MAC protocol with duty-cycle limitation for portable devices in a wireless Ad-Hoc communication network and a method for using the same

• US 20030228875A1
• Filed: 12/16/2002
• Published: 12/11/2003
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Bison Patent Licensing, LLC
• Original Assignee: MeshNetworks, Inc. (Motorola Solutions, Inc.)
• Inventors: Alapuranen, Pertti O.
• Granted Patent: US 7,610,027 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/28 using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 80/02 Data link layer protocols
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A system and method for medium access control (MAC) protocol which controls transmissions in wireless devices to at least substantially comply with specific absorption rate (SAR) limits. The system and method of MAC protocol uses “source-based” time averaging measurements of transmitter “on-times” and an integral of transmission power to direct transmitter duty-cycle such that SAR limits are met. The system and method monitors and controls topology-dependent functions of a node transceiver, including transceiver duty cycle, transceiver transmit power levels and transceiver power-time products, using a automatic transmission control protocol (ATP) to vary functions to maintain specific absorption rate (SAR) limits for handheld and portable devices which are used close to human bodies. In cases in which SAR limits are approached, the ATP can direct the transceiver at the device to adjust each function, or combination of functions, to maintain an acceptable SAR limit.

Claims

1. A method for controlling transmissions at a wireless node to at least substantially comply with specific absorption rate (SAR) limits for said node in a communications network, said network including a plurality of nodes being adapted to transmit and receive signals to and from other nodes in said network, the method comprising:

measuring at least one of a topology-dependent function including transceiver duty cycle, transceiver transmit power integral and transceiver power-time product for at least one node of said network, said at least one node including a media access control controlling said topology-dependent functions; and

controlling a specific absorption rate value for said at least one node by varying at least one of said topology-dependent functions including said duty cycle, transmit power integral and power-time product in at least one time interval over which said specific absorption rate value is determined.

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

measuring said duty cycle of said at least one node determines a percentage of time a transceiver at said at least one node is transmitting per said time interval.

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

measuring said transmit power integral of said at least one node determines an average transmit power level of a transceiver at said at least one node per said time interval.

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

measuring said power-time product of said at least one node determines a total transmit power per said time interval of a transceiver at said at least one node.

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

controlling said specific absorption rate value for said at least one node by varying said duty cycle to adjust a percentage of time a transceiver at said at least one node is transmitting per said time interval.

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

controlling said specific absorption rate value for said at least one node by varying said transmit power integral to adjust an average transmit power level of a transceiver at said at least one node per said time interval.

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

controlling said specific absorption rate value for said at least one node by varying said power-time product to adjust a total transmit power per said time interval of a transceiver at said at least one node.

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

controlling said specific absorption rate value for said at least one node by varying at least one of a modem data rate and spreading factor at said at least one node.

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

varying at least one of a modem data rate and spreading factor at said at least one node by increasing said spreading factor and lowering said transmission power at a transceiver at said at least one node.

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

prioritizing data traffic between nodes of said network based on said power-time product of said at least one node.

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

varying said at least one of said topology-dependent functions via an adaptive transmission protocol of said media access control.

12. A system for controlling transmissions at a wireless node to at least substantially comply with specific absorption rate (SAR) limits for said node in a communications network, said network including a plurality of nodes being adapted to transmit and receive signals to and from other nodes in said network, the system comprising:

a first node, adapted to measure at least one of a topology-dependent function including transceiver duty cycle, transceiver transmit power integral and transceiver power-time product for at least one node of said network, said at least one node including a media access control controlling said topology-dependent functions; and

said first node being further adapted to control a specific absorption rate value for said at least one node by varying at least one of said topology-dependent functions including said duty cycle, transmit power integral and power-time product in at least one time interval over which said specific absorption rate value is determined.

13. A system as claimed in claim 12, wherein:

said first node is adapted to measure said duty cycle of said at least one node to determine a percentage of time a transceiver at said at least one node is transmitting per said time interval.

14. A system as claimed in claim 12, wherein:

said first node is adapted to measure said transmit power integral of said at least one node to determine an average transmit power level of a transceiver at said at least one node per said time interval.

15. A system as claimed in claim 12, wherein:

said first node is adapted to measure said power-time product of said at least one node to determine a total transmit power per said time interval of a transceiver at said at least one node.

