Review on the Proposed Survey of Wireless Sensor

Requirements

Presented byDavid Perrussel

Naval Surface Warfare Center – Dahlgren Division

Dahlgren, VAMay 20, 2002

Don’t Get Stuck In Requirements

Goal: A WirelessIEEE 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

Goals for P1451.5 SGA standard or group of standards for

wireless sensor systemsUse IEEE 1451 as a basisMake use of 1451’s TEDS (transducer

electronic data sheet)Explore various wireless media

conceptsInteroperability

DefiningRequirements

Requirements need to be defined before standard can be made

Must fit users needsMust allow for interoperability

Don’t Get Stuck In Requirements

Ask For User NeedsWhat are the user needs?Conduct a survey of users and

developersCombine results to help make

standard

User Needs SurveyData/Bit rates per network access node

Rate for periodically transmitted messages Burst traffic

ApplicationRangeNumber of units in a given area

(network)Latency

User Needs SurveyExpected Battery LifeDesired Battery CapacityIntrinsic SafetyAntenna size – Internal or External

User Needs SurveySecurity

Data Integrity Data Freshness Confidentiality Authentication Key Distribution

  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

             

               

Payl

oad

Bits

Per M

essa

ge

Table 1 - Rate table for periodicallytransmitted messages

Table 2 – Burst Traffic

Bits per message

Typical messagesper hour

   

   

   

ApplicationPlease provide a very brief

description of the application.This information will be used to get

an idea of how the applications break down.

RangeThe study group needs an idea of the

typical distance between a transmitter and a receiver.

Table 3 – Range Definitions

Range description

Range

Very Short < 10 meters

Short 10 – 100 meters

Medium 100 – 1000 meters

Long >1000 meters

Number of Units In An Area (Network)

Please provide an estimate of the number of remote units connected to a single network access point.

LatencyThe 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.

BatteriesExpected 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

Intrinsic SafetyIs intrinsic safety a requirement?

Antenna RequirementsInternal or External?

SecurityData IntegrityData FreshnessConfidentialityAuthenticationKey Distribution

Data IntegrityDoes 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).

Data FreshnessDoes 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.

ConfidentialityDoes 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).

AuthenticationDoes 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.

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).

Submit SurveyPlease 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.

Any Questions?