WO2012068865A1

WO2012068865A1 - Channel estimation method and system in broadband co-frequency interference environment

Info

Publication number: WO2012068865A1
Application number: PCT/CN2011/075457
Authority: WO
Inventors: 朱登魁; 肖华华; 宁迪浩; 鲁照华
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-11-23
Filing date: 2011-06-08
Publication date: 2012-05-31
Also published as: CN102480440A; CN102480440B

Abstract

The invention discloses a channel estimation method and system in broadband co-frequency interference environment, which are applied to the receivers in orthogonal frequency division multiplexing (OFDM) systems or orthogonal frequency division multiple access (OFDMA) systems. In an interference suppression area, when the channel estimation is performed for one of carried data streams, the method includes: for each pilot subcarrier corresponding to the data stream, the received signal on the pilot subcarrier is multiplied by the conjugate of the pilot signal transmitted by the transmitter on the pilot subcarrier to obtain the channel-coefficient estimation value of the pilot subcarrier; for each data subcarrier corresponding to the data stream, the weighed average of each channel-coefficient estimation value on the pilot subcarrier corresponding to the data stream is regarded as the channel-coefficient estimation value on the data subcarrier; the interference suppression area is a time-frequency two-dimension resource block in the carrier area of the received data. With the invention, the accurate channel estimation can be performed when broadband co-frequency interference exists between the adjacent cells.

Description

Channel estimation method and system in broadband co-channel interference environment

Technical field

The present invention relates to an OFDM (Orthogonal Frequency Division Multiplexing)/OFDMA (Orthogonal Frequency Division Multiple Access) system, and specifically relates to overcoming broadband equal frequency in an OFDM/OFDMA system. Interfering channel estimation method and system.

Background technique

Multi-antenna technology is a major breakthrough in smart antenna technology in the field of wireless mobile communications. This technology can multiply the capacity and spectrum utilization of communication systems without increasing bandwidth. It can also use multipath to mitigate multipath fading. It can effectively eliminate channel interference, improve channel reliability, and reduce bit error rate. It is a key technology used in next-generation mobile communication systems. It has been widely used in a variety of wireless broadband systems such as LTE (Long Term Evolution) and WiMAX (World Interoperability for Microwave Access).

For a wireless communication system in which a network is arranged in a cellular structure, co-channel interference between adjacent cells is one of the most important factors leading to a decline in communication quality, as shown in FIG. Because the interference source is a data signal sent by the neighboring cell user on the same time-frequency resource, the receiver must be able to accurately estimate the channel coefficient, the interference channel coefficient or the interference feature of the desired data to be more accurate. Data detection, but when the data subcarriers and pilot subcarriers between adjacent cells coincide at the time-frequency position, it will bring great difficulty to the interference estimation, because the coincidence of the interference pilots will lead to the degradation of the channel estimation quality. That is, the channel estimation itself carries the interference information, so that the interference noise feature estimation becomes very difficult or very inaccurate. In this case, the performance of common interference suppression receiving algorithms, such as MMSE (Minimum Mean Square Error) or Interference Rejection Combination (IRC) algorithm, will be greatly reduced. Summary of the invention The object of the present invention is to provide a channel estimation method and system in a wideband co-channel interference environment to solve the problem of inaccurate channel estimation when there is broadband co-channel interference in a neighboring cell.

To solve the above problem, the present invention provides a channel estimation method in a wideband co-channel interference environment, which is applied to a receiving end of an Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) system, In the interference suppression area, when performing channel estimation on a data stream carried therein, the method includes:

Multiplying the received signal on the pilot subcarrier with the conjugate of the pilot signal transmitted by the transmitting end on the pilot subcarrier to obtain the pilot subcarrier for each pilot subcarrier corresponding to the data stream. Estimated channel coefficient for the location;

For each data subcarrier corresponding to the data stream, a weighted average of channel coefficient estimates of the pilot subcarrier positions corresponding to the data stream is used as an estimated channel coefficient of the data subcarrier position; wherein the interference suppression The area is a time-frequency two-dimensional resource block in the received data bearer area. Optionally, the above method may also have the following features:

For each data subcarrier corresponding to the data stream, the weighted average of the channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream is used as a step of estimating the channel coefficient of the data subcarrier position. The formula is as follows:

The channel coefficient estimation value of the jth data subcarrier position corresponding to the data stream in the interference suppression area, j = \ , J , J is the number of data subcarriers corresponding to the data stream in the interference suppression area ; %. To calculate the channel coefficient estimate for the jth data subcarrier position, assign the weight of ^ ( ), ∑α, = ΐ ; ^ (0 is the first corresponding to the data stream in the interference suppression region The channel coefficient estimated value of the pilot subcarrier position, = 1, ···, /, / is the number of pilot subcarriers corresponding to the data stream in the interference suppression region. Optionally, the foregoing method may further include:

