WO2008108528A1 - Wireless repeater apparatus for canceling interference signal - Google Patents
Wireless repeater apparatus for canceling interference signal Download PDFInfo
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- WO2008108528A1 WO2008108528A1 PCT/KR2007/005960 KR2007005960W WO2008108528A1 WO 2008108528 A1 WO2008108528 A1 WO 2008108528A1 KR 2007005960 W KR2007005960 W KR 2007005960W WO 2008108528 A1 WO2008108528 A1 WO 2008108528A1
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- Prior art keywords
- signal
- interference
- repetition
- interference cancellation
- received
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/155—Ground-based stations
- H04B7/15564—Relay station antennae loop interference reduction
- H04B7/15585—Relay station antennae loop interference reduction by interference cancellation
Definitions
- the present invention relates to a wireless repeater apparatus for canceling an interference signal, a method for the wireless repeater apparatus, and a computer-readable recording medium storing a program for realizing the method; and, more particularly, to a micro integrated wireless repeater apparatus for canceling an interference signal by using a digital interference canceller and an analog interference canceller (e.g., an RF interference canceller) in an organic manner, a method for the wireless repeater apparatus, and a computer- readable recording medium storing a program for realizing the method.
- a digital interference canceller and an analog interference canceller e.g., an RF interference canceller
- a wireless repeater apparatus used in a mobile communication system is installed in a transmission section in order to service a high-quality signal to a mobile communication terminal located in a shadow area. Since transmit/receive (TX/RX) antennas of the wireless repeater apparatus are installed adjacent to each other, some of signals transmitted through the TX antenna are inversely received through the RX antenna, which greatly affects the quality of a signal to be repeated. Therefore, a variety of technologies have been developed to cancel an interference signal received inversely as above. Examples of such technologies will be described with reference to Figs. 1 and 2.
- Fig. 1 is a block diagram of a conventional wireless repeater apparatus using a general analog interference canceller.
- a conventional wireless repeater apparatus using a general analog interference canceller includes: a donor antenna 100 for receiving a forward repetition signal (i.e., a signal to be repeated in a forward direction) from a base station; a donor band-pass filter 101 for band-pass filtering the forward repetition signal received through the donor antenna 100; an RF interference cancellation signal generator 105 for generating an interference cancellation signal using a forward repetition signal divided by a divider 104; a synthesizer (i.e., an interference signal canceller) 102 for removing an interference signal from a forward repetition signal received from the donor band-pass filter 101 by using the interference cancellation signal generated by the RF interference cancellation signal generator 105; a repetition amplifier 103 for amplifying a forward repetition signal received from the synthesizer 102; the divider 104 for dividing the amplified forward repetition signal received from the repetition amplifier 103 and transmitting the divided signals to the RF interference cancellation signal generator 105 and a service band-pass filter 106; the service band-pass filter
- the RF interference cancellation signal generator 105 generates an interference cancellation signal by using a forward repetition signal received from the divider 104, and transmits the generated interference cancellation signal to the synthesizer 102. Then, the synthesizer 102 removes an interference signal from a forward repetition signal received from the donor band-pass filter 101 by using the interference cancellation signal received from the RF interference cancellation signal generator 105.
- the above-described conventional method can cancel an interference signaL.
- the hardware implementation complexity becomes very high, thus making it impossible to implement the above- described conventional method.
- Fig. 2 is a block diagram of a conventional wireless repeater apparatus using a general digital interference canceller.
- a conventional wireless repeater apparatus using a general digital interference canceller includes: a donor antenna 200 for receiving a forward repetition signal (i.e., a signal to be repeated in a forward direction) from a base station; a donor band-pass filter 201 for band-pass filtering the forward repetition signal received through the donor antenna 200; a down-converter 202 for converting a forward repetition signal received from the donor band-pass filter 201 into a baseband signal; a digital converter 203 for converting a forward repetition signal received from the down- converter 202 into a digital signal; a digital interference canceller 204 for removing an interference signal from a forward repetition signal received from the digital converter 203; an analog converter 205 for converting a forward repetition signal received from the digital interference canceller 204 into an analog signal; an up-converter 206 for converting a forward repetition signal received from the analog converter 205 into an analog signal; an up
- a forward repetition signal i.e., a repetition target signal
- an interference signal which is a feedback of a portion of a signal transmitted through the service antenna 208
- the digital converter 203 converts a forward repetition signal (i.e., a repetition target signal containing an interference signal) down-converted by the down-converter 202 into a digital signal, and transmits the digital signal to the digital interference canceller 204.
