U.S. Patent No. 6, 128,290, directed to wireless for single hose and multiple peripherals.

In “low duty cycle pulsed mode of operation,” each peripheral and the base station are allocated a subset of time slots for communications, allowing power down at other times (page 3).  The transmitters are “energized in low duty cycle RF bursts” (pages 4-5).  In an obviousness decision, the Board held that Natarajan taught the limitation by teaching scheduled access multi-access protocol for the mobile units, alleging it would have been plainly obvious to do the same in an base station (pages 5-9).  The obviousness is based on the power conservation, which is taught for battery-operated mobile devices and within the skill to apply to a base station (pages 9-10).  The Federal Circuit noted that reliance on common sense and common knowledge supplies a missing limitation only where unusually simple and particularly straightforward (page 11).  The Boards use of “ordinary creativity” was not enough (page 12).  Since a complex communications protocol is used, it is not unusually simple or particularly straightforward to apply low duty cycle to the base station (page 12).

Hindsight:  It does seem a simple thing to apply the duty cycle to the base station, but the complexities in the specification lead two Judges of the panel to think otherwise.  While a better written opinion by the Broad may have resulted in a different decision, the specification including details indicating complexity helps.  It may be better to include more detail even for simple seeming changes.