Implementing A Processor Independent, Battery Powered Wireless

Implementing a processor independent, battery powered wireless mesh network

Submitted by Ranjit Saikia (1AC03EC035)

Abstract.. 





There are certain wireless technologies working for Embedded system applications. But all have some drawbacks, for e.g., cost factor, design complexity, processor dependence and power consumption. This paper describes an alternative approach that mitigates these drawbacks.

Topics of Discussion..  



  

Existing system. Wireless Mesh Network for existing system. An introduction to SNAP (Synapse Network Application Protocol). Implementing SNAP based design. Advantages and Applications. Future Work and Conclusion.

Existing System..

Wireless Mesh Network for Existing System.. In a conventional wireless mesh network implementation:  the stack is closely tied to a particular microcontroller.  Creating the wireless applications requires extensive C/C++ programming and embedded expertise.  To increase battery life, its end devices have to be in sleep mode but its routers have to remain active on external power. Fig. 1..

An Introduction to SNAP.. 





SNAP is abbreviation for “Synapse Network Application Protocol”. By comparison, a wireless network based on SNAP software stack is instant-on, self-forming, and selfhealing. A high-level view of the SNAP software stack is illustrated in fig. 2..

The SNAP Software Stack Model.. 



 

Runs efficiently on cost-effective 8-bit microprocessors. Very small memory footprint of only 40 KB compared to conventional stack, which consume 60 KB or more. This is designed for portability. Two key aspects to this portability are: HAL and SNAPpy Virtual machine.

Continued.. 





The HAL provides a layer of abstraction between the main body of the software stack and the physical world. The process of porting the stack to a new processor requires modification only to the “thin slice” of the HAL. SNAP employs industry standard 802.15.4 packet interface in addition to IEEE 802.15.4 physical layer.

Continued.. 





The combination of SNAP and Python is known as “SNAPpy”. User applications that run on SNAP based nodes are created in high-level Python scripting language. End-user wireless applications are compiled into processor-independent “byte-code” that is run on the SNAPpy virtual machine.

SNAP based Wireless Mesh Network.. 







SNAP protocol can theoretically support up to 16 million nodes in a single network!! Being Mesh Network, no single point of failure!! Routes between nodes do not have to be pre-configured by the user!! When a node is powered-up it is automatically integrated into the network, and become fully operational in a fraction of seconds!!

Ultra Low-Powered Mesh Routing.. 







For a constant active node, two AA batteries can power it for only a couple of days. Hence not acceptable in terms of resource requirements and expense. The solution is for the nodes to alternate between being “awake” for a short time and then entering a “sleep” mode. Hence consume dramatically less power. fig. 3&4..

SNAP Based Proposed System..

Advantages.. 





A SNAPpy application can run on any processor without requiring any modification or re-compilation. Python language encourages development of higher quality, more maintainable code. The result of “sleepy Mesh” can extend the battery life of each node from a little over two days to more than a year!!

Applications.. 





Mesh networks may involve either fixed or mobile devices. In difficult environments such as emergency situations, tunnels and oil rigs to battlefield surveillance. High speed mobile video applications on board public transport or real time racing car telemetry.

Future Work.. 





Study in battery technology reveals that discharging of a battery is nonlinear. A mathematical model can be introduced on battery discharging duration and lifetime for wireless mesh networks. An approximation algorithm called the spanning tree scheduling (STS) can greatly improve the lifetime, data throughput and power consumption efficiency of a wireless mesh network.

Conclusion.. The SNAP software stack re-defines wireless networking. Networks based on this high-performance, low power , small-memory-footprint stack are self-forming, instant-on, and selfhealing.

………………………………………………….