POWER CONTROL IN COGNITIVE RADIO SYSTEMS BASED ON SPECTRUM SENSING SIDE INFORMATION
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:
controlling, by a system comprising a processing device, a transmit power of a cognitive radio device using an average probability of a missing energy detection of a primary transmitter of a primary device, wherein the missing energy detection is determined using sensing information associated with the cognitive radio device.
2 . The method of claim 1 , wherein the controlling comprises controlling the transmit power of the cognitive radio device to satisfy a quality of service requirement for the primary device.
3 . The method of claim 1 , further comprising:
determining a distance parameter between the primary transmitter and the cognitive radio device using the average probability of the missing energy detection.
4 . The method of claim 3 , wherein the controlling comprises:
determining a maximum transmit associated with a quality of service requirement of the primary device based on a path loss function of the distance parameter; and
limiting the transmit power to the maximum transmit power.
5 . The method of claim 3 , wherein the determining the distance parameter comprises:
determining a plurality of candidate distances between the primary transmitter and the cognitive radio device using the average probability of the missing energy detection; and
setting the distance parameter to a shortest distance of the plurality of candidate distances.
6 . The method of claim 1 , further comprising:
determining the sensing information by monitoring an energy of a signal received by the cognitive radio device in a predefined bandwidth for a predefined period of time.
7 . A cognitive radio device, comprising:
a memory, coupled to a processing device, that stores computer-executable instructions, comprising:
a control component configured to control a transmit power of a cognitive radio device using an average probability of a missing energy detection of a primary transmitter of a primary, wherein the missing energy detection is determined using sensing information associated with the cognitive radio device.
8 . The cognitive radio device of claim 7 , wherein the control component is configured to control the transmit power of the cognitive radio device to satisfy a quality of service requirement for the primary device
9 . The cognitive radio device of claim 7 , wherein the computer-executable instructions further comprise:
a spectrum sensing component configured to determine a distance parameter between the primary transmitter and the cognitive radio device using the average probability of the missing energy detection.
10 . The cognitive radio device of claim 9 , wherein the control component is further configured to:
determine a maximum transmit power associated with a quality of service requirement using a path loss function of the distance parameter; and
prevent the transmit power from exceeding the maximum transmit power.
11 . The cognitive radio device of claim 9 , wherein the spectrum sensing component is further configured to:
identify a plurality of candidate distances between the primary transmitter and the cognitive radio device using the average probability of the missing energy detection; and
set the distance parameter to a shortest distance of the plurality of candidate distances.
12 . The cognitive radio device of claim 7 , wherein the computer-executable instructions further comprise:
a spectrum sensing component 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.
13 . A computer readable storage device comprising computer executable instructions that, in response to execution, cause a device comprising a processing device to perform operations, comprising:
setting a transmit power of a cognitive radio device based on an average probability of a missing energy detection of a primary transmitter of a primary device, wherein the missing energy detection is based on sensing information associated with the cognitive radio device.
14 . The computer readable storage device of claim 13 , wherein the setting comprises modifying a transmit power of the cognitive radio device based on the distance parameter to satisfy a quality of service requirement for the primary device.
15 . The computer readable storage device of claim 13 , wherein the operations further comprise:
estimating a distance parameter between the primary transmitter and the cognitive radio device based on the average probability of the missing energy detection.
16 . The computer readable storage device of claim 15 , wherein the setting comprises:
identifying a maximum transmit associated a quality of service requirement of the primary device based on a path loss function of the distance parameter.
17 . The computer readable storage device of claim 16 , wherein the setting further comprises:
setting the transmit power to the maximum transmit power.
18 . The computer readable storage device of claim 15 , wherein the estimating comprises:
estimating a plurality of candidate distances between the primary transmitter and the cognitive radio device based on the average probability of the missing energy detection.
19 . The computer readable storage device of claim 18 , wherein the estimating further comprises:
selecting a distance as a function of a shortest distance of the plurality of candidate distances as the distance parameter.
20 . The computer readable storage device of claim 13 , wherein the operations further comprise obtaining the sensing information by monitoring energy of a signal received by the cognitive radio device in a predefined bandwidth for one or more predefined time intervals.