KR20140011961A - Method for cooperative communication in wireless communication systems - Google Patents

Abstract

Disclosed are a cooperative communication method of a wireless communication system. In the cooperative communication method performed by the transmitting apparatus, the transmitting apparatus determines at least one signal transmission path including the at least one relay apparatus in consideration of the position of the terminal and the signal propagation delay time of each relay apparatus, and the determined at least one signal Signal is transmitted to the terminal using a transmission path. Accordingly, signals transmitted through different paths arrive within a cyclic prefix (CP) section and perform normal demodulation at the terminal, thereby improving quality of the received signal and data rate.

Description

Cooperative communication method of wireless communication system {METHOD FOR COOPERATIVE COMMUNICATION IN WIRELESS COMMUNICATION SYSTEMS}

The present invention relates to a wireless communication system, and more particularly, to a cooperative communication method using multiple beams in a wireless communication system.

Currently, the mobile communication system is developing in a direction in which the data transmission rate becomes extremely high. However, in a mobile communication system, a terminal located in a service area of a predetermined base station receives a service by using limited resources, and thus there is a limit in increasing service quality and service capacity. That is, since the base station must support a number of terminals located in the service area by using the limited radio resources, the radio resources are divided and allocated to each terminal, and each terminal is provided with a service using the resources allocated to the terminal, thereby transmitting data. There is a limit to improving speed and quality of service.

Meanwhile, the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) -Advanced system, a fourth generation mobile communication system, is a method for transmitting / receiving a coordinated multipoint (CoMP: CoMP) (CoMP) for increasing service capacity. Standardization is being promoted.

The CoMP transmission / reception method represents a transmission / reception operation between two or more points (site, cell, base station, distributed antenna, etc.) and one or more terminals. The CoMP transmission / reception method may be classified into a downlink CoMP transmission and an uplink CoMP reception operation.

Uplink CoMP reception is a method in which a predetermined terminal transmits a signal to a plurality of points geographically separated from each other, and joint reception of a signal received from the terminal at the plurality of points. In uplink CoMP reception, the UE does not need to know from which network node a signal is transmitted or what processing is performed on the received signal, and only needs to know what downlink signaling is provided in connection with the uplink transmission. . Therefore, uplink CoMP reception can be introduced without major changes in the specification of the air interface.

Downlink CoMP transmission is a method in which a plurality of points geographically separated from each other collaboratively transmit signals to one or more terminals. Downlink CoMP transmission can be divided into Joint Processing (JP) and Coordinated Beamforming / Coordinated Scheduling (CB / CS), and the Joint Processing scheme (JP) is again divided into multiple points. Joint Transmission (JT), which performs data transmission at the same time, and Dynamic Point Selection (DPS), which performs data transmission at one point and dynamically selects the point at which data is transmitted. ).

In the case of co-processing (JP) CoMP transmission, the terminal should be able to receive and process data transmitted from a plurality of transmission points, and if the terminal can process data transmitted from a plurality of transmission points, service capacity may be increased. Can be.

The cooperative beamforming / cooperative scheduling (CB / CS) method is a method of transmitting data to a terminal only at a serving point at a specific moment. As a passive method of avoiding interference between transmission points, a significant capacity increase effect is expected. Can't.

In addition, when data processing capacity beyond the limitation of the LTE-Advanced system is required, a method of reducing the length of a cyclic prefix (CP) inserted into an OFDM symbol from the present (for example, the length of the CP to the existing length) Decrease by 1/10) to improve data processing capacity. However, when the length of the CP is reduced in this way, in order to maintain orthogonality between OFDM subcarriers, signals passing through different paths must arrive at the receiving device within the reduced CP length, which is difficult to satisfy.

Meanwhile, a method of using a relay node to expand the coverage of the base station may be considered. However, in this case, a method of transmitting data in consideration of the position and processing delay time of each relay node is required in order for the terminal to demodulate the signals received through the plurality of relay nodes normally.

