CN101102133B - Information feedback method - Google Patents

Abstract

The invention is concerned with the information feedback method for applying in communication system. The steps are: A. the receiver collects the feed back; B. the receiver encodes the feedback to signal and transmits the information under fixed vector with special sub-carrier wave; C. the receiver returns the feed back to the sender; D. the sender conducts channel estimation with the fixed vector, and conducts channel repairing to the received signal according to the result of the channel estimation, and estimates the feedback with the received signal that calculate through channel repairing.

Description

A kind of method of feedback information

Technical field

The present invention relates to information feedback technology, particularly a kind of method of feedback information.

Background technology

In the last few years, be the extensive concern that the multi-transceiver technology of representative has been subjected to people with OFDM (OFDM).OFDM (OFDMA) is the new generation of wireless access technology that is modulated to the basis with OFDM, is a kind of new multi-address method of second generation wireless access, and it will insert and modulate effectively and combine.

Along with the continuous development and perfection of OFDMA system, various enhancement techniques as: automatically modulation control (AMC), smart antenna (AAS), multiple-input, multiple-output (MIMO), mix and retransmit (HARQ) etc., being adopted gradually by the OFDMA system.The utilization of these enhancement techniques usually need be at receiving terminal to the transmitting terminal feedback information, as measured value, the Data Receiving success or not of channel quality.These feedback informations will be used for the adjustment of transmission policy, as the selection of code modulation mode, data retransmission whether, directly influence the transmission performance of system, therefore how feed back the problem into a key reliably.

Feedback information tends to be subjected to the interference of several factors in transmission course, such as noise, multipath fading, large scale decline, shadow fading.Feedback information is encoded into one group of orthogonal vectors as transmitting, can strengthens the antijamming capability of feedback information in transmission course, therefore in the system of reality, used widely.

For example, establish α ₁α ₂α _nBe the non-vanishing vector of one group of pairwise orthogonal of Euclidean space V, then have:

${{\mathrm{\α}}_i}^H\·{\mathrm{\α}}_j=\left\{\begin{array}{cc}0& i\≠j\\ {\left|{\mathrm{\α}}_i\right|}^2& i=j\end{array}\right.$

Be example now, illustrate that receiving terminal adopts following orthogonal vectors table to the detailed process of transmitting terminal feedback information in the prior art with the up PUSC pattern of 802.16e.

Wherein, P0, P1, P2, P3 adopt the QPSK modulation system:

$\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}0=\exp (j\&CenterDot;\frac{\mathrm{\&pi;}}{4})$ $\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}1=\exp (j\&CenterDot;\frac{3\mathrm{\&pi;}}{4})$

$\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}2=\exp (-j\&CenterDot;\frac{3\mathrm{\&pi;}}{4})$ $P3=\exp (-j\&CenterDot;\frac{\mathrm{\&pi;}}{4})$

Because in the OFDMA system, Radio Resource is divided into the two-dimensional plane of " time " and " frequency "." time " one dimension is divided into symbol, is 5ms as each symbol duration of Fig. 1, and " frequency " one dimension is divided into subcarrier, is 10kHz as the spacing of each subcarrier among Fig. 1.Like this, the least unit that can be used to transmit is exactly a temporal frequency resource, as the circle among Fig. 1.Arrow among the figure is represented the direction that frequency increases.

Under row mode on the PUSC, the structure of feedback channel as shown in Figure 1, Fig. 1 is the fraction of the two dimensional surface of express time frequency, wherein 4 of mark M subcarriers are as the subcarrier of feedback channel, the transmission orthogonal vectors, subcarrier M0, M1, M2, M3 are exactly available least resource, the temporal frequency resource that does not mark other circular representative of M can be used for transmitting data or orthogonal vectors, but the number that is used to transmit the subcarrier of orthogonal vectors does not influence thought of the present invention, so following all to transmit orthogonal vectors with four subcarriers be that example illustrates.

For example: use the vector 3 in the structure feedback form 1 of feedback channel as shown in Figure 1, so the actual transmissions situation of this feedback channel as shown in Figure 2, promptly four subcarrier M0, M1, M2, M3 that are used for transmitting feedback information transmit P1, P0, P3, P2 respectively.

