Adaptive Transmit Power for SIC Receiver Interference
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Solution Overview
Problem
Existing SIC MUD receivers perform poorly when the interfering signal strength is similar to that of the signal of interest, as they struggle to demodulate the raw channel bits correctly, especially when the interfering signal's rate results in a 0 dB SINR, making it impossible to maintain reliable communication.
Innovation Solution
The method involves allowing different wireless networks and radios to coexist in the same frequency band by intentionally causing interference, using sequential interference cancellation (SIC) techniques to mitigate interference without the need for pre-specified coordination or spread spectrum, by adjusting transmit power, coding rate, and modulation levels to optimize signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SIC MUD receiver uses conventional demodulation techniques, then it can process signals in crowded spectrum, but it fails when interfering signal strength is similar to signal of interest strength
Solution Approach 1:
The patent changes the power parameter of the interfering signal by adjusting transmit power levels. The SIC MUD receiver relies on power differences to successfully cancel interference. By controlling transmit power, the system ensures that interfering signals are sufficiently stronger than the signal of interest, enabling reliable demodulation and interference cancellation in crowded spectrum environments.
2Power
If radios transmit at high power to overcome interference, then signal strength increases, but interference to other users increases
Solution Approach 1:
The patent applies local quality by allowing different transmit power levels for different spatial locations and user pairs. The system adjusts transmit power locally based on the specific interference conditions and SIC MUD receiver capabilities of each link, rather than using a uniform power level across all transmissions. This enables high power where needed for reliable communication while minimizing interference to other users.
Solution Approach 2:
The patent implements dynamic transmit power adjustment based on real-time channel conditions, interference levels, and SIC MUD receiver performance. The system continuously adapts power levels to maintain reliable communication while minimizing harmful interference, rather than using fixed power settings.
3Productivity
If multiple wireless networks share the same frequency band, then spectrum utilization increases, but signal interference increases
Solution Approach 1:
The patent converts the harmful effect of interference into a beneficial feature by using SIC MUD reception. Instead of trying to avoid or eliminate interference, the system deliberately allows multiple networks to share the frequency band and uses the interfering signals as input to the SIC MUD receiver, which cancels them out to recover the desired signal. This transforms interference from a harmful factor into an enabled feature for high spectrum utilization.
Data Source
AI summary
In some embodiments, a method for mitigating interference in a channel having multiple users includes: transmitting, by a transmitter, a signal of interest (SOI) to a sequential interference cancellation (SIC) receiver at a transmit power; determining a packet drop rate as seen by the receiver; and decreasing the transmit power in response to determining the packet drop rate exceeds a predetermined maximum packet drop rate. The transmitter's coding rate and/or modulation level may also be lowered based on the decrease in transmit power.