Sprint Nextel (NYSE:S) has begun the process of taking control of its longtime networking partner Clearwire (UNKNOWN:UNKNOWN).

The third-largest U.S. mobile carrier made a regulatory filing dated today indicating that it intends to buy enough shares from Eagle River Holdings to give it a 50.4% voting interest in the perennially struggling Clearwire. Sprint currently owns 48% of Clearwire's voting shares.

The impetus to seek control of Clearwire seems to be the agreement by Japanese mobile operator Softbank to buy 70% of Sprint for $20 billion. According to The Wall Street Journal,  people familiar with the matter have said the deal came with a caveat from Softbank's financiers that Sprint would have control of Clearwire and its cache of wireless spectrum licenses.

Fool contributor Dan Radovsky has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.