KR20070024310A - Interference cancellation method and module for ofdma mobile communication system - Google Patents

Abstract

A receiving method and a module for canceling an interference in an OFDMA(Orthogonal Frequency Division Multiple Access) mobile communication system are provided to enhance a receiving performance of service base station signal by allowing a mobile terminal having single antenna to remove the interference from an adjacent base station in a cell boundary region. A receiving method for canceling an interference includes the steps of: receiving a sub carrier including data signals from a service base station, wherein an interference signal from an adjacent or remote base station is included in the data signals; estimating a channel response about the service base station and the adjacent base station by using more than one neighboring pilot sub carrier on a frequency axis or a time axis among the sub carrier; calculating a weight for removing an interference signal from the repeated data sub carriers by using the estimated channel response; and producing interference-removed data symbol by synthesizing more than one data sub carriers having a repeated same data symbol among the received sub carriers by using the weight.

Description

Receiving method and apparatus for canceling interference in OPDMA mobile communication system {Interference Cancellation Method and Module for OFDMA Mobile Communication System}

1 is a diagram illustrating a situation in which a mobile terminal located at a cell boundary receives a signal from a serving base station in the presence of interference signals from two neighboring base stations;

2 is a diagram illustrating a structure of a frame transmitted from a base station in an OFDMA mobile communication system;

3 illustrates a plurality of pilot subcarriers used as one channel estimation group in a channel estimation method between a base station and a mobile terminal;

4 is a diagram illustrating a method of synthesizing repeated subchannels and generating one subchannel;

5 is a block diagram schematically illustrating an interference cancellation apparatus of a mobile terminal having a single antenna according to the present invention;

6 is a flowchart illustrating a method for receiving interference cancellation in an OFDMA mobile communication system according to the present invention;

7 is a view for explaining a communication method with a base station to which transmit antenna diversity is applied;

8 is a block diagram schematically illustrating an interference cancellation apparatus of a mobile terminal having a plurality of antennas.

The present invention relates to a receiving method and apparatus for removing interference in an OFDMA mobile communication system. More specifically, in the Orthogonal Frequency Division Multiple Access (OFDMA) mobile communication system, when a mobile terminal located at a cell boundary area receives a data signal from a serving base station, the mobile station is adjacent to the neighboring cell. A method and apparatus for canceling interference received from a base station and a far base station.

In the OFDMA mobile communication system according to the IEEE 802.16 standard, a base station repeatedly transmits encoded data for a mobile terminal having a poor channel environment in signal transmission between a base station transmitter and a mobile terminal.

The mobile terminal estimates a channel response from the serving base station by using a pilot subcarrier transmitted from a base station transmitting a data (hereinafter referred to as a 'service base station'), and uses the same to determine a repeated data subcarrier. You are receiving data through a method of synthesis.

At this time, when the mobile terminal is located in the cell boundary region as shown in FIG. You will also receive interference.

However, the conventional data reception method is a method of receiving using a limited repetition rate without removing an interference signal from a neighboring base station, which causes a problem that cannot solve a serious interference situation occurring at a cell boundary.

Accordingly, in order to solve the interference situation occurring at the cell boundary, when the mobile terminal has multiple receiving antennas, a method of removing interference signals from neighboring base stations by using an interference cancellation reception method using multiple antennas. Is being used.

However, miniaturized mobile terminals are not easy to have multiple antennas. In addition, even if a plurality of antennas are mounted because the spacing between the antennas is not enough, the correlation between the antennas is large enough to not sufficiently obtain the interference cancellation performance. Accordingly, there is a need for a method and apparatus for canceling an interference signal from an adjacent base station in a mobile terminal having a single antenna.

In order to solve this problem, the present invention estimates the channel response through the pilot symbol of the sub-carrier when the mobile terminal located in the boundary area in the OFDMA mobile communication system receives a signal from the service base station, and uses the channel response A method and apparatus are provided for canceling interference received from adjacent base stations and far base stations by calculating composite weights.