- the digital interference canceller 204 detects a feedback signal and cancels an interference signal contained in a forward repetition signal to achieve a gain.
- the above-described conventional digital interference cancellation method can cancel an interference signal regardless of the delay time of a fed-back interference.
- the conventional digital interference cancellation method degrades in interference cancellation performance and thus has a limitation in the interference cancellation performance.
- the micro wireless repeater apparatus has a very small distance between a donor antenna and a service antenna, a direct feedback signal becomes very strong. Therefore, the conventional digital interference canceller fails to process a strong interference signal, thus making it impossible to achieve a large interference cancellation gain.
- An embodiment of the present invention is directed to providing a micro integrated wireless repeater apparatus for canceling an interference signal by using a digital interference canceller and an analog interference canceller (e.g., an RF 1 interference canceller) in an organic manner, a method for the wireless repeater apparatus, and a computer-readable recording medium storing a program for realizing the method.
- a digital interference canceller and an analog interference canceller e.g., an RF 1 interference canceller
- Another embodiment of the present invention is directed to providing a micro integrated wireless repeater apparatus for canceling an interference signal, which can increase the stability of signal repetition and enhance the signal quality by removing a feedback signal component from a repetition target signal by using a digital interference canceller and an analog interference canceller (e.g., an RF interference canceller) in an organic manner, a method for the wireless repeater apparatus, and a computer-readable recording medium storing a program for realizing the method.
- a micro integrated wireless repeater apparatus for canceling an interference signal which can increase the stability of signal repetition and enhance the signal quality by removing a feedback signal component from a repetition target signal by using a digital interference canceller and an analog interference canceller (e.g., an RF interference canceller) in an organic manner
- a method for the wireless repeater apparatus and a computer-readable recording medium storing a program for realizing the method.
- a further embodiment of the present invention is directed to providing a micro integrated wireless repeater apparatus for canceling an interference signal where a donor antenna must be physically close to a service antenna, which can achieve a large interference cancellation gain, increase the stability of signal repetition and enhance the signal quality by getting a digital interference canceller to remove a residual interference signal component after getting an analog interference canceller (e.g., an RF interference canceller) to remove an interference signal component, which has a short time delay and a high interference level (i.e., a strong signal interference) in an RF domain, according to a control signal received from the digital interference canceller, a method for the wireless repeater apparatus, and a computer-readable recording medium storing a program for realizing the method.
- an analog interference canceller e.g., an RF interference canceller
- a micro integrated wireless repeater apparatus for canceling an interference signal, including: a receiving means for receiving a repetition signal; an analog interference cancellation means for generating an interference cancellation signal according to a control signal and removing an interference signal from the repetition signal received from the receiving means; a digital interference cancellation means for canceling a residual interference signal remaining in a repetition signal obtained by canceling an interference signal component by the analog interference cancellation means; a control means for controlling the analog interference cancellation means by transmitting the control signal to the analog interference cancellation means according to control information received from the digital interference cancellation means; and a transmitting means for transmitting a repetition signal obtained by canceling a residual interference signal component by the digital interference cancellation means.
- a micro integrated wireless repeater apparatus for canceling an interference signal in which a donor antenna must be physically close to a service antenna, can increase the stability of signal repetition and enhance the signal quality by removing a feedback signal component from a repetition target signal by using a digital interference canceller and an analog interference canceller (e.g., an RF interference canceller) in an organic manner.
- a digital interference canceller and an analog interference canceller e.g., an RF interference canceller
- a micro integrated wireless repeater apparatus for canceling an interference signal in which a donor antenna must be physically close to a service antenna, can achieve a large interference cancellation gain, increase the stability of signal repetition and enhance the signal quality by getting a digital interference canceller to remove a residual interference signal component after getting an analog interference canceller (e.g., an RF interference canceller) to remove an interference signal component which has a short time delay and a high interference level (i.e., a strong signal interference) in an RF domain, according to a control signal received from the digital interference canceller .
