harrison chin, p.eng senior field applications engineer · app level retries sar and/or model calls...

GO BIG, GO FAST, GO HOMEWhen Mesh Network Design MattersHarrison Chin, P.EngSenior Field Applications Engineer

OVERVIEW

0102

0304

0506

Introduction Test Methodology Reasoning

Relevant Use Cases Test Results Conclusion

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WHAT IS A MESH NETWORK?A system of interconnected nodes which cooperatively transport data from one node to another.

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WHY USE A MESH NETWORK?

Maximize Area Coverage

Nodes extend the effective range

Maximize Reliability

Redundant travel paths for data

Minimize Security Risks

Operate as independent networks

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USER INTERACTIVE SYSTEMSLatency sensitiveUse cases• Home automation• Lighting control• Door bells• Digital assistants

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USE CASELIGHTING CONTROL• Users expect instantaneous

response• Within 100ms or less

• Users expect consistency• Groups of lights change

together

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LIGHTING CONTROL SPECIFICATIONS• Bytes of data per packet• State data• On/Off• Intensity

• Infrequent events• Minutes between

changes• Strict latency bounds

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OBSERVATIONAL SYSTEMSThroughput sensitiveUse cases• Process management• Office space

management• Asset tracking• Vertical farm

monitoring©

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USE CASEASSET TRACKING• Hundreds of physical assets• Data is required in a regular and

reliable basis• Location, temperature, motion• Timescale in seconds to minutes

• Operate under a variety of environmental conditions

• Straightforward to deploy in scale

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ASSET TRACKING SPECIFICATIONS• Dozens of bytes per packet• Location• Sensor data

• Periodic events• Seconds between asset updates

• Large volume of concurrent traffic• All node data is important

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Use Case Latency Throughput Reliability

Lighting Control ✓ ✓

Asset Tracking ✓ ✓

KEY PERFORMANCE INDICATORS

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• Average Round Trip Time - Latency• Request a response from a node and measure how long it took

• Aggregate Gateway Throughput - Throughput• !"#$%& '( $)*%+ &%,%-.%/ (&'# 011 !'/%+

*'*01 *-#% ('& 011 +",,%++("1 &%+2'!+%+

• Average Success Rate - Reliability• !"#$%& '( &%+2'!+%+ &%,%-.%/*'*01 !"#$%& '( &%3"%+*+

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HOW DO WE MEASURE PERFORMANCE?

PING TESTING• Gateway-based Architecture• Phone/switch is the gateway for lighting• Cellular/Satellite/Hardline bridge for Asset tracking ©

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PING TESTING

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TEST FRAMEWORK

Bluetooth Mesh ANT BLAZE

nRF52832-based modules nRF52832-based modules

Certified nRF BLE Mesh 3.1.0 ANT BLAZE Libraries

Test software provided by Nordic Semiconductor Test software provided by Garmin

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TRAFFIC PATTERNSSingle Ping• One node responds• Lights…visible feedbackGroup Ping• 10 nodes respond• Many sensors relaying data to gateway

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LAYOUT - DENSE - 30 NODES

RelayNodeGateway

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DENSE – 30 NODESTest Setup• ~4m spacing between nodes• ~8m spacing between relays• 4 relays in 30 nodes

• Kitchen Environment• Reduced BLE ADV Traffic

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132.53

25.57

5.49 8.6619.97

33.33

138.66

192.39

0

50

100

150

200

250

5-Byte Single Ping 25-Byte Single Ping 5-Byte Group Ping 25-Byte Group Ping

Throughput (B/s)

Aggregate Throughput at Gateway (B/s)

Bluetooth Mesh ANT BLAZE

DENSE – 30 NODES

38

978

2592

7162

250

750

236

994

0

1000

2000

3000

4000

5000

6000

7000

8000

5-Byte Single Ping 25-Byte Single Ping 5 Byte Group Ping 25-Byte Group Ping

Round Trip Time (ms)

Average Round Trip Time (ms)

