Comprehensive study of spectrum utilization for 802.11b/g/n networks

The rapid proliferation of newly developed wireless technologies has created an ever-increasing demand for additional radio spectrum. Because most usable bands have been already allocated, spectrum occupancy measurements are essential for wireless networks planning and deployment. Duty cycle is a measure of channel occupancy. As the amount of data traffic on the network increases, the duty cycle percentage increases, causing increased interference with other network devices using the same band. This paper provides comprehensive, systematic experimental measurements of spectrum occupancy in the 2.4GHz Industrial, Scientific and Medical band for multiple communicating 802.11 networks. Duty cycle was measured for various 802.11 combination protocols including 802.11b, g and n, at different throughput levels for each node in the network. Measurement software were developed using Labview. Experiments were validated for time and frequency domains. This work can assist technology developers to mitigate interference effects suffered from Wi-Fi by varying device transmission parameters and accommodating for measured duty cycle. Likewise, spectrum planning for the overcrowded Industrial, Scientific and Medical band can be improved.