KR20070081945A - Transmitting/receiving apparatus and method in an orthogonal frequedncy division multiplexing system and using the smae - Google Patents

Abstract

A transmitting/receiving apparatus and a method in an orthogonal frequency division multiple system with a channel interference signal, and a system thereof are provided to increase transmission efficiency by performing rate matching without transmitting a pilot signal and/or a data signal to be allocated to a subcarrier band removed due to CCI(Co-Channel Interference) filtering. A transmitting apparatus in an orthogonal frequency division multiple system includes a transmission controller(505) and a transmission module. The transmission controller(505) generates position information of a removed pilot subcarrier corresponding to a position of a CCI signal and control information including at least one of parameters for filtering the CCI signal. The transmission module generates and transmits a transmission stream and the control information as an OFDM symbol through a wireless network. The transmission module includes a pilot symbol generator(511) and a power booster(513).

Description

Transmitting and Receiving Apparatus and Method in Orthogonal Frequency Division Multiplexing System with Channel Interference Signal and Its System {TRANSMITTING / RECEIVING APPARATUS AND METHOD IN AN ORTHOGONAL FREQUEDNCY DIVISION MULTIPLEXING SYSTEM AND USING THE SMAE}

1 is a block diagram showing the configuration of a transmitter and a receiver in a typical OFDM system

2a to 2c are diagrams illustrating a method of arranging pilot signals in a transmission frame of a typical OFDM system

3 is a view showing a state in which analog TV signals are mixed in a frequency band used in a general DVB-H system;

FIG. 4 is a view illustrating a state in which a signal of a subcarrier adjacent to a CCI signal is also removed when a CCI filter is blocked in a typical OFDM system.

5 is a block diagram showing the configuration of a transmitter and a receiver in an OFDM system according to the present invention.

FIG. 6 is a diagram illustrating an example of implementing the CCI filter illustrated in FIG. 5.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission and reception apparatus and method for a wireless communication system, and more particularly, to an efficient transmission and reception apparatus and method in an orthogonal frequency division multiplexing (OFDM) system in which channel interference signals of the same frequency band exist. will be.

Today, due to the development of the communication industry and increasing user demand for packet data services, there is an increasing need for a wireless communication system capable of efficiently providing high speed packet data services. Existing communication networks have been developed mainly for voice services, which have disadvantages of relatively small data transmission bandwidth and high usage fee.

In such a wireless communication system, a transmission technique for transmitting and receiving packet data as well as voice at high speed, an equalizing technique for removing interference signals, a channel estimation technique, a synchronization technique, and a radio frequency (RF) technique And the like, and various technical attempts have been made to obtain maximum coverage with minimum transmission power. In this regard, a study on the OFDM scheme as a representative example of the broadband wireless access scheme is rapidly progressing.

The OFDM method is a transmission method using a multi-carrier, converts a symbol string input in series into a parallel signal, modulates and transmits through a plurality of sub-carriers having orthogonality. The OFDM scheme can be widely applied to a digital transmission technology that requires high-speed data transmission such as broadband wireless Internet, digital multimedia broadcasting (DMB), and wireless local area network (WLAN).

In the OFDM scheme, a frequency band is divided into a plurality of sub-bands, and a transmitter transmits a signal through subcarriers of each sub-band. For example, each subcarrier transmits a quadrature-amplitude modulation (QAM) signal, and the receiver demodulates and decodes the QAM signal to restore the original signal. A channel exists as a transmission medium between the transmitter and the receiver, and noise is present on the channel to distort reception by distorting a QAM signal transmitted through a subcarrier.

Therefore, in an OFDM system, a channel estimator generally compensates a channel for a distorted received signal and then performs demodulation.

1 is a block diagram showing the configuration of a transmitter and a receiver in a typical OFDM system.

In FIG. 1, the bit stream buffer 101 of the transmitter 100a receives a transport stream and control information and outputs a bit stream. In this case, the control information includes bit rate and code rate information required during the reception of the receiver 100b. The channel encoder 103 receives the bit stream and performs channel coding, and the rate matcher 105 performs rate matching for puncturing the coded bit stream to be transmitted through an actual OFDM symbol. Perform.

