ERICSSON INC. v. INTELLECTUAL VENTURES LLC, 16-1671, decided May 29, 2018

U.S. Patent No. 6,952,408, directed to frequency hopping with time division multiplexing.

The claim recites “changing” between RF channels, but the prior art indicated frequency hopping as optional through a reference to the GSM standard (page 15).  Any differences are in unclaimed implementation (pages 15-17).

Hindsight: a creative argument based on claiming an event where the prior art shows that event as optional.  Claim 1 appears to be overly broad, which may have allowed the lawsuit but hurt in the validity analysis.