1. An Iterative Optimization Strategy in Multiple Points to Multiple Points MIMO (M4) Mobile Communication Systems MCL Yun-Shen Chang 2006-08-07

2. 2 Motivation  MIMO channels often suffer from the rank- deficiency problem, eg. most outdoor channels., resulting in significant throughput degradation.  The proposed M4 system provides a solution for achieving high spectral efficiency in a less scattered wireless MIMO channel with rank deficient channel matrix.  As opposed to conventional DPC requiring large number of transmit antennas, the M4 system effectively mitigate the limitation by using receive beamformers.

3. 3 The M4 System

4. 4 Notations

5. 5 System Model

6. 6

7. 7 Interference Suppression

8. 8

9. 9 IRB Step 1: MMSE Beamforming

10. 10 IRB Step 2: Channel reconfiguration

11. 11 IRB Step 3: Transmit side ZF

12. 12 IRB Step 4: End of training stage

13. 13 Step 5: Data transmission

14. 14 THP

15. 15 Decoding

16. 16 Example:

17. 17

18. 18 Singular values

19. 19

20. 20 vs.

21. 21

22. 22 Potential research directions  Convergence analysis of IRB  Iteratively updating from  Non-orthogonal signaling with individual SINR constraints