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March 2009Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [Smart Grid Communications Preliminary Proposal]Date Submitted: [March 1, 2009]Source: [Robert Mason] Company [Elster Electricity]

[Jeff McCullough] Company [Elster Electricity][David Hart] Company [Elster Electricity]

Address: [208 South Rogers Lane; Raleigh, NC 27610] Voice:[919-250-5819]

E-Mail: [david.g.hart@us.elster.com]

Re: [TG4-SUN PHY Layer Proposal]

Abstract: Preliminary Proposal for Smart Utility Networks aka Smart Grid Communications

Purpose: Contribution to Smart Grid Communications

Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

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Proposal to TG4-SUN

Smart Grid Communications

March 1, 2009

IEEE 802.15.4

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March 2009

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The Smart Grid vision…

• Secure standards based communications help to improve electric system operation

• Enables alternate forms of energy generation and usage

• Proactively alerts utility of problems on the grid

• Empowers consumers with information

• Supports Green initiatives

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March 2009

• Provide usage information to consumers• Provide information from and control of the power grid• Bi-directional and net metering for new power sources• Electric consumption data on hourly or sub-hourly basis• Water consumption • Gas consumption• Support business logistics

On-request reads Operational control Outage and restoration management

• Support for future applications

Smart Grid Needs

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March 2009

• Endpoints at all points of service or in premise Not mobile – limited installation options

• Requires robust communications over long distances • Battery powered water and gas devices

Up to 20 years life• Support broadcast messages for utility applications such as

load control• Support on request reads in seconds• Support control in seconds• Secure to prevent others from un-authorized access or

denial of service

Network Considerations

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March 2009

SUN – Smart Grid Examples

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March 2009

Real World Deployment

• Technology based on 900 MHz FHSS has been field proven • Over 2 million Elster smart grid points are deployed

• Smart Grid• IHD• PCT • Electric• Water • Gas

• 50+ Systems deployed 7 different countries• 5 Years experience with true 2-way utility smart grid communications

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March 2009

• Define an alternate PHY layer for 802.15.4 with only those MAC modifications needed to support the PHY layer implementation

• Support operation in any of the regionally available license exempt frequency bands, such as 700MHz to 1GHz, and the 2.4 GHz band

• Data rate of at least 40 kbps but not more than 1000 kbps• Achieve the optimal energy efficient link margin given the environmental

conditions encountered in Smart Metering deployments• Principally outdoor communications • PHY frame sizes up to a minimum of 1500 octets • Simultaneous operation for at least 3 co-located orthogonal networks• Connectivity to at least one thousand direct neighbors characteristic of dense

urban deployments• Provide mechanisms that enable coexistence with other systems in the same

band(s) including IEEE 802.11, 802.15 and 802.16 systems

Scope/Goals of TG4g-SUN

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March 2009

Define an alternate PHY layer for 802.15.4 with only those MAC modifications needed to support the PHY layer implementation

Overview of Proposed PHY Layer• 902-928 MHz ISM band• FSK modulation• 400 kHz channel spacing to support higher data rates• Two bands in 902-928 MHz region. Each band uses 25 channel FHSS• Programmable output power (to suit various device types)• Data rates between 9.6 and 300 kbps

Proposal to Address Goals of TG4-SUN

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March 2009

Support operation in any of the regionally available license exempt frequency bands, such as 700MHz to 1GHz, and the 2.4 GHz band

Comparison of frequency bands• Unlicensed options below 902 MHz are very limited and offer narrow bandwidth• 2.4 GHz band is very congested and doesn’t offer the robust PHY layer required

to meet the requirements of Smart Utility Networks (SUN)• 902-928 MHz band offers both bandwidth and robustness required to meet the

requirements• Proposal is not restricted to the 902 – 928 MHz band, but satisfies the goals

within one band

Proposal to Address Goals of TG4-SUN

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March 2009

Support operation in any of the regionally available license exempt frequency bands, such as 700MHz to 1GHz, and the 2.4 GHz band

Comparison of 900 MHz and 2.4 GHz unlicensed bands 900 MHz signals propagate farther than 2.4 GHz

Free space loss is approx. 10 dB higher for 2.4 GHz as compared to 900 MHz Distance of 900 MHz is typically 2.5 times better than 2.4 GHz

