Designing FPGA and AM based transceiver for IEEE applications

Transcription

1 Designing FPGA and AM based transceiver for IEEE applications Network of Embedded Systems Area TeCIP Institute - Scuola Superiore Sant'Anna - Pisa, ITALY CNIT - National Laboratory of Photonic Networks Pisa, ITALY

2 VLC introduction VLC (Visible Light Communication) New communication tech. using solid-state lighting Visible Light Wavelength between ~400nm (750 THz) and ~700nm (428 THz) General Characteristic 2/18 Visibility: Line-of-Sight Security: What You See Is What You Send Health: harmless for human body (if eye safe) Free, unlicensed spectrum No RF interference with electronic devices VLC can mitigates RF health concern

3 Devices used for VLC Transmitter device Receiver device Visible Light 3/18

4 Off-the-shelf white LED characteristics 4/18 B + Phosphor LED R+G+B LED ~40 Mb/s ~100 Mb/s

5 PD, APD, CMOS characteristics PIN photodiode -high speed reception up to 1Gbps Avalanche photodiode -very sensitive low noise reception CMOS Image sensor -simultaneous image acquisition and data reception 5/18

6 Possible VLC applications 6/18

7 Motivations: VLC inside ITS Traffic signals and vehicles are gradually changing from electric light bulbs to LED light. LED light infrastructure can enable V2V, V2I, and I2I communications at large scale and low cost. VLC may be a valuable option respect to RF in case of: - broadcast storm - platooning 7/18 Outdoor VLC challenges: - Mobility disturbs Line-of-Sight Optimize lighting positioning - Sunlight, artificial lights, smog Use optical filters and optimized electronics

8 Features of NoES-CNIT prototype Half-Duplex VLC device Low-cost Off-the-shelf components Standard-compliant: IEEE (MAC & PHY I) Vision: first step towards scalable and pervasive VLC units eligible to be easily integrated in more complex systems like ITS. 8/18

9 NoES VLC prototype: system overview ERIKA RTOS + μlight: MAC layer PHY management TX Control Board SPI C code firmware: PHY (encoding and transmission) 9/18 Transmitter RX Control Board ERIKA RTOS + μlight: MAC layer PHY management SPI Receiver C code firmware: PHY (reception and decoding)

10 Tools: SEED-EYE Board Wireless Sensor Network node for C-ITS In house developed (part of the IPERMOB ITS project) MCU: Microchip PIC32MX795F512L 80 MHz 512 K Flash ROM, 128 K RAM Interfaces: SPI, UART, I2C, CAN IEEE interface with Microchip MRF24J40MB RF transceiver IEEE interface for wired LAN communications 10/18

11 Error-free range measurements: BER Error-free communication was achieved up to 5.1 m Communications at 10.2 m showed some errors: BER < /18

12 IEEE Std VLC Personal Area Network (VPAN) device 7 Application 6 Presentation 5 Session 4 Transport 3 Network 2 Data Link 1 Physical ISO/OSI Layers 12/18 TCP/UDP IP Logical Link Control (LLC) Medium Access (MAC) Physical (PHY) IEEE 802 Standards IEEE device

13 IEEE Std : overview VLC Personal Area Network (VPAN) device 13/18 Standard for local and metropolitan area networks - Short-Range Wireless Optical Communication Using Visible Light MAC and multiple PHY layers: - PHY I (outdoor), - PHY II e PHY III (indoor) Data rate: kb/s (PHY I) Mb/s (PHY II, PHY III) Max MPDU: 1kB (PHY I), 64kB (PHY II, PHY III) Topologies: broadcast, star, p2p Beaconless and beacon-enabled mode Visibility and color function support Dimming and flicker-mitigation support

14 Transmission chain in IEEE devices transmitter Data frames from MAC FEC encoder RLL MODULATOR Transmitting channel Data frames to MAC FEC decoder DEMODULATOR receiver Run Length Limited (RLL) code is a bit mapping that provides DC balance, clock recovery, and flicker mitigation Forward Error Correction is accomplished by adding redundancy to the transmitted information using a combination of algorithms. 14/18

15 FEC in IEEE PHY I devices 15/18

16 Work in Progress (1/2) Transferring the Optical Transmitter/Receiver functions on a FPGA (HW architectures with parallel processing). 16/18

17 Work in Progress (2/2) Designing novel Forward Error Correction decoder IC with Associative Memories (by INFN) Address the issue of Line-Of-Sight between vehicles by new design of the optical components. Full Duplex System with full IEEE functions Implement the adaptation layer between IPv6 and IEEE to allow the access of VLC technology to the Internet of Things infrastructure. Implement the vertical handover between VLC and other media: R/F, IR, Promote the standard development of VLC for C-ITS at ISO and ETSI Working Groups 17/18

18 Thank you for your attention! Designing FPGA and AM based transceiver for IEEE applications Mariano Falcitelli