Wi-LAN Inc. (Toronto: WIN) (Nasdaq: WILN) has thrown the book at three major US MSOs, claiming that their use of Docsis-based channel bonding technologies infringes a patent issued in the late 1990s.

The lawsuit, filed in the US District Court for the Eastern District of Texas on November 19, alleges that Comcast Corp. (Nasdaq: CMCSA, CMCSK), Time Warner Cable Inc. (NYSE: TWC), and Charter Communications Inc. , are infringing on US Patent No. 5,761,602, which describes a "Hybrid Multichannel Data Transmission System Utilizing a Broadcast Medium." (See Wi-LAN Sues 3 Cable MSOs .)

More specifically, the complaint (PDF) argues that those MSOs are marketing and selling Docsis 2.0 and Docsis 3.0 products and services that perform "Dynamic Channel Change" and "Channel Bonding" -- features that, Ottawa-based Wi-LAN claims, are covered in the '602 patent

Based on the wording of the complaint, Wi-LAN may end up targeting more than just Comcast, Charter, and TWC.

"Any cable systems, or cable modem products used in such cable systems, that arecapable of performing the Dynamic Channel Change and/or Channel Bonding features of theapplicable DOCSIS standards necessarily infringe one or more claims of the ‘602 patent," the company noted.

Docsis 3.0, by way of example, bonds multiple 6MHz channels to product burst speeds in excess of 100Mbit/s. The baseline CableLabs specs for D3 requires that cable modems are capable of bonding at least four upstream channels and four downstream channels.

Why it's important
WiLAN's lawsuit enters the fray just as cable, including the three MSOs cited in the complaint, has started to deploy D3-based high-speed Internet services broadly. Comcast, which has Docsis 3.0 deployed to more than 83 percent of its footprint, recently introduced a 105Mbit/s (downstream) tier. (See Comcast's Target: 105-Meg D3 Downstream .)

WiLAN's suit also represents the latest attempt by a patent and licensing firm to file a suit centered on cable-based, high-speed Internet technologies.

Rembrandt IP Management LLC 's bid to squeeze royalties and license fees out of several major US cable operators and cable modem vendors failed last year, after a Delaware judge rejected Rembrandt's claims that the cable group was infringing on several data-over-cable technology patents. (See Court Sides Against Cable Modem Patent Troll and MSOs Try to Brush Off Rembrandt Patents.)

Comcast, Charter, and TWC declined to comment on the WiLAN complaint, with the first two noting that they have yet to be served with the complaint. "However, when the time is appropriate, we will take all steps necessary to defend ourselves," a Charter spokeswoman said.

WiLAN claims to have a portfolio of more than 970 patents, and sells a range of 3G handsets, WiFi-based laptops, DSL routers, and WiMax base stations. In 2006, it became a patent troll, or, in its words, decided "to focus its business on developing, protecting and monetizing patented inventions."

Here's a quick list of some of its patent-related handiwork:

— Jeff Baumgartner, Site Editor, Light Reading Cable