective fading problem, and becomes problem when vertically having considered channel; Can choose a plurality of reference symbol resource unit group in a Resource Block, form a plurality of reference symbol resource unit group; Also can choose respectively a reference symbol resource unit group in a plurality of Resource Block, form a plurality of reference symbol resource unit group; More can choose respectively a plurality of reference symbol resource unit group in a plurality of Resource Block, form a plurality of reference symbol resource unit group.。

At length, in described step S120, the channel response value of the described reference symbol resource unit group of calculating specifically comprises:

Step S121: for two reference symbol P of described reference symbol resource unit group ₁And P ₂If set P ₁And P ₂On the reference symbol signal that receives be Y ₁And Y ₂, the reference symbol signal of corresponding transmitting terminal is X ₁And X ₂, channel response value is H ₁And H ₂, disturb and to be I ₁And I ₂, noise is N ₁And N ₂, have following formula to set up:

Y ₁＝H ₁X ₁+N ₁+I ₁，Y ₂＝H ₂X ₂+N ₂+I ₂。

Step S122: the formula in step S121 respectively divided by the reference symbol signal of corresponding transmitting terminal, is obtained following formula:

$\frac{Y_1}{X_1}=H_1+\frac{N_1+I_1}{X_1},$ $\frac{Y_2}{X_2}=H_2+\frac{N_2+I_2}{X_2},$

N wherein ₁+ I ₁, N ₂+ I ₂It is the Gaussian random variable of zero-mean.

Further, after the approximate processing that the formula in above-mentioned steps S122 is estimated, obtain the channel response value H of two reference symbol signals ₁And H ₂, namely

$H_1\≈\frac{Y_1}{X_1},$ $H_2\≈\frac{Y_2}{X_2}.$

At length, described step S130 specifically comprises:

Step S131: for a plurality of reference symbol resource unit group of selective measurement, respectively according to following formula, conjugate multiplication calculates the signal power in described reference symbol resource unit group,

$E[(Y_1/X_1)\·{(Y_2/X_2)}^{*}]=$

$E\left[H_1{H}_2^{*}\right]+E[H_1\·{\left(\frac{N_2+I_2}{X_2}\right)}^{*}]+E[H_2^{*}\·\left(\frac{N_1+I_1}{X_1}\right)]+E[\left(\frac{N_1+I_1}{X_1}\right)\·{\left(\frac{N_2+I_2}{X_2}\right)}^{*}],$

By the formula of above-mentioned computational methods, to compare with general computational methods, the variation that has become when having taken into account simultaneously frequency selective fading and channel can be calculated the signal power in described reference symbol resource unit group accurately.

Further, due to H ₁And H ₂Value identical, noise item and distracter are the gaussian variables of zero-mean, the simplified formula in above-mentioned steps S131 is:

E[(Y ₁/X ₁)·(Y ₂/X ₂) ^*]＝E[|H ₁| ²]

Step S132: the gross power of all Resource Unit respective signal responses in described a plurality of resource unit group that measuring and calculating is obtained, deduct the signal power sum of described a plurality of resource unit group, obtain the interference plus noise power sum in described a plurality of resource unit group.

At length, described step S140 specifically comprises:

According to the signal power sum of described a plurality of reference symbol resource unit group, and the power sum of the interference plus noise of described a plurality of reference symbol resource unit group, calculate the carrier-in-interference noise ratio by both ratio.

With the comprehensively measuring and calculating of value in can adopt multiple computational methods, basic principle is similar.

Preferably, in described step S142, described carrier-in-interference noise ratio calculates by following formula:

$C\widehat{\mathrm{IN}}R=\frac{|\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}(Y_1\left(k\right)/X_1\left(k\right))\·{(Y_2\left(k\right)/X_2\left(k\right))}^{*}|\·2}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{|Y\left(k\right)/X\left(k\right)|}^2-|\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}(Y_1\left(k\right)/X_1\left(k\right))\·{(Y_2\left(k\right)/X_2\left(k\right))}^{*}|\·2,}.$

Wherein, CINR is the carrier-in-interference noise ratio, Y ₁(k) and Y ₂(k) be the reference symbol signal of receiving terminal on two reference symbols on same OFDM symbol in a plurality of Resource Block, X ₁(k) and X ₂(k) be the reference symbol signal of corresponding transmitting terminal, Y (k)/X (k) is the gross power of each reference symbol resource unit group in a plurality of Resource Block, m=1 to K/2, k=1 to K, K〉0 and be integer.

By the formula of above-mentioned computational methods, compare with general computational methods, under the variation that becomes when taking into account at the same time frequency selective fading and channel, can calculate accurately indeterminable carrier-in-interference noise ratio.

The technology that adopts interference plus noise power to obtain the carrier-in-interference noise ratio in above specific embodiment can adopt existing various possible schemes according to practical application, is well known to those skilled in the art, and also repeats no more at this.

Provide in the specific embodiment of the invention a kind of in OFDM the method for comprehensively measuring and calculating carrier-in-interference noise ratio, due to the characteristics according to LTE descending reference allocation of symbols, by the reference symbol signal of receiving on adjacent reference symbol Resource Unit is processed interference plus noise power, the inaccurate shortcoming of carrier-in-interference noise ratio measuring and calculating that becomes when having overcome frequency selective fading of the prior art and channel and cause has solved the problem that becomes when the carrier-in-interference noise ratio that exists in the prior art is calculated contrary frequency selectivity decline simultaneously and channel.