When detecting feedback information, by each vectorial related operation in received signal and the local vector table, select a vector of degree of correlation maximum, and then estimate the feedback information of emission.With table 1 is example, and four Orthogonal Vectors are arranged, the corresponding feedback information of each Vector Groups, and numbering is followed successively by 0,1,2,3, and the feedback information of different numberings can be represented different implications, such as the measured value of channel quality, the Data Receiving success or not.The signal of supposing M0, Ml, the last reception of M2, M3 for (D0, D1, D2, D3).

Vector index	M0 M1 M2 M3
		0	P0，P0，P0，P0
1	P0，P2，P0，P2

[0016]

2	P0，P1，P2，P3
		3	P1，P0，P3，P2

Table 1 orthogonal vectors table

Then first vector in received signal and the local vector table (P0, P0, P0, it is as follows P0) to carry out the process of related operation:

C0＝||D0 ^*·P0+D1 ^*·P0+D2 ^*·P0+D3 ^*·P0||

Wherein, C0 is the degree of correlation of first orthogonal vectors in the received signal that calculates and the local vector table, D0 ^*Conjugation for D0.

And the like

C1＝||D0 ^*·P0+D1 ^*·P2+D2 ^*·P0+D3 ^*·P2||

C2＝||D0 ^*·P0+D1 ^*·P1+D2 ^*·P2+D3 ^*·P3||

C3＝||D0 ^*·P1+D1 ^*·P0+D2 ^*·P3+D3 ^*·P2||

C0 relatively then, C1, C2, the size of C3, if the C0 maximum, then think received signal with (P0, P0, P0, correlation P0) is the strongest, judges that the feedback information that sends is 0, and then obtains being numbered the feedack that 0 feedback information is represented.

As seen, in the prior art, do not have fixing pilot tone during the feedback channel feedback information, promptly can not carry out channel estimating; And owing to can not carry out channel estimating, can't utilize channel information, thereby the factor that can't consider channel is handled to received signal, directly primary signal and the local vector that receives is carried out relevant treatment, estimates the feedback information error probability height that receives.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of method of feedback information, for channel estimating provides fixing reference data, and uses the result of channel estimating to estimate feedback information more accurately.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of method of feedback information is applied to communication system, it is characterized in that, the method includes the steps of:

A, receiving terminal are collected feedback information;

B, receiving terminal are encoded into feedback information and transmit, and use the subcarrier feedback information, and with specific subcarrier transmit transmit in fixing vector;

C, receiving terminal return feedback information to transmitting terminal;

D, transmitting terminal carry out channel estimating with the fixed vector that transmits on the specific subcarrier, result according to channel estimating carries out channel compensation to the received signal, and the received signal that channel compensation is calculated and each vector in the local vector table carry out related operation, selects the vector of degree of correlation maximum to estimate the feedback information of emission.

Wherein, the sub-carrier number that is used for feedback information described in the step B is 4,6,8 or 12.

The specific subcarrier number of the described transmission fixed vector of step B is 1 or 2.

Feedback information is encoded into described in the step B transmits and adopts QPSK modulation or OFDM modulation that feedback information is encoded into orthogonal vectors to launch again.

Orthogonal vectors described in the step B are arranged in an orthogonal vectors table, be used for transmitting vector of each subcarrier correspondence table of feedback information, the specific subcarrier that is used for transmitting fixed vector is adjusted by adjusting the position of orthogonal vectors in table in the position of orthogonal vectors table.

Wherein, n+1 position adjusted in the position of feeding back n subcarrier of fixed vector, only the vector of n the fixing feedback of subcarrier in the orthogonal vectors table is adjusted to n+1 position, move a position after the vectorial sequential loop of feeding back on the subcarrier with other simultaneously.

The method of carrying out channel estimating described in the step D is: the signal that receives on the specific subcarrier with the transmission fixed component is divided by the fixed component that transmits on this subcarrier.

Described communication system comprises the reponse system that adopts orthogonal vectors.

The reponse system of described employing orthogonal vectors is based on the OFDM communication system for modulation.

Described is 802.16e system and 802.11 systems based on the OFDM communication system for modulation.

This shows, the method of feedback information provided by the present invention, the specific data of subcarrier feedback by fixing ad-hoc location, for channel estimating provides fixing reference value, thereby when estimating feedback information, can consider the factor of channel according to the result of channel estimating, estimate feedback information more accurately, thereby strengthened the reliability of Channel Detection.