In order to achieve the above technical problem, the present invention provides an interference cancellation reception method, comprising: (a) a data signal from a serving base station-a neighboring base station and a far base station from a serving base station; Receiving an interfering signal from-receiving a subcarrier comprising a; (b) estimating a channel response for the serving base station and the adjacent base station using one or more pilot subcarriers adjacent on the frequency axis or time axis of the subcarriers; (c) using the estimated channel response, calculating a weight for canceling the interference signal; And (d) synthesizing one or more data subcarriers having the same data symbol repeated among the received subcarriers using the weights to calculate the data symbols from which the interference signal has been removed.

In addition, in order to achieve the second technical problem of the present invention, when the mobile terminal receives a data signal from a service base station to which transmission antenna diversity using two transmission antennas is applied, it eliminates interference received from neighboring base stations. CLAIMS 1. A method comprising: (a) receiving a subcarrier from a serving base station, the data signal comprising a data signal, the data signal comprising interference signals from neighboring base stations and far base stations; (b) estimating a channel response for each transmit antenna of the serving base station and the adjacent base station using one or more pilot subcarriers adjacent on a frequency axis or a time axis among the subcarriers; (c) calculating weights for performing interference cancellation on received symbols for each transmit antenna using the estimated channel response for each transmit antenna; And (d) conjugating the received symbol received from one transmit antenna, and then synthesizing one or more data subcarriers having the same data symbol using weights to calculate the interference-free data symbol. It includes.

In addition, the present invention is an interference cancellation receiving apparatus, in order to achieve the third technical problem of the present invention, a reception apparatus for removing interference signals received from a neighboring base station in a mobile terminal, the neighboring to a data signal-a data signal from a service base station; A receiving antenna for receiving subcarriers, wherein the interference signals from the base station and the far base station are included; An FFT module for separating the received subcarriers into pilot subcarriers and data subcarriers; A simultaneous channel estimation module for receiving a pilot subcarrier from the FFT module and estimating a channel response for the serving base station and the neighboring base station; A weight calculation module for receiving a channel response and calculating a weight for interference cancellation; And a simultaneous interference cancellation detection module receiving weights from the weight calculation module, receiving data subcarriers from the FFT module, and outputting data symbols from which interference is removed.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In addition, when a part is said to "include" a certain component, it means that it may further include other components, without excluding other components unless otherwise stated.

In addition, the term module described herein refers to a unit for processing a specific function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

2 is a diagram illustrating a structure of a frame transmitted from a base station in the OFMDA mobile communication system.

In FIG. 2, the vertical axis refers to a subcarrier as a frequency axis. In addition, the horizontal axis represents a symbol as a time axis.

The frame transmitted from the base station is composed of a plurality of clusters, and each cluster is composed of a data subcarrier and a pilot subcarrier.

The base station repeatedly loads the same data on several data subcarriers to transmit the data to increase the energy of each data during data transmission. At this time, each base station preferably transmits the same position of the data subcarrier including the same data. This part will be described in detail with reference to FIG. 4.

Some pilot subcarriers constituting the cluster are used to estimate the channel response used to demodulate data symbols transmitted on the data subcarriers. The pilot subcarriers transmitted from each base station preferably have the same location.

In the conventional reception method, in order to demodulate data from a service base station, only a channel response between the service base station and the mobile terminal is generally estimated. However, in the cell boundary region where the interference is severe, successful data demodulation cannot be guaranteed unless the interference from the adjacent base station is effectively removed.

Accordingly, in order to remove the interference from the neighbor base station, not only the channel response to the serving base station but also the channel response between the neighbor base station and the mobile terminal must be estimated.

To this end, the mobile terminal sets If adjacent pilot subcarriers on the frequency axis in the received frame and It adjacent pilot subcarriers on the time axis to form one channel estimation group.

3 is a diagram illustrating a plurality of pilot subcarriers used as one channel estimation group in a channel estimation method between a base station and a mobile terminal.

