KR100948940B1 - Pilot emitting relay and channel estimation method using the same - Google Patents

Abstract

The present invention relates to a pilot emitting repeater and a channel estimating method using the same, which can be applied to various systems such as a single subcarrier system, an OFDM system, and a multiple antenna system without consuming additional resources, and a transmitter using the same. And a pilot emitting repeater capable of independently estimating a channel with a repeater and a channel estimating method using the same.

The present invention for achieving this characteristic object, the power measuring unit for measuring the power of the signal for the frame frequency band; And a PET section setting unit configured to set a PET section by detecting a TTG or RTG section of the base station and the terminal. Including, but the repeater, characterized in that for transmitting the pilot signal in the PET section to the base station and the terminal.

Pilot signal, repeater

Description

Pilot-Emitting Repeater and Channel Estimation Method Using Them {PILOT EMITTING RELAY AND CHANNEL ESTIMATION METHOD USING THE SAME}

The present invention relates to a pilot emitter repeater and a channel estimating method using the same, and more particularly, a pilot emitter repeater that can be applied to various systems such as a single subcarrier system, an OFDM system, and a multiple antenna system without consuming additional resources. The present invention relates to a pilot emitting repeater capable of independently estimating a channel with a repeater using the same and a channel estimation method using the same.

Recently, a wireless mobile communication system using a repeater has been widely studied in an attempt to increase a communication distance or a reception performance in a mobile communication system. The repeater is divided into a full duplexing repeater for transmitting and receiving at the same time and a half duplexing repeater for transmitting and receiving at separate times according to a transmission and reception protocol.

In addition, an amplify-and-forward (AF) method for amplifying and retransmitting a signal received from a source as it is, and a DF (decode-and-forward) for decoding and retransmitting a signal received from a source to remove the effects of thermal noise. )

The present invention proposes a repeater for transmitting a pilot. The pilot signal transmitted from the repeater can be used for various purposes. In the case of a time division duplex (TDD) system, a base station can be used to estimate a channel using channel reciprocity, and a terminal can be used to independently estimate a repeater and a terminal channel. Independent channel estimation made in such a base station and a terminal can improve the performance of the communication system between the base station and the terminal using the repeater.

In the case of a repeater operating in a full duplex communication method, an echo cancellation method and apparatus for canceling the signal transmitted from the output terminal of the repeater are input to the input terminal of the repeater. To this end, echo signal channel estimation is required between the output terminal and the input terminal of the repeater, and the pilot signal transmitted from the repeater may be used for the purpose of estimating the echo signal channel.

At this time, the transmission of the pilot signal in the repeater is made in the PET (Pilot Emitting Time) section. The PET section may be allocated separately in the frame, but this has the disadvantage of causing capacity reduction due to additional resource allocation and changing the frame structure of the existing system.

On the other hand, in the patent "Method and apparatus for closed loop transmission" published by Motorola Inc. has proposed a method for transmitting a channel sounding signal to the terminal as a method for the base station to know the channel. Assuming that the terminal is a repeater in this patent, this patent can be considered similar to the prior art. In the channel sounding method, the base station transmits a control signal to the repeater so that the repeater transmits the channel sounding signal in the appropriate frequency-time domain to obtain channel information. The base station may estimate a channel between the base station and the repeater in the frequency band corresponding to the signal using the channel sounding signal received from the repeater. This technique allocates specific frequency-time resources for the channel sounding signal transmitted by the repeater. In other words, Motorola's prior art means that additional resources are needed for channel sounding.

In the above-mentioned prior art, the base station transmits a control signal to the repeater for frequency-time resource allocation for the channel sounding signal. In order to obtain the frequency-time resource allocation information transmitted by the base station, the repeater must go through channel estimation and received signal decoding processes between the base station and the repeater. Therefore, since a repeater requires a channel estimator and decoder, the implementation of the repeater is complicated and expensive, thereby reducing the cost of using the repeater in terms of cost. In addition, since channel estimation and reception signal decoding generally require a great deal of processing time, it may not be suitable to perform a decoding process in a wireless communication system requiring a quality of service (QoS) sensitive to time delay, such as a voice call. have.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the pilot-emitting repeater which can be applied to various systems such as a single subcarrier system, an OFDM system, and a multi-antenna system without consuming additional resources, and a transmitter and a receiver using the same Its purpose is to provide a pilot emitting repeater capable of independently estimating a channel with a repeater and a channel estimation method using the same.

