Review on the Proposed Survey of Wireless Sensor Requirements

1. Review on the Proposed Survey of Wireless Sensor Requirements Presented by David Perrussel Naval Surface Warfare Center – Dahlgren Division Dahlgren, VA May 20, 2002

2. Don’t Get Stuck In Requirements

3. Goal: A Wireless IEEE 1451 Sensor • The IEEE 1451 family of standards is intended to provide a set of low-level standards that manufacturers can use to build their transducers that can be interoperable with different networks. • The new study group is addressing a wireless member of the family that would make the connection between the transducer modules and the NCAP over an RF link

4. Goals for P1451.5 SG • A standard or group of standards for wireless sensor systems • Use IEEE 1451 as a basis • Make use of 1451’s TEDS (transducer electronic data sheet) • Explore various wireless media concepts • Interoperability

5. DefiningRequirements • Requirements need to be defined before standard can be made • Must fit users needs • Must allow for interoperability

6. Don’t Get Stuck In Requirements

7. Ask For User Needs • What are the user needs? • Conduct a survey of users and developers • Combine results to help make standard

8. User Needs Survey • Data/Bit rates per network access node • Rate for periodically transmitted messages • Burst traffic • Application • Range • Number of units in a given area (network) • Latency

9. User Needs Survey • Expected Battery Life • Desired Battery Capacity • Intrinsic Safety • Antenna size – Internal or External

10. User Needs Survey • Security • Data Integrity • Data Freshness • Confidentiality • Authentication • Key Distribution

11. Enter the number of messages you expect at each rate and number of payload bits Message Rate (messages per second) < 0.01 .01 to .1 .1 to 1 1 to 10 10 to 100 100 to 1000 >1000 1 8 12 16 24 32 Table 1 - Rate table for periodically transmitted messages Payload Bits Per Message

12. Bits per message Typical messages per hour Table 2 – Burst Traffic

13. Application • Please provide a very brief description of the application. • This information will be used to get an idea of how the applications break down.

14. Range • The study group needs an idea of the typical distance between a transmitter and a receiver.

15. Range description Range Very Short < 10 meters Short 10 – 100 meters Medium 100 – 1000 meters Long >1000 meters Table 3 – Range Definitions

16. Number of Units In An Area (Network) • Please provide an estimate of the number of remote units connected to a single network access point.

17. Latency • The time between when a sample is requested or scheduled to be taken from a sensor or supplied to an actuator and when the data becomes available to/from the network. This should include delays in the NCAP.

18. Batteries • Expected battery life - The number of months or years you would expect the battery to supply energy in your application. If batteries are not needed, please enter N/A. • Desired battery capacity – Capacity of batteries in miliamp-hours • Desired Battery Size - Provide the maximum battery size that you would accept

19. Intrinsic Safety • Is intrinsic safety a requirement?

20. Antenna Requirements • Internal or External?

21. Security • Data Integrity • Data Freshness • Confidentiality • Authentication • Key Distribution

22. Data Integrity • Does not require detection of accidentally corrupted or maliciously altered messages. • Requires detection of only accidentally altered messages (CRC). • Requires detection of either accidentally altered or maliciously corrupted messages (HMAC).

23. Data Freshness • Does not require detection and/or discarding of old/stale, unordered, or duplicated messages. • Requires detection and/or discarding of old/stale messages. • Requires detection and/or discarding of unordered messages. • Requires detection and/or correction of unordered messages. • Requires detection and/or discarding of duplicate (but otherwise valid) messages.

24. Confidentiality • Does not require data confidentiality. Assumes that there is no threat of an eavesdropper or no loss if an eavesdropper intercepts a message. • Requires weak encryption (breakable, but requires a focused attack). • Requires strong encryption (mathematically unbreakable within a reasonable amount of time).

25. Authentication • Does not require authentication. Assumes that the messages it receives are authentic and does not require an explicit verification of the authenticity of the messages or message source. • Requires that the source of the message be verified.

26. Key Distribution • Can support manual key distribution (e.g. each node is manually given a key during configuration). • Can support node-specific initial keys that are available on electronic media and can be used to initialize a host computer or gateway to communicate with the nodes. • Requires automatic/zero-administration key exchanges between any two nodes (e.g. requires an asymmetric cipher which is computationally impossible for most low-end systems).

27. Submit Survey • Please fill out the survey forms and submit them to the IEEE 1451.5 Study Group, so we can have a better understanding what end users need.

28. Any Questions?