Download - IEEE Mentor

doc.: IEEE 802.11-10/1210r1
October 2010
Smart Grid Technology Discussions 2010
Name
Company
Address
Phone
email
Bruce Kraemer
Marvell
5488 Marvell Lane,
Santa Clara, CA, 95054
+1-321-751-3988
[email protected]
Jorjeta Jetcheva
Itron
Date: 2010-October-18
Abstract:
NIST PAP#2 Report r6 recommended changes
Submission
Slide 1
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
NIST PAP#2 Report Comments
that complement text in Section 6 & 7 of r6
Submission
Slide 2
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #01
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Section 4.2.1.3 talks about Coverage Area. It is important to
discuss coverage in conjunction with data rates and link margin
for example, in order to avoid associations between inconsistent
pieces of information, e.g., citing the largest coverage area
achievable by a given technology along with the highest data rate
achievable by the technology is incorrect – generally the two have
a reverse relationship and the highest coverage is achievable at
the lowest data rate.
Agreed to text change:
Add the following text at the end of Section 4.2.1.3: When
comparing coverage areas between different technologies, it is
important to take into account the link budgets used in the
coverage computation. Note that the largest coverage area
achievable by a specific technology typically requires
transmission at the lowest data rate used by that technology.
Submission
Slide 3
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #02a
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Section 4.2.1.4 talks about Mobility. It would be useful to
mention the data rates achievable at various mobility levels to
avoid assumptions that mobile devices can communicate at the
highest data rates used by a specific technology.
Agreed to text change:
Add the following text at the end of Section 4.2.1.4: Comparisons
between the capabilities of different mobile technologies have to
take into account the maximum data rate achievable at each
mobility level -- mobile devices may not be able to communicate
at the highest available data rates when moving at high speeds.
Submission
Slide 4
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #03
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Section 4.2.1.5 talks about Data Rates.
Agreed text change:
Add the following text at the end of Section 4.2.1.5: Additional factors to
consider when discussing data rates:
Throughput must be considered in conjunction with packet size,
coverage range and rate of mobility (if any).
It is important to distinguish between unicast, multicast and broadcast
rates, as they may not be the same for a given wireless technology.
Throughput depends on medium access scheduling, including the
capability to provide block transmissions (whereby multiple data packets
can be sent in succession with minimum or no individual medium access
operations per packet except before the first packet is sent), and/or block
acknowledgements (whereby a single acknowledgement packet can
acknowledge multiple preceding data packets). The capability and
flexibility to optimize block transmissions and acknowledgements can
have a significant effect on GoodPut.
The use of rate adaptation mechanisms, where the data rate on a link is
modified when the quality of the link changes.
Submission
Slide 5
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Add these definitions to Section 2.2
Broadcast
• Broadcast is a form of message transmission where a message
is sent from a single source to all potential receiving nodes.
Multicast
• Multicast is a form of message transmission where a message
is sent from a single source to a subset of all potential
receiving nodes. (The mechanism for selecting the members of
the subset is not part of this definition.)
Unicast
• Unicast is a form of message transmission where a message is
sent from a single source is sent to a single receiving node.
Submission
Slide 6
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #04
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Section 4.2.1.6 talks about RF utilization.
Agreed text change:
Add the following text at the end of Section 4.2.1.6:
– Consider the power level regulations for the different channels
used by a particular technology.
– Consider the impact of Dynamic Frequency Selection (DFS)
regulations on the channels used by a particular technology, e.g.,
certain UNII channels are subject to DFS regulation which
requires wireless devices to change channel when they detect the
use of radar on their current channel.
Submission
Slide 7
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #05
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Section 4.2.1.7 talks about Data Frames and Packets. It is important to
consider frame duration in conjunction with data rate and size of the
frame. Also, we need to consider multicast and broadcast frames in
addition to unicast frames.
Agreed text change:
Modify item “a)” in Section 4.2.1.7 as follows:
What is the maximum frame duration for a unicast, multicast and
broadcast frame respectively, and what are the corresponding frame size
and data rate at which each type of frame was sent?
Modify item “b)” in Section 4.2.1.7 as follows:
What is the maximum packet size that can be sent in one unicast,
multicast and broadcast radio frame respectively?
Modify item “c)” in Section 4.2.1.7 as follows:
Does the radio system support segmentation of unicast, multicast and
broadcast packets respectively, when the payload size exceeds the
capacity of one radio frame?
Submission
Slide 8
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #06
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Section 4.2.2.4 talks about Connection Topologies. The Bus and Ring
topology need to be removed, they are not wireless topologies. One way
to characterize wireless topologies is as single hop and multi-hop
(statically configured or mesh), and wireless links as point-to-point,
point-to-multipoint, and omnidirectional. We need to add figures that
correspond to the text we end up with.
Agreed text change:
Remove the Bus and Ring figures
Replace the current text in Section 4.2.2.4 with the following: Wireless
network topologies can be divided into single hop and multi-hop, where a
multi-hop topology can be statically configured, or can be dynamic and
self-forming, e.g., a mesh. A wireless link can be point-to-point, point-tomultipoint, or broadcast.
Add the definitions on the following 4 slides to Section 2.2
Submission
Slide 9
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Hop Definitions
• Proposed PAP2 Guidelines Document Definitions
• Hop: The term hop is used to signify a link between a
pair of devices that a frame or packet needs to traverse
to reach one device from the other.