Description of drawings

Fig. 1 is the structure of the up PUSC pattern of 802.16e feedback channel in the prior art;

Fig. 2 is the actual transmissions situation in the 802.16e pattern feedback channel in the prior art;

Fig. 3 is that the present invention is at the realization flow figure of feedback channel about feedback method embodiment;

Fig. 4 is the situation of shining upon fixed value P0 in the specific embodiments of the invention one in subcarrier M0;

Fig. 5 is for calculating the method flow diagram of feedback information among the present invention.

Embodiment

The present invention is further described in more detail below in conjunction with drawings and the specific embodiments.

Basic ideas of the present invention are: when adopting the orthogonal vectors feedback information, vector in the vector table when guaranteeing orthogonality relation, is equipped with fixing vector in certain bits, for channel estimating provides fixing reference data, utilize the result of channel estimating to estimate feedback information more accurately.

The method of feedback information disclosed by the invention is mainly used in feedback channel, uses but be not limited only to feedback channel, and when also being used to transmit a spot of data or control information, such as: feedback acknowledgment information, channel measurement information etc.Under different purposes, the process that transmission receives does not change, and just to the explanation difference of information, the content of representing as the vector index in the table 10,1,2,3 can change, to adapt to the needs of different transmission purposes.If 0,1,2,3 four values are not enough to express feedack, can expand span by once sending a plurality of vectors.

It should be noted that, for in feedback information, for channel estimating provides the fixed reference data, in the feedback channel that adopts orthogonal vectors, the position of feedback fix information can be more than one in the vector table, situation as following table table two, only with two orthogonal vectors, the information that can allow two position feedback of M0, M2 fix, can more help channel estimating like this, but compare with the situation that can transmit four feedback informations in the table one during a fixed-site, table two can only transmit two feedback informations, and the amount of information of Chuan Songing has reduced each time.

Vector index	M0 M1 M2 M3
		0	P0，P0，P0，P0
1	P0，P2，P0，P2

[0054]Table 2 is fixed the orthogonal vectors table of two positions

Preferable, under the condition of the number that does not reduce orthogonal vectors, the fixing numerical value of a position in the orthogonal vectors table, can transmit the more information amount, reach goal of the invention simultaneously, be channel estimating the fixed reference data are provided, and use the result of channel estimating to estimate the receiving terminal feedack more accurately.The embodiment that introduces this method below is all being applied to feedback channel, and only to fix an ad-hoc location feedback fixed data be that example illustrates.

Based on above invention thought, the method embodiment that the present invention utilizes the orthogonal vectors feedback information may further comprise the steps as shown in Figure 3:

Step 301: receiving terminal is collected needs feedack;

Step 302: receiving terminal will need feedack to be encoded into orthogonal vectors as transmitting, and use the subcarrier feedback information, and there will be fixing feedback information a position in feedback channel.

Fixedly the position of feedback information can be more than one, but in the increase orthogonal vectors fixedly the position of feedback information need reduce the number of orthogonal vectors, though can help channel estimating more, thereby make that the feedback information of estimating is more accurate, the amount of information of Chuan Songing has reduced each time.Generally, under the condition of the number that does not reduce orthogonal vectors, the numerical value of fixing a position is just passable.

Step 303: receiving terminal sends feedback information.

Step 304: the fixing feedback information of transmitting terminal utilization carries out channel estimating, and make channel compensation to the received signal according to the result of channel estimating, by carrying out related operation through the received signal that calculates behind the channel compensation and each vector in the local vector table, select a vector of degree of correlation maximum, and then estimate the feedback information of emission.

The process of specifically carrying out correlation computations can be referring to following specific embodiment.