In one channel estimation group for channel estimation between a base station and a mobile terminal, there are I pilot subcarriers, where I = If × It, and are adjacent on a frequency axis and a time axis within one channel estimation group. Therefore, the channel response is almost constant.

Here, FIG. 3 illustrates a channel estimation group in which eight received pilot subcarriers exist as I = 2 × 4.

I received pilot signals in one channel estimation group may be expressed as Equation (1).

Where J is the number of neighboring base stations belonging to the service base station and the interference cancellation target, h _j is the channel response with base station j, P _{i, j} is the i th transmission pilot symbol for base station j, and n _i is the i th pilot symbol position It means the interference signal from a base station of a remote base that is not adjacent to the background noise.

Here, Equation 1 may be expressed as a determinant as shown in Equation 2 below.

From this, joint channel estimation (JCE) according to Maximum Likehood (ML) in one channel estimation group is solved through Equation 3.

Equation 3 estimates a corresponding channel response using a pseudo inverse matrix of transmission pilot symbols known from received pilot symbols. For example, if the number of interference cancellation base stations is one (i.e., J = 2), and the channel estimation group consists of two pilots (i.e., I = 2), the channel response estimate is solved by solving the inverse matrix, as shown in Equation 4. Can be.

Here, in order for the inverse matrix to exist, the number of received pilots belonging to the channel estimation group must be at least equal to or greater than the number of base stations to be interference canceled. That is, I ≥ J. In order to reduce the channel estimation error due to noise, it is preferable to increase the range of the channel estimation group as long as the channel response hardly changes in the channel estimation group.

However, even if I? J is satisfied in the channel estimation, there may be no inverse matrix depending on the configuration of the transmission pilot symbol. In this case, within the channel estimation group, channel response for each base station is independently estimated as in Equation 5 below.

4 is a diagram illustrating a method of synthesizing repeated subchannels and generating one subchannel.

 One subchannel consists of a plurality of data subcarriers, and when R repeated transmissions are applied, each subchannel is repeatedly transmitted R times. Therefore, the data subcarriers containing the same data are transmitted repeatedly R times and located at different positions on the frequency axis.

The mobile terminal detects data symbols while eliminating interference from neighboring base stations by multiplying each data subcarrier repeatedly received R times by an appropriate weight. In this case, the composite weight is obtained using the channel response from each base station estimated in the previous simultaneous channel estimation process. The weight due to the minimum mean square error (MMSE: hereinafter referred to as 'MMSE') is obtained as follows.

here,

은 수신 신호대 잡음비(여기서, 잡음은 간섭제거 대상이 아닌 원거리 기지국 신호를 포함)이다. 수학식 6은 서비스 기지국 뿐만 아니라 간섭 기지국 신호의 검출을 위해 사용되는 모든 가중치를 동시에 구하는 것이다. 그러나, 서비스 기지국에 대한 신호 검출만을 수행하는 경우에는 서비스 기지국에 해당되는 가중치 만을 계산하거나 사용하면 된다. 즉, W에서 j=1 번째 행 벡터 w_j만을 사용한다.I _J is an identity matrix with 1 as the diagonal of J × J, R is the number of repetitions, w _{j , r} is the composite weight for the base station j and r-th repetition symbol positions, and h _{r, j} is the r-th Estimated channel response with base station j at repeat symbol position, c _{r , j} are scrambling chips used at base station j at r th repeat symbol position, X ^H is the Transpose and Conjugate matrix of X,

Is the received signal-to-noise ratio, where noise includes the far base station signal that is not subject to interference cancellation. Equation 6 simultaneously calculates all weights used for detection of not only the serving base station but also the interfering base station signal. However, when performing only signal detection for a service base station, only the weight corresponding to the service base station needs to be calculated or used. In other words, only the j = 1 th row vector w _{j in} W is used.

The weight for each base station calculated by Equation 6 takes into account the signal-to-noise ratio in the R-dimensional signal space and serves to obtain a weight vector of the signal direction of the base station while being orthogonal to signals from other base stations.

