Separation of time-varying multipath arrivals by converting their time delays into their frequency reallocations

• Autorzy: Kebkal K. G. , Bannasch R.
• Języki publikacji: EN

Abstrakty

EN

Multipath propagation causes the transmitted signal to take numerous, time-varying different length paths to receiver. Exploitation of conventional frequency-constant carrier signals for communication over underwater acoustic channels typically shows that intricate mutual time variations of multipath arrivals create a serious problem for equalizers to compensate for non-stable interferences. Communication over such channels can be, however, substantially improved by using not a conventional constant-frequency carrier but a carrier consisting of a sequence of steep sweeps. The method provides significant processing improvement enabling clear separation of multipath arrivals by converting their time delays into their frequency reallocations. When despreading the signal, the best suitable multipath can be filtered not as traditionally in time domains, applying complex equalizers, but infrequency domains via usual band-pass filters. An important aspect is that every multipath is separated together with its individual time-varying phase impairments, obtained with the signal during its propagation over a certain path, whereas signal impairments, specific for a given path, are completely separated from other signal impairments delivered by the signal during its propagation over every different path.

• Wydawca: Polskie Towarzystwo Akustyczne. Oddział Gdański
• Czasopismo: Hydroacoustics
• Rocznik: 2001
• Tom: Vol. 4
• Strony: 119--126
• Opis fizyczny: Bibliogr. 2 poz., rys.

Twórcy

autor

Kebkal K. G.

• State Oceanatrium of Ukraine, Epronovskaya 9,335024 Sevastopol, Ukraine
• EvoLogics Inc.: Ackerstr. 71-76 (ACKI) 13355 Berlin, Germany

autor

Bannasch R.

• EvoLogics Inc.: Ackerstr. 71-76 (ACK I) 13355 Berlin, Germany

Bibliografia

• 1. A. Catipovich. Performance limitations in underwater acoustic telemetry. IEEE J. of Oceanie Eng., 15(3),205-216,1990.
• 2. K. KebkaI and R. Bannasch (2000) Implementation of a Sweep-Spread Function for Communication over Underwater Acoustic ChanneIs. Proceedings Ocean s 2000 MTS/IEEE Conference in Providence, Rhode Island, 11-14, September, 2000. Vol. 3, pp. 1829 - 1837.