Cognitive Radio Power Control for TV Interference Reduction
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Solution Overview
Problem
Cognitive Radio Systems (CRS) cause interference to adjacent TV systems due to out-of-band leakage during energy radiation, leading to increased noise floor and reduced receiver sensitivity.
Innovation Solution
A method and device for controlling the power of CRS by measuring system parameters, determining a maximum transmission power, and adjusting the actual transmission power to be less than the maximum, using formulas that consider reception power, interference ratios, and path loss to minimize interference, and employing techniques like increasing filters or spectrum isolation to reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the cognitive radio system transmits at high power to improve communication quality, then the transmission power increases, but out-of-band leakage causes interference to adjacent TV systems
Solution Approach 1:
The patent dynamically adjusts the transmission power parameter of the cognitive radio system based on real-time detection of TV signal presence and strength in adjacent channels. By changing the power parameter adaptively rather than using fixed high power, the system maintains communication quality while preventing harmful interference to TV systems
Solution Approach 2:
The patent implements a feedback mechanism where the cognitive radio system continuously monitors the TV system's reception power and uses this information to adjust its own transmission power. The formula PTX=PRX-TV-RD/U-G+ACIR+max{MCL,PC(d)}-A provides a closed-loop control that automatically reduces power when TV interference is detected and allows higher power when the channel is clear
2Object-affected harmful factors
If the cognitive radio system uses filters or spectrum isolation to reduce out-of-band leakage, then interference to TV systems decreases, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary power control mechanism that mediates between the cognitive radio transmitter and the TV receiver. Rather than adding complex physical filters or isolation structures, the system uses intelligent power adjustment as a virtual intermediary to prevent interference, achieving the same protective effect with simpler means
Solution Approach 2:
The patent changes the operational parameters of the cognitive radio system dynamically based on environmental conditions. By adjusting transmission power according to detected TV signal levels, the system achieves interference reduction without requiring permanent complex filtering hardware, thus avoiding increased device complexity
Data Source
AI summary
The disclosure provides a method and a device for controlling power of a cognitive radio system. The method comprises: measuring a system parameter of a cognitive radio system and a system parameter of a TV system located in an adjacent channel of the cognitive radio system; determining a maximum transmission power of the cognitive radio system according to the system parameter of the cognitive radio system and the system parameter of the TV system; controlling an actual transmission power of the cognitive radio system to be less than the maximum transmission power. In the disclosure, interference to the TV system can be reduced maximally, so that the sensitivity of a receiver inside the TV system is guaranteed.