1. 11ah Channelization Discussion
September 2006
doc.: IEEE /1458r0
September 2011
11ah Channelization Discussion
Date:
Authors:
James Wang et al
Joonsuk Kim, Broadcom Corp.

2. FCC Part 15 (US) Frequency Hopping Scheme should be avoided.
2019/12/18
FCC Part 15 (US)
Frequency Hopping Scheme should be avoided.
Adrian Stephen Jan 04, 11 opposed the use of Frequency Hopping.
§ a.(2) Systems using digital modulation techniques may operate in the 902–928 MHz, 2400– MHz, and 5725–5850 MHz bands. The minimum 6 dB bandwidth shall be at least 500 kHz.
To avoid using FH, channel bandwidth in US needs to be > 500 kHz
James Wang et al

3. Example Timing Related Parameters: Downclocking of 11ac by 10
September 2011
Example Timing Related Parameters: Downclocking of 11ac by 10
Corresponding 11ac BW
MHz 20 40 80
160
FFT Size 64
128
256
512
Tfft: Inverse FFT Period
μS (1/Δf)
3.2
TGI: Guard Time μS .4 BW 1 2 4 8 16 32
Sampling Frequency
Cyclic Prifix, Sample
Sample
TGI: Guard Time Duration μs
Number of Data Subcarriers 26 52
108
234
468
Number of Pilot Subcarrier 6
Δf: Subcarrier Spacing
kHz
31.25
Tsymbol: Symbol Duration
Note: Sub 1MHz BW TBD,
James Wang et al (MediaTek)

4. Regulatory Restrictions on Channel/BW
September 2011
Regulatory Restrictions on Channel/BW US
Japan
China
Singapore
Korea
Europe
Channel
100kHz
/200kHz
200kHz/400kHz /1MHz?
200kHz
Min BW
500kHz
Max BW
None
1MHz
1MHz ( , MHz)
.6/3/7 MHz
Ref Doc # ,
Note from ZTE presentation:
200KHz limitation in Band 470MHz-510MHz leads to limited date rate, may satisfy use case 1 categories, but hard to support use case 3 with up to 10Mbps
400KHz limitation in Band 314MHz~316MHz and 430MHz~434MHz doubles previous 200KHz, and provided limited date rate too
No limitation in 779MHz~787MHz
James Wang et al (MediaTek)

5. Channelization/Bandwidth Proposal
2019/12/18
Channelization/Bandwidth Proposal
Channelization/Bandwidth affects the choice of the reference clock for PLL (needs to step through channel)
Too high a reference clock results in difficulty in the band edge alignment (waste of bandwidth)
Too small a reference clock affects phase noise and synthesizer choice (fractional vs integer)
Proposed BW: 1/2/4/8/16 MHz (Narrower BW TBD)
Note: Another possibility is .625M/1.25M/2.5M/5M/10M/20M
Too wide for Japan, China
James Wang et al

6. September 2011
Straw poll
Do you support the bandwidths of 1, 2, 4, 8, 16 MHz with narrower bandwidth TBD for 11ah?
Yes No
Abstain
James Wang et al (MediaTek)

7. Example Timing Related Parameters: Shorter Guard Time
September 2011
Example Timing Related Parameters: Shorter Guard Time
Corresponding 11ac BW
MHz 20 40 80
160
FFT Size 64
128
256
512
Tfft: Inverse FFT Period
μS (1/Δf)
3.2
TGI: Guard Time μS .8 BW 1 2 4 8 16 32
Sampling Frequency
Cyclic Prifix, Sample
Sample
TGI: Guard Time Duration μs
Number of Data Subcarriers 26 52
108
234
468
Number of Pilot Subcarrier 6
Δf: Subcarrier Spacing
kHz
31.25
Tsymbol: Symbol Duration 36
Note: Sub 1MHz BW TBD
James Wang et al (MediaTek)