Long-duration Reliability Tests of Low Power Wireless Sensing and Control Links in an Office Environment

The author performs reliability tests on a low power 802.15.4-based wireless network capable of multi-hop routing, by observing the amount of connection loss incidents of each node and route over several days. The results show a high reliability and little sensitivity to external interference. However, the tests also show that, to further improve reliability, commonly used techniques, like selecting routes with better hop-level link quality indicator values, would not have worked. The author also performed duration tests of the 802.15.4 beacon request (active scan) mechanism. The results show that this mechanism is not a very reliable guide for selecting a route when it is used only once. Longer-term statis-tics based on multiple beacon requests, or on other packet reception metrics, can be a better guide to actual connectivity conditions.