Measuring interference in radio networks

• US 20060240782A1
• Filed: 04/26/2005
• Published: 10/26/2006
• Est. Priority Date: 04/26/2005
• Status: Active Grant

• Current Assignee: Ericsson Evdo, Inc. (CommScope Holding Company, Inc.)
• Original Assignee: Airvana Network Solutions Inc (Telefonaktiebolaget LM Ericsson)
• Inventors: Ananthaiyer, Satish, Pollman, Michael D., Grosch, Theodore O.
• Granted Patent: US 7,831,257 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336

Abstract

In a radio access network (e.g., a cellular network), a radio receiver is configured with a switch that alternatively couples an antenna and an impedance-matched load to the remainder of the receiver. Sector load, e.g., rise-over-thermal (ROT), is monitored by comparing a first measurement of signal power in a radio receiver (e.g., signal power output by the receiver) when the radio receiver is coupled to an antenna receiving the data traffic with a second measurement of signal power in the radio receiver when the radio receiver is de-coupled from the antenna.

Claims

1. A method comprising:

determining a first measurement of signal power in a radio receiver configured to receive data traffic in a sector of a radio access network when the radio receiver is receiving energy from an antenna that is receiving the data traffic and;

determining a second measurement of signal power in the radio receiver when the radio receiver is not receiving energy from the antenna; and

determining load in the sector based on the first and second measurements.

2. The method of claim 1 wherein the first measurement of signal power in a radio receiver comprises:

a first measurement of signal power output by the radio receiver.

3. The method of claim 1 wherein the first measurement of signal power in a radio receiver comprises:

a first measurement of signal power at the input of the radio receiver.

4. The method of claim 1 wherein determining a first measurement of signal power comprises:

obtaining an average signal power over a time period T1 when the radio receiver is receiving energy from the antenna.

5. The method of claim 4 wherein determining a second measurement of signal power comprises:

obtaining an average signal power over a time period T2 when the radio receiver is not receiving energy from the antenna.

6. The method of claim 1 wherein the load is determined based on comparing the first and second measurements.

7. The method of claim 6 in which the load is determined based on a ratio of the first measurement to the second measurement.

8. The method of claim 1 further comprising:

decoupling the antenna from the radio receiver using a switch.

9. The method of claim 8 further comprising:

using the switch to couple a resistive load having an impedance approximately equal to that of the antenna.

10. The method of claim 9 wherein determination of the second measurement occurs when the switch is coupled to the resistive load.

11. The method of claim 1 further comprising:

controlling transmission of data by access terminals in the sector based on the determined load in the sector.

12. The method of claim 11 wherein controlling transmission of data comprises controlling a rate at which data is transmitted by access terminals in the sector.

13. The method of claim 1 wherein the radio access network is a code division multiple access network.

14. The method of claim 1 wherein the radio access network is a first evolution data-only network.

15. The method of claim 1 further comprising:

causing access terminals within the sector to cease transmission for a time period.

16. The method of claim 15 wherein determining a second measurement of signal power occurs when the radio receiver is not receiving energy from the antenna and when the access terminals within the sector have ceased transmission.

17. The method of claim 16 further comprising:

determining a third measurement of signal power in the radio receiver when the radio receiver is receiving energy from the antenna and when the access terminals within the sector have ceased transmission.

18. The method of claim 17 further comprising:

determining a level of interference within the sector based on at least the second and third measurements.

19. The method of claim 17 further comprising:

determining a level of signal power from access terminals in the sector based on at least the first and third measurements.

20. The method of claim 8 wherein the receiver includes variable gain circuitry for dynamically adjusting a gain of the receiver, the method further comprising:

controlling the switch to keep a time period during which the antenna is de-coupled from the receiver at less than a response time of the variable gain circuitry.

21. The method of claim 1 wherein the receiver includes variable gain circuitry for dynamically adjusting a gain of the receiver, the method further comprising:

maintaining a gain of the variable gain circuitry approximately constant during a time when the second measurement is determined.

22. The method of claim 21 further comprising:

maintaining a gain of variable gain circuitry approximately constant during a time when the second measurement is determined.

23. The method of claim 21 wherein determination of the second measurement occurs over a time period that is less than a response time of a variable gain circuit in the receiver.

