Abstract:

A new kind of non-single frequency wave band pass modulation method named sine non-linear chirp keying (SNCK) is proposed which uses sinusoidal non-linear chirp signals as carriers. Adjusting parameters such as timebandwidth product or the frequencies of frequency variation curve, SNCK can be used in wireless communication systems with different qualities of service or channel characters. More importantly, SNCK has a strong ability to suppress Doppler frequency shift by using non-single frequency wave as carriers. The mathematical model of SNCK is set up, the design method of orthogonalization is given, and the performances, such as frequency domain energy concentration of modulation signals and adaptabilities of channels, are analyzed. Theoretical analysis and experimental results show that SNCK has the same suppression ability of average Gaussian white noise and frequency domain energy concentration compared with the very minimum chirp keying (VMCK), and a stronger Doppler frequency shift suppression ability than the minimum shift keying (MSK). SNCK can be used as a kind of band pass modulation scheme for variable rate wireless communication systems in communication terminals with high mobile speed.