Method for determining the position of a mobile station
AssigneeNokia Corporation
InventorJORMA PALLONEN
Life of this patent
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Abstract
The present invention relates to a base station of a cellular radio system, which base station comprises antenna equipment for receiving signals from a certain mobile station simultaneously by at least two antenna beams directed in different directions, and measuring equipment for measuring the signal levels of the signals received by the respective antenna beans. For determining the position of the mobile station with greater accuracy the base station is provided with calculating means which are responsive to the measuring equipment to determine the direction from the base station to the mobile station by calculating the relations between the signal levels of the signals for the respective beams.
Claims8
A method for determining the position of a mobile station located in the coverage area of a base station in a radio system and for using said information, in which method the base station comprises equipment for receiving signals from the same mobile station simultaneously by at least two antenna beams (A) directed in different directions, and in which method:
- the signal levels (B) of the signals received by the different antenna beams are measured,
- the signal levels of the signals received from the same mobile station by the different antenna beams are compared (C, D, E),
- the direction to the mobile station in relation to the base station is determined on the basis of the relations between the signal levels (F, G, H, I, J) measured for the different antenna beams, and
- the distance from the mobile station to the base station is calculated on the basis of a timing advance (TA), given to the mobile station by the base station and the propagation speed of the radio signals, characterized in that
- said distance and said direction is used for making a handover decision on the basis of the location of the mobile station.
Base station (BTS1) of a radio system, which base station comprises
- antenna equipment (1-4, 6, 7) for receiving signals from a certain mobile station simultaneously by at least two antenna beams (1-4) directed in different directions,
- measuring equipment (8) for measuring the signal levels of the signals received by the different antenna beams,
- equipment for defining a timing advance (TA) for the mobile station (MS) which is in radio connection with the base station to compensate for a time lag caused by the distance between the mobile station and the base station, and
- calculation means (9) which are responsive to the measuring equipment (8) for determining the direction from the base station (BTS1) to the mobile station (MS) on the basis of the relations of the signal levels measured for the different antenna beams (1-4) and which calculation means (9) comprise equipment for calculating the distance between the base station (BTS1) and the mobile station (MS) on the basis of the timing advance (TA) defined for the mobile station and the propagation speed of the radio signals, characterized in that
- said calculation means are adapted to transmit said direction and said distance further in the system in order to be used for making handover decisions.
Dependencies are inferred from the claim text.