Codebook Design

An M x N codebook is a set of N vectors each of which is an M-dimensional vector. The maximum magnitude of inner products between a pair of distinct vectors (aka. coherence) indicates the similarity or geometric distance of the vectors, which is an important measure of codebook design. A codebook that has the coherence meeting the Welch bound equality is called the MWBE codebook (or equiangular tight frame (ETF) in signal processing community). The optimal (MWBE) or near-optimal codebooks provide code vectors available for

• Code set for multiple channels or users in code-division multiple access (CDMA) communication systems

• Deterministic measurement matrix design in compressive sensing

• Digital fingerprinting codes to support many legitimate copies

• etc.

Our research interests include

• Codebook design using combinatorial concepts such as difference sets and optical orthogonal codes

• Codebook design associated with binary sequences

• Application of codebooks in communications, signal processing, and digital watermarking