SUMMARY OF THE INVENTION An object of the present invention for overcoming the above disadvantages is to provide a cooperative communication method using multiple beams in a wireless communication system that can improve the reception signal quality or data transmission speed of a terminal in a cooperative communication environment using a relay device. will be.

In the cooperative communication method using multiple beams in a wireless communication system according to an aspect of the present invention for achieving the above object of the present invention, in the cooperative communication method performed in the transmitting apparatus, the location of the terminal and the signal of each relay device Determining at least one signal transmission path including at least one relay device in consideration of a propagation delay time, and transmitting a signal to a terminal using the determined at least one signal transmission path.

According to the cooperative communication method using multiple beams in the wireless communication system as described above, after the base station establishes the multipath in consideration of the location of the terminal and / or the service radius of the at least one relay node and processing delay time, Send a signal along the path. In addition, the base station determines a signal transmission time point in consideration of the propagation delay time of the transmission path and the processing delay time of at least one relay device included in the multipath so that a signal transmitted through the multipath arrives at the terminal within the CP period. .

Accordingly, the signals transmitted through the multipath may arrive at the terminal within the CP section, and thus the terminal can demodulate the received signals normally, thereby improving the quality of the received signal. In addition, when the base station transmits different data through the multi-path can further improve the data rate.

1 is a conceptual diagram illustrating the timing of a received signal in a wireless communication system using OFDM.
2 is a block diagram showing the configuration of a receiving apparatus for receiving a signal transmitted using spatial multiplexing.
3 is a block diagram showing a configuration of a receiving apparatus for receiving a signal transmitted using transmit diversity.
4 is a conceptual diagram illustrating a cooperative communication environment according to an embodiment of the present invention.
5 is a conceptual diagram illustrating a cooperative communication method according to an embodiment of the present invention.
6 is a conceptual diagram illustrating a cooperative communication method according to another embodiment of the present invention.
7 is a conceptual diagram illustrating a cooperative communication method according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

The term 'terminal' used in the present application includes a mobile station (MS), a mobile terminal (MT), a user terminal, a user equipment (UE), a user terminal (UT) An access terminal (AT), a subscriber unit, a subscriber station (SS), a wireless device, a wireless communication device, a wireless transmit / receive unit (WTRU) Or < / RTI > other terms.

In addition, the 'base station' used in the present application generally refers to a fixed point for communicating with a terminal, and includes a base station, a Node-B, an eNode-B, and a BTS. It may be called other terms such as a Base Transceiver System, an Access Point, or a Point.

In addition, the 'relay device' used in the present application may be referred to as a relay node, a relay node, a relay, a relay point, a point, a remote radio head (RRH), a remote radio unit (RRU), a site, a distributed antenna, or the like. And it refers to a transmission and reception device that is connected through a medium such as the base station and the optical fiber, microwave and can exchange information with the base station.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the same reference numerals will be used for the same constituent elements in the drawings, and redundant explanations for the same constituent elements will be omitted.

In a cooperative communication method of a wireless communication system according to the present invention, a base station and at least one relay device in a wireless communication environment in which a base station provides a service using a plurality of beams and each beam is configured to service a predetermined area. By providing the same data in cooperation with each other to improve the data reception quality of the terminal, or the base station and at least one relay device provides a method for improving the data rate by transmitting different data to the terminal.

In a system using an Orthogonal Frequency Division Multiplex (OFDM) scheme such as LTE and LTE-Advanced systems, orthogonality between subcarriers may be lost in the case of a channel in which a signal spreads in time (that is, in the case of a frequency selective channel). Accordingly, a cyclic prefix (hereinafter, abbreviated as 'CP') is inserted into an OFDM symbol so that the OFDM signal is not sensitive to the spread of a temporal signal in a wireless channel. CP insertion means copying the last part of an OFDM symbol and inserting it at the beginning of an OFDM pawn. Therefore, even if a signal transmitted from a base station arrives at a receiving device only within a CP period, even if the signals are transmitted through different paths, the orthogonality between subcarriers of the OFDM signal can be protected, so that the receiving device can demodulate the received signal normally.