Introduce second embodiment below in conjunction with accompanying drawing, the orthogonal vectors table that will be used for feedback information is revised as following table 3:

Vector index	M0 M1 M2 M3
		0	P0，P0，P0，P0
1	P0，P2，P0，P2

[0065]

2	P0，P1，P2，P3
		3	P0，P3，P2，P 1

The orthogonal vectors table that table 3 is new

Order:

$V=\left[\begin{array}{cccc}{P}_0& P_0& P_0& P_0\\ P_0& P_2& P_0& P_2\\ P_0& P_1& P_2& P_3\\ P_0& P_3& P_2& {\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\end{array}\right],$

Then

$V^H=\left[\begin{array}{cccc}{{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}\\ {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}^{*}& {{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}^{*}& {P_3}^{*}\\ {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}^{*}& {{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}^{*}\\ {{\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_0}^{*}& {{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}^{*}& {P_3}^{*}& {{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}^{*}\end{array}\right]$

Have:

${\mathrm{VV}}^H=\left[\begin{array}{cccc}4& 0& 0& 0\\ 0& 4& 0& 0\\ 0& 0& 4& 0\\ 0& 0& 0& 4\end{array}\right]$

Be that each vector in the vector table is keeping orthogonality.

After adopting new orthogonal vectors table, vectorial arbitrarily in the feedback vector table, all will feed back fixing signal P0 in the M0 position.As shown in Figure 4, M0 fixed-site mapping P0.Can utilize the received signal of M0 position and known fixedly information source P0 like this, channel is estimated.

Introduce the reason that can use M0 recited above and P0 that channel is estimated below, suppose that received signal is R in a feedback channel, the signal of transmission is S, and Gaussian noise is N, has

R＝H·S+N

H wherein is the estimation object that carries out channel estimating, supposes that the estimated value that will obtain channel H is

Estimate LS method, estimation according to maximum likelihood Make error

Minimum

$\left|\right|\hat{H}S-R\left|\right|={(\hat{H}S-R)}^H(\hat{H}S-R)$

Order: $\frac{\&PartialD;{(\hat{H}S-R)}^H(\hat{H}S-R)}{\&PartialD;{\hat{H}}^H}=0$

Can obtain by the derivation of equation: $\hat{H}S=R$

On P0, be exactly H0=R0/P0

Suppose still to use in this embodiment M0 shown in Figure 1, M1, four subcarriers of M2, M3 to send feedback information, suppose that the signal that M0, M1, M2, M3 place receive is respectively: (R0, R1, R2, R3), then the step of Chu Liing is specifically as shown in Figure 5:

Step 501: at first carry out channel estimating according to the signal that receives, channel estimation value can be calculated divided by fixing feedback signal by the signal that receives on the subcarrier with the feedback fixed numbers:

Channel estimation value such as the M0 place is expressed as H0, and then H0 can be expressed as:

H0＝R0/P0

Wherein P0 is a fixedly feedack of subcarrier M0, and R0 is the information that receives on the M0;

Under the low speed mobile condition, the channel coefficients of four sub-intercarriers changes very little, so the channel estimating at M1, M2, M3 place can directly be used the channel estimation value H0 at M0 place;

Step 502: feedback information is in the process that transmits, because extraneous interference, the distortion of signal possibility, therefore also need carry out channel compensation, after utilizing the result of the channel estimating that step 501 obtains to carry out channel compensation to the received signal, the received signal that calculates is represented with D0, D1, D2, D3 respectively, because the channel estimating at M1, M2, M3 place can directly be used H0, then

D0＝R0/H0＝P0 D1＝R1/H0

D2＝R2/H0 D3＝R3/H0

Step 503: carry out related operation with what step 502 calculated through signal behind the channel compensation and the orthogonal vectors in the local vector table, detailed process is:

C0＝||D0 ^*·P0+D1 ^*·P0+D2 ^*·P0+D3 ^*·P0||

C1＝||D0 ^*·P0+D1 ^*·P2+D2 ^*·P0+D3 ^*·P2||

C2＝||D0 ^*·P0+D1 ^*·P1+D2 ^*·P2+D3 ^*·P3||

C3＝||D0 ^*·P0+D1 ^*·P3+D2 ^*·P2+D3 ^*·P1||

Step 504: select a vector of degree of correlation maximum in the local vector table, and then estimate the feedback information of emission:

Promptly compare C0, C1, C2, the size of C3 is if the C0 maximum judges that then feedback information is 0.If the C1 maximum judges that then feedback information is 1, and the like, the measured value of channel quality, information such as Data Receiving success or not obtained according to the feedback information representative of difference numbering about the concrete implication of feedback channel then.

