BigBand Networks has brought suit against Imagine Communications, charging the latter with infringing three patents that cover advanced video processing and bandwidth management techniques.

The suit, filed in the United States District Court for the District of Delaware, alleges that Imagine products willfully infringe claims of BigBand's U.S. Patents Nos. 6,937,619, 6,999,477 and 7,058,087. The lawsuit seeks injunctive relief, along with damages for willful infringement.

Five of Imagine Communications' top executives - including the company's founders and CEO - are former BigBand employees.

Imagine’s initial product is the Quality On Demand Gateway, which the company describes as incorporating a new method of statistical multiplexing for the MPEG-2 VOD market. The company claims the QOD Gateway provides up to 15 variable bit rate (VBR) VOD streams that can share the same 256 QAM channel with equivalent quality relative to today’s maximum of 10 constant bit rate (CBR) VOD streams.

Separately, Liwest Kabelmedien GmbH, the second largest cable operator in Austria, has deployed BigBand’s Cuda CMTS to deliver high-speed data and voice services to subscribers near the city of Linz. BigBand said Liwest is also testing its M-CMTS technology.