The weight obtained by Equation 6 is used for synthesis reception as shown in Equation 7 below.

Where z _j is a detected data symbol for base station j and r _r is a data subcarrier value received at the r th repetition symbol position.

Equation 7 simultaneously detects data for not only the serving base station but also the interfering base station. When detecting only the signal for the serving base station, Equation 7 is calculated using the equation z _j = w _j r.

In joint detection (JD) according to Equations 6 and 7, the weight is calculated and synthesized in the direction of eliminating interference symbols at the same time as the synthesis reception for the repeated symbols, and thus detection by interference cancellation is possible.

In addition, in the weight calculation, unlike the equation (6), the weight by the zero forcing (ZF: hereinafter referred to as 'ZF') method is calculated as in Equation 8.

The weight calculation according to Equation 8 has an advantage of not using the received signal-to-noise ratio value, while the performance may be degraded when the received signal-to-noise ratio is small.

5 is a block diagram schematically illustrating an interference cancellation apparatus of a mobile terminal having a single antenna according to the present invention.

The interference cancellation apparatus according to the present invention includes a reception antenna 510, a fast fourier transform (FFT) module 520, a simultaneous channel estimation module 530, a weight calculation module 540, a simultaneous interference cancellation detection module 550, and a channel. The decryption module 560 is included. Here, the description of the part for converting the RF signal into the digital baseband signal is well known to those skilled in the art and will be omitted.

The receiving antenna 510 is a part for receiving data transmitted from a serving base station and a signal of an adjacent base station.

The FFT module 520 is a part which is received through the receiving antenna 510 and converts the signal converted into the baseband signal into a frequency domain signal.

Here, the signal received at the pilot subcarrier position among the converted frequency domain signals is input to the simultaneous channel estimation module 530, and the signal received at the data subcarrier position is input to the simultaneous interference cancellation detection module 550.

The joint channel estimation module 530 estimates the channel response to the serving base station and the interfering base station by using the received pilot signal and the transmitted pilot symbols of each base station and transmits the received channel signal to the weight calculation module 540.

The weight calculation module 540 calculates a weight for removing interference by using the channel response transmitted from the simultaneous channel estimation module 530.

The simultaneous interference cancellation detection module 550 outputs the detected data symbol by canceling the interference by using the weight calculated through the weight calculation module 540 and the data subcarriers transmitted from the FFT module 520.

The detected data symbol is transmitted to a channel decoder 560, and the channel decoder 560 outputs the decoded data.

6 is a flowchart illustrating a method for receiving interference cancellation in an OFDMA mobile communication system according to the present invention.

The mobile terminal located in the cell boundary region receives a serving base station and a subcarrier transmitted from an adjacent base station (S610).

The mobile terminal distinguishes a subcarrier received through the FFT module 520 into a pilot subcarrier and a data subcarrier. The pilot subcarrier is identified to form a channel estimation group for estimating a channel response (S620).

When the channel estimation group is formed, the pilot signal is expressed in a determinant as shown in Equation 2, and the simultaneous channel estimation module 530 determines whether an inverse of the channel estimation group exists (S630). When the existence of the inverse matrix is confirmed, the channel response is estimated using Equation 3 through the identified inverse matrix (S640). When it is confirmed that the inverse matrix does not exist, Equation 5 is independently used for each base station. The channel response is estimated (S650).

When the channel response is estimated, the weight calculation module 540 calculates the weight using the MMSE method according to Equation 6 or the ZF method according to Equation 8 (S660).

The simultaneous interference cancellation detection module 550 synthesizes weights according to Equation 7 to detect a signal from which interference has been removed (S670).

Through such a method, a mobile terminal can receive a signal from which interference from a plurality of base stations is removed in an OFDMA mobile communication system.

Meanwhile, the interference cancellation reception method according to the present invention can be applied to a case where a transmission antenna diversity is applied in a base station transmitting a subcarrier, that is, a transmission using a plurality of antennas.

