1. On the Performance of Timing Synchronization and OOK Pulse Bandwidth
Month Year
doc.: IEEE yy/xxxxr0
January 2017
On the Performance of Timing Synchronization and OOK Pulse Bandwidth
Date:
Authors:
Name
Affiliation
Address
Phone
Eunsung Park
LG Electronics
19, Yangjae-daero 11gil, Seocho-gu, Seoul , Korea
Dongguk Lim
Sunwoong Yun
Kiseon Ryu
Jinsoo Choi
HanGyu Cho
Eunsung Park, LG Electronics
John Doe, Some Company

2. January 2017
Overview
In this contribution, we deal with the timing synchronization and the OOK pulse bandwidth and show some performance results to provide insights on them
To this end, we first go through several assumptions such as
Wake-up frame structure
OOK symbol computation
Then, we investigate possible options of the wake-up preamble part for the timing synchronization
Finally, we compare the PER performance among them considering various OOK pulse bandwidths, i.e., the number of available subcarriers, k
Eunsung Park, LG Electronics

3. January 2017
Wake-Up Frame
We assume that the wake-up frame consists of wake-up preamble and wake-up payload
Wake-up preamble further falls into two parts, and the purpose of each part is
Detection and timing synchronization
Signal power measure for calculating a threshold used for decoding and transmission for short control information
Wake-up payload conveys control information
Except for the first preamble part, i.e., the preamble part for the detection and timing synchronization, the wake-up frame is computed by utilizing the OOK symbol as shown in the next slide
The signal structure for the first preamble part is different according to the option as depicted in slide 5 and 6
Wake-up payload
Wake-up preamble
Control information
Detection
& Synch.
Signal power measure &
Short control information
Eunsung Park, LG Electronics

4. January 2017
OOK Symbol
In this contribution, several OOK pulse bandwidths are considered such as 4MHz (k=13), 5MHz (k=16), 8MHz (k=26) and 10MHz (k=32)
As shown in the PER performance for the perfect synchronization in Appendix A, the performance of 1% PER is enhanced as k increases but it no longer gets better when k is larger than 26
Also, the larger bandwidth OOK symbol has, the more power receiver consumes
LNA consumes more power for the signal which utilizes larger bandwidth
On the other hand, in [2], the case of k=1 has a poor performance
Also, the less bandwidth OOK symbol has, the sharper filter receiver requires
Thus, in this contribution, we do not consider the pulse bandwidth larger than 10MHz or less than 4MHz and just deal with the above candidates for simplicity
Also, for the ON-symbol, the frequency domain sequence optimized (or sub-optimized) in terms of the PAPR is applied to each pulse bandwidth
Similar to [1], OOK symbol is generated using OFDM transmitter
Eunsung Park, LG Electronics

5. Preamble Part for Timing Synchronization
January 2017
Preamble Part for Timing Synchronization
We have three options
Option 1 : OOK symbol based signal
It is composed of several OOK symbols which are also used in the other parts
The transmitter just needs to be capable of generating the OOK symbols
Option 2 : Periodic signal in the time domain
Similar to the legacy STF, it is composed of a periodic signal which has a period less than 3.2us
In this contribution, by using an approach similar to generating Manchester coding based signal [3], 1.6us periodic signal is computed and applied
Option 3 : A certain sequence based signal in the time domain
By employing a single carrier transmitter, a certain sequence based signal in the time domain is sent
In this contribution, we apply Golay sequence as in 11ad in order to exploit a good autocorrelation property of Golay sequence when performing timing synchronization at the receiver.
Eunsung Park, LG Electronics

6. Simulation Environment
January 2017
Simulation Environment
Each part of the wake-up frame has the following length
Each option for the synchronization has the following structure
Option 1 : two ON-symbols (8us) + one OFF-symbol (4us)
Last OFF-symbol may have a positive effect on the timing synchronization and detection
Also, it can be used to indicate the WUR frame
Option 2 : five 1.6us signals (8us) + one OFF-symbol (4us)
Option 3 : two 64 length Golay sequence based signals (6.4us) + one OFF-symbol (4us)
64 length Golay sequence
[-1,-1,1,-1,1,-1,-1,-1,1,1,-1,1,1,-1,-1,-1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,1,-1,-1,1,1,1,-1,-1,1,-1,1,-1,-1,-1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,-1,1,1,1,1,1,-1,1,1,-1,-1,-1]
OOK symbol is decoded in the frequency domain
Performance may be degraded if the signal decoding is preformed in the time domain since the noise in adjacent tones that cannot be perfectly removed by the filter which is not sharp enough affects the performance
SNR is defined considering 20MHz
PER performance for the wake-up payload will be shown in TGn D channel
Wake-up payload
Wake-up preamble
Control information
(48 symbols)
Detection & Synch
(About 3 symbols)
Signal power measure /
Short control information
(6 symbols, all ON-symbols)
Eunsung Park, LG Electronics

