ESTIMATING LINK QUALITIES IN MULTI-CARRIER SYSTEMS

• US 20100087152A1
• Filed: 10/06/2009
• Published: 04/08/2010
• Est. Priority Date: 10/08/2008
• Status: Active Grant

• Current Assignee: Ueran Technology LLC
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: MOURAD, Alain Abdel-Majid
• Granted Patent: US 8,498,580 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04B 17/0085 using test signal generators
• CPC Class Codes: H04B 17/373 Predicting channel quality or other radio frequency [RF] parameters
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling

Abstract

A method for estimating qualities of links between a transmitter and a receiver on respective carrier frequencies in a multi-carrier wireless communication system from measurements made during a scanning interval in which pilot signals may be transmitted from the transmitter to the receiver in a plurality of carrier-time bins, each carrier-time bin corresponding to a respective carrier frequency of the multi-carrier system and a respective time slot within the scanning interval, are provided. The method includes, during the scanning interval, making test measurements in less than all of the carrier-time bins, each test measurement comprising transmitting a respective signal from the transmitter to the receiver in a respective carrier-time bin and measuring a strength of the corresponding signal received by the receiver, and using the test measurements to determine at least one of: a value indicative of a predicted quality of a link between the transmitter and the receiver in a carrier-time bin of the scanning interval in which no test measurement is made during the scanning interval, and a value indicative of a predicted quality of a link between the transmitter and the receiver over a period of time within or equal to the scanning interval on a carrier frequency for which no test measurement is made in at least one carrier-time bin during said period of time.

Claims

1. A method for estimating qualities of links between a transmitter and a receiver on respective carrier frequencies in a multi-carrier wireless communication system from measurements made during a scanning interval in which pilot signals may be transmitted from the transmitter to the receiver in a plurality of carrier-time bins, each carrier-time bin corresponding to a respective carrier frequency of the multi-carrier system and a respective time slot within the scanning interval, the method comprising:

during the scanning interval, making test measurements in less than all of the carrier-time bins, each test measurement comprising transmitting a respective signal from the transmitter to the receiver in a respective carrier time bin and measuring a strength of the corresponding signal received by the receiver; and

using the test measurements to determine at least one of;

a value indicative of a predicted quality of a link between the transmitter and the receiver in a carrier-time bin of the scanning interval in which no test measurement is made during the scanning interval; and

a value indicative of a predicted quality of a link between the transmitter and the receiver over a period of time within or equal to the scanning interval on a carrier frequency for which no test measurement is made in at least one carrier-time bin during said period of time.

2. The method of claim 1, further comprising:

prior to the scanning interval, making a plurality of preliminary measurements, said preliminary measurements being indicative of a least one of;

a variation with time in a quality of a link between the transmitter and the receiver on at least one of said carrier frequencies in the multi-carrier wireless communication system; and

a correlation between the quality of a link between the transmitter and the receiver on one of said carrier frequencies in the multi-carrier system and a quality of a link between the transmitter and the receiver on at least one different one of said carrier frequencies in the multi-carrier system.

3. The method of claim 1, wherein said making of said test measurements comprises:

making a first plurality of said test measurements in a first period of the scanning interval, the first plurality of test measurements comprising a respective test measurement on each of the plurality of carrier frequencies.

4. The method of claim 3, wherein each of the first plurality of test measurements is made in a different respective time slot.

5. The method of claim 3, wherein said using of the test measurements comprises determining a respective value indicative of a predicted quality of a link between the transmitter and the receiver in each carrier-time bin of the first period of scanning interval in which no test measurement is made from all of the first plurality of measurements.

6. The method of claim 3, wherein said using of the test measurements comprises determining a respective value indicative of a predicted quality of a link between the transmitter and the receiver in each carrier-time bin of the first period of the scanning interval in which no test measurement is made by multiplying a result of a respective one of the first plurality of test measurements by a respective multiplication factor.

7. The method of claim 6, wherein the respective multiplication factor is determined from preliminary measurements.

8. The method of claim 3, wherein said making of said test measurements comprises:

making a second plurality of said test measurements in a second period of the scanning interval, the second plurality of test measurements comprising a respective test measurement on each of the plurality of carrier frequencies.

9. The method of claim 8, wherein each of the second plurality of test measurements is made in a different respective time slot.

10. The method of claim 8, wherein said using of the test measurements comprises determining a respective value indicative of a predicted quality of a link between the transmitter and the receiver in each carrier-time bin of the second period of the scanning interval in which no test measurement is made from all of the second plurality of measurements.

11. The method of claim 8, wherein the second period of the scanning interval is immediately after the first period of the scanning interval.

