What is the noisy white circle on my minimap?
What you're seeing is a friendly scrambler on the map.
Any enemies that travel inside the static circle will have their radar jammed.
We have portable items jammers, radar, and trophy in MW3 to cause a stationary static circle once deployed. The recon drone shows on the minimap with one of these circles on it, it is mobile, and it jams enemy radar in its proximity.