The present invention relates to a pilot emitting repeater, comprising: a power measuring unit for measuring power of a signal for a corresponding frame frequency band; And a PET section setting unit configured to set a PET section by detecting a TTG or RTG section of the base station and the terminal. Including, but the repeater, characterized in that for transmitting the pilot signal in the PET section to the base station and the terminal.

Meanwhile, the present invention relates to a frequency domain channel estimation method, comprising: (a) allocating pilots at equal intervals in the frequency domain more than the number of channel taps; (b) transmitting a sample of a minimum unit repeated after the IFFT process to the receiving end; (c) performing an FFT processor by repeating the sample received in the PET section at the receiving end; And (d) taking interpolation to estimate frequency domain channel; Characterized in that it comprises a.

According to the present invention as described above, there is an effect that can be applied to a variety of systems, such as a single sub-carrier system, OFDM system, multiple antenna system, without consuming additional resources.

In addition, according to the present invention, the repeater transmits a pilot signal in the PET period, which is a frame idle period, so that the transmitter and the receiver can estimate the channel with the repeater independently of the entire channel in the existing system, thereby providing the transmitter and the relay period. It also has the effect of improving communication performance.

Specific features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. In the meantime, when it is determined that the detailed description of the known functions and configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, it should be noted that the detailed description is omitted.

The present invention will be described in detail with reference to the accompanying drawings.

A pilot emitting repeater according to the present invention and a channel estimation method using the same will be described with reference to FIGS. 1 to 9.

1 is an exemplary view illustrating that a repeater transmits a pilot signal, and the pilot signal transmission is performed in the PET section in the repeater. This pilot signal can be used for various purposes, such as:

1. Through the pilot signal transmitted from the repeater, as shown in FIG. 2, the base station and the terminal can obtain additional channel information. The pilot signal transmitted by the repeater may be respectively received by the base station and the terminal of the communication system using the repeater. The base station can use this to estimate the channel between the repeater and the base station. In the case of a TDD system, channel information estimated from a base station and a relay period may be utilized by using channel interactivity. The terminal can also estimate the repeater and the terminal channel independently. Through the pilot signal transmitted from the repeater, the base station and the terminal obtain channel information between the base station and the repeater, the repeater and the terminal, respectively, thereby improving transmission and reception performance between the base station and the terminal.

2. Through the pilot signal transmitted from the repeater, the channel estimation of the echo signal for the echo signal cancellation technique can be performed as shown in FIG. In the case of a repeater operating in a full-duplex communication method, since the signal transmitted from the output terminal of the repeater enters the input terminal of the repeater, there is a need for a method and device for canceling the echo signal to cancel it. For this purpose, the repeater requires echo signal channel estimation between the output and the input, and the pilot signal transmitted from the repeater may be used for the purpose of estimating the echo signal channel. The echo signal channel estimation is possible even when the repeater has multiple antennas and a combination of multiple and single transmit / receive antennas, as shown in FIG.

In the repeater, the pilot signal is transmitted in the PET section. Here, the PET section may be a TTG section, an RTG section, or a portion thereof. For example, as shown in FIG. 5, the pilot transmission time of the repeater in the IEEE 802.16 Mobile WiMax system may be part of the TTG and RTG intervals, which are the time between the uplink subframe and the downlink subframe.

In general, since a symbol length of a communication system using a single subcarrier is shorter than a length of a TTG and RTG section, a method of using a TTG and RTG section as a PET section is immediately applicable in a communication system using a single subcarrier.

A system using OFDM receives a transmission signal as fast as a Frourier transform (FFT), and after serial-to-parallel (S / P) processing, inverse FFT (IFFT) and a cyclic prefix (CP) is added thereto. Create an OFDM symbol. In the OFDM communication system, transmission is performed in units of FFT-sized OFDM symbols, and thus, the length of one OFDM symbol interval is relatively longer than that of a single subcarrier. Therefore, one OFDM symbol interval is likely to be larger than the TTG and RTG interval lengths.