In FIG. 1, a symbol mapper 107 maps a rate-matched bit stream into a QAM symbol and outputs it to the multiplexer 111. In addition, the pilot symbol generator 109 generates a pilot symbol for channel estimation and outputs it to the multiplexer 111. The multiplexer 111 multiplexes the QAM symbol and the pilot symbol, and an inverse fast Fourier transform (IFFT) 113 converts the multiplexed frequency domain signal into a time domain signal. The IFFT-converted OFDM signal is filtered through a transmission (Tx) filter 115 to a signal of a predetermined service band and then transmitted to a wireless network through an RF stage (not shown). The OFDM signal transmitted to the wireless network is distorted by the noise component in the process of being transmitted through the wireless channel. The noise component may be analog TV signals transmitted through the same frequency band, and signal interference caused by the noise component is called Co-Channel Interference (CCI).

Meanwhile, in FIG. 1, the receiver 100b receives the distorted OFDM signal through an RF stage (not shown), and the CCI filter 117 performs filtering to remove adjacent channel interference (CCI) from the distorted OFDM signal. . The filtered OFDM signal is converted into a signal in the frequency domain through a fast Fourier transform (FFT) 119, and the demultiplexer 121 receives QAM symbols, pilot symbols, and control information from the received FFT transformed signal. Each output is demultiplexed. The channel estimator 125 estimates the channel through which the OFDM signal is transmitted using the pilot symbol, and the equalizer 123 removes the interference signal from the input QAM symbol using the channel estimate. The symbol mapper 129 demaps the input QAM symbol to output the bit stream in the rate matched state, and the rate dematcher 131 transmits the bit stream filled with the data at the punctured position to the channel decoder 133. Output The channel decoder 133 decodes the input bit stream and restores the original signal.

In the general OFDM system, a typical method for channel estimation is based on a pilot signal, a method using decoded data in a decision directed method, and a channel is estimated without knowing data. There is a blind detection method and the like. In general, assuming coherent demodulation in an OFDM system, a transmitting end transmits a pilot signal for channel estimation, and a receiving end for coherent demodulation performs channel estimation based on the received pilot signal.

Hereinafter, a method of arranging pilot signals in a transmission frame of a conventional OFDM system will be briefly described with reference to FIGS. 2A to 2C.

In a typical OFDM system, the pilot arrangement scheme is classified into a block-type pilot arrangement, a comb-type pilot arrangement, and a lattice type according to the arrangement of the pilot signals on the frequency and time axis. -type) It is divided into pilot arrangement method. 2A illustrates the block type pilot arrangement, FIG. 2B illustrates the comb-type pilot arrangement, and FIG. 2C illustrates the lattice type pilot arrangement.

2A to 2C, the horizontal axis corresponds to the time axis and the vertical axis corresponds to the frequency axis, and the shaded portion indicated by reference numeral P1 represents a pilot signal.

In FIG. 1A, the block-type pilot arrangement scheme arranges pilot signals on all subcarriers of an OFDM symbol by arranging pilot signals for specific OFDM symbols on a time axis. This approach requires interpolation on the time axis to estimate the channel affecting the data signal. In FIG. 1B, the comb-type pilot arrangement scheme is a method of uniformly distributing a pilot signal in each OFDM symbol, in which a pilot signal is placed on the same subcarrier for all time. This method requires interpolation on the frequency axis to estimate the channels that affect the data signal. In FIG. 1C, the lattice-type pilot arrangement scheme is a scheme in which pilot signals are regularly arranged on both the time axis and the frequency axis. This method is suitable for varying channel environments and requires interpolation on both the time and frequency axes to estimate the channels that affect the data.

Regardless of which method is used in the pilot arrangement scheme, the transmitter of the OFDM system continuously transmits a fixed arrangement of pilot signals so that the receiver can obtain accurate channel information. In summary, a receiver of a conventional OFDM system performs an FFT on a received OFDM symbol and performs channel estimation based on pilot symbols to channel-compensate the output of the FFT to determine a QAM symbol carrying data, and decode the determined QAM symbol. The channel decoding may be performed by mapping.

In the OFDM scheme as described above, if there is no other service in the frequency band where the service is provided, the receiver will ensure stable reception performance. However, in a wireless communication service in which various communication systems coexist, frequency bands are always narrow, and in many cases, transmission signals of different communication systems are mixed in the same frequency band. A representative example is a DVB-H system using an OFDM scheme as a transmission scheme.