Before calculating the channel coefficient estimation value of the data subcarrier position according to the formula (a), the interference suppression region is divided into one or more channel estimation units, and each channel sound estimation unit is a time domain two-dimensional resource. Block and including at least one pilot subcarrier and one data subcarrier;

When calculating the channel coefficient estimate of the data subcarrier position according to equation (a), use one or more of the following constraints:

Constraint 1, when calculating the channel coefficient estimation value of a data subcarrier position, assigning the same weight to the channel coefficient estimation value of each pilot subcarrier position in the same channel estimation unit;

Constraint two, when calculating the channel coefficient estimates for each data subcarrier position in the same channel estimation unit, all set the same weight = 1,···, /, j = l, ', J. Optionally, the above method may also have the following features:

The interference suppression area is divided into f channel estimation units, each channel sound estimation unit is a time domain two-dimensional resource block and includes at least one pilot subcarrier and one data subcarrier, where K is a positive integer;

For each data subcarrier corresponding to the data stream, the weighted average of the channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream is used as the calculation of the channel coefficient estimation value of the data subcarrier position. The formula is as follows:

Where h _d ^k is an estimated channel coefficient of each data subcarrier position corresponding to the data stream in the A channel estimation unit, k = \, 2, --, K

/ is a loop variable, 1 = 1, 2, ···,Κ

a set of index I of pilot subcarriers corresponding to the data stream included in the channel estimation unit, = 1,···, /, / is the number of pilot subcarriers corresponding to the data stream; ( ) is an estimated channel coefficient of the first pilot subcarrier position corresponding to the data stream in the interference suppression region;

When O _kl is calculated, the weight of ^ (/) of each pilot subcarrier position in the channel estimation unit is given,

| | indicates the number of pilot subcarrier indices included.

1=1 Optionally, the above method may also have the following features:

Calculate the weight of 3⁄4釆 according to formula (b), where 3 = 4, 1 = \, 2, ---, K, greater than or equal to other weights. Optionally, the above method may also have the following features:

Transmitting the received signal on the pilot subcarrier with the conjugate of the pilot signal sent by the transmitting end on the pilot subcarrier to obtain the pilot for each pilot subcarrier corresponding to the data stream In the step of estimating the channel coefficient of the subcarrier position, the calculation formula is as follows: P(i) = y _p (i)p*(i) (c)

The channel coefficient estimated value of the first pilot subcarrier position corresponding to the data stream in the interference suppression area is a received signal on the first pilot subcarrier, where is the transmitting end. a pilot signal transmitted on the first pilot subcarrier, (0 indicates that the conjugate is conjugated, ί = 1,···, Ι, / is the pilot subcarrier corresponding to the data stream in the interference suppression region Correspondingly, the present invention also provides a channel estimation system in a wideband co-channel interference environment, which is used for a receiving end of an Orthogonal Frequency Division Multiplexing (OFDM) or an Orthogonal Frequency Division Multiple Access (OFDMA) system. Channel estimation is performed on a data stream carried in an interference suppression area, where the interference suppression area is a time-frequency two-dimensional resource block in the received data bearer area, and the system includes:

a first device, configured to: conjugate phase of the received signal on the pilot subcarrier and the pilot signal sent by the transmitting end on the pilot subcarrier for each pilot subcarrier corresponding to the data stream Multiplying, to obtain an estimate of the channel coefficient of the pilot subcarrier position;

a second device, configured to: perform weighted averaging of channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream for each data subcarrier corresponding to the data stream, as a channel coefficient of the data subcarrier position estimated value. Optionally, the above channel estimation system may also have the following features:

The second device is configured to use, as a calculation method, a weighted average of channel coefficient estimates of the pilot subcarrier positions corresponding to the data stream for each data subcarrier corresponding to the data stream, as the data sub Estimated channel coefficient of the carrier position:

I

Hd(j) = _ij h _p (i) ( _3⁄4 )

i=l The channel coefficient estimation value of the Jth data subcarrier position corresponding to the data stream in the interference suppression area, j = \ , J , J is the number of data subcarriers corresponding to the data stream in the interference suppression area ; "To calculate the channel coefficient estimate of the _; data subcarrier position, give ^ (weight of 0, ∑α, =ΐ; ^ (0 is the first corresponding to the data stream in the interference suppression area) The estimated channel coefficient of the pilot subcarrier position, = 1,···, /, / is the number of pilot subcarriers corresponding to the data stream in the interference suppression region. Optionally, the above channel estimation system may also Has the following characteristics:

The channel estimation system further includes a third device configured to: divide the interference suppression region into one or more channel estimation units, each channel sound estimation unit being a time domain two-dimensional resource block and including at least one pilot therein Subcarrier and one data subcarrier;

Correspondingly, the second means is configured to calculate a channel coefficient estimate of the data subcarrier position according to equation (a) using any one or more of the following constraints:

Constraint two, when calculating the channel coefficient estimates for each data subcarrier position in the same channel estimation unit, all set the same weight = 1,···, /, j = l, ', J. Optionally, the above channel estimation system may also have the following features:

