Method and apparatus for optimizing target error rates for link adaptation in a communication system

1. A method comprising:

estimating a data rate associated with transmission of a data stream over a communication link according to a pre-defined communication protocol;

selecting a required target error rate from a plurality of pre-defined target error rate values based on whether the estimated data rate is within a range of at least one of a plurality of pre-defined data rate threshold values, wherein each of the pre-defined target error rate values is mapped to one of the plurality of pre-defined data rate threshold values, and wherein the pre-defined data rate threshold values are selected, and the plurality of pre-defined target error rate values are mapped to the pre-defined data rate threshold values, such that the selected target error rate is higher than a target error rate which the communication protocol specifies for the estimated data rate;

updating a link adaptation parameter associated with the communication link to maintain the required target error rate; and

transmitting the data stream over the communication link using the updated link adaptation parameter.

2. The method as claimed in claim 1 , wherein updating a link adaptation parameter comprises

changing from a first link adaptation parameter to a second link adaptation parameter, and

transmitting the data stream on the communication link using the second link adaptation parameter.

3. The method as claimed in claim 2 , wherein

when the estimated data rate is above a first pre-defined data rate threshold value of the plurality of pre-defined data rate threshold values, the transmission of data stream using the second link adaptation parameter has lower error tolerance than the transmission of data stream using the first link adaptation parameter, and

when the estimated data rate is below the first pre-defined data rate threshold value of the plurality of pre-defined data rate threshold values, the transmission of data stream using the second link adaptation parameter has higher error tolerance than the transmission of data stream using the first link adaptation parameter.

4. The method as claimed in claim 1 , wherein estimating data rate further comprises

monitoring data rate associated with transmission of a previous data stream on the communication link during a pre-determined period of time, and

estimating the data rate based on at least one of a peak data rate, a maximum data rate, and a sustained data rate achieved during the transmission of the previous data stream over the pre-determined period of time.

5. The method as claimed in claim 1 , wherein estimating data rate further comprises

monitoring data rate associated with transmission of a previous data stream on the communication link over a pre-determined period of time, and

estimating the data rate based on whether a sustained data rate is above a pre-defined data rate.

6. The method as claimed in claim 1 , wherein estimating data rate further comprises

monitoring data rate associated with transmission of a previous data stream on the communication link over a pre-determined period of time, and

estimating the data rate based on a percentile of sustained data rate that is above a pre-defined data rate over the pre-determined period of time.

7. The method as claimed in claim 1 , wherein estimating the data rate is based on a pre-negotiated service rate including at least one of a guaranteed bit rate, a maximum sustained data rate, and a minimum sustained data rate associated with transmission of the data stream.

8. The method as claimed in claim 1 , wherein updating a link adaptation parameter comprises updating at least one of a modulation and coding scheme, a transmission power, and an error protection scheme.

9. The method as claimed in claim 2 , wherein the first link adaptation parameter includes a modulation and coding scheme of quadrature phase shift keying with a code rate of ¾, while the second link adaptation parameter includes a 16 quadrature amplitude modulation with a code rate of ½.

10. The method as claimed in claim 1 , wherein the target error rate is at least one of a packet error rate, a frame error rate, and a block error rate.

11. A method, comprising

estimating a data rate associated with transmission of a data stream on a communication link according to a pre-defined communication protocol;

comparing the estimated data rate with a pre-defined data rate threshold value;

when the estimated data rate is above the pre-defined data rate threshold value,

selecting a first target error rate based on the estimated data rate, and

selecting a link adaptation parameter for transmitting the data stream on the communication link, such that, the selected link adaptation parameter provides the selected first target error rate; and

when the estimated data rate is below the pre-defined data rate threshold value,

selecting a second target error rate based on the estimated data rate, and

selecting a link adaptation parameter for transmitting the data stream on the communication link, such that, the selected link adaptation parameter provides the selected second target error rate,

wherein the transmission of the data stream using the link adaptation parameter providing the selected first target error rate has lower error tolerance than the transmission of the data stream using the link adaptation parameter providing the second target error rate, and

wherein the pre-defined data rate threshold value is selected, and the first target error rate and the second target error rate are mapped to the pre-defined data rate threshold value, such that the second target error rate is higher than a target error rate which the communication protocol specifies for the estimated data rate.

12. The method as claimed in claim 11 , further comprising

selecting the first target error rate of 10 −4 , when the estimated data rate is above the pre-defined data rate threshold value of 30 megabits per second (Mbps), and

selecting the link adaptation parameter for transmitting the data stream on the communication link to select at least one of a first modulation and coding scheme, a first transmission power, and a first error protection scheme.

13. The method as claimed in claim 12 , further comprising

selecting the second target error rate of at least one of 10 −3 and 10 −2 , when the estimated data rate is below the pre-defined data rate threshold value of 30 Mbps, and

selecting the link adaptation parameter for transmitting the data stream on the communication link to select at least one of a second modulation and coding scheme, a second transmission power, and a second error protection scheme,

wherein the first modulation and coding scheme is at a lower level than the second modulation and coding scheme, the first transmission power is higher than the second transmission power, and the first error protection scheme is less tolerant to error than the second error protection scheme.

14. The method as claimed in claim 11 , further comprising

monitoring data rate associated with transmission of a previous data stream on the communication link over a pre-determined period of time, and

estimating the data rate based on at least one of a peak data rate, or a maximum data rate, or a sustained data rate achieved during the transmission of the previous data stream over the pre-determined period of time.

15. The method as claimed in claim 11 , wherein estimating the data rate is based at least one of a guaranteed bit rate, or a maximum sustained data rate, or a minimum sustained data rate associated with transmission of the data stream.

16. An apparatus comprising,

a communication interface for providing an interface to a communication link;

a memory for storing a plurality of pre-defined target error rate values and a plurality of pre-defined data rate threshold values, wherein each of the pre-defined target error rate values is mapped to one of the pre-defined data rate threshold values;

a data rate estimator for estimating a data rate associated with transmission of a data stream on a communication link according to a pre-defined communication protocol;

a target error rate controller for selecting a required target error rate from the plurality of pre-defined target error rate values based on whether the estimated data rate is within a range of at least one of the plurality of pre-defined data rate threshold values, and wherein the pre-defined data rate threshold values are selected, and the plurality of pre-defined target error rate values are mapped to the pre-defined data rate threshold values, such that the selected target error rate is higher than a target error rate which the communication protocol specifies for the estimated data rate;

a link adaptation controller for selecting at least one link adaptation parameter associated with the communication link to maintain the required target error rate; and

a transmitter for transmitting the data stream on the communication link using the selected link adaptation parameter.

17. The apparatus as claimed in claim 16 , wherein the data rate estimator

monitors data rate associated with transmission of a previous data stream on the communication link over a pre-determined period of time, and

estimates the data rate based on at least one of a peak data rate, or a maximum data rate, or a sustained data rate achieved during the transmission of the previous data stream over the pre-determined period of time.

18. The apparatus as claimed in claim 16 , wherein the data rate estimator estimates the data rate based on at least one of a guaranteed bit rate, or a maximum sustained data rate, or a minimum sustained data rate associated with transmission of the data stream.

19. The apparatus as claimed in claim 16 , wherein the at least one link adaptation parameter is at least one of a modulation and coding scheme, a transmission power, and an error protection scheme.

20. The apparatus as claimed in claim 16 , wherein the target error rate is at least one of a packet error rate, a frame error rate, and a block error rate.