How patent trolls hurt the American economy

Patent trolls — entities that hoard patents, not to innovate but to litigate — are at it again. This time, a company called Freedom Patents has launched a fresh wave of litigation complaints targeting technology companies including T-Mobile, Samsung and Cisco.

This is the second campaign by Freedom Patents against wireless antenna technology. The grounds for its case rest on three outdated Mitsubishi patents, and the company is attempting to extract a large settlement from mobile communication...