The channel estimation system further includes a third device configured to: divide the interference suppression region into

K channel estimation units, each channel sound estimation unit is a time domain two-dimensional resource block and includes at least one pilot subcarrier and one data subcarrier, and f is a positive integer;

Correspondingly, the second device is configured to use, as a calculation formula, a weighted average of channel coefficient estimates of each pilot subcarrier position corresponding to the data stream for each data subcarrier corresponding to the data stream. Estimated channel coefficient of the data subcarrier position:

/ is a loop variable, 1 = 1, 2, ···,Κ

When O _kl is calculated, the position of each pilot subcarrier in the channel estimation unit is given ^ (/)

K

Weight, ∑Ι ^Ω ′′ ^{= 1} , ^{0 ≤ ≤1} , | | indicates the number of pilot subcarrier indices included, and

1=1

In the weight "3⁄4, 1 = 1, 2, · '·, Κ , " is greater than or equal to other weights _t

Using the above method and system, channel estimation can be accurately performed when there is wideband co-channel interference in neighboring cells, thereby improving the performance of interference suppression and the accuracy of data detection. BRIEF abstract

1 is a schematic diagram of a neighboring multi-cell in the prior art;

2 is a flowchart of a channel estimation method according to an embodiment of the present invention;

3 to FIG. 7 are schematic diagrams showing five ways of dividing the interference suppression region pattern 1 according to an embodiment of the present invention. The bold coil represents the pilot subcarrier, and the thin coil represents the data subcarrier, and FIG. 8 to FIG. 11 are the same;

8 to FIG. 9 are schematic diagrams showing two ways of dividing the interference suppression area pattern 2 according to an embodiment of the present invention;

10 to FIG. 11 are schematic diagrams showing two ways of dividing the interference suppression region pattern three according to an embodiment of the present invention; in the figure, the thick coil represents the pilot subcarrier corresponding to the data stream 1, and the dotted coil represents the data stream 2 corresponding to the data stream 2; Pilot subcarrier, thin coil represents data subcarrier, Figure 13 is the same;

Preferred embodiment of the invention

In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be arbitrarily combined with each other.

The estimation and suppression method for wideband co-channel interference in this embodiment is applied to an OFDM/OFDMA system. The sender of the text can be a control device such as a station or a relay station, or a terminal device such as a mobile phone, a notebook computer, or a handheld computer. Similarly, the receiving end is configured to receive the data signal of the transmitting end, and the receiving end may be a terminal device such as a mobile phone, a notebook computer, a handheld computer, or a control device such as a base station or a relay station.

The receiving end divides the received data bearer area into one or more interference suppression areas, and each interference suppression area is a time-frequency two-dimensional resource block in the frame/field structure, that is, each interference suppression area includes multiple times in time. A continuous OFDM/OFDMA symbol, comprising a plurality of consecutive subcarriers in the frequency domain. The receiving data bearer area may include a time-frequency two-dimensional resource block, and may also include a plurality of separate time-frequency two-dimensional resource blocks. In this embodiment, each of the time-frequency two-dimensional resource blocks is used as an interference suppression area. . Of course, in other embodiments, one time-frequency two-maintenance resource block in the received data bearer area may also be divided into multiple interference suppression areas. In an OFDM/OFDMA system, the interference suppression area may carry one or more data streams, each data stream corresponding to a plurality of data subcarriers and pilot subcarriers, and different pilot streams corresponding to different data streams are different.

As shown in FIG. 2, when performing channel estimation on a data stream carried in the method according to the embodiment in an interference suppression area, the method includes:

Step 10: Multiply, by the pilot signal received on the pilot subcarrier and the conjugate of the pilot signal sent by the transmitting end on the pilot subcarrier, for each pilot subcarrier corresponding to the data stream, Obtaining an estimated channel coefficient of the pilot subcarrier position;

The first pilot subcarrier corresponding to the data stream in the interference suppression region is represented by PsC(z). Estimated channel coefficient of the PsC(i) position h _P (i)

Wherein, the channel coefficient estimation value of the PsC(i) position is a received signal on PsC(z), which is a pilot signal transmitted by the transmitting end on PsC(z), indicating a pair; ^) taking a conjugate, ί = 1,···, Ι , / is the number of pilot subcarriers corresponding to the data stream in the interference suppression region.

Because the cross-correlation of pilot signals on the same pilot subcarrier is relatively low, the interference signal from the pilot band of the adjacent cell on the pilot subcarrier can be filtered out to obtain a more accurate channel coefficient estimation. value.

Step 20: The weighted average of the channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream is used as the channel coefficient estimation value of the data subcarrier position for each data subcarrier corresponding to the data stream;

Denoting the jth data subcarrier corresponding to the data stream in the interference suppression region by using DsC(), _/= V-, J, J is the number of data subcarriers corresponding to the data stream in the interference suppression region, DsCG) Channel coefficient estimate for position / :

Where, (in order to calculate DsCG) position, give ^ (weight of 0, l _y ⁼¹ , the weight of the part can be 0, the meanings of other parameters are as above.

