Alongside its Monday approval of Google's $12.5 billion acquisition of Motorola Mobility, the US Department of Justice (DoJ) also approved the purchase of over 6,000 highly coveted mobile tech patents of bankrupt Canadian firm Nortel Networks by a consortium of bigwig tech companies including Apple, Microsoft, and Sony.

The go-ahead by the DoJ implies that the Apple-led consortium of tech giants - which also include BlackBerry-maker Research In Motion, EMC and Ericsson - will make a combined payment of $4.5 billion for Nortel Networks' trove of patents and patent applications which are deemed to be notably vital to the future of mobile computing.

Nortel had agreed to the sale of the crucial patents to the six-company consortium, which bid under the name `Rockstar Bidco', in its 19-round bankruptcy auction in July last year.

The Nortel patents which have been bought by the six big tech companies chiefly pertain to wireless technologies which are used in handsets and tablets, including 4G data and data networking, optical devices, and semiconductors.

Incidentally, Google - which is among the `weak patent portfolio' companies in the mobile industry, and is attempting to build up its patent portfolio with the Motorola acquisition - also had also bid for the Nortel patents which, according to the DoJ, will be licensed and distributed by the Rockstar Bidco group to "certain partners."