Rf filter suppression tuning based on transmit power

Patent metadata

Field	Value
Publication number	US-2017012597-A1
Application number	US-201514793694-A
Country	US
Kind code	A1
Filing date	Jul 7, 2015
Priority date	Jul 7, 2015
Publication date	Jan 12, 2017
Grant date	—

Abstract

Methods and apparatus, including computer program products, are provided filters. In some example embodiments, there is provided a radio frequency filter including at least one resonant circuit selectable to vary at least the selectivity of the radio frequency filter, wherein the selectivity is varied based on at least one of a first amount of transmit power being used at a user equipment and a second amount of received signal power. Related apparatus, systems, methods, and articles are also described.

First claim

1 . An apparatus comprising:
a radio frequency filter including at least one resonant circuit selectable to vary at least the selectivity of the radio frequency filter, wherein the selectivity is varied based on at least one of a first amount of transmit power being used at a user equipment and a second amount of received signal power.

2 . The apparatus of claim 1 , wherein the at least one resonant circuit is selected to suppress transmit signals in a stopband outside a passband of the radio frequency filter, when the user equipment is in a high power transmission state.

3 . The apparatus of claim 1 , wherein the at least one resonant circuit is not selected, when the user equipment is in a low power transmission state.

4 . The apparatus of claim 1 , wherein the radio frequency filter comprises a tunable radio frequency bandpass filter, a tunable duplex filter, a tunable radio frequency lowpass filter, a tunable radio frequency highpass filter, or any combination thereof.

5 . The apparatus of claim 1 , wherein the radio frequency filter comprises a transmit filter including an output and an input, wherein the output is coupled to an antenna and the input is coupled to a power amplifier.

6 . The apparatus of claim 1 , wherein the radio frequency filter comprises a receive filter including an output and an input, wherein the input is coupled to an antenna and the output is coupled to a low noise amplifier.

7 . The apparatus of claim 1 further comprising:
a controller configured to at least determine the first amount of transmit power and/or the second amount of receive power and select, based on the first amount and second amount, the at least one resonant circuit.

8 . The apparatus of claim 7 , wherein the transmit power is determined from an indication sent by a base station to the user equipment.

9 . The apparatus of claim 7 , wherein the controller selects the at least one resonant circuit by closing a switch.

10 . The apparatus of claim 7 , wherein the controller selects the at least one resonant circuit, when transmission is inhibited and reception is enabled.

11 . The apparatus of claim 7 , wherein the controller selects the at least one resonant circuit based on a comparison of the first amount of transmit power to a plurality of threshold transmit powers, wherein the threshold transmit powers are mapped to a corresponding selectivity required at the radio frequency filter.

12 . The apparatus of claim 1 , wherein the at least one resonant circuit comprises at least one of an inductor, a capacitor, and an acoustic wave filter.

13 . The apparatus of claim 1 , wherein the at least one resonant circuit comprises at least one inductor in series with at least one capacitor.

14 . The apparatus of claim 1 , wherein the at least one resonant circuit comprises at least one inductor in parallel with at least one capacitor.

15 . The apparatus of claim 14 , wherein the least one resonant circuit is coupled in series to at least one coupling capacitor.

16 . The apparatus of claim 15 , wherein the at least one capacitor and the at least one coupling capacitor include at least one variable capacitor under the control of the controller.

17 . The apparatus of claim 1 , wherein the high power transmission state transmits at a higher power than the low power transmit state.

18 . A method comprising:
varying at least a selectivity of a radio frequency filter including at least one resonant circuit by at least selecting the at least one resonator circuit, wherein the selectivity is varied based on at least one of a first amount of transmit power being used at a user equipment including the radio frequency filter and a second amount of received signal power.

19 . The method of claim 18 , wherein the at least one resonant circuit is selected to suppress transmit signals in a stopband outside a passband of the radio frequency filter, when the user equipment is in a high power transmission state.

20 . The method of claim 18 , wherein the at least one resonant circuit is not selected, when the user equipment is in a low power transmission state.

21 - 37 . (canceled)

Assignees

• Nokia Technologies Oy

Inventors

• Piipponen Antti
• Lähteensuo Toni H

Classifications

• H03H7/0115 Primary

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H03H7/0161 Primary

  Bandpass filters (H03H7/12 takes precedence) · CPC title

• H04B1/401

  for selecting or indicating operating mode · CPC title

• H03H7/0153

  Electrical filters; Controlling thereof · CPC title

• H04B1/1036

  with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters (H04B1/123 takes precedence; filter circuits H03H) · CPC title