Through the above two steps, the receiving end has completed channel estimation of the pilot subcarrier and the data subcarrier position corresponding to one data stream in one interference suppression region. Different interference suppression regions can be calculated in the above manner. Of course, the specific weight selection can be different.

Since the channel coefficient estimates of the pilot subcarrier positions are relatively accurate, the channel coefficient estimates of the data subcarrier positions obtained by their weighted average are also relatively accurate.

For each interference suppression area included in the received data bearer area, the channel estimation may be performed on each data stream carried by the interference suppression area by using the foregoing method, and the weights may be different.

Before the calculation according to the formula (2), the receiving end may further divide the interference suppression area into K channel estimation units, where each channel estimation unit is a time-frequency domain two-dimensional resource block, and includes at least one The pilot subcarrier and one data subcarrier, and f is a positive integer.

In an embodiment in which the channel estimation unit partitioning is performed, when the channel coefficient estimation value of a certain data subcarrier position is calculated according to the formula (2), the channel coefficient estimation value of each pilot subcarrier position in the same channel estimation unit is given. The weights are the same.

In another embodiment in which the channel estimation unit partitioning is performed, when the channel coefficient estimation values of the respective data subcarrier positions in the same channel estimation unit are calculated according to formula (2), a set of the same weight α, = ν is taken. ··, /, 7 = 1,···, J , that is, the obtained channel coefficient estimation values of the respective data subcarrier positions are the same. In still another embodiment of performing channel estimation unit division, the manner of the above two embodiments may be combined. as follows:

Defining, by the kth channel estimation unit, a set of index subcarriers corresponding to the data stream corresponding to the data stream is k = \, 2, ···, , each data corresponding to the data stream in the channel estimation unit The channel coefficient estimates of the subcarrier positions are equal, and it is recorded that the receiving end calculates the 3⁄4 as follows:

Where / is a cyclic variable, 1 = 1, 2, ..., 3⁄4 is the weight assigned to the estimated channel coefficient of each pilot subcarrier position in the channel estimation unit, because it is a weighted average,

Κ

To satisfy the condition ∑ | , I = 1, 0 ≤ ≤ 1 , where | _q I represents the pilot contained in the pilot index set _q

1=1

The number of subcarrier indices.

It can be seen that, when calculating the channel coefficient estimation value of a certain data subcarrier position according to formula (2), the same weight is obtained for the channel coefficient estimation value of each pilot subcarrier position in the same channel estimation unit. And when calculating the channel coefficient estimation value of each data subcarrier position in the same channel estimation unit, by taking the same set of weight values, the obtained channel coefficient estimation values of the respective data subcarrier positions are the same.

In the time domain region, the closer the pilot subcarriers are to a certain data subcarrier, the stronger the channel correlation. Therefore, preferably, in calculating the weight 3⁄4 used in the formula (3), " _{3⁄4 is} greater than or equal to the other weights, 1 = \, 2, ···, Κ.

The above calculation based on the channel estimation unit can simplify the calculation. Correspondingly, the embodiment further provides a channel estimation system in a broadband equal-frequency interference environment, which is used for receiving ends of an Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) system, Channel estimation is performed on a data stream carried in the interference suppression area, where the interference suppression area is a time-frequency two-dimensional resource block in the received data bearer area, and the system includes:

a first device, configured to: conjugate phase of the received signal on the pilot subcarrier and the pilot signal sent by the transmitting end on the pilot subcarrier for each pilot subcarrier corresponding to the data stream Multiplying, obtaining an estimated channel coefficient of the pilot subcarrier position;

a second device, configured to: perform weighted averaging of channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream for each data subcarrier corresponding to the data stream, as a channel coefficient of the data subcarrier position estimated value.

Preferably,

The second device uses, for each data subcarrier corresponding to the data stream, a weighted average of the channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream, as an estimated channel coefficient of the data subcarrier position, The calculation formula used is as in the above formula (2). Preferably,

The system may further include a third device, configured to: divide the interference suppression region into f channel estimation units, each channel sound estimation unit is a time domain two-dimensional resource block and includes at least one pilot subcarrier and a data subcarrier, f is a positive integer;

Correspondingly, the second device weights the channel coefficient estimation value of each pilot subcarrier position corresponding to the data stream as the channel coefficient of the data subcarrier position for each data subcarrier corresponding to the data stream. The estimated value and the calculation formula used are as shown in the above formula (3). Preferably,

The system further includes a third device configured to: divide the interference suppression region into one or more channel estimation units, each channel sound estimation unit being a time domain two-dimensional resource block and including at least one pilot subcarrier therein And a data subcarrier;

Correspondingly, the second device uses, as the data subcarrier, a weighted average of the estimated channel coefficient values of the pilot subcarrier positions corresponding to the data stream for each data subcarrier corresponding to the data stream. When estimating the channel coefficient of the location, any one or more of the following constraints are used: Constraint 1, when calculating the channel coefficient estimation value of a certain data subcarrier position, is the position of each pilot subcarrier in the same channel estimation unit. The channel coefficient estimates are assigned the same weight;

Constraint 2, when calculating the channel coefficient estimates for each data subcarrier position in the same channel estimation unit, all of them have the same weight = 1, · · ·, /, j = l, ', J.