12. The method of claim 8, wherein the second period of the scanning interval begins a time interval after the end of the first period of the scanning interval.

13. The method of claim 12, further comprising determining the delay time interval.

14. The method of claim 12, wherein said making of said test measurements comprises:

making a third plurality of said test measurements in a third period of the scanning interval, the third period being between the first and second periods.

15. The method of claim 14, wherein each of the third plurality of test measurements is made in a different respective time slot on the same carrier frequency.

16. The method of claim 14, wherein said using of the test measurements comprises determining a respective value indicative of a predicted quality of a link between the transmitter and the receiver in each carrier-time bin of the third period of scanning interval in which no test measurement is made from a measurement made in another carrier-time bin of the third time period and at least one test measurement made during the first time period.

17. The method of claim 12, comprising making no test measurements between the first and second periods.

18. The method of claim 8, wherein said making of said test measurements comprises:

making a fourth plurality of said test measurements in a fourth period of the scanning interval, the fourth period being after the second period.

19. The method of claim 18, wherein each of the fourth plurality of test measurements is made in a different respective time slot on the same carrier frequency.

20. The method of claim 1, wherein the receiver comprises a mobile receiver traveling at a speed v(t), the method further comprising:

measuring a first speed v₀ of the mobile receiver at a first time t_o;

performing a plurality of measurements of received signal strength at the mobile receiver versus time on at least one carrier frequency in a first time period following said first time;

determining from the first plurality of measurements a first value of a parameter indicative of a rate of variation of a received signal strength with time at the mobile receiver resulting from time-dependent fading between the transmitter and the receiver;

measuring a second speed v_n, of the mobile receiver at a second, later time t_n; and

determining a second value of said parameter, indicative of a second rate of said variation corresponding to speed v_n, from the said first value and the first and second speeds.

21. The method of claim 20, further comprising using said second value to determine at least one of said values indicative of a predicted quality of a link.

22. The method of claim 20, wherein said performing of said plurality of measurements is performed before the scanning interval.

23. The method of claim 20, further comprising determining a measurement time interval according to the first speed, wherein said performing a plurality of measurements comprises performing a respective measurement of received signal strength at each of a series of times, adjacent said times being separated by the measurement time interval.

24. The method of claim 20, wherein said second time falls within the scanning interval.

25. The method of claim 20, wherein said parameter indicative of a rate of variation of a received signal strength with time is an exponential time decay rate parameter u.

26. The method of claim 25, wherein said first value is u_o, said second value is u_n and u_n=u₀(v_n/v₀).

27. A method of determining a value of a parameter indicative of a rate of variation of a received signal strength with time at a mobile receiver, traveling at a speed v(t), as a result of time-dependent fading between a transmitter and the mobile receiver, the method comprising:

measuring a first speed v₀ of the mobile receiver at a first time t_o;

performing a plurality of measurements of received signal strength at the mobile receiver versus time in a first time period following said first time;

determining from the first plurality of measurements a first value of a parameter indicative of a first rate of said variation of received signal strength with time;

measuring a speed v_n of the mobile receiver at a later time t_n; and

determining a second value of said parameter, indicative of a second rate of said variation corresponding to speed v_n, from the first said value and the first and second speeds.

28. The method of claim 27, further comprising determining a measurement time interval according to the first speed, wherein said performing of said plurality of measurements comprises performing a respective measurement of received signal strength at each of a series of times, adjacent said times being separated by the measurement time interval.

29. The method of claim 28, wherein said parameter indicative of a rate of variation of a received signal strength with time comprises an exponential time decay rate parameter u.

30. The method of claim 29, wherein said first value is u_o, said second value is u_n, and u_n=u₀·

(v_n/v₀).

31. A computer readable medium having stored thereon instructions arranged, when executed, to implement a method for estimating qualities of links between transmitter and receiver on respective carrier frequencies in a multi-carrier wireless communication system from measurements made during a scanning interval in which pilot signals may be transmitted from the transmitter to the receiver in a plurality of carrier-time bins, each carrier-time bin corresponding to a respective carrier frequency of the multi-carrier system and a respective time slot within the scanning interval, the method comprising:

during the scanning interval, making test measurements in less than all of the carrier-time bins, each test measurement comprising transmitting a respective signal from the transmitter to the receiver in a respective carrier time bin and measuring a strength of the corresponding signal received by the receiver; and

using the test measurements to determine at least one of;

a value indicative of a predicted quality of a link between the transmitter and the receiver in a carrier-time bin of the scanning interval in which no test measurement is made during the scanning interval; and

a value indicative of a predicted quality of a link between the transmitter and the receiver over a period of time within or equal to the scanning interval on a carrier frequency for which no test measurement is made in at least one carrier-time bin during said period of time.