900 MHz signals penetrate better than 2.4 GHz Ability to overcome obstacles (buildings, trees) Buildings, and other obstacles attenuate 2.4 GHz more than 900 MHz

900 MHz signals are absorbed less than 2.4 GHz Multi-path fading (reflection) is worse at higher frequencies Walls, pine needles, other materials absorb (attenuate) 2.4 GHz more than 900 MHz Weather (fog, rain) attenuate 2.4 GHz more than 900 MHz

Proposal to Address Goals of TG4-SUN

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March 2009

Data rate of at least 40 kbps but not more than 1000 kbps

Proposed PHY Layer• Supports variable data rates between 9.6 and 300 kbps• Data rate allowed to vary based on device type

Provides a low data rate for simple low end devices, while also providing a higher data rates for large data/message transport

Proposal to Address Goals of TG4-SUN

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March 2009

Achieve the optimal energy efficient link margin given the environmental conditions encountered in Smart Metering deployments

• Proven operation in Smart Metering deployments• Proven in outdoor environments• Proven with all types of smart meters (electric, gas, water, etc)• Proven reliable communications to bridge utility to in-home devices

Supports communications from meter into the home Both single family residential and multi-unit structures (e.g. apartment

complexes)• Frequency band selection is critical. 900 MHz band is proven

Proposal to Address Goals of TG4-SUN

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March 2009

Principally outdoor communications

• Communication backbone is principally outdoors, BUT it is critical to get from the meter into the home

Must get from electric meter into the home Must support multi-home dwellings

• Propagation distances and penetration of 900 MHz signals provides range and robustness for outdoor communications AND communications INTO the residence

Proposal to Address Goals of TG4-SUN

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March 2009

Proposal to Address Goals of TG4-SUN

PHY frame sizes up to a minimum of 1500 octets

• Simple PHY frame structure• Variable frame size• Support for very large payloads• Data whitening performed as software algorithm – no PHY space

required for whitening

Field: Preamble SFD Length PHY Payload CRC

Octets: variable 2 2 variable 2

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March 2009

Simultaneous operation for at least 3 co-located orthogonal networks

• With frequency hopping systems, FCC requirements specify minimum bandwidth requirements

• Three networks in the 902-928 frequency band would enforce a bandwidth limitation that is not desired

• Proposed system supports two networks in the 902-928 MHz band• Both networks can fully co-exist• Devices can participate in only one or both networks

Proposal to Address Goals of TG4-SUN

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March 2009

Proposal to Address Goals of TG4-SUN

Simultaneous operation for at least 2 co-located orthogonal networks

• At least 2 networks in a given frequency band.• Example, 902-928 MHz band:

400 kHz channel spacing. 32 channels for each network Split frequency allocation provides flexibility for international locations

where 902-915 MHz region is not available for use, but 915-928 MHz region is available.

Allows a single device to operate on two networks with minimal hardware

Network #1 Network #2902 - 915 MHz 915 - 928 MHz

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March 2009

Connectivity to at least one thousand direct neighbors characteristic of dense urban deployments

• Networks deployed and demonstrating more than one thousand direct neighbors

• Network structure is primarily based on a network coordinator to multiple devices, but also supports peer to peer communications

• Millions of devices deployed around the world

Proposal to Address Goals of TG4-SUN

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March 2009

Provide mechanisms that enable coexistence with other systems in the same band(s) including IEEE 801.11, 802.15, and 802.16

• FHSS communications provides best option for coexistence Fixed channel selection (as per DSSS) is not required

• 900 MHz band is less crowded and avoids many other systems (801.11, 802.15, 802.16) that are predominately in other bands

• Proven network performance in the presence of commonly encountered interference sources

Proposal to Address Goals of TG4-SUN

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March 2009

Additional Features

• Stand-alone infrastructure is not required – all powered devices route messages within network

• Simplified network access and synchronization to support device types found in utility networks (electric, gas, and water)

• QoS management Communication paths are qualified by multiple metrics Deterministic, controlled routing

• Mesh network Supports both client and master initiated messages Supports unicast and broadcast messaging Supports peer to peer messaging

• Proven performance in both dense and sparse deployments

Proposal to Address Goals of TG4-SUN

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March 2009

Recommendation for addition to scope/goals of TG4-SUN

• Must support all types of utility networks Electric Gas Water

• Must support low power (i.e. battery powered) devices

Proposal for TG4-SUN

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Thank you!!