The present invention relates to a method and an apparatus for controlling the gain of a variable-gain amplifier provided in each antenna unit in a multi-antenna radio system comprising a plurality of antenna units and a base transceiver station connected via a signal path connecting the plurality of antenna units in series.
PCT/JP03/05612 and PCT/JP03/13731, both unpublished as of the date of filing of this application, disclose a multi-antenna radio system in which a plurality of antenna units are connected to one base transceiver station in order to reduce radio dead zones inside buildings or in underground shopping areas and the like, by utilizing the characteristic that RAKE reception is possible in a CDMA (Code Division Multiple Access) system. At each antenna unit, the received signal is amplified by a variable gain amplifier and converted by an A/D converter into a digital signal. The plurality of antenna units and the base transceiver station are connected in series, the base transceiver station being located at one end (upstream end); in this configuration, the antenna unit located at the other end (downstream end) passes the digital signal of its received signal to its upstream adjacent antenna unit where the digital value of its received signal is added to the digital value of the received signal received from its downstream adjacent antenna unit, and the process is repeated from one antenna unit to the next, the base transceiver station thus receiving the sum of all the received signals. The base transceiver station reconstructs the signal for each channel by performing RAKE combining on the sum of the received signals for each spreading code.
In such a multi-antenna radio system, to make the most of the advantage that an arbitrary number of antenna units can be connected to one base transceiver station, it is desired that the gain of the variable gain amplifier in each antenna unit be automatically controlled so that the power value of the sum of the received signals that the base transceiver station receives will fall within an optimum range even when the number of connected antenna units changes.
Patent document 1: Japanese Unexamined Patent Publication No. 2003-152611
Patent document 1: Japanese Unexamined Patent Publication No. 2001-285158
It is accordingly an object of the present invention to provide a method and apparatus for appropriately controlling amplifier gain for the received signal of each antenna unit in a multi-antenna radio system.
According to the present invention, there is provided, a method of controlling the gain of a received-signal amplifier provided in each of a plurality of antenna units, in a multi-antenna radio system comprising the plurality of antenna units and a base transceiver station that receives the sum of received signals of the plurality of antenna units via a first signal path connecting the antenna units in series, comprising:
receiving, at the base transceiver station, a signal indicating the number of antenna units via a second signal path connecting the antenna units in series;
computing, at the base transceiver station, a target power value for each of the antenna units by dividing a target value for the total power of the received signals by the number of antenna units;
receiving, at each of the antenna units, the target power value via a third signal path connecting the antenna units in series; and
controlling, at each of the antenna units, the gain of the received-signal amplifier so that the power value of the received signal becomes equal to the target power value.
In
On the signal line 16, the signal to which 1 is added by an adder 34 in each AU, as shown in
In each AU, as shown in
With the above control, the power of the received data of each AU is controlled to a value equal to the quotient of the total target output power by the number of AUs. As a result, the sum of the received data that the BTS receives is controlled to an optimum value regardless of the number of AUs; that is, the sum is automatically controlled to an optimum value even when the number of AUs changes during operation.
Instead of calculating the input power to the amplifier 24 and setting the quotient of the target output power by the input power as the gain of the amplifier 24, the output power of the amplifier 24 may be measured and compared with a target value, and the result of the comparison may be fed back to the gain of the amplifier thereby controlling the output power to the target value.
This is a continuation of International Application PCT/JP2004/014385, published in Japanese, with an international filing date of Sep. 30, 2004.
Number | Name | Date | Kind |
---|---|---|---|
3876947 | Giraudon | Apr 1975 | A |
4228436 | DuFort | Oct 1980 | A |
4228544 | Guyton | Oct 1980 | A |
4500883 | Gutleber | Feb 1985 | A |
4872016 | Kress | Oct 1989 | A |
4876548 | Lopez | Oct 1989 | A |
4916460 | Powell | Apr 1990 | A |
4972505 | Isberg | Nov 1990 | A |
6035218 | Oh et al. | Mar 2000 | A |
6366789 | Hildebrand | Apr 2002 | B1 |
7006810 | Winters et al. | Feb 2006 | B1 |
7280848 | Hoppenstein | Oct 2007 | B2 |
7421288 | Funakubo | Sep 2008 | B2 |
7554964 | Bolgiano et al. | Jun 2009 | B2 |
20030162516 | Solum | Aug 2003 | A1 |
20040106387 | Bauman et al. | Jun 2004 | A1 |
20040146013 | Song et al. | Jul 2004 | A1 |
20050136872 | Yoshizawa et al. | Jun 2005 | A1 |
20080081588 | Rofougaran | Apr 2008 | A1 |
Number | Date | Country |
---|---|---|
1167376 | Dec 1997 | CN |
58-39128 | Mar 1983 | JP |
6-164434 | Jun 1994 | JP |
2000-307325 | Nov 2000 | JP |
2001-285158 | Oct 2001 | JP |
2003-152611 | May 2003 | JP |
Number | Date | Country | |
---|---|---|---|
20070161408 A1 | Jul 2007 | US |
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2004/014385 | Sep 2004 | US |
Child | 11702037 | US |