Therefore, it may be a problem to directly use TTG and RTG as the PET interval in the OFDM system. However, if the transmission and reception process in the manner described below, it can be applied to OFDM.

In the present invention, one application technology using the TTG and RTG sections as PET sections is shown. In the IEEE 802.16 draft Mobile WiMax system using OFDM, one OFDM symbol time is 115.2us, the TTG interval length is 87.2us, and the RTG interval length is 74.4us. Since one frame is composed of 42 OFDM symbols, one frame is 5ms long.

In order to use TTG and RTG as a PET section, the PET section should be shorter than the TTG and RTG sections. If it is assumed that the PET section is 1/4 of the OFDM symbol, the length of the PET section is 28.8us (= 115.2us x 1/4). This is a much shorter interval compared to 87.2us and 74.4us of TTG and RTG time. Originally, the TTG and RTG intervals are spare intervals for switching between transmission and reception operations, and this time can be used because they are designed to be comfortable compared to the actual switching time of the base station and the terminal, and the repeater transmits a pilot in this interval. The base station and the terminal can estimate the channel.

As shown in FIG. 5, when the RTG section between the uplink (UL) subframe and the downlink (DL) subframe is used as a PET, the terminal transmits after the uplink (UL) frame ends before the PET section. Mode is switched from the reception mode to the reception mode, the base station switches from the reception mode to the transmission mode after the end of the PET period, before the DL period.

In the present invention, a downlink is mainly assumed and wireless communication between a base station and a terminal is referred to. However, the invention is also applicable to uplink, where the base station can be a receiver and the terminal can also be a receiver.

It also assumes a general wireless communication system as well as a cellular environment. That is, the base station can be thought of as a device for transmitting data, and the terminal can be considered as a device for receiving data. The reverse is also possible.

The transmitter can operate in a bundle of several transmitters that do not cooperate or cooperate with each other, and the receiver can also operate in a bundle of multiple receivers that do not cooperate or cooperate with each other. The operation of the pilot emitting repeater includes the case where one repeater operates and all the cases where several repeaters operate.

Hereinafter, the present invention will be described in detail based on the functional description and assumptions as described above.

6 is a block diagram of a pilot emitting repeater 100 according to the present invention, as shown in the power measuring unit 110, the base station 200 and the terminal (measurement of the power of the signal for the frame frequency band) In the case of the PET section setting unit 120 for setting the PET section by detecting the TTG or RTG section of 300) and the repeater operating in a full-duplex communication method, an echo signal for canceling the signal transmitted from the output terminal when the signal is received back to the input terminal It includes a remover 130.

The pilot emitting repeater (hereinafter, referred to as a 'relay') 100 having the above-described configuration may be variously applied to a case where one repeater is applied and a system to which a plurality of repeaters are applied. Hereinafter, a single subcarrier system This section describes the application to OFDM, OFDM, and multi-antenna systems.

First, in a single subcarrier system having one repeater, the pilot signal transmission of the repeater 100 is made by PET time. In the up and down frame structure of the wireless communication system, all or part of the TTG and RTG interval may be a PET interval.

In order for the repeater 100 to set the PET section, first, a process of recognizing the TTG and RTG sections is required. The repeater 100 may correctly recognize the TTG and RTG sections through frame synchronization. However, frame synchronization requires a process of converting a received signal into a baseband signal and a process of converting a received analog signal into a digital signal. In order for the repeater to perform the above process, an RF up / down converter device and an A / D converter device are additionally needed, and thus the cost of implementing the repeater increases.

Therefore, the repeater 100 under consideration in the present invention is a pilot emitting AF repeater operating in the analog stage. The repeater recognizes the TTG and RTG intervals as power measurement operations.

That is, the repeater 100 proposed in the present invention measures signal power for the corresponding frame frequency band, and then detects a TTG or RTG section in which all base stations and terminals do not transmit a signal and finds a PET section. And a pilot signal is transmitted during this period. At this time, the PET section should be shorter than the TTG and RTG sections. The base station and the terminal detect the pilot signal transmitted from the repeater in the PET section, and estimates the base station and the repeater channel and the repeater and the terminal channel.

