RF signal repeater, mobile unit position determination system using the RF signal repeater, and method of communication therefor

• US 20020155838A1
• Filed: 06/17/2002
• Published: 10/24/2002
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: John K. Reece, Logan Scott, Randolph L. Durrant
• Inventors: Scott, Logan, Reece, John K., Durrant, Randolph L.
• Granted Patent: US 6,839,539 B2
• Time in Patent Office: Days
• US Class Current: 455/445
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow

Abstract

A RF signal repeater system is added to a wireless communications network which increases user data rates at the periphery of the cellular coverage area by boosting the downlink (base station to mobile user) signal and uplink (mobile user to base station) signal. The RF signal repeater system includes a signal tagging means that adds a unique electronic signature to the repeated signal such that position determination errors due to a non-line of sight propagation path can be corrected. The repeated signal is received and processed with a location measurement unit to determine the time of arrival and to extract the signal tag of the repeated signal. The time of arrival measurement and recovered signal tag are then processed at a mobile location center to determine the true position of the transmitter.

Claims

1. A method of communication, comprising:

providing a base station, a mobile unit, and a signal repeater all located in a cell of a wireless network;

receiving at the signal repeater a signal from at least one of the base station and the mobile unit;

tagging the received signal with an electronic signature identifying the signal repeater; and

transmitting the tagged signal from the signal repeater.

2. The method of claim 1, wherein the receiving at the signal repeater comprises receiving a downlink signal from the base station and the transmitting the tagged signal comprises transmitting a tagged downlink signal to the mobile unit.

3. The method of claim 1, wherein the receiving at the signal repeater steps comprises receiving an uplink signal from the mobile unit and the transmitting the tagged signal step comprises transmitting a tagged uplink to the base station.

4. The method of claim 1, further comprising generating the electronic signature at the signal repeater.

5. An apparatus comprising:

a frequency discriminator to detect unique signal tags in a signal sent from a transmitter, the unique signal tags generated by a signal repeater, to demodulate signal tag, and to generate a repeater tag ID from the signal tag; and

a TOA (time of arrival) receiver to measure a propagation time delay from the transmitter;

the frequency discriminator and TOA receiver coupled to a location center (LC) to determine the position of the mobile unit based on the TOA receiver measurements and the repeater tag ID.

6. The apparatus of claim 5, wherein the transmitter comprises a mobile unit, and the location center comprises a mobile location center (MLC).

7. The apparatus of claim 6, wherein the MLC determines the position of the transmitter based on the TOA receiver measurements and the repeater tag ID by looking up the TOA receiver measurements and the repeater tag ID in a database that includes geographical coordinates of the repeater corresponding to the repeater tag ID and a number of corresponding base stations.

8. A system comprising:

a receiver to receive an electronically tagged signal generated by a signal repeater, the original signal being sent from a transmitter;

a corresponding location management unit coupled to the base station to demodulate the tagged signal, and to generate a repeater tag ID signal therefrom; and

a location center coupled to the location management unit to determine the position of the transmitter based on the TOA receiver measurements and the repeater tag ID.

9. The system of claim 8, wherein the transmitter comprises a mobile unit, and the location center comprises a mobile location center (MLC).

10. The system of claim 9, wherein the mobile location center determines the position of the transmitter based on the TOA receiver measurements and the repeater tag ID by looking up the TOA receiver measurements and the repeater tag ID in a database that includes geographical coordinates of the repeater corresponding to the repeater tag ID and a number of corresponding base stations.