16. A system as claimed in claim 12, wherein:

said first node is adapted to control said specific absorption rate value for said at least one node by varying said duty cycle to adjust a percentage of time a transceiver at said at least one node is transmitting per said time interval.

17. A system as claimed in claim 12, wherein:

said first node is adapted to control said specific absorption rate value for said at least one node by varying said transmit power integral to adjust an average transmit power level of a transceiver at said at least one node per said time interval.

18. A system as claimed in claim 12, wherein:

said first node is adapted to control said specific absorption rate value for said at least one node by varying said power-time product to adjust a total transmit power per said time interval of a transceiver at said at least one node.

19. A system as claimed in claim 12, wherein:

said first node is further adapted to control said specific absorption rate value for said at least one node by varying at least one of a modem data rate and spreading factor at said at least one node.

20. A system as claimed in claim 19, wherein:

said first node is adapted to vary at least one of a modem data rate and spreading factor at said at least one node by increasing said spreading factor and lowering said transmission power at a transceiver at said at least one node.

21. A system as claimed in claim 12, wherein:

said first node is adapted to prioritize data traffic between nodes of said network based on said power-time product of said at least one node.

22. A system as claimed in claim 12, further comprising:

said first node is adapted to vary said at least one of said topology-dependent functions via an adaptive transmission protocol of said media access control.

23. A computer-readable medium of instructions, adapted to control transmissions at a wireless node to at least substantially comply with specific absorption rate (SAR) limits for said node in a communications network, said network including a plurality of nodes being adapted to transmit and receive signals to and from other nodes in said network, comprising:

a first set of instructions, adapted to measure at least one of a topology-dependent function including transceiver duty cycle, transceiver transmit power integral and transceiver power-time product for at least one node of said network, said at least one node including a media access control for executing said first set of instructions to measure said topology-dependent functions, and a second set of instructions to control said topology-dependent functions; and

said second set of instructions, adapted to control a specific absorption rate value for said at least one node by varying at least one of said topology-dependent functions including said duty cycle, transmit power integral and power-time product in at least one time interval over which said specific absorption rate value is determined.

24. A computer-readable medium of instructions as claimed in claim 23, wherein:

said first set of instructions is adapted to measure said duty cycle of said at least one node to determine a percentage of time a transceiver at said at least one node is transmitting per said time interval.

25. A computer-readable medium of instructions as claimed in claim 23, wherein:

said first set of instructions is adapted to measure said transmit power integral of said at least one node to determine an average transmit power level of a transceiver at said at least one node per said time interval.

26. A computer-readable medium of instructions as claimed in claim 23, wherein:

said first set of instructions is adapted to measure said power-time product of said at least one node to determine a total transmit power per said time interval of a transceiver at said at least one node.

27. A computer-readable medium of instructions as claimed in claim 23, wherein:

said second set of instructions is adapted to control said specific absorption rate value for said at least one node by varying said duty cycle to adjust a percentage of time a transceiver at said at least one node is transmitting per said time interval.

28. A computer-readable medium of instructions as claimed in claim 23, wherein:

said second set of instructions is adapted to control said specific absorption rate value for said at least one node by varying said transmit power integral to adjust an average transmit power level of a transceiver at said at least one node per said time interval.

29. A computer-readable medium of instructions as claimed in claim 23, wherein:

said second set of instructions is adapted to control said specific absorption rate value for said at least one node by varying said power-time product to adjust a total transmit power per said time interval of a transceiver at said at least one node.

30. A computer-readable medium of instructions as claimed in claim 23, further comprising:

a third set of instructions, adapted to control said specific absorption rate value for said at least one node by varying at least one of a modem data rate and spreading factor at said at least one node.

31. A computer-readable medium of instructions as claimed in claim 30, wherein:

said third set of instructions is adapted to vary at least one of a modem data rate and spreading factor at said at least one node by increasing said spreading factor and lowering said transmission power at a transceiver at said at least one node.

32. A computer-readable medium of instructions as claimed in claim 23, further comprising:

a fourth set of instructions, adapted to prioritize data traffic between nodes of said network based on said power-time product of said at least one node.

33. A computer-readable medium of instructions as claimed in claim 23, wherein:

varying said at least one of said topology-dependent functions is achieved via an adaptive transmission protocol of said media access control.