Systems and methods for location determination
Embodiments described by the present disclosure provide improved systems and methods for determining the location of a mobile device. In one embodiment, a system comprises a distributed antenna system (DAS) configured to relay signals to and from the mobile device. Further, the DAS comprises a hub unit; and multiple remote antenna units coupled to the hub unit, wherein signals relayed between the remote antenna units and the hub unit are delayed such that different signal paths between the remote antenna units and the hub unit have different delay times. The system also comprises a base station coupled to the hub unit, wherein the base station receives the signals from the hub unit and determines the delay of signals transmitted between the mobile device and the base station, wherein the system determines the location of the mobile device by using the delay for RF pattern matching.
1. A system for determining the location of a mobile device, the system comprising:
a distributed antenna system configured to relay signals to and from the mobile device, the distributed antenna system comprising:
a hub unit; and
a plurality of remote antenna units coupled to the hub unit, wherein signals relayed between the plurality of remote antenna units and the hub unit are delayed such that at least two signal paths between the plurality of remote antenna units and the hub unit have different delay times; and
a base station coupled to the hub unit, wherein the base station receives the signals from the hub unit and determines the delay of signals transmitted between the mobile device and the base station;
wherein the system is configured to determine the location of the mobile device by using the delay determined by the base station; and
wherein at least some of the signals are delayed by a delay time that has a shorter duration than a maximum allowable delay defined by a communication protocol being used.
2. The system of claim 1 , wherein the delay determined by the base station is used as a parameter in RF pattern matching to determine the location of the mobile device.
3. The system of claim 1 , further comprising a location unit coupled to the base station, wherein the location unit is configured to determine the location of the mobile device based on the delay determined by the base station.
4. The system of claim 3 , wherein the location unit is a part of the base station.
5. The system of claim 1 , wherein the different delay times are configurable.
6. The system of claim 5 , wherein the different delay times are configured by at least one of:
the base station; and
the distributed antenna system.
7. The system of claim 1 , wherein the system is configured to determine the location of the mobile device based on at least one of:
a received signal strength of at least one signal received by the mobile device from at least one alternative base station;
an identification of the at least one alternative base station in communication with the mobile device.
8. The system of claim 1 , wherein the distributed antenna system is configured to physically delay at least some of the signals relayed between the plurality of remote antenna units and the hub unit.
9. The system of claim 1 , wherein the distributed antenna system is configured to digitally delay at least some of the signals relayed between the plurality of remote antenna units and the hub unit.
10. The system of claim 1 , wherein at least some of the plurality of remote antenna units are configured to delay at least some of the signals relayed between the plurality of remote antenna units and the hub unit.
11. The system of claim 10 , wherein the distributed antenna system is configured to digitally delay at least some of the signals relayed between the plurality of remote antenna units and the hub unit in a reconfigurable manner.
12. The system of claim 1 , wherein at least some of the signals are delayed by a delay time that has a longer duration than a minimum resolution as determined by a communication protocol.
13. The system of claim 1 , wherein the hub unit combines the signals received from the plurality of remote antenna units.
14. The system of claim 1 , wherein information regarding the delays is provided by at least one of:
providing information that associates signal power of the signals with the different delay times; and
correlating the signals received through the plurality of remote antenna units.
15. The system of claim 1 , wherein the system is further configured to determine the location of the mobile device by associating signals received from the mobile device with a multipath profile associated with a location.
16. A method for determining a location of a mobile device, the method comprising:
relaying signals between a mobile device and a base station through a plurality of remote antenna units;
delaying the signals relayed between the base station and different remote antenna units in the plurality of remote antenna units by different delay times;
determining a delay of the signals relayed between the base station and the mobile device, wherein the signal is relayed through the plurality of remote antenna units; and
determining the location of the mobile device based on the delay;
wherein at least some of the signals are delayed by a delay time that has a shorter duration than a maximum allowable delay defined by a communication protocol being used.
17. The method of claim 16 , wherein delaying the signals comprises digitally delaying the signals.
18. The method of claim 16 , wherein digitally delaying the signals comprises delaying at least some of the relayed signals in a reconfigurable manner.
19. A distributed antenna system comprising:
a hub unit; and
a plurality of remote antenna units configured to communicate with at least one mobile device, wherein signals relayed between the plurality of remote antenna units and the hub unit along different transmission paths are delayed by different delay times,
wherein the hub unit combines received signals from the plurality of remote antenna units, and transmits the combined signal to a base station system, wherein the base station system determines a delay time for the signals in the combined signal and a location unit determines the location of the at least one mobile device; and
wherein at least some of the signals are delayed by a delay time that has a shorter duration than a maximum allowable delay defined by a communication protocol being used.
20. The system of claim 19 , wherein the hub unit combines the signals using an analog summer.
21. The system of claim 19 , wherein the hub unit combines the signals using a digital summer.
22. The system of claim 19 , wherein the distributed antenna system is configured to digitally delay at least some of the signals relayed between the plurality of remote antenna units and the hub unit in a reconfigurable manner.
23. The system of claim 19 , wherein the location unit is part of the base station system.