Pilot Signal Power Control for Cognitive Radio Networks
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Solution Overview
Problem
Cognitive radio technologies face challenges in efficiently managing pilot signal power, leading to interference between primary and secondary networks due to inadequate channel capacity and sensing probability, which affects the availability and utilization of frequency resources.
Innovation Solution
A pilot signal power control apparatus and method that estimates noise increase and sensing probability, calculates channel capacity, and determines optimal pilot signal power to maximize channel capacity and data transmission rate, using a prediction unit, channel capacity calculation unit, and power level determination unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power of the pilot signal is increased to improve sensing probability, then the secondary network can better detect primary network usage, but the power available for the data signal decreases, reducing channel capacity
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the pilot signal power level based on calculated optimal values. The system computes the optimal pilot power that maximizes channel capacity while ensuring adequate sensing probability, then applies this parameter change to the transmission system. This resolves the contradiction by finding the precise parameter value that balances both requirements rather than using fixed high or low power levels.
Solution Approach 2:
The patent implements dynamics by making the pilot signal power adaptive rather than static. The system continuously monitors channel conditions, recalculates the optimal power level based on current noise increase and sensing probability requirements, and adjusts the pilot power dynamically. This allows the system to respond to changing conditions and optimize the trade-off between sensing reliability and data transmission capacity in real-time.
2Productivity
If the power of the pilot signal is decreased to increase data signal power, then channel capacity may improve, but the secondary network cannot recognize primary network usage, causing signal collisions
Solution Approach 1:
The patent applies feedback by establishing a closed-loop control system. The system calculates the optimal pilot power based on channel capacity requirements and sensing probability constraints, applies this power level, and then uses the resulting channel conditions to recalculate and adjust the power level iteratively. This feedback mechanism ensures that the pilot power remains at the optimal balance point, preventing both excessive power waste and insufficient sensing detection.
Solution Approach 2:
The patent implements preliminary action by pre-calculating the optimal pilot power level before transmission based on predicted noise increase and required sensing probability. Rather than reacting to collisions or insufficient sensing after they occur, the system proactively determines the appropriate power level in advance, preventing these problems before they arise while maximizing channel capacity from the outset.
3Reliability
If noise increase due to channel estimation error is reduced, then primary user communication reliability improves, but this requires higher pilot signal power which reduces data signal power
Solution Approach 1:
The patent applies parameter changes by optimizing the pilot-to-data power ratio rather than simply increasing or decreasing pilot power in isolation. The system calculates the specific parameter value for pilot power that achieves the required channel estimation accuracy while minimizing the impact on data signal power. This precise parameter optimization resolves the contradiction by finding the exact balance point where channel estimation reliability is sufficient without unnecessarily sacrificing data transmission capacity.
Data Source
AI summary
A pilot signal power control apparatus to determine a power level of a pilot signal of a primary network to indicate an availability of a wireless resource of thereof to a secondary user of a secondary network according to a cognitive radio technology, the pilot signal power control apparatus and an operation method thereof, the pilot signal power control apparatus including: a prediction unit to predict a noise increase and/or a sensing probability, the noise increase occurring in a primary user of the primary network due to a channel estimation error, and the sensing probability being a probability that a secondary user senses the pilot signal of; a channel capacity calculation unit to calculate a channel capacity of the primary user based on the predicted noise increase and/or sensing probability; and a power level determination unit to determine the power level of the pilot signal using the calculated channel capacity.