The DVB-H system uses UHF (Ultra High Frequency) band as a frequency band, which is a place where analog TV signals such as PAL and SECAM are already mixed. That is, FIG. 3 illustrates a state in which analog TV signals are mixed in a frequency band used in a general DVB-H system. In general, analog TV signals such as PAL / SECAM include a picture carrier 301 for transmitting image information, a color carrier 303 for transmitting color information, and a sound carrier for transmitting sound information. 305).

However, since the DVB-H system uses the frequency band 310 in which the analog TV signals are mixed, the carriers 301, 303, and 305 act as co-channel interference (CCI). Accordingly, since the reception performance is hindered when the CCI signal is received as it is, the receiver of the OFDM system should be provided with a CCI filter to remove CCI as shown in FIG. In this case, since the CCI filter should remove only the CCI part from the received transport stream, it is necessary to design a CCI filter having a sharp cut-off characteristic. An IIR filter is mainly used for this purpose. .

In reality, however, no matter how precisely the IIR filter is designed, the target CCI part cannot be removed, and adjacent subcarriers inevitably attenuate. 4 (A), (B), and (C) illustrate a problem in that pilot and data QAM symbols adjacent to the CCI signal are also removed during the blocking operation of the CCI filter, which significantly degrades the performance of the receiver. In addition, since the frequency band in which the analog TV signal is transmitted in each region may be different, the position of the CCI signal as shown in FIG. 3 may be changed. In this case, the CCI filter of the receiver may even remove a signal that is completely different from the actual CCI signal when there is no location information on the CCI signal.

The present invention provides an apparatus and method for transmitting and receiving an orthogonal frequency division multiplexing system suitable for a channel environment in which an analog interference signal exists, and a system thereof.

The present invention also provides a transmission and reception apparatus and method and system capable of efficiently removing adjacent channel interference signals in an orthogonal frequency division multiplexing system.

The present invention also provides a transmission apparatus and method and system for improving the transmission efficiency of the system by improving the pilot signal power in the orthogonal frequency division multiplexing system.

According to an embodiment of the present invention, a transmission apparatus of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist within the same frequency band includes position information of the removed pilot subcarriers corresponding to the position of the CCI signal and the CCI in the receiver. And a transmission controller for generating control information including at least one of the parameters for filtering the signal, and a transmission module for generating a transport stream and the control information in an OFDM symbol and transmitting the same to a wireless network.

In a transmission method of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band according to the present invention, the position information of the removed pilot subcarrier corresponding to the position of the CCI signal and the CCI in the receiver And generating control information including at least one of the parameters for filtering the signal, and generating the transport stream and the control information as an OFDM symbol and transmitting the same to the wireless network.

A receiving apparatus of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band according to the present invention includes control information including a poll value and bandwidth information for filtering the CCI signal from a transport stream. And a CCI filter for performing the filtering of the CCI signal by using the receiving module and the control information.

In a reception method of an orthogonal frequency division multiplex (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band according to the present invention, control information including a poll value and bandwidth information for filtering the CCI signal from a transport stream is included. And receiving the filtering and filtering the CCI signal using the control information.

An orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band according to the present invention comprises: a transmission controller for generating control information including at least one of parameters for filtering the CCI signal; A transmitter having a transmission module for generating a transport stream and the control information as an OFDM symbol and transmitting the control information to a wireless network, and a receiving module for receiving control information including a poll value and bandwidth information for filtering the CCI signal from the transport stream. And a receiver having a CCI filter for filtering the CCI signal using the control information.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

First, the basic concept of the present invention will be described. In the present invention, in an OFDM system that provides a service through a frequency band in which an analog TV signal exists, such as a VHF / UHF band, the transmitter is configured to transmit the analog TV signal through hardware itself or a broadcast protocol. The present invention proposes a transmission scheme for generating control information for verifying this information without transmitting pilot subcarriers and / or data subcarriers corresponding to a CCI location and transmitting the received network information of adjacent bands to a receiver. In addition, the present invention proposes a method of improving the transmission efficiency of the system by increasing the power of other pilot subcarriers with the power of subcarriers not transmitted by the transmitter. In addition, the receiver receives the control information, performs accurate CCI filtering and channel estimation, and performs accurate channel estimation with improved pilot power to improve reception performance.

5 is a block diagram showing the configuration of a transmitter and a receiver in an OFDM system according to the present invention.

