System and method for providing adaptive control of transmit power and data rate in an ad-hoc communication network

• US 6,904,021 B2
• Filed: 03/15/2002
• Issued: 06/07/2005
• Est. Priority Date: 03/15/2002
• Status: Expired due to Term

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: MeshNetworks, Inc. (Motorola Solutions, Inc.)
• Inventors: Belcea, John M.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Nguyen, Van Kim T.
• Application Number:
  US10/087,016
• Publication Number:
  US 20030189906A1
• Time in Patent Office: 1,180 Days
• Field of Search: 370/252, 370/465, 370/318, 370/468, 455/522, 375/377, 375224-226
• US Class Current: 370/252
• CPC Class Codes: H04W 52/22 taking into account previous information or commands
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks

Abstract

A system and method for selecting an appropriate transmit power and data rate at which a communication signal is transmitted over a link between nodes in a wireless ad-hoc communication network based on factors such as variations in path loss in the link, fading conditions, noise level estimation and overall link quality. The system and method perform the operations of computing path loss in the link based on information provided to the source node from the destination node pertaining to characteristics of a message that was transmitted by the source node and received by the destination node, determining a noise factor at the destination node, and calculating the power level and rate at which the data is transmitted over the link from the source node to the destination node based on the path loss and the noise factor. More specifically, the method calculates the power level based on the path loss, the noise factor and signal fading, and determines the rate based on the calculated power level. Furthermore, the path loss is computed dynamically as conditions of said link change over time. Accordingly, the system and method are capable of determining the proper level of transmit power and data rate for assuring that the destination node will receive the data transmitted by the source node at a reliability of at least 90%.

Claims

1. A method for determining at least one of a power level and rate at which data is transmitted over a link between source and destination nodes in a wireless ad-hoc communication network, comprising:

predicting path loss in said link as a function of time based on information provided to said source node from said destination node pertaining to characteristics of at least two messages that were transmitted by said source node for receipt by said destination node;

determining a noise factor representative of noise at said destination node; and

calculating at least one of said power level and rate at which said data is transmitted over said link from said source node to said destination node based on said predicted path loss and said noise factor.

2. A method as claimed in claim 1, wherein:

said calculating includes calculating said power level and said rate.

3. A method as claimed in claim 1, wherein:

said calculating includes calculating said power level based on said predicted path loss and said noise factor, and determining said rate based an said calculated power level.

4. A method as claimed in claim 1, wherein:

said noise factor determining determines said noise factor dynamically based on respective message information provided to said source node from said destination node in response to each of a plurality of said messages transmitted by said source node.

5. A method as claimed in claim 4, wherein said noise factor determining comprises:

increasing or decreasing an estimated noise factor based on each said respective message information for said plurality of messages to realize said noise factor.

6. A method as claimed in claim 1, wherein:

said calculating includes calculating at least one of said power level and said rate based on said predicted path loss, said noise factor, short term fading experienced by said message and sensitivity of a receiver of said destination node.

7. A method as claimed in claim 6, further comprising:

computing said short term fading based on a standard deviation of a strength at which said message is received by said receiver of said destination node.

8. A method as claimed in claim 6, further comprising:

computing said receiver sensitivity based on energy used by a transmitter of said source node to transmit a bit of information of said message at a particular data rate.

9. A method as claimed in claim 1, wherein:

said noise factor determining determines said noise factor based on a level of correctness at which a receiver of said destination node receives said message.

10. A method as claimed in claim 1, further comprising:

calculating a quality of a link over which said message is sent from said source node to said destination node based on said calculated power level and said rate.

11. A method as claimed in claim 1, wherein:

said calculating calculates said data rate based on an amount of energy used by a transmitter of said source node to transmit a bit of information of said message.

31. A method as claimed in claim 1, wherein:

said predicting step employs a forget factor which treats older said information less significantly than newer said information in predicting said path loss.

32. A method as claimed in claim 31, wherein:

said predicting step applies a respective value of said forget factor to each respective said information representing the characteristics of a respective message, to weigh said information in predicting said path loss.

33. A method as claimed in claim 32, wherein:

each said respective forget factor value has a value between 0 and 1.

37. A method as claimed in claim 1, wherein:

the calculating calculates the transmit power level and data rate to minimize an amount of energy used for transmitting said data over said link.

12. A computer-readable medium of instructions, adapted to determining at least one of a power level and rate at which data is transmitted over a link between source and destination nodes in a wireless ad-hoc communication network, said instructions comprising:

a first set of instructions, adapted to predict path loss in said link as a function of time based on information provided to said source node from said destination node pertaining to characteristics of at least two messages that were transmitted by said source node for receipt by said destination node;

a second set of instructions, adapted to determine a noise factor representative of noise at said destination node; and

a third set of instructions, adapted to calculate at least one of said power level and rate at which said data is transmitted over said link from said source node to said destination node based on said predicted path loss and said noise factor.

13. A computer-readable medium of instructions as claimed in claim 12, wherein:

said third set of instructions is adapted to calculate said power level and said rate.

14. A computer-readable medium of instructions as claimed in claim 12, wherein:

said third set of instructions is adapted to calculate said power level based on said predicted path loss and said noise factor, and to determine said rate based on said calculated power level.

15. A computer-readable medium of instructions as claimed in claim 12, wherein:

said second set of instructions is adapted to determine said noise factor dynamically based on respective message information provided to said source node from said destination node in response to each of a plurality of said messages transmitted by said source node.

