1. Channelization for China’s Spectrum
January 2010
doc.: IEEE /0084r3
Channelization for China’s Spectrum
Date:
Authors:
Brian Hart, Cisco Systems

2. January 2010
doc.: IEEE /0084r3
Brian Hart, Cisco Systems

3. Abstract
In this presentation, we propose some candidate channelization schemes for China’s 5GHz spectrum.

4. Background
In the last meeting, the following statement was included in the 11ac spec framework.
R3.1.E: The draft specification shall include support for an efficient channelization in China’s (5,725 ~ 5,850 MHz) spectrum.
In [3], it is shown that the total channel bandwidth in China can be up to 120MHz.
In China, the coexistence and compatibility issues are actually not serious, but still need to be considered.
In China, very few devices (esp. APs) work on 5GHz band.
Almost all legacy 5GHz devices can also support 2.4GHz band, and the 2.4 GHz band is the preferred working band.
If the spectrum regulation of China remains unchanged, defining an 120MHz channelization can keep a chance for ac to meet the Chinese requirement.

5. How to do channelization
June 2010
doc.: IEEE /xxxxr0
How to do channelization
Easier networking and better interference avoidance
The number of channels should be as many as possible, e.g., three 40MHz channels, six 20MHz channels.
Higher data throughput
The channel width should be as large as possible.
An option is to define an 120MHz channel in China’s spectrum
Compatibility and coexistence insurance
The channelization should support legacy a/n devices
The channelization should support coexistence with OBSSs working in legacy channels.
Brian Hart, Cisco Systems

6. Proposal 1
Proposal 1 includes two modes (compatibility mode and enhanced mode), in which the 120MHz channel is optional.
7.5MHz
5735
40MHz
80MHz
20MHz
5727.5
5847.5
f MHz
120MHz
5835
12.5MHz
Compatibility mode
Enhanced mode
Compatible with legacy devices
Higer channel utilization efficiency

7. Proposal 2
Proposal 2 consists of the existing 11ac channelization and an optional 120MHz channel.
7.5
5735
40MHz
80MHz
20MHz
5727.5
5847.5
f MHz
120MHz
5835
12.5
Compatible with legacy devices
Higher data throughput

8. June 2010
doc.: IEEE /xxxxr0
Conclusion
Proposal 1 is an efficient and complete channelization scheme, but faces challenges in compatibility and coexistence.
Proposal 2 keeps the existing 20/40/80 MHz channels, has less compatibility and coexistence problems, and is easier to be implemented.
Like 160MHz channel, the 120MHz channel is optional.
The 120MHz channel design is still open, and may be realized by combining the existing 40MHz and 80MHz channels or defining a new waveform.
Some MAC mechanisms have been provided by the co-authers to support our proposals.
Brian Hart, Cisco Systems

9. References 11-10-0778-01-00ac-120-mhz-phy-transmission
ac-rf-feasibility-120-mhz-channelization
ac-proposed-specification-framework-for-tgac

10. Solution 1: BSS alternatively operating on shifted and non-shifted channels in time domain

11. Solution 2: Enable 120 MHz Transmission via PCO
Enable 120 MHz transmission using Phased Coexistence Operation (PCO)
The procedure already exists in 11n to enable alternation of 20 and 40 MHz phases in 11n; a simple extension can be made for 11ac

12. Solution 3: Enable 120MHz data only transmission period (burst-style)
Basically burst-style time division of legacy transaction period and 120MHz data only transmission period
Only data frames and some management frames transmitted with 120MHz bandwidth;
Control frames and most networking joining related management frames transmitted with current channels.

13. Solution 4: Enable 120MHz data only transmission period
Allow phased division of legacy transaction period and 120MHz data only transmission period
AP controlled or STA requested phased division of legacy transaction period and 120MHz data only transmission period
CCA detection on 5 non-shifted 20MHz channels. If all 5 channels are idle, then AP sends CTS-to-self on 5 non-shifted 20MHz channels to reserve 100MHz channel
After120MHz transaction phase starts, AP and 120MHz recipient STAs exchange RTS/CTS on 5 legacy 20MHz channels to avoid OBSS interference
LvKaiying, ZTE Corporation

14. Pre-motion 1
Do you support the following channelization scheme for China, and then modify the 11ac spec framework accordingly?
In this scheme, the 120MHz channel is optional,
5735
40MHz
80MHz
20MHz
5727.5
5847.5
f MHz
120MHz
5835
Compatibility mode
Enhanced mode

15. Pre-motion 2
Do you support the following channelization scheme for China, and modify the 11ac specification framework document accordingly?
In this scheme, the 120MHz channel is optional.
5735
40MHz
80MHz
20MHz
5727.5
5847.5
f MHz
120MHz
5835