FIG. 1 is a conceptual diagram illustrating timing of a reception signal in a wireless communication system using OFDM. FIG. 1 illustrates an example of a timing of a reception signal when different transmission apparatuses transmit data to a terminal through different beams. It is.

Referring to FIG. 1, when the first transmitting device 110 and the second transmitting device 130 transmit the same data to the terminal at time t using the first beam 111 and the second beam 131, respectively. The data transmitted from each of the first and second transmission devices 110 and 130 arrives at the reception device 150 through different transmission paths. At this time, the data transmitted from the first transmitting device 110 reaches the receiving device 150 after the propagation delay time of the radio section passes, and the data transmitted from the second transmitting device 130 receives the first transmitting device ( When the receiver 150 arrives within the CP section of the data transmitted by the controller 110, the receiver 150 may demodulate data received from the first transmitter 110 and the second transmitter 130 normally. Will be.

As illustrated in FIG. 1, it is necessary to adjust a data transmission time point so that an arrival delay time of data transmitted through different transmission paths is included in a CP period. In addition, when the data passes through the relay device, the processing delay time, which is a time required for processing and relaying the data received by the relay device, must also be taken into account.

For LTE and LTE-Advanced systems, CP defines two CP lengths, a normal CP and an extended CP. The general CP is about 4.7us and the extended CP has a time length of about 16.7us. . The length of the CP is sufficient to prevent the orthogonality of the OFDM signal from being damaged due to the difference in transmission delay time of the signal transmitted through different transmission paths in a general wireless communication system.

However, as the transmission capacity required in a wireless communication system increases, efforts have been made to improve an efficient frequency band, frequency bandwidth, or frame structure than a conventional wireless communication system.

For example, as higher frequency bands are used to secure frequencies, multi-path delays are reduced according to the surrounding environment, subcarrier spacing is increasing, and the frame structure of the system to be used. The length of one OFDM symbol is shortened. On the other hand, as the length of an OFDM symbol is shortened, the CP length inserted into the OFDM symbol is also significantly shorter than that of the conventional system. Even when the length of the CP is shortened, in order to demodulate the signal received by the receiving device normally, data arriving at the receiving device through different paths must arrive within the shortened CP section. It becomes difficult to satisfy.

The present invention provides a cooperative communication method capable of demodulating normally received data regardless of the length of a CP in a wireless communication environment in which a base station provides a service using multiple beams and each beam can transmit the same data or different data. To provide.

FIG. 2 is a block diagram illustrating a configuration of a receiving apparatus that receives a signal transmitted using spatial multiplexing, and illustrates a demodulation structure of the receiving apparatus when different data are transmitted through different beams in a plurality of transmitting apparatuses. will be. Here, the transmitting device may be, for example, a base station or at least one relay device, and the receiving device may be a terminal.

In FIG. 2, a reception device for receiving and processing data transmitted by the first transmission device 110 through the first beam 111 and data transmitted by the second transmission device 130 through the second beam 131 ( The configuration of 200 is illustrated as an example.

Referring to FIG. 2, the receiving apparatus 200 includes a plurality of antennas 210, a plurality of OFDM demodulators 220, a first channel measuring unit 221, a second channel measuring unit 222, and a first beamforming. The receiver 231, the second beamforming receiver 232, the interference canceller 240, and the decoder 250 may be included.

Each OFDM demodulator 220 performs OFDM demodulation on a signal received through a corresponding antenna 210 connected thereto, and then demodulates the demodulated data to the first beamforming receiver 231 and the second beamforming receiver 232. to provide.

The first channel measuring unit 221 measures a channel between the first transmitting device 110 and the receiving device 200 based on the signals received through the plurality of antennas 210 and outputs a channel measurement result to the first beam. The forming receiver 231 is provided.

The second channel measuring unit 222 measures a channel between the second transmitting device 130 and the receiving device 200 based on the signals received through the plurality of antennas 210 and outputs a channel measurement result to the second beam. The forming receiver 232 is provided.