- an analog interference canceller e.g., an RF interference canceller
- Fig. 1 is a block diagram of a conventional wireless repeater apparatus using a general analog interference canceller.
- Fig. 2 is a block diagram of a conventional wireless repeater apparatus using a general digital interference canceller.
- Fig. 3 is a block diagram of a micro integrated wireless repeater apparatus for canceling an interference signal in accordance with an embodiment of the present invention.
- Fig. 4 is a block diagram of a digital interference canceling unit of Fig. 3 in accordance with an embodiment of the present invention.
- Fig. 5 is a block diagram of an RF interference cancellation signal generator of Fig. 3 in accordance with an embodiment of the present invention.
- Fig. 6 is a flow diagram illustrating a wireless repeating method for canceling an interference signal in accordance with an embodiment of the present invention.
- Fig. 3 is a block diagram of a micro integrated wireless repeater apparatus for canceling an interference signal in accordance with an embodiment of the present invention.
- a micro integrated wireless repeater apparatus for canceling an interference signal in accordance with the present invention includes: a receiving terminal 310 for receiving a forward repetition signal (i.e., a signal to be repeated in a forward direction); an analog interference canceller (i.e., an RF interference canceller) 320 for generating an interference cancellation signal according to a control signal received from an RF controller 340 and removing an interference signal from a forward repetition signal received from the receiving terminal 310; a digital interference canceller 330 for canceling a residual interference signal remaining in a forward repetition signal obtained by canceling an interference signal component by the analog interference canceller 320; the RF controller 340 for controlling the analog interference canceller 320 according to control information received from the digital interference canceller 330; and a transmitting terminal 350 for transmitting a forward repetition signal obtained by canceling a residual interference signal component by the digital interference canceller 330.
- a forward repetition signal i.e., a signal to be repeated in a forward direction
- an analog interference canceller i.e.
- the analog interference canceller 320 primarily cancels an interference signal component, which has a short time delay (e.g., 300 ns or less) and a high interference level (e.g., an interference level about 20 dB higher than a primary signal to be repeated when the repeater apparatus has the maximum gain) in an RF domain, according to a control signal received from the digital interference canceller 330 through the RF controller 340, and then the digital interference canceller 330 detects a feedback signal and secondarily cancels a residual interference signal component contained in a forward repetition signal.
- the receiving terminal 310 includes a donor antenna 311 and a donor band-pass filter 312.
- the analog interference canceller 320 includes a divider 321, an RF interference cancellation signal generator 322, and a synthesizer 323.
- the digital interference canceller 330 includes a down-converter 331, a digital converter 332, a digital interference canceling unit 333, an analog converter 334, and an up-converter 335.
- the transmitting terminal 350 includes a service band-pass filter 351 and a service antenna 352.
- the micro integrated wireless repeater apparatus for canceling an interference signal in accordance with the present invention includes: a donor antenna 311 for receiving a forward repetition signal (i.e., a signal to be repeated in a forward direction) from a base station; a donor band-pass filter 312 for band-pass filtering the forward repetition signal received through the donor antenna 311; an RF interference cancellation signal generator 322 for generating an interference cancellation signal using a forward repetition signal received from the divider 321; a synthesizer (i.e., an interference signal canceller) 323 for removing an interference signal from a forward repetition signaL received from the donor band-pass filter 312 by using the interference cancellation signal received from the RF interference cancellation signal generator 322; a down-converter 331 for converting a forward repetition signal received from the synthesizer 323 into a baseband signal; a digital converter 332 for converting a forward repetition signal received from the down-converter 331 into a digital signal; a digital interference canceling unit 333 for removing
- the RF controller 340 receives the control information for controlling the RF interference cancellation signal generator 322 from the digital interference canceling unit 333, which will be described later with reference to Fig. 4.
- One of the forward repetition signals divided by the divider 321 is transmitted to the RF interference cancellation signal generator 322 and is used to generate the RF interference cancellation signal, while the other of the divided forward repetition signals is transmitted to the service band-pass filter 351 and is repeated.