16. A computer-readable medium of instructions as claimed in claim 15, wherein:

said second set of instructions is adapted to increase or decrease an estimated noise factor based on each said respective message information for said plurality of messages to realize said noise factor.

17. A computer-readable medium of instructions as claimed in claim 12, wherein:

said third set of instructions is further adapted to calculate at least one of said power level and said rate based on said predicted path loss, said noise factor, short term fading experienced by said message and sensitivity of a receiver of said destination node.

18. A computer-readable medium of instructions as claimed in claim 17, further comprising:

a fourth set of instructions, adapted to compute said short term fading based on a standard deviation of a strength at which said message is received by said receiver of said destination node.

19. A computer-readable medium of instructions as claimed in claim 17, further comprising:

a fifth set of instructions, adapted to compute said receiver sensitivity based on energy used by a transmitter of said source node to transmit a bit of information of said message at a particular data rate.

20. A computer-readable medium of instructions as claimed in claim 12, wherein:

said second set of instructions is adapted to determine said noise factor based on a level of correctness at which a receiver of said destination node receives said message.

21. A computer-readable medium of instructions as claimed in claim 12, further comprising:

a fifth set of instructions, adapted to calculate a quality of a link over which said message is sent from said source node to said destination node based on said calculated power level and said rate.

22. A computer-readable medium of instructions as claimed in claim 12, wherein:

said third set of instructions calculates said data rate based on an amount of energy used by a transmitter of said source node to transmit a bit of information of said message.

34. A computer-readable medium of instructions as claimed in claim 12, wherein:

said first set of instructions employs a forget factor which treats older said information less significantly than newer said information in predicting said path loss.

35. A computer-readable medium of instructions as claimed in claim 34, wherein:

said first set of instructions applies a respective value of said forget factor to each respective said information representing the characteristics of a respective message, to weigh said information in predicting said path loss.

36. A computer-readable medium of instructions as claimed in claim 35, wherein:

each said respective forget factor value has a value between 0 and 1.

38. A computer-readable medium of instructions as claimed in claim 12, wherein:

said third set of instructions calculates the transmit power level and data rate to minimize an amount of energy used for transmitting said data over said link.

23. A method for determining at least one of a power level and rate at which data is transmitted over a link between source and destination nodes in a wireless ad-hoc communication network, comprising:

computing path loss in said link based on information provided to said source node from said destination node pertaining to characteristics of a message that was transmitted by said source node for receipt by said destination node;

determining a noise factor representative of noise at said destination node; and

calculating at least one of said power level and rate at which said data is transmitted over said link from said source node to said destination node based on said path loss, said noise factor, short term fading experienced by said message and sensitivity of a receiver of said destination node.

24. A method as claimed in claim 23, further comprising:

computing said short term fading based on a standard deviation of a strength at which said message is received by said receiver of said destination node.

25. A method as claimed in claim 23, further comprising:

computing said receiver sensitivity based on energy used by a transmitter of said source node to transmit a bit of information of said message at a particular data rate.

26. A method for determining at least one of a power level and rate at which data is transmitted over a link between source and destination nodes in a wireless ad-hoc communication network, comprising:

computing path loss in said link based on information provided to said source node from said destination node pertaining to characteristics of a message that was transmitted by said source node for receipt by said destination node;

determining a noise factor representative of noise at said destination node; and

calculating at least one of said power level and rate at which said data is transmitted over said link from said source node to said destination node based on said path loss and said noise factor, such that said data rate is calculated based on an amount of energy used by a transmitter of said source node to transmit a bit of information of said message.

27. A computer-readable medium of instructions, adapted to determining at least one of a power level and rate at which data is transmitted over a link between source and destination nodes in a wireless ad-hoc communication network, said instructions comprising:

a first set of instructions, adapted to compute path loss in said link based on information provided to said source node from said destination node pertaining to characteristics of a message that was transmitted by said source node for receipt by said destination node;

a second set of instructions, adapted to determine a noise factor representative of noise at said destination node; and

a third set of instructions, adapted to calculate at least one of said power level and rate at which said data is transmitted over said link from said source node to said destination node based on said path loss, said noise factor, short term fading experienced by said message and sensitivity of a receiver of said destination node.

28. A computer-readable medium of instructions as claimed in claim 27, further comprising:

a fourth set of instructions, adapted to compute said short term fading based on a standard deviation of a strength at which said message is received by said receiver of said destination node.

29. A computer-readable medium of instructions as claimed in claim 27, further comprising:

a fifth set of instructions, adapted to compute said receiver sensitivity based on energy used by a transmitter of said source node to transmit a bit of information of said message at a particular data rate.

30. A computer-readable medium of instructions, adapted to determining at least one of a power level and rate at which data is transmitted over a link between source and destination nodes in a wireless ad-hoc communication network, said instructions comprising:

a first set of instructions, adapted to compute path loss in said link based on information provided to said source node from said destination node pertaining to characteristics of a message that was transmitted by said source node for receipt by said destination node;

a second set of instructions, adapted to determine a noise factor representative of noise at said destination node; and

a third set of instructions, adapted to calculate at least one of said power level and rate at which said data is transmitted over said link from said source node to said destination node based on said path loss and said noise factor, such that said data rate is calculated based on an amount of energy used by a transmitter of said source node to transmit a bit of information of said message.