Also in an OFDM system, the pilot emitting operation is similar to a single subcarrier system. In the repeater 100, the pilot signal is transmitted in the PET section, and the TTG and RTG sections, which are the time between the uplink frame and the downlink frame, become the PET section. The pilot emitting repeater 100 measures the signal power for a predetermined frequency band to recognize the PET section. The pilot signal is transmitted during the PET period. All base stations and terminals receive the pilot signal transmitted from the repeater in the PET section, and estimate the base station and repeater channel and the repeater and terminal channel.

In addition, in a system having a plurality of repeaters, when there are a plurality of repeaters 100, there is interference between pilot signals transmitted from the repeaters. This causes the base station and the terminal to degrade the channel estimation performance of the base station and the relay period and the channel estimation performance between the relay and the terminal, respectively. Therefore, it is necessary to reduce the interference between pilot signals transmitted from each repeater 100. This can be solved by designing pilot signals having orthogonality to each other. Orthogonal pilot signals can be designed to have frequency domain orthogonality, time domain orthogonality, and code domain orthogonality. Or orthogonal through a combination thereof.

And, in a multiple input multiple output (MIMO) system, the repeater 100 may have a single transmit antenna and a single receive antenna, or may have multiple transmit antennas and multiple receive antennas. It may also have a single transmit antenna and multiple receive antennas or multiple transmit antennas and a single receive antenna. The base station and the terminal may also have a single transmit antenna and receive antenna, and multiple antennas and receive antenna, respectively.

That is, when the repeater 100 has multiple antennas, the pilot signals transmitted from each antenna in the PET section should be orthogonal to each other, and the pilot signals may have frequency domain orthogonality, time domain orthogonality, and code domain orthogonality. Or orthogonal through a combination thereof.

Next, a channel estimation method in a single subcarrier system and an OFDM system using a PET interval will be described.

First, in a single subcarrier system, the repeater 100 transmits a pilot signal in a PET section, the base station and the terminal know the PET section, and the repeater corresponding to the channel of the base station and the relay period and the channel between the repeater and the terminal to be estimated Suppose it has information about a pilot signal to transmit.

In this case, the base station and the terminal are generally the channel of the base station and the relay period and the channel between the repeater and the terminal through a well-known LS (least squares) channel estimator, a MMSE (minimum mean square error) channel estimator, etc. Can be estimated.

In addition, the OFDM system may be divided into a frequency domain channel estimation method and a time domain channel estimation method, and the frequency domain channel estimation flow using the PET interval in the OFDM system will be described below with reference to FIGS. 7 to 9.

It is assumed that the PET interval is 1/4 of the OFDM symbol, and the concept is as shown in FIG. In detail, referring to FIG. 8, pilots are allocated at equal intervals in the frequency domain more than the number of channel taps (S10), and a sample of the minimum unit repeated after the IFFT process is transmitted to the receiver (S20). Subsequently, the receiver receives an FFT processor by repeating the samples received in the PET section (S30), and takes interpolation to estimate the frequency domain channel (S40).

As described above, when the frequency domain channel estimation method using the PET interval is applied, the following results can be predicted.

1. Since we performed truncation compared to estimating an OFDM symbol, some signal-to-noise ratio (SNR) is reduced to obtain the same mean square error (MSE). Will be required more. This is a loss caused by reducing resource usage by a quarter.

2. The operating signal-to-noise ratio range for a given environment can be in the high SNR range of 30 to 35 dB. This is reasonable because a scenario of transmitting a pilot signal with a high transmission power during a short PET period.

3. Directly applicable to cellular environment

When several repeaters simultaneously transmit a pilot signal in the PET section, interference between adjacent repeater pilot signals occurs. To solve this, interference can be avoided by assigning different pilot groups to adjacent repeaters as shown in FIG.

At this time, there is a trade-off according to the PET section, and by reducing the PET section more, a lot of pilot groups can be generated to avoid interference from various repeaters. However, SNR loss occurs due to reduced resource usage. Pilot pattern design is needed to suppress interference from multiple repeaters in channel estimation in the time domain.

Next, channel estimation in the time domain using the PET interval in the OFDM system is as follows.

