Power control in cognitive radio systems based on spectrum sensing side information
View Patent ↗For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.
1. A method, comprising:
determining, by a computing device including a processor, an average probability of a missing energy detection of a primary transmitter of a primary device based on sensing information associated with a cognitive radio device; and
determining, by the computing device, a distance parameter between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection.
2. The method of claim 1 , further comprising:
controlling, by the computing device, a transmit power of the cognitive radio device based on the distance parameter to meet a quality of service requirement for the primary device.
3. The method of claim 2 , wherein the controlling the transmit power comprises:
determining a maximum transmit power that meets the quality of service requirement based upon a path loss function of the distance parameter; and
limiting the transmit power to the maximum transmit power.
4. The method of claim 1 , wherein the determining the distance parameter comprises:
determining a plurality of candidate distances between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection; and
setting the distance parameter to a shortest distance of the plurality of candidate distances.
5. The method of claim 1 , further comprising:
determining, by the computing device, the sensing information by monitoring energy of a signal received by the cognitive radio device in a predetermined bandwidth for predetermined period of time.
6. A cognitive radio device, comprising:
a spectrum sensing component configured to:
estimate an average probability of a missing energy detection of a primary transmitter of a primary device based on sensing information associated with a cognitive radio device; and
estimate a distance parameter between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection.
7. The cognitive radio device of claim 6 , further comprising:
a power control component configured to adjust a transmit power of the cognitive radio device based on the distance parameter to meet a quality of service requirement for the primary device.
8. The cognitive radio device of claim 7 , wherein the power control component is further configured to:
determine a maximum transmit power that meets the quality of service requirement based upon a path loss function of the distance parameter; and
prevent the transmit power from exceeding the maximum transmit power.
9. The cognitive radio device of claim 6 , wherein the spectrum sensing component is further configured to:
identify a plurality of candidate distances between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection; and
set the distance parameter to a shortest distance of the plurality of candidate distances.
10. The cognitive radio device of claim 6 , wherein the spectrum sensing component is further configured to determine the sensing information by monitoring energy of a signal received by the cognitive radio device in a predetermined spectrum for at least one predetermined time slot.
11. A non-transitory computer readable storage medium comprising computer executable instructions that, in response to execution, cause a device including a processor to perform operations, comprising:
approximating an average probability of a missing energy detection of a primary transmitter of a primary device based on sensing information associated with a cognitive radio device; and
identifying a distance parameter between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection.
12. The non-transitory computer readable storage medium of claim 11 , wherein the operations further comprise modifying a transmit power of the cognitive radio device based on the distance parameter to meet a quality of service requirement for the primary device.
13. The non-transitory computer readable storage medium of claim 12 , wherein the operations further comprise:
identifying a maximum transmit power that meets the quality of service requirement based upon a path loss function of the distance parameter; and
inhibiting the transmit power from exceeding the maximum transmit power.
14. The non-transitory computer readable storage medium of claim 11 , wherein the identifying the distance parameter comprises:
estimating a plurality of candidate distances between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection; and
selecting a distance as a function of a shortest distance of the plurality of candidate distances as the distance parameter.
15. The non-transitory computer readable storage medium of claim 11 , wherein the operations further comprise obtaining the sensing information by monitoring energy of a signal received by the cognitive radio device in a predetermined bandwidth for one or more predetermined time intervals.
16. A system, comprising:
means for calculating an average probability of a missing energy detection of a primary transmitter of a primary device based on sensing information associated with a cognitive radio device; and
means for determining a distance parameter between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection.
17. The system of claim 16 , further comprising:
means for setting a transmit power of the cognitive radio device based on the distance parameter to meet a quality of service requirement for the primary device.
18. The system of claim 17 , further comprising:
means for determining a maximum transmit power that meets the quality of service requirement based upon a path loss function of the distance parameter; and
means for blocking the transmit power from exceeding the maximum transmit power.
19. The system of claim 16 , wherein the means for determining the distance parameter comprises:
means for identifying a plurality of candidate distances between the primary transmitter and the cognitive radio device based upon the average probability of the missing energy detection; and
means for setting the distance parameter to a shortest distance of the plurality of candidate distances.
20. The system of claim 16 , further comprising:
means for determining the sensing information by monitoring energy of a signal received by the cognitive radio device in at least one predetermined spectrum for at least one predetermined time period.