Methods and apparatus for detecting and mitigating radio interference among user equipment and base stations of geographically co-located and spectrally distinct wireless systems

• US 8,655,304 B2
• Filed: 12/29/2011
• Issued: 02/18/2014
• Est. Priority Date: 12/29/2011
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Makhlouf, Isam R., Chen, Ethan Y., Jin, Xiaowei
• Primary Examiner(s): Kincaid, Lester
• Assistant Examiner(s): Lai, Daniel
• Application Number:
  US13/340,135
• Publication Number:
  US 20130171955A1
• Time in Patent Office: 782 Days
• Field of Search: 455/426.1, 455 631- 65, 455/114.2, 455/114.3, 455/278.1, 455/279.1, 455/296, 455/297
• US Class Current: 455/404.1
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]

Abstract

Methods and apparatus are provided for detecting interference between spectrally distinct wireless communication networks. A first base station in a first network communicates with a first mobile device at a first frequency, and a second base station communicates at a second frequency with a second mobile device geographically co-located with the first mobile device. The power level of an interfering signal received at the first base station from the second mobile device may be estimated by sharing information between the two networks through an interoperability gateway. The path loss of a reference signal transmitted from the first mobile device to its base station is communicated to the gateway, along with a parameter associated with the transmit power level of the interfering signal. Based on this parameter and the reference signal path loss, the received power level of the interfering signal may be inferred.

Claims

1. A method of estimating the power level of an interfering radio signal that is received at a first base station configured to communicate with a first mobile device at a first frequency, and which is transmitted by a second mobile device configured to communicate with a second base station at a second frequency, wherein the first and second mobile devices are geographically co-located and said first and second base stations share an interoperability gateway, the method comprising:

calculating a path loss of a reference signal transmitted between said first mobile device and said first base station;

providing a first parameter associated with a transmit power of said interfering signal to said interoperability gateway;

estimating, based on said path loss and said first parameter, the received power level of said interfering radio signal; and

causing said interfering signal to be mitigated based on said estimating step.

2. The method according to claim 1, wherein:

said first base station is a public safety land mobile radio base station, and said first mobile device is a public safety land mobile radio device; and

said second base station is a Public Safety broadband base station, and said second mobile device is a broadband radio device.

3. The method according to claim 2, wherein:

said first mobile device transmits on a narrow band channel in the range of 799 to 815 megahertz; and

said second mobile device transmits on a broadband channel in the range of 788 to 798 megahertz.

4. The method according to claim 1, wherein causing said interfering signal to be mitigated comprises reducing the transmit power of said interfering signal.

5. The method according to claim 1, wherein causing said interfering signal to be mitigated comprises rescheduling the transmission of said interfering signal.

6. The method according to claim 1, further comprising providing the interoperability gateway as a computer based platform for sharing operational data between base stations operating in spectrally distinct wireless networks and for estimating said received power level of said interfering radio signal.

7. The method according to claim 1, wherein calculating the path loss comprises:

determining a power level at which said reference signal is transmitted by said first mobile device;

determining a power level at which said reference signal is received at said first base station; and

determining a difference between the power level at which said reference signal is transmitted and the power level at which said reference signal is received.

8. The method according to claim 1, wherein providing a first parameter comprises:

determining a power level at which said interfering signal is transmitted by said second mobile device;

assigning said power level of said interfering signal to said first parameter;

providing said first parameter to said gateway by said second base station; and

providing said first parameter to said first base station by said gateway.

9. The method according to claim 8, wherein estimating the received power level comprises subtracting a path loss of said interfering signal, inferred from the path loss of the reference signal, from said transmit power of said interfering signal.

10. The method according to claim 1, wherein said first mobile device is a hand-held unit, and said second mobile device is an LTE compliant vehicular modem.

11. The method according to claim 1, wherein said first and second mobile devices are geographically co-located (i) in a same vehicle, (ii) in a same room, or (iii) on a same person.

12. The method of claim 11, wherein said first and second mobile devices are geographically co-located in the same vehicle.

13. A method for detecting a predetermined threshold level of radio frequency interference from an adjacent frequency channel, the method comprising:

determining a transmit power level at which a reference signal is transmitted from a first mobile device to a first base station in a first frequency band and in accordance with a first modulation scheme;

determining a received power level at which said reference signal is received at said first base station;

determining a path loss of said reference signal by subtracting said received power of said reference signal from said transmit power of said reference signal;

determining a transmit power level at which a second signal is transmitted from a second mobile device to a second base station in a second frequency band and in accordance with a second modulation scheme;

interrogating a database and determining that said first and said second mobile devices are geographically co-located;

estimating a received power level at which said second signal is received at said first base station by subtracting said path loss from said transmit power level of said second signal; and

comparing said received power of said second signal to a threshold value.

14. The method according to claim 13, wherein:

said first frequency band is in a range of 799 to 815 megahertz;

said second frequency band is in a range of 788 to 798 megahertz;

said first modulation scheme is compliant with Public Safety narrow band voice modulation standards; and

said second modulation scheme is a Long Term Evolution (LTE) compliant broadband scheme.

15. The method according to claim 13, wherein said database comprises information pertaining to a plurality of emergency response Public Safety vehicles and mobile devices which are co-located in a same vehicle.

16. The method according to claim 13, further comprising executing a mitigation protocol when said received power of said second signal exceeds said threshold value.

17. The method according to claim 16, wherein said mitigation protocol comprises at least one of:

terminating said second signal;

reducing a transmit power of said second signal;

changing a modulation scheme of said second signal; and

changing a frequency at which said second signal is transmitted.

18. The method of claim 13, further comprising interrogating the database and determining that said first and second mobile devices are geographically co-located comprises determining that said first and second mobile devices are geographically co-located (i) in a same vehicle, (ii) in a same room, or (iii) on a same person.

19. A system for determining a power level at which a signal transmitted between a first radio and a first base station in a first network is received at a second network operating in an adjacent RF channel and including a second base station and a second radio geographically co-located with said first radio, the system comprising:

a gateway for sharing operational data between said networks; and

a computer configured to communicate with said gateway and to;

calculate a first path loss associated with a first signal transmitted between said first radio and said first base station;

estimate, based on said first path loss, a second path loss associated with a second signal transmitted between said first network and said second network;

determine a power level at which said second signal is received, based on the difference between;

a) a power level at which said second signal is transmitted; and

b) said second path loss;

compare said received power of said second signal to a threshold value; and

direct, via said gateway, said second base station to execute an interference mitigation protocol if said power level of said second signal exceeds said threshold value.

20. The system of claim 19, wherein the first radio and the second radio are geographically co-located (i) in a same vehicle, (ii) in a same room, or (iii) on a same person.