- Fig. 4 is a block diagram of the digital interference canceling unit 333 of Fig. 3 in accordance with an embodiment of the present invention.
- the digital interference canceling unit 333 of the present invention includes: an automatic gain controller 405 for automatically controlling the gain (i.e., the output signal size) of a forward repetition signal to be repeated; a feedback signal detector 402 for detecting the phase, size (amplitude), time delay of a residual feedback signal contained in the forward repetition signal from a baseband digital forward repetition signal received from the automatic gain controller 405 and a baseband digital forward repetition signal received from the digital converter 332, and updating the phase, size (amplitude) and time delay of the feedback signal; an inverse feedback signal synthesizer 403 for generating an inverse feedback signal to be used to cancel the residual feedback signal contained in the forward repetition signal by using the baseband digital forward repetition signal received from the automatic gain controller 405 and the phase, size (amplitude) and time delay of the feedback signal received from the feedback signal detector 402; a feedback signal canceller 404 for canceling the residual feedback signal contained in the digital forward repetition signal received from the digital converter 332 by using the inverse feedback signal received from the inverse feedback signal
- the synchronization acquirer 400 is essential to, for example, a TDD wireless repeater apparatus and is used to extract a synchronization signal necessary for accurately controlling a signal flow in a forward direction (from base station to mobile communication terminal) or in a reverse direction (from mobile communication terminal to base station) .
- This synchronization signal extraction (or acquisition) process is performed to detect a signal (i.e., a preamble) located at the start of a downlink from the base station to the mobile communication terminal.
- the preamble is configured to efficiently extract a synchronization signal in a TDD scheme, and base station information such as an ID of the base station and segment information can be additionally acquired in an acquisition process for the synchronization signal.
- the synchronization acquirer 400 acquires the synchronization signal, detects the base station information, and transmits the information to the controller 401. Then, the controller 401 controls a TDD- based wireless repeating operation by using the base station information and the synchronization signal received from the synchronization acquirer 400.
- the synchronization acquirer 400 acquires a synchronization signal stably for more than a predetermined time period (e.g., more than about 3 seconds that is a time period that can be regarded as the same signal strength over a plurality of frames) under the condition of more than a predetermined signal size (e.g., more than about 1/10 of an average input signal size) , it applies the synchronization signal to the controller 401.
- a predetermined time period e.g., more than about 3 seconds that is a time period that can be regarded as the same signal strength over a plurality of frames
- a predetermined signal size e.g., more than about 1/10 of an average input signal size
- the synchronization acquirer 400 controls the downlink in consideration of a signal processing time period spent in the respective components 401 to 405 and a time period spent in the filters and other components.
- the feedback signal detector 402 may estimate a feedback signal component by using the base station ID acquired by the synchronization acquirer 400. That is, since the base station ID is constructed using a pseudo noise (PN) code, the phase, size (amplitude) and time delay of the feedback signal may be estimated by calculating the correlation between the base station ID and the forward repetition signal.
- PN pseudo noise
- the feedback signal detector 402 detects the phase, size (amplitude) and time delay of the residual feedback signal contained in the forward repetition signal by calculating the correlation between the base station ID received from the controller 401 and the forward repetition signal received from the automatic gain controller 405 and the digital converter 332, and transmits the detected information to the inverse feedback signal synthesizer 403.
- the automatic gain controller 405 determines a gain value by using the size of the forward repetition signal received from the feedback signal canceller 404, a gain control value according to the current state, a target gain value, and a predetermined target output size value received from the controller 401, and uses the determined gain value to automatically control the gain
- the automatic gain control is performed as follows: When the output value is greater than the predetermined target output size value, the automatic gain controller 405 limits the output size in order not to increase the gain any more. On the other hand, when the output value is smaller than the predetermined target output size value, the automatic gain controller 405 increases the gain by a predetermined unit time (e.g., 3 dB/1 second) until the size of the signal received from the feedback signal canceller 404 reaches the target gain value.
- a predetermined unit time e.g., 3 dB/1 second
- the feedback signal canceller 404 removes a feedback signal from the forward repetition signal received from the digital converter 332 by using the inverse feedback signal received from the inverse feedback signal synthesizer 403, and transmits the resulting signal to the automatic gain controller 405.
