1 / 15

Detection schemes for transmit diversity with no channel estimation

Detection schemes for transmit diversity with no channel estimation. Advisor : Dr. Wen-Jye Huang Student : Chi-Ting Wu 2004.07.28. Outline. Introduction Review of transmit diversity scheme Detection method Method Ⅰ~ equal energy Method Ⅱ~ all situations Error performance results

channer
Download Presentation

Detection schemes for transmit diversity with no channel estimation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Detection schemes for transmit diversity with no channel estimation Advisor : Dr. Wen-Jye Huang Student : Chi-Ting Wu 2004.07.28

  2. Outline • Introduction • Review of transmit diversity scheme • Detection method • Method Ⅰ~ equal energy • Method Ⅱ~ all situations • Error performance results • Sensitive to time variance • Conclusion

  3. Introduction • Channel condition is needed • Orthogonal pilot sequence in slow fading • Impossible task in real life • In non-coherent detection • Channel estimation is not needed • New transmit diversity scheme

  4. Review of transmit diversity

  5. Review of transmit diversity • After substitution • After ML decision • Choose

  6. Detection method Ⅰ • Assumptions • Flat fading over 4 transmission symbols • Equal energy • Receiver knows first two signals ~pilots

  7. Detection method Ⅰ(cont.) • Two intermediate values • Then

  8. Detection method Ⅰ(cont.) • It may be shown that • Finding the closest points to Known signal computed signal

  9. Detection method Ⅱ • Equal energy assumption is removed according to we get

  10. Detection method Ⅱ (cont.) • Step 1: use to decode • Step 2: once are computed, use the equation above to compute new channel condition • Step 3: decodes for • Step 4: go back to step 1… If the channel is quasi-static, channel estimation can be used at each time

  11. Error performance results 。3dB penalty because of CSI 。in the environment under 13dB, single antenna has better performance 。BLER instead of BER 3dB Error performance of transmit diversity with new detection schemes in Rayleigh Fading

  12. Sensitivity to time variance • To estimate the rate of change in channel, we use • Fade duration should be larger than 4 symbols • Assume in a -40dB fade level

  13. Sensitivity to time variance (cont.) 。as shown in the figure, average fade duration to be larger than 40 symbols, must be smaller than

  14. Conclusion • Diversity order of 2 is obtained • The new detection scheme does not need channel estimation • The scheme performs better when the normalized Doppler frequency is less than

  15. Thank you for your attention ~

More Related