By assigning more pilot samples than the number of taps of the channel to be estimated in the time domain, it is possible to estimate ML (maximum likelihood). Similar to the channel estimation method in the frequency domain, the channel estimation in the time domain may be extended to cellular. If the pilot signal is designed to have orthogonality between the pilot signals of each repeater, each base station and the terminal can distinguish the pilot signal for each repeater from the pilot signal. As an example of pilot signal design for orthogonality, the pilot signals of the repeaters may be designed to have code orthogonality using Walsh code or PN (pseudo noise sequence). After time-domain channel estimation, an FFT may be taken on a channel to obtain a frequency-domain channel response.

Next, a communication method using a repeater 100 structure according to the present invention for transmitting a pilot signal will be described.

1. Closed loop MIMO transmission method

A multi-antenna transmission / reception system can be classified into an open-loop transmission technique in which the transmitter does not know the channel information and a closed loop transmission technique in which the transmitter knows the channel information. In consideration of the downlink of the MIMO system, when the base station knows channel information between the base station and the terminal, a closed loop MIMO transmission method may be used. Closed loop MIMO transmission means using the channel information between the base station and the terminal known to the base station, multiply each transmission antenna by the transmission preprocessing value to increase the wireless communication performance.

The repeater 100 according to the present invention transmits a pilot signal in the PET section. Therefore, the repeater acts as a transmitting end in the existing closed loop MIMO structure. In this case, the base station may estimate a channel between the repeater and the base station using the pilot signal transmitted from the repeater. In the case of the TDD system, channel information between the base station and the repeater may be utilized based on channel interactivity at the base station. Thus, the base station may use a closed loop MIMO transmission scheme for the repeater. In addition, the terminal may estimate the channel between the repeater and the terminal by using the pilot signal transmitted from the repeater and then use the estimated value when detecting the MIMO signal. Through this, the wireless communication performance can be improved by obtaining a higher effective channel value for the base station and the repeater link and the link between the repeater and the terminal than the existing repeater.

Specifically, assuming a repeater for AF transmission, the advantages of the structure of the repeater 100 for transmitting a pilot signal in the PET section according to the present invention compared to the repeater does not transmit a pilot signal in the PET section as follows. First, consider the case where the repeater has a single antenna and the base station and the terminal have multiple antennas. At this time, when the pilot signal is transmitted using the PET interval and the base station and the relay channel information are estimated using the PET interval, the base station compared to the system for estimating the complex effective channel information passing through the base station-repeater-terminal without using the PET interval. Can generate a better transmission weight vector. This is because the repeater uses a single antenna, so that the same pilot resources can be used to obtain better channel estimation performance at the base station. As the channel estimation error is smaller, the transmission antenna weight vector can be generated using information closer to the actual channel. Second, consider the case where the repeater, base station and terminal all have multiple antennas. At this time, when the pilot signal is transmitted using the PET interval, MIMO channel information between the repeater and the terminal can be estimated. Considering the existing repeater for the AF transmission, since the terminal can only estimate the effective channel information for the base station-relay-terminal, the noise finally received at the terminal becomes non-white noise. Non-white noise can result in overall system performance degradation. However, when using a multi-antenna repeater transmitting a pilot signal in the PET section, it is possible to estimate the channel information for the link between the repeater and the terminal, so that the whitening of the non-white noise can be used. Can be improved.

In addition, assuming that the repeater 100 transmits a pilot signal using a PET section without the limitation of the AF repeater and the number of antennas in the repeater, the terminal additionally uses channel link information between the repeater and the terminal. Thus, a more efficient receive antenna combining vector can be generated. In addition, when the terminal detects a signal after generating the combining vector, the system detection performance can be improved by using additional channel link information between the relay and the terminal.

2. Echo channel estimation method

The repeater operating in the half-duplex communication means a communication method in which a signal receiving process and a transmitting process cannot be performed at the same time. The half-duplex repeater operating in the time division method performs a reception process for one time interval and transmits at another time. This reduces the amount of signal the repeater relays in half. In order to solve this problem, a full duplex communication scheme may be considered. However, in the case of a wireless repeater operating in a full-duplex communication method, the output of the repeater comes back into the input of the repeater due to the radio characteristics. Since the echo signal degrades the performance of the repeater, there is a need for an echo signal cancellation technique for removing the echo signal.

