LoRa/LRSC. Wireless Long Range Network for M2M Communication

Transcription

1 Marcus Oestreicher LoRa/LRSC Wireless Long Range Network for M2M Communication

2 Overview Introduction to LoRa IBM LRSC - Long Range Signaling & Control LoRaWAN Specification Demo

3 Introduction IBM Research Zurich BlueZ Business Computing Group Cryptographic Software, JavaCard, ZTIC Embedded Systems, LRSC

4 M2M/Internet Of Things Application Scenarios Environmental Monitoring Warning systems: Forest fire detection Air pollution, water quality, soil conditions (smart agriculture) Wildlife and habitat monitoring Infrastructure Management Monitoring of urban and rural infrastructures Structural health: Monitoring of vibrations and material conditions in buildings/bridges Smart lighting: Intelligent and weather adaptive lighting in street lights Location tracking: e.g. of (missing) e-bikes on demand Advanced Metering Infrastructures (Smart Grid) Smart electricity meters, gas meters, heat meters, and water meters Balance supply and consumption Two-way communication Transport Systems Smart traffic control, smart parking Home Automation, Healthcare Systems

5 Internet Of Things Communication Technologies GSM/GPRS as a fit? High data rates, bidirectional Long range, broadly available as infrastructure service - Requires SIM card for each end-device - Not particularly energy-efficient - Coverage is insufficient for specific types of applications - Cost is (prohibitively) high for specific types of applications star WiFi, as a fit? High data rates, bidirectional No SIM card required for each end device - Not universally available as infrastructure service - Short range requires complex mesh networking to cover larger areas mesh 100% 75% 50% SIM SIM-less (France Estimation) 25% 0%

6 Long Range Radio Semtech LoRa TM Secured bi-directional sub-ghz link Range > 2km in urban areas, > 10km in rural areas (i.e., reaches meters in basements) Typically operated in ISM band Spread-spectrum approach whereby different spreading factors don t interfere with each other Data rate between 0.3kbps (SF12) and 10kbps (SF7), 100kbps via FSK Dynamically trades data rate against range 10mA RX current, 100nA sleep current Gateways can receive multiple messages from different end devices simultaneously End devices rotate through alternating frequencies when transmitting Capacity can be incrementally increased by reducing cell size Compared to GSM/GPRS Better penetration and range (only ~1/4 to 1/3 of gateways required to cover same area) Lower power consumption for battery operated end devices Lower data rate with a strong uplink bias w/ dynamic link-rate adaptation Cost advantage

7 LoRa Neuchatel Range Test A B C D +14dBm 868Mhz No filters Point Range Modulation Datarate Sensitivity Bandwidth D 15.2km LoRa bps -137dBm 125kHz C 8.1km LoRa-8 3.3kbps -127dBm 125kHz B 2.2km FSK 4.8kbps -111dBm 50kHz A 1km FSK 50kbps -106dBm 200kHz

8 LRSC Long Range Signaling & Control Large Scale LoRa Network Central management by network operator (Telcos) Federated network supporting device and application diversity Low entrance barriers for application providers End-to-end security Scalable network capacity Roaming

9 IBM LRSC Infrastructure Overview IP communication (TCP/IP, MQTT, ) Billing System GW end devices GW AA- -01 Application Router App Network Server GW CA Application Router App GW FF IBM LRSC LoRa wireless communication

10 LoRaWAN Specification End Devices Class A devices: Bidirectional communication, Random access Two short receive windows after a send operation Data messages with/without confirmation Data messages encrypted and MICed Pre-Personalisation or Over-the-air Activation (Join procedure) MAC management commands/responses piggypacked (e.g. datarate adaptation) EU-/US-/..- MAC variations: duty cycles, frequencies, spread factors.. Class B devices: Pingable' devices Device and network can schedule receive slots Receive slots are based on the time information contained in beacons Beacons are broadcasted by all gateways within a network Class C devices: Always listening

11 LoRaWAN Specification Uplink-/Downlink-Messages Random Access Transmit/Receive Windows Transmit RX1 RX2 - Minimum receive window length: downlink preamble length - RX1: frequency and data rate of transmit operation - RX2: configurable frequency and data rate - Tx/Rx windows may not overlap Device expected to alternate transmit frequency Depends on strategy and band regulations

12 LoRaWAN Specification End-Device-Activation Required device state for communication: Application Identifier (AppEUI) Device address (DevAddr) Bit# DevAddr NwkID NwkAddr Session keys Network session key (AES-128) Application session key (AES-128) Activation schemes: Activation by personalization Over-The-Air activation Application device key (AppKey), device EUI (DevEUI)

13 LoRaWAN Specification End-to-End Security/Communication No network-wide keys and keep application payload private from network operator JOIN REQUEST calculate DevNonce DevID, DevNonce NwkS DevID, DevNonce AppR get AppKey D calculate AppNonce calculate AppSKey A, NwkSKey N JOIN ACCEPT calculate AppSKey [AppNonce]D [AppNonce]D, NwkSKey App DATA EXCHANGE calculate and verify MIC with N encrypt and decrypt payload with A ( [payload]a )N [payload]a payload App MAC COMMAND calculate and verify MIC with N encrypt and decrypt commands with N ( [commands]n )N Legend uses RFC 4493 and AES128 encrypted with key K: [ ]K MIC calculated with key K: ( )K

14 LoRaWAN Specification EU MHz ISM Band ETSI bands and sub-bands: Edge Frequencies [Mhz] Field / Power Spectrum Access Bandwidth [Mhz] dBm 0.1% 7Mhz dBm 1% 600kHz dBm 0.1% 500kHz dBm 10% 250kHz dBm No req. 300kHz dBm 1% 300kHz Minimum set of channels (Join Request) Modulatio n Bandwidt h [khz] Channel Frequency [Mhz] FSK Bitrate or LoRa DR / Bitrate Nb Channels Duty cycle LoRa SF7 SF12 / kbps 6 <0.1% Channel updates in Join Response/Mac Command

15 LoRaWAN Specification US ISM Band Channel plan: Upstream 64 channels (LoRa 125KHz, SF7-10, MHz) Upstream 8 channels (LoRa 500KHz, SF8-12, MHz) Downstream 8 channels (LoRa 500KHz, SF7-12, MHz) uplink channels 8x downlink channels Regulation implications Dwell time, no duty cycle limitations Devices always hop through frequencies Transmit power specification for channels

16 Q&A Q&A