Signal design for approximately synchronized CDMA system without co-channel interference using pseudo-periodic sequences
N. Suehiro · 2002
A signal design is proposed for a CDMA system that is approximately synchronized. The signals are called pseudo-periodic sequences. The set of pseudo-periodic polyphase sequences are introduced from a set of periodic polyphase sequences with ideal autocorrelation for small shifts and zero crosscorrelation for all shifts. The system works without co-channel interference, even when the signals are modulated by data. The number of sequences can be infinite, so the security of the channel is very good, when the sequences are assigned secretly. Data assigning methods for signals are also proposed by designing codewords using "coded addition of sequences" or modulated orthogonal sequences.>