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Hi Mariana, Yes, 802.19 does not design the protocols, but
understanding how system work should be factored into how we measure
coexistence going forward. As I said below: At a minimum, if a throughput metric is
used instead, there must be a solid requirement that system A’s impact on
the throughput of system B must be simulated for a variety of cases where
system A has low or no demand. It’s not clear to me why such an
obvious part of coexistence shouldn’t be measured. Regards, Ken From: Mariana
Goldhamer [mailto:marianna.goldhammer@xxxxxxxxxxxx] Hi Ken, I think that we do not discuss in this group
how the 16h protocols are designed. The only issue which is relevant for 802.19
is the coexistence assessment. So you can keep your design based on any
criteria you want. The metrics, as throughput, relative throughput and hidden
nodes will show how your solution behaves. The same about CX-CBP. The
parameter document has enough modes to address the situations of concern to
you. It is better to use the time and see
the simulation results and to try to understand them and interpret them,
instead of conducting discussions on what the “medium occupancy”
should be. The aggregate throughput (or relative throughput) of the two systems
is an excellent metrics for seeing how flexible their coexistence is. You can
try different loading levels. The hidden nodes are an excellent metrics
to show how many of the stations will suffer from “harmful”
interference. Regarding the technology itself, it will be
chosen by operators based on economic arguments. The coexistence can be first
addressed by operator coordination and the protocols will further help. We are
all aware that there is no perfect solution. 11y has defined a better energy
detection level, however it is far from being perfect because the system shall
first work and be economically viable. FCC did not defined what
“coexistence” means and actually what we are looking for are just
“mitigation” techniques. Regards, Mariana J From: Kenneth Stanwood
[mailto:KStanwood@xxxxxxxxxxxx] It’s not clear my reply made it to
everyone the first time. Ken From: Kenneth Stanwood
[mailto:KStanwood@xxxxxxxxxxxx] I am still very concerned about the insistence
to remove the channel occupancy metric without an appropriate replacement.
As was discussed in In particular, it is important to see how a
technology blocks access by others when the first technology has little or no
actual data to send. As we are already aware, any 802.16/WiMAX based technology
should be suspect due to the designed operation of unmodified WiMAX systems.
Modified WiMAX systems should be required to prove they do not limit
access by other technologies under low demand situations within the WiMAX
system. NextWave proposed the channel occupancy metric in question
because inclusion of that metric in our simulations was key to understanding
and modifying the WirelessMAN-UCP protocol in section 6.4 of 802.16h so that it
would not excessively block access by similar channel bandwidth 802.11 systems
when the 802.16 system had low demand. It is not clear to me that the
WirelessMAN-CBP protocol described in section 15 of 802.16h has addressed this
problem. Lack of an appropriate metric could hinder the identification
and resolution of issues in currently proposed systems and systems likely to be
proposed in the future. I understand the reluctance to accept the
metric. At NextWave we had heated internal debate over whether or not to
include the metric in our simulations, but when the results came in and the
value was overwhelmingly apparent argument ceased. At a minimum, if a throughput metric is
used instead, there must be a solid requirement that system A’s impact on
the throughput of system B must be simulated for a variety of cases where
system A has low or no demand. Thanks, Ken From: Mariana
Goldhamer [mailto:marianna.goldhammer@xxxxxxxxxxxx] Hi All, Regarding the yesterday teleconf and the
way forward: 1. In my view metrics which do not have a
clear interpretation as coexistence criteria shall be omitted, and this is the
case of the Medium occupancy where two opposite target criteria were proposed
by Paul and Eldad (Paul – 50% of time in case of two collocated systems
– was no agreement on this, because is ignoring the antenna separation,
powers, modulation, coding, etc.; Eldad 100% or similar occupancy). In addition
it is not defined yet what the occupancy is, and we spent 45min. just with a
discussion on the different possibilities. This in addition to the time spent
in the meeting. 2. I (and probably many others) appreciate
the straightforward metrics and criteria proposed by Richard, looking at the
relative throughput degradation of the two systems as result of interference.
Similar degradation means acceptable coexistence. 3. The hidden nodes are also important,
being the exact image of the “harmful interference”. The reception
of the signal is directly affected by the hidden nodes. The hidden node
statistics is “hidden” in the averaged throughput results, and this
is why we need this metrics in addition to the throughput. 4. I think that for the next teconf. we
need to invest the time in advancing the CA document itself. We need to discuss
the simulation results and agree on the CA text. 5. We spent already more than one year on
this issue (Apr. 07 is the date of the first parameter document), in meetings
and bi-weekly teleconf. I hope that we will be able to finalize this process
asap. We have committed for a much shorter process and the planned resources
have gone. Probably the 802.19 guys have also other issues to address. Regards, Mariana From: Shellhammer,
Steve [mailto:sshellha@xxxxxxxxxxxx] Minutes posted on the server, https://mentor.ieee.org/802.19/file/08/19-08-0002-11-0000-conference-call-minutes.doc Steve ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(190). ************************************************************************************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(42). ************************************************************************************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(43). ************************************************************************************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(190). ************************************************************************************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(42). ************************************************************************************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(43). ************************************************************************************ |