The relationship between Comcast Corp. and Sprint Nextel Corp. continued to deteriorate last week as the MSO filed a patent lawsuit in a Pennsylvania court against its erstwhile wireless partner.

Comcast and TVWorks LLC, the MSO's wholly owned video software subsidiary, allege that Sprint is infringing on four patents that the wireless carrier is using to help power a range of relatively core mobile services.

According to a copy of the suit filed on Feb. 17 and obtained by Light Reading Cable, here's a list of patents linked to the case and a quick rundown of which Sprint services Comcast claims are tied to the alleged infringements.

• No. 7,684,391: Communications System for Delivering Multimedia Internet Protocol Packets Across Network Boundaries. Comcast claims that Sprint's voice and data service using IP/MPLS backhaul or transport are infringing. Patent issued March 23, 2010.

• No. 6,885,870: Transferring of a Message. Comcast claims that Sprint's multimedia messaging service (MMS) products for picture mail, wireless video mail and mobile email infringe on this one. Patent issued April 26, 2005.

• No. 5,987,323: Starting a Short Message Transmission in a Cellular Communication System. Comcast alleges that Sprint short message service (SMS) products such as Vision Pack, unlimited texting, wireless texting and wireless premium test messaging plans infringe. Patent issued Nov. 16, 1999.

• No. 6,112,305: Mechanism for Dynamically Binding a Network Computer Client Device to an Approved Internet Service Provider. Comcast (via its TVWorks unit) claims that Sprint wireless data products, including mobile broadband USB models and PCMCIA wireless cards offered under the carrier's 3G Mobile Broadband Connection and PowerVision plans infringe. Patent issued Aug. 29, 2000.

Comcast is seeking an injunction, plus attorney fees and undisclosed compensatory damages. Sprint declined to comment.

Why this matters
It's pretty clear that Comcast and Sprint aren't friends anymore. Comcast's suit comes about two months after Sprint sued the MSO and other former cable partners for allegedly infringing a dozen patents tied to VoIP services.

Comcast's latest legal maneuver also comes as it phases out sales of Sprint's 3G data service and Clearwire LLC's WiMax offering and continues to roll out service bundles with new wireless partner Verizon Wireless.

For more

Catch up on Comcast's recent mobile history.

• Sprint VoIP Patent Suit Targets MSOs
• Comcast, TW Cable to Halt Clearwire Sales

• VZ Wireless, Comcast Duo Plays San Francisco
• Verizon Wireless: Cable’s New BFF

— Jeff Baumgartner, Site Editor, Light Reading Cable