1. Follow up on Preamble Design for WUR
Month Year
doc.: IEEE yy/xxxxr0
July 2017
Follow up on Preamble Design for WUR
Date:
Authors:
Name
Affiliation
Address
Phone
Jianhan Liu
Mediatek USA
2840 Junction Ave, San Jose, CA 95134, USA
Tianyu Wu
Thomas Pare
Frank Hsu
Mediatek
Jianhan Liu, Mediatek, et. al.
Hongyuan Zhang, Marvell; etc.

2. Recap of the Preamble Design
July 2017
Recap of the Preamble Design
Proposed WUR packet structure:
AGC/Sync sequence:
Propose OOK modulated ‘ ’ sequence. Power measurement is stable in any measuring window of 2 bit width. AGC adjustment will be accurate and quick.
The sequence also accelerates synchronization by measuring the power within each symbol. The symbol
boundary can be easily detected by
choosing the 4us window with
maximum power.
AGC/Sync Sequence
WUR Signature Sequence
Control Information
WUR preamble part

3. Recap of the Preamble Design – cont’d
July 2017
Recap of the Preamble Design – cont’d
WUR Signature Sequence
Specific OOK modulated sequence. Can be m sequence, Golay sequence or a pseudo-random sequence.
The WUR receiver relies on the detection of WUR signature sequence to claim the WUR packet detection and to find the boundary between preamble and control information.
Propose to use WUR signature sequence to indicate different data rate for WUR packet payload part.
Our design is to introduce multiple signature sequences and each signature sequence indicates one specific data rate.
For example, the data rate of the control information can be 125kbps, 250Kbps or 500kbps. Then 3 different signature sequences with large hamming distance are used. The first signature sequence indicates data rate 125kbps, the second signature sequence indicates 250kbps and the third signature sequence indicates 500kbps.

4. Example AGC/Sync sequence: a number of repetitions of ‘1 0’.
Signature sequence: M sequence
M sequence has following nice properties:
Occurrence of 0 and 1 in the sequence is approximately the same
Autocorrelation function is close to delta function
Large and stable Hamming distance between M sequences. For m sequences of length 15, the Hamming distance is always 8 between any pair of them.
Use three 15bits M sequences to signal 3 different rates, for example:
125k: ‘ ’
256k: ‘ ’
512k: ‘ ’

5. Simulation settings Channel model D-NLOS
Phase noise model follow reference [1].
5th order Butterworth filter
250kbps rate
4Mhz WUR BW
Null GI inserted to avoid ISI

6. July 2017
Simulation results (1)
Longer AGC/SYNC sequence will bring some gain by finding more accurate boundary and better threshold. 8 or 12 bits for AGC/SYNC sequence seems to be a reasonable length for AGC/SYNC sequence.

7. Simulation results (2)
False alarm rate: The probability of detect interference (random OFDM symbols) as target signature sequence. FA rate is slightly above 10-4.

8. Simulation results (3)
Signature sequence error rate: The probability of detecting target signature sequence as a wrong signature sequence. This probability is very low for the SNR range of interest.

9. Conclusion
Suggest 8 or 12 bits AGC/SYNC sequence of OOK modulated ‘1 0’ repetitions
M sequence is a good candidate for signature sequence.
Using different signature sequence to indicate different WUR packet rate is very reliable.

10. July 2017
Straw poll #1
Do you agree to use different signature sequences to indicate different data rates?
Jianhan Liu, Mediatek, et. al.

11. References
[1] 11-17/0326r0 WUR phase noise model - follow-up