1. Can they transmit simultaneously
Linghe KONG

2. OUTLINE How I got this idea? What’s it? Why to research it? Solution I
Solution II
Some other possible methods
Further works

3. How I got this idea
Exposed & hidden terminal problem

4. How I got this idea
Can the exposed terminals transmit simultaneously

5. What’s it?
Not only the exposed terminal, but more transmit simultaneously…

6. Why to research it? Increase the spatial reuse
Improve the network throughput
Reduce the collision
Less waiting, transmit simultaneously …

7. Solution I Spectrum Cognitive Radio + Multi-Channel Channel 1

8. Solution I
Using cognitive radio to design a smart mechanism maybe hard to implement
Sense delay
Trade-off between the number of channels and the bandwidth
Multicast case

9. Solution II Directional antennas B A B A A B A B Dir TX, Omni RX
Omni TX, Omni RX
Dir TX, Dir RX
Omni TX, Dir RX

10. Solution II
Ask some other free nodes as relay

11. Solution II Scheduling in Large scale nodes environment
Partial tight density, partial loose and maybe cluster-distributing in real case
Complex to schedule the relay nodes

12. Some other possible methods
Coding
Network coding

13. Some other possible methods
Obviously, network coding is not suitable in this situation, but we can borrow this conception and do more advanced work to solve our problem.

14. Further works How about multi-cast, any-cast?
If the nodes could mobile…?
With MPR (Multiple-Packet Reception) technology what will happen?

15. Thanks
Q&A