1. Blind Known Interference Cancellation
Zhang Shengli (Shenzhen University)
Good morning every one, I am happy to have this opportunisty to share my latest research result. Blind known interference cancellation. This paper has been accpeted by JSAC with minor revision and it can be accessed on Arxiv.

2. Background Analog network coding
Software defined radio help us find new research problems
Most of us believed that Analog network coding is simple to implement. When we try to implement ANC, However, we found that it is not a easy task. The Qustion is how to cancel the known interference at the end node. We then decided to work on it.

3. Known Interference Successive interference cancellation Relay networks
Over hearing
Then we made a simple survey and found that known interference does exist in many wireless systems. The most famous example is the successive interference cancellation. In SIC, we fist detect one layer signal. Now, this layer signal becomes the known interference and need to be cancelled from the received signals. In one way relay channel, the signal transmitted by the relay is known, is interference to the source. In some Ad hoc networks, some node can overhear other link’s transmission and the overheared packet may help to change later interference to known interference.
Our survey found that there is no satisfactory solutions for this problem.

4. Traditional Cancellation
Two Steps:
Interfering channel estimation
Subtracting Interference
Obstacle: channel estimation
Cooperation design in ANC paper
Cooperation cost
Direct estimation with interference
Bad performance
Non-coherent detection
3dB performance loss

5. BKIC(1)
We then proposed a new algorithm, Blind known interference cancellation. Consider a general receiver, the BKIC module may be inserted as in the figure.

6. BKIC(2) Step 1: Step 2 (critical step):
For BKIC module, the processing includes two steps. In the first step, we cancel the interference based on the fact that the channel between adjacent symbols is almost the same. We use a weighted sum to cancel the interference. The first step looks simple. The most critical step in BKIC is the second step to recover the target signal from the interference-free signal.

7. Recovering Scheme1 Straightforward way
Equivalent to traditional cancellation

8. Recovering Scheme2
Real-valued BP

9. Multipath Case
Scheme 1: cancel all the paths of the interference with complex RBP in one cycle
To be done
Scheme2: cancel each path one by one

10. Performance
Flat fading

11. Performance
Flat fading

12. Performance
Time selective fading

13. Performance
Frequency selective fading

14. Performance
Frequency selective fading

15. Conclusion and Future Work
BKIC is a novel algorithm for a mature problem
It’s of great practical interest and it also needs more theoretical study
In the future, we may focus on its application in different areas and its implementation with SDR.