Rockstar Consortium, the group that holds former Nortel patents and is backed by Apple, Microsoft, BlackBerry, Ericsson and Sony, is being sued by a group of cable companies.

Rockstar has also flexed its muscles in the mobile space, filing lawsuits against Google, Samsung and other Android handset vendors in November last year.

In the lawsuit filed in a Delaware federal court, five cable companies claim Rockstar refused to discuss licensing terms with them and is demanding royalties for unspecified patents.

The suit also claims that Rockstar has forced its legal targets into non-disclosure agreements to stop them discussing the issue with other companies.

The action requests that the court punish Rockstar for conducting an illegal conspiracy and for misusing the patents it holds.

In earlier, separate actions, Google was sued by Rockstar for allegedly infringing seven patents, covering technology that matches internet search terms and advertising.

The search giant has filed a lawsuit to protect companies making devices using Android from Rockstar’s actions.

The patents owned by Rockstar were bought in a 2011 auction for $4.5 billion, following the bankruptcy of network vendor Nortel, their previous holder.

Larger cable companies, including TimeWarnerCable, are already engaged in legal battles with Rockstar, which sued them in December.

In his Radio Free Mobile blog, industry analyst Richard Windsor wrote that Rockstar is in a difficult position as it is meeting more resistance from companies regarding the licensing of its patents, and is under pressure from its heavyweight owners to produce a decent return.

These factors are likely to be driving the more aggressive approach now being taken by the consortium.

Suggesting that Rockstar is looking at different approaches, Bloomberg reported in December that the patent consortium was in talks to sell some of its intellectual property.

In January, a deal was inked to sell “over 100 patents and patent applications” to “intellectual property development company” Spherix.