Not being both of the 3rd embodiment and second embodiment changes the M0 position among Fig. 4 the ad-hoc location of M1 position as the feedback fixed data into, promptly the position of the specific subcarrier of feedback fixed data can be adjusted in the orthogonal vectors table, the method of adjusting to orthogonal vectors table table 4 from orthogonal vectors table table 3 is, be numbered 2 orthogonal vectors (P0 with vector index, P1, P2, P3) be example, the signal P0 that the M0 place of feedback fixed numbers is fed back moves on to the subcarrier M1 place of feeding back fixed numbers behind the conversion orthogonal vectors table, and with original M1, M2, the signal of M3 place feedback moves a subcarrier successively backward, orthogonal vectors after shifting one's position are (P3, P0, P1, P2), all the other are numbered 0,1, and 3 orthogonal vectors are also carried out above-mentioned conversion, described in the orthogonal vectors table such as table 4 after the conversion, position in the orthogonal vectors table of feedback fixed numbers also can be M2 or M3, when the fixed position is M1, as long as adjust orthogonal vectors table such as table 4:

Vector index	M0 M1 M2 M3
		0	P0，P0，P0，P0
1	P2，P0，P2，P0
		2	P3，P0，P1，P2
3	P1，P0，P3，P2

Table 4 interchangeable orthogonal vectors table

Suppose that four subcarriers that are used to send feedback information are respectively M0, M1, M2, M3, the signal that correspondence is received is respectively (R0, R1, R2, R3), and when the step 501 of then corresponding embodiment three was carried out channel estimating, the channel estimation value of establishing the M1 place was H1, then

H1＝R1/P0，

Wherein, the information that receives on the subcarrier M1 of R1 for the feedback fix information, P0 goes up fixedly feedack for subcarrier M1;

Accordingly, the channel estimating at M0, M2, M3 place can directly be represented with H1.

When the step 502 of corresponding embodiment three was carried out channel compensation, the signal that each subcarrier receives was represented with D0, D1, D2, D3 respectively through behind the channel compensation, because the channel estimating at M0, M2, M3 place can directly be used H1, then

D0＝R0/H1 D1＝R1/H1＝P0

D2＝R2/H1 D3＝R3/H1

D0, D1, D2, D3 are got in the formula of substitution step 503 correspondence after the conjugation, computational methods are identical with step 503 and step 504 among the embodiment three.

Introduce the 4th embodiment below, in embodiment two, because P0, P1, P2, P3 adopt the QPSK modulation, the numeric field channel that is P0, P1, P2, P3 correspondence is respectively: " 00 " " 10 " " 11 " " 01 ", if the vector in the orthogonal vectors table is represented at data field, is obtained following table:

Vector index	M0 M1 M2 M3
		0	00，00，00，00
1	00，11，00，11
		2	00，10，11，01
3	00，01，11，10

Table 5 orthogonal vectors table is in the expression of numeric field

Learn that easily the orthogonal vectors that numeric field is represented still keep orthogonality relation.Therefore, utilizing channel estimating that the detection of orthogonal vectors is put into numeric field carries out, still pass through the degree of correlation of the vector in channel estimating, channel compensation, calculating received signal and the local vector table, an and vector of selection degree of correlation maximum, thereby estimate the feedback information of emission, owing to considered the factor of channel, thereby estimated that the feedback information of emission can be more accurate.

The foregoing description two, three and four all is only to adopt four subcarriers to come feedback information in feedback channel, main thought of the present invention is to remain on fixedly feedback data of certain location, so that carry out channel estimating, thereby utilize the result of channel estimating can estimate the receiving terminal feedack more accurately.Method based on the feedback information of above thought can be estimated feedback information more accurately, thereby improve the detection performance of feedback channel, so can in feedback channel, adopt more subcarrier, such as adopting six, eight or 12 subcarriers, as long as the orthogonal vectors table that meets the demands is arranged.

