Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-05-28
2001-07-03
Urban, Edward F. (Department: 2746)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S561000, C342S457000
Reexamination Certificate
active
06256505
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed toward an improved transceiver unit for use in a mobile communication system and, more particularly, toward an improved transceiver unit equipped for time of arrival measurements.
BACKGROUND OF THE INVENTION
Mobile communication systems generally include a plurality of base stations, with each base station covering or servicing a particular geographical area or cell. Each base station is equipped with one to twelve transceiver units, or traffic controllers, which handle uplink and downlink communication traffic with a plurality of mobile subscribers over a plurality of radio channels. For location determination purposes, i.e., approximating the location of a particular mobile subscriber, the base station may also be equipped with a time of arrival measurement unit for measuring the arrival times of burst signals transmitted from the mobile subscriber whose location is to be approximated. The time of arrival measurements may be made on burst signals transmitted from a mobile subscriber within the particular cell serviced by the base station, or also may be made on burst signals transmitted from a mobile subscriber in another cell.
The time of arrival measurements are transmitted from the base stations to a mobile positioning center within the mobile communication system. The mobile positioning center analyzes the time of arrival measurements from various base stations, whose coordinates are known, and determines an approximate range within which the mobile subscriber is located.
Incorporating stand-alone Transceiver Units (TRUs) and Time of Arrival Measurement Receivers (TMRs) into a base station adds to the physical size of the base station. Further, since the base station can simultaneously receive traffic and measurement bursts in parallel on the same channel, additional hardware and signal processing is required to distinguish between the two signals.
The present invention is directed toward overcoming one or more of the above-mentioned problems.
SUMMARY OF THE INVENTION
In a base station for use in a mobile communication system for communication with mobile subscribers over a plurality of radio channels, an improved transceiver is provided including a traffic controller handling downlink and uplink communication traffic with mobile subscribers over the plurality of radio channels, and a measuring device measuring arrival times of burst signals from a mobile subscriber communicating on a select one of the radio channels, or from a mobile subscriber communicating on another transceiver unit, on one of the plurality of radio channels.
In one aspect of the improved transceiver, uplink communication traffic on said one of the plurality of radio channels at the traffic controller is interrupted during burst signal measurement by the measuring device.
In another aspect of the improved transceiver, uplink communication traffic on said one of the plurality of radio channels at the traffic controller is interrupted for approximately 0.4-0.5 seconds for burst signal time of arrival measurement.
In another aspect of the improved transceiver, downlink and uplink communication traffic on said one of the plurality of radio channels is cleared at the traffic controller to allow the measuring device to measure burst signal time of arrival on said one of the plurality of radio channels.
In still another aspect of the improved transceiver, downlink and uplink communication traffic on said one of the plurality of radio channels is switched to another of the plurality of radio channels available for communication traffic at the traffic controller to allow the measuring device to measure burst signal time of arrival on said one of the plurality of radio channels.
A method of determining the location of a mobile subscriber communicating with a serving base station on a select radio channel is provided, the location determining method including the steps of selecting at least three base stations to measure arrival times of burst signals from the mobile subscriber, tuning the at least three base stations to listen to the select radio channel, transmitting a burst signal from the mobile subscriber on the select radio channel, measuring a time of arrival of the burst signal at each of the at least three base stations, and analyzing the time of arrival measurements from the at least three base stations to determine the location of the mobile subscriber.
In one aspect of the location determining method, the at least three base stations include the serving base station and at least two secondary base stations.
In another aspect of the location determining method, the step of tuning the at least three base stations to listen to the select radio channel further includes the step of clearing the select radio channel of communication traffic at each of the at least two secondary base stations.
In another aspect of the location determining method, the step of clearing the select radio channel of communication traffic at each of the at least two secondary base stations includes the step of switching communication traffic on the select radio channel at the at least two secondary base stations to a radio channel different than the select radio channel, with the different radio channel being available for communication traffic.
In another aspect of the location determining method, the step of measuring a time of arrival of the burst signal at each of the at least three base stations includes the steps of interrupting uplink communication traffic on the select radio channel at the at least two secondary base stations, and measuring a time of arrival of the burst signal at each of the at least two secondary base stations during the interruption.
In still another aspect of the location determining method, uplink communication traffic on the select radio channel at the at least two secondary base stations is interrupted for approximately 0.4-0.5 seconds for burst signal time of arrival measurement.
It is an object of the present invention to provide an improved transceiver unit having dual functionality.
It is a further object of the present invention to provide an improved transceiver unit capable of serving the dual purpose of a regular GSM traffic receiver and a time of arrival measurement receiver.
It is a further object of the present invention to provide an improved transceiver unit with reduced hardware costs.
It is yet a further object of the present invention to provide an improved transceiver unit with reduced operation and management processes.
Other aspects, objects and advantages of the present invention can be obtained from a study of the application, the drawings, and the appended claims.
REFERENCES:
patent: 5423067 (1995-06-01), Manabe
patent: 5629710 (1997-05-01), Sawada
patent: 5732354 (1998-03-01), MacDonald
patent: 5854985 (1998-12-01), Sainton et al.
patent: 6021330 (2000-02-01), Vannucci
patent: 0 800 319 (1997-10-01), None
patent: WO 98/15150 (1998-04-01), None
Holmring Anders Thomas
Kingdon Christopher Hugh
Lund Lars-Goran
Zadeh Bagher Rouhollah
Ericsson lnc.
Navarro Arthur I.
Urban Edward F.
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