Here, the first channel measuring unit 221 and the second channel measuring unit 222 may each measure a channel state based on a predefined reference symbol for channel measurement.

The first beamforming receiver 231 may perform the demodulation data provided from the plurality of OFDM demodulators 220 from the first transmitter 110 based on a channel measurement result provided from the first channel measurer 221. After the data transmitted through the first beam 111 is divided, the divided data is provided to the interference canceller 240.

The second beamforming receiver 232 may perform the demodulation data provided from the plurality of OFDM demodulators 220 from the second transmitter 130 based on the channel measurement result provided from the second channel measurer 222. After the data transmitted through the second beam 131 is divided, the divided data is provided to the interference canceller 240.

The interference canceller 240 performs continuous interference cancellation based on the data provided from the first beamforming receiver 231 and the second beamforming receiver 232 and the decoded data provided from the decoder 250. By canceling, the interference between the spatially multiplexed data is removed and then provided to the decoder 250. Here, the interference canceller 240 may use a continuous interference cancellation method based on minimum mean square error (MMSE).

The decoder 250 decodes the data provided from the interference canceling unit 240 to transmit the first transport block 261 and the second transport block 261 transmitted from the first transmission device 110 through the first beam 111. The second transport block 262 (Transport Block) transmitted through the second beam 131 is output from the transmission device 130.

3 is a block diagram illustrating a configuration of a receiver for receiving a signal transmitted by using transmit diversity, wherein a plurality of transmitters or one transmitter transmits the same data through different beams. Demodulation structure is illustrated. Here, the transmitting device may be, for example, a base station or at least one relay device, and the receiving device may be a terminal.

Referring to FIG. 3, the receiving apparatus 300 may include a plurality of antennas 310, a plurality of OFDM demodulators 320, a channel measuring unit 330, a combining unit 340, and a decoder 350. Can be.

Each OFDM demodulator 320 performs OFDM demodulation on a signal received through a corresponding antenna 310 connected thereto, and then provides demodulated data to the combining unit 340.

The channel measuring unit 330 measures a channel between the transmitting apparatuses and the receiving apparatus 300 based on the signals received through the plurality of antennas 310 and provides the channel measuring result to the combining unit 340. . The channel measuring unit 330 may measure a channel state based on a predefined reference symbol for measuring a channel.

The combining unit 340 performs combining on the demodulated data provided from the plurality of OFDM demodulator 320 based on the channel measurement result provided from the channel measuring unit 330, and then decodes 350. To provide. Here, the combining unit 340 may use a maximum ratio combining (MRC) technique for the provided data. Alternatively, when a plurality of transmitting devices transmit signals using Space Frequency Block Coding (SFBC) or Space Time Block Coding (STBC), SFBC decoding or STBC decoding may be performed.

The decoder 350 outputs the transport block 360 by decoding the data provided from the combining unit 340.

On the other hand, when the receiving device receives a signal through a plurality of different paths, it is possible to minimize the interference of the received signal by allocating different frequency resources at the same time, or by transmitting the signal using a time delay. However, this method has a disadvantage of low resource use efficiency.

Therefore, in the cooperative communication method of the wireless communication system according to an embodiment of the present invention, a plurality of transmitting apparatuses transmit data to a receiving apparatus using the same resources to improve demodulation performance, or the plurality of transmitting apparatuses are different. The present invention provides a method of improving data rate by transmitting data to one terminal.

In a wireless communication environment in which a base station and at least one relay device cooperate to transmit a signal, a signal transmitted by the base station may be transmitted to the terminal via at least one relay device. Here, the relay apparatus may be configured to receive a signal, amplify the received signal, and transmit the received signal again, or may include a separate scheduler to generate and transmit a new signal based on the signal received by the scheduler. In addition, when a signal is transmitted using a relay device, processing time is required to relay the signal received by each relay device.

Therefore, when the signal transmitted from the base station is transmitted to the terminal through the relay device, the delay time of each transmission path may be different, so that signals passing through a plurality of different transmission paths arrive at the receiving device within the CP interval You may not be able to. In particular, when the CP interval is short, the probability of such a phenomenon increases.

