Transcript Slide 1

Sensor Network Research Group University of Massachusetts, Amherst Ultra-Low Power Data Storage for Sensors

Gaurav Mathur, Peter Desnoyers, Deepak Ganesan and Prashant Shenoy Motivation:

Number of flash memory storage options exist for sensors

NOR flash (Mica, Mica2, Telos)

Multimedia cards – MMCs (RISE)

 

NAND flash (UMass Mica2 adapter board)

No comprehensive empirical comparison

of the energy-efficiency of

storage alternatives for sensor devices Many applications require energy-efficient, high-capacity storage

Camera sensing

Acoustic sensing What is the most energy-efficient storage platform How does the energy cost of What are the implications storage compare to that of for sensor devices ?

computation and communication of an ultra-low power storage subsystem on sensor net design ?

?

Comparison Study of Storage Technologies Toshiba Parallel NAND flash adapter Mica2 Atmel serial NOR flash MMC adapter TelosB STM serial NOR flash

 

Compare MMC, NOR & NAND flash technology Measure active & sleep mode power consumption

Comparison of the per byte cost of operations (in μJ)

Device

Mica2 NOR TelosB NOR

Read

0.26* 0.056*

Write

4.3* 0.127*

Erase

2.36

0.185

Total

6.92

0.368

Hitachi MMC 0.144

0.659

0.0033

0.806

Parallel NAND 0.004* 0.009* 0.004

0.017

* Without ECC.

Cost of performing ECC in software is approx 0.026μJ/byte Parallel NAND flash

is

21 times

Telos STM flash and

407 times

more efficient than Mica2 Atmel flash.

Implications of Low Power Storage

 

Challenges conventional wisdom of trade-offs

Computation

<

storage

<<

communication

Energy-efficiency of NAND flash enables ultra low power,

almost infinite storage

(~1 GB) High-capacity, Low-power storage impacts the following sensor application domains by supporting:

Higher degree of

local data archival and indexing

, which

supports

in-network query processing

Use of history for efficient

network-level compression Impact on Radio Transmission Costs Comparison of computation, communication and storage costs

Energy Ratio

TI MSP430 instruction

0.0008

1

Toshiba NAND read

0.004

5

Toshiba NAND write

0.009

11

CC2420 Radio Tx

2.6

3250

CC2420 Radio Rx

2.2

2750

Storing data on

NAND flash

is

369 times

more energy efficient than communication

  

BMAC uses a per-packet preamble that leads to a high per-packet transmission cost Instead, store packets on NAND flash & batch transmit Can lead to a

58x reduction

in communication costs !

http://sensors.cs.umass.edu/projects/essense