Multipath fading effects on carrier recovery of BPSK signal in digital radio

Tracking performance of the I-Q carrier recovery loop for BPSK signal in band-limited channel with multipath interference is analysed. The multipath fading channel is characterised by the Rummler´s simplified three-ray model (1979) for line-of-sight digital radio system. A closed-form expression for the phase-error variance related to the multipath interference, intersymbol interference and channel noise is derived. Excess phase offset induced from the multipath interference is also examined. The closed-form expression of the jitter variance can be evaluated numerically to assess the degradation of synchroniser performance. Asymptotic limits of the performance are also discussed.<>