24. The method of claim 22 wherein determining a first measurement of signal power at the input of the radio receiver comprises:

deriving the first measurement from a measurement of signal power output at the receiver and a measurement of a gain of the receiver.

25. A method of monitoring load in a sector of a radio access network comprising a radio node having multiple receivers for receiving data traffic in a sector, the method comprising:

de-coupling the first receiver from an antenna configured to receive data traffic;

maintaining at least one other receiver coupled to an antenna while the first receiver is de-coupled from its antenna; and

determining a measurement of signal power in the first receiver when the first receiver is de-coupled from its antenna.

26. The method of claim 25 wherein maintaining at least one other receiver coupled to the antenna comprises:

ensuring that only one receiver is de-coupled from its antenna at any one time.

27. The method of claim 25 further comprising:

determining a measurement of signal power in a receiver when the receiver is coupled to an antenna.

28. The method of claim 27 wherein the first receiver is the receiver for which a measurement of signal power is determined when the receiver is coupled to the antenna.

29. The method of claim 27 further comprising:

determining load in the sector based on the measurement of signal power when the first receiver is de-coupled from the antenna and the measurement of signal power when a receiver is coupled to an antenna.

30. The method of claim 25 wherein controlling a switch to de-couple the first receiver comprises coupling the first receiver to a load having an impedance approximately equal to that of the antenna.

31. The method of claim 25 wherein determining a measurement of signal power comprises:

obtaining an average signal power over a time period when the radio receiver is de-coupled from the antenna.

32. The method of claim 25 wherein determining a measurement of signal power in the receiver comprises determining a measurement of signal power output by the receiver.

33. The method of claim 25 wherein determining a measurement of signal power in the receiver comprises determining a measurement of signal power input to the receiver.

34. The method of claim 32 wherein the first receiver includes variable gain circuitry for dynamically adjusting a gain of the first receiver, the method further comprising:

controlling the switch to keep a time period during which the antenna is de-coupled from the first receiver at less than a response time of the variable gain circuitry.

35. The method of claim 32 wherein the first receiver includes variable gain circuitry for dynamically adjusting a gain of the first receiver, the method further comprising:

maintaining a gain of the variable gain circuitry approximately constant during a time when the measurement is determined.

36. Apparatus comprising:

a radio receiver for receiving data traffic from sources in a sector of a cellular network, the radio receiver including an antenna configured to receive data traffic;

a switch for selectively coupling and de-coupling the antenna from the remainder of the radio receiver; and

a rise-over-thermal measurement module configured to control the switch to determine a rise-over-thermal value for the receiver based on a ratio of signal power in the receiver when the switch is coupled to the antenna to signal power in the receiver when the switch is de-coupled from the antenna.

37. The apparatus of claim 36 wherein the radio receiver further comprises variable gain circuitry for dynamically adjusting a gain of the signal output by the receiver, and wherein the rise-over-thermal measurement module is configured to control the switch such that the a time period during which the antenna is de-coupled from the first receiver is less than a response time of the variable gain circuitry.

38. The apparatus of claim 36 wherein the radio receiver further comprises variable gain circuitry for dynamically adjusting a gain of a signal output by the receiver, and wherein the rise-over-thermal measurement module is configured to maintain a gain of the variable gain circuitry approximately constant during a time when the measurement is determined.

39. The apparatus of claim 36 further comprising:

one or more additional radio receivers, each for receiving data traffic from sources in the sector of a cellular network and each including an antenna configured to receive data traffic;

a switch for selectively coupling and de-coupling each diversity receiver to its respective antenna; and

wherein the rise-over-thermal measurement module is configured to maintain at least one receiver coupled to its antenna while any other receiver is de-coupled from its antenna.

40. The apparatus of claim 36 further comprising a resistive load having an impedance approximately equal to that of the receiver.

41. The apparatus of claim 40 wherein the switch is configured to alternatively couple the antenna and resistive load to the remainder of the receiver.

42. Apparatus comprising

a device to determine a rise-over thermal value for a receiver that receives data traffic from sources in a section of a cellular network based on a relationship of signal power in the receiver when the receiver is receiving energy from an antenna and signal power in the receiver when the receiver is not receiving energy from the antenna.