Authors: Xiuming Zhu 1, Song Han 1, and Aloysius Mok 1 1 The Department of Computer Science, the University of Texas at Austin Deji Chen 2, and Mark Nixon 2 2 Emerson Process Management Presenter: Yi-Hung Wei 1

 Wireless Personal Area Network(WPAN) ◦ IEEE ◦ ZigBee  Industrial Wireless Network ◦ Timing requirement, reliability, security concerns ◦ WirelessHART  IEEE  Hardware challenges IEEE ZigBee WirelessHART FreeScale MC1322

Real-Time ◦ TDMA Technology ◦ Centralized Network Management Reliability ◦ Channel Hopping and Channel Blacklisting ◦ Mesh Networking Security ◦ Data Integrity on MAC Layer ◦ Data Confidentiality on the Network Layer IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 Hardware Challenges  Development of WirelessHART ◦ Early Prototype ◦ Wi-HTest ◦ Current System  Future work IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 TDMA data link layer  Timeslot: 10ms  TsTxAckDelay: 1ms  Security mechanism  MAC layer related processing  Authenticate the incoming message  Generate authentication code IEEE 9th International Conference on Industrial Informatics, INDIN'2011 WirelessHART Slot Timing

IEEE 9th International Conference on Industrial Informatics, INDIN'2011 DeviceTiny Gateway Large Gateway Neighbors Superframes1612 Total # of Links Graphs Total # of Graph- Neighbor pairs Packet Buffers Total size6,112 bytes5,716 bytes11,6356 bytes Data Link Layer Minimum Requirement DeviceTiny Gateway Large Gateway Sessions Correspondent Device 1 per Session 16 Transport2 per Session30510 Routes Source-Routes2 Timetables16N/A Total size1,106 bytes2,910 bytes36,508 bytes Network Layer Minimum Requirement

 WirelessHART network is a synchronized network ◦ 10ppm drift rate of the MCU clock. ◦ The maximum tolerance for drift is 1ms  Synchronize every 50secs between master and slave.  If the chain from time source is longer, the time to sync is shorter. IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 Hardware Challenges  Development of WirelessHART ◦ Early Prototype ◦ Wi-HTest ◦ Current System  Future work IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 chips available in early day IEEE 9th International Conference on Industrial Informatics, INDIN'2011 Manufact urer ChipMCUMax txFlashRAM EmberEM25016bit 24MHz 5dBm128k5k FreeScaleMC132148bit 40MHz 3dBm60k4k JennicJN512132bit 16MHz 0.4dBm64k (ROM) 96k TI- Chipcon CC24308bit 32MHz 0.6dBm128k8kb * J. Song, S. Han, A. K. Mok, D. Chen, M. Lucas, M. Nixon, and W. Pratt, WirelessHART: Applying Wireless Technology in Real-Time Industrial Process Control. Real-Time Technology and Applications Symposium, * J. Song, S. Han, X. Zhu, A. K. Mok, D. Chen, and M. Nixon, Demo of a Complete WirelessHART Network, ACM SenSys 2008 Demo Session.

 Some observations ◦ MCU  Only tested with 20ms, 40ms timeslots ◦ Software AES engine  MC1321 software AES engine ◦ Transmitter  Maximum programmable transmit power is only 3dBm ◦ RAM  4KB is too limited IEEE 9th International Conference on Industrial Informatics, INDIN' ms Hardware AES 10dBm

 Hardware Challenges  Development of WirelessHART ◦ Early Prototype ◦ Wi-HTest ◦ Current System  Future work IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 Motivation ◦ Assure the standard compliance of WirelessHART devices ◦ Thorough tests for each layer of WirelessHART stacks are needed ◦ Help vendors avoid expensive product recalls and technical support costs  Hardware architecture ◦ FreeScale MC1320  Physical layer, data link layer  ColdFireV1 MCU, 32-bit, 50.33MHz  128KB FLASH  16KB RAM ◦ PC Box  Network layer S. Han, J. Song, X. Zhu, A. K. Mok, D. Chen, M. Nixon, W. Pratt, and V. Gondhalekar, Wi- HTest: Compliance Test Suite for Diagnosing Devices in Real-Time WirelessHART Network. Real-Time Technology and Applications Symposium, 2009.

 Clock precision ◦ ±2.5ppm oscillator as the external clock input ◦ The drift is consistent in fixed environment  It is possible to compensate it with software  Security computation ◦ CCM algorithm is still expensive  Parallel decoding ◦ Pre-compute acknowledgement message  Flash Memory Usage IEEE 9th International Conference on Industrial Informatics, INDIN'2011 Compone nt Bootload er CDC-USB driver Encryptio n engine System library Operatin g system WirelessHAR T stack Total 3K11K20K11K7K34K86K

 Hardware Challenges  Development of WirelessHART ◦ Early Prototype ◦ Wi-HTest ◦ Current System  Future work IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 Hardware ◦ FreeScale MC1322  32-bit 24MHz ARM7 MCU  22mA typical RX current draw  29mA typical TX current draw  Extensive sleep mode  MAC accelerator  Advanced AES hardware engine  Software ◦ Complete WirelessHART mesh networking functionality IEEE 9th International Conference on Industrial Informatics, INDIN'2011

17  10 devices and 1 AP in the system  Devices publish data to GW with different sampling rates (1sec – 8sec)  Retry happens but no packet loss is detected

 Hardware Challenges  Development of WirelessHART ◦ Early Prototype ◦ Wi-HTest ◦ Current System  Future work IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 Memory  96K Flash for WirelessHART stack  24K RAM for the data section  More space for application layer  Clock  High precision  Maintains precision when sleep  Power  More sensitive receiver  More deeper sleep mode  Encryption  Hardware AES engine or fast MCU  Open AES engine IEEE 9th International Conference on Industrial Informatics, INDIN'2011

 Chronicle our work and provide our experience of the system design challenge of WirelessHART ◦ Prototype ◦ Wi-Htest ◦ Complete WirelessHART mesh network  Provide hardware requirement for future industrial wireless embedded network chip IEEE 9th International Conference on Industrial Informatics, INDIN'2011

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