7 is a diagram for describing a communication method with a base station to which transmit antenna diversity is applied.

Here, a description will be given based on a base station transmitting a subcarrier using two antennas. The base station according to FIG. 7 performs subcarrier transmission using a first antenna and a second antenna.

When two transmission symbols are grouped and the transmission symbol transmitted at the first symbol position is s ₍₁₎ and the transmission symbol transmitted at the second symbol position is s ₍₂₎ , a 2 × 2 based on Alamouti method is used. The space-time block code (STBC) transmission matrix is represented by the following equation (9).

             First antenna second antenna

First symbol s ₍₁₎ s ₍₂₎

Second symbol -s ₍₂₎ ^* s ₍₁₎ ^*

In order to use the same transmission power as when the base station uses one transmission antenna in Equation 9, each antenna divides the power value used for transmission in half in the case of a single antenna and uses it for each transmission.

In order to estimate a channel for each antenna in a mobile terminal, a base station must independently transmit a pilot signal for each antenna. Generally, a pilot symbol is transmitted only at a first antenna at a first symbol position, and a second antenna at a second symbol position. Only use the method of transmitting pilot symbols.

If the received symbol at the first symbol position is v ₍₁₎ and the received symbol at the second symbol position is v ₍₂₎ , the symbol received at the mobile terminal is expressed as in Equation (10).

Here, the channel response from the first antenna to the mobile terminal is _referred to as h ₍₁₎ , and the channel response from the second antenna to the mobile terminal is referred to as h ₍₂₎ . When conjugated to the second received symbol in Equation 10, Equation 11 is expressed.

을 생성하여 수학식 12에 의하여 구한다. In the process of detecting a transmission symbol, a channel response is estimated from a pilot symbol transmitted for each antenna, and a channel response matrix is obtained using the estimated channel response.

To be obtained by Equation 12.

The reception process in the case of using such a transmission antenna diversity with the interference cancellation reception method according to the present invention is as follows.

For channel response estimation for each antenna at the mobile terminal receiving the subcarrier, the base station groups the two symbols in units, transmits the pilot symbol only at the first antenna at the first symbol location, and at the second symbol location, the second antenna. The pilot symbol is transmitted using only.

At this time, when the transmission antenna diversity is used together, similar to the simultaneous channel estimation method according to Equation 3 when using a single transmission antenna, the simultaneous channel estimation (JCE) method in the mobile terminal is performed in each pilot channel estimation group. As shown in Equation 13, the channel is estimated using the received pilot symbol for each antenna.

Here, P ₍₁₎ is the matrix for the transmission pilot symbol at the first symbol position, and P ₍₂₎ is the matrix for the transmission pilot symbol at the second symbol position. And y ₍₁₎ is a matrix for the received pilot symbol at the first symbol position and y ₍₂₎ is a matrix for the received pilot symbol at the second symbol position.

In this case, since each antenna uses pilot symbols at different symbol positions, when the number of pilot symbols belonging to the pilot estimation group is I when using a single antenna, when using transmit antenna diversity using two antennas, The channel response for each base station and antenna is estimated using I / 2 received pilot symbols for each antenna.

On the other hand, as in the case of a single antenna, when the inverse matrix does not exist in Equation 13, channel estimation is independently performed for each antenna and the base station as in Equation 14.

Using the channel response for each base station and antenna estimated by Equation 13 or Equation 14, the weight for simultaneous detection (JD) is calculated using Equation 6 or Equation 8, which is a weighting method when a single transmission antenna is used. The same can be calculated by However, there is a difference in that the estimated channel response includes a process of detecting a symbol transmitted by two antennas over two symbols as shown in Equation 15 together.

Here, the weight by the MMSE method is calculated by the equation (15).

h _{r, j, (1)} is the estimated channel response for the first antenna of base station j at the r th repetition symbol position, and h _{r, j, (2)} is the second antenna of base station j at the r th repetition symbol position Is the estimated channel response for.

