Optimal short-range CDMA codes of length 16 for wireless communications

Rademacher-Walsh (RW) functions are optimal short-range CDMA codes in the sense that they offer the least sensitivity to time base error due to propagation delay differences. Unfortunately, they do not offer a good power spectral density (PSD). There were two approaches examined for improving the PSD. The first approach provides an improved PSD through spreading the RW functions with a long PN code while increasing sensitivity to time base error. The second method ensures that the system is less sensitive to time base errors by using a fixed sequence of the optimal set of RW functions based on cross-correlation values. Thus, for short-range applications RW functions may offer superior performance to that achieved by conventional CDMA