Excavating
Patent
1997-02-14
1998-05-19
Nguyen, Hoa T.
Excavating
370248, 370249, 455115, 4552261, 455 674, G01R 3128, H03C 162, H04B 1700
Patent
active
057545600
DESCRIPTION:
BRIEF SUMMARY
This application is the national phase of international application PCT/FI96/00347, filed Jun. 11, 1996 which designated the U.S.
The present invention relates to the monitoring of radio transceivers, in particular at base stations of mobile communications systems.
FIGS. 1 and 2 show a prior art solution for connecting test apparatus with a base station. The base station l, which has connection with a base station controller 2, comprises at least the following functional blocks: operation and maintenance 3, a frame unit 4, a transceiver unit 5, a combiner 6 and a receiving. multicoupler 7.
The essential part from the point of view of the invention is the test apparatus 8, which is used to measure the condition of the base station. In FIG. 1, the test apparatus 8 is connected with cables to combiner 6 and receiving multicoupler 7. FIG. 2 shows an arrangement in which the test apparatus 8 is provided with a dedicated antenna and is thus not connected with cables to transmitting and receiving branches, but measures the air interface.
Drawbacks of separate test apparatus include the large number of connections, which impairs the reliability and measuring accuracy and adds to the cost of the system. Furthermore, the prior art approaches are not versatile, i.e. the test signal is either directly connected, as in FIG. 1, or passes through antennas as in FIG. 2. However, with the known approaches one cannot variably select both directly coupled signals and signals transmitted via antennas for measurement.
In connection with TDMA mobile communications systems, such as the GSM and DCS1800 systems, separate test apparatus simulates the passing of the signal from the base station to the mobile station and back. For this reason, it has a delay loop installed therein, which will delay the passage of the signal by three TDMA time slots. On account of this delay loop, for instance, the prior art test apparatus is expensive and complex.
The invention relates to test apparatus, to its installation at a base station and to a method of use with which the problems with the prior art are solved and an inexpensive yet versatile and reliable approach is provided for monitoring the operation of a transceiver unit and antennas.
The object of the invention is achieved in such a way that the test apparatus is integrated into the transceiver, and hence it has access to the internal signals within the transceiver and also to external signals arriving via antennas.
The invention will be explained in greater detail in the following by means of figures in which
FIG. 1 shows a prior art arrangement in which test signals are connected directly to the test apparatus,
FIG. 2 shows a prior art arrangement in which test signals are connected through antennas to the test apparatus,
FIG. 3 shows the connection of test apparatus with a transceiver unit in accordance with the invention,
FIG. 4 is a detailed block diagram of the test apparatus of the invention, and
FIGS. 5 and 6 are extensions of FIG. 4 in cases where there are more than two receiving branches.
The arrangement for the test apparatus in accordance with the invention is shown in FIG. 3. The invention will be explained in the context of a base station for a mobile communications system furnished with downlink and uplink diversity properties, but it is obvious that the invention is applicable to transceiver units of other types as well. The transceiver functions of the base station shown in FIG. 3 are duplicated. Redundancy of the system enables downlink and uplink diversity to be achieved. It is possibly attempted at some base stations to improve the diversity properties by installing more than two receiving branches in the base station. To start with, it will be assumed for clarity that there are two transmission branches and two receiving branches. The alterations required by more than two receiving branches will be explained hereinbelow in connection with FIGS. 5 and 6.
In the downlink direction, the signal travel path includes a transmitter TX (not shown), an isolator 10, a directi
Nousiainen Seppo
Pudas Ismo
Nguyen Hoa T.
Nokia Telecommunications Oy
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