May 2007 doc.: IEEE 802.22-07/0225r0
IEEE P802.22
Wireless RANs
Held May 3, 2007 at 9am EST
Date: 2007-05-03
Author(s):
Name / Company / Address / Phone / email
Zander Zhongding Lei / Institute for Infocomm Research, Singapore / 21 Heng Mui Keng Terrace, Singapore 119613 / 65-6874-5686 / leizd@i2r.a-star..edu.sg
1. Attendance
Mar 29 / Apr 5 / Apr 12 / Apr 19 / Apr 26 / May 3Myung-Sun Song / x
Sunghyun Hwang / x / x / x / x / x
Jungsun Um / x / x / x / x
Soo-Young Chang / x / x / x / x / x / x
Edward Au / x
Zander Zhongding Lei / x / x / x / x / x / x
Changlong Xu / x / x
Monisha Ghosh / x / x / x / x
Carlos Cordeiro / x
Gerald Chouinard / x / x / x / x / x / x
Carl Stevenson / x / x / x
Cheng Shan / x / x / x / x / x / x
Eli Sofer / x / x
Vadim Neder / x / x
Ramon Khalona / x / x / x / x
John Benko / x
Ivan Reede / x
2. Minutes from May 3 2007 Conference Call
2.1 Agenda
· Updates on VoIP block size, Ranging, AMC etc. (Gerald, Ramon, Sung Hyun, Jung Sun)
· Addressing referred comments 224, 93, 522 by MAC on superframe preamble.
2.2 Notes
The meeting was called to order at 9 am ET.
VoIP Block Size
Gerald reviewed the newly updated document 190r2 “OFDMA block sizes”. It listed possible block sizes for a rectangular downstream (two options included: 30 subchannels and 60 subchannels) capacity allocation. For upstream (60 subchannels), both 'linear' and rectangular allocation are considered. The block sizes used by FEC Team for simulations were highlighted.
Regarding the number of subchannels, Gerald commented that it would be nice to have the same number (60) of subchannels for upstream and downstream. It would be easier for AMC operation as well. (If downstream employs 30 subchannels, one downstream subchannel will have twice the number of subcarriers as one upstream subchannel)
Hyun Sung commented that the most important factor is granularity. Although he prefers 30 subchannels option for downstream, he would not insisted on it if there was a good reason for that. He mentioned that there was also another factor, i.e., feedback overhead for AMC. The less number of subchannels, the less feedback bits (overhead) required. He was going to quantify the overhead and send out the analysis to the reflector later.
Ranging
Jung Sun of ETRI summarized the discussion status with Ivan on ranging text. There were two types of ranging in the current draft. One was initial ranging with help of Management message to synchronize to the system for the first time. The other is periodic ranging using CDMA codes. It seemed it would be easier to combine with Ivan’s proposal for the first type and more difficult for the second. Jung Sun and Ivan would have a face to face meeting right before the working group May meeting.
Ivan commented that they proposed using single step ranging, instead of Jung Sun mentioned two-step ranging (fine ranging after initial ranging). In his opinion, there seemed no point to have two-step ranging. So far, he did not see any problem of merging the two proposals from Ivan and Jung Sun. He mentioned that their proposed method was based on the knowledge and estimation of pilot tones. Other than that information, they would be very flexible. They did not care whether the pilot tones would be spread by CDMA codes.
Adaptive modulation
The discussion focused on whether we needed to have another ‘mixed band’ subchannels, apart from diversity and AMC subchannels. Gerald suggested Jung Sun providing the performance improvement figure (# of dB gain) so that the group would have a better idea to make decision in the May meeting. It would be much cleaner and less complex to have only two types of subchannels if the improvement of having ‘mixed band’ is insignificant. Jung Sun would conduct simulations on that and send out the results, together with complexity analysis before May meeting.
Gray mapping
A different Gray mapping from what in the draft (proposed by Ramon) had been suggested by Hyun sung. Hyun Sung submitted further information for Ramon review. Since Ramon was not on the call unfortunately, the discussion was postponed and could proceed by email.
Design new superframe preamble as referred by MAC team
The issue was brought up by Baowei Ji of Samsung during MAC team conf. call. It was decided by MAC team to refer to PHY team to propose new superframe preambles. Since Baowei was not available on PHY conference call before May meeting, the group decided to postpone the discussion till May meeting for more information, e.g, requirement for the preamble design etc.
2.3 Next call
The group decided to skip the next call to let the group have more time to review V0.3 working document to be posted on line soon, considering there was no big issue left on the table.
Submission page 1 Zander Lei, I2R