First, referring to the operation of the transmitter 500a in FIG. 5, the bit stream buffer 501 receives a transport stream including service data and corresponds to a CCI location from the transmission (Tx) controller 503. Receives control information including position information of the pilot subcarrier and parameters for CCI filtering from the receiver 500b, and outputs the transport stream and the control information as a bit stream according to the bit rate. The control information includes bit rate and code rate information required in a reception process. The transmission controller 505 receives the network information stored in hardware or network information of an adjacent band through which an analog TV signal is transmitted through a broadcast protocol to generate the control information. The channel encoder 503 receives the bit stream and performs channel coding according to the code rate, and the rate matcher 505 punctures the coded bit stream to receive the coded bit stream and transmit the same through an actual OFDM symbol. Perform rate matching.

In FIG. 5, a symbol mapper 507 maps the rate matched bit stream to a QAM symbol and outputs the result to the multiplexer 515. In addition, according to the present invention, the pilot symbol generator 511 generates a pilot symbol carried in the remaining pilot subcarrier positions except for the pilot subcarrier corresponding to the CCI position, and outputs the pilot symbols to the power booster 513, and the power booster 513 The power of the remaining pilot subcarriers other than the pilot subcarrier corresponding to the CCI location is boosted, and the boosted pilot symbols are output to the multiplexer 515. The transmission controller 505 controls the operation of the pilot symbol generator 511 and the power booster 513.

The multiplexer 515 multiplexes the QAM symbol and the pilot symbol, and the IFFT 517 converts the multiplexed frequency domain signal into a time domain signal. The IFFT-converted OFDM signal is filtered through a transmission (Tx) filter 519 to a signal of a predetermined service band and then transmitted to a wireless network through an RF stage (not shown). The OFDM signal transmitted to the wireless network is distorted by the noise component during the transmission process as described in FIG. 1. In this case, it is assumed that the noise component is an analog TV signal transmitted through the same frequency band, that is, CCI.

On the other hand, referring to the operation of the receiver 500b in FIG. 5, the CCI filter 521 receiving a distorted OFDM signal through an unillustrated RF stage performs CCI filtering to remove adjacent channel interference (CCI) from the distorted OFDM signal. Do this. At this time, the reception (Rx) controller 531 extracts a pole value and a bandwidth value (BW value) of the CCI filter 521 as parameters for CCI filtering from the control information transmitted from the transmitter 500a. Transfer to filter 521. The CCI filtered OFDM signal is converted into a signal in the frequency domain through the FFT 523, and the demultiplexer 525 demultiplexes the QAM symbol, the pilot symbol, and the control information from the received FFT transformed signal, respectively. The channel estimator 529 estimates a channel on which an OFDM signal is transmitted using a pilot symbol. At this time, the reception controller 531 is a pilot not transmitted in consideration of CCI filtering from the control information transmitted from the transmitter 500a to the position information of the pilot subcarrier corresponding to the CCI position among the indexes of the pilot subcarriers according to the present invention. The index information of the subcarriers is transmitted to the channel estimator 529, and the channel estimator 529 performs channel estimation using the remaining pilot subcarriers except for the untransmitted pilot subcarriers.

The equalizer 527 then removes the interfering signal from the input QAM symbol using the channel estimate. The symbol mapper 533 demaps the input QAM symbol to output a bit stream in a rate matched state, and the rate dematcher 535 outputs a bit stream filled with data of a punctured position to the channel decoder 537. The channel decoder 537 decodes the input bit stream and restores the original signal. At this time, the reception controller 531 extracts bit rate (B) information from the control information and transfers it to the rate de-matcher 535, and extracts code rate (C) information to the channel decoder 537.

Therefore, according to the configuration of FIG. 5, the transmitter may transmit control information for CCI filtering and channel estimation, and the receiver may receive the control information to perform accurate CCI filtering and channel estimation to improve reception performance. Meanwhile, in the present embodiment, the transmitter and the receiver are configured to perform the channel estimation using the CCI filtering and the boosted pilot power, but the transmitter and the receiver may be configured to perform at least one of the CCI filtering and the boosting operation of the pilot power. In this case, the control information may optionally include corresponding parameter for the CCI filtering or location information of the pilot subcarrier to be removed.

Hereinafter, a detailed process of generating control information in the transmitter 500a of FIG. 5 and the features of the present invention for performing CCI filtering and channel estimation on the control information in the receiver 500b will be described in detail.

First, assuming that the number of damaged QAM data symbols in the CCI filtering operation is d _e , and that the number of damaged pilot symbols is p _e , the transmission controller transmits as little as d _e data during rate matching of the data link. The 505 may control the bit stream buffer 501 to lower the transmission rate of the bit stream. In general, since the broadcast service receives the stream service, the speed adjustment does not cause any problem in the audio / video playback of the receiver.