- the feedback signal canceller 404 cancels the residual feedback signal contained in the forward repetition signal by synthesizing the forward repetition signal received from the digital converter 332 and the inverse feedback signal received from the inverse feedback signal synthesizer 403, and then transmits the resulting forward repetition signal to the automatic gain controller 405.
- the inverse feedback signal synthesizer 403 controls the phase, size (amplitude) and time delay of the signal used for canceling the feedback signal contained in the forward repetition signal, thereby generating the inverse feedback signal.
- the controller 401 uses the synchronization signal received from the synchronization acquirer 400 to detect the timing of the downlink to control a signal flow from the base station to the mobile communication terminal. Also, using the base station information received from the synchronization acquirer 400, the controller 401 transmits a code (e.g., the base station ID) necessary for detection of the feedback signal to the feedback signal detector 402.
- a code e.g., the base station ID
- the feedback signal detector 402 updates the phase, size (amplitude) and time delay of the feedback signal and then transmits the corresponding update control information to the controller 401.
- the controller 401 transmits control information such as the updated phase, size (amplitude) and time delay to the RF controller 340 so that the RF controller 340 can control the update elements of the RF interference cancellation signal generator 322.
- the controller 401 controls the operations of the automatic gain controller 405, the feedback signal detector 402, the inverse feedback signal synthesizer 403, and the feedback signal canceller 404.
- the controller 402 normally operates the automatic gain controller 405, the feedback signal detector 402, the inverse feedback signal synthesizer 403, and the feedback signal canceller 404.
- the target output size value is preset to a predetermined value and is transmitted to the automatic gain controller 405.
- the controller 401 stops the operations of the automatic gain controller 405, the feedback signal detector 402, the inverse feedback signal synthesizer 403, and the feedback signal canceller 404.
- the digital interference canceling unit 333 further includes an automatic delay controller 406 for preventing a mutual interference between the feedback signal and a multi-path signal. That is, in order for the feedback signal to be able to be generated when a multi-path signal is not received, the automatic delay controller 406 is connected to the automatic gain controller 405 to control the generation delay of the feedback signal so that the feedback signal can be cancelled under the condition that the multi-path signal and the feedback signal do not overlap each other.
- the wireless repeater apparatus beforehand detects the position of a multi-path component, that is, the time when the multi-path signal is generated.
- Fig. 5 is a block diagram of the RF interference cancellation signal generator 322 of Fig. 3 in accordance with an embodiment of the present invention.
- the RF interference cancellation signal generator 322 of the present invention includes: an attenuator 500 for attenuating, according to a control signal received from the RF controller 340, the level (i.e., strength) of the forward repetition signal containing the feedback interference signal received from the divider 321; a time delayer 501 for controlling (or compensating) the time delay for a forward repetition signal received from the attenuator 500 according to a control signal received from the RF controller 340; and a phase shifter 502 for shifting the phase of a forward repetition signal received from the time delayer 501 according to a control signal received from the RF controller 340.
- the phase-shifted forward repetition signal of the phase shifter 502 is transmitted to the synthesizer 323 in order to cancel an interference signal. Then, the synthesizer 323 synthesizes the interference cancellation signal received from the RF interference cancellation signal generator 322 and the forward repetition signal received from the donor bandpass filter 312, to remove an interference signal from the forward repetition signal containing the feedback interference received from the donor band-pass filter 312.
- the analog interference canceller (RF interference canceller) 320 an interference component having a short time delay is cancelled by the analog interference canceller (RF interference canceller) 320, but the residual interference signal having a long time delay is not cancelled as yet.
- the residual interference signal is cancelled by the digital interference canceller 330.
- Fig. 6 is a flow diagram illustrating a wireless repeating method for canceling an interference signal in accordance with an embodiment of the present invention.
- a forward repetition signal is repeated, and then a feedback signal remaining in a subsequent forward repetition signal is cancelled by using the resulting feedback signal.
- a signal received from the interference canceller 320/330 through a path from the donor antenna 311 to the donor band-pass filter 312 may contain both of a repetition signal that is transmitted from a base station for repeating an actual service and a feedback signal that is a feedback of a signal transmitted through the service antenna 352, or main contain only a feedback signal containing a random noise.
