Error performance of π/2-TFSK 2-bit differential detection over the band-limited multipath interfering mobile radio environments

A modulation scheme named π/2-TFSK shows a superior error performance to MSK (minimum shift keying) in a frequency-selective mobile radio channel. The 2-bit differential detection of π/2-TFSK with a raised-cosine type premodulation lowpass filter is analyzed under the frequency-selective mobile radio environment, and a better error performance than MSK is demonstrated. These characteristics are confirmed through an experimental simulation in the laboratory. As the frequency-selective fading model a two Rayleigh-fading-wave model with a constant group time delay is adopted. The system is implemented with a transmission rate of 64 kb/s. and a quadrature-type modulator is used with the carrier frequency of 900 MHz band. The RAM-type demodulator is used as the differential detector