Method, apparatus, and system for correcting channel of remote radio unit

Patent metadata

Field	Value
Publication number	US-2016197745-A1
Application number	US-201615068502-A
Country	US
Kind code	A1
Filing date	Mar 11, 2016
Priority date	Sep 13, 2013
Publication date	Jul 7, 2016
Grant date	—

Abstract

The present disclosure relates to a remote radio unit (RRU), which is connected to a baseband unit (BBU) and an antenna, comprising: a service transmit channel configured to transmit a first correction signal through the antenna, and a standing wave detecting circuit associated with the service transmit channel, wherein: a working frequency of the standing wave detecting circuit is consistent with the service transmit channel, and the standing wave detecting circuit is capable of detecting a standing wave ratio of the service transmit channel and is configured to receive a correction signal looped back by the antenna, and send the correction signal looped back by the antenna to the BBU, wherein the correction signal looped back by the antenna comprises a portion of the first correction signal reflected by the antenna and is used for a calculation of a correction coefficient of the service transmit channel.

First claim

What is claimed is:

1 . A remote radio unit (RRU), which is connected to a baseband unit (BBU), comprising:
a service transmit channel connected to an antenna, configured to transmit a correction signal through the antenna, wherein the correction signal is received from the BBU; and a standing wave detecting circuit associated with the service transmit channel, wherein: a working frequency of the standing wave detecting circuit is consistent with a working frequency of the service transmit channel; the standing wave detecting circuit is capable of detecting a standing wave ratio of the service transmit channel; and the standing wave detecting circuit is configured to receive a correction signal looped back by the antenna, and send the correction signal looped back by the antenna to the BBU, wherein the correction signal looped back by the antenna comprises a portion of the correction signal reflected by the antenna connected to the service transmit channel and is used for a calculation of a correction coefficient of the service transmit channel.

2 . The RRU according to claim 1 , wherein the RRU comprises:
a first service transmit channel and a second service transmit channel, and the correction signal looped back by the antenna comprises a portion of a correction signal which is transmitted by an antenna connected to the first service transmit channel and then received by an antenna connected to the second service transmit channel.

3 . The RRU according to claim 2 , wherein the standing wave detecting circuit comprises:
a bilateral switch, configured to implement a connection or disconnection between the standing wave detecting circuit and one of the first and second service transmit channels.

4 . A baseband unit BBU, which is connected to a first remote radio unit (RRU), comprising:
a transmitter, configured to send a first correction signal to the first RRU; a receiver, configured to receive a correction signal looped back by an antenna, wherein the correction signal looped back by the antenna comprises a portion of the first correction signal transmitted by a service transmit channel of the first RRU and reflected by the antenna connected to the first RRU; and a processor, configured to calculate a correction coefficient of the service transmit channel according to the correction signal looped back by the antenna.

5 . The BBU according to claim 4 , wherein:
the BBU is further connected to a second RRU, the transmitter is configured to send a second correction signal to the second RRU, and the correction signal looped back by the antenna further comprises a portion of the second correction signal transmitted by a service transmit channel of the second RRU and received by the antenna connected to the first RRU.

6 . The BBU according to claim 4 , wherein:
the transmitter is configured to send a second correction signal to the first RRU, and the correction signal looped back by the antenna comprises a portion of the second correction signal transmitted by a service transmit channel of the first RRU and reflected by the antenna connected to the first RRU.

7 . The BBU according to claim 4 , wherein the processor is configured to:
perform channel estimation on each service transmit channel according to the correction signal looped back by the antenna, to obtain a channel response value of each service transmit channel; obtain a delay difference between each service transmit channel and a reference transmit channel according to the channel response value of each service transmit channel, wherein the reference transmit channel is one service transmit channel of all service transmit channels; and obtain a correction coefficient by using the obtained delay difference, and perform channel compensation on each service transmit channel by using the correction coefficient.

8 . The baseband unit BBU according to claim 7 , wherein the processor is configured to:
obtain a phase difference between each service transmit channel and the reference transmit channel by using the channel response value of each service transmit channel, and obtain the delay difference between each service transmit channel and the reference transmit channel by using the acquired phase difference.

9 . The baseband unit BBU according to claim 7 , wherein the processor is configured to:
transform the channel response value of each service transmit channel to a time domain, and separately obtain a time domain sample point corresponding to a maximum modulus value of the response value of each service transmit channel and use the time domain sample point as a delay of the service transmit channel, so as to obtain the delay difference between each service transmit channel and the reference transmit channel.

10 . A communication system, comprising a baseband unit (BBU) and a first remote radio unit (RRU) connected to the BBU, wherein:
the first RRU is configured to receive a first correction signal from the BBU, transmit the first correction signal through an antenna connected to the first RRU, receive a correction signal looped back by the antenna, and send the correction signal looped back by the antenna to the BBU; wherein the correction signal looped back by the antenna comprises a portion of the first correction signal transmitted by a service transmit channel of the first RRU and reflected by the antenna; and the BBU is configured to send the first correction signal to the first RRU, receive the correction signal looped back by the antenna from the first RRU, and calculate a correction coefficient of the service transmit channel according to the received correction signal looped back by the antenna.

11 . The communication system according to claim 10 , further comprising a second RRU connected to the BBU, wherein:
the BBU is configured to send a second correction signal to the second RRU, the second RRU is configured to receive the second correction signal from the BBU and transmit the first correction signal through an antenna connected to the second RRU, and the correction signal looped back by the antenna comprises a portion of the second correction signal transmitted by a service transmit channel of the second RRU and received by the antenna connected to the first RRU.

12 . The communication system according to claim 10 , wherein:
the BBU is configured to send a second correction signal to the first BBU, and the correction signal looped back by the antenna comprises a portion of the second correction signal transmitted by a service transmit channel of the first RRU and reflected by the antenna connected to the first RRU.

13 . The communication system according to claim 10 , wherein the BBU is configured to:
perform channel estimation on each service transmit channel according to the correction signal looped back by the antenna, to obtain a channel response value of each service transmit channel; obtain a delay difference between each service transmit channel and a reference transmit channel according to the channel response value of each service transmit channel, wherein the reference transmit channel is one service transmit channel of all service transmit channels; and obtain a correction coefficient by using the obtained delay difference, and perform channel compensation on each service transmit channel by using the correction coefficient.

14 . The communication system according to claim 13 , wherein the BBU is configured to:
obtain a phase difference between each service transmit channel and the reference transmit channel by using the channel response value of each service transmit channel, and obtain the delay dif

Assignees

• Huawei Tech Co Ltd

Inventors

• Yi Xiongshu
• Zhang Chaochao
• Guan Lu
• Liu Yun

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04L25/0204 Primary

  of multiple channels · CPC title

• H04L25/0224

  using sounding signals · CPC title

• H04W16/18

  Network planning tools · CPC title

• H04L25/03343

  Arrangements at the transmitter end · CPC title