- a base station transmission signal is represented as a multi-path signal due to a wireless channel environment, and the case where there is only a feedback signal in a signal received in the wireless repeater apparatus corresponds to the case where the base station does not transmits a transmission signal to the mobile communication terminal.
- the receiving terminal 310 receives a forward repetition signal that is a signal to be repeated in a forward direction.
- the analog interference canceller (the RF interference canceller) 320 generates an interference cancellation signal according to a control signal received from the RF controller 340, and cancels an interference signal from the forward repetition signal.
- the digital interference canceller 330 cancels a residual interference signal remaining in a forward repetition signal obtained by canceling an interference signal component by the analog interference canceller 320.
- the RF controller 340 controls the analog interference canceller (the RF interference canceller) 320 according to control information received from the digital interference canceller 330.
- the transmitting terminal 350 transmits a forward repetition signal obtained by canceling a residual interference signal component by the digital interference canceller 330.
- analog interference cancellation operation S602, the digital interference cancellation operation S603, and the control operation S604 have been described as being performed in the above order, they may be performed in any other order because they are circulative operations.
- the methods for canceling an interference signal in accordance with the embodiments of the present invention can be realized as a program and stored in a computer-readable recording medium, such as CD-ROM, RAM, ROM, floppy disk, hard disk and magneto-optical disk. Since the process can be easily implemented by those skilled in the art of the present invention, further description will not be provided herein.
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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US12/529,673 US20100118922A1 (en) | 2007-03-06 | 2007-11-23 | Wireless repeater apparatus for canceling interference signal |
JP2009552576A JP4824821B2 (en) | 2007-03-06 | 2007-11-23 | Interference cancellation radio relay apparatus and method |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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KR10-2007-0022060 | 2007-03-06 | ||
KR20070022060 | 2007-03-06 | ||
KR10-2007-0037066 | 2007-04-16 | ||
KR1020070037066A KR100879334B1 (en) | 2007-03-06 | 2007-04-16 | Apparatus and method for canceling interference signal of micro integrated wireless communication repeater |
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PCT/KR2007/005960 WO2008108528A1 (en) | 2007-03-06 | 2007-11-23 | Wireless repeater apparatus for canceling interference signal |
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WO2010123310A2 (en) * | 2009-04-24 | 2010-10-28 | Samsung Electronics Co., Ltd. | Apparatus and method for compensating for phase error in wireless communication system |
JP2011055350A (en) * | 2009-09-03 | 2011-03-17 | Japan Radio Co Ltd | Radio relay device and delay wave canceling method |
US10979131B2 (en) | 2013-08-29 | 2021-04-13 | Kumu Networks, Inc. | Self-interference-cancelled full-duplex relays |
US11637623B2 (en) | 2013-08-29 | 2023-04-25 | Kumu Networks, Inc. | Optically enhanced self-interference cancellation |
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KR20050009467A (en) * | 2003-07-16 | 2005-01-25 | (주)지에스텔레텍 | Repeater for having function of feedback signal cancellation and mathod for removing feedback signal |
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KR20050093087A (en) * | 2004-03-18 | 2005-09-23 | 주식회사 위다스 | Interference cancellation repeater using delay filter of digital signal |
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US6934511B1 (en) * | 1999-07-20 | 2005-08-23 | Andrew Corporation | Integrated repeater |
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WO2010123310A2 (en) * | 2009-04-24 | 2010-10-28 | Samsung Electronics Co., Ltd. | Apparatus and method for compensating for phase error in wireless communication system |
WO2010123310A3 (en) * | 2009-04-24 | 2011-02-03 | Samsung Electronics Co., Ltd. | Apparatus and method for compensating for phase error in wireless communication system |
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JP2011055350A (en) * | 2009-09-03 | 2011-03-17 | Japan Radio Co Ltd | Radio relay device and delay wave canceling method |
US10979131B2 (en) | 2013-08-29 | 2021-04-13 | Kumu Networks, Inc. | Self-interference-cancelled full-duplex relays |
US11637623B2 (en) | 2013-08-29 | 2023-04-25 | Kumu Networks, Inc. | Optically enhanced self-interference cancellation |
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