Echo signal channel estimation is necessary to apply echo signal cancellation to full-duplex repeaters, which requires additional frequency and time resources.

When the TTG or RTG section proposed by the present invention is used as a PET section, an echo signal channel can be estimated without consuming additional frequency and time resources.

As shown in FIG. 3, the echo channel estimation may be performed in the case where there is one transmitting antenna and one receiving antenna of the repeater 100, and when the transmitting and receiving antennas of the repeater 100 are multiple as shown in FIG. 4, or It is applicable to all combinations of transmit and receive antennas such as single transmit antenna and multiple receive antenna, multiple transmit antenna and single receive antenna.

3. Transmission / reception method using network coding

When using a transmission / reception method using network coding, the repeater will receive signals from one or more transmitters. It is up to the network coding method to generate a signal after receiving it, decoding it, and transmitting it again. If a repeater considers a method of coherently receiving signals from one or more transmitters, a repeater for transmitting a pilot proposed by the present invention is required.

When the TTG or RTG section is used as the PET section, a transmitter using a network coding method can obtain channel information from the transmitter to the repeater without consuming additional frequency and time resources. The transmitter can perform transmission processing using channel information, thereby improving communication performance.

4. Transmission / reception method using superimposed pilot signal

The pilot signal is transmitted by allocating additional resources in the time and frequency domain. However, a transmission / reception method using a superimposed pilot signal that allocates a portion of data interval transmission power for pilot signal transmission without consuming additional frequency and time resources may be considered. Although it is not a concept of transmitting a pilot signal using a PET interval, the overlapping proposed by the present invention is performed in order to estimate the channel between the base station and the relay period and the channel between the repeater and the terminal at the base station and the terminal, respectively without consuming additional frequency and time resources. A repeater using a transmission / reception method using a pilot signal is required.

Particularly, in a high signal-to-noise ratio environment, even if the data interval transmission power is slightly reduced, performance deterioration does not occur significantly. Therefore, communication performance can be improved by transmitting a superimposed pilot signal in a repeater in an environment having a high signal-to-noise ratio.

As described above and described with reference to a preferred embodiment for illustrating the technical idea of the present invention, the present invention is not limited to the configuration and operation as shown and described as described above, it is a deviation from the scope of the technical idea It will be understood by those skilled in the art that many modifications and variations can be made to the invention without departing from the scope of the invention. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

1 is an exemplary view showing a repeater transmitting a pilot signal according to an embodiment of the present invention.

2 is an exemplary view showing a repeater transmitting a pilot signal in a cellular environment according to an embodiment of the present invention.

3 is an exemplary view showing a repeater having a single antenna for estimating an echo signal channel according to an embodiment of the present invention.

4 is an exemplary view illustrating a repeater having multiple antennas for estimating an echo signal channel according to an embodiment of the present invention.

5 is an exemplary view showing a frame structure using TTG and RTG as PET according to an embodiment of the present invention.

6 is a block diagram of a repeater according to an embodiment of the present invention.

7 is an exemplary view illustrating a frequency domain channel estimation concept using a PET section in an OFDM system according to an embodiment of the present invention.

8 is a flowchart illustrating a frequency domain channel estimation method using a PET section in an OFDM system according to an embodiment of the present invention.

9 illustrates an example of allocating a pilot signal when there are a plurality of repeaters in one cellular network according to an embodiment of the present invention.

Claims (20)

