ERROR FLOORS IN THE SATELLITE AND LAND MOBILE CHANNELS

In a satellite mobile channel (SMC) and land mobile channel (LMC) because of fading and nonlinear power amplifiers, constant envelope modulation and noncoherent detection methods may outperform other schemes. Differential phase shift keying (DPSK) with differential phase detection (DPD) or frequency shift keying (FSK) with either DPD, limiter discriminator integrator detection (LDID) or limiter discriminator detection (LDD) are suitable candidates. The probability of error in a digital communication scheme is a decreasing function of signal to noise ratio (SNR) and usually decreases to zero when SNR tends to infinity. This does not happen in the SMC and LMC due mainly to fading. An error floor is the residual error probability when SNR is infinity. That means that the error probability in the system is limited below by the error floor. In this paper we present formulas for the error floor for DPSK-DPD, FSK-DPD, FSK-LDID, and FSK-LDD. We compute the error floor for M = 2, 4, 8 as a function of Doppler frequency, modulation index and ratio of powers in the specular and diffuse signal components.