Apparatus and method for cancelling self-interference signal in rf front end

Patent metadata

Field	Value
Publication number	US-2016119110-A1
Application number	US-201514715293-A
Country	US
Kind code	A1
Filing date	May 18, 2015
Priority date	Oct 22, 2014
Publication date	Apr 28, 2016
Grant date	—

Abstract

The apparatus includes a transmission signal divider for dividing and transmitting a received signal to a transmission antenna and an attenuator, an attenuator for applying a predetermined attenuation factor to the transmitted signal divided to the attenuator, a phase shifter for phase-shifting the signal to which the attenuation factor is applied by a predetermined phase, and a time delayer for time-delaying the phase-shifted signal by a predetermined time.

First claim

What is claimed is:

1 . A method for cancelling a self-interference signal at a radio frequency (RF) front end, the method comprising:
dividing and transmitting a received signal to a transmission antenna and an attenuator; applying a predetermined attenuation factor to a transmitted signal divided to the attenuator; phase-shifting the signal to which the attenuation factor is applied by a predetermined phase; time-delaying the phase-shifted signal by a predetermined time; transmitting the time-delayed signal to a low noise amplifier (LNA) of a receiving end; and transmitting a residual signal to the LNA after subtracting a self-interference signal from a signal received from a receiving antenna.

2 . The method according to claim 1 , wherein the predetermined attenuation factor is a value determined in consideration of influence attenuated during a signal transmitted from the transmission antenna is received to the receiving antenna.

3 . The method according to claim 1 , wherein the predetermined phase is determined in such a way that the sum of the self-interference signal and the time-delayed signal is equal or less than a preset value.

4 . The method according to claim 1 , wherein the predetermined time is a value determined in consideration of time taken until a signal transmitted from the transmission antenna is received to the receiving antenna.

5 . The method according to claim 1 , wherein a signal transmitted to the transmission antenna corresponds to a signal obtained by shifting a signal transmitted to the attenuator by a predetermined phase value.

6 . An apparatus for cancelling a self-interference signal at a radio frequency (RF) front end, the apparatus comprising:
a transmission signal divider for dividing and transmitting a received signal to a transmission antenna and an attenuator; an attenuator for applying a predetermined attenuation factor to a transmitted signal divided to the attenuator; a phase shifter for phase-shifting the signal to which the attenuation factor is applied by a predetermined phase; and a time delayer for time-delaying the phase-shifted signal by predetermined time.

7 . The apparatus according to claim 6 , further comprising:
a receiving signal subtracter for subtracting a self-interference signal from a signal received from a receiving antenna.

8 . The apparatus according to claim 7 , wherein the receiving signal subtracter corresponds to a 90-degree directional coupler.

9 . The apparatus according to claim 6 , wherein the transmission signal divider corresponds to a 90-degree directional coupler.

10 . The apparatus according to claim 6 , wherein the predetermined attenuation factor is a value determined in consideration of influence attenuated during a signal transmitted from the transmission antenna is received to the receiving antenna.

11 . The apparatus according to claim 6 , wherein the predetermined phase is determined in such a way that the sum of the self-interference signal and the time-delayed signal is equal or less than a preset value.

12 . The apparatus according to claim 6 , wherein the predetermined time is a value determined in consideration of time taken until a signal transmitted from the transmission antenna is received to the receiving antenna.

Assignees

• Lg Electronics Inc
• Univ Yonsei Iacf

Inventors

• Kim Jinmin
• Min Byung-Wook
• Lee Donghyun
• Chung Jaehoon
• Noh Kwangseok

Classifications

• H04B1/123

  using adaptive balancing or compensation means (adaptive filter circuits and algorithms H03H) · CPC title

• H04L5/1461 Primary

  Suppression of signals in the return path, i.e. bidirectional control circuits · CPC title

• H04B15/005

  Reducing noise, e.g. humm, from the supply · CPC title