Device and Method for Downlink Gain Compensation As Well As Radio Unit Comprising the Device

Patent metadata

Field	Value
Publication number	US-2022224291-A1
Application number	US-202217712345-A
Country	US
Kind code	A1
Filing date	Apr 4, 2022
Priority date	Aug 15, 2017
Publication date	Jul 14, 2022
Grant date	—

Abstract

Device and method are disclosed for downlink gain compensation at a radio unit. According to an embodiment, the device comprises a pre-distortion circuit, a digital gain adjuster, a gain determiner and a first gain controller. The pre-distortion circuit is configured to generate and apply a pre-distortion to an input signal. The digital gain adjuster is configured to apply an adjustable gain to an output signal from the pre-distortion circuit. The gain determiner is configured to determine a gain difference between a target downlink gain and current downlink gain. The first gain controller is configured to control the digital gain adjuster based on the gain difference. A radio unit comprising the device is also disclosed.

First claim

1 .- 21 . (canceled)

22 . A device for use in a radio unit, RU, the device comprising:
a pre-distortion circuit configured to generate and apply a pre-distortion to an input signal; a digital gain adjuster (GA) configured to apply an adjustable gain to an output signal from the pre-distortion circuit; a gain determiner configured to determine a gain difference between a target downlink gain and current downlink gain; and a first gain controller configured to control the digital GA based on the gain difference.

23 . The device according to claim 22 , wherein the RU comprises:
an analog GA configured to apply an adjustable gain to an output from the digital GA; and a second gain controller configured to perform a preliminary gain adjustment via the analog GA and then trigger the gain determiner to determine the gain difference.

24 . The device according to claim 23 , wherein the first gain controller is further configured to control the analog GA via the second gain controller based on the gain difference.

25 . The device according to claim 23 , wherein the RU comprises:
a power amplifier (PA) configured to amplify an output from the analog GA; and an observation receiver configured to process an output from the PA to feed back an observation signal to the pre-distortion circuit; and wherein the gain difference is determined from: a compensation gain corresponding to current working frequency and temperature; a power difference between the observation signal and the input signal received by the pre-distortion circuit; and residual gain and phase errors obtained from the pre-distortion circuit.

26 . The device according to claim 24 , wherein the first gain controller ( 2028 ) is configured to control the digital GA by:
determining a first adjustment amount of the digital GA based on the gain difference; determining a next gain of the digital GA based on the first adjustment amount and current applied gain of the digital GA; and configuring the next gain to the digital GA.

27 . The device according to claim 26 , wherein the first gain controller is configured to determine the first adjustment amount by:
comparing the gain difference with a preset first adjustment step of the digital GA; when the gain difference is smaller than the first adjustment step, setting the first adjustment amount as the gain difference; and when the gain difference is greater than or equals to the first adjustment step, setting the first adjustment amount as the first adjustment step.

28 . The device according to claim 26 , wherein the first gain controller is configured to determine the next gain by:
comparing a first sum of the first adjustment amount and the current applied gain with an adjustment range of the digital GA; when the first sum is greater than an upper limit of the adjustment range, setting the next gain as a difference between the first adjustment amount and a second adjustment step of the analog GA; when the first sum is within the adjustment range, setting the next gain as the first sum; and when the first sum is smaller than a lower limit of the adjustment range, setting the next gain as a second sum of the first adjustment amount and the second adjustment step.

29 . The device according to claim 28 , wherein the first gain controller is configured to control the analog GA via the second gain controller by:
when the first sum is greater than the upper limit of the adjustment range, setting a second adjustment amount of the analog GA as the second adjustment step; when the first sum is smaller than the lower limit of the adjustment range, setting the second adjustment amount as an opposite value of the second adjustment step; and configuring the second adjustment amount to the analog GA via the second gain controller.

30 . A method implemented at a device for use in a radio unit (RU), wherein the device comprises a pre-distortion circuit configured to generate and apply a pre-distortion to an input signal, and a digital gain adjuster (GA), configured to apply an adjustable gain to an output signal from the pre-distortion circuit, the method comprising:
determining a gain difference between a target downlink gain and current downlink gain; and controlling the digital GA based on the gain difference.

31 . The method according to claim 30 , wherein the RU comprises:
an analog GA configured to apply an adjustable gain to an output from the digital GA; and a second gain controller configured to perform a preliminary gain adjustment via the analog GA; and wherein the gain difference is determined in response to a trigger signal from the second gain controller.

32 . The method according to claim 31 , further comprising:
controlling the analog GA via the second gain controller based on the gain difference.

33 . The method according to claim 31 , wherein the RU comprises:
a power amplifier (PA), configured to amplify an output from the analog GA; and an observation receiver configured to process an output from the PA to feed back an observation signal to the pre-distortion circuit; and wherein the gain difference is determined from: a compensation gain corresponding to current working frequency and temperature; a power difference between the observation signal and the input signal received by the pre-distortion circuit; and residual gain and phase errors obtained from the pre-distortion circuit.

34 . The method according to claim 32 , wherein controlling the digital GA comprises:
determining a first adjustment amount of the digital GA based on the gain difference; determining a next gain of the digital GA based on the first adjustment amount and current applied gain of the digital GA; and configuring the next gain to the digital GA.

35 . The method according to claim 34 , wherein determining the first adjustment amount comprises:
comparing the gain difference with a preset first adjustment step of the digital GA; when the gain difference is smaller than the first adjustment step, setting the first adjustment amount as the gain difference; and when the gain difference is greater than or equals to the first adjustment step, setting the first adjustment amount as the first adjustment step.

36 . The method according to claim 34 , wherein determining the next gain comprises:
comparing a first sum of the first adjustment amount and the current applied gain with an adjustment range of the digital GA; when the first sum is greater than an upper limit of the adjustment range, setting the next gain as a difference between the first adjustment amount and a second adjustment step of the analog GA; when the first sum is within the adjustment range, setting the next gain as the first sum; and when the first sum is smaller than a lower limit of the adjustment range, setting the next gain as a second sum of the first adjustment amount and the second adjustment step.

37 . The method according to claim 36 , wherein controlling the analog GA via the second gain controller comprises:
when the first sum is greater than the upper limit of the adjustment range, setting a second adjustment amount of the analog GA as the second adjustment step; when the first sum is smaller than the lower limit of the adjustment range, setting the second adjustment amount as an opposite value of the second adjustment step; and configuring the second adjustment amount to the analog GA via the second gain controller.

38 . A device for use in a radio unit (RU), the device comprising:
a pre-distortion circuit configur

Assignees

• Ericsson Telefon Ab L M

Inventors

• Liu Peng
• Liu Yahui
• Jie Junfeng
• Wen Gan
• Liu Guangfeng

Classifications

• H03F3/245 Primary

  with semiconductor devices only · CPC title

• H03G2201/103

  being an amplifying element · CPC title

• H03F1/30

  Modifications of amplifiers to reduce influence of variations of temperature or supply voltage {or other physical parameters (in differential amplifiers H03F3/45479)} · CPC title

• H04B1/16

  Circuits · CPC title

• H03F2200/408

  the output amplifying stage of an amplifier comprising three power stages · CPC title