Amplifiers – Combined with automatic amplifier disabling switch means
Reexamination Certificate
1998-09-25
2001-05-22
Shingleton, Michael B (Department: 2817)
Amplifiers
Combined with automatic amplifier disabling switch means
C330S150000, C330S151000
Reexamination Certificate
active
06236265
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to radio signal systems. More particularly, the invention relates to an arrangement and a method for preamplifying reception signals for a radio station, particularly for a base station, or respectively, for a radio base station of a mobile radio system, or respectively, of an access network system.
In second generation mobile radio systems, e.g., GSM (Global System for Mobile Communication) see J. Biala,
Mobilfunk and Intelligente Netze
, Viewe Verlag, 1195, particularly pages 57 to 92, as well as presently planned mobile radio systems (UMTS-Universal Mobile Telecommunication System) and in access network systems (see M. Reiss,
Drahtlos zum Freizeichen
, telecom report 18, 1995, pages 34-37), two embodiment types are realized for the design of the reception path for the preamplification of RF reception signals. Thus, in a first embodiment, a preamplifier is integrated into one rack of the base station, usually together with a multicoupling means which distributes the reception signals to a plurality of transceivers. In contrast, in a second embodiment, the preamplifier is positioned as a separate unit in the vicinity of one or more remote antennas and connected via a trunk line to a multicoupling means in the base station.
The first embodiment offers the advantage of a better maintenance opportunity on the basis of the integration in the base station of all the components essential to the processing of the reception signal. The second embodiment has the advantage of guaranteeing a particularly good reception sensitivity of the base station.
In both embodiments, due to the arrangement of the preamplifier upstream of multicoupling means and thus upstream to the transceivers of a base station, a failure of the preamplifier results in a disturbance of the reception at the base station side for the entire radio cell of the base station. Since only a very slight amplification of the reception signals occurs in the multicoupling means, the main burden of the preamplification respectively lies with the preamplifier. This arrangement enables an optimal sensitivity of the reception path, above all given a preamplifier arranged near the antenna, without increasing the demands on the high-level signal behavior of the components connected downstream in the base station. Given a failure of the preamplifier, the sensitivity of the reception path is sharply reduced due to the omission of practically the entire preamplification and to an additional attenuating of the weak reception signals by the trunk line.
Furthermore, failure is particularly critical given a preamplifier positioned near the antenna, since this preamplifier cannot always be reached and accessed easily for maintenance, repair or replacement—as may be the case in winter, given storms, or even at night, for example. Ordinarily the preamplifiers in this embodiment have a means that bridges the amplifier in the event of an error, and thus the reception path is not interrupted. Nevertheless, due to the failing preamplification, the reception path is highly insensitive for the above-mentioned reasons.
The disturbance due to the failure of the preamplifier can be partially compensated for by the use of antenna diversity, since other reception branches of the same or of a neighboring radio cell are seldom jointly affected. However, the service quality of the radio cell is considerably restricted, since qualitative benefits must be foregone due to the antenna diversity.
SUMMARY OF THE INVENTION
It is thus an object of the invention to provide an arrangement and a method which avoid the above-mentioned disadvantages and which secure the preamplification of the reception signals with an optimally low loss of sensitivity of the reception path.
To that end, in an embodiment, the invention provides a circuit for preamplifying signals received by a radio station, comprising:
a) at least one antenna for receiving radio signals;
b) a first preamplifier coupled between the antenna circuit and the radio station, the first preamplifier coupled to the antenna via an antenna feed line, the first preamplifier line coupled to the radio station via a trunk line;
c) a switch coupled to the trunk line, the switch having a control signal input;
d) a second preamplifier coupled to the switch;
e) a bridge line coupled to the switch and across the second preamplifier to effect a bypass of the second preamplifier; and
f) a control signal generator coupled to the switch;
wherein, the control signal generator is effective to generate a control signal to cause the switch to switch radio signals through the bridge line or the second preamplifier.
In an embodiment, the invention provides a method for preamplification of radio signals received by a radio station, comprising the steps of receiving radio signals via at least one antenna unit, preamplifying the radio signals in a first preamplifier which is provided outside of the radio station and is connected to the radio station via a trunk line and to the antenna unit via an antenna feed, usually bypassing a second preamplifier which is provided within the radio station with a bridge line connected in parallel to the second preamplifier, and switching the radio reception signals from the bridge line to the second preamplifier under the control of a controller, given an outage of the first preamplifier.
Thus, in accordance with the invention, a radio station is connected to at least one antenna unit for receiving radio signals. A first preamplifier or preamplifying means is realized outside the radio station and thereto via a trunk line. The first preamplifying means is connected to the antenna unit via an antenna feed and serves for the preamplification of reception signals. A second preamplifier or preamplifying means is provided in the radio station, this second preamplifying means likewise serving for the amplification of the reception signals.
Connected in parallel to the second preamplifying means is a bridge line with which the second preamplifying means is bridged. A changeover means or switch is connected upstream of the bridge line and that second preamplifying means. The changeover means or switch is actuated by a control signal of a control means and switches the reception signals from the bridge line to the second preamplifying means.
By means of the changeover means or switch and the second preamplifying means, the inventive arrangement assures the preamplification of signals in the reception path even given a failure, potential failure or other outage of the first preamplifying means, so that maintenance, repair or replacement can occur at a favorable time for the operator. The sensitivity of the reception path is reduced only by the attenuation of the cable in the trunk line between the first preamplifying means and the radio station.
According to one embodiment of the invention, a bridging switch is provided in the first preamplifying means, this switch bridging the first preamplifying means given an insufficient functioning or failure thereof. It is advantageously assured by this bridging switch that the reception path is not interrupted given a failure of the first preamplifying means.
In order to indicate occurrence of the bridging of the first preamplifying means to the control means in the radio station in this embodiment of the invention, alarm signals can be transmitted to the control means. To that end, in another embodiment of the invention, these alarm signals are transmitted via an alarm message line that leads from the first preamplifying means to the control means. In another embodiment of the invention, the alarm signals are modulated or multiplexed onto the trunk line by a modulator or multiplexor means, then received in a demodulator, or respectively, demultiplexor means in the radio station and transmitted to the control means via a measuring line. In either embodiment, the control means derives the control signal from the alarm signals, this control signal actuating the changeover means for switching the rec
Faerber Michael
Heinz Helmut
Kottkamp Meik
Schiff & Hardin & Waite
Shingleton Michael B
Siemens Aktiengesellschaft
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