If the transmission bit rate is changed frequently, the transmission controller 505 may change the code rate itself. In this case, the demodulation operation of the receiver 550b can be smoothly included by including change information such as a code rate in the control information generated from the transmission controller 505. The control information is transmitted using some of the subcarriers, and if necessary, parameters related to rate matching may be properly adjusted to perform puncturing, and the related parameters may be transmitted as control information. The control information includes position information of pilot subcarriers removed through CCI filtering, which is used for interpolation operation in channel estimation of the receiver 500b. In addition, in the present invention, the pilot transmission power of the subcarrier position that is not removed is boosted as shown in Equation 1 to perform a more accurate channel estimation at the receiving end. In this case, the total transmit power is the same as before, but the actual pilot power is increased by the power of the subcarrier to be removed, thereby improving reception performance.

In Equation 1, P _e denotes a power of a pilot subcarrier removed corresponding to a CCI position.

Meanwhile, as shown in FIG. 3, when the frequency bands for transmitting analog TV signals are different, the positions of the CCI are different for each frequency band, and thus the stop band of the CCI filter 521 must be changed. Therefore, the design of the CCI filter 521 should be designed so that the stop band (variable stop band) is variable. To this end, in the present invention, as shown in FIG. 6, the CCI filter 521 is designed as a plurality of IIR filters 601, 603, and 605 connected by a cascading method, and each IIR filter 601, 603, and 605 has a corresponding stop band. It is used to remove video, color and sound carriers of analog TV signals according to the stop band. Since the stop band of the IIR filter is determined according to the pole position and the bandwidth of the IIR filter, each IIR filter has a pole value and a bandwidth (BW) extracted from the control information. value).

As described above, the control information transmitted from the transmitter in the present invention includes a bit rate, a code rate, a position of a pilot subcarrier corresponding to a CCI position, and a poll value and bandwidth information of a CCI filter as CCI parameters. The transmission of such control information causes little loss of additional transmission bandwidth. For example, in the case of DVB-H system, there are subcarriers allocated for a control signal called TPS, and some of the bits allocated for TPS transmission are reserved bits which are not used and thus may be used for other purposes. That is, Table 1 below shows, for example, TPS signaling information and its data format in a DVB-H system.

Looking at the current DVB-H standard, bit numbers s50 to s53 in Table 1 are set as reserved bits and thus can be used to transmit control information. In addition, unless the hierarchical modulation that supports both HP (High Priority) and LP (Low Priority) transmission is used in the DVB-H system, the bits of the bit numbers s27 to s35 in Table 1 are used. Some of these may also be used to transmit control information. It is therefore possible to apply the invention while maintaining compatibility with the current DVB-H standard.

In the present invention, in order to generate the control information, the broadcast transmitter or repeater of each region must already know network information indicating a neighboring band situation of the region, and the network information is previously set in hardware of a transmitter such as a terminal or a higher broadcast protocol. It can be obtained through the network information table. Of course, in the latter case, it is assumed that the broadcasting station transmits the network information and the repeater can decode some values of the control information. Knowing the network information means that the analog TV service is transmitted in the corresponding frequency band, that is, the position of the image, color, and sound carrier shown in FIG. 3 can be accurately known using the network information.

The transmission controller 505 of FIG. 5 may know the number of data subcarriers (de), the number of pilot subcarriers (pe), and location information corresponding to the CCI location by using the network information. Here, the position of each subcarrier may be represented by an index. In addition, the transmission controller 505 may use the network information to determine which code rate to use and what rate matching to perform, and how to determine the pole / zero position of the CCI filter. From this, the pole value and bandwidth of the CCI filter can be known. In the embodiment of the present invention, a method of using the reserved bit of the TPS as an example of transmitting the control information has been exemplified, but it may be transmitted by other methods.

