1. Adaptive radio-frequency resource management for MIMO MC-CDMA on antenna selection Jingxu Han and Mqhele E Dlodlo Department of Electrical Engineering University of Cape Town

2. UCT-COE Seminar 000 Page 2 March 10, 2016 What is MIMO?  MIMO (Multiple Input Multiple Output) is a new wireless technology conceived in the mid 90’s  Greatly improves the reliability, range and robustness of existing wireless communication systems  Can provide h igh data rate (channel capacity) high QoS (low bit error rate)  Selected for many standards, such as W-CDMA

3. UCT-COE Seminar 000 Page 3 March 10, 2016 Introduction of MC CDMA  Multi-carriers CDMA (MC CDMA) is a multiple access technology used in wireless communication systems based on OFDM  a strong candidate as an access technique for downlink of broadband cellular systems  Obtains benefits from both MC and CDMA techniques: high spectral efficiency, robustness in frequency selective channels

4. UCT-COE Seminar 000 Page 4 March 10, 2016 Combination of MIMO MC-CDMA systems AA promising technology for 4G wireless communication since: 1 high date rate 2 high Qos 3 multiple users communication 4 high spectral efficiency

5. UCT-COE Seminar 000 Page 5 March 10, 2016 Why antenna selection?  An inherent drawback for multiple antenna system is the increased hardware complexity due to the requirement for radio-frequency chain.  Corresponding to power amplifiers, mixers analog to digital converter ect.  An ideal approach to reduce the complexity of a multiple antennas system while maintaining the advantages

6. UCT-COE Seminar 000 Page 6 March 10, 2016 Ideas behind antenna selection  Choose a subset of best performance antennas either in transmission and/ or reception to feed to the RF chain for signal processing  Existing algorithms:  1) maximum signal to noise ratio  2) maximum channel mean  3) minimum instantaneous probability of error

7. UCT-COE Seminar 000 Page 7 March 10, 2016 Proposing algorithm  An improved low complexity algorithm proposed based on maximum ratio method  the method is simplified to choose the best performance antenna from all the possible antennas, then choose the best performance antenna from the rest possible antennas instead of calculate Frobenius norm for all the possible antennas

8. UCT-COE Seminar 000 Page 8 March 10, 2016 Complexity comparison  For instance: selecting 2 antennas out of 10 antennas  Old algorithm calculation complexity is 45  Correspondingly the novel one is 19

9. UCT-COE Seminar 000 Page 9 March 10, 2016 Adaptive RF management  Aim to flexibly manage RF resource for MIMO MC-CDMA systems based on antenna selection  1) Set target bit error rate  2) find out minimum number of antennas to feed RF need  3) adaptive increasing the number of antennas on increment of users or interferences

10. UCT-COE Seminar 000 Page 10 March 10, 2016 Simulation results

11. UCT-COE Seminar 000 Page 11 March 10, 2016

12. UCT-COE Seminar 000 Page 12 March 10, 2016

13. UCT-COE Seminar 000 Page 13 March 10, 2016

14. UCT-COE Seminar 000 Page 14 March 10, 2016

15. UCT-COE Seminar 000 Page 15 March 10, 2016 Conclusion  A novel transmission adaptive technique for MIMO MC-CDMA system as an aim to flexibly manage radio frequency resource based on antenna selection is presented  The simulation results, depending on both numbers of users and signal to noise ratio (SNR) value, show significant gains compared to fixed systems for a predefined target bit error rate (BER)

16. UCT-COE Seminar 000 Page 16 March 10, 2016 Future work  Performance investigation for the real MIMO channels are needed  Effective feedback path is necessary to insure the system, and performance over fast fading channel is also an interesting topic.

17. Thanks Questions?