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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 RF Feasibility of 120 MHz Channelization for China Date: 2010-09-12 Authors: Slide 1
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Slide 2
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Abstract In this presentation, we analyze the RF feasibility of 120 MHz channelization in China and show it totally meets the 5 GHz RF regulation of China. Slide 3
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Background Compared with legacy 802.11 systems, 802.11ac will support wider bandwidth (up to 160 MHz). Unfortunately, the total available bandwidth in China is only 125 MHz (5,725 ~ 5,850 MHz). –It may cause a serious resource waste, since 125 MHz bandwidth only supports an 80 MHz transmission. –With less channel bandwidth, Chinese users will suffer from higher complexity, worse performance, less device types, and less applications. Slide 4
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Motivation Based on the Chinese requirement, 120 MHz PHY transmission has been proposed for 802.11ac to support Chinese 5GHz spectrum more efficiently. However, there is only 5 MHz bandwidth left for guard bands, which may produce too much out-of-band radiation. In the following, we will analyze the RF feasible of 120 MHz channelization meets the China’s RF regulation or not. Slide 5
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 China’s RF regulation in 5 GHz band The major RF requirements are as follows: –Frequency range: 5,725 ~ 5,850 MHz –Total transmit power: ≤ 27dBm (500mW) –The maximum PSD: ≤ 13dBm/MHz, ≤ 19dBm/MHz (EIRP) –Out-of-band radiation (EIRP): ≤ -80dBm/Hz (-20dBm/MHz) It is noted that the total TX power shall be limited to no more than 17 dBm (50mW), which is 10 dB lower than China’s requirement (27dBm). It means that –there is a 10dB back-off advantage for the PSD of 802.11ac signals, so it is much easier for 120MHz PHY transmission to meet the spectral mask of China. Slide 6
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 China’s 5GHz spectral mask Slide 7 125 MHz The average PSD ≤ 6 dBm/MHz The maximum PSD ≤ 13 dBm/MHz Out-of-band radiation ≤ -20dBm/MHz 5,725 MHz5,850 MHz The average PSD of 11ac ≤ -4 dBm/MHz 16dB 10dB 7dB The maximum PSD (EIRP) ≤ 19 dBm/MHz 6dB
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Simulation parameters For further study, we need a specific 120 MHz channelization scheme. In our simulation, we simply assume it consists of three contiguous 40 MHz 11n channels. According to the EVM document, the toal transmit power is 17dBm (50mW), and the resulting average PSD over 125MHz is -4 dBm/MHz. The power amplifier (PA) model and the phase noise model given in the EVM document are adopted. Different OFDM symbols have different frequency domain characteristics. We consider three kinds of OFDM symbols with different guard intervals. –Normal GI: T GI = T DFT /4 = 0.8 us –Short GI: T GIS = T DFT /8 = 0.4 us –Double GI: T GI2 = T DFT /2 = 1.6 us Slide 8
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 PSD of 120 MHz transmission using normal GI Slide 9
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 PSD of 120 MHz transmission using short GI Slide 10
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 PSD of 120 MHz transmission using double GI Slide 11
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Maximum TX power of 120 MHz transmission The out-of-band radiation of 120MHz transmission is 7.5 ~ 8.5 dB lower than the China’s RF requirement. If necessary, the total TX power (EIRP) can be further increased to improve the coverage by –employing directional antennas, or –simply increasing transmit power If the PA model remains unchanged, then we have Slide 12 Normal GIShort GIDouble GI Max. TX power growth 8.0 dB7.5 dB8.5 dB Max. of average PSD (EIRP) 4 dBm/MHz3.5 dBm/MHz4.5 dBm/MHz Max. TX power (EIRP) 25.0 dBm24.5 dBm25.5 dBm
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Maximum PSD for normal GI Slide 13
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Maximum PSD for short GI Slide 14
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Maximum PSD for double GI Slide 15
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Conclusion It is shown that the PSD of 120MHz channelization completely satisfies the China’s RF regulation in 5GHz band. The out-of-band radiation of 120MHz transmission is 7.5 ~ 8.5 dB lower than the China’s RF regulation, so we can increase the transmit power or employ directional antennas to improve its coverage and performance. Based on its technical feasibility and hugh market demands from China, we propose 802.11ac to support an efficient channelization for China, where the total available channel bandwidth is up to 120 MHz. Slide 16
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 References 11-10-0778-01-00ac-120-mhz-phy-transmission 11-10-0378-01-00ac-160-mhz-phy-transmission IEEE 802.11n standard 11-09-0992-11-00ac-proposed-specification-framework- for-tgac 11-09-0451-14-00ac-tgac-functional-requirements-and- evaluation-methodology Slide 17
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doc.: IEEE 802.11-10/1062r0 Submission Zhendong Luo, CATR September 2010 Strawpoll #1 Do you support adding the following item into Section 3.1 Channelization of the specification framework document, 11-09/0992? R3.1.E: The draft specification shall include support for an efficient channelization in China’s spectrum (5,725 ~ 5,850 MHz), where the total available channel bandwidth is up to 120 MHz. –Yes: –No: –Abstain: Slide 18
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