Therefore, as described above, the transmitter 500a of the present invention can adjust the number of bits carried in one OFDM symbol by adjusting the output of the bit stream buffer 501, and through rate matching and substantial code rate adjustment In the presence of CCI, the most appropriate transmission parameter can be selected. In addition, the subcarrier signal corresponding to the CCI location is not transmitted, and substantial performance improvement can be expected by adding the surplus power to the pilot subcarrier transmission at another location. Meanwhile, in the receiver 500b of the present invention, the reception operation is performed in the same manner as in the general OFDM system until the control information is initially decoded. Even though there is a reception error due to CCI filtering, the control information generally requires strong channel coding. Therefore (for example, BCH coding in the case of DVB-H) there will be no difficulty in obtaining control information. The receiver 500b performs setting of the CCI filter 521 using the poll value and the bandwidth of the obtained control information, and the specific CCI filter 521 may be implemented in a cascade form as shown in FIG. 6. In addition, the reception controller 531 checks the index of the pilot subcarriers that are not transmitted in consideration of CCI filtering from the control information, passes them to the channel estimator 529, and checks the bit rate for rate de-matching and the code rate for channel decoding. By transmitting to the channel decoder 537 it is possible to improve the transmission efficiency of the OFDM system.

As described above, according to the present invention, rate matching without transmitting a pilot signal and / or data signal to be allocated to a subcarrier band lost due to CCI filtering in an OFDM system having a channel environment in which analog interference signals exist within the same frequency band. The transmission efficiency can be improved by performing the following. In addition, the present invention further allocates the power of the non-transmitted pilot signal and / or data signal when transmitting another pilot signal to increase the transmission power of the pilot subcarrier while increasing the coverage of the entire system while using the same transmission power as conventionally. You can. This improvement in transmission efficiency leads to an increase in coverage of the transmitter and the repeater, resulting in a reduction in the infrastructure cost for the broadcast service.

Claims (10)

A transmission apparatus of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band, A transmission controller for generating control information including at least one of position information of a pilot subcarrier removed corresponding to a position of the CCI signal and a parameter for filtering the CCI signal at a receiver; And a transmission module for generating a transport stream and the control information in an OFDM symbol and transmitting the same to a wireless network. The method of claim 1, The transmitting module is a pilot symbol generator for generating a pilot symbol carried on the remaining pilot subcarrier positions other than the pilot subcarrier corresponding to the position of the CCI signal; And a power booster for boosting the power of the remaining pilot subcarriers other than the pilot subcarrier corresponding to the position of the CCI signal. A transmission method of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band, Generating control information including at least one of position information of a pilot subcarrier removed corresponding to a position of the CCI signal and a parameter for filtering the CCI signal at a receiver; And generating a transport stream and the control information as an OFDM symbol and transmitting the same to a wireless network. The method of claim 3, wherein Generating a pilot symbol carried on the remaining pilot subcarrier positions except for the pilot subcarrier corresponding to the position of the CCI signal; And boosting power of the remaining pilot subcarriers other than the pilot subcarriers corresponding to the location of the CCI signal. A reception apparatus of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band, A receiving module for receiving control information including a poll value and bandwidth information for filtering the CCI signal from a transport stream; And a CCI filter for filtering the CCI signal using the control information. The method of claim 5, The control information further includes position information of a pilot subcarrier removed corresponding to the position of the CCI signal, And a channel estimator for performing channel estimation using the remaining pilot subcarriers, except for the removed pilot subcarriers. A reception method of an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist in the same frequency band, Receiving control information including a poll value and bandwidth information for filtering the CCI signal from a transport stream; Receiving the CCI signal by using the control information. The method of claim 7, wherein The control information further includes position information of a pilot subcarrier removed corresponding to the position of the CCI signal, The method of claim 1, further comprising performing channel estimation using the remaining pilot subcarriers, except for the removed pilot subcarriers. In an orthogonal frequency division multiplexing (OFDM) system in which adjacent channel interference (CCI) signals exist within the same frequency band, A transmitter comprising a transmission controller for generating control information including at least one of the parameters for filtering the CCI signal, a transmission module for generating a transport stream and the control information as an OFDM symbol and transmitting the same to a wireless network; And a receiving module for receiving control information including a poll value and bandwidth information for filtering the CCI signal from a transport stream, and a receiver having a CCI filter for filtering the CCI signal using the control information. Orthogonal frequency division multiplexing system characterized by. The method of claim 9, The control information further includes position information of the removed pilot subcarrier corresponding to the position of the CCI signal, The transmitter further includes a power booster for boosting the power of the remaining pilot subcarriers other than the pilot subcarriers corresponding to the position of the CCI signal, And the receiver further comprises a channel estimator for performing channel estimation using the remaining pilot subcarriers other than the pilot subcarriers removed corresponding to the position of the CCI signal.

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