7. January 2017
Simulation Results – Comparison among Options for Timing Synchronization
k = 13
k = 16
Eunsung Park, LG Electronics

8. January 2017
Simulation Results – Comparison among Options for Timing Synchronization
k = 26
k = 32
Eunsung Park, LG Electronics

9. Discussion We assume the target PER of 1% or 10%
January 2017
Discussion
We assume the target PER of 1% or 10%
For the timing synchronization, all options have similar PER performance and the PER performance gap less than 1dB comparing with the perfect synchronization case
However, the transmit complexity is different according to the option
Option 1 is the simplest one since the transmitter only needs to be possible to send the OOK symbol by using the conventional OFDM transmitter
Option 2 needs a procedure which generates a periodic signal as well as the OOK symbol, but the transmitter can use the conventional OFDM transmitter
Option 3 may need the most complex procedure at the transmitter since a single carrier transmission is required
Eunsung Park, LG Electronics

10. Simulation Results – Comparison among Various OOK Pulse Bandwidths
January 2017
Simulation Results – Comparison among Various OOK Pulse Bandwidths
Option 1
Option 2
Eunsung Park, LG Electronics

11. Simulation Results – Comparison among Various OOK Pulse Bandwidths
January 2017
Simulation Results – Comparison among Various OOK Pulse Bandwidths
Option 3
Eunsung Park, LG Electronics

12. January 2017
Discussion
For the OOK pulse bandwidth, there is a trade-off between the PER performance and the power consumption assuming the target PER of 1%
When k=13, it has an advantage of the power consumption but its PER is the worst in all options
When k=16, it achieves a better PER performance than that of k=13 with relatively low power consumption
The cases of k=26 and 32 have a similar PER performance and they overwhelm other cases in all options
Considering the power consumption issue, the case of k=26 may be better than k=32
On the other hand, if we see the target PER of 10%, the case of k=13 may be the best in most cases in terms of both the PER performance and the power consumption
Eunsung Park, LG Electronics

13. Conclusions January 2017 Assuming the target PER of 1%
Month Year
doc.: IEEE yy/xxxxr0
January 2017
Conclusions
Assuming the target PER of 1%
If we focus only on the PER performance, we can choose the following case
8MHz pulse bandwidth (k=26) with option 2 for timing synchronization
However, since the power consumption is a dominant factor in 11ba, 4MHz pulse bandwidth (k=13) can be preferred rather than other cases
If the case of k=16 has an allowable power consumption, then 5MHz pulse bandwidth (k=16) can be selected
On the other hand, in terms of the complexity at the transmitter, option 1 is the most favorable and option 2 is relatively comparable
Thus, considering all of the factors such as the PER performance, the power consumption and the transmit complexity, it may be advisable to apply the following cases to 11ba
4MHz pulse bandwidth (k=13) with option 1 for the timing synchronization
5MHz pulse bandwidth (k=16) with option 1 or option 2 for the timing synchronization
Note that considering the UMi channel as shown in Appendix B, we don’t have any choice but to apply 8MHz pulse bandwidth (k=26) with option 3 for timing synchronization
Only the cases of k=26 and 32 with option 3 achieve 1% PER and other cases can not meet it in the UMi channel
The case of k=32 with option 3 can be excluded considering the power consumption and its worse performance than that of the case of k=26 with option 3
Assuming the target PER of 10%
4MHz pulse bandwidth (k=13) with option 3 for timing synchronization (low power consumption is also achieved)
If we also think about the transmit complexity, it may be advisable to apply the following case to 11ba
4MHz pulse bandwidth (k=13) with option 1 for the timing synchronization (actually, comparable PER with 4MHz w/option 3)
Note that we can have the same conclusions even in the UMi channel as shown in Appendix B
Eunsung Park, LG Electronics
John Doe, Some Company

14. January 2016
References
[1] IEEE /0341r0 - LP-WUR (Low-Power Wake-Up Receiver) Follow-Up [2] IEEE wur-performance-investigation-on-wake-up-receiver [3] IEEE wur-further-investigation-on-wur-performance
Eunsung Park, LG Electronics

15. January 2016
Appendices
Eunsung Park, LG Electronics

16. January 2016
Appendix A
Eunsung Park, LG Electronics

17. Appendix B – PER in the UMI Channel
January 2017
Appendix B – PER in the UMI Channel
Perfect synch.
Option 1
Eunsung Park, LG Electronics

18. Appendix B – PER in the UMI Channel
January 2017
Appendix B – PER in the UMI Channel
Option 2
Option 3
Eunsung Park, LG Electronics