MIMO OFDM

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This presentation makes note of different techniques present with respect to MIMO OFDM and which can be implemented to improve the wireless system.

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MIMO OFDM

  1. 1. MIMO-OFDM OVERVIEW OF MIMO AND USE OF DIFFERENT TECHNIQUES TO IMPROVE WIRELESS COMMUNICATION USING MIMO By: Darshan Patil, B.E Electronics and Telecommunications, LTCOE
  2. 2. Significance & Introduction of MIMO-OFDM <ul><li>Ever-increasing demands in communication industry towards wireless </li></ul><ul><li>Challenges: </li></ul><ul><li>- to improve spectral efficiency </li></ul><ul><li>- efficient bandwidth utilization </li></ul><ul><li>- economical Signal Processing </li></ul><ul><li>algorithms </li></ul><ul><li>- high speed processing h/w </li></ul><ul><li>Solution: MIMO-OFDM </li></ul>Laptop mimo antenna prototype
  3. 3. Problem statement: <ul><li>To build a prototype of Next genx wireless WAN’s with MIMO-OFDM system using set of algorithms and techniques to analyze the performance and replicate it as a practical implementation through simulations. </li></ul>
  4. 4. Scope of the project <ul><li>Coupling MIMO and OFDM concepts to improve data rates in downlink of wireless communication networks. </li></ul><ul><li>Analyzing the performance and building a prototype of Wireless WAN’S using MIMO-OFDM </li></ul><ul><li>Use of adaptive loading algorithms such as Chows and Compello’s. </li></ul><ul><li>Employing SVD (singular value decomposition) method to increase the performance incase of MIMO </li></ul>
  5. 5. Literature survey and R&D
  6. 6. 1)MIMO concept overview <ul><li>Multiple i/p multiple o/p antenna array </li></ul><ul><li>Used to increase data rates, improve capacity and BER (bit error rate) of the system </li></ul><ul><li>Typically used with ofdm so as to suit best needs in next genx comm. i.e. “4G” </li></ul>Diagram of a MIMO wireless transmission system.
  7. 7. 2) OFDM concept overview <ul><li>- Converts a frequency selective channel into a parallel collection of frequency flat sub channels </li></ul><ul><li>Orthogonal frequency division multiplexing uses bandwidth efficiently </li></ul><ul><li>Improves multipath fading issues </li></ul><ul><li>Reduces the effect of ISI (inter-sub carrier interference) </li></ul>OFDM System block Diagram
  8. 8. 3) Adaptive algorithms and SVD method <ul><li>good sub carriers with high channel power gain are made to carry more bits and/or be allocated with less transmission power, and vice versa for the weak sub carriers. </li></ul><ul><li>Two algorithms :- </li></ul><ul><li>Chows : </li></ul><ul><li>Campellos optimum discrete loading algorithm : </li></ul><ul><li>SVD: method used to overcome sub channel interference, to allocate transmitted Bit/Power through sub channels in an optimum manner. </li></ul>
  9. 9. Technologies needed <ul><li>STTD (space time transmit diversity) </li></ul><ul><li>SM (spatial multiplexing) </li></ul><ul><li>AMC (adaptive modulation & coding) with modulation techniques such as QPSK, 16-QAM, 64-QAM </li></ul><ul><li>H-ARQ (Hybrid automatic repeat request) </li></ul><ul><li>Shared access and MAC (medium access control) used for scheduling packet access with Qos </li></ul>
  10. 10. Comparison of technologies
  11. 11. Antenna & types <ul><li>Multibeam MIMO antenna with 3 beams/ sector and 3 sectors/cell </li></ul><ul><li>Full frequency Reuse concept across cells </li></ul>
  12. 12. Equipments <ul><li>Modem TMS 320c6x digital signal processor </li></ul><ul><li>Power PC TM processor </li></ul><ul><li>MAC and controller kit </li></ul><ul><li>High end D/A converters </li></ul><ul><li>RF and power amplifiers </li></ul><ul><li>Turbo decoder IC </li></ul>
  13. 13. Implementation and simulation <ul><li>Architectures </li></ul><ul><li>Node B prototype hardware architecture </li></ul><ul><li>UE prototype hardware architecture </li></ul>
  14. 14. Simulation results <ul><li>Prototype is helpful in Indoor/indoor application rather than outdoor/indoor </li></ul><ul><li>RF channel replicators are used to create the correlation between outdoor/indoor and indoor/indoor </li></ul>
  15. 15. Project Activities <ul><li>Survey, Implementation and performance analysis of existing MIMO </li></ul><ul><li>Learning s/w and h/w </li></ul><ul><li>Developing efficient algorithms </li></ul><ul><li>Software synchronization development </li></ul><ul><li>Various candidate coding and receiver strategies </li></ul><ul><li>Identification of Equipment </li></ul><ul><li>Implementation of prototype </li></ul>
  16. 16. Project Schedule
  17. 17. Conclusion <ul><li>The results obtained from these tests indicate very good performance for the MIMO-OFDM prototype. </li></ul><ul><li>Concept is proving to be very robust in highly dispersive channels </li></ul><ul><li>Cost reduction is being investigated through various methods </li></ul><ul><li>Simulation results show that at any given BER the adaptive SISO system will be outperformed by the adaptive MIMO system </li></ul><ul><li>Other future work areas involve the improvement of MIMO processing complexity and practical implementation issues. </li></ul>
  18. 18. THANK YOU!!

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