Neava AB

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Algorithm for low energy consumption over WPAN.

In order to connect smart units with limited energy resources via TCP/IP, Neava has developed an algorithm for the efficient control of the power in wireless LANs (IEEE 802.15.4 / Zigbee) and a minimal use of system resources without creating adverse effects.


Adaptive Quality Control in IEEE 802.15.4

The last decade has seen an explosive growth in the domain of smart objects. Smart objects are small computers, often equipped with a sensor and a wireless communication device. Today smart objects are embedded in everything from everyday objects like car keys to industrial machinery.
A vision for the future is to connect these smart objects into an 'Internet of things' where they can exchange information with each other and make better decisions based on that information. This would open up a whole new dimension of applications for smart objects.


Smart objects usually have limited resources when it comes to computing power, memory and energy. The IP protocol has for a long time been deemed unsuitable for these reasons, but has in the last years been proved to work on smart objects as well. This is good news, because IP has shown to be a scalable, robust and long-lived communication protocol that supports a wide range of applications, devices and underlying protocols.


There are however obstacles in realizing the 'Internet of things' and one of these obstacles is conserving energy. Since smart objects usually have a limited power supply, e.g. batteries, and communicate wirelessly, communication has to be as energy efficient as possible. One way to accomplish this is to control a smart object's transmission power dynamically and optimally. Not only does this save energy on transmissions, but can avoid costly retransmissions caused by interference and reduce other interference related problems like overhearing.


In this Master Thesis we develop an adaptive transmission power control algorithm for TCP/IP and the underlying low-rate protocol standard IEEE 802.15.4. Using a closed-loop control system based on extended TCP acknowledgments called Quality Acknowledgments (QACKs) we show that it is possible to control transmission power effectively using only minimal system resources, overhead and without causing ill effects.