In the repeater 100 for relaying a transmission signal between the base station 200 and the terminal 300 in a single sub-carrier system and an OFDM system comprising a repeater, A power measuring unit 110 measuring power of a signal for a corresponding frame frequency band; And A PET section setting unit 120 for setting a PET section by detecting a TTG or RTG section of the base station 200 and the terminal 300; Including, but the repeater 100, the pilot emitting repeater, characterized in that for transmitting the pilot signal in the PET interval to the base station (200) and the terminal (300). The method of claim 1, The base station 200 and the terminal 300, A channel between the base station 200 and the repeater 100 through a LS (Least Square) channel estimator and a minimum mean square error (MMSE) channel estimator, and the terminal 300 and the repeater 100 Pilot emitting repeater, characterized in that for estimating the channel between. The method of claim 1, The PET section, the pilot emitting repeater, characterized in that all or part of the TTG or RTG section. The method of claim 1, The signal of the TTG and RTG interval, the base station 200 and the terminal 300, the pilot emitter repeater, characterized in that the section does not transmit a signal. In the repeater 100 for relaying the transmission signal between the base station 200 and the terminal 300 in a system having a plurality of repeaters, A power measuring unit 110 measuring power of a signal for a corresponding frame frequency band; And A PET section setting unit 120 for setting a PET section by detecting a TTG or RTG section of the base station 200 and the terminal 300; Including; The repeater 100 transmits a pilot signal to the base station 200 and the terminal 300 in the PET section, wherein each pilot signal transmitted from each repeater 100 has orthogonality to each other. Emitting Repeater. The method of claim 5, And the pilot signal is a signal having at least one orthogonality among frequency domain orthogonality, time domain orthogonality, and code domain orthogonality. The method of claim 5, And the pilot signal is a signal having orthogonality by a combination of a frequency domain, a time domain, and a code domain. In the repeater having a plurality of antennas to relay the transmission signal between the base station 200 and the terminal 300 in a multiple antenna system (MIMO), A power measuring unit 110 measuring power of a signal for a corresponding frame frequency band; And A PET section setting unit 120 for setting a PET section by detecting a TTG or RTG section of the base station 200 and the terminal 300; It includes, The repeater 100, The pilot signal is transmitted to the base station 200 and the terminal 300 in the PET interval, each pilot signal transmitted from each antenna is characterized in that the orthogonality to each other Meeting repeater. The method of claim 8, And the pilot signal is a signal having at least one orthogonality among frequency domain orthogonality, time domain orthogonality, and code domain orthogonality. The method of claim 8, And the pilot signal is a signal having orthogonality by a combination of a frequency domain, a time domain, and a code domain. The method of claim 8, When the repeater 100 is a TDD system, And a channel estimation between the base station (200) and the repeater (100) and a channel between the terminal (300) and the repeater (100) independently using channel interactivity. The method of claim 8, The repeater (100), the pilot emitting repeater, characterized in that for transmitting and receiving using a signal through a network coding scheme with the base station (200). The method of claim 8, The repeater (100), the pilot emitting repeater, characterized in that for transmitting a signal containing an overlapping pilot signal. In the repeater 100 to relay the transmission signal between the base station 200 and the terminal 300 in a system where a plurality of repeaters having a plurality of antennas, A power measuring unit 110 measuring power of a signal for a corresponding frame frequency band; And A PET section setting unit 120 for setting a PET section by detecting a TTG or RTG section of the base station 200 and the terminal 300; Including; The repeater 100 transmits a pilot signal to the base station 200 and the terminal 300 in a PET section, and each pilot signal transmitted from each repeater 100 has orthogonality to each other, And each pilot signal transmitted is orthogonal to each other. The method of claim 14, The repeater 100 transmits a pilot signal of a PET section in a closed loop multiple antenna system (MIMO) to the base station 200, And the base station (200) generates a transmit antenna weight vector through a pilot signal of the PET section transmitted from the repeater (100). The method of claim 14, Pilot-emitting repeater, characterized in that the non-white noise received by the terminal 300 through the pilot signal of the PET interval transmitted from the repeater (100). The method of claim 14, Pilot emitting repeater, characterized in that the terminal 300 generates a combining vector through a pilot signal of the PET interval transmitted from the repeater (100). The method of claim 14, Pilot emitting repeater, characterized in that for the terminal 300 to detect a multi-antenna system (MIMO) signal through a pilot signal of the PET interval transmitted from the repeater (100). In the full-duplex communication repeater 100 for estimating the echo signal channel, A power measuring unit 110 measuring power of a signal for a corresponding frame frequency band; PET section setting unit 120 for detecting the TTG or RTG section of the base station 200 and the terminal 300 to set the PET section; And An echo signal canceller 130 for canceling the signal transmitted from the output terminal when the signal is received again by the input terminal; Including, The repeater (100), the pilot emitting repeater, characterized in that for estimating the echo signal by transmitting a pilot signal in the PET interval. delete

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