On the other hand, the weight by the ZF method is calculated by the equation (16).

As described above, the weight calculated by Equation 15 or Equation 16 is a weight for transmission of two symbols using two transmission antennas at the base station, and is twice as large as when using a single transmission antenna.

The symbol detection process using the same is performed in units of two symbols as in the simultaneous detection (JD). Prior to the simultaneous detection process, each group consisting of two symbols is conjugated to the second symbol, and the transmission symbol is detected by Equation 17.

Here, z _{j (1)} is the data symbol of the first symbol position detected for base station j, and z _{j (2)} is the data symbol of the second symbol position detected for base station j. And r _{r (1)} is the received symbol value of the r th repetition symbol position with respect to the data symbol at the first symbol position, and r _{r (2)} is the reception of the r th repetition symbol position with respect to the data symbol at the second symbol position. The symbol value. Where r ^* _{r (2)} is the conjugate of r _{r (2)} .

As described above, a method of removing interference received from an adjacent base station when a mobile terminal having a single antenna is located in a cell boundary region and a method of removing interference when transmitting subcarriers from a base station using multiple antennas have been described. .

However, the interference cancellation method according to the present invention can be applied not only to a mobile terminal having a single antenna, but also to a mobile terminal having a plurality of antennas.

8 is a block diagram schematically illustrating an interference cancellation apparatus of a mobile terminal having a plurality of antennas.

A mobile terminal having a plurality of (N) antennas delivers subcarriers received through each antenna to each FFT module. To this end, the mobile terminal includes the same number of FFT modules as the antennas. Each FFT module separates the pilot subcarrier and the data subcarrier, and then transfers the pilot subcarrier to the simultaneous channel estimation module. The simultaneous channel estimation module estimates an independent channel response for each receive antenna using the N pilot subcarrier groups delivered in each FFT module. That is, N channel responses are estimated through the simultaneous channel estimation module.

Accordingly, in the process of calculating the weight, the weight calculation module needs to extend the matrix for each channel response and the received symbol by the number (N) of the receiving antennas as well as the repeated symbols.

In addition, in the process of detecting data symbols from which interference is removed by applying weights in the simultaneous interference cancellation detection module, the extended weights are extended not only to the repetitive symbols but also to the N data subcarriers received through each receiving antenna. By applying it, it is possible to detect data symbols from which interference has been removed.

Here, in FIG. 8, one simultaneous channel estimation module is configured to receive N, ie, N pilot subcarrier groups from N FFT modules, and perform N channel response estimation processes. However, it is also possible to use N simultaneous channel estimation modules to connect to each FFT module and to transmit each channel response estimated in the N simultaneous channel estimation modules to one weight calculation module.

However, in order to reduce the size of the mobile terminal, it is desirable to design the number N of antennas not to exceed two.

The embodiments of the present invention described above are not implemented only through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Implementation may be easily implemented by those skilled in the art from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the present invention, a mobile terminal having a single antenna can improve reception performance of a service base station signal by removing interference from neighboring base stations at a cell boundary region, thereby improving frequency in all cells. Can be reused, and the effect of increasing system capacity can be expected.

In addition, it is possible to successfully demodulate signals from the serving base station and the adjacent base station in the handoff situation from the cell boundary to the adjacent base station, thereby increasing the handoff success rate and reducing the handoff delay time.

Claims (24)

A method for removing interference signals received from neighboring base stations in a mobile terminal, (a) receiving a subcarrier comprising a data signal from a serving base station, the data signal comprising interference signals from the neighboring base station and the far base station; (b) estimating a channel response for the serving base station and the adjacent base station using one or more pilot subcarriers adjacent on a frequency axis or a time axis of the subcarriers; (c) using the estimated channel response, calculating a weight for removal of the interference signal from repeated data subcarriers; And (d) synthesizing one or more data subcarriers having the same data symbol repeated among the received subcarriers using the weights, and calculating data symbols from which the interference signal is removed; Interference cancellation reception method comprising a. The method of claim 1, wherein step (b) And combining one or more pilot subcarriers adjacent to the frequency axis or the time axis into one channel estimation group, and estimating the channel response using the channel estimation group. The method of claim 2, wherein step (b) comprises: If the pilot subcarrier number of the channel estimation group is equal to or greater than the number of neighboring base stations, If there is an inverse of the channel estimation group, the channel response is estimated through a simultaneous channel estimation method using the inverse matrix, And if there is no inverse of the channel estimation group, estimating respective channel responses for the serving base station and the neighboring base station. The method of claim 3, wherein the simultaneous channel estimation method using the inverse matrix

