doc.:IEEE ac Submission Nov 2010 Jun Zheng, BroadcomSlide 1 Legacy CSD Table for 11AC Date: Authors:
doc.:IEEE ac Submission Nov 2010 Summary Propose a methodology to design legacy CSD for 11ac –Minimize the AGC error of the legacy portion of the frame –Minimize the power fluctuation of the post AGC signal Propose to reuse the legacy CSD of n for NTX <= 4 Optimization of legacy CSD for NTX > 5 Propose the final legacy CSD tables for 11ac Slide 2Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Legacy CSD for NTX <= 4 Propose to reuse n legacy CSD for NTX <=4 Slide 3 NTXCSD values 95 percentile of the AGC error of legacy preamble channel model: 11nB/C/D/E 95 percentile of power difference between L-STF & VHT-STF channel model: 11nB/C/D/E 20MHz40MHz80MHz20MHz40MHz80MHz 100.9dB0.6dB0.5dB0dB dB1.1dB0.9dB2.6dB1.7dB1.5dB dB1.4dB1.1dB3.7dB3.0dB2.5dB dB0.9dB0.8dB3.8dB2.9dB2.5dB Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Optimization of Legacy CSD Assume CSDs are multiples of 25ns Assume CSDs are within the range of [-200ns 0ns] Minimize AGC error span of the legacy preamble, i.e. from 2.5% to 97.5% of the AGC error CDF of 11n channel model B/C/D/E In order to capture the random initial phase offset of the TX chain, 2 cases are considered –0 deg phase shift between even and odd TX antennas –180 deg phase shift between even and odd TX antennas Slide 4Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Optimized Legacy CSD for NTX > 4 Observations: –AGC error of the legacy preamble is usually small –Optimal CSD combinations are not unique There are more than one CSD combinations provide close to optimal performance in terms of minimizing the legacy AGC error –Power difference between L-STF and VHT-STF could be large Slide 5 NTXCSD values (units of ns) 95 percentile of the AGC error of legacy preamble channel model: 11nB/C/D/E 95 percentile of power difference between L-STF & VHT-STF channel model: 11nB/C/D/E 20MHz40MHz80MHz20MHz40MHz80MHz dB0.7dB0.5dB10.3dB3.6dB2.9dB dB0.7dB0.5dB6.3dB3.0dB2.1dB dB0.6dB0.5dB5.6dB3.0dB2.4dB dB0.7dB0.5dB7.9dB3.4dB2.7dB Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Further Optimization of Legacy CSD Assume CSDs are multiples of 25ns Assume CSDs are within the range of [-200ns 0ns] Only consider CSD combinations whose AGC error span of the legacy preamble is no greater than 0.1dB of the optimal CSD combination (provide in slide 5) Minimize the 95 percentile of the absolute power difference between L-STF and VHT-STF for 11n channel model B/C/D/E In order to capture the random initial phase offset of the TX chain, 2 cases are considered –0 deg phase shift between even and odd TX antennas –180 deg phase shift between even and odd TX antennas Slide 6Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Further Optimized Legacy CSD for NTX > 4 Slide 7 NTXCSD values 95 percentile of the AGC error of legacy preamble channel model: 11nB/C/D/E 95 percentile of power difference between L-STF & VHT-STF channel model: 11nB/C/D/E 20MHz40MHz80MHz20MHz40MHz80MHz dB0.7dB0.5dB5.6dB2.8dB2.0dB dB0.8dB0.5dB4.4dB2.5dB1.8dB dB0.7dB0.5dB4.8dB2.4dB1.9dB dB0.8dB0.6dB5.2dB2.6dB2.0dB Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Pre-Motion #1 Do you support to use the following CSD table for legacy preamble and add the language provided in Appendix to Clause of the IEEE Specification Framework for TGac ? Slide n Legacy CSD table Jun Zheng, Broadcom
doc.:IEEE ac Submission Nov 2010 Appendix Cyclic shift definition: The cyclic shift values defined in this subclause apply to the L-STF, L-LTF, L- SIG, and VHT-SIG-A of the VHT format legacy preamble. The cyclic shift value for the portion of the packet before VHT-STF for transmitter out of total is shown in the following Table: Slide 9 values for Legacy portion of the packet Total number of transmit antennas (N TX ) Cyclic shift for transmit antenna i TX (in units of ns) Jun Zheng, Broadcom