Strongly Ramanujan graphs coding theory, prime-phase sequences, and combinatorics

The authors give constructions of Ramanujan graphs from algebraic coding, prime-phase sequences, and combinatorics. The graphs constructed have several advantages. The main advantage is that our constructions use only elementary algebraic methods (as opposed to deeper results from algebraic geometry, number theory, or representation theory) in construction and in determining various parameters, such expansion coefficients, diameters etc. These graphs also are better compared to known graphs in various respects