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“802.15.4 Powered Distributed Wireless Smart Cameras Network”.
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“802.15.4 Powered Distributed Wireless Smart Cameras Network” Erik Ljung, Erik Simmons Philips IC-Lab, Building SFJ-6, Glaslaan 2, 5616 LW Eindhoven, The Netherlands+31-(0)40-2732330 {ljunge,simmonse}@iclab.ce.philips.comAlexander Danilin, Richard Kleihorst, Ben Schueler Philips Research Europe, High Tech Campus 5,5656 AE, Eindhoven, The Netherlands+31-(0)40-2742366 {alexander.danilin, richard.kleihorst, ben.schueler}@philips.com Paper Review By Atilla Filiz a.filiz@student.tue.nl Naveed A. Abbasi n.a.abbasi@student.tue.nl Presented at Workshop on Distributed Smart Cameras (DSC 2006) October 31, 2006 Boulder, CO, USA held in conjunction with ACM SenSys 2006
Introduction • WiSN • Characteristics • IEEE 802.15.4 • ZigBee • WiCa • Hardware Architecture • Software Architecture • Future Work
WiSN • Sensor Networks vs. Networks • Power • Communication Abilities • Processing, Storage • Distributed Imaging Nodes • Individual Image Processing • Combined Resources • 3-D
WiCa • WiCa Hardware • Software Architecture • Packet based approach • WiCa OS • Application Execution • PC Side Control • Results • Future Work
WiCa Hardware • IC3D :Successor of Xetal -I • Atmel 8051 • Dual Port RAM • AquisGrain
Software Architecture • Software Stack of 4 modules • 1st Controls IEEE 802.15.4 MAC layer • Setup and maintain the network forward and receive data • Three Types of Packets • Communication Packets • ISP Packets • WiCa OS Packets • AG Modules have UID.. WiCa doesn’t Have UID • AG Modules also Have NID, assigned by Network Controller • New NID on reset, Same UID always..
Software Architecture (2) • 2nd module controls kernel • Kernel and High level in 8051 • Round Robin + Enable Disable switching • Kernel high priority • Disables task switching ability when running and otherwise • Packets in/out of application • Template…. And easily extendible..
Software Architecture (3) • 3rd and 4th module control the Pixel Level and high Level Processing (together in IC3D and 8051) • All protocols chained together • 1st 3 Form WiCa OS • High level processes com with low level via I2C
Packet Based Approach • Information flow in various sections • Interfaces differ • Abstract HW • Usage of header/packets for communication • Minimize communication overhead and data transfer hence power consumption • Widens over all intelligence of systems… every one can contact with every one else • Distribution of computational power over nodes • Makes a distributed networks.. Every part can communicate • With every other part/node in network... • Even between the sub systems.. • Network distribution can be…
Packet Based Approach (2) • Single header… beyond peer to peer • Camera to camera… • Network to network… • No separate communication channel.. Just addressing through headers.. • Nodes via UID… Subsystem via flags.. • Receiving node distributes info within itself
WiCa OS • Based on TinyOS • Round Robin • Interrupt based… 8051 timer used • Task switching can be enabled or disabled by kernel
Application Execution • Divided into two parts • Low level pixel processing • Performed in IC3D • High level processing • Sorting Data • Interpreting Results • Passing information to network • Three type of Communication • Serial communication via DRAM • DRAM Shared between 8051 and IC3D • I2C Communication • To synchronize the code in 8051 and IC3D • Interrupts • To notify 8051 about special events
PC Side Control • WiCap (Wireless Camera Programmer) • Win32 Application in C++ • AquisGrain • USB Based • UART based PCB • Re-programming, Administration, Management and Application Control • Translates commands into sequence of packets/messages and delivers them to network via the communication HW
Results and Future • Software Stack explained • Communication protocol simplified • Less communication costs/overhead • But… • Only star network supported • Though nodes don’t see each other, but coordinator must see both • Limit on distance between two nodes • Solution • Increase coverage, use ZigBee II in WiCa’s next versions • WiCa GUI to increase usability and view the memory contents of WiCa
Evaluation • Hardware • Dual cam • SD interface • LCD interface • Integration (prototype) • Software • Network Ready • Framework ready • Code only functionality • Only star network supported • Not specified • Network details • Power management • Code structure, headers