The invention is further illustrated by some application examples below. In the following examples, the meaning of each parameter is the same as that of the above embodiment. The example mainly explains how to further calculate the channel coefficient estimation value of the data subcarrier in the case of different interference suppression region patterns and channel estimation unit division. It should be noted that in the actual system, it is not limited to the enumerated examples.

Application example one

It contains 15 consecutive OFDM/OFDMA symbols and contains 4 consecutive subcarriers in the frequency domain, which carries one data stream. In this example, the interference suppression region is equally divided into channel estimation units, and the indexes of the 20 pilot subcarriers included in the interference suppression region belong to 5 pilot index sets, that is, 1 to 4 belong to 5-8. 9~12 belongs to ί3⁄4, 13~16 belongs to Ω ₄ , and 17~20 belongs to ί3⁄4. When performing channel estimation:

The channel coefficient estimates on all data subcarriers in the first channel estimation unit are 3⁄4, with: (/')

The estimated channel coefficients on all data subcarriers in the second channel estimation unit are , with:

^ 4 8 12 16 20

3⁄4 = «21 Σ {ή + «22 {ή + «23 (0 + «24

;=1 i=5 i=9 ;=13 (0 ⁺ «25

i Σ=\7 (The estimated channel coefficients on all data subcarriers in the third channel estimation unit are, are: (0

The estimated channel coefficients on all data subcarriers in the fourth channel estimation unit are , with:

^ 4 8 12 16 20

3⁄4 = «41 Σ {ή + «42

;=1 i=5 ( + «43

i=9 (0 + «44

;=13 (0 ⁺ "45

i Σ=l7 (The estimated channel coefficients on all data subcarriers in the fifth channel estimation unit are, with:

Wherein, the condition tlQ| = i , 0<3⁄4 <1 , k = l, --, 5 , | | represents the number of pilot subcarriers included in the pilot index set.

Application Example 2 The interference suppression area in this application example is the interference suppression area pattern one. As shown in FIG. 4, the interference suppression area is divided into three channel estimation units, and the indexes of the 20 pilot subcarriers included in the interference suppression area belong to three pilot index sets, wherein 1~8 belong to, 9~ 16 belongs to 17~20 belongs to ί3⁄4. When performing channel estimation:

The estimated channel coefficients on all data subcarriers in the first channel estimation unit are 3⁄4, with:

^ 8 16 20

3⁄4 = «21 Σ {ή + «22 AW

i=l Σ i=9 (0 + "23 T

i=\7

The estimated channel coefficients on all data subcarriers in the third channel estimation unit are both, with: ^ 8 16 20

i=\7

Where = 1,2,3, | | indicates the pilot index

The number of pilot subcarriers included in the combination.

Application example three

The interference suppression area in this application example is the interference suppression area pattern one. As shown in FIG. 5, the interference suppression region is divided into one channel estimation unit, and the index of the 20 pilot subcarriers included in the interference suppression region belongs to one pilot index set, that is, 1 to 20 belong to . When performing channel estimation:

Estimating the channel coefficients on all data subcarriers in the channel estimation unit is 3⁄4, with:

Wherein, the condition is satisfied: | |«„=i, 0<α _η <1, || represents the number of pilot subcarriers included in the pilot index set.

Application example four

The interference suppression area in this application example is the interference suppression area pattern one. As shown in FIG. 6, the interference suppression area is divided into two channel estimation units, and the pilot indexes 1, 2, 5, 6, 9, 10, 13, 14, 17, 18 included in the interference suppression area belong to the pilot index. The remaining 10 pilot indices of the set belong to the pilot index set ί3⁄4. When performing channel estimation:

The estimated channel coefficient corresponding to the first channel estimation unit is recorded as:

The estimated channel coefficient corresponding to the second channel estimation unit is recorded as: /'e ί3⁄4 /'e Ω2 For any data subcarrier /e Ω inside the above interference suppression area, the estimated channel coefficients are:

Where the condition is met | | =i, 0<3⁄4<1, k = \,2, | | denotes the pilot index set

1=1

The number of pilot included in the pilot _subcarriers, Ά1, a weighting factor, which value can vary as a data subcarrier index / a, Q _d represents the index for all data subcarriers within the region set interference suppression.

In this example, the channel coefficient estimation value of the data subcarrier is calculated. When calculating the channel coefficient estimation value of each data subcarrier in the same channel estimation unit, different weights can be taken to obtain different results. However, for each pilot subcarrier in the same channel estimation unit, the same weight is assigned. In addition, the foregoing calculation manner is also a weighted average of the channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream, and is a specific manner of the channel coefficient estimation value of the data subcarrier position corresponding to the data stream, and may be one step. The calculation is complete.

