Wireless Range Testing

Outdoor with maximum transmit power % Success Fall off Drop off Meters

Outdoor with minimum transmit power % Success Fall off Drop off Meters

Indoor with minimum transmit power % Success Steep fall off drop off Meters

Conclusions Many ZigBee / IEEE 802.15.4-based wireless data networks operate in the 2.45–2.4835 GHz band, and so are subject to interference from other devices operating in that same band. To avoid interference from IEEE 802.11 networks, an IEEE 802.15.4 network can be configured to only use channels 15, 20, 25, and 26, avoiding frequencies used by the commonly used IEEE 802.11 channels 1, 6, and 11.(Wikipedia) Inconsistent results due, most likely, to background RF noise Broadcasting station on Hampton WODU radio Wireless networks Cell phones Bluetooth Car alarms This requires further investigation

Conclusions At shorter ranges (<10m) transmission seem to be reliable (>95%) at all times. Less susceptible to background noise At larger ranges (>25m), it is possible that communications will work fine , but repeated tests show that reliability is very low. Most tests at higher ranges will show consistent low (5%<X<60%) transmission success rates. Occasionally, for a brief window of time, transmissions at a large range will have an unusually high rate (80%<X<95%) of success.

Conclusions At medium ranges (10m<X<25m) communications usually have consistent reliability, but sometimes success rates drop dramatically to below 20% for a brief period of time. All of these inconsistencies are most likely due to background noise and interference. Testing was done continuously until “likely” results were obtained at the given distance. Most of these spikes in reliability (either above or below the normal) were ignored for graphing, but noted for consideration.

Conclusions Orientation of the mote has an effect on its transmission range. Transmissions became unpredictably good/poor as I moved the mote to varying distances. I tried orienting the mote differently by facing it in different directions. From this, I found that a higher success rate could be obtained by facing the side with the antennae away from the base station. This seems counter-intuitive, but it seemed to work best in testing.