In the cooperative communication method according to an embodiment of the present invention, in consideration of the processing delay time and the transmission delay time of each relay device in order to solve the problems described above, the relay device in advance based on the time point at which the relay signal is received. A method of transmitting a signal after a predetermined time is used.

FIG. 4 is a conceptual diagram illustrating a cooperative communication environment according to an embodiment of the present invention, and illustrates four cases in which a terminal receives a signal through at most one relay device.

Referring to FIG. 4, in the first case (1), a signal transmitted by a base station 410 through specific beams Beam1 and Beam3 and relay devices 411 and 413 located in an area of the specific beams Beam1 and Beam3. This is the case in which the terminals 415 and 417 receive a signal transmitted through a beam formed by.

In the second case (2), when the terminal 425 receives a signal through beams formed by two relay devices 421 and 423 respectively located in a region of a specific beam Beam3 formed by the base station 410. to be.

In the third case (3), a signal transmitted by the terminal 431 through the first beam Beam1 formed by the base station 410 is different from the first beam Beam1 among the beams formed by the base station 410. This is a case where a signal transmitted through a beam formed by the relay device 433 positioned in the region of the second beam Beam2 is received.

In the fourth case (4), the terminal 445 signals through the beams formed by the two relay devices 441 and 443 respectively positioned in the two different beams Beam1 and Beam2 areas formed by the base station 410. If you receive.

In all four cases, the terminal must receive and process signals transmitted from the base station and the relay device or two relay devices. At this time, all signals transmitted to the terminal through different transmission paths must arrive at the terminal within the CP period.

In the present invention, the size of the service area of the relay device is adjusted so that the difference in the final delay time of the signals transmitted to the terminal via different paths is included in the CP section. That is, the radius r of the service area of the relay device is set to satisfy the equation (1).

When the relay device is configured such that the radius of the service area of the relay device satisfies Equation 1, the difference between the delay time between the signal received by the terminal from the base station or another relay device and the signal received through the relay device is smaller than the CP interval. do.

FIG. 5 is a conceptual diagram illustrating a cooperative communication method according to an embodiment of the present invention, illustrating an arrival time of signals received by a terminal in a cooperative communication environment of the third case shown in FIG. 4.

Referring to FIG. 5, when the base station 510 simultaneously transmits a signal at a time t using the first beam 511 and the second beam 513, the terminal located in the region of the first beam 511 ( 520 directly receives a signal from the base station 510 via the first beam 511. Meanwhile, the signal transmitted from the base station 510 through the second beam 513 is transmitted to the terminal 520 through the relay of the relay device 530 positioned in the region of the second beam 513. Here, the relay device 530 may form a separate beam to relay a signal to the terminal 520. That is, the terminal 520 receives a signal through the first path path1 directly formed with the base station 510 and the second path path2 via the relay device 530.

The signal transmitted from the base station 510 through the first path path1 may be transmitted after the propagation delay time corresponding to the distance between the base station 510 and the terminal 520 (eg, 3.3us) passes. Arrived at).

Meanwhile, since the signal received by the terminal 520 through the second path path2 passes through the relay device 530, the base station 510 and the relay device 530 from the time t when the signal is transmitted from the base station 510. The sum of the propagation delay time corresponding to the distance between the propagation delay time corresponding to the distance between the relay device 530 and the terminal 520 and the processing delay time (N) for the relay at the relay device 530 is added together. After the arrival at the terminal 520.

In this case, when the multipath fading according to the surrounding environment is very small and the signal received by the relay device 530 is transmitted to the terminal 520 after the processing delay time N passes, the second path The signal transmitted through path2 arrives at the terminal 520 such that a starting point is included in a CP period when one OFDM symbol is considered as a reference unit. Here, the radius of the relay device 530 is configured in consideration of the length of the CP so as to satisfy the equation (1) as described above.

