1 / 11

A FAST SELECTIVE-DIRECTION MMSE TIMING RECOVERY ALGORITHM FOR SPATIAL-TEMPORAL EQUALIZATION IN EDGE

A FAST SELECTIVE-DIRECTION MMSE TIMING RECOVERY ALGORITHM FOR SPATIAL-TEMPORAL EQUALIZATION IN EDGE . Hanks H. Zeng Ye Li Jack H. Winters. AT&T Labs - Research Red Bank, NJ 07701-7033 jhw@research.att.com September 27, 2000. OUTLINE. EDGE Spatial-Temporal equalization

ulfah
Download Presentation

A FAST SELECTIVE-DIRECTION MMSE TIMING RECOVERY ALGORITHM FOR SPATIAL-TEMPORAL EQUALIZATION IN EDGE

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. A FAST SELECTIVE-DIRECTION MMSE TIMING RECOVERY ALGORITHM FOR SPATIAL-TEMPORAL EQUALIZATION IN EDGE Hanks H. Zeng Ye Li Jack H. Winters AT&T Labs - Research Red Bank, NJ 07701-7033 jhw@research.att.com September 27, 2000

  2. OUTLINE • EDGE • Spatial-Temporal equalization • Selective-direction timing recovery • Results • Conclusions

  3. THIRD GENERATION TDMA SYSTEM: EDGE • EDGE: Enhanced Data Rates for Global Evolution • High data rate (384 kbps) service based on GSM, evolution of IS-136 and GSM • 8PSK at 270.833 ksps • 26 symbol training sequence • 1/3, 3/9 or 4/12 reuse • Both ISI and CCI 58 3 8.25 3 26 58 576.92 s

  4. SMART ANTENNAS IN TDMA SYSTEMS • Currently, 2 receive antennas at base stations with IS-136 • Combining changed from maximal ratio to MMSE combining in 1999 => 3-4 dB SINR gain • Planned upgrade to 4 antennas for further improvement • Spatial processing (track channel across time slot) • Want to use smart antenna techniques in EDGE • Spatial-Temporal processing (constant weights across time slot)

  5. SMART ANTENNAS IN EDGE • Spatial-Temporal processing using DDFSE for interference suppression • 5 feedforward taps, 5 feedback taps, 8-state Viterbi Equalizer • Degradation due to shortened equalizer => timing critical

  6. WEIGHT ESTIMATION AND TIMING RECOVERY Previous technique: Weight estimation: Train as MMSE-DFE Timing: MPE - Minimize ratio of precursor to cursor energy Issue: Much poorer performance with strong precursor versus postcursor ISI

  7. WEIGHT ESTIMATION AND TIMING RECOVERY Solution: Selective-direction equalization Since time slot is processed as a block, select either the forward or reverse direction for processing, with timing that minimizes the MMSE (trained as MMSE- DFE).

  8. WEIGHT ESTIMATION AND TIMING RECOVERY Issue: Computational complexity of training is doubled (with two directions) - important since inverse of large matrix is required, which is computationally intensive Solution: As shown in paper, the training algorithm can be modified so that the same matrix inverse is used for both directions => minimal computational-complexity increase with our technique

  9. BER with 2 antennas, HT profile, and single interferer

  10. BLER with single interferer (MCS-5)

  11. CONCLUSIONS Proposed a selective-direction MMSE timing recovery algorithm for ST processing: Improves performance with minimal increase in computational complexity Applied algorithm to EDGE: 3 dB lower SIR for 1% raw BER with 2 antennas as compared to previous technique Up to 25 dB interference suppression at 10% BLER with two antenna versus single antenna receiver

More Related