• Single-Hop Network: A single-hop network is one in
which devices can only communicate with each other
directly, e.g., over a single link (hop), and do not have
the capability to forward traffic on each other’s behalf.
• Multi-Hop Network: A multi-hop network is one in
which devices have the capability to forward traffic on
each other’s behalf and can thus communicate along
paths composed of multiple links (hops).
Submission
Slide 10
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Configuring Definition
• Statically Configured Multi-Hop Network: A multi-hop
network can be statically configured, such that each node’s
forwarding decisions are dictated by configuration.
• Dynamic and Self-Configuring Multi-Hop Network: A
multi-hop network can be dynamic and self-configuring,
such that network devices have the ability to discover
(multi-hop) forwarding paths in the network and make
their own forwarding decisions based on various preconfigured constraints and requirements, e.g., lowest delay
or highest throughput.
Submission
Slide 11
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
MESH Definition
• Mesh Network: A mesh network is a dynamic selfconfiguring network composed of devices that can forward
traffic on each other’s behalf, have the ability to discover
(multi-hop) forwarding paths in the network and make
their own forwarding decisions based on various preconfigured constraints and requirements, e.g., lowest delay
or highest throughput.
Submission
Slide 12
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #07
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Section 4.2.2.5 talks about Connection Management. The
section needs to mention what aspects of “connection
management” can be used to compare different wireless
technologies. For example, we can evaluate the latency to
join a network, available security mechanisms employed
when joining a network, and overhead to join the network
(number of control packets exchanged). Perhaps section
titles such as “Network Participation Mechanisms” or
“Joining the Network” are more descriptive of the content
of this section.
Submission
Slide 13
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment 07b
Add the following text at the end of Section 4.2.2.5:
• It is important to evaluate:
– the time it takes for a device to join a particular network, and the
overhead required to do so
– the time and overhead required to rejoin the network when a device
becomes disconnected from the network
– the overhead required to maintain membership in the network after the
initial admission into the network
– the overhead associated with optimizing connectivity, e.g., in mesh-based
topologies.
Submission
Slide 14
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #08
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Section 4.2.3.2 talks about Location Characterization. It seems like
many of the techniques applicable to this section are not technologyspecific but implementation-specific and as such can be incorporated
across different wireless technologies even if they are not currently
incorporated into the products of a specific wireless technology. It
would be helpful to make the distinction between technology-specific
properties and product-specific properties in the text.
Agreed text change:
Add the following text at the end of Section 4.2.3.2:
It is important to distinguish between technology-specific
mechanisms for location characterization and mechanisms
that are applicable across technologies or communication
topologies, which can easily be added to products that may
not currently support them.
Submission
Slide 15
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #09
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A category that is missing from Section 4 is one that characterizes
the deployment complexity of each technology.
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Agreed text change: Add the following text after Section 4.2.4.1:
4.2.5 Group 22: Deployment Complexity
It is important to evaluate the complexity of:
– installation and maintenance of a given wireless system
– integration with other, possibly existing, networks
– expansion of the wireless network coverage over time.
Submission
Slide 16
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
General Comment #10
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It would be helpful to have some tables and text
summarizing the information in Section 5, and to move a
lot of the discussions/derivations to an appendix.
Otherwise, the message/conclusions/recommendations
get lost in the text.
Submission
Slide 17
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
General Comment #11
Section 4.2.1.2 (p. 24) talks about voice and video traffic over the smart
grid.
We need more use cases motivating why we would want to have voice and
video traffic over the smart grid network. The current set of use cases
supplied by OpenSG does not currently contain this service.
The only video example given in the text is one of surveillance of affected
outage areas. It would seem that voice and video might be of lower
priority during outages, e.g., caused by disasters or weather-related
events, since the network would require a high degree of availability
for its regular functions. In addition, surveillance is generally part of
the public safety infrastructure and there is spectrum allocated for
such use so I am not convinced that we should be discussing this kind
of application in the context of the smart grid.
• Applications such as voice and video have requirements that even
broadband network providers are struggling with (wireless and
landline) and making them part of the smart grid infrastructure
requires significant justification.
Submission
Slide 18
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
General Comment #12
• Link Availability in Section 4.2.1.1 does not appear to be
consistently calculated for the various candidate various radio
technologies, nor did majority of the technology candidates
describe the method used to calculate availability.
• The current description of the characteristic does not match
the calculation.
• Both of these issues need to be resolved before progressing to
completion of Sections 6 & 7.
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“The technology “Operating Point” chosen is presumably chosen recognizing that
achieving a low failure rate is desirable.”
• Agreed text change: Change this sentence to
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“The technology “Operating Point” is chosen to achieve a low failure rate and is an
outcome of deployment flexibility & strategy.”
Submission
Slide 19
Bruce Kraemer, Marvell
doc.: IEEE 802.11-10/1210r1
October 2010
Comment #13
Para 2 Recommended change
• Reword the preface to incorporate the idea that SG application
requirements evolve over time, yielding to experience rather than
remain locked in 1989 or 1999 or 2009 economics.
• Smart Grid application requirements must be defined with enough
specificity to quantitatively define communications traffic and levels of
performance over the lifetime of the applications. Applications
requirements must be combined with as complete a set of management
and security requirements for the life-cycle of the equipment. The
decisions to apply wireless for any given set of applications can then be
based on expected performance and costs over the projected useful
lifetimes of the spectrum and equipment.
Submission
Slide 20
Bruce Kraemer, Marvell