Application example five

The interference suppression area in this application example is the interference suppression area pattern one. As shown in FIG. 7, the interference suppression region is divided into four channel estimation units, wherein the pilot subcarrier indices 1, 2, 5, and 6 belong to the pilot index set pilot subcarrier index 9, 10, 13, 14, 17, 18 belongs to the pilot index set pilot subcarrier index 3, 4, 7, 8 belongs to the pilot index set ί3⁄4, and the remaining pilot subcarrier index belongs to the pilot index set Ω ₄ . When performing channel estimation:

h _p ( ) The estimated channel coefficient corresponding to the second channel estimation unit is recorded as: = h _p ( )

The estimated channel coefficient corresponding to the third channel estimation unit is recorded as:

The estimated channel coefficient corresponding to the fourth channel estimation unit is recorded as: Κ = _4l ∑ h _p (i) + ₄₂ ∑ h _p (i)

h _p (i) + ₄₄ ∑ h _p (i) ieQ^ ;ΈΩ2 ;Έί3⁄4 ;Έί3⁄4 For any data subcarrier / e Ω inside the interference suppression region, the estimated channel coefficients are:

Where | | represents the pilot index set

The number of pilot subcarriers included, γ _υ and γ ₂ γ ₃ are weighting coefficients, the value of which may vary with /, and Q _d represents the index set of all data subcarriers within the interference suppression region.

Application example six

As shown in FIG. 8, the interference suppression region in this application example is an interference suppression region pattern 2, which includes 12 consecutive OFDM/OFDMA symbols in the time domain, and 4 consecutive subcarriers in the frequency domain, where one is carried. data flow.

In this example, the interference suppression area is equally divided into four channel estimation units, and the indexes of the 16 pilot carriers included in the interference suppression area belong to four pilot index sets, that is, 1~4 belongs to 5~8. 9 to 12 belong to ί3⁄4 and 13 to 16 belong to Ω ₄ . When performing channel estimation: The channel coefficient estimates on all data subcarriers in the first channel estimation unit are all 3⁄4, with:

The estimated channel coefficients on all data subcarriers in the second channel estimation unit are: ^ 4 8 12 16

3⁄4 = «21 ( ⁺ "22∑ (/') + «23∑^ ( + «24∑^

;=1 i=5 i=9 ;=13 (The estimated channel coefficients on all data subcarriers in the third channel estimation unit are:

^ 4 8 12 16

3⁄4 = «41 (/') + «42∑^ (/') + «43∑^ (/') + «44∑^

;=1 i=5 i=9 ;=13 (where satisfies the condition=1, 0<3⁄4 <1 , Λ = 1,···, 4 , | | represents the pilot subcarrier contained in the pilot index set Number.

Application example seven

The interference suppression area in this example is the interference suppression area pattern 2. As shown in FIG. 9, the interference suppression area is divided into two channel estimation units, and the 16 pilots included in the interference suppression area belong to two pilot index sets, wherein 1~8 belong to 9~16 belongs to ί3⁄4. When performing channel estimation:

^ 8 16

;=1 i=9

The estimated channel coefficients on all data subcarriers in the second channel estimation unit are:

Where the condition is met | | =i , 0<3⁄4 <1 , k = \,2, | | represents the set of pilot indices

1=1

The number of pilot subcarriers included in the packet. . Application example eight

It contains 9 consecutive OFDM/OFDMA symbols and contains 4 consecutive subcarriers in the frequency domain, which carries one data stream. In this example, the interference suppression region is equally divided into three channel estimation units, and the indexes of the 12 pilot subcarriers included in the interference suppression region belong to three pilot index sets, that is, 1-4 belongs to 5~ 8 belongs to 9~12 belongs to ί3⁄4. When performing channel estimation:

The estimated channel coefficients on all data subcarriers in the third channel estimation unit are , with:

Where | | represents the pilot index set

The number of pilot subcarriers included in the combination.

Application example nine

The interference suppression region in this application example is the interference suppression region pattern 3. As shown in FIG. 11, the interference suppression region is divided into two channel estimation units, and the indexes of the 12 pilot subcarriers included in the interference suppression region belong to Two pilot index sets, of which 1~8 belong to, 9~12 belong to ί3⁄4. When performing channel estimation: The estimated channel coefficients on all data subcarriers in the first channel estimation unit are 3⁄4, with:

^ 8 12

;=1 i=9

1=1

The number of pilot subcarriers included in the packet.

Application example ten

It contains 15 consecutive OFDM/OFDMA symbols and contains 4 consecutive subcarriers in the frequency domain, which carry two data streams.

In this example, there are 20 pilot subcarriers corresponding to the two data streams, and the interference suppression region is divided into two channel estimation units. For each data stream, the index of the corresponding 20 pilot subcarriers belongs to two pilot index sets, wherein the pilot subcarrier index 1~4 belongs to, and the index 5~10 belongs to.

