2. Minutes from Feb 28 2007 Conference Call

February 2007 doc.: IEEE 802.22-07/0078r1

IEEE P802.22 Wireless RANs

PHY Minutes from Feb 28, 2007 Conference Call

Date: 2007-02-28

Author(s): Name Company Address Phone email Institute for Infocomm 21 Heng Mui Keng Zander Zhongding Lei 65-6874-5686 [email protected] Research, Singapore Terrace, Singapore 119613

Abstract This document contains the minutes from the PHY conference call on Feb. 28, 2007.

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Submission page 1 Zander Lei / I2R, Singapore February 2007 doc.: IEEE 802.22-07/0078r1

1. Attendance

Feb 1 Feb 8 Feb 15 Feb 22 Feb 28 Changjoo Kim x Myungsun Song x x x Sunghyun Hwang x x x x x Gwangzin Ko x Jungsun Um x x x Soo-Young Chang x x x x x Edward Au x x x x Wai Ho Mow x x x x Zander Zhongding Lei x x x x x Ying-Chang Liang x Chang Long Xu x Ramon Khalona x x x x x Upkar Dhaliwal x x x Monisha Ghosh x x x x x Carlos Cordeiro x Eli Sofer x x x x Steve Kuffner x David Mazzarese x Carl Stevenson x Chris Clanton x x x x Gerald Chouinard x x x x x Einolf x George Vlantis x

2. Minutes from Feb 28 2007 Conference Call

2.1 Agenda

 Updates on modified CAZAC sequences (Wai Ho of Huawei)  Updates on choice of 2 or 3 repetitions of preamble sequence

2.2 Notes

2.2.1 Updates on modified CAZAC sequences Wai Ho (Huawei) presented the updates on Modified CAZAC Sequences (Doc02r4, sent out to reflector a few hours before the call). The updates focused on  Payload PAPR consideration  Receiver complexity issue: Polyphase vs. Binary Preambles  New simulation results for decimation factors 1 and 3 The assumption/proposal in 1st bullet above was “Preamble transmission power is higher than the payload transmission power to provide sufficient preamble SNR”. The feasibility of boosting preamble

Submission page 2 Zander Lei / I2R, Singapore February 2007 doc.: IEEE 802.22-07/0078r1 transmission power in 802.22 was questioned (Monisha, Gerald) due to the 4W EIRP constraint of .22 devices. However, if the 4W EIRP was measured and averaged in a longer period, say in one or more frame periods instead of one symbol period, boosting preamble power should not be a problem. The group felt that if boosting power was allowed according to FCC rule, the CAZAC sequence based preamble proposal would make more sense and get stronger support from the group. Gerald had sent out an email to Carl for clarification on the EIRP measurement issue. The email was also cc to the reflector.

As to the complexity issue of CAZAC sequence, Monisha commented that additional multipliers had to be implemented in the hardware. Wai Ho replied that he had checked with their engineers and the multipliers in other function blocks could be shared. It was not necessary to add in more multipliers in hardware. Regarding computational complexity, it was analyzed as in the presentation slides that, the overall receiver complexity were only up about by <<0.5% as opposed to binary preamble sequence, and only additional shifts and adds, rather than hardware multipliers, are needed. Wai Ho further commented that by choosing the binary preambles, we will not have the flexibility to exploit the potential of the very low PAPR in all future considerations. This potential advantage of CAZAC preambles should be considered especially when the complexity is not really an issue..

Monisha further commented that it was not desirable to have different power levels for preamble and payload when considering AGC setting at the receiver. Due to nonlinearity of AGC circuits, the channel estimated during preamble period would be different from the channel during payload with different AGC setting. The system performance would be degraded.

2.2.2 Updates on choice of 2 or 3 repetitions of preamble sequence Monisha mentioned that there was no further update at her side. She was expecting simulation results from Sunghyun et al (ETRI). She also mentioned that Sectorization had been proposed some time before without using the preamble design proposed by Eli. She asked the group to look at it.

Eli mentioned that there were a lot of simulation results available in 802.16 supporting their preamble design, with benefit of supporting Sectorization.

Monisha argued that there were QoS concerns related to the .16 preamble design.

It was understood that colleagues from Motorola might have more information on .16 preamble design and related issues. Ramon took an action item to contact Steve Kuffner and get back to the group latter.

3. Next Conference Call

The next conference call will be held on Thursday, Mar. 8 at 7 PM PT (10 PM ET). The bridge information is (Thanks to Gerald of CRC)

Telephone number: 888-265-0903 North-America 613.954.9003 International

Access code: 082942

Submission page 3 Zander Lei / I2R, Singapore