(here,

Is a vector constituting the channel responses h _j for each base station J in the channel estimation group, P is

, P _{i, j} is the i th transmit pilot symbol for base station j, y is a vector of received pilot symbols consisting of the received signals at the i th pilot symbol position) And estimating the channel response using the interference elimination method. The method of claim 3, wherein the method of estimating each channel response for the serving base station and the neighboring base station comprises:

(here,

Is an estimated channel response for base station j in the channel estimation group, p _{i, j} is an i th transmit pilot symbol for base station j, y _i is an i th received pilot symbol) Interference cancellation reception method characterized in that using. The method of claim 2, And receiving the subcarriers by using at least two receiving antennas, in the mobile terminal, calculating the channel response for each receiving antenna. The method of claim 1, wherein step (c) comprises: The method of claim 1, wherein the weight for the interference cancellation is calculated using a minimum mean square error (MMSE) method or a zero forcing (ZF) method. The method of claim 7, wherein the minimum mean square error method,

(here,

I _J is an identity matrix having 1 as an element at a diagonal of J × J, R is the number of repetitions, w _{j , r} is a weight for the r th repetition symbol position with respect to base station j, and h _{r, j} is the r The estimated channel response for the base station j at the iterative symbol position, c _{r , j} is the scrambling chip used at the base station j at the rth iterative symbol position, X ^H is Transpose and Conjugate of X procession,

Is the received signal-to-noise ratio, where noise includes interference from a far base station that is not subject to interference cancellation. The method for canceling interference according to claim 1, wherein the weights for the interference cancellation are calculated using the algorithm. The method of claim 7, wherein the zero forcing method,

(here,

I _J is an identity matrix having 1 as an element at a diagonal of J × J, R is the number of repetitions, w _{j, r} is a weight for the r th repetition symbol position with respect to base station j, and h _{r, j} is the r The estimated channel response for the base station j at the iterative symbol position, c _{r, j} is the scrambling chip used at the base station j at the rth iterative symbol position, X ^H is Transpose and Conjugate of X procession) The method for canceling interference according to claim 1, wherein the weights for the interference cancellation are calculated using the algorithm. The method of claim 7, wherein step (c) is When the mobile station receives the subcarriers using two or more receiving antennas, the weight is calculated by using the repeated same data symbols and channel responses for each of the two or more receiving antennas. Receiving method. The method of claim 1, wherein step (d)

(Where z _j is a data symbol detected for base station j and r _r is a data subcarrier value received at the r th repetition symbol position) And synthesizing a plurality of data subcarriers having the same repeated data symbols among the subcarriers. A method for removing interference received from an adjacent base station when a mobile terminal receives a data signal from a serving base station to which transmit antenna diversity using two transmit antennas is applied, (a) receiving a subcarrier containing a data signal from the serving base station, wherein the data signal includes interference signals from the neighboring base station and the far base station; (b) estimating a channel response for each transmit antenna of the serving base station and the adjacent base station using one or more pilot subcarriers adjacent on a frequency axis or a time axis of the subcarriers; (c) calculating weights for performing interference cancellation on received symbols for each transmit antenna using the estimated channel response for each transmit antenna; And (d) conjugating the received symbol received by one transmit antenna, and then synthesizing one or more data subcarriers having the same data symbol using the weights to calculate the interference-free data symbol. step Interference cancellation reception method comprising a. The method of claim 12, wherein step (b) comprises: And the number of adjacent pilot subcarriers on the frequency axis or time axis is greater than or equal to twice the number of the serving base station and the neighboring base station. The channel response of claim 12, wherein the channel response for each transmit antenna is