When performing channel estimation on the data subcarrier position corresponding to the first data stream:

The channel coefficient estimates on all data subcarriers corresponding to the first data stream in the first channel estimation unit are:

The channel coefficient estimates on all data subcarriers corresponding to the first data stream in the second channel estimation unit are:

^ 4 10

h = «21 ( ⁺ "22∑ {ή

i=l i=5

Wherein, the channel coefficient estimation at each pilot subcarrier position corresponding to the first data stream Counting, satisfying the condition | | =i , o≤3⁄4≤i , Λ = ι,2, | | indicates the pilot index set

1=1

The number of pilot subcarriers included.

When channel estimation is performed on the data subcarrier position corresponding to the second data stream: the channel coefficient estimates on all data subcarriers corresponding to the second data stream in the first channel estimation unit are 3⁄4 ² , and have:

The channel coefficient estimates for all data subcarriers corresponding to the second data stream in the second channel estimation unit are both ² , with:

Wherein: the channel coefficient estimation value at each pilot subcarrier position corresponding to the second data stream satisfies the condition | | =l , ≤ a _k ' _l ≤\ , k = \, 2, | | represents the pilot index In the collection

1=1

The number of pilot subcarriers included.

Application example eleven

It contains 6 consecutive OFDM/OFDMA symbols and contains 6 consecutive subcarriers in the frequency domain, which carry two data streams.

In this example, the interference suppression region is divided into one channel estimation unit, and the indexes of the four pilot subcarriers corresponding to each data stream in the interference suppression region belong to one pilot index set ^, that is, 1 to 4 The pilot subcarriers corresponding to different data streams are different. When performing channel estimation on the data subcarrier position corresponding to the first data stream:

The channel coefficient estimates on the data subcarriers corresponding to the first data stream in the channel estimation unit are both:

^ 4 where is the channel coefficient estimate for each pilot subcarrier location corresponding to the first data stream The value, satisfies the condition | |«„=i, 0<α _η <1, || represents the number of pilot subcarriers included in the pilot index set.

When channel estimation is performed on the data subcarrier position corresponding to the second data stream: the channel coefficient estimation value on the data subcarrier corresponding to the second data stream in the channel estimation unit is 3⁄4 ² , and has:

^ 4 where is the channel coefficient estimate for each pilot subcarrier position corresponding to the second data stream, satisfying the condition | | =i, 0<« ₁ <1, | | indicating the guide included in the pilot index set The number of frequency subcarriers.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above application examples may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above application example may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial Applicability With the method and system of the present invention, channel estimation can be accurately performed when there is wideband co-channel interference in adjacent cells, thereby improving the performance of interference suppression and the accuracy of data detection.

Claims

Claim

1. A channel estimation method in a wideband co-channel interference environment, applied to a receiving end of an Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) system, in an interference suppression region, When performing channel estimation on a data stream that is carried, the method includes:

Multiplying a received signal on the pilot subcarrier by a conjugate of a pilot signal transmitted by the transmitting end on the pilot subcarrier for each pilot subcarrier corresponding to the data stream, to obtain the Estimating the channel coefficient of the pilot subcarrier position;

For each data subcarrier corresponding to the data stream, a weighted average of channel coefficient estimates of the pilot subcarrier positions corresponding to the data stream is used as an estimated channel coefficient of the data subcarrier position;

The interference suppression area is a time-frequency two-dimensional resource block in the received data bearer area.

2. The method of claim 1 wherein:

And the step of, as the step of estimating the channel coefficient of the data subcarrier position, the weighted average of the channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream for each data subcarrier corresponding to the data stream The calculation formula used in the following is as follows:

Wherein, the channel coefficient estimation value of the jth data subcarrier position corresponding to the data stream in the interference suppression area, j = i, - -, J, J is the data stream corresponding to the interference suppression area The number of data subcarriers; "When calculating the channel coefficient estimate for the first data subcarrier position, assign ^ (weight of 0, ∑«, = 1; ^ (0 is the interference suppression region The estimated channel coefficient of the second pilot subcarrier position corresponding to the data stream, = 1, · · ·, /, / is the number of pilot subcarriers corresponding to the data stream in the interference suppression region.

3. The method of claim 2, the method further comprising:

Before calculating the channel coefficient estimation value of the data subcarrier position according to the formula (a), the interference suppression region is divided into one or more channel estimation units, and each channel sound estimation unit is a time domain two-dimensional resource. a source block and including at least one pilot subcarrier and one data subcarrier;

Constraint 2, when calculating the channel coefficient estimates for each data subcarrier position in the same channel estimation unit, all set the same weight = ι,···, /, j = l, ', J.