Meanwhile, the signals transmitted through the first path path1 and the second path path2 arrive at the terminal 520 with a difference of the processing time N of the relay device 530. In consideration of the difference between the signals arriving through the base station 510 may determine the signal transmission time.

For example, in order for the signals transmitted through the first path path1 and the second path path2 to arrive at the terminal 520 simultaneously (or to arrive within a CP section), the base station 510 is After the signal is first transmitted through the second path path2, and after the processing delay time N of the relay device 530 passes, the same signal is transmitted through the first path path1 to the terminal 520. The signals transmitted through the path1 and the second path2 may arrive at the same time. Here, time N may mean N TTI in a system for transmitting a signal in units of Transmission Time Interval (TTI), such as LTE or LTE-Advanced system, and the unit of TTI may be a predetermined predetermined time (for example, , 1ms).

In addition, the relay device 530 relays a signal in consideration of a propagation delay time corresponding to the distance between the relay device 530 and the terminal 520 when the signal received from the base station 510 is relayed to the terminal 520. You can consider the time point.

For example, as shown in FIG. 5, when the propagation delay time according to the distance between the relay device 530 and the terminal 520 is 360 ns, the relay device 530 transmits the time transmitted by the base station 510 at time t. The signal is received at t + 3.3us after 3.3us passes, and the signal is processed at a point in time at which the processing delay time N according to the processing of the received signal is α (e.g., α = 360ns) earlier than the time point t + N + 1. May be transmitted to the terminal 520.

When the transmission time is determined in consideration of the propagation path delay time of the transmission path as described above, the base station 510 is connected to the terminal (530) to the final relay device 530 constituting the path having the longer propagation delay time of two paths. Signaling may be provided to advance the transmission time point (or relay time point) to 520, and the final relay device 530 may determine the transmission time point of the signal based on the transmission time information received from the base station 510. For example, by as fast as N TTI-α, the probability that the signal received by the terminal 520 through all the paths is included in the CP period may be increased.

FIG. 6 is a conceptual view illustrating a cooperative communication method according to another embodiment of the present invention, in which a terminal 640 is located in different beam regions of a base station 610, and a first relay device 620 and a second relay device, respectively. An example of receiving a signal through 630 is illustrated.

As shown in FIG. 6, the first relay device 620 and the second relay device 630 are located in the first beam 611 region and the second beam 613 region of the base station 610, respectively, and the terminal 640. ) Is located at the boundary area of the service area of the first relay device 620 and the second relay device 630, the terminal 640 may include a first path and a second relay including the first relay device 620. The signal may be received via a second path including the device 630.

Referring to FIG. 6, the signal transmitted from the base station 610 first arrives at the first relay device 620 located on the first path and the second relay device 630 located on the second path, and then the first relay. The device 620 and the second relay device 630 are delayed by the processing delay time N for the signal relay, respectively, and arrive at the terminal 640 within the CP period.

Here, since the terminal 640 is located in the service area of the first relay device 620 and the service area of the second relay device 630, the time delay difference between the first path and the second path is included in the CP section.

If the total delay time of the first path via the first relay device 620 is T1a + T1b, and the total delay time of the second path via the second relay device 630 is T2a + T2b, As shown in Fig. 2, when the difference between the delay time between the first path and the second path is within 2 × T _R , where T _R means the propagation delay time corresponding to the relay distance R, the first path and the second path. The signal transmitted through the path arrives at the terminal 640 within the CP section.

On the other hand, when there are two or more relay devices for relaying signals transmitted from the base station, the delay time between the relay devices is further added, so that the UE receives signals transmitted through different paths within the CP section as shown in FIG. 6. You may not be able to.

7 is a conceptual diagram illustrating a cooperative communication method according to another embodiment of the present invention. For example, when a terminal receives signals through two different paths, each path is configured with two relay devices. It is shown.

Referring to FIG. 7, the signal transmitted through the first beam 711 from the base station 710 is received by the first relay device 721 located in the area of the first beam 711 and receives the second relay device 723. ), And the second relay device 723 transmits a signal received from the first relay device 721 to the terminal 750.

