Method and apparatus for adaptive rate selection in a communication system

• US 6,760,313 B1
• Filed: 06/19/2000
• Issued: 07/06/2004
• Est. Priority Date: 06/19/2000
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wu, Qiang, Sindhushayana, Nagabhushana T., Esteves, Eduardo A. S., Attar, Rashid A.
• Primary Examiner(s): HO, DUC CHI
• Application Number:
  US09/597,516
• Time in Patent Office: 1,478 Days
• Field of Search: 370/252, 370/230, 370/232, 370/235, 370/333, 370/328, 370/338, 370/465, 375/225, 375/227, 455/63, 714/704
• US Class Current: 370/252
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate

Abstract

A method and an apparatus for adaptive data rate selection in a high data rate (HDR) communication system are disclosed. An exemplary HDR communication system defines a set of data rates, at which an access point (AP) may transmit data packets to an access terminal (AT). The transmission data rate is selected to maintain target packet error rate (PER). Each AT monitors signal quality metric of signals received from APs. An AT receiving forward link signals from multiple ATs identifies the AT associated with the highest quality forward link signal. The AT then evaluates the rate at which a tail probability of error is greater than or equal to a target tail probability of error. The AT then generates a prediction of a first data rate at which the PER of packets received from the identified AP will not exceed the target PER, and a prediction of a second data rate at which the PER of packets received from the selected AP will exceed the target PER. The AT uses the values of the first and second data rates to predict probabilities of selecting the first and the second data rates such that a throughput of the HDR system is maximized and the target PER is achieved. The predicted probabilities are then utilized as biases for a method identifying whether the first data rate or the second data rate will be requested from the AP. The disclosed method and apparatus may be extended to the full set of available data rates.

Claims

1. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first data rate a packet error rate of which is smaller than said target packet error rate, comprising;

selecting a target tail probability of error;

determining a first quality metric corresponding to said target tail probability; and

selecting said first data rate a quality metric of which is smaller than said first quality metric;

predicting a second data rate a packet error rate of which is greater than said target packet error rate;

predicting a third data rate a packet error rate of which is greater than said target packet error rate; and

requesting said first data rate or said second data rate or said third data rate to achieve said target packet error rate.

2. The method of claim 1 wherein said quality metric of said first data rate is further adjacent to said first quality metric.

3. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first data rate a packet error rate of which is smaller than said target packet error rate;

predicting a second data rate a packet error rate of which is greater than said target packet error rate, comprising;

selecting a target tail probability of error;

determining a first quality metric corresponding to said target tail probability; and

selecting said second data rate a quality metric of which is greater than said first quality metric;

predicting a third data rate a packet error rate of which is greater than said target packet error rate; and

requesting said first data rate or said second data rate or said third data rate to achieve said target packet error rate.

4. The method of claim 3 wherein said quality metric of said second data rate is further adjacent to said first quality metric.

5. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first data rate a packet error rate of which is smaller than said target packet error rate;

predicting a second data rate a packet error rate of which is greater than said target packet error rate;

predicting a third data rate a packet error rate of which is greater than said target packet error rate, comprising;

selecting a target tail probability of error;

determining a first quality metric corresponding to said target tail probability; and

selecting said third data rate a quality metric of which is greater than said first quality metric, and said third data rate is greater than said second data rate; and

requesting said first data rate or said second data rate or said third data rate to achieve said target packet error rate.

6. The method of claim 5 wherein said third data rate is further adjacent to said second quality metric.

7. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first data rate a packet error rate of which is smaller than said target packet error rate;

predicting a second data rate a packet error rate of which is greater than said target packet error rate;

predicting a third data rate a packet error rate of which is greater than said target packet error rate; and

requesting said first data rate or said second data rate or said third data rate to achieve said target packet error rate, comprising;

determining a first packet error rate probability for a first data rate;

determining a second packet error rate probability for a second data rate;

determining a third packet error rate probability for a third data rate; and

determining said first data rate or said second data rate or said third data rate in accordance with said first packet error rate probability, said second packet error rate probability, and said third packet error rate probability.

8. The method of claim 7 further comprising:

modifying said first packet error rate probability in accordance with a current predicted signal quality metric;

modifying said second packet error rate probability in accordance with said current predicted signal quality metric; and

modifying said third packet error rate probability in accordance with a current predicted signal quality metric.