4. The method of claim 1, the method further comprising:

The interference suppression area is divided into f channel estimation units, each channel sound estimation unit is a time domain two-dimensional resource block and includes at least one pilot subcarrier and one data subcarrier, where f is a positive integer;

And weighting average of channel coefficient estimates of the pilot subcarrier positions corresponding to the data stream for each data subcarrier corresponding to the data stream, as a channel coefficient estimate of the data subcarrier position In the steps, the calculation formula used is as follows:

1=1 where h _d ^k is the estimated channel coefficient of each data subcarrier position corresponding to the data stream in the A channel estimation unit, k = \, 2, --, K

/ is a loop variable, 1 = 1, 2, ···,Κ

When O _kl is a calculation, the weight of ^ (/) assigned to each pilot subcarrier position in the channel estimation unit, | | indicates the number of pilot subcarrier indices included.

5. The method of claim 4, wherein

Calculate the weight of 3⁄4釆 according to formula (b), where 3 = 4, 1 = \, 2, ---, K, greater than or equal to other weights.

6. The method of claim 1, wherein

And multiplying a received signal on the pilot subcarrier by a conjugate of a pilot signal sent by the transmitting end on the pilot subcarrier for each pilot subcarrier corresponding to the data stream, to obtain In the step of estimating the channel coefficient of the pilot subcarrier position, the calculation formula is as follows: P(i) = y _p (i)p*(i) (c)

The channel coefficient estimated value of the first pilot subcarrier position corresponding to the data stream in the interference suppression area is a received signal on the first pilot subcarrier, where is the transmitting end. a pilot signal transmitted on the first pilot subcarrier, (0 indicates that the conjugate is conjugated, ί = 1,···, Ι, / is the pilot subcarrier corresponding to the data stream in the interference suppression region Number.

7. A channel estimation system in a wideband co-channel interference environment, used for receiving at an orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) system, carrying it in an interference suppression region A data stream is used for channel estimation, and the interference suppression area is a time-frequency two-dimensional resource block in the received data bearer area, and the system includes:

a first device, configured to: for each pilot subcarrier corresponding to the data stream, the received signal on the pilot subcarrier and the pilot signal sent by the transmitting end on the pilot subcarrier Conjugating multiplication to obtain an estimated channel coefficient of the pilot subcarrier position;

a second device, configured to: perform weighted average of channel coefficient estimation values of pilot subcarrier positions corresponding to the data stream as the data subcarrier position for each data subcarrier corresponding to the data stream Estimated channel coefficient.

8. The channel estimation system of claim 7, wherein:

The second device is configured to use a weighted average of channel coefficient estimates of each pilot subcarrier position corresponding to the data stream for each data subcarrier corresponding to the data stream by using a calculation formula as follows Estimated channel coefficients for data subcarrier locations:

I

Hd(j) = _ij h _p (i) ( _3⁄4 )

i=l Wherein, the channel coefficient estimation value of the Jth data subcarrier position corresponding to the data stream in the interference suppression area, j = l, - -, J, J is the data stream corresponding to the interference suppression area The number of data subcarriers; "To calculate the channel coefficient estimate of the _; data subcarrier position, assign ^ (weight of 0, ∑«, = 1; is the data in the interference suppression region) The estimated channel coefficient of the first pilot subcarrier position corresponding to the stream, = 1, · · ·, /, / is the number of pilot subcarriers corresponding to the data stream in the interference suppression region.

9. The channel estimation system according to claim 8, wherein the channel estimation system further comprises: a third device configured to: divide the interference suppression region into one or more channel estimation units, each channel sound estimate The unit is a time domain two-dimensional resource block and includes at least one pilot subcarrier and one data subcarrier;

Constraint 2, when calculating the channel coefficient estimates for each data subcarrier position in the same channel estimation unit, all set the same weight = 1, · · ·, /, j = l, ', J.

The channel estimation system according to claim 7 or 8, the channel estimation system further comprising: a third device, configured to: divide the interference suppression region into f channel estimation units, each channel sound estimation The unit is a time domain two-dimensional resource block and includes at least one pilot subcarrier and one data subcarrier, where f is a positive integer;

Correspondingly, the second device is configured to: use each of the data subcarriers corresponding to the data stream by using the following calculation formula, and perform weighted average of channel coefficient estimation values of the pilot subcarrier positions corresponding to the data stream , as the channel coefficient estimate of the data subcarrier position:

/=1 ie Qf where h _d ^k is each data subcarrier bit corresponding to the data stream in the A channel estimation unit Estimated channel coefficient, k = 1, 2, ···, ,

/ is a loop variable, 1 = 1, 2, ···,Κ

a set of index I of pilot subcarriers corresponding to the data stream included in the channel estimation unit, = 1, ..., /, / is the number of pilot subcarriers corresponding to the data stream Λ( ) is an estimated channel coefficient of the first pilot subcarrier position corresponding to the data stream in the interference suppression region;

When O _M is calculated, the ^ (/) of each pilot subcarrier position in the channel estimation unit is given.

K

1=1

In the weight "3⁄4, 1 = 1, 2, ---, K, " is greater than or equal to other weights _t