Embedded networks combining Power Line and Wireless communications

Transcription

1 Embedded networks combining Power Line and Wireless communications WSPL2008, Thessaloniki, 2&3/10 / 2008 Fabienne Nouvel, Patrice Maziero IETR, UMR CNRS 6164,INSA of Rennes e.mail : fabienne.nouvel@insa-rennes.fr UMR

2 Summary - Today s cars : how do they like? Today embedded multiplexing and networks Description of PLC automotive channels Use of Homeplug V1.0/AV for PLC in vehicles Wireless solutions : is it possible? Conclusion 2

3 Today s cars : how many networks? How do the cars look like? Networks with various applications 3

4 Today s cars : how many networks? The future applications and needs : high data rate and plug&play systems TV display ipod GPS display Network Network Backbone Backbone Inter-domain Gateway Car Area Network Internet access DVD player Movie storage Rear view camera 4

5 Summary - Today s cars : how do they like? Today embedded multiplexing and networks Description of PLC automotive channels Use of Homeplug standard for vehicle PLC Wireless solutions Conclusion 5

6 The most representative networks? INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES 3 most common networks : LIN, CAN, Flexray Additional networks : MOST, IDB

7 The most representative networks INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES 3 most common networks : LIN, CAN, Flexray 7

8 The most representative networks INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES LIN (1998) used by sensors and actuators - Short simple frame Low cost but low data rate Number of nodes : 16 slave per master Questions vs plug and play nodes: what happens when a new node is added / suppressed? What about the data rate? 8

9 The most representative networks INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES CAN (1985) Higher data rate ( > 1 Mbps/s) with short frames (medium complexity) Implemented for Class B and C CSMA/CA masters & masters Questions vs plug and play nodes: CSMA/CA and real time application? What s about the data rate for multi-media application? Two wires => more complex to route 9

10 The most representative networks INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Flexray (2000) Highe data rate ( > 10 Mbps/s) with long frames ( more complex) Implemented on one or two channels Master TDMA strategy static and dynamic time slot Questions vs plug and play nodes: What s about plug and play nodes? Two wires => fault tolerance but more complex to route High cost 10

11 The most representative networks INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES 3 most common networks : LIN, CAN, Flexray 11

12 The most representative networks INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Advantages Ability to connect embedded ECU using different data rate Different fault tolerant Devices are available Drawbacks Not convenient for plug and play nodes Specific additional wires Power consumption? Alternative Solutions : Wired/Power line or/and Wireless solutions 12

13 Summary - Today s cars : what, who, how? Embedded Solutions Description of PLC automotive solution Use of Homeplug standard for vehicle PLC Wireless solutions Conclusion 13

14 PLC automotive channels/wires INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES What is Power Line solution? Power and data on the same cable Preserve the number of wires while increasing the embedded functions Uses multiplexing techniques : TDMA - CSMA/CD Modulations : OFDM, widely used for many applications ( xdsl, HomePlug,..), good efficiency, robust against fadings High data rate transmission Standards for domestic applications for indoor access : HomePlug, P1901, HPAV, Panasonic 14

15 PLC automotive channels/wires INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Steps for PLC communications : Channel measurements Coupling on DC Data rate measurements Configuration of measurements Measurements in the [0-30] MHz band on a Peugeot 407 Different measurement points, in the body area and rear trunck Different cases : car stopped, in motion, ECU ON/OFF, urban & rural trafic Spectrum analyzer connected through a transformer ( DC isolated) Network analyzer Results in term of Bandwidth Noise ( impulsive noise, large and narrow band, background) Insertion loss Variation of the channel according the state of ECUs 15

16 PLC automotive channels/wires INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Test bed Engine area H Blue wire Body area trunck I lights AR F Lighter socket E socket 12 V Alim ECU1 - + B ECU1 Alim ECU3 ( Fil bleu) D ECU3 Alim ECU2 (Blue wire) A socket12v trunck ECU2 G 16

17 PLC automotive channels INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Results of channel measurements Max. attenuation Linear attenuation Frequency selective channel Variation of the transfer function due to the value of the loads in the vehicle -0.5 db / MHz [500 KHz, 70 MHz] bandwidth Signal attenuation vs frequency : 0.5 db/mhz Measurements carried out by TELICE and IETR laboratories 17

18 PLC automotive channels Results of channel measurements : additional results Channel is not adapted to 50 Ω The length of the wires and loads involve attenuation, non- adaptation, and reflections 18

19 Summary - Today s cars : what, who, how? Embedded Solutions Description of PLC automotive channels Use of Homeplug standard for vehicle PLC Wireless solutions Conclusion 19

20 Home Plug V1.0 and AV Homeplug parameters Standard for indoor PLC communications 14 Mbps data rate IP applications Multi-carriers modulation ( OFDM ) 128 sub carriers / 84 used for data [0/4.. 25/30 MHz] bandwidth DBPSK, QPSK, Robot modulation Concatenated Viterbi and RS coding Many products are available based on the Intellon chipset /Spidcom 20