Where P ₍₁₎ is the matrix for the transmission pilot symbol at the first symbol location, P ₍₂₎ is the matrix for the transmission pilot symbol at the second symbol location, y ₍₁₎ is at the first symbol location A matrix for the received pilot symbol in which y ₍₂₎ is the matrix for the received pilot symbol at the second symbol location The interference cancellation reception method characterized in that it is calculated by. The method according to claim 13, wherein if there is no inverse of P ₍₁₎ or P ₍₂₎ ,

And calculating a channel response for each transmitting antenna by using the interference elimination reception method. The method of claim 12, And receiving the subcarriers using two or more receiving antennas in the mobile terminal, calculating a channel response for each transmitting antenna for each receiving antenna. The method of claim 12, wherein step (c) comprises:

(here,

h _{r, j, (1)} is the estimated channel response for the first antenna of base station j at the r th repetition symbol position, and h _{r, j, (2)} is the first response of the base station j at the r th repetition symbol position Estimated channel response for 2 antennas) The method for canceling interference, characterized in that to calculate the weight for the interference cancellation by the Minimum Mean Square Error (MMSE) method. The method of claim 12, wherein step (c) comprises:

(here,

h _{r, j, (1)} is the estimated channel response for the first antenna of base station j at the r th repetition symbol position, and h _{r, j, (2)} is the first response of the base station j at the r th repetition symbol position Estimated channel response for 2 antennas) And calculating a weight for the interference cancellation using a zero forcing (ZF) method. The method of claim 12, wherein step (d)

Where z _{j (1)} is the data symbol of the first symbol position detected for base station j, z _{j (2)} is the data symbol of the second symbol position detected for base station j, and r _{r (1)} is The received symbol value of the r th repetition symbol position with respect to the data symbol of the first symbol position, r _{r (2)} is the received symbol value of the r th repetitive symbol position with respect to the data symbol of the second symbol position, r ^* _{r (2)} is the conjugate of r _{r (2)} ) And calculating a symbol from which the interference is removed through the interference elimination reception method. A reception device for removing an interference signal received from an adjacent base station in a mobile terminal, A receiving antenna for receiving a subcarrier including a data signal from a serving base station, the data signal including an interference signal from the neighboring base station; A Fast Fourier Transform (FFT) module for separating the received subcarriers into pilot subcarriers and data subcarriers; A simultaneous channel estimation module for receiving the pilot subcarrier from the FFT module and estimating a channel response for the serving base station and the neighboring base station; A weight calculation module for receiving the channel response and calculating a weight for the interference cancellation; And A simultaneous interference cancellation detection module receiving the weight from the weight calculation module and receiving the data subcarrier from the FFT module and outputting the data symbol from which the interference is removed Interference cancellation receiving apparatus comprising a. The apparatus of claim 20, wherein the interference cancellation receiver is provided. And receiving subcarriers from the serving base station and the neighboring base station through at least two receiving antennas. The apparatus of claim 21, wherein the interference cancellation reception apparatus is provided. An FFT module of the same number as the receiving antenna is included, and the FFT module is connected to each of the two or more receiving antennas, and separates the subcarriers received from each receiving antenna into pilot subcarriers and data subcarriers. Interference Cancellation Receiver. The apparatus of claim 22, wherein the interference cancellation reception apparatus is And a simultaneous channel estimation module having the same number as the FFT module, wherein the simultaneous channel estimation module receives pilot subcarriers separated from the respective FFT modules, and estimates each channel response. Device. The apparatus of claim 20, wherein the interference cancellation receiver is provided. A channel decoding module for performing decoding on the data symbol from which the interference is removed and outputting the decoded data Interference cancellation receiving apparatus further comprises.

Images