ELBIT SYSTEMS LAND AND C4I LTD v. HUGHES NETWORK SYSTEMS, LLC, decided June 25, 2019, Means-plus-function

U.S. Patent No. 6,240,073 is directed to a reverse link in satellite communications (pages 2-3). The claims recite a “communication means for continuous transmission of data” and a “switching means” (page 4). The accused products used burst and longer communications for large files that are too big for bursts, so substantial evidence is provided of continuous (pages 6-8). For “switching means,” the structure in interpretation of the means-plus-function limitation includes an algorithm (page 8). The accused was found to perform in substantially the same way (pages 8-9). The same criteria for switching described in the specification are used in the accused device (page 9). The switching means requires the terminal, not the hub, to control switching (pages 9-10). Since the hub in the accused device acts based on a message from the terminal to control the switching, the terminal controls (pages 9-10).

Hindsight: Means-plus-function limitations may result in a number of requirements in claims. This may make infringement difficult and invalidity easier. Including alternatives in the specification may have broadened the interpretation, such as including which devices may control switching and various criteria for performing. When using a term like continuous, context may be important. There may be nothing continuous over all time, so indicating a range or ranges for continuous and/or using a relative comparison to burst may be helpful.