9. The method of claim 7 wherein said determining of a first packet error rate probability, a second packet error rate probability, and a third packet error rate probability is carried out in accordance with a true packet event.

10. The method of claim 7 wherein said determining of a first packet error rate probability, a second packet error rate probability, and a third packet error rate probability is carried out in accordance with a fast-track method.

11. The method of claim 7 wherein said determining of said first data rate or said second data rate or said third data rate comprises:

calculating a first probability of selecting said first data rate and a second probability of selecting said second data rate so that a first throughput of said communication system is maximized and said target packet error rate is achieved;

calculating a third probability of selecting said first data rate and a fourth probability of selecting said third data rate so that a second throughput of said communication system is maximized and said target packet error rate is achieved;

selecting said first data rate or said second data rate in accordance with said first probability and said second probability when said first throughput is greater than said second throughput; and

selecting said first data rate or said third data rate in accordance with said third probability and said fourth probability when said first throughput is smaller than said second throughput.

12. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first data rate a packet error rate of which is greater than said target packet error rate;

select a second data rate a packet error rate of which is greater than said target packet error rate; and

select a third data rate a packet error rate of which is greater than said target packet error rate;

request said first data rate or said second data rate said third data rate to achieve said target packet error rate,

wherein said processor predicts a first data rate by being configured to;

select a target tail probability of error;

determine a first quality metric corresponding to said target tail probability; and

select said first data rate a quality metric of which is smaller than said first quality metric.

13. The apparatus of claim 12 wherein said quality metric of said first data rate is further adjacent to said first quality metric.

14. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first data rate a packet error rate of which is greater than said target packet error rate;

select a second data rate a packet error rate of which is greater than said target packet error rate; and

select a third data rate a packet error rate of which is greater than said target packet error rate;

request said first data rate or said second data rate said third data rate to achieve said target packet error rate,

wherein said processor predicts a second data rate by being configured to;

select a target tail probability of error;

determine a first quality metric corresponding to said target tail probability; and

select said second data rate a quality metric of which is greater than said first quality metric.

15. The apparatus of claim 14 wherein said quality metric of said second data rate is further adjacent to said first quality metric.

16. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first data rate a packet error rate of which is greater than said target packet error rate;

select a second data rate a packet error rate of which is greater than said target packet error rate; and

select a third data rate a packet error rate of which is greater than said target packet error rate;

request said first data rate or said second data rate said third data rate to achieve said target packet error rate,

wherein said processor predicts a third data rate by being configured to;

select a target tail probability of error;

determine a first quality metric corresponding to said target tail probability; and

select said third data rate a quality metric of which is greater than said first quality metric and said third data rate is greater than said second data rate.

17. The apparatus of claim 16, wherein said quality metric of said third data rate is further adjacent to said second data rate.

18. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first data rate a packet error rate of which is greater than said target packet error rate;

select a second data rate a packet error rate of which is greater than said target packet error rate; and

select a third data rate a packet error rate of which is greater than said target packet error rate;

request said first data rate or said second data rate said third data rate to achieve said target packet error rate,

wherein said processor requests said first data rate or said second data rate or said third data rate by being configured to;

determine a first packet error rate probability for a first data rate;

determine a second packet error rate probability for a second data rate;

determine a third packet error rate probability for a third data rate; and

determine said first data rate or said second data rate or said third data rate in accordance with said first packet error rate, said second packet error rate probability, and said third packet error rate probability.

19. The apparatus of claim 18 wherein said processor is further configured to:

modify said first packet error rate probability in accordance with a current predicted signal quality metric;

modify said second packet error rate probability in accordance with said current predicted signal quality metric; and

modify said third packet error rate probability in accordance with said current predicted signal quality metric.

20. The apparatus of claim 18 wherein said processor is configured to determine said first packet error rate probability, said second packet error rate probability, and said third packet error rate probability in accordance with a true packet event.

21. The apparatus of claim 18 wherein said processor is configured to determine said first packet error rate probability, said second packet error rate probability, and said third packet error rate probability in accordance with a fast-track method.

22. The apparatus of claim 18 wherein said processor determines said first data rate or said second data rate or said third data rate by being configured to:

calculate a first probability of selecting said first data rate and a second probability of selecting said second data rate so that a throughput of said communication system is maximized and said target packet error rate is achieved; and

calculate a third probability of selecting said first data rate and a fourth probability of selecting said third data rate so that a second throughput of said communication system is maximized and said target packet error rate is achieved;

select said first data rate or said second data rate in accordance with said first probability and said second probability when said first throughput is greater than said second throughput; and

select said first data rate or said third data rate in accordance with said third probability and said fourth probability when said first throughput is smaller than said second throughput.

23. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first set of data rates a packet error rate of which is smaller than said target packet error rate, comprising;

selecting a target tail probability of error;

determining a first quality metric corresponding to said target tail probability; and

selecting said first set of data rates a quality metric of which is smaller than said first quality metric;

predicting a second set of data rates a packet error rate of which is greater than said target packet error rate; and

requesting a first data rate from said first set or a second data rate from said second set to achieve said target packet error rate.

24. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first set of data rates a packet error rate of which is smaller than said target packet error rate;

predicting a second set of data rates a packet error rate of which is greater than said target packet error rate, comprising;

selecting a target tail probability of error;

determining a first quality metric corresponding to said target tail probability; and

selecting said second set of data rates a quality metric of which is greater than said first quality metric; and

requesting a first data rate from said first set or a second data rate from said second set to achieve said target packet error rate.

25. A method for an adaptive data rate selection in a communication system, comprising:

selecting a target packet error rate;

predicting a first set of data rates a packet error rate of which is smaller than said target packet error rate;

predicting a second set of data rates a packet error rate of which is greater than said target packet error rate; and

requesting a first data rate from said first set or a second data rate from said second set to achieve said target packet error rate, comprising;

determining a packet error rate probability for each data rate; and

determining said first data rate from said first set or said second data rate from said second set in accordance with said packet error rate probabilities.

26. The method of claim 25 further comprising modifying said packet error rate probabilities in accordance with a current predicted signal quality metric.

27. The method of claim 25 wherein said determining of said packet error rate probabilities is carried out in accordance with a true packet event.

28. The method of claim 25 wherein said determining of said packet error rate probabilities is carried out in accordance with a fast-track method.

29. The method of claim 25 wherein said determining of said first data rate or said second data rate comprises:

calculating a probability of selecting each of said data rates so that a throughput of said communication system is maximized and said target packet error rate is achieved; and

selecting said first data rate or said second data rate in accordance with said probabilities.

30. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first set of data rates a packet error rate of which is smaller than said target packet error rate;

select a second set of data rates a packet error rate of which is greater than said target packet error rate; and

request a first data rate from said first set or a second data rate from said second set to achieve said target packet error rate,

wherein said processor selects a first set of data rates by being configured to;

select a target tail probability of error;

determine a first quality metric corresponding to said target tail probability; and

select said first set of data rates a quality metric of which is smaller than said first quality metric.

31. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first set of data rates a packet error rate of which is smaller than said target packet error rate;

select a second set of data rates a packet error rate of which is greater than said target packet error rate; and

request a first data rate from said first set or a second data rate from said second set to achieve said target packet error rate,

wherein said processor selects a second set of data rates by being configured to;

select a target tail probability of error;

determine a first quality metric corresponding to said target tail probability; and

select said second set of data rates a quality metric of which is greater than said first quality metric.

32. An apparatus for an adaptive data rate selection in a communication system, comprising:

a memory for storing a target packet error rate; and

a processor coupled to said memory configured to;

select a first set of data rates a packet error rate of which is smaller than said target packet error rate;

select a second set of data rates a packet error rate of which is greater than said target packet error rate; and

request a first data rate from said first set or a second data rate from said second set to achieve said target packet error rate,

wherein said processor requests said first data rate or said second data rate by being configured to;

determine a packet error rate probability for each data rate; and

determine said first data rate from said first set or said second data rate from said second set in accordance with said packet error rate probability for each data rate.

33. The apparatus of claim 32 wherein said processor is further configured to modify said packet error rate probability for each data rate in accordance with a current predicted signal quality metric.

34. The apparatus of claim 32 wherein said processor is configured to determine said packet error rate probability for each data rate in accordance with a true packet event.

35. The apparatus of claim 32 wherein said processor is configured to determine said first packet error rate probability for each data rate in accordance with a fast-track method.

36. The apparatus of claim 32 wherein said processor determines said first data rate or said second data rate by being configured to:

calculate a probability of selecting each of said data rates so that a throughput of said communication system is maximized and said target packet error rate is achieved; and

selecting sa id first data rate or said second data rate in accordance with said probabilities.