Bluetooth Mesh ANT BLAZE

DENSE – 30 NODES

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77.66

99.03

69.41

53.43

100 100 100 100

0

20

40

60

80

100

120

5-Byte Single Ping 25-Byte Single Ping 5-Byte Group Ping 25-Byte Group Ping

Success Rate (%)

Average Ping Success Rate (%)

Bluetooth Mesh ANT BLAZE

DENSE – 30 NODES

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LAYOUT – SPARSE – 30 NODES

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SPARSE – 30 NODESTest Setup• ~10m Spacing• 30 Nodes Total• All Relays• 100 Test Cycles• Increased BLE ADV Traffic

Logan and Rainer*May not be a representative

depiction of all interns

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76.3

32.28

13.764 10.6714

4147

120

0

20

40

60

80

100

120

140

5-Byte Single Ping 25-Byte Single Ping 5-Byte Group Ping 25-Byte Group Ping

Throughput (B/s)

Aggregate Response Throughput at Gateway (B/s)

Bluetooth Mesh ANT BLAZE

SPARSE – 30 NODES

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65.7

930.1

1241

3624

357610

1298 1360

0

500

1000

1500

2000

2500

3000

3500

4000

5-Byte Single Ping 25-Byte Single Ping 5-Byte Group Ping 25-Byte Group Ping

Round Trip Time (ms)

Average Round Trip Time (ms)

Bluetooth Mesh ANT BLAZE

SPARSE – 30 NODES

86.033

97.4333

70.17

29.17

100 100 100 99.6

0

20

40

60

80

100

120

5-Byte Single Ping 25-Byte Single Ping 5-Byte Group Ping 25-Byte Group Ping

Success Rate (%)

Average Ping Success Rate (%)

Bluetooth Mesh ANT BLAZE

SPARSE – 30 NODES

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Latency

Throughput Reliability

You can only pick two.

TRADE-OFF TRIAD!= CONJOINED TRIANGLES OF SUCCESS

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WHY? SHARING A LIMITED RESOURCE… AIR TIME• Fundamental contention between…• Keeping nodes busy with required data transfers• “Throughput”

• Keeping nodes available to listen for new data requests• “Latency”

• Keeping nodes aware of failed data transfers• “Reliability”

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Parameter Bluetooth Mesh ANT BLAZE

RF channel N/A, ADV channels 78 channels, Up to 3

App level retries SAR and/or model calls Library calls in app

Proxy ADV Interval Modify for density N/A, As needed

Transmission interval Modify for concurrency N/A, Built-in

Transport layer repeats Modify for interference N/A, Built-in

Relay count Modify for coverage N/A, All relay

Time-to-live Modify for coverage N/A

Bearer layer repeats Modify for interference N/A

TUNING PARAMETERS FOR THE RIGHT BALANCE

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LIGHTING CONTROL RE-IMAGINED

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BLUETOOTH MESH TIME DOMAINLIGHTING CONTROL

Gateway

Node 1

Node 2

Node 3

Node …

Time

© 2018 Garmin Canada

Newly published data0-20ms before

broadcast

Minimal activity between new data events

Node N

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ASSET TRACKING RE-IMAGINED

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BLUETOOTH MESH TIME DOMAINASSET TRACKING

Node 2

Node 3

Node …

Node N

Time

© 2018 Garmin Canada

Gateway

Node 1

Concurrent message collisions

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BLAZE BROADCAST TIME DOMAIN BOTH USE CASES

Gateway

Node 1

Node 2

Node 3

Node …

Steady state of activity between new data events

Regular interval between transmissions

62.5-500ms

© 2018 Garmin Canada

Newly sent dataWaits for next period

Node N

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“CONTEXT IS FOR KINGS”• What are your requirements?• Latency• Throughput• Device count

• Where are the nodes being deployed?• Commercial• Residential• Industrial

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- Hint: “Starfleet” Captain

CONCLUSION

• Is ultra-low latency required?• Data suggests look into Bluetooth Mesh

• Is increased throughput more important?• Data suggests look into ANT BLAZE

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QUESTIONS?

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