In addition, performance and raising capacity for enhanced system can adopt multi-antenna technology and repeated encoding technology usually, but all need to use channel estimating in these two kinds of technology.During such as the employing multi-antenna technology, the processing method commonly used at receiving terminal is " merging ", and " channel estimating " in the processing procedure is necessary." high specific merging " method with two reception antennas is an example, suppose what feedback information that reception antenna 0 is received was still with M0 shown in Figure 1, M1, four subcarriers feedbacks of M2, M3, M0 is feedback information P0 fixedly, and the signal that receives on M0, M1, four subcarriers of M2, M3 is respectively (R0, R1, R2, R3), then the channel estimating to subcarrier M0 is H0=R0/P0, the channel estimating at M1, M2, M3 place also can be represented with H0, the channel vector h of reception antenna 1 described below ₁=H0.The channel vector h of reception antenna 1 ₂Also can use the same method and calculate.Suppose:

The channel vector h of reception antenna 0 ₁, received signal is y ₁, noise is n ₁

The channel vector h of reception antenna 1 ₂, received signal is y ₂, noise is n ₂

The formula that then two reception antennas is carried out the high specific merging is:

$s=\frac{{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">h</figure-callout>}}_1^{*}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">y</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">h</figure-callout>}}_2^{*}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">y</figure-callout>}}_2}{{\left|{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">h</figure-callout>}}_1\right|}^2+{\left|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="H06198426020060713E000011.png,H06198426020060713E000012.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\right|}^2}$

The received signal expression formula is:

y ₁＝h ₁·s+n ₁

y ₂＝h ₂·s+n ₂

Can see that " channel vector " that obtain by " channel estimating " is indispensable when the signal that multiaerial system is received carries out the signal merging.

In addition, sometimes for fear of information dropout, same content can be transmitted twice, at this moment can use the repeated encoding technology, if there is not channel estimating, the identical information that receiving terminal can repeat twice of receiving to transmit is regarded independent information as, can't carry out the merging of information, thereby does not reach the performance gain that the repeated encoding technology should be brought to system.The same with the multi-antenna technology of introducing above, the repeated encoding technology also needs to utilize the result of channel estimating that the signal that receives is merged.

This shows, when adopting method feedback information of the present invention, can carry out channel estimating; And having under the condition of channel estimating, can adopt multi-antenna technology and repeated encoding technology to wait and strengthen the detection performance.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 (10)

1. the method for a feedback information is applied to communication system, it is characterized in that, the method includes the steps of:

A, receiving terminal are collected feedback information;

B, receiving terminal are encoded into feedback information and transmit, and use the subcarrier feedback information, and transmit fixing vector with specific subcarrier;

C, receiving terminal return feedback information to transmitting terminal;

D, transmitting terminal carry out channel estimating with the fixed vector that transmits on the specific subcarrier, result according to channel estimating carries out channel compensation to the received signal, and the received signal that channel compensation is calculated and each vector in the local vector table carry out related operation, selects the vector of degree of correlation maximum to estimate the feedback information of emission.

2. method according to claim 1 is characterized in that, the sub-carrier number that is used for feedback information described in the step B is 4,6,8 or 12.

3. method according to claim 1 and 2 is characterized in that, the specific subcarrier number of the described transmission fixed vector of step B is 1 or 2.

4. method according to claim 1 is characterized in that, the method that transmits that feedback information is encoded into described in the step B is: adopt QPSK modulation or OFDM modulation that feedback information is encoded into orthogonal vectors.

5. method according to claim 4, it is characterized in that, orthogonal vectors described in the step B are arranged in an orthogonal vectors table, and vector in each subcarrier correspondence table of transmission feedback information is by adjusting the specific subcarrier that the position adjustment of orthogonal vectors in table transmits fixed vector.

6. method according to claim 5, it is characterized in that, described method of adjustment is: n+1 position adjusted in the position that will feed back n subcarrier of fixed vector, only the vector of n the fixing feedback of subcarrier in the orthogonal vectors table is adjusted to n+1 position, move a position after the vectorial sequential loop of feeding back on the subcarrier with other simultaneously.

7. method according to claim 1 is characterized in that, the method for carrying out channel estimating described in the step D is: the signal that receives on the specific subcarrier with the transmission fixed component is divided by the fixed component that transmits on this subcarrier.

8. method according to claim 1 is characterized in that described communication system comprises the reponse system that adopts orthogonal vectors.

9. method according to claim 8 is characterized in that the reponse system of described employing orthogonal vectors is based on the OFDM communication system for modulation.

10. method according to claim 9 is characterized in that, described is 802.16e system and 802.11 systems based on the OFDM communication system for modulation.

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