Telecommunications – Transmitter and receiver at separate stations – Having measuring – testing – or monitoring of system or part
Reexamination Certificate
1999-09-03
2001-10-02
Chang, Vivian (Department: 2745)
Telecommunications
Transmitter and receiver at separate stations
Having measuring, testing, or monitoring of system or part
C455S067150, C455S423000, C455S446000
Reexamination Certificate
active
06298219
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method for the determination of neighbours of a sub-cell in a cellular radio network base station applying dynamic channel allocation, the base station comprising at least two sub-cells; in each sub-cell, an antenna unit with a fixed connection to the base station; at least one transceiver for transmitting a signal through the antenna unit; at least one measurement unit for measuring the reception power of the signal received through the antenna unit.
BACKGROUND OF THE INVENTION
A problem in the above described arrangement is that the system operator manually determines the neighbours of each base station's sub-cells. The neighbours must be determined because a sub-cell and its neighbour cell cannot use one and the same dynamically selected frequency/time slot combination because transmitters occupying the same frequency and time slot would cause too much co-channel interference for each other. In addition, handover between sub-cells becomes difficult if the neighbours are not determined. A manual determination of neighbours requires time-consuming manual measurements of reception powers, performed within the sub-cells. A large number of measurements may be required. When a new sub-cell is added to the system, or the position of a sub-cell antenna unit is changed, manual determination of neighbours will have to be repeated. This makes the system significantly more difficult to optimise and to expand, and increases the operating costs of the system.
BRIEF DESCRIPTION OF THE INVENTION
An object of the invention is thus to provide a method and an equipment implementing the method to allow the above mentioned problems to be solved. This is achieved with a method described in the preamble, characterized in that: a transceiver is used for transmitting a test signal through an antenna unit of a sub-cell under examination; the test signal is received through antenna units of other sub-cells; a measurement unit is used for measuring the reception power of the test signal received through the antenna units of the other sub-cells; on the basis of the measured reception powers of the test signal, neighbour sub-cells of the sub-cell under examination are determined.
The invention also relates to a cellular radio network base station comprising: dynamic channel allocation; at least two sub-cells; in each sub-cell, an antenna unit with a fixed connection to the base station; at least one transceiver for transmitting a signal through an antenna unit; at least one measurement unit for measuring the reception power of the signal received through an antenna unit; a switching field for connecting a signal to travel between a particular transceiver and antenna unit; a control unit controlling the operation. The base station according to the invention is characterized in that: the control unit is arranged to direct the transceiver to transmit a test signal through an antenna unit of the sub-cell under examination connected via the switching field; the antenna units of the other sub-cells are arranged to receive the test signal; the measurement unit is arranged to measure the reception power of the test signal received through the antenna units of the other sub-cells; the control unit is arranged to determine, on the basis of the measured reception powers of the test signal, the neighbour sub-cells of the sub-cell under examination.
The preferred embodiments of the invention are disclosed in the dependent claims.
The invention is based on determining, on the basis of a reception power, those neighbour sub-cells in which a signal transmitted through the sub-cell under examination could cause disturbance. In such case, the reception power of a test signal is high enough in the neighbour sub-cells concerned. The neighbour sub-cells thus found should not use the same frequency/time slot pairs as the sub-cell under examination.
The method and arrangement of the invention provide many advantages. Manual measurements of reception powers are not needed. It is therefore easier and less expensive to add new sub-cells and to change existing sub-cells. The quality of connections improves because sub-cells applying the same frequency/time slot pair and thus causing interference for each other are placed at a sufficiently long distance from each other. The reliability of successful handover is enhanced.
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patent: 5802473 (1998-09-01), Rutledge et al.
patent: 5854981 (1998-12-01), Wallstedt et al.
patent: 5915221 (1999-06-01), Sawyer et al.
patent: 195 37 398 (1997-04-01), None
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patent: 97/18683 (1997-05-01), None
Patronen Petri
Silventoinen Marko
Suhonen Aki
Chang Vivian
Nguyen Duc
Nokia Telecommunications Oy
Pillsbury & Winthrop LLP
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