Repozytorium publikacji - Politechnika Gdańska

A shallow underwater acoustic communication channel is characterized by strong multipath propagation. The signal reaching the receiver consists of a direct waveform and a number of its delayed and suppressed replica. A significant time dispersion of the transmitted signal and selective fading of its spectrum are observed. Coherence bandwidth defines maximal bandwidth, wherein the channel amplitude characteristic remains constant and its phase characteristic is linear. It is one of the channel transmission parameters that determine the physical layer of data transmission. Coherence bandwidth can be calculated on the basis of the channel impulse response, measured by the correlation method with the use of wideband frequency modulated signals or pseudo-random binary sequences. Both types of probe signals have an impulse-like autocorrelation function whose influence on the impulse response estimate is often considered as negligible. However, probe signals practically used in measuring systems have a limited bandwidth, which causes their correlation properties to be different than in the truly wideband case. This has a direct impact on impulse response and transmission parameters estimates. In particular, the coherence bandwidth can differ significantly depending on the probe signal used. The paper proposes a method of correction of the probe signal influence on the estimate of channel coherence bandwidth.

Autorzy

• dr hab. inż. Iwona Kochańska link otwiera się w nowej karcie ,
• dr inż. Jan Schmidt link otwiera się w nowej karcie