Motorola Inc. (NYSE: MOT) said Friday that it has bought up RadioFrame Networks Inc. 's iDEN base station business for an undisclosed sum. (See Moto Buys RadioFrame's iDEN Biz.)

Motorola says that it can use the firm's smaller and lower-cost iDEN architecture where the RadioFrame technology can facilitate the use of entirely separated spectrum bands allocated to carriers, particularly in markets outside the U.S. The business will be incorporated in Motorola's Home & Networks Mobility unit, which may itself be up for sale. (See Moto May Be Mulling Set-Top Sale and Huawei Seen as Likely Moto Suitor.)

Unstrung first revealed that RadioFrame was struggling in difficult economic times back in March of this year. The Redmond, Wash.-based firm closed down its European office -- while stressing that it was active in the U.S. -- and said it was getting out of the customer equipment side of its femtocell business, but would continue to make home base station chips. (See RadioFrame Exits Femtocell Biz.)

There have been industry rumors since then that the femto chip business was also up for sale. RadioFrame has never confirmed this, however.

For its part, Motorola has been on a mini acquisition and investment spree recently. As well as the RadioFrame buyout, Motorola announced Monday a deal to buy IPTV specialist BitBand . (See Moto to Buy BitBand.) The company also put money into chipmaker Sequans Communications . (See Sequans Gets VC for LTE.) — Dan Jones, Site Editor, Unstrung