James L. Massey's Contributions in the Early Years of Spread-Spectrum Communication Theory Research

During his long and illustrious research career, James L. Massey (1934-2013) devoted his attention to spread-spectrum communications very infrequently and then only for brief periods of time. In a short summer study for NASA in 1969, his research in sub-baud coding theory produced several concepts and techniques that are very important in the analysis and design of sequences for certain applications of direct-sequence spread spectrum. Massey never published his work on sub-baud coding theory in a journal, and his contributions went unnoticed until several years later when he presented some of his findings at the Allerton Conference. We provide a tutorial survey of Massey's concepts, tools, and sequence optimization criteria that have been employed by other researchers for the past four decades. Extensions of Massey's sequence-optimization concepts to other performance criteria are reviewed.