Dariush Divsalar

Dariush Divsalar
Associated organizations
Jet Propulsion Laboratory
Fields of study
NASA Exceptional Engineering Achievement Medal


For more than three decades, Dariush Divsalar’s innovative contributions to information theory and communications technology have provided advancements leading to more reliable and efficient near-capacity transmission and reception of data for wireless networks and deep space communications. Dr. Divsalar’s channel coding innovations have led to state-of-the art technology and represent the most advanced high-performance coding schemes standardized for deep space communications today. Channel codes are used to protect data transmission and storage in the presence of noise or errors. Perhaps best known for his work on understanding turbo codes, which were the first practical codes to closely approach channel capacity, Dr. Divsalar optimized and standardized turbo codes for deep-space applications. He also co-invented a new class of protograph-based low-density parity-check (LDPC) codes for efficient information transfer over noisy channels. Known as Accumulate Repeat Accumulate codes, the technique is based on accumulators, puncturing, and a precoder to further improve performance. These new codes are themselves an enhanced version of Repeat Accumulate codes previously co-invented by Dr. Divsalar. These new protograph-based LDPC codes have become Consultative Committee for Space Data Systems (CCSDS) international standards and are being used in NASA missions. Dr. Divsalar has also contributed significantly to bandwidth-efficient coded modulation, with work that paved the way to trellis coded modulation design for wireless fading channels that became the basis of the modern approach of bit-interleaved coded modulation. This is an integral component of today’s WiFi and 4G wireless systems. He also developed the parallel partial interference cancellation scheme for multiuser systems, analyzed it, and showed its superiority in improving code division multiple access (CDMA), which was an important building block of multiple access communications systems. Dr. Divsalar’s latest discoveries are impacting the use of wireless, deep space, and free-space optical communications for high-speed data links.

An IEEE Life Fellow and recipient of the NASA Exceptional Engineering Achievement Medal (1996), Dr. Divsalar is currently a senior research scientist with the Jet Propulsion Laboratory, Pasadena, CA, USA.