Should be understood that; for those of ordinary skills; can be improved according to the explanation of such scheme or conversion, for example with the comprehensively measuring and calculating of value in can adopt multiple computational methods, and all these improve and conversion all should belong to the protection range of claims of the present invention.

Claims (3)

1. the method for a comprehensively measuring and calculating carrier-in-interference noise ratio in OFDM comprises the following steps:

A, in Resource Block the witness mark symbol, and this reference symbol is formed the reference symbol resource unit group, calculate its channel response value;

Wherein, the witness mark symbol comprises: selective measurement belongs to same OFDM symbol but is positioned at the locational reference symbol of different reference symbol Resource Units in Resource Block;

Forming the reference symbol resource unit group comprises: the reference symbol on each OFDM symbol is set as one group of reference symbol resource unit group;

The witness mark symbol specifically comprises following at least a mode: choose a plurality of reference symbol resource unit group in a Resource Block, form a plurality of reference symbol resource unit group; Choose respectively a reference symbol resource unit group in a plurality of Resource Block, form a plurality of reference symbol resource unit group; Choose respectively a plurality of reference symbol resource unit group in a plurality of Resource Block, form a plurality of reference symbol resource unit group;

When two reference symbols on same OFDM symbol in the single resource piece were P1 and P2, the reference symbol signal Y1 that receives on described P1 and P2 and Y2 calculated according to following formula and obtain:

Y ₁＝H ₁X ₁+N ₁+I ₁，Y ₂＝H ₂X ₂+N ₂+I ₂，

Wherein, channel response value is that the reference symbol signal of H1 and H2, corresponding transmitting terminal is that X1 and X2, corresponding interference signal are that I1 and I2, corresponding noise signal are N1 and N2;

Described channel response value H1 and H2 obtain according to following formula:

$\frac{Y_1}{X_1}=H_1+\frac{N_1+I_1}{X_1},$ $\frac{Y_2}{X_2}=H_2+\frac{N_2+I_2}{X_2};$

B, calculate the signal power of corresponding reference symbol resource unit group according to described channel response value, concrete, the signal power on described P1 and P2 is calculated according to following formula and is obtained:

$E[(Y_1/X_1)\·{(Y_2/X_2)}^{*}]=$

$E\left[H_1{H}_2^{*}\right]+E[H_1\·{\left(\frac{N_2+I_2}{X_2}\right)}^{*}]+E[H_2^{*}\·\left(\frac{N_1+I_1}{X_1}\right)]+E[\left(\frac{N_1+I_1}{X_1}\right)\·{\left(\frac{N_2+I_2}{X_2}\right)}^{*}];$

C, reference symbol resource unit group gross power corresponding to the described channel response value of measurement, the gross power of all Resource Unit respective signal responses in described a plurality of resource unit group that measuring and calculating is obtained, deduct the signal power sum of described a plurality of resource unit group, obtain interference plus noise power sum corresponding in described a plurality of resource unit group;

D, obtain the carrier-in-interference noise ratio by the ratio calculation of the interference plus noise power sum of the signal power sum of a plurality of reference symbol resource unit group and a plurality of reference symbol resource unit group, obtain the carrier-in-interference noise ratio according to following formula:

$\widehat{\mathrm{CINR}}=\frac{|\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}(Y_1\left(k\right)/X_1\left(k\right))\·{(Y_2\left(k\right)/X_2\left(k\right))}^{*}|\·2}{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{|Y\left(k\right)/X\left(k\right)|}^2-|\underset{m=1}{\overset{K/2}{\mathrm{\Σ}}}(Y_1\left(k\right)/X_1\left(k\right))\·{(Y_2\left(k\right)/X_2\left(k\right))}^{*}|\·2},$

Wherein, Be carrier-in-interference noise ratio, Y ₁(k) and Y ₂(k) be the reference symbol signal of receiving terminal on two reference symbols on same OFDM symbol in a plurality of Resource Block, the reference symbol signal of corresponding transmitting terminal is X ₁(k) and X2 (k), Y (k)/X (k) is the gross power of each reference symbol resource unit group in a plurality of Resource Block, m=1 to K/2, k=1 to K, K＞0 and be integer.

2. method according to claim 1, is characterized in that, described steps A also comprises:

As described N ₁+ I ₁, N ₂+ I ₂During for the Gaussian random variable of zero-mean, P ₁And P ₂Channel response value H after approximate processing ₁And H ₂Obtain according to following formula:

$H_1\≈\frac{Y_1}{X_1},$ $H_2\≈\frac{Y_2}{X_2}.$

3. method according to claim 1, is characterized in that, described step B also comprises:

Described N ₁+ I ₁, N ₂+ I ₂Be the Gaussian random variable of zero-mean, and described channel response value H ₁And H ₂Value when identical, P ₁And P ₂Signal power after approximate processing obtains according to following formula:

E[(Y ₁/X ₁)·(Y ₂/X ₂) ^*]＝E[|H ₁| ²]。

Images