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Hi Cor, using 11e scheduling and TxOP capabilities may help to solve .11 time reference issue. Also, there are some proprietary solutions for 802.11 based TDMA format, similar to Intel's solution that Richard posted to the group last time; maybe same idea can be used for the control channel, thank you rashid Subject: RE: Straw Poll Survey Results Date: Mon, 17 Aug 2009 19:21:20 +0300 From: marianna.goldhammer@xxxxxxxxxxxx To: CWater@xxxxxxxxxx; sshellha@xxxxxxxxxxxx; stds-802-19@xxxxxxxx; WHITESPACE@xxxxxxxxxxxxxxxxx Hi Cor,
I know that.
But there is a new aspect: for operating in TVWS, it is needed the synchronized silence in order to detect microphones, etc. at -114 dBm. If, for example, this sync silence will not be implemented in 802, the 802.11 TVWS device may detect other 802 devices as TVWS microphone and it will not be possible to re-use the spectrum on 60km!
Once implemented the sync approach (there are many possibilities), the coordination in time becomes possible. As you probably know, the sync over the backbone is already not a problem. Another possibility is that those devices which have external sync (this may be the case of 802.16/22) will transmit the sync info over the air.
Regards,
Mariana
From: Cor van de Water [mailto:CWater@xxxxxxxxxx]
Mariana,
As you probably know, 802.11 does not have a time reference, it is essentially Ethernet over the air, no notion of timeslots or scheduling, just pushing variable length packets in any direction as they come, with a listen-before-talk approach to avoid chaos.
I don't see how you can coordinate that with TDMA systems.
Regards, Director HW & Systems Architecture Group Proxim Wireless Corporation http://www.proxim.com Email: CWater@xxxxxxxxxx Private: http://www.cvandewater.com Skype: cor_van_de_water IM: cor_van_de_water@xxxxxxxxxxx Tel: +1 408 383 7626 magicJack: +1 408 844 3932 Tel: +91 (040)23117400 x203 XoIP: +31877841130 Please consider the environment before printing this e-mail.
From: whitespace@xxxxxxxx [mailto:whitespace@xxxxxxxx] On Behalf Of Mariana Goldhamer Hi Steve,
The time sharing between different technologies (i.e. 802.16/22 and 802.11) may be a-priori scheduled; it will use a common time reference.
It is possible to determine which technology is using the channel based on the occupancy of pre-defined time slots, time-slots which should be assigned separately to each technology.
The basic operation does not require inter-system communication; however, the communication may improve the spectrum usage and the QoS.
I can prepare a presentation for a future teleconf.
Regards,
Mariana
From: Shellhammer, Steve [mailto:sshellha@xxxxxxxxxxxx]
Mariana,
You suggest time sharing and then ask how communicating between devices will help. Well, if you have no communication between devices how to you schedule time sharing? How do you determine who to share with and under what conditions? I don’t know how it can be done without some form of communication. If you can describe how it can be done without any form of communication I think that would be an interesting presentation.
Steve
From: Mariana Goldhamer [mailto:marianna.goldhammer@xxxxxxxxxxxx]
Hi Steve and Rich,
Thanks for clarifications J
I would like to propose that it will be established a methodology for addressing the PAR scope: the proponents of the different approaches should explain how their approach resolves the channel sharing between 802.11 on one side and 802.22/802.16 on the other side, such that an CPE at cell margin will not be interfered by a WLAN.
For example, medium access such to ensure separation in the time domain between 802.11 and 802.16/802.22 clearly resolves the problem. This is different from any existing standard, including P.1900.
To me it is not clear how just communication between systems resolves this problem. Can anybody clarify?
Regards,
Mariana
From: Shellhammer, Steve [mailto:sshellha@xxxxxxxxxxxx]
All,
I agree that it is too early to read too much into these straw polls. We need to understand that these are just that, only straw polls.
They are intended to get a measure on the pulse of the group.
There does seem to be reasonable support for some form of coordination between TVWS devices, for coexistence. What that means in more detail needs to be considered further.
Once we have a little more detail we can always craft a few more straw polls on more specific proposals.
For example, if we assume that communication over the backhaul can be accomplished then we need to put some framework around what type of coordination could be performed.
Steve
From: Rich Kennedy [mailto:rkennedy1000@xxxxxxxxx]
Mariana::
Two comments:
1. These polls were taken without any sort of agreement on the definition of coordination. This lumps together those that believe that a shared goelocation database constitutes coordination, with those that believe an independent control channel is required for coordination. I see nothing decisive in such a poll. 2. With the PAR scope you suggested it will be difficult within the 5 Criteria to show how it is "Substantially different from other IEEE 802 standards", as P1900 is specifically looking at this issue, and both 802.11 and 802.22 have to deal with this issue in their own projects if they have any hope of success with this unlicensed spectrum. And it seems to me that on the call two weeks ago there were still question regarding whether this group will write one PAR or many PARs, and whether those PARs will be directed at a project or projects within 802.19, or for the other groups specifically working on other TVWS PARs, namely 802.22 and 802.11.
This equation still has two many unknowns to try and force a solution out of it.
Rich
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