APPARATUSES, SYSTEMS, AND METHODS FOR DETERMINING LOCATION OF A MOBILE DEVICE(S) IN A DISTRIBUTED ANTENNA SYSTEM(S)

• US 20120281565A1
• Filed: 02/03/2012
• Published: 11/08/2012
• Est. Priority Date: 08/09/2010
• Status: Active Grant

• Current Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Original Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Inventors: Sauer, Michael
• Granted Patent: US 8,570,914 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 10/25752 Optical arrangements for wireless networks
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04W 16/20 for indoor coverage or short range network deployment
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings
• CPC Class Codes: H04W 4/40 for vehicles, e.g. vehicle-to-pedestrians [V2P]
• CPC Class Codes: H04W 4/60 Subscription-based services using application servers or record carriers, e.g. SIM application toolkits
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Distributed antenna systems provide location information regarding client devices communicating with remote antenna units (RAU) in a service area. The location information can be used to determine the location of client devices relative to the RAU(s) with which the client devices are communicating. A location processing unit (LPU) is configured to provide location information for client devices. The LPU includes a control system configured to receive uplink radio frequency (RF) signals communicated by a client device wirelessly communicating to a plurality of RAUs. The control system determines location information for a client device based on which RAU receives the strongest signal from the client device.

Claims

1. An apparatus for determining a location of a client device in a distributed antenna system in which multiple antennas are located in an indoor region, wherein each of the antennas is located in a known area and provides a respective coverage area for communicating with a client device, comprising:

a head-end unit configured to distribute downlink signals and combine uplink signals, wherein the downlink signals and the uplink signals are modulated according to the long term evolution (LTE) standard; and

a location processing unit (LPU) integrated in the head-end unit configured to be communicatively linked to a base station.

2. The apparatus of claim 1, wherein the LPU includes:

a plurality of signal monitoring devices configured to receive each of the uplink signals transmitted from the multiple antennas located in the known areas and acquire time slots of the downlink signals sent by the base station and split by the head-end unit; and

a location server configured to identify a transmitting client device by monitoring usage of a frequency band and deliver location information to the base station.

3. The apparatus of claim 1, wherein the head-end unit includes:

a unit of a combiner and a splitter configured to split the downlink signals sent by the base station and combine the uplink signals transmitted from the multiple antennas; and

a plurality of RF-to-FO converters configured to convert radio frequency (RF) signals to optical signals.

4. The apparatus of claim 1, wherein the base station has complete knowledge of time slot/frequency allocations of the client device in an uplink.

5. The apparatus of claim 1, wherein the antennas are antenna diversity using at least two receiving antennas per antenna location to receive RF signals sent by the client device.

6. The apparatus of claim 1, wherein the antennas are configured to use a multiple input/multiple output (MIMO) scheme.

7. A method for determining a location of a client device in a distributed antenna system in which multiple antennas are located in an indoor region, wherein each of the antennas is located in a known area and provides a respective coverage area for communicating with the client device, comprising:

selecting one or more specific time slot(s) from downlink radio frequency (RF) signals;

calculating received signal strength indication (RSSI) values for each of a plurality of resource blocks (RBs) at a specific time slot from uplink RF signals;

delivering the RSSI values of all the antennas to a location server of a location processing unit (LPU); and

identifying which of the antennas is closest to a transmitting client device by monitoring the RSSI values.

8. The method of claim 7, wherein the downlink RF signals are sent by a base station after being split by a splitter at a head-end unit.

9. The method of claim 7, wherein the uplink RF signals are received from the antennas located in the known areas before being combined together by a combiner at the head-end unit.

10. The method of claim 7, wherein the downlink RF signals and the uplink RF signals are converted to baseband by transceivers (TRXs).

11. The method of claim 10, wherein the downlink RF signals and the uplink RF signals are further digitized by a pair of analog-to-digital (ADC) converters.

12. The method of claim 7, further comprising at least two receiving antennas per antenna location to receive the downlink and uplink RF signals sent by the client device, wherein the RSSI values of at least two of the receiving antennas are calculated individually and then combined together.

13. The method of claim 8, where location information comprising maximum RSSI values with the respective antenna locations where those maximum RSSI values have been received are provided to the base station, which then combines the location information with a prior user allocation to provide a location estimate to a network.

14. The method of claim 12, further comprising control information retrieved from a control channel of the downlink RF signals in time division duplexing (TDD) mode, wherein the control information is assessed to additionally identify downlink and uplink transmission intervals.

15. The method of claim 12, wherein control information of downlink/uplink intervals is used to switch between downlink and uplink at a head-end unit.

16. The method of claim 12, further comprising a downlink/uplink switching signal provided by a base station, wherein the downlink/uplink switching signal is sent to the LPU to exclude downlink information.

17. A location processing unit (LPU) configured to provide location information for at least one client device wirelessly communicating in a distributed antenna system, comprising:

a control system configured to;

receive uplink radio frequency (RF) signals communicated by the at least one client device wirelessly communicating to a plurality of antenna units;

determine signal strengths of the uplink RF signals;

determine which antenna unit among the plurality of antenna units is receiving uplink RF signals from the at least one client device having the greatest signal strength; and

determine location information for the at least one client device based on identification of the antenna unit receiving the uplink RF signals from the at least one client device having the greatest signal strength.

18. The LPU of claim 17, wherein the received uplink RF signals are received in long term evolution (LTE) channels.

19. The LPU of claim 17, wherein the received uplink RF signals are received in channels separated into frequency blocks.

20. The LPU of claim 19, wherein the control system is configured to determine the signal strength of the uplink RF signals by measuring the signal strength of the frequency blocks in the uplink RF signals.

21. The LPU of claim 17, wherein the received uplink RF signals are received in channels separated into temporal blocks.

22. The LPU of claim 21, wherein the control system is configured to determine the signal strength of the uplink RF signals by measuring the signal strength of the temporal blocks in the uplink RF signals.

23. The LPU of claim 17, wherein the control system is configured to convert the received uplink RF signals into baseband uplink RF signals.

24. The LPU of claim 17, wherein the control system is further configured to synchronize to a downlink RF signal received from a base station.

25. The LPU of claim 17, wherein the control system is configured to determine the signal strengths of the uplink RF signals as a function of a fast Fourier transform (FFT) of a window of samples of the uplink RF signals.

26. The LPU of claim 17, wherein the control system is configured to receive the uplink RF signals communicated by at least one client device wirelessly communicating to a plurality of antenna units from a plurality of antennas provided at each of the plurality of antenna units.