pdr keeping the secret

SDP 11 PDR Team Goeckel

Group: Adebayo Adeyemi, Joseph Hayward, Mark Kohls, Simon McAuliffe

Advisor:Dennis Goeckel

PDRKeeping The Secret

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What is encryption?

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So, What’s wrong with it? Encrypted transmissions can be recorded These recording can be broken Information can be sensitive for years Computers are getting faster and faster

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Applications Military

• Out in the field• Missions only last less than 12 hours• Sensitive can be transmitted• Many people out in the field• No knowledge of where the enemy may be

Commercial• Keep people from recording inside building• Keep signal from being recorded from outside building

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Competitors Direct link Trunked radio system Frequency hopping spread spectrum.

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Direct Link

Marine tactical data system.

Large Directed Antenna Heavy, Expensive

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Trunked SystemPre-known shared key needed

Easily recorded with a spectrum analyzer

Even UMASS has one

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Frequency Hopping

A pre-known shared key for communicationThe security can be easily broken

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System Requirements

Battery life of at least 12 hours Receive and transmit Operate while walking Operate up to 300 meters.

• Receive signal with 95% success rate. Voice Transmission Bandwidth Maintain secure communications

• Less than 10% interception rate Handheld and less than 2lbs.

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Proposed Solution

Step 1: Send test signal to desired

radio.

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Proposed Solution

Step 2: RX radio sends back reply signal. Friends measure this

signal strength.

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Proposed Solution

Step 3: TX radio sends out

message. Friends not in range

transmit noise.

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Hardware Requirements Receiver with Signal Strength Indicator Transmitter without interference filtering Battery Power 300 meter Range Narrow band FM

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Radio Diagram

Antenna

Receiver

Transmitter

Microcontroller

Microphone

Speaker

Transceiver

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Radio ChoiceLinx Technologies HP3

RF Solutions T5/R5 434

Radiometrix BiM3A

Received Signal Strength IndicatorNo Interference FilteringFully IntegratedProgrammableBattery PowerFrequency Band (MHz) 900-928 433 900-928

Range (m) 300 300 200

Choice: Linx Technologies HP3

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Software Requirements

RX Radio

RX Radio

RX Radio

TX Radio

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Design Challenges Noise

• Appropriate Signal Threshold• Duration for transmission

Variable transmission strength Making overall system compact

• SMD vs. Through Hole components Demonstrate functioning system

• Computer display of radio activity

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MDR Deliverable The goal for MDR will be to demonstrate measurement of receive signal and transmitting noise.

Step 1: Send test signal to desired radio.

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MDR DeliverableThe goal for MDR will be to demonstrate measurement of receive signal and transmitting noise.

Step 2: RX radio sends back reply signal.

Friends measure this signal strength.

20SDP 11 PDR Team Goeckel

MDR DeliverableThe goal for MDR will be to demonstrate measurement of receive signal and transmitting noise.

Step 3: TX radio sends out message. Friends not in range transmit

noise.

21SDP 11 PDR Team Goeckel

Questions?