Multi-Channel Interference Measurements for Wireless Sensor Networks

This paper presents measurements of radio interference using "ambient munode" sensor nodes. By varying distances and frequencies we get a measure of the interference caused by transmissions on adjacent bands. Our observations show that adjacent spectrum interference influences the data delivery, considerably. Channels should be separated in the spatial or in the frequency domains if interference is to be avoided. In addition, the distance to simultaneous transmitters and the number of simultaneous transmissions are highly correlated with channel spacing. Therefore, channel spacing can be adjusted according to spatial distances so that multiple concurrent transmissions can be performed without interference. We also give proposals for further investigation on the usage of this correlation that are relevant to the design of future multi-channel protocols