In addition, the signal transmitted from the base station 710 via the second beam 713 is received by the third relay device 731 located in the region of the second beam 713 and transmitted to the fourth relay device 733. The fourth relay device 733 transmits a signal received from the third relay device 731 to the terminal 750.

That is, the terminal 750 has a first path from the base station 710 via the first relay device 721 and the second relay device 723, and the third relay device 731 and fourth from the base station 710. A signal is received via a second path via the relay device 733. Here, the same data may be transmitted through the first path and the second path, or different data may be transmitted.

As shown in FIG. 7, when each path from the base station 710 to the terminal 750 includes two relay devices, signals received by the terminal 750 may not be included in the CP section. In setting the path, the path 710 must set a multi-path to the terminal 750 in consideration of the distance to the final relay device included in each path.

In the cooperative communication environment as shown in FIG. 7, when the first path and the second path from the base station 710 to the terminal 750 satisfy Equation 3, signals transmitted through the first path and the second path. The arrival time of the terminal 750 is included in the CP section.

Accordingly, the base station 710 sets the multi-path by selecting relay devices to relay a signal to the terminal 750 in consideration of the final delay time of each path by using the distance information of the relay devices included in each path. . Here, in consideration of the terminal 750, when the maximum distance at which the signal is relayed is R, the signal received from the terminal 750 may be included in the CP section when the difference in the distance of each path is within R.

As described above, in order for the base station to transmit a signal using a multipath, a base station or a beam to be used for transmitting a signal to the terminal or the corresponding relay device must be selected. To this end, the base station may use a method of setting a path from the base station to the relay device or the terminal by using the location information of the terminal. The beam information of the base station may be transmitted to the base station, and the base station may set a transmission path based on the information of the neighboring base station, the neighboring relay device information, or the beam information of the base station received from the terminal.

On the other hand, when the terminal requests data transmission to the base station, and the base station determines to transmit data using the multi-beams corresponding to the data transmission request received from the terminal, the base station uses the multi-beam transmission information and / Alternatively, the transmission path information may be notified to the terminal. Here, the multi-beam transmission information and / or transmission path information may be provided to the terminal through various paths. For example, the base station may transmit multi-beam transmission information and / or transmission path information to the terminal using a preset primary path.

When the base station transmits data using the multipath to the terminal, each relay device included in the multipath transmits data to its scheduler at a preset transmission time (or relay time) to support data transmission through the multipath. It transmits the data received from the base station or another relay device without performing the transmission.

That is, even when each relay device has an independent scheduler, at the time of cooperative communication through the multipath, radio resources for supporting transmission through the multipath are preferentially allocated, and signals are allocated using the allocated radio resources. By relaying, the terminal can receive a signal through a multi-path at a certain point in time.

Meanwhile, the terminal processes data received through the plurality of beams based on the multi-beam transmission information and / or transmission path information received by the base station.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

110: first transmission device 111: first beam
130: second transmission device 131: second beam
150: terminal 200: receiving device
210: antenna 220: OFDM demodulator
221: first channel measuring unit 222: second channel measuring unit
231: first beamforming receiver 232: second beamforming receiver
240: interference canceling unit 250: decoding unit
261: first transport block 262: second transport block
300: receiver 310: antenna
320: OFDM demodulator 330: Channel measuring unit
340: combining unit 350: decoding unit
360: transmission block 410: base station
411, 413, 421, 423, 433, 441, 443: relay device
415, 417, 425, 431, 445: terminal
510: base station 511: first beam
513: second beam 520: terminal
530: relay device 610: base station
611: first beam 613: second beam
620: first relay device 630: second relay device
640: terminal 710: base station
711: first beam 713: second beam
721: first relay device 723: second relay device
731: third relay device 733: fourth relay device
750: terminal

Claims (1)

In the cooperative communication method performed in the transmitting device,
Determining at least one signal transmission path including at least one relay device in consideration of a location of a terminal and a signal propagation delay time of each relay device; And
And transmitting a signal to a terminal using the determined at least one signal transmission path.

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