Multipath effects of FSK with frequency-discriminator detection

Abstract

We analyze how multipath effects, namely, errors due to channel-induced intersymbol interference, influence the error probability of frequency shift keying (FSK) with frequency-discriminator detection. We first introduce a new mathematical technique that allows insights into the error mechanisms. This technique is also capable of dealing with frequency shifts of the multipath components, postdiscriminator filtering, and nonlinearities in the discriminator. We then show that increasing the modulation index decreases the error floor, especially in the presence of frequency shifts. We also discuss the differences between prediscriminator and postdiscriminator filtering and show that an integrator is the best postdiscriminator filter.

Statistical properties of the delay spread in a two path mobile radio with Nakagami fading channel

“…The rms delay spread (defined as the second central moment of the power delay profile) is considered to be the major cause of error floor in high data rate mobile systems [3][4][5][6]. It was reported in the literature that the error floor is proportional to the square of the normalized (with respect to the bit, or symbol period) delay spread [6].…”

Reduction of the error floor of binary fsk by nonlinear frequency discriminators

“…For the computation of the error floor, we use a method that we recently introduced in [12]. In the first step, we write the received signal as…”