21 Home Plug V1.0 and AV Homeplug spectrum over 220 V AC and voltage synchro 128 sub carriers 84 carriers for data 21

22 Home Plug V1.0 and AV Spidcom SPC200-E Master/slave TCP/IP data flow Bandwidth 2 30 MHz, 7 subbands of 4 MHz, notches Bit coding : BPSK, QPSK, QAM16, according to the SNR for each sub-band, 128 channels used/not used, FFT 256 Pilots for channel estimation and synchronisation 22

23 Home Plug V1.0 and AV Spectrum analysis => some attenuation Frequency / MHz 23

24 Home Plug V1.0 and AV Data rate measurement 2 laptops connected through the PLC modem Motor ON/OFF, equipments ON/OFF TCP and UDP data flow JPERF and Ixchariot tools Jperf : client and host, settings : TCP window, segment size Ixchariot : two clients and a host, settings : TCP/UDP window, segment size Modems connected on the DC power line through a transformer an filter 24

25 Home Plug V1.0 and AV Lower data rate when motor is ON and car in motion Up to 8 Mbps Enhancement according to TCP/IP settings Average Data rate bps/s) BLUE : motor OFF Orange : motor ON A-B A-D A-H H-B H-D 25

26 Other wired solutions Yamar : CAN and power : DCAN250 Packet data: 250Kbps, 16 nodes Can interface Modulation DQPSK Collision resolution, coding, power save Packet size: User defined HomePLug AV Homeplug enhancement : higher data rate Bandwidth : [4-30 Mhz], Turbo coding, Tone ordering ( bit loading ) Many products available Coax solution : expensive 26

27 Summary - Today s cars : what, who, how? Embedded Solutions Description of PLC automotive channels Use of Homeplug standard for PLC in vehicles Wireless solutions : that the question Conclusion 27

28 Wireless solutions : the usages INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Advantages No wires Easy to install => plug and play application Easier to replace, to take from one car to an other one Many questions Which Bandwidth? Which data rate? Which solution already in use? What s about the level? disturbances What s about the channel, the antennas? What s about body effect? 28

29 Wireless possible solutions INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Focus on 3 potential solutions in the 2.4 GHz band : Bluetooth, Wifi, ZigBee Protocole Zigbee Bluetooth Wi-Fi Wireless USB IEEE /Modulation Ghz et 800 MHz DSSS Ghz OFDM a/b/g 2.4 Ghz - OFDM UWB- MB- OFDM and DS Architecture Master/slave and master Master/slave and master Ad-hoc and infra Master/slave and master Media access CSMA/CA CSMA/CA CSMA/CA TDMA Nodes number Data rate 250 Kbps 1 Mbps Mbps 55 à 480 Mbps Distance/power 100 m m 300 m 10 m 29

30 First Step : Channel measurements INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Configuration of measurements Measurements in the [ ] GHz band on the same car Different points : body area and rear trunck Different cases : car stopped, in motion, ECU ON/OFF, urban and rural trafic Network analyzer and Spectrum analyzer connected to the antennas Results in terms of Bandwidth Noise (radio, GSM, UMTS, WLAN, ) Insertion loss No Variation of the channel according the state of ECUs H E1 F E2 A 30

31 Channel measurements Results of channel measurements in the 2.4 Ghz band : car stops Transfert Channel for different cases dbm AE1 AE2 AF AH f (MHz) 31

32 Channel measurements Results of channel measurements in the 2.4 Ghz band : car driving Transfert Channel when the car is in motion dbm Stop OFF STOP- Motor ON Driving Breaking / Driving Equipment f (MHz) 32

33 Second step : Configuration for data rate INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES g / infrastructure configuration Dungle USB D-Link DWL-G b/g Routing node WiFi BeWan (802.11g) WiFi Antenna - 2,4GHz PC1 : Server Routing node BeWan PC2 : Client Data rate measurement Spectrum analyser 33

34 Data rate measurements INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES g / infrastructure configuration H I Jperf_D-Link Data rate for 4 configurations F D E A Up to Mbps Data rate Kbps) AH AD AE AH_haut Enhancement according to TCP/IP settings Stopped Motor on In motion motion equipements ON Motion+breaking Antenna position is important 34

35 Wireless solutions INSTITUT D ÉLECTRONIQUE ET DE TÉLÉCOMMUNICATIONS DE RENNES Additionnal studies Comparison with PLC : Frame structure, modulation technique, coding noise, data rate Tests with other wireless systems : wireless usb, additionnal nodes Switch between PLC and Wireless => Reconfigurable node => redundancy => when do the ECU switch => frame compatible with the 2 systems EMC measurements, power limitation Choice of the antenna : small, easy to install 35

36 Conclusion Power Lines and wireless communications : it can be possible Todays embedded solutions allow middle data rates PLC and wireless can allow higher data rate and plug &play OFDM modulation for both Improvement : coupling techniques, power, bandwidth Additionnal measurements : wireless systems, additional nodes This work was supported in part by the ANR contract, CIFAER Project, in cooperation between two manufacturers, ATMEL, GEENSYS, and two universities, IRISA and IREENA. It has been done within the cluster Pôle Automobile Haut de Gamme. 36

37 Embedded networks for automotive : Power Line and Wireless communications WSPL2008, Greece, 2&3/10 / 2008 Questions? UMR