Professor Rao's interests are in the areas of digital signal processing, estimation theory, and optimization theory, with applications to digital communications, speech signal processing, and human-computer interactions. His research work has spanned several areas in signal processing including finite wordlength effects in digital filters, adaptive filtering, model based spectral estimation, subspace based direction of arrival estimation methods, speech compression and recognition and space-time processing. His current interests in speech processing are in the area of speech coding where his group is involved in developing efficient and low complexity vector quantization techniques, and in speech recognition where the research efforts are focused on developing robust speech recognition techniques, in particular robust front-ends. In digital communications his research work is in the development of multiple antenna systems for improving the reliability and capacity of wireless networks. His group is also involved in the development of novel algorithms for computing sparse solutions to linear inverse problems which have many potential applications such as biomagnetic imaging, signal representation etc.