Geometrically uniform frames

We introduce a new class of frames with strong symmetry properties called geometrically uniform frames (GU), that are defined over an abelian group of unitary matrices and are generated by a single generating vector. The notion of GU frames is then extended to compound GU (CGU) frames which are generated by an abelian group of unitary matrices using multiple generating vectors. The dual frame vectors and canonical tight frame vectors associated with GU frames are shown to be GU and therefore generated by a single generating vector, which can be computed very efficiently using a Fourier transform defined over the generating group of the frame. Similarly, the dual frame vectors and canonical tight frame vectors associated with CGU frames are shown to be CGU. The impact of removing single or multiple elements from a GU frame is considered. A systematic method for constructing optimal GU frames from a given set of frame vectors that are not GU is also developed. Finally, the Euclidean distance properties of GU frames are discussed and conditions are derived on the abelian group of unitary matrices to yield GU frames with strictly positive distance spectrum irrespective of the generating vector. Research Laboratory of Electronics, Massachusetts Institute of Technology, Room 36-615